[PATCH] relay: migrate from relayfs to a generic relay API
Original patch from Paul Mundt, sysfs parts removed by me since they were broken. Signed-off-by: Jens Axboe <axboe@suse.de>
This commit is contained in:
parent
b0e6e96299
commit
b86ff981a8
12 changed files with 1212 additions and 1290 deletions
12
fs/Kconfig
12
fs/Kconfig
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@ -859,18 +859,6 @@ config RAMFS
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To compile this as a module, choose M here: the module will be called
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ramfs.
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config RELAYFS_FS
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tristate "Relayfs file system support"
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---help---
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Relayfs is a high-speed data relay filesystem designed to provide
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an efficient mechanism for tools and facilities to relay large
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amounts of data from kernel space to user space.
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To compile this code as a module, choose M here: the module will be
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called relayfs.
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If unsure, say N.
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config CONFIGFS_FS
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tristate "Userspace-driven configuration filesystem (EXPERIMENTAL)"
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depends on EXPERIMENTAL
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@ -91,7 +91,6 @@ obj-$(CONFIG_AUTOFS4_FS) += autofs4/
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obj-$(CONFIG_ADFS_FS) += adfs/
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obj-$(CONFIG_FUSE_FS) += fuse/
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obj-$(CONFIG_UDF_FS) += udf/
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obj-$(CONFIG_RELAYFS_FS) += relayfs/
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obj-$(CONFIG_SUN_OPENPROMFS) += openpromfs/
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obj-$(CONFIG_JFS_FS) += jfs/
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obj-$(CONFIG_XFS_FS) += xfs/
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@ -1,4 +0,0 @@
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obj-$(CONFIG_RELAYFS_FS) += relayfs.o
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relayfs-y := relay.o inode.o buffers.o
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@ -1,190 +0,0 @@
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/*
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* RelayFS buffer management code.
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*
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* Copyright (C) 2002-2005 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp
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* Copyright (C) 1999-2005 - Karim Yaghmour (karim@opersys.com)
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*
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* This file is released under the GPL.
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*/
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#include <linux/module.h>
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#include <linux/vmalloc.h>
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#include <linux/mm.h>
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#include <linux/relayfs_fs.h>
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#include "relay.h"
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#include "buffers.h"
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/*
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* close() vm_op implementation for relayfs file mapping.
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*/
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static void relay_file_mmap_close(struct vm_area_struct *vma)
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{
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struct rchan_buf *buf = vma->vm_private_data;
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buf->chan->cb->buf_unmapped(buf, vma->vm_file);
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}
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/*
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* nopage() vm_op implementation for relayfs file mapping.
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*/
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static struct page *relay_buf_nopage(struct vm_area_struct *vma,
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unsigned long address,
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int *type)
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{
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struct page *page;
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struct rchan_buf *buf = vma->vm_private_data;
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unsigned long offset = address - vma->vm_start;
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if (address > vma->vm_end)
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return NOPAGE_SIGBUS; /* Disallow mremap */
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if (!buf)
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return NOPAGE_OOM;
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page = vmalloc_to_page(buf->start + offset);
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if (!page)
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return NOPAGE_OOM;
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get_page(page);
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if (type)
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*type = VM_FAULT_MINOR;
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return page;
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}
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/*
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* vm_ops for relay file mappings.
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*/
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static struct vm_operations_struct relay_file_mmap_ops = {
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.nopage = relay_buf_nopage,
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.close = relay_file_mmap_close,
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};
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/**
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* relay_mmap_buf: - mmap channel buffer to process address space
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* @buf: relay channel buffer
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* @vma: vm_area_struct describing memory to be mapped
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*
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* Returns 0 if ok, negative on error
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*
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* Caller should already have grabbed mmap_sem.
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*/
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int relay_mmap_buf(struct rchan_buf *buf, struct vm_area_struct *vma)
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{
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unsigned long length = vma->vm_end - vma->vm_start;
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struct file *filp = vma->vm_file;
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if (!buf)
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return -EBADF;
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if (length != (unsigned long)buf->chan->alloc_size)
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return -EINVAL;
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vma->vm_ops = &relay_file_mmap_ops;
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vma->vm_private_data = buf;
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buf->chan->cb->buf_mapped(buf, filp);
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return 0;
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}
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/**
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* relay_alloc_buf - allocate a channel buffer
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* @buf: the buffer struct
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* @size: total size of the buffer
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*
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* Returns a pointer to the resulting buffer, NULL if unsuccessful
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*/
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static void *relay_alloc_buf(struct rchan_buf *buf, unsigned long size)
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{
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void *mem;
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unsigned int i, j, n_pages;
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size = PAGE_ALIGN(size);
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n_pages = size >> PAGE_SHIFT;
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buf->page_array = kcalloc(n_pages, sizeof(struct page *), GFP_KERNEL);
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if (!buf->page_array)
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return NULL;
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for (i = 0; i < n_pages; i++) {
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buf->page_array[i] = alloc_page(GFP_KERNEL);
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if (unlikely(!buf->page_array[i]))
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goto depopulate;
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}
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mem = vmap(buf->page_array, n_pages, VM_MAP, PAGE_KERNEL);
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if (!mem)
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goto depopulate;
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memset(mem, 0, size);
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buf->page_count = n_pages;
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return mem;
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depopulate:
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for (j = 0; j < i; j++)
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__free_page(buf->page_array[j]);
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kfree(buf->page_array);
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return NULL;
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}
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/**
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* relay_create_buf - allocate and initialize a channel buffer
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* @alloc_size: size of the buffer to allocate
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* @n_subbufs: number of sub-buffers in the channel
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*
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* Returns channel buffer if successful, NULL otherwise
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*/
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struct rchan_buf *relay_create_buf(struct rchan *chan)
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{
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struct rchan_buf *buf = kcalloc(1, sizeof(struct rchan_buf), GFP_KERNEL);
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if (!buf)
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return NULL;
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buf->padding = kmalloc(chan->n_subbufs * sizeof(size_t *), GFP_KERNEL);
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if (!buf->padding)
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goto free_buf;
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buf->start = relay_alloc_buf(buf, chan->alloc_size);
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if (!buf->start)
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goto free_buf;
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buf->chan = chan;
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kref_get(&buf->chan->kref);
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return buf;
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free_buf:
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kfree(buf->padding);
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kfree(buf);
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return NULL;
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}
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/**
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* relay_destroy_buf - destroy an rchan_buf struct and associated buffer
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* @buf: the buffer struct
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*/
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void relay_destroy_buf(struct rchan_buf *buf)
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{
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struct rchan *chan = buf->chan;
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unsigned int i;
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if (likely(buf->start)) {
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vunmap(buf->start);
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for (i = 0; i < buf->page_count; i++)
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__free_page(buf->page_array[i]);
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kfree(buf->page_array);
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}
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kfree(buf->padding);
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kfree(buf);
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kref_put(&chan->kref, relay_destroy_channel);
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}
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/**
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* relay_remove_buf - remove a channel buffer
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*
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* Removes the file from the relayfs fileystem, which also frees the
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* rchan_buf_struct and the channel buffer. Should only be called from
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* kref_put().
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*/
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void relay_remove_buf(struct kref *kref)
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{
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struct rchan_buf *buf = container_of(kref, struct rchan_buf, kref);
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buf->chan->cb->remove_buf_file(buf->dentry);
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relay_destroy_buf(buf);
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}
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@ -1,12 +0,0 @@
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#ifndef _BUFFERS_H
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#define _BUFFERS_H
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/* This inspired by rtai/shmem */
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#define FIX_SIZE(x) (((x) - 1) & PAGE_MASK) + PAGE_SIZE
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extern int relay_mmap_buf(struct rchan_buf *buf, struct vm_area_struct *vma);
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extern struct rchan_buf *relay_create_buf(struct rchan *chan);
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extern void relay_destroy_buf(struct rchan_buf *buf);
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extern void relay_remove_buf(struct kref *kref);
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#endif/* _BUFFERS_H */
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@ -1,581 +0,0 @@
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/*
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* VFS-related code for RelayFS, a high-speed data relay filesystem.
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*
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* Copyright (C) 2003-2005 - Tom Zanussi <zanussi@us.ibm.com>, IBM Corp
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* Copyright (C) 2003-2005 - Karim Yaghmour <karim@opersys.com>
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*
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* Based on ramfs, Copyright (C) 2002 - Linus Torvalds
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*
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* This file is released under the GPL.
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*/
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#include <linux/module.h>
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#include <linux/fs.h>
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#include <linux/mount.h>
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#include <linux/pagemap.h>
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#include <linux/init.h>
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#include <linux/string.h>
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#include <linux/backing-dev.h>
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#include <linux/namei.h>
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#include <linux/poll.h>
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#include <linux/relayfs_fs.h>
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#include "relay.h"
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#include "buffers.h"
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#define RELAYFS_MAGIC 0xF0B4A981
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static struct vfsmount * relayfs_mount;
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static int relayfs_mount_count;
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static struct backing_dev_info relayfs_backing_dev_info = {
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.ra_pages = 0, /* No readahead */
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.capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK,
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};
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static struct inode *relayfs_get_inode(struct super_block *sb,
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int mode,
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struct file_operations *fops,
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void *data)
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{
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struct inode *inode;
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inode = new_inode(sb);
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if (!inode)
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return NULL;
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inode->i_mode = mode;
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inode->i_uid = 0;
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inode->i_gid = 0;
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inode->i_blksize = PAGE_CACHE_SIZE;
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inode->i_blocks = 0;
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inode->i_mapping->backing_dev_info = &relayfs_backing_dev_info;
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inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
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switch (mode & S_IFMT) {
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case S_IFREG:
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inode->i_fop = fops;
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if (data)
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inode->u.generic_ip = data;
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break;
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case S_IFDIR:
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inode->i_op = &simple_dir_inode_operations;
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inode->i_fop = &simple_dir_operations;
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/* directory inodes start off with i_nlink == 2 (for "." entry) */
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inode->i_nlink++;
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break;
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default:
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break;
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}
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return inode;
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}
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/**
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* relayfs_create_entry - create a relayfs directory or file
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* @name: the name of the file to create
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* @parent: parent directory
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* @mode: mode
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* @fops: file operations to use for the file
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* @data: user-associated data for this file
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*
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* Returns the new dentry, NULL on failure
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*
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* Creates a file or directory with the specifed permissions.
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*/
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static struct dentry *relayfs_create_entry(const char *name,
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struct dentry *parent,
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int mode,
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struct file_operations *fops,
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void *data)
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{
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struct dentry *d;
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struct inode *inode;
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int error = 0;
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BUG_ON(!name || !(S_ISREG(mode) || S_ISDIR(mode)));
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error = simple_pin_fs("relayfs", &relayfs_mount, &relayfs_mount_count);
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if (error) {
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printk(KERN_ERR "Couldn't mount relayfs: errcode %d\n", error);
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return NULL;
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}
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if (!parent && relayfs_mount && relayfs_mount->mnt_sb)
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parent = relayfs_mount->mnt_sb->s_root;
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if (!parent) {
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simple_release_fs(&relayfs_mount, &relayfs_mount_count);
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return NULL;
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}
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parent = dget(parent);
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mutex_lock(&parent->d_inode->i_mutex);
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d = lookup_one_len(name, parent, strlen(name));
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if (IS_ERR(d)) {
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d = NULL;
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goto release_mount;
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}
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if (d->d_inode) {
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d = NULL;
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goto release_mount;
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}
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inode = relayfs_get_inode(parent->d_inode->i_sb, mode, fops, data);
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if (!inode) {
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d = NULL;
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goto release_mount;
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}
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d_instantiate(d, inode);
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dget(d); /* Extra count - pin the dentry in core */
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if (S_ISDIR(mode))
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parent->d_inode->i_nlink++;
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goto exit;
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release_mount:
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simple_release_fs(&relayfs_mount, &relayfs_mount_count);
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exit:
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mutex_unlock(&parent->d_inode->i_mutex);
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dput(parent);
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return d;
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}
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/**
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* relayfs_create_file - create a file in the relay filesystem
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* @name: the name of the file to create
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* @parent: parent directory
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* @mode: mode, if not specied the default perms are used
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* @fops: file operations to use for the file
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* @data: user-associated data for this file
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*
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* Returns file dentry if successful, NULL otherwise.
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*
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* The file will be created user r on behalf of current user.
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*/
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struct dentry *relayfs_create_file(const char *name,
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struct dentry *parent,
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int mode,
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struct file_operations *fops,
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void *data)
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{
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BUG_ON(!fops);
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if (!mode)
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mode = S_IRUSR;
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mode = (mode & S_IALLUGO) | S_IFREG;
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return relayfs_create_entry(name, parent, mode, fops, data);
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}
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/**
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* relayfs_create_dir - create a directory in the relay filesystem
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* @name: the name of the directory to create
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* @parent: parent directory, NULL if parent should be fs root
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*
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* Returns directory dentry if successful, NULL otherwise.
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*
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* The directory will be created world rwx on behalf of current user.
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*/
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struct dentry *relayfs_create_dir(const char *name, struct dentry *parent)
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{
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int mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
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return relayfs_create_entry(name, parent, mode, NULL, NULL);
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}
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/**
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* relayfs_remove - remove a file or directory in the relay filesystem
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* @dentry: file or directory dentry
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*
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* Returns 0 if successful, negative otherwise.
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*/
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int relayfs_remove(struct dentry *dentry)
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{
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struct dentry *parent;
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int error = 0;
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if (!dentry)
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return -EINVAL;
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parent = dentry->d_parent;
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if (!parent)
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return -EINVAL;
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parent = dget(parent);
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mutex_lock(&parent->d_inode->i_mutex);
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if (dentry->d_inode) {
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if (S_ISDIR(dentry->d_inode->i_mode))
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error = simple_rmdir(parent->d_inode, dentry);
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else
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error = simple_unlink(parent->d_inode, dentry);
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if (!error)
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d_delete(dentry);
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}
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if (!error)
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dput(dentry);
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mutex_unlock(&parent->d_inode->i_mutex);
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dput(parent);
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if (!error)
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simple_release_fs(&relayfs_mount, &relayfs_mount_count);
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return error;
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}
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/**
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* relayfs_remove_file - remove a file from relay filesystem
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* @dentry: directory dentry
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*
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* Returns 0 if successful, negative otherwise.
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*/
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int relayfs_remove_file(struct dentry *dentry)
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{
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return relayfs_remove(dentry);
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}
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/**
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* relayfs_remove_dir - remove a directory in the relay filesystem
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* @dentry: directory dentry
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*
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* Returns 0 if successful, negative otherwise.
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*/
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int relayfs_remove_dir(struct dentry *dentry)
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{
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return relayfs_remove(dentry);
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}
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/**
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* relay_file_open - open file op for relay files
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* @inode: the inode
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* @filp: the file
|
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*
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* Increments the channel buffer refcount.
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*/
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static int relay_file_open(struct inode *inode, struct file *filp)
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{
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struct rchan_buf *buf = inode->u.generic_ip;
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||||
kref_get(&buf->kref);
|
||||
filp->private_data = buf;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_file_mmap - mmap file op for relay files
|
||||
* @filp: the file
|
||||
* @vma: the vma describing what to map
|
||||
*
|
||||
* Calls upon relay_mmap_buf to map the file into user space.
|
||||
*/
|
||||
static int relay_file_mmap(struct file *filp, struct vm_area_struct *vma)
|
||||
{
|
||||
struct rchan_buf *buf = filp->private_data;
|
||||
return relay_mmap_buf(buf, vma);
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_file_poll - poll file op for relay files
|
||||
* @filp: the file
|
||||
* @wait: poll table
|
||||
*
|
||||
* Poll implemention.
|
||||
*/
|
||||
static unsigned int relay_file_poll(struct file *filp, poll_table *wait)
|
||||
{
|
||||
unsigned int mask = 0;
|
||||
struct rchan_buf *buf = filp->private_data;
|
||||
|
||||
if (buf->finalized)
|
||||
return POLLERR;
|
||||
|
||||
if (filp->f_mode & FMODE_READ) {
|
||||
poll_wait(filp, &buf->read_wait, wait);
|
||||
if (!relay_buf_empty(buf))
|
||||
mask |= POLLIN | POLLRDNORM;
|
||||
}
|
||||
|
||||
return mask;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_file_release - release file op for relay files
|
||||
* @inode: the inode
|
||||
* @filp: the file
|
||||
*
|
||||
* Decrements the channel refcount, as the filesystem is
|
||||
* no longer using it.
|
||||
*/
|
||||
static int relay_file_release(struct inode *inode, struct file *filp)
|
||||
{
|
||||
struct rchan_buf *buf = filp->private_data;
|
||||
kref_put(&buf->kref, relay_remove_buf);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_file_read_consume - update the consumed count for the buffer
|
||||
*/
|
||||
static void relay_file_read_consume(struct rchan_buf *buf,
|
||||
size_t read_pos,
|
||||
size_t bytes_consumed)
|
||||
{
|
||||
size_t subbuf_size = buf->chan->subbuf_size;
|
||||
size_t n_subbufs = buf->chan->n_subbufs;
|
||||
size_t read_subbuf;
|
||||
|
||||
if (buf->bytes_consumed + bytes_consumed > subbuf_size) {
|
||||
relay_subbufs_consumed(buf->chan, buf->cpu, 1);
|
||||
buf->bytes_consumed = 0;
|
||||
}
|
||||
|
||||
buf->bytes_consumed += bytes_consumed;
|
||||
read_subbuf = read_pos / buf->chan->subbuf_size;
|
||||
if (buf->bytes_consumed + buf->padding[read_subbuf] == subbuf_size) {
|
||||
if ((read_subbuf == buf->subbufs_produced % n_subbufs) &&
|
||||
(buf->offset == subbuf_size))
|
||||
return;
|
||||
relay_subbufs_consumed(buf->chan, buf->cpu, 1);
|
||||
buf->bytes_consumed = 0;
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_file_read_avail - boolean, are there unconsumed bytes available?
|
||||
*/
|
||||
static int relay_file_read_avail(struct rchan_buf *buf, size_t read_pos)
|
||||
{
|
||||
size_t bytes_produced, bytes_consumed, write_offset;
|
||||
size_t subbuf_size = buf->chan->subbuf_size;
|
||||
size_t n_subbufs = buf->chan->n_subbufs;
|
||||
size_t produced = buf->subbufs_produced % n_subbufs;
|
||||
size_t consumed = buf->subbufs_consumed % n_subbufs;
|
||||
|
||||
write_offset = buf->offset > subbuf_size ? subbuf_size : buf->offset;
|
||||
|
||||
if (consumed > produced) {
|
||||
if ((produced > n_subbufs) &&
|
||||
(produced + n_subbufs - consumed <= n_subbufs))
|
||||
produced += n_subbufs;
|
||||
} else if (consumed == produced) {
|
||||
if (buf->offset > subbuf_size) {
|
||||
produced += n_subbufs;
|
||||
if (buf->subbufs_produced == buf->subbufs_consumed)
|
||||
consumed += n_subbufs;
|
||||
}
|
||||
}
|
||||
|
||||
if (buf->offset > subbuf_size)
|
||||
bytes_produced = (produced - 1) * subbuf_size + write_offset;
|
||||
else
|
||||
bytes_produced = produced * subbuf_size + write_offset;
|
||||
bytes_consumed = consumed * subbuf_size + buf->bytes_consumed;
|
||||
|
||||
if (bytes_produced == bytes_consumed)
|
||||
return 0;
|
||||
|
||||
relay_file_read_consume(buf, read_pos, 0);
|
||||
|
||||
return 1;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_file_read_subbuf_avail - return bytes available in sub-buffer
|
||||
*/
|
||||
static size_t relay_file_read_subbuf_avail(size_t read_pos,
|
||||
struct rchan_buf *buf)
|
||||
{
|
||||
size_t padding, avail = 0;
|
||||
size_t read_subbuf, read_offset, write_subbuf, write_offset;
|
||||
size_t subbuf_size = buf->chan->subbuf_size;
|
||||
|
||||
write_subbuf = (buf->data - buf->start) / subbuf_size;
|
||||
write_offset = buf->offset > subbuf_size ? subbuf_size : buf->offset;
|
||||
read_subbuf = read_pos / subbuf_size;
|
||||
read_offset = read_pos % subbuf_size;
|
||||
padding = buf->padding[read_subbuf];
|
||||
|
||||
if (read_subbuf == write_subbuf) {
|
||||
if (read_offset + padding < write_offset)
|
||||
avail = write_offset - (read_offset + padding);
|
||||
} else
|
||||
avail = (subbuf_size - padding) - read_offset;
|
||||
|
||||
return avail;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_file_read_start_pos - find the first available byte to read
|
||||
*
|
||||
* If the read_pos is in the middle of padding, return the
|
||||
* position of the first actually available byte, otherwise
|
||||
* return the original value.
|
||||
*/
|
||||
static size_t relay_file_read_start_pos(size_t read_pos,
|
||||
struct rchan_buf *buf)
|
||||
{
|
||||
size_t read_subbuf, padding, padding_start, padding_end;
|
||||
size_t subbuf_size = buf->chan->subbuf_size;
|
||||
size_t n_subbufs = buf->chan->n_subbufs;
|
||||
|
||||
read_subbuf = read_pos / subbuf_size;
|
||||
padding = buf->padding[read_subbuf];
|
||||
padding_start = (read_subbuf + 1) * subbuf_size - padding;
|
||||
padding_end = (read_subbuf + 1) * subbuf_size;
|
||||
if (read_pos >= padding_start && read_pos < padding_end) {
|
||||
read_subbuf = (read_subbuf + 1) % n_subbufs;
|
||||
read_pos = read_subbuf * subbuf_size;
|
||||
}
|
||||
|
||||
return read_pos;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_file_read_end_pos - return the new read position
|
||||
*/
|
||||
static size_t relay_file_read_end_pos(struct rchan_buf *buf,
|
||||
size_t read_pos,
|
||||
size_t count)
|
||||
{
|
||||
size_t read_subbuf, padding, end_pos;
|
||||
size_t subbuf_size = buf->chan->subbuf_size;
|
||||
size_t n_subbufs = buf->chan->n_subbufs;
|
||||
|
||||
read_subbuf = read_pos / subbuf_size;
|
||||
padding = buf->padding[read_subbuf];
|
||||
if (read_pos % subbuf_size + count + padding == subbuf_size)
|
||||
end_pos = (read_subbuf + 1) * subbuf_size;
|
||||
else
|
||||
end_pos = read_pos + count;
|
||||
if (end_pos >= subbuf_size * n_subbufs)
|
||||
end_pos = 0;
|
||||
|
||||
return end_pos;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_file_read - read file op for relay files
|
||||
* @filp: the file
|
||||
* @buffer: the userspace buffer
|
||||
* @count: number of bytes to read
|
||||
* @ppos: position to read from
|
||||
*
|
||||
* Reads count bytes or the number of bytes available in the
|
||||
* current sub-buffer being read, whichever is smaller.
|
||||
*/
|
||||
static ssize_t relay_file_read(struct file *filp,
|
||||
char __user *buffer,
|
||||
size_t count,
|
||||
loff_t *ppos)
|
||||
{
|
||||
struct rchan_buf *buf = filp->private_data;
|
||||
struct inode *inode = filp->f_dentry->d_inode;
|
||||
size_t read_start, avail;
|
||||
ssize_t ret = 0;
|
||||
void *from;
|
||||
|
||||
mutex_lock(&inode->i_mutex);
|
||||
if(!relay_file_read_avail(buf, *ppos))
|
||||
goto out;
|
||||
|
||||
read_start = relay_file_read_start_pos(*ppos, buf);
|
||||
avail = relay_file_read_subbuf_avail(read_start, buf);
|
||||
if (!avail)
|
||||
goto out;
|
||||
|
||||
from = buf->start + read_start;
|
||||
ret = count = min(count, avail);
|
||||
if (copy_to_user(buffer, from, count)) {
|
||||
ret = -EFAULT;
|
||||
goto out;
|
||||
}
|
||||
relay_file_read_consume(buf, read_start, count);
|
||||
*ppos = relay_file_read_end_pos(buf, read_start, count);
|
||||
out:
|
||||
mutex_unlock(&inode->i_mutex);
|
||||
return ret;
|
||||
}
|
||||
|
||||
struct file_operations relay_file_operations = {
|
||||
.open = relay_file_open,
|
||||
.poll = relay_file_poll,
|
||||
.mmap = relay_file_mmap,
|
||||
.read = relay_file_read,
|
||||
.llseek = no_llseek,
|
||||
.release = relay_file_release,
|
||||
};
|
||||
|
||||
static struct super_operations relayfs_ops = {
|
||||
.statfs = simple_statfs,
|
||||
.drop_inode = generic_delete_inode,
|
||||
};
|
||||
|
||||
static int relayfs_fill_super(struct super_block * sb, void * data, int silent)
|
||||
{
|
||||
struct inode *inode;
|
||||
struct dentry *root;
|
||||
int mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
|
||||
|
||||
sb->s_blocksize = PAGE_CACHE_SIZE;
|
||||
sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
|
||||
sb->s_magic = RELAYFS_MAGIC;
|
||||
sb->s_op = &relayfs_ops;
|
||||
inode = relayfs_get_inode(sb, mode, NULL, NULL);
|
||||
|
||||
if (!inode)
|
||||
return -ENOMEM;
|
||||
|
||||
root = d_alloc_root(inode);
|
||||
if (!root) {
|
||||
iput(inode);
|
||||
return -ENOMEM;
|
||||
}
|
||||
sb->s_root = root;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
static struct super_block * relayfs_get_sb(struct file_system_type *fs_type,
|
||||
int flags, const char *dev_name,
|
||||
void *data)
|
||||
{
|
||||
return get_sb_single(fs_type, flags, data, relayfs_fill_super);
|
||||
}
|
||||
|
||||
static struct file_system_type relayfs_fs_type = {
|
||||
.owner = THIS_MODULE,
|
||||
.name = "relayfs",
|
||||
.get_sb = relayfs_get_sb,
|
||||
.kill_sb = kill_litter_super,
|
||||
};
|
||||
|
||||
static int __init init_relayfs_fs(void)
|
||||
{
|
||||
return register_filesystem(&relayfs_fs_type);
|
||||
}
|
||||
|
||||
static void __exit exit_relayfs_fs(void)
|
||||
{
|
||||
|
||||
|
||||
|
||||
|
||||
|
||||
unregister_filesystem(&relayfs_fs_type);
|
||||
}
|
||||
|
||||
module_init(init_relayfs_fs)
|
||||
module_exit(exit_relayfs_fs)
|
||||
|
||||
EXPORT_SYMBOL_GPL(relay_file_operations);
|
||||
EXPORT_SYMBOL_GPL(relayfs_create_dir);
|
||||
EXPORT_SYMBOL_GPL(relayfs_remove_dir);
|
||||
EXPORT_SYMBOL_GPL(relayfs_create_file);
|
||||
EXPORT_SYMBOL_GPL(relayfs_remove_file);
|
||||
|
||||
MODULE_AUTHOR("Tom Zanussi <zanussi@us.ibm.com> and Karim Yaghmour <karim@opersys.com>");
|
||||
MODULE_DESCRIPTION("Relay Filesystem");
|
||||
MODULE_LICENSE("GPL");
|
||||
|
|
@ -1,482 +0,0 @@
|
|||
/*
|
||||
* Public API and common code for RelayFS.
|
||||
*
|
||||
* See Documentation/filesystems/relayfs.txt for an overview of relayfs.
|
||||
*
|
||||
* Copyright (C) 2002-2005 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp
|
||||
* Copyright (C) 1999-2005 - Karim Yaghmour (karim@opersys.com)
|
||||
*
|
||||
* This file is released under the GPL.
|
||||
*/
|
||||
|
||||
#include <linux/errno.h>
|
||||
#include <linux/stddef.h>
|
||||
#include <linux/slab.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/string.h>
|
||||
#include <linux/relayfs_fs.h>
|
||||
#include "relay.h"
|
||||
#include "buffers.h"
|
||||
|
||||
/**
|
||||
* relay_buf_empty - boolean, is the channel buffer empty?
|
||||
* @buf: channel buffer
|
||||
*
|
||||
* Returns 1 if the buffer is empty, 0 otherwise.
|
||||
*/
|
||||
int relay_buf_empty(struct rchan_buf *buf)
|
||||
{
|
||||
return (buf->subbufs_produced - buf->subbufs_consumed) ? 0 : 1;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_buf_full - boolean, is the channel buffer full?
|
||||
* @buf: channel buffer
|
||||
*
|
||||
* Returns 1 if the buffer is full, 0 otherwise.
|
||||
*/
|
||||
int relay_buf_full(struct rchan_buf *buf)
|
||||
{
|
||||
size_t ready = buf->subbufs_produced - buf->subbufs_consumed;
|
||||
return (ready >= buf->chan->n_subbufs) ? 1 : 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* High-level relayfs kernel API and associated functions.
|
||||
*/
|
||||
|
||||
/*
|
||||
* rchan_callback implementations defining default channel behavior. Used
|
||||
* in place of corresponding NULL values in client callback struct.
|
||||
*/
|
||||
|
||||
/*
|
||||
* subbuf_start() default callback. Does nothing.
|
||||
*/
|
||||
static int subbuf_start_default_callback (struct rchan_buf *buf,
|
||||
void *subbuf,
|
||||
void *prev_subbuf,
|
||||
size_t prev_padding)
|
||||
{
|
||||
if (relay_buf_full(buf))
|
||||
return 0;
|
||||
|
||||
return 1;
|
||||
}
|
||||
|
||||
/*
|
||||
* buf_mapped() default callback. Does nothing.
|
||||
*/
|
||||
static void buf_mapped_default_callback(struct rchan_buf *buf,
|
||||
struct file *filp)
|
||||
{
|
||||
}
|
||||
|
||||
/*
|
||||
* buf_unmapped() default callback. Does nothing.
|
||||
*/
|
||||
static void buf_unmapped_default_callback(struct rchan_buf *buf,
|
||||
struct file *filp)
|
||||
{
|
||||
}
|
||||
|
||||
/*
|
||||
* create_buf_file_create() default callback. Creates file to represent buf.
|
||||
*/
|
||||
static struct dentry *create_buf_file_default_callback(const char *filename,
|
||||
struct dentry *parent,
|
||||
int mode,
|
||||
struct rchan_buf *buf,
|
||||
int *is_global)
|
||||
{
|
||||
return relayfs_create_file(filename, parent, mode,
|
||||
&relay_file_operations, buf);
|
||||
}
|
||||
|
||||
/*
|
||||
* remove_buf_file() default callback. Removes file representing relay buffer.
|
||||
*/
|
||||
static int remove_buf_file_default_callback(struct dentry *dentry)
|
||||
{
|
||||
return relayfs_remove(dentry);
|
||||
}
|
||||
|
||||
/* relay channel default callbacks */
|
||||
static struct rchan_callbacks default_channel_callbacks = {
|
||||
.subbuf_start = subbuf_start_default_callback,
|
||||
.buf_mapped = buf_mapped_default_callback,
|
||||
.buf_unmapped = buf_unmapped_default_callback,
|
||||
.create_buf_file = create_buf_file_default_callback,
|
||||
.remove_buf_file = remove_buf_file_default_callback,
|
||||
};
|
||||
|
||||
/**
|
||||
* wakeup_readers - wake up readers waiting on a channel
|
||||
* @private: the channel buffer
|
||||
*
|
||||
* This is the work function used to defer reader waking. The
|
||||
* reason waking is deferred is that calling directly from write
|
||||
* causes problems if you're writing from say the scheduler.
|
||||
*/
|
||||
static void wakeup_readers(void *private)
|
||||
{
|
||||
struct rchan_buf *buf = private;
|
||||
wake_up_interruptible(&buf->read_wait);
|
||||
}
|
||||
|
||||
/**
|
||||
* __relay_reset - reset a channel buffer
|
||||
* @buf: the channel buffer
|
||||
* @init: 1 if this is a first-time initialization
|
||||
*
|
||||
* See relay_reset for description of effect.
|
||||
*/
|
||||
static inline void __relay_reset(struct rchan_buf *buf, unsigned int init)
|
||||
{
|
||||
size_t i;
|
||||
|
||||
if (init) {
|
||||
init_waitqueue_head(&buf->read_wait);
|
||||
kref_init(&buf->kref);
|
||||
INIT_WORK(&buf->wake_readers, NULL, NULL);
|
||||
} else {
|
||||
cancel_delayed_work(&buf->wake_readers);
|
||||
flush_scheduled_work();
|
||||
}
|
||||
|
||||
buf->subbufs_produced = 0;
|
||||
buf->subbufs_consumed = 0;
|
||||
buf->bytes_consumed = 0;
|
||||
buf->finalized = 0;
|
||||
buf->data = buf->start;
|
||||
buf->offset = 0;
|
||||
|
||||
for (i = 0; i < buf->chan->n_subbufs; i++)
|
||||
buf->padding[i] = 0;
|
||||
|
||||
buf->chan->cb->subbuf_start(buf, buf->data, NULL, 0);
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_reset - reset the channel
|
||||
* @chan: the channel
|
||||
*
|
||||
* This has the effect of erasing all data from all channel buffers
|
||||
* and restarting the channel in its initial state. The buffers
|
||||
* are not freed, so any mappings are still in effect.
|
||||
*
|
||||
* NOTE: Care should be taken that the channel isn't actually
|
||||
* being used by anything when this call is made.
|
||||
*/
|
||||
void relay_reset(struct rchan *chan)
|
||||
{
|
||||
unsigned int i;
|
||||
struct rchan_buf *prev = NULL;
|
||||
|
||||
if (!chan)
|
||||
return;
|
||||
|
||||
for (i = 0; i < NR_CPUS; i++) {
|
||||
if (!chan->buf[i] || chan->buf[i] == prev)
|
||||
break;
|
||||
__relay_reset(chan->buf[i], 0);
|
||||
prev = chan->buf[i];
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_open_buf - create a new channel buffer in relayfs
|
||||
*
|
||||
* Internal - used by relay_open().
|
||||
*/
|
||||
static struct rchan_buf *relay_open_buf(struct rchan *chan,
|
||||
const char *filename,
|
||||
struct dentry *parent,
|
||||
int *is_global)
|
||||
{
|
||||
struct rchan_buf *buf;
|
||||
struct dentry *dentry;
|
||||
|
||||
if (*is_global)
|
||||
return chan->buf[0];
|
||||
|
||||
buf = relay_create_buf(chan);
|
||||
if (!buf)
|
||||
return NULL;
|
||||
|
||||
/* Create file in fs */
|
||||
dentry = chan->cb->create_buf_file(filename, parent, S_IRUSR,
|
||||
buf, is_global);
|
||||
if (!dentry) {
|
||||
relay_destroy_buf(buf);
|
||||
return NULL;
|
||||
}
|
||||
|
||||
buf->dentry = dentry;
|
||||
__relay_reset(buf, 1);
|
||||
|
||||
return buf;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_close_buf - close a channel buffer
|
||||
* @buf: channel buffer
|
||||
*
|
||||
* Marks the buffer finalized and restores the default callbacks.
|
||||
* The channel buffer and channel buffer data structure are then freed
|
||||
* automatically when the last reference is given up.
|
||||
*/
|
||||
static inline void relay_close_buf(struct rchan_buf *buf)
|
||||
{
|
||||
buf->finalized = 1;
|
||||
buf->chan->cb = &default_channel_callbacks;
|
||||
cancel_delayed_work(&buf->wake_readers);
|
||||
flush_scheduled_work();
|
||||
kref_put(&buf->kref, relay_remove_buf);
|
||||
}
|
||||
|
||||
static inline void setup_callbacks(struct rchan *chan,
|
||||
struct rchan_callbacks *cb)
|
||||
{
|
||||
if (!cb) {
|
||||
chan->cb = &default_channel_callbacks;
|
||||
return;
|
||||
}
|
||||
|
||||
if (!cb->subbuf_start)
|
||||
cb->subbuf_start = subbuf_start_default_callback;
|
||||
if (!cb->buf_mapped)
|
||||
cb->buf_mapped = buf_mapped_default_callback;
|
||||
if (!cb->buf_unmapped)
|
||||
cb->buf_unmapped = buf_unmapped_default_callback;
|
||||
if (!cb->create_buf_file)
|
||||
cb->create_buf_file = create_buf_file_default_callback;
|
||||
if (!cb->remove_buf_file)
|
||||
cb->remove_buf_file = remove_buf_file_default_callback;
|
||||
chan->cb = cb;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_open - create a new relayfs channel
|
||||
* @base_filename: base name of files to create
|
||||
* @parent: dentry of parent directory, NULL for root directory
|
||||
* @subbuf_size: size of sub-buffers
|
||||
* @n_subbufs: number of sub-buffers
|
||||
* @cb: client callback functions
|
||||
*
|
||||
* Returns channel pointer if successful, NULL otherwise.
|
||||
*
|
||||
* Creates a channel buffer for each cpu using the sizes and
|
||||
* attributes specified. The created channel buffer files
|
||||
* will be named base_filename0...base_filenameN-1. File
|
||||
* permissions will be S_IRUSR.
|
||||
*/
|
||||
struct rchan *relay_open(const char *base_filename,
|
||||
struct dentry *parent,
|
||||
size_t subbuf_size,
|
||||
size_t n_subbufs,
|
||||
struct rchan_callbacks *cb)
|
||||
{
|
||||
unsigned int i;
|
||||
struct rchan *chan;
|
||||
char *tmpname;
|
||||
int is_global = 0;
|
||||
|
||||
if (!base_filename)
|
||||
return NULL;
|
||||
|
||||
if (!(subbuf_size && n_subbufs))
|
||||
return NULL;
|
||||
|
||||
chan = kcalloc(1, sizeof(struct rchan), GFP_KERNEL);
|
||||
if (!chan)
|
||||
return NULL;
|
||||
|
||||
chan->version = RELAYFS_CHANNEL_VERSION;
|
||||
chan->n_subbufs = n_subbufs;
|
||||
chan->subbuf_size = subbuf_size;
|
||||
chan->alloc_size = FIX_SIZE(subbuf_size * n_subbufs);
|
||||
setup_callbacks(chan, cb);
|
||||
kref_init(&chan->kref);
|
||||
|
||||
tmpname = kmalloc(NAME_MAX + 1, GFP_KERNEL);
|
||||
if (!tmpname)
|
||||
goto free_chan;
|
||||
|
||||
for_each_online_cpu(i) {
|
||||
sprintf(tmpname, "%s%d", base_filename, i);
|
||||
chan->buf[i] = relay_open_buf(chan, tmpname, parent,
|
||||
&is_global);
|
||||
chan->buf[i]->cpu = i;
|
||||
if (!chan->buf[i])
|
||||
goto free_bufs;
|
||||
}
|
||||
|
||||
kfree(tmpname);
|
||||
return chan;
|
||||
|
||||
free_bufs:
|
||||
for (i = 0; i < NR_CPUS; i++) {
|
||||
if (!chan->buf[i])
|
||||
break;
|
||||
relay_close_buf(chan->buf[i]);
|
||||
if (is_global)
|
||||
break;
|
||||
}
|
||||
kfree(tmpname);
|
||||
|
||||
free_chan:
|
||||
kref_put(&chan->kref, relay_destroy_channel);
|
||||
return NULL;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_switch_subbuf - switch to a new sub-buffer
|
||||
* @buf: channel buffer
|
||||
* @length: size of current event
|
||||
*
|
||||
* Returns either the length passed in or 0 if full.
|
||||
|
||||
* Performs sub-buffer-switch tasks such as invoking callbacks,
|
||||
* updating padding counts, waking up readers, etc.
|
||||
*/
|
||||
size_t relay_switch_subbuf(struct rchan_buf *buf, size_t length)
|
||||
{
|
||||
void *old, *new;
|
||||
size_t old_subbuf, new_subbuf;
|
||||
|
||||
if (unlikely(length > buf->chan->subbuf_size))
|
||||
goto toobig;
|
||||
|
||||
if (buf->offset != buf->chan->subbuf_size + 1) {
|
||||
buf->prev_padding = buf->chan->subbuf_size - buf->offset;
|
||||
old_subbuf = buf->subbufs_produced % buf->chan->n_subbufs;
|
||||
buf->padding[old_subbuf] = buf->prev_padding;
|
||||
buf->subbufs_produced++;
|
||||
if (waitqueue_active(&buf->read_wait)) {
|
||||
PREPARE_WORK(&buf->wake_readers, wakeup_readers, buf);
|
||||
schedule_delayed_work(&buf->wake_readers, 1);
|
||||
}
|
||||
}
|
||||
|
||||
old = buf->data;
|
||||
new_subbuf = buf->subbufs_produced % buf->chan->n_subbufs;
|
||||
new = buf->start + new_subbuf * buf->chan->subbuf_size;
|
||||
buf->offset = 0;
|
||||
if (!buf->chan->cb->subbuf_start(buf, new, old, buf->prev_padding)) {
|
||||
buf->offset = buf->chan->subbuf_size + 1;
|
||||
return 0;
|
||||
}
|
||||
buf->data = new;
|
||||
buf->padding[new_subbuf] = 0;
|
||||
|
||||
if (unlikely(length + buf->offset > buf->chan->subbuf_size))
|
||||
goto toobig;
|
||||
|
||||
return length;
|
||||
|
||||
toobig:
|
||||
buf->chan->last_toobig = length;
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_subbufs_consumed - update the buffer's sub-buffers-consumed count
|
||||
* @chan: the channel
|
||||
* @cpu: the cpu associated with the channel buffer to update
|
||||
* @subbufs_consumed: number of sub-buffers to add to current buf's count
|
||||
*
|
||||
* Adds to the channel buffer's consumed sub-buffer count.
|
||||
* subbufs_consumed should be the number of sub-buffers newly consumed,
|
||||
* not the total consumed.
|
||||
*
|
||||
* NOTE: kernel clients don't need to call this function if the channel
|
||||
* mode is 'overwrite'.
|
||||
*/
|
||||
void relay_subbufs_consumed(struct rchan *chan,
|
||||
unsigned int cpu,
|
||||
size_t subbufs_consumed)
|
||||
{
|
||||
struct rchan_buf *buf;
|
||||
|
||||
if (!chan)
|
||||
return;
|
||||
|
||||
if (cpu >= NR_CPUS || !chan->buf[cpu])
|
||||
return;
|
||||
|
||||
buf = chan->buf[cpu];
|
||||
buf->subbufs_consumed += subbufs_consumed;
|
||||
if (buf->subbufs_consumed > buf->subbufs_produced)
|
||||
buf->subbufs_consumed = buf->subbufs_produced;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_destroy_channel - free the channel struct
|
||||
*
|
||||
* Should only be called from kref_put().
|
||||
*/
|
||||
void relay_destroy_channel(struct kref *kref)
|
||||
{
|
||||
struct rchan *chan = container_of(kref, struct rchan, kref);
|
||||
kfree(chan);
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_close - close the channel
|
||||
* @chan: the channel
|
||||
*
|
||||
* Closes all channel buffers and frees the channel.
|
||||
*/
|
||||
void relay_close(struct rchan *chan)
|
||||
{
|
||||
unsigned int i;
|
||||
struct rchan_buf *prev = NULL;
|
||||
|
||||
if (!chan)
|
||||
return;
|
||||
|
||||
for (i = 0; i < NR_CPUS; i++) {
|
||||
if (!chan->buf[i] || chan->buf[i] == prev)
|
||||
break;
|
||||
relay_close_buf(chan->buf[i]);
|
||||
prev = chan->buf[i];
|
||||
}
|
||||
|
||||
if (chan->last_toobig)
|
||||
printk(KERN_WARNING "relayfs: one or more items not logged "
|
||||
"[item size (%Zd) > sub-buffer size (%Zd)]\n",
|
||||
chan->last_toobig, chan->subbuf_size);
|
||||
|
||||
kref_put(&chan->kref, relay_destroy_channel);
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_flush - close the channel
|
||||
* @chan: the channel
|
||||
*
|
||||
* Flushes all channel buffers i.e. forces buffer switch.
|
||||
*/
|
||||
void relay_flush(struct rchan *chan)
|
||||
{
|
||||
unsigned int i;
|
||||
struct rchan_buf *prev = NULL;
|
||||
|
||||
if (!chan)
|
||||
return;
|
||||
|
||||
for (i = 0; i < NR_CPUS; i++) {
|
||||
if (!chan->buf[i] || chan->buf[i] == prev)
|
||||
break;
|
||||
relay_switch_subbuf(chan->buf[i], 0);
|
||||
prev = chan->buf[i];
|
||||
}
|
||||
}
|
||||
|
||||
EXPORT_SYMBOL_GPL(relay_open);
|
||||
EXPORT_SYMBOL_GPL(relay_close);
|
||||
EXPORT_SYMBOL_GPL(relay_flush);
|
||||
EXPORT_SYMBOL_GPL(relay_reset);
|
||||
EXPORT_SYMBOL_GPL(relay_subbufs_consumed);
|
||||
EXPORT_SYMBOL_GPL(relay_switch_subbuf);
|
||||
EXPORT_SYMBOL_GPL(relay_buf_full);
|
|
@ -1,8 +0,0 @@
|
|||
#ifndef _RELAY_H
|
||||
#define _RELAY_H
|
||||
|
||||
extern int relayfs_remove(struct dentry *dentry);
|
||||
extern int relay_buf_empty(struct rchan_buf *buf);
|
||||
extern void relay_destroy_channel(struct kref *kref);
|
||||
|
||||
#endif /* _RELAY_H */
|
281
include/linux/relay.h
Normal file
281
include/linux/relay.h
Normal file
|
@ -0,0 +1,281 @@
|
|||
/*
|
||||
* linux/include/linux/relay.h
|
||||
*
|
||||
* Copyright (C) 2002, 2003 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp
|
||||
* Copyright (C) 1999, 2000, 2001, 2002 - Karim Yaghmour (karim@opersys.com)
|
||||
*
|
||||
* CONFIG_RELAY definitions and declarations
|
||||
*/
|
||||
|
||||
#ifndef _LINUX_RELAY_H
|
||||
#define _LINUX_RELAY_H
|
||||
|
||||
#include <linux/config.h>
|
||||
#include <linux/types.h>
|
||||
#include <linux/sched.h>
|
||||
#include <linux/wait.h>
|
||||
#include <linux/list.h>
|
||||
#include <linux/fs.h>
|
||||
#include <linux/poll.h>
|
||||
#include <linux/kref.h>
|
||||
|
||||
/* Needs a _much_ better name... */
|
||||
#define FIX_SIZE(x) ((((x) - 1) & PAGE_MASK) + PAGE_SIZE)
|
||||
|
||||
/*
|
||||
* Tracks changes to rchan/rchan_buf structs
|
||||
*/
|
||||
#define RELAYFS_CHANNEL_VERSION 6
|
||||
|
||||
/*
|
||||
* Per-cpu relay channel buffer
|
||||
*/
|
||||
struct rchan_buf
|
||||
{
|
||||
void *start; /* start of channel buffer */
|
||||
void *data; /* start of current sub-buffer */
|
||||
size_t offset; /* current offset into sub-buffer */
|
||||
size_t subbufs_produced; /* count of sub-buffers produced */
|
||||
size_t subbufs_consumed; /* count of sub-buffers consumed */
|
||||
struct rchan *chan; /* associated channel */
|
||||
wait_queue_head_t read_wait; /* reader wait queue */
|
||||
struct work_struct wake_readers; /* reader wake-up work struct */
|
||||
struct dentry *dentry; /* channel file dentry */
|
||||
struct kref kref; /* channel buffer refcount */
|
||||
struct page **page_array; /* array of current buffer pages */
|
||||
unsigned int page_count; /* number of current buffer pages */
|
||||
unsigned int finalized; /* buffer has been finalized */
|
||||
size_t *padding; /* padding counts per sub-buffer */
|
||||
size_t prev_padding; /* temporary variable */
|
||||
size_t bytes_consumed; /* bytes consumed in cur read subbuf */
|
||||
unsigned int cpu; /* this buf's cpu */
|
||||
} ____cacheline_aligned;
|
||||
|
||||
/*
|
||||
* Relay channel data structure
|
||||
*/
|
||||
struct rchan
|
||||
{
|
||||
u32 version; /* the version of this struct */
|
||||
size_t subbuf_size; /* sub-buffer size */
|
||||
size_t n_subbufs; /* number of sub-buffers per buffer */
|
||||
size_t alloc_size; /* total buffer size allocated */
|
||||
struct rchan_callbacks *cb; /* client callbacks */
|
||||
struct kref kref; /* channel refcount */
|
||||
void *private_data; /* for user-defined data */
|
||||
size_t last_toobig; /* tried to log event > subbuf size */
|
||||
struct rchan_buf *buf[NR_CPUS]; /* per-cpu channel buffers */
|
||||
};
|
||||
|
||||
/*
|
||||
* Relay channel client callbacks
|
||||
*/
|
||||
struct rchan_callbacks
|
||||
{
|
||||
/*
|
||||
* subbuf_start - called on buffer-switch to a new sub-buffer
|
||||
* @buf: the channel buffer containing the new sub-buffer
|
||||
* @subbuf: the start of the new sub-buffer
|
||||
* @prev_subbuf: the start of the previous sub-buffer
|
||||
* @prev_padding: unused space at the end of previous sub-buffer
|
||||
*
|
||||
* The client should return 1 to continue logging, 0 to stop
|
||||
* logging.
|
||||
*
|
||||
* NOTE: subbuf_start will also be invoked when the buffer is
|
||||
* created, so that the first sub-buffer can be initialized
|
||||
* if necessary. In this case, prev_subbuf will be NULL.
|
||||
*
|
||||
* NOTE: the client can reserve bytes at the beginning of the new
|
||||
* sub-buffer by calling subbuf_start_reserve() in this callback.
|
||||
*/
|
||||
int (*subbuf_start) (struct rchan_buf *buf,
|
||||
void *subbuf,
|
||||
void *prev_subbuf,
|
||||
size_t prev_padding);
|
||||
|
||||
/*
|
||||
* buf_mapped - relay buffer mmap notification
|
||||
* @buf: the channel buffer
|
||||
* @filp: relay file pointer
|
||||
*
|
||||
* Called when a relay file is successfully mmapped
|
||||
*/
|
||||
void (*buf_mapped)(struct rchan_buf *buf,
|
||||
struct file *filp);
|
||||
|
||||
/*
|
||||
* buf_unmapped - relay buffer unmap notification
|
||||
* @buf: the channel buffer
|
||||
* @filp: relay file pointer
|
||||
*
|
||||
* Called when a relay file is successfully unmapped
|
||||
*/
|
||||
void (*buf_unmapped)(struct rchan_buf *buf,
|
||||
struct file *filp);
|
||||
/*
|
||||
* create_buf_file - create file to represent a relay channel buffer
|
||||
* @filename: the name of the file to create
|
||||
* @parent: the parent of the file to create
|
||||
* @mode: the mode of the file to create
|
||||
* @buf: the channel buffer
|
||||
* @is_global: outparam - set non-zero if the buffer should be global
|
||||
*
|
||||
* Called during relay_open(), once for each per-cpu buffer,
|
||||
* to allow the client to create a file to be used to
|
||||
* represent the corresponding channel buffer. If the file is
|
||||
* created outside of relay, the parent must also exist in
|
||||
* that filesystem.
|
||||
*
|
||||
* The callback should return the dentry of the file created
|
||||
* to represent the relay buffer.
|
||||
*
|
||||
* Setting the is_global outparam to a non-zero value will
|
||||
* cause relay_open() to create a single global buffer rather
|
||||
* than the default set of per-cpu buffers.
|
||||
*
|
||||
* See Documentation/filesystems/relayfs.txt for more info.
|
||||
*/
|
||||
struct dentry *(*create_buf_file)(const char *filename,
|
||||
struct dentry *parent,
|
||||
int mode,
|
||||
struct rchan_buf *buf,
|
||||
int *is_global);
|
||||
|
||||
/*
|
||||
* remove_buf_file - remove file representing a relay channel buffer
|
||||
* @dentry: the dentry of the file to remove
|
||||
*
|
||||
* Called during relay_close(), once for each per-cpu buffer,
|
||||
* to allow the client to remove a file used to represent a
|
||||
* channel buffer.
|
||||
*
|
||||
* The callback should return 0 if successful, negative if not.
|
||||
*/
|
||||
int (*remove_buf_file)(struct dentry *dentry);
|
||||
};
|
||||
|
||||
/*
|
||||
* CONFIG_RELAY kernel API, kernel/relay.c
|
||||
*/
|
||||
|
||||
struct rchan *relay_open(const char *base_filename,
|
||||
struct dentry *parent,
|
||||
size_t subbuf_size,
|
||||
size_t n_subbufs,
|
||||
struct rchan_callbacks *cb);
|
||||
extern void relay_close(struct rchan *chan);
|
||||
extern void relay_flush(struct rchan *chan);
|
||||
extern void relay_subbufs_consumed(struct rchan *chan,
|
||||
unsigned int cpu,
|
||||
size_t consumed);
|
||||
extern void relay_reset(struct rchan *chan);
|
||||
extern int relay_buf_full(struct rchan_buf *buf);
|
||||
|
||||
extern size_t relay_switch_subbuf(struct rchan_buf *buf,
|
||||
size_t length);
|
||||
|
||||
/**
|
||||
* relay_write - write data into the channel
|
||||
* @chan: relay channel
|
||||
* @data: data to be written
|
||||
* @length: number of bytes to write
|
||||
*
|
||||
* Writes data into the current cpu's channel buffer.
|
||||
*
|
||||
* Protects the buffer by disabling interrupts. Use this
|
||||
* if you might be logging from interrupt context. Try
|
||||
* __relay_write() if you know you won't be logging from
|
||||
* interrupt context.
|
||||
*/
|
||||
static inline void relay_write(struct rchan *chan,
|
||||
const void *data,
|
||||
size_t length)
|
||||
{
|
||||
unsigned long flags;
|
||||
struct rchan_buf *buf;
|
||||
|
||||
local_irq_save(flags);
|
||||
buf = chan->buf[smp_processor_id()];
|
||||
if (unlikely(buf->offset + length > chan->subbuf_size))
|
||||
length = relay_switch_subbuf(buf, length);
|
||||
memcpy(buf->data + buf->offset, data, length);
|
||||
buf->offset += length;
|
||||
local_irq_restore(flags);
|
||||
}
|
||||
|
||||
/**
|
||||
* __relay_write - write data into the channel
|
||||
* @chan: relay channel
|
||||
* @data: data to be written
|
||||
* @length: number of bytes to write
|
||||
*
|
||||
* Writes data into the current cpu's channel buffer.
|
||||
*
|
||||
* Protects the buffer by disabling preemption. Use
|
||||
* relay_write() if you might be logging from interrupt
|
||||
* context.
|
||||
*/
|
||||
static inline void __relay_write(struct rchan *chan,
|
||||
const void *data,
|
||||
size_t length)
|
||||
{
|
||||
struct rchan_buf *buf;
|
||||
|
||||
buf = chan->buf[get_cpu()];
|
||||
if (unlikely(buf->offset + length > buf->chan->subbuf_size))
|
||||
length = relay_switch_subbuf(buf, length);
|
||||
memcpy(buf->data + buf->offset, data, length);
|
||||
buf->offset += length;
|
||||
put_cpu();
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_reserve - reserve slot in channel buffer
|
||||
* @chan: relay channel
|
||||
* @length: number of bytes to reserve
|
||||
*
|
||||
* Returns pointer to reserved slot, NULL if full.
|
||||
*
|
||||
* Reserves a slot in the current cpu's channel buffer.
|
||||
* Does not protect the buffer at all - caller must provide
|
||||
* appropriate synchronization.
|
||||
*/
|
||||
static inline void *relay_reserve(struct rchan *chan, size_t length)
|
||||
{
|
||||
void *reserved;
|
||||
struct rchan_buf *buf = chan->buf[smp_processor_id()];
|
||||
|
||||
if (unlikely(buf->offset + length > buf->chan->subbuf_size)) {
|
||||
length = relay_switch_subbuf(buf, length);
|
||||
if (!length)
|
||||
return NULL;
|
||||
}
|
||||
reserved = buf->data + buf->offset;
|
||||
buf->offset += length;
|
||||
|
||||
return reserved;
|
||||
}
|
||||
|
||||
/**
|
||||
* subbuf_start_reserve - reserve bytes at the start of a sub-buffer
|
||||
* @buf: relay channel buffer
|
||||
* @length: number of bytes to reserve
|
||||
*
|
||||
* Helper function used to reserve bytes at the beginning of
|
||||
* a sub-buffer in the subbuf_start() callback.
|
||||
*/
|
||||
static inline void subbuf_start_reserve(struct rchan_buf *buf,
|
||||
size_t length)
|
||||
{
|
||||
BUG_ON(length >= buf->chan->subbuf_size - 1);
|
||||
buf->offset = length;
|
||||
}
|
||||
|
||||
/*
|
||||
* exported relay file operations, kernel/relay.c
|
||||
*/
|
||||
extern struct file_operations relay_file_operations;
|
||||
|
||||
#endif /* _LINUX_RELAY_H */
|
||||
|
11
init/Kconfig
11
init/Kconfig
|
@ -214,6 +214,17 @@ config CPUSETS
|
|||
|
||||
Say N if unsure.
|
||||
|
||||
config RELAY
|
||||
bool "Kernel->user space relay support (formerly relayfs)"
|
||||
help
|
||||
This option enables support for relay interface support in
|
||||
certain file systems (such as debugfs).
|
||||
It is designed to provide an efficient mechanism for tools and
|
||||
facilities to relay large amounts of data from kernel space to
|
||||
user space.
|
||||
|
||||
If unsure, say N.
|
||||
|
||||
source "usr/Kconfig"
|
||||
|
||||
config UID16
|
||||
|
|
|
@ -34,6 +34,7 @@ obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o
|
|||
obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
|
||||
obj-$(CONFIG_SECCOMP) += seccomp.o
|
||||
obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o
|
||||
obj-$(CONFIG_RELAY) += relay.o
|
||||
|
||||
ifneq ($(CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER),y)
|
||||
# According to Alan Modra <alan@linuxcare.com.au>, the -fno-omit-frame-pointer is
|
||||
|
|
919
kernel/relay.c
Normal file
919
kernel/relay.c
Normal file
|
@ -0,0 +1,919 @@
|
|||
/*
|
||||
* Public API and common code for kernel->userspace relay file support.
|
||||
*
|
||||
* See Documentation/filesystems/relayfs.txt for an overview of relayfs.
|
||||
*
|
||||
* Copyright (C) 2002-2005 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp
|
||||
* Copyright (C) 1999-2005 - Karim Yaghmour (karim@opersys.com)
|
||||
*
|
||||
* Moved to kernel/relay.c by Paul Mundt, 2006.
|
||||
*
|
||||
* This file is released under the GPL.
|
||||
*/
|
||||
#include <linux/errno.h>
|
||||
#include <linux/stddef.h>
|
||||
#include <linux/slab.h>
|
||||
#include <linux/module.h>
|
||||
#include <linux/string.h>
|
||||
#include <linux/relay.h>
|
||||
#include <linux/vmalloc.h>
|
||||
#include <linux/mm.h>
|
||||
|
||||
/*
|
||||
* close() vm_op implementation for relay file mapping.
|
||||
*/
|
||||
static void relay_file_mmap_close(struct vm_area_struct *vma)
|
||||
{
|
||||
struct rchan_buf *buf = vma->vm_private_data;
|
||||
buf->chan->cb->buf_unmapped(buf, vma->vm_file);
|
||||
}
|
||||
|
||||
/*
|
||||
* nopage() vm_op implementation for relay file mapping.
|
||||
*/
|
||||
static struct page *relay_buf_nopage(struct vm_area_struct *vma,
|
||||
unsigned long address,
|
||||
int *type)
|
||||
{
|
||||
struct page *page;
|
||||
struct rchan_buf *buf = vma->vm_private_data;
|
||||
unsigned long offset = address - vma->vm_start;
|
||||
|
||||
if (address > vma->vm_end)
|
||||
return NOPAGE_SIGBUS; /* Disallow mremap */
|
||||
if (!buf)
|
||||
return NOPAGE_OOM;
|
||||
|
||||
page = vmalloc_to_page(buf->start + offset);
|
||||
if (!page)
|
||||
return NOPAGE_OOM;
|
||||
get_page(page);
|
||||
|
||||
if (type)
|
||||
*type = VM_FAULT_MINOR;
|
||||
|
||||
return page;
|
||||
}
|
||||
|
||||
/*
|
||||
* vm_ops for relay file mappings.
|
||||
*/
|
||||
static struct vm_operations_struct relay_file_mmap_ops = {
|
||||
.nopage = relay_buf_nopage,
|
||||
.close = relay_file_mmap_close,
|
||||
};
|
||||
|
||||
/**
|
||||
* relay_mmap_buf: - mmap channel buffer to process address space
|
||||
* @buf: relay channel buffer
|
||||
* @vma: vm_area_struct describing memory to be mapped
|
||||
*
|
||||
* Returns 0 if ok, negative on error
|
||||
*
|
||||
* Caller should already have grabbed mmap_sem.
|
||||
*/
|
||||
int relay_mmap_buf(struct rchan_buf *buf, struct vm_area_struct *vma)
|
||||
{
|
||||
unsigned long length = vma->vm_end - vma->vm_start;
|
||||
struct file *filp = vma->vm_file;
|
||||
|
||||
if (!buf)
|
||||
return -EBADF;
|
||||
|
||||
if (length != (unsigned long)buf->chan->alloc_size)
|
||||
return -EINVAL;
|
||||
|
||||
vma->vm_ops = &relay_file_mmap_ops;
|
||||
vma->vm_private_data = buf;
|
||||
buf->chan->cb->buf_mapped(buf, filp);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_alloc_buf - allocate a channel buffer
|
||||
* @buf: the buffer struct
|
||||
* @size: total size of the buffer
|
||||
*
|
||||
* Returns a pointer to the resulting buffer, NULL if unsuccessful
|
||||
*/
|
||||
static void *relay_alloc_buf(struct rchan_buf *buf, unsigned long size)
|
||||
{
|
||||
void *mem;
|
||||
unsigned int i, j, n_pages;
|
||||
|
||||
size = PAGE_ALIGN(size);
|
||||
n_pages = size >> PAGE_SHIFT;
|
||||
|
||||
buf->page_array = kcalloc(n_pages, sizeof(struct page *), GFP_KERNEL);
|
||||
if (!buf->page_array)
|
||||
return NULL;
|
||||
|
||||
for (i = 0; i < n_pages; i++) {
|
||||
buf->page_array[i] = alloc_page(GFP_KERNEL);
|
||||
if (unlikely(!buf->page_array[i]))
|
||||
goto depopulate;
|
||||
}
|
||||
mem = vmap(buf->page_array, n_pages, VM_MAP, PAGE_KERNEL);
|
||||
if (!mem)
|
||||
goto depopulate;
|
||||
|
||||
memset(mem, 0, size);
|
||||
buf->page_count = n_pages;
|
||||
return mem;
|
||||
|
||||
depopulate:
|
||||
for (j = 0; j < i; j++)
|
||||
__free_page(buf->page_array[j]);
|
||||
kfree(buf->page_array);
|
||||
return NULL;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_create_buf - allocate and initialize a channel buffer
|
||||
* @alloc_size: size of the buffer to allocate
|
||||
* @n_subbufs: number of sub-buffers in the channel
|
||||
*
|
||||
* Returns channel buffer if successful, NULL otherwise
|
||||
*/
|
||||
struct rchan_buf *relay_create_buf(struct rchan *chan)
|
||||
{
|
||||
struct rchan_buf *buf = kcalloc(1, sizeof(struct rchan_buf), GFP_KERNEL);
|
||||
if (!buf)
|
||||
return NULL;
|
||||
|
||||
buf->padding = kmalloc(chan->n_subbufs * sizeof(size_t *), GFP_KERNEL);
|
||||
if (!buf->padding)
|
||||
goto free_buf;
|
||||
|
||||
buf->start = relay_alloc_buf(buf, chan->alloc_size);
|
||||
if (!buf->start)
|
||||
goto free_buf;
|
||||
|
||||
buf->chan = chan;
|
||||
kref_get(&buf->chan->kref);
|
||||
return buf;
|
||||
|
||||
free_buf:
|
||||
kfree(buf->padding);
|
||||
kfree(buf);
|
||||
return NULL;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_destroy_channel - free the channel struct
|
||||
*
|
||||
* Should only be called from kref_put().
|
||||
*/
|
||||
void relay_destroy_channel(struct kref *kref)
|
||||
{
|
||||
struct rchan *chan = container_of(kref, struct rchan, kref);
|
||||
kfree(chan);
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_destroy_buf - destroy an rchan_buf struct and associated buffer
|
||||
* @buf: the buffer struct
|
||||
*/
|
||||
void relay_destroy_buf(struct rchan_buf *buf)
|
||||
{
|
||||
struct rchan *chan = buf->chan;
|
||||
unsigned int i;
|
||||
|
||||
if (likely(buf->start)) {
|
||||
vunmap(buf->start);
|
||||
for (i = 0; i < buf->page_count; i++)
|
||||
__free_page(buf->page_array[i]);
|
||||
kfree(buf->page_array);
|
||||
}
|
||||
kfree(buf->padding);
|
||||
kfree(buf);
|
||||
kref_put(&chan->kref, relay_destroy_channel);
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_remove_buf - remove a channel buffer
|
||||
*
|
||||
* Removes the file from the fileystem, which also frees the
|
||||
* rchan_buf_struct and the channel buffer. Should only be called from
|
||||
* kref_put().
|
||||
*/
|
||||
void relay_remove_buf(struct kref *kref)
|
||||
{
|
||||
struct rchan_buf *buf = container_of(kref, struct rchan_buf, kref);
|
||||
buf->chan->cb->remove_buf_file(buf->dentry);
|
||||
relay_destroy_buf(buf);
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_buf_empty - boolean, is the channel buffer empty?
|
||||
* @buf: channel buffer
|
||||
*
|
||||
* Returns 1 if the buffer is empty, 0 otherwise.
|
||||
*/
|
||||
int relay_buf_empty(struct rchan_buf *buf)
|
||||
{
|
||||
return (buf->subbufs_produced - buf->subbufs_consumed) ? 0 : 1;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(relay_buf_empty);
|
||||
|
||||
/**
|
||||
* relay_buf_full - boolean, is the channel buffer full?
|
||||
* @buf: channel buffer
|
||||
*
|
||||
* Returns 1 if the buffer is full, 0 otherwise.
|
||||
*/
|
||||
int relay_buf_full(struct rchan_buf *buf)
|
||||
{
|
||||
size_t ready = buf->subbufs_produced - buf->subbufs_consumed;
|
||||
return (ready >= buf->chan->n_subbufs) ? 1 : 0;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(relay_buf_full);
|
||||
|
||||
/*
|
||||
* High-level relay kernel API and associated functions.
|
||||
*/
|
||||
|
||||
/*
|
||||
* rchan_callback implementations defining default channel behavior. Used
|
||||
* in place of corresponding NULL values in client callback struct.
|
||||
*/
|
||||
|
||||
/*
|
||||
* subbuf_start() default callback. Does nothing.
|
||||
*/
|
||||
static int subbuf_start_default_callback (struct rchan_buf *buf,
|
||||
void *subbuf,
|
||||
void *prev_subbuf,
|
||||
size_t prev_padding)
|
||||
{
|
||||
if (relay_buf_full(buf))
|
||||
return 0;
|
||||
|
||||
return 1;
|
||||
}
|
||||
|
||||
/*
|
||||
* buf_mapped() default callback. Does nothing.
|
||||
*/
|
||||
static void buf_mapped_default_callback(struct rchan_buf *buf,
|
||||
struct file *filp)
|
||||
{
|
||||
}
|
||||
|
||||
/*
|
||||
* buf_unmapped() default callback. Does nothing.
|
||||
*/
|
||||
static void buf_unmapped_default_callback(struct rchan_buf *buf,
|
||||
struct file *filp)
|
||||
{
|
||||
}
|
||||
|
||||
/*
|
||||
* create_buf_file_create() default callback. Does nothing.
|
||||
*/
|
||||
static struct dentry *create_buf_file_default_callback(const char *filename,
|
||||
struct dentry *parent,
|
||||
int mode,
|
||||
struct rchan_buf *buf,
|
||||
int *is_global)
|
||||
{
|
||||
return NULL;
|
||||
}
|
||||
|
||||
/*
|
||||
* remove_buf_file() default callback. Does nothing.
|
||||
*/
|
||||
static int remove_buf_file_default_callback(struct dentry *dentry)
|
||||
{
|
||||
return -EINVAL;
|
||||
}
|
||||
|
||||
/* relay channel default callbacks */
|
||||
static struct rchan_callbacks default_channel_callbacks = {
|
||||
.subbuf_start = subbuf_start_default_callback,
|
||||
.buf_mapped = buf_mapped_default_callback,
|
||||
.buf_unmapped = buf_unmapped_default_callback,
|
||||
.create_buf_file = create_buf_file_default_callback,
|
||||
.remove_buf_file = remove_buf_file_default_callback,
|
||||
};
|
||||
|
||||
/**
|
||||
* wakeup_readers - wake up readers waiting on a channel
|
||||
* @private: the channel buffer
|
||||
*
|
||||
* This is the work function used to defer reader waking. The
|
||||
* reason waking is deferred is that calling directly from write
|
||||
* causes problems if you're writing from say the scheduler.
|
||||
*/
|
||||
static void wakeup_readers(void *private)
|
||||
{
|
||||
struct rchan_buf *buf = private;
|
||||
wake_up_interruptible(&buf->read_wait);
|
||||
}
|
||||
|
||||
/**
|
||||
* __relay_reset - reset a channel buffer
|
||||
* @buf: the channel buffer
|
||||
* @init: 1 if this is a first-time initialization
|
||||
*
|
||||
* See relay_reset for description of effect.
|
||||
*/
|
||||
static inline void __relay_reset(struct rchan_buf *buf, unsigned int init)
|
||||
{
|
||||
size_t i;
|
||||
|
||||
if (init) {
|
||||
init_waitqueue_head(&buf->read_wait);
|
||||
kref_init(&buf->kref);
|
||||
INIT_WORK(&buf->wake_readers, NULL, NULL);
|
||||
} else {
|
||||
cancel_delayed_work(&buf->wake_readers);
|
||||
flush_scheduled_work();
|
||||
}
|
||||
|
||||
buf->subbufs_produced = 0;
|
||||
buf->subbufs_consumed = 0;
|
||||
buf->bytes_consumed = 0;
|
||||
buf->finalized = 0;
|
||||
buf->data = buf->start;
|
||||
buf->offset = 0;
|
||||
|
||||
for (i = 0; i < buf->chan->n_subbufs; i++)
|
||||
buf->padding[i] = 0;
|
||||
|
||||
buf->chan->cb->subbuf_start(buf, buf->data, NULL, 0);
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_reset - reset the channel
|
||||
* @chan: the channel
|
||||
*
|
||||
* This has the effect of erasing all data from all channel buffers
|
||||
* and restarting the channel in its initial state. The buffers
|
||||
* are not freed, so any mappings are still in effect.
|
||||
*
|
||||
* NOTE: Care should be taken that the channel isn't actually
|
||||
* being used by anything when this call is made.
|
||||
*/
|
||||
void relay_reset(struct rchan *chan)
|
||||
{
|
||||
unsigned int i;
|
||||
struct rchan_buf *prev = NULL;
|
||||
|
||||
if (!chan)
|
||||
return;
|
||||
|
||||
for (i = 0; i < NR_CPUS; i++) {
|
||||
if (!chan->buf[i] || chan->buf[i] == prev)
|
||||
break;
|
||||
__relay_reset(chan->buf[i], 0);
|
||||
prev = chan->buf[i];
|
||||
}
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(relay_reset);
|
||||
|
||||
/**
|
||||
* relay_open_buf - create a new relay channel buffer
|
||||
*
|
||||
* Internal - used by relay_open().
|
||||
*/
|
||||
static struct rchan_buf *relay_open_buf(struct rchan *chan,
|
||||
const char *filename,
|
||||
struct dentry *parent,
|
||||
int *is_global)
|
||||
{
|
||||
struct rchan_buf *buf;
|
||||
struct dentry *dentry;
|
||||
|
||||
if (*is_global)
|
||||
return chan->buf[0];
|
||||
|
||||
buf = relay_create_buf(chan);
|
||||
if (!buf)
|
||||
return NULL;
|
||||
|
||||
/* Create file in fs */
|
||||
dentry = chan->cb->create_buf_file(filename, parent, S_IRUSR,
|
||||
buf, is_global);
|
||||
if (!dentry) {
|
||||
relay_destroy_buf(buf);
|
||||
return NULL;
|
||||
}
|
||||
|
||||
buf->dentry = dentry;
|
||||
__relay_reset(buf, 1);
|
||||
|
||||
return buf;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_close_buf - close a channel buffer
|
||||
* @buf: channel buffer
|
||||
*
|
||||
* Marks the buffer finalized and restores the default callbacks.
|
||||
* The channel buffer and channel buffer data structure are then freed
|
||||
* automatically when the last reference is given up.
|
||||
*/
|
||||
static inline void relay_close_buf(struct rchan_buf *buf)
|
||||
{
|
||||
buf->finalized = 1;
|
||||
cancel_delayed_work(&buf->wake_readers);
|
||||
flush_scheduled_work();
|
||||
kref_put(&buf->kref, relay_remove_buf);
|
||||
}
|
||||
|
||||
static inline void setup_callbacks(struct rchan *chan,
|
||||
struct rchan_callbacks *cb)
|
||||
{
|
||||
if (!cb) {
|
||||
chan->cb = &default_channel_callbacks;
|
||||
return;
|
||||
}
|
||||
|
||||
if (!cb->subbuf_start)
|
||||
cb->subbuf_start = subbuf_start_default_callback;
|
||||
if (!cb->buf_mapped)
|
||||
cb->buf_mapped = buf_mapped_default_callback;
|
||||
if (!cb->buf_unmapped)
|
||||
cb->buf_unmapped = buf_unmapped_default_callback;
|
||||
if (!cb->create_buf_file)
|
||||
cb->create_buf_file = create_buf_file_default_callback;
|
||||
if (!cb->remove_buf_file)
|
||||
cb->remove_buf_file = remove_buf_file_default_callback;
|
||||
chan->cb = cb;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_open - create a new relay channel
|
||||
* @base_filename: base name of files to create
|
||||
* @parent: dentry of parent directory, NULL for root directory
|
||||
* @subbuf_size: size of sub-buffers
|
||||
* @n_subbufs: number of sub-buffers
|
||||
* @cb: client callback functions
|
||||
*
|
||||
* Returns channel pointer if successful, NULL otherwise.
|
||||
*
|
||||
* Creates a channel buffer for each cpu using the sizes and
|
||||
* attributes specified. The created channel buffer files
|
||||
* will be named base_filename0...base_filenameN-1. File
|
||||
* permissions will be S_IRUSR.
|
||||
*/
|
||||
struct rchan *relay_open(const char *base_filename,
|
||||
struct dentry *parent,
|
||||
size_t subbuf_size,
|
||||
size_t n_subbufs,
|
||||
struct rchan_callbacks *cb)
|
||||
{
|
||||
unsigned int i;
|
||||
struct rchan *chan;
|
||||
char *tmpname;
|
||||
int is_global = 0;
|
||||
|
||||
if (!base_filename)
|
||||
return NULL;
|
||||
|
||||
if (!(subbuf_size && n_subbufs))
|
||||
return NULL;
|
||||
|
||||
chan = kcalloc(1, sizeof(struct rchan), GFP_KERNEL);
|
||||
if (!chan)
|
||||
return NULL;
|
||||
|
||||
chan->version = RELAYFS_CHANNEL_VERSION;
|
||||
chan->n_subbufs = n_subbufs;
|
||||
chan->subbuf_size = subbuf_size;
|
||||
chan->alloc_size = FIX_SIZE(subbuf_size * n_subbufs);
|
||||
setup_callbacks(chan, cb);
|
||||
kref_init(&chan->kref);
|
||||
|
||||
tmpname = kmalloc(NAME_MAX + 1, GFP_KERNEL);
|
||||
if (!tmpname)
|
||||
goto free_chan;
|
||||
|
||||
for_each_online_cpu(i) {
|
||||
sprintf(tmpname, "%s%d", base_filename, i);
|
||||
chan->buf[i] = relay_open_buf(chan, tmpname, parent,
|
||||
&is_global);
|
||||
if (!chan->buf[i])
|
||||
goto free_bufs;
|
||||
|
||||
chan->buf[i]->cpu = i;
|
||||
}
|
||||
|
||||
kfree(tmpname);
|
||||
return chan;
|
||||
|
||||
free_bufs:
|
||||
for (i = 0; i < NR_CPUS; i++) {
|
||||
if (!chan->buf[i])
|
||||
break;
|
||||
relay_close_buf(chan->buf[i]);
|
||||
if (is_global)
|
||||
break;
|
||||
}
|
||||
kfree(tmpname);
|
||||
|
||||
free_chan:
|
||||
kref_put(&chan->kref, relay_destroy_channel);
|
||||
return NULL;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(relay_open);
|
||||
|
||||
/**
|
||||
* relay_switch_subbuf - switch to a new sub-buffer
|
||||
* @buf: channel buffer
|
||||
* @length: size of current event
|
||||
*
|
||||
* Returns either the length passed in or 0 if full.
|
||||
*
|
||||
* Performs sub-buffer-switch tasks such as invoking callbacks,
|
||||
* updating padding counts, waking up readers, etc.
|
||||
*/
|
||||
size_t relay_switch_subbuf(struct rchan_buf *buf, size_t length)
|
||||
{
|
||||
void *old, *new;
|
||||
size_t old_subbuf, new_subbuf;
|
||||
|
||||
if (unlikely(length > buf->chan->subbuf_size))
|
||||
goto toobig;
|
||||
|
||||
if (buf->offset != buf->chan->subbuf_size + 1) {
|
||||
buf->prev_padding = buf->chan->subbuf_size - buf->offset;
|
||||
old_subbuf = buf->subbufs_produced % buf->chan->n_subbufs;
|
||||
buf->padding[old_subbuf] = buf->prev_padding;
|
||||
buf->subbufs_produced++;
|
||||
if (waitqueue_active(&buf->read_wait)) {
|
||||
PREPARE_WORK(&buf->wake_readers, wakeup_readers, buf);
|
||||
schedule_delayed_work(&buf->wake_readers, 1);
|
||||
}
|
||||
}
|
||||
|
||||
old = buf->data;
|
||||
new_subbuf = buf->subbufs_produced % buf->chan->n_subbufs;
|
||||
new = buf->start + new_subbuf * buf->chan->subbuf_size;
|
||||
buf->offset = 0;
|
||||
if (!buf->chan->cb->subbuf_start(buf, new, old, buf->prev_padding)) {
|
||||
buf->offset = buf->chan->subbuf_size + 1;
|
||||
return 0;
|
||||
}
|
||||
buf->data = new;
|
||||
buf->padding[new_subbuf] = 0;
|
||||
|
||||
if (unlikely(length + buf->offset > buf->chan->subbuf_size))
|
||||
goto toobig;
|
||||
|
||||
return length;
|
||||
|
||||
toobig:
|
||||
buf->chan->last_toobig = length;
|
||||
return 0;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(relay_switch_subbuf);
|
||||
|
||||
/**
|
||||
* relay_subbufs_consumed - update the buffer's sub-buffers-consumed count
|
||||
* @chan: the channel
|
||||
* @cpu: the cpu associated with the channel buffer to update
|
||||
* @subbufs_consumed: number of sub-buffers to add to current buf's count
|
||||
*
|
||||
* Adds to the channel buffer's consumed sub-buffer count.
|
||||
* subbufs_consumed should be the number of sub-buffers newly consumed,
|
||||
* not the total consumed.
|
||||
*
|
||||
* NOTE: kernel clients don't need to call this function if the channel
|
||||
* mode is 'overwrite'.
|
||||
*/
|
||||
void relay_subbufs_consumed(struct rchan *chan,
|
||||
unsigned int cpu,
|
||||
size_t subbufs_consumed)
|
||||
{
|
||||
struct rchan_buf *buf;
|
||||
|
||||
if (!chan)
|
||||
return;
|
||||
|
||||
if (cpu >= NR_CPUS || !chan->buf[cpu])
|
||||
return;
|
||||
|
||||
buf = chan->buf[cpu];
|
||||
buf->subbufs_consumed += subbufs_consumed;
|
||||
if (buf->subbufs_consumed > buf->subbufs_produced)
|
||||
buf->subbufs_consumed = buf->subbufs_produced;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(relay_subbufs_consumed);
|
||||
|
||||
/**
|
||||
* relay_close - close the channel
|
||||
* @chan: the channel
|
||||
*
|
||||
* Closes all channel buffers and frees the channel.
|
||||
*/
|
||||
void relay_close(struct rchan *chan)
|
||||
{
|
||||
unsigned int i;
|
||||
struct rchan_buf *prev = NULL;
|
||||
|
||||
if (!chan)
|
||||
return;
|
||||
|
||||
for (i = 0; i < NR_CPUS; i++) {
|
||||
if (!chan->buf[i] || chan->buf[i] == prev)
|
||||
break;
|
||||
relay_close_buf(chan->buf[i]);
|
||||
prev = chan->buf[i];
|
||||
}
|
||||
|
||||
if (chan->last_toobig)
|
||||
printk(KERN_WARNING "relay: one or more items not logged "
|
||||
"[item size (%Zd) > sub-buffer size (%Zd)]\n",
|
||||
chan->last_toobig, chan->subbuf_size);
|
||||
|
||||
kref_put(&chan->kref, relay_destroy_channel);
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(relay_close);
|
||||
|
||||
/**
|
||||
* relay_flush - close the channel
|
||||
* @chan: the channel
|
||||
*
|
||||
* Flushes all channel buffers i.e. forces buffer switch.
|
||||
*/
|
||||
void relay_flush(struct rchan *chan)
|
||||
{
|
||||
unsigned int i;
|
||||
struct rchan_buf *prev = NULL;
|
||||
|
||||
if (!chan)
|
||||
return;
|
||||
|
||||
for (i = 0; i < NR_CPUS; i++) {
|
||||
if (!chan->buf[i] || chan->buf[i] == prev)
|
||||
break;
|
||||
relay_switch_subbuf(chan->buf[i], 0);
|
||||
prev = chan->buf[i];
|
||||
}
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(relay_flush);
|
||||
|
||||
/**
|
||||
* relay_file_open - open file op for relay files
|
||||
* @inode: the inode
|
||||
* @filp: the file
|
||||
*
|
||||
* Increments the channel buffer refcount.
|
||||
*/
|
||||
static int relay_file_open(struct inode *inode, struct file *filp)
|
||||
{
|
||||
struct rchan_buf *buf = inode->u.generic_ip;
|
||||
kref_get(&buf->kref);
|
||||
filp->private_data = buf;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_file_mmap - mmap file op for relay files
|
||||
* @filp: the file
|
||||
* @vma: the vma describing what to map
|
||||
*
|
||||
* Calls upon relay_mmap_buf to map the file into user space.
|
||||
*/
|
||||
static int relay_file_mmap(struct file *filp, struct vm_area_struct *vma)
|
||||
{
|
||||
struct rchan_buf *buf = filp->private_data;
|
||||
return relay_mmap_buf(buf, vma);
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_file_poll - poll file op for relay files
|
||||
* @filp: the file
|
||||
* @wait: poll table
|
||||
*
|
||||
* Poll implemention.
|
||||
*/
|
||||
static unsigned int relay_file_poll(struct file *filp, poll_table *wait)
|
||||
{
|
||||
unsigned int mask = 0;
|
||||
struct rchan_buf *buf = filp->private_data;
|
||||
|
||||
if (buf->finalized)
|
||||
return POLLERR;
|
||||
|
||||
if (filp->f_mode & FMODE_READ) {
|
||||
poll_wait(filp, &buf->read_wait, wait);
|
||||
if (!relay_buf_empty(buf))
|
||||
mask |= POLLIN | POLLRDNORM;
|
||||
}
|
||||
|
||||
return mask;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_file_release - release file op for relay files
|
||||
* @inode: the inode
|
||||
* @filp: the file
|
||||
*
|
||||
* Decrements the channel refcount, as the filesystem is
|
||||
* no longer using it.
|
||||
*/
|
||||
static int relay_file_release(struct inode *inode, struct file *filp)
|
||||
{
|
||||
struct rchan_buf *buf = filp->private_data;
|
||||
kref_put(&buf->kref, relay_remove_buf);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_file_read_consume - update the consumed count for the buffer
|
||||
*/
|
||||
static void relay_file_read_consume(struct rchan_buf *buf,
|
||||
size_t read_pos,
|
||||
size_t bytes_consumed)
|
||||
{
|
||||
size_t subbuf_size = buf->chan->subbuf_size;
|
||||
size_t n_subbufs = buf->chan->n_subbufs;
|
||||
size_t read_subbuf;
|
||||
|
||||
if (buf->bytes_consumed + bytes_consumed > subbuf_size) {
|
||||
relay_subbufs_consumed(buf->chan, buf->cpu, 1);
|
||||
buf->bytes_consumed = 0;
|
||||
}
|
||||
|
||||
buf->bytes_consumed += bytes_consumed;
|
||||
read_subbuf = read_pos / buf->chan->subbuf_size;
|
||||
if (buf->bytes_consumed + buf->padding[read_subbuf] == subbuf_size) {
|
||||
if ((read_subbuf == buf->subbufs_produced % n_subbufs) &&
|
||||
(buf->offset == subbuf_size))
|
||||
return;
|
||||
relay_subbufs_consumed(buf->chan, buf->cpu, 1);
|
||||
buf->bytes_consumed = 0;
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_file_read_avail - boolean, are there unconsumed bytes available?
|
||||
*/
|
||||
static int relay_file_read_avail(struct rchan_buf *buf, size_t read_pos)
|
||||
{
|
||||
size_t bytes_produced, bytes_consumed, write_offset;
|
||||
size_t subbuf_size = buf->chan->subbuf_size;
|
||||
size_t n_subbufs = buf->chan->n_subbufs;
|
||||
size_t produced = buf->subbufs_produced % n_subbufs;
|
||||
size_t consumed = buf->subbufs_consumed % n_subbufs;
|
||||
|
||||
write_offset = buf->offset > subbuf_size ? subbuf_size : buf->offset;
|
||||
|
||||
if (consumed > produced) {
|
||||
if ((produced > n_subbufs) &&
|
||||
(produced + n_subbufs - consumed <= n_subbufs))
|
||||
produced += n_subbufs;
|
||||
} else if (consumed == produced) {
|
||||
if (buf->offset > subbuf_size) {
|
||||
produced += n_subbufs;
|
||||
if (buf->subbufs_produced == buf->subbufs_consumed)
|
||||
consumed += n_subbufs;
|
||||
}
|
||||
}
|
||||
|
||||
if (buf->offset > subbuf_size)
|
||||
bytes_produced = (produced - 1) * subbuf_size + write_offset;
|
||||
else
|
||||
bytes_produced = produced * subbuf_size + write_offset;
|
||||
bytes_consumed = consumed * subbuf_size + buf->bytes_consumed;
|
||||
|
||||
if (bytes_produced == bytes_consumed)
|
||||
return 0;
|
||||
|
||||
relay_file_read_consume(buf, read_pos, 0);
|
||||
|
||||
return 1;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_file_read_subbuf_avail - return bytes available in sub-buffer
|
||||
*/
|
||||
static size_t relay_file_read_subbuf_avail(size_t read_pos,
|
||||
struct rchan_buf *buf)
|
||||
{
|
||||
size_t padding, avail = 0;
|
||||
size_t read_subbuf, read_offset, write_subbuf, write_offset;
|
||||
size_t subbuf_size = buf->chan->subbuf_size;
|
||||
|
||||
write_subbuf = (buf->data - buf->start) / subbuf_size;
|
||||
write_offset = buf->offset > subbuf_size ? subbuf_size : buf->offset;
|
||||
read_subbuf = read_pos / subbuf_size;
|
||||
read_offset = read_pos % subbuf_size;
|
||||
padding = buf->padding[read_subbuf];
|
||||
|
||||
if (read_subbuf == write_subbuf) {
|
||||
if (read_offset + padding < write_offset)
|
||||
avail = write_offset - (read_offset + padding);
|
||||
} else
|
||||
avail = (subbuf_size - padding) - read_offset;
|
||||
|
||||
return avail;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_file_read_start_pos - find the first available byte to read
|
||||
*
|
||||
* If the read_pos is in the middle of padding, return the
|
||||
* position of the first actually available byte, otherwise
|
||||
* return the original value.
|
||||
*/
|
||||
static size_t relay_file_read_start_pos(size_t read_pos,
|
||||
struct rchan_buf *buf)
|
||||
{
|
||||
size_t read_subbuf, padding, padding_start, padding_end;
|
||||
size_t subbuf_size = buf->chan->subbuf_size;
|
||||
size_t n_subbufs = buf->chan->n_subbufs;
|
||||
|
||||
read_subbuf = read_pos / subbuf_size;
|
||||
padding = buf->padding[read_subbuf];
|
||||
padding_start = (read_subbuf + 1) * subbuf_size - padding;
|
||||
padding_end = (read_subbuf + 1) * subbuf_size;
|
||||
if (read_pos >= padding_start && read_pos < padding_end) {
|
||||
read_subbuf = (read_subbuf + 1) % n_subbufs;
|
||||
read_pos = read_subbuf * subbuf_size;
|
||||
}
|
||||
|
||||
return read_pos;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_file_read_end_pos - return the new read position
|
||||
*/
|
||||
static size_t relay_file_read_end_pos(struct rchan_buf *buf,
|
||||
size_t read_pos,
|
||||
size_t count)
|
||||
{
|
||||
size_t read_subbuf, padding, end_pos;
|
||||
size_t subbuf_size = buf->chan->subbuf_size;
|
||||
size_t n_subbufs = buf->chan->n_subbufs;
|
||||
|
||||
read_subbuf = read_pos / subbuf_size;
|
||||
padding = buf->padding[read_subbuf];
|
||||
if (read_pos % subbuf_size + count + padding == subbuf_size)
|
||||
end_pos = (read_subbuf + 1) * subbuf_size;
|
||||
else
|
||||
end_pos = read_pos + count;
|
||||
if (end_pos >= subbuf_size * n_subbufs)
|
||||
end_pos = 0;
|
||||
|
||||
return end_pos;
|
||||
}
|
||||
|
||||
/**
|
||||
* relay_file_read - read file op for relay files
|
||||
* @filp: the file
|
||||
* @buffer: the userspace buffer
|
||||
* @count: number of bytes to read
|
||||
* @ppos: position to read from
|
||||
*
|
||||
* Reads count bytes or the number of bytes available in the
|
||||
* current sub-buffer being read, whichever is smaller.
|
||||
*/
|
||||
static ssize_t relay_file_read(struct file *filp,
|
||||
char __user *buffer,
|
||||
size_t count,
|
||||
loff_t *ppos)
|
||||
{
|
||||
struct rchan_buf *buf = filp->private_data;
|
||||
struct inode *inode = filp->f_dentry->d_inode;
|
||||
size_t read_start, avail;
|
||||
ssize_t ret = 0;
|
||||
void *from;
|
||||
|
||||
mutex_lock(&inode->i_mutex);
|
||||
if(!relay_file_read_avail(buf, *ppos))
|
||||
goto out;
|
||||
|
||||
read_start = relay_file_read_start_pos(*ppos, buf);
|
||||
avail = relay_file_read_subbuf_avail(read_start, buf);
|
||||
if (!avail)
|
||||
goto out;
|
||||
|
||||
from = buf->start + read_start;
|
||||
ret = count = min(count, avail);
|
||||
if (copy_to_user(buffer, from, count)) {
|
||||
ret = -EFAULT;
|
||||
goto out;
|
||||
}
|
||||
relay_file_read_consume(buf, read_start, count);
|
||||
*ppos = relay_file_read_end_pos(buf, read_start, count);
|
||||
out:
|
||||
mutex_unlock(&inode->i_mutex);
|
||||
return ret;
|
||||
}
|
||||
|
||||
struct file_operations relay_file_operations = {
|
||||
.open = relay_file_open,
|
||||
.poll = relay_file_poll,
|
||||
.mmap = relay_file_mmap,
|
||||
.read = relay_file_read,
|
||||
.llseek = no_llseek,
|
||||
.release = relay_file_release,
|
||||
};
|
||||
EXPORT_SYMBOL_GPL(relay_file_operations);
|
Loading…
Reference in a new issue