2874c5fd28
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
85 lines
2.3 KiB
C
85 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* NOMMU mmap support for RomFS on MTD devices
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*
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* Copyright © 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*/
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#include <linux/mm.h>
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#include <linux/mtd/super.h>
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#include "internal.h"
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/*
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* try to determine where a shared mapping can be made
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* - only supported for NOMMU at the moment (MMU can't doesn't copy private
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* mappings)
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* - attempts to map through to the underlying MTD device
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*/
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static unsigned long romfs_get_unmapped_area(struct file *file,
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unsigned long addr,
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unsigned long len,
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unsigned long pgoff,
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unsigned long flags)
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{
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struct inode *inode = file->f_mapping->host;
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struct mtd_info *mtd = inode->i_sb->s_mtd;
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unsigned long isize, offset, maxpages, lpages;
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int ret;
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if (!mtd)
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return (unsigned long) -ENOSYS;
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/* the mapping mustn't extend beyond the EOF */
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lpages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
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isize = i_size_read(inode);
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offset = pgoff << PAGE_SHIFT;
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maxpages = (isize + PAGE_SIZE - 1) >> PAGE_SHIFT;
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if ((pgoff >= maxpages) || (maxpages - pgoff < lpages))
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return (unsigned long) -EINVAL;
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if (addr != 0)
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return (unsigned long) -EINVAL;
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if (len > mtd->size || pgoff >= (mtd->size >> PAGE_SHIFT))
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return (unsigned long) -EINVAL;
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offset += ROMFS_I(inode)->i_dataoffset;
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if (offset >= mtd->size)
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return (unsigned long) -EINVAL;
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/* the mapping mustn't extend beyond the EOF */
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if ((offset + len) > mtd->size)
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len = mtd->size - offset;
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ret = mtd_get_unmapped_area(mtd, len, offset, flags);
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if (ret == -EOPNOTSUPP)
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ret = -ENOSYS;
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return (unsigned long) ret;
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}
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/*
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* permit a R/O mapping to be made directly through onto an MTD device if
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* possible
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*/
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static int romfs_mmap(struct file *file, struct vm_area_struct *vma)
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{
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return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -ENOSYS;
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}
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static unsigned romfs_mmap_capabilities(struct file *file)
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{
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struct mtd_info *mtd = file_inode(file)->i_sb->s_mtd;
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if (!mtd)
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return NOMMU_MAP_COPY;
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return mtd_mmap_capabilities(mtd);
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}
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const struct file_operations romfs_ro_fops = {
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.llseek = generic_file_llseek,
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.read_iter = generic_file_read_iter,
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.splice_read = generic_file_splice_read,
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.mmap = romfs_mmap,
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.get_unmapped_area = romfs_get_unmapped_area,
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.mmap_capabilities = romfs_mmap_capabilities,
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};
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