linux-hardened/mm/page_io.c
Al Viro dd0fc66fb3 [PATCH] gfp flags annotations - part 1
- added typedef unsigned int __nocast gfp_t;

 - replaced __nocast uses for gfp flags with gfp_t - it gives exactly
   the same warnings as far as sparse is concerned, doesn't change
   generated code (from gcc point of view we replaced unsigned int with
   typedef) and documents what's going on far better.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-08 15:00:57 -07:00

160 lines
3.6 KiB
C

/*
* linux/mm/page_io.c
*
* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
*
* Swap reorganised 29.12.95,
* Asynchronous swapping added 30.12.95. Stephen Tweedie
* Removed race in async swapping. 14.4.1996. Bruno Haible
* Add swap of shared pages through the page cache. 20.2.1998. Stephen Tweedie
* Always use brw_page, life becomes simpler. 12 May 1998 Eric Biederman
*/
#include <linux/mm.h>
#include <linux/kernel_stat.h>
#include <linux/pagemap.h>
#include <linux/swap.h>
#include <linux/bio.h>
#include <linux/swapops.h>
#include <linux/writeback.h>
#include <asm/pgtable.h>
static struct bio *get_swap_bio(gfp_t gfp_flags, pgoff_t index,
struct page *page, bio_end_io_t end_io)
{
struct bio *bio;
bio = bio_alloc(gfp_flags, 1);
if (bio) {
struct swap_info_struct *sis;
swp_entry_t entry = { .val = index, };
sis = get_swap_info_struct(swp_type(entry));
bio->bi_sector = map_swap_page(sis, swp_offset(entry)) *
(PAGE_SIZE >> 9);
bio->bi_bdev = sis->bdev;
bio->bi_io_vec[0].bv_page = page;
bio->bi_io_vec[0].bv_len = PAGE_SIZE;
bio->bi_io_vec[0].bv_offset = 0;
bio->bi_vcnt = 1;
bio->bi_idx = 0;
bio->bi_size = PAGE_SIZE;
bio->bi_end_io = end_io;
}
return bio;
}
static int end_swap_bio_write(struct bio *bio, unsigned int bytes_done, int err)
{
const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
struct page *page = bio->bi_io_vec[0].bv_page;
if (bio->bi_size)
return 1;
if (!uptodate)
SetPageError(page);
end_page_writeback(page);
bio_put(bio);
return 0;
}
static int end_swap_bio_read(struct bio *bio, unsigned int bytes_done, int err)
{
const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
struct page *page = bio->bi_io_vec[0].bv_page;
if (bio->bi_size)
return 1;
if (!uptodate) {
SetPageError(page);
ClearPageUptodate(page);
} else {
SetPageUptodate(page);
}
unlock_page(page);
bio_put(bio);
return 0;
}
/*
* We may have stale swap cache pages in memory: notice
* them here and get rid of the unnecessary final write.
*/
int swap_writepage(struct page *page, struct writeback_control *wbc)
{
struct bio *bio;
int ret = 0, rw = WRITE;
if (remove_exclusive_swap_page(page)) {
unlock_page(page);
goto out;
}
bio = get_swap_bio(GFP_NOIO, page->private, page, end_swap_bio_write);
if (bio == NULL) {
set_page_dirty(page);
unlock_page(page);
ret = -ENOMEM;
goto out;
}
if (wbc->sync_mode == WB_SYNC_ALL)
rw |= (1 << BIO_RW_SYNC);
inc_page_state(pswpout);
set_page_writeback(page);
unlock_page(page);
submit_bio(rw, bio);
out:
return ret;
}
int swap_readpage(struct file *file, struct page *page)
{
struct bio *bio;
int ret = 0;
BUG_ON(!PageLocked(page));
ClearPageUptodate(page);
bio = get_swap_bio(GFP_KERNEL, page->private, page, end_swap_bio_read);
if (bio == NULL) {
unlock_page(page);
ret = -ENOMEM;
goto out;
}
inc_page_state(pswpin);
submit_bio(READ, bio);
out:
return ret;
}
#ifdef CONFIG_SOFTWARE_SUSPEND
/*
* A scruffy utility function to read or write an arbitrary swap page
* and wait on the I/O. The caller must have a ref on the page.
*
* We use end_swap_bio_read() even for writes, because it happens to do what
* we want.
*/
int rw_swap_page_sync(int rw, swp_entry_t entry, struct page *page)
{
struct bio *bio;
int ret = 0;
lock_page(page);
bio = get_swap_bio(GFP_KERNEL, entry.val, page, end_swap_bio_read);
if (bio == NULL) {
unlock_page(page);
ret = -ENOMEM;
goto out;
}
submit_bio(rw | (1 << BIO_RW_SYNC), bio);
wait_on_page_locked(page);
if (!PageUptodate(page) || PageError(page))
ret = -EIO;
out:
return ret;
}
#endif