[GitHub/mt8127/android_kernel_alcatel_ttab.git] / mm / page_io.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);
		/*
		 * We failed to write the page out to swap-space.
		 * Re-dirty the page in order to avoid it being reclaimed.
		 * Also print a dire warning that things will go BAD (tm)
		 * very quickly.
		 *
		 * Also clear PG_reclaim to avoid rotate_reclaimable_page()
		 */
		set_page_dirty(page);
		printk(KERN_ALERT "Write-error on swap-device (%u:%u:%Lu)\n",
				imajor(bio->bi_bdev->bd_inode),
				iminor(bio->bi_bdev->bd_inode),
				(unsigned long long)bio->bi_sector);
		ClearPageReclaim(page);
	}
	end_page_writeback(page);
	bio_put(bio);
	return 0;
}

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);
		printk(KERN_ALERT "Read-error on swap-device (%u:%u:%Lu)\n",
				imajor(bio->bi_bdev->bd_inode),
				iminor(bio->bi_bdev->bd_inode),
				(unsigned long long)bio->bi_sector);
	} 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), 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);
	count_vm_event(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), page,
				end_swap_bio_read);
	if (bio == NULL) {
		unlock_page(page);
		ret = -ENOMEM;
		goto out;
	}
	count_vm_event(PSWPIN);
	submit_bio(READ, bio);
out:
	return ret;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/mm/page_io.c
	3	*
	4	* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
	5	*
	6	* Swap reorganised 29.12.95,
	7	* Asynchronous swapping added 30.12.95. Stephen Tweedie
	8	* Removed race in async swapping. 14.4.1996. Bruno Haible
	9	* Add swap of shared pages through the page cache. 20.2.1998. Stephen Tweedie
	10	* Always use brw_page, life becomes simpler. 12 May 1998 Eric Biederman
	11	*/
	12
	13	#include <linux/mm.h>
	14	#include <linux/kernel_stat.h>
	15	#include <linux/pagemap.h>
	16	#include <linux/swap.h>
	17	#include <linux/bio.h>
	18	#include <linux/swapops.h>
	19	#include <linux/writeback.h>
	20	#include <asm/pgtable.h>
	21
dd0fc66f	22	static struct bio *get_swap_bio(gfp_t gfp_flags, pgoff_t index,
1da177e4 LT	23	struct page *page, bio_end_io_t end_io)
	24	{
	25	struct bio *bio;
	26
	27	bio = bio_alloc(gfp_flags, 1);
	28	if (bio) {
	29	struct swap_info_struct *sis;
	30	swp_entry_t entry = { .val = index, };
	31
	32	sis = get_swap_info_struct(swp_type(entry));
	33	bio->bi_sector = map_swap_page(sis, swp_offset(entry)) *
	34	(PAGE_SIZE >> 9);
	35	bio->bi_bdev = sis->bdev;
	36	bio->bi_io_vec[0].bv_page = page;
	37	bio->bi_io_vec[0].bv_len = PAGE_SIZE;
	38	bio->bi_io_vec[0].bv_offset = 0;
	39	bio->bi_vcnt = 1;
	40	bio->bi_idx = 0;
	41	bio->bi_size = PAGE_SIZE;
	42	bio->bi_end_io = end_io;
	43	}
	44	return bio;
	45	}
	46
	47	static int end_swap_bio_write(struct bio *bio, unsigned int bytes_done, int err)
	48	{
	49	const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
	50	struct page *page = bio->bi_io_vec[0].bv_page;
	51
	52	if (bio->bi_size)
	53	return 1;
	54
6ddab3b9	55	if (!uptodate) {
1da177e4	56	SetPageError(page);
6ddab3b9 PZ	57	/*
	58	* We failed to write the page out to swap-space.
	59	* Re-dirty the page in order to avoid it being reclaimed.
	60	* Also print a dire warning that things will go BAD (tm)
	61	* very quickly.
	62	*
	63	* Also clear PG_reclaim to avoid rotate_reclaimable_page()
	64	*/
	65	set_page_dirty(page);
	66	printk(KERN_ALERT "Write-error on swap-device (%u:%u:%Lu)\n",
	67	imajor(bio->bi_bdev->bd_inode),
	68	iminor(bio->bi_bdev->bd_inode),
	69	(unsigned long long)bio->bi_sector);
	70	ClearPageReclaim(page);
	71	}
1da177e4 LT	72	end_page_writeback(page);
	73	bio_put(bio);
	74	return 0;
	75	}
	76
546e0d27	77	int end_swap_bio_read(struct bio *bio, unsigned int bytes_done, int err)
1da177e4 LT	78	{
	79	const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
	80	struct page *page = bio->bi_io_vec[0].bv_page;
	81
	82	if (bio->bi_size)
	83	return 1;
	84
	85	if (!uptodate) {
	86	SetPageError(page);
	87	ClearPageUptodate(page);
6ddab3b9 PZ	88	printk(KERN_ALERT "Read-error on swap-device (%u:%u:%Lu)\n",
	89	imajor(bio->bi_bdev->bd_inode),
	90	iminor(bio->bi_bdev->bd_inode),
	91	(unsigned long long)bio->bi_sector);
1da177e4 LT	92	} else {
	93	SetPageUptodate(page);
	94	}
	95	unlock_page(page);
	96	bio_put(bio);
	97	return 0;
	98	}
	99
	100	/*
	101	* We may have stale swap cache pages in memory: notice
	102	* them here and get rid of the unnecessary final write.
	103	*/
	104	int swap_writepage(struct page page, struct writeback_control wbc)
	105	{
	106	struct bio *bio;
	107	int ret = 0, rw = WRITE;
	108
	109	if (remove_exclusive_swap_page(page)) {
	110	unlock_page(page);
	111	goto out;
	112	}
4c21e2f2 HD	113	bio = get_swap_bio(GFP_NOIO, page_private(page), page,
4c21e2f2 HD	114	end_swap_bio_write);
1da177e4 LT	115	if (bio == NULL) {
	116	set_page_dirty(page);
	117	unlock_page(page);
	118	ret = -ENOMEM;
	119	goto out;
	120	}
	121	if (wbc->sync_mode == WB_SYNC_ALL)
	122	rw \|= (1 << BIO_RW_SYNC);
f8891e5e	123	count_vm_event(PSWPOUT);
1da177e4 LT	124	set_page_writeback(page);
	125	unlock_page(page);
	126	submit_bio(rw, bio);
	127	out:
	128	return ret;
	129	}
	130
	131	int swap_readpage(struct file file, struct page page)
	132	{
	133	struct bio *bio;
	134	int ret = 0;
	135
	136	BUG_ON(!PageLocked(page));
	137	ClearPageUptodate(page);
4c21e2f2 HD	138	bio = get_swap_bio(GFP_KERNEL, page_private(page), page,
4c21e2f2 HD	139	end_swap_bio_read);
1da177e4 LT	140	if (bio == NULL) {
	141	unlock_page(page);
	142	ret = -ENOMEM;
	143	goto out;
	144	}
f8891e5e	145	count_vm_event(PSWPIN);
1da177e4 LT	146	submit_bio(READ, bio);
	147	out:
	148	return ret;
	149	}