[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/gfp.h>
#include <linux/pagemap.h>
#include <linux/swap.h>
#include <linux/bio.h>
#include <linux/swapops.h>
#include <linux/buffer_head.h>
#include <linux/writeback.h>
#include <linux/frontswap.h>
#include <asm/pgtable.h>

static struct bio *get_swap_bio(gfp_t gfp_flags,
				struct page *page, bio_end_io_t end_io)
{
	struct bio *bio;

	bio = bio_alloc(gfp_flags, 1);
	if (bio) {
		bio->bi_sector = map_swap_page(page, &bio->bi_bdev);
		bio->bi_sector <<= PAGE_SHIFT - 9;
		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_size = PAGE_SIZE;
		bio->bi_end_io = end_io;
	}
	return bio;
}

static void end_swap_bio_write(struct bio *bio, int err)
{
	const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
	struct page *page = bio->bi_io_vec[0].bv_page;

	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);
}

void end_swap_bio_read(struct bio *bio, int err)
{
	const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
	struct page *page = bio->bi_io_vec[0].bv_page;

	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);
}

int generic_swapfile_activate(struct swap_info_struct *sis,
				struct file *swap_file,
				sector_t *span)
{
	struct address_space *mapping = swap_file->f_mapping;
	struct inode *inode = mapping->host;
	unsigned blocks_per_page;
	unsigned long page_no;
	unsigned blkbits;
	sector_t probe_block;
	sector_t last_block;
	sector_t lowest_block = -1;
	sector_t highest_block = 0;
	int nr_extents = 0;
	int ret;

	blkbits = inode->i_blkbits;
	blocks_per_page = PAGE_SIZE >> blkbits;

	/*
	 * Map all the blocks into the extent list.  This code doesn't try
	 * to be very smart.
	 */
	probe_block = 0;
	page_no = 0;
	last_block = i_size_read(inode) >> blkbits;
	while ((probe_block + blocks_per_page) <= last_block &&
			page_no < sis->max) {
		unsigned block_in_page;
		sector_t first_block;

		first_block = bmap(inode, probe_block);
		if (first_block == 0)
			goto bad_bmap;

		/*
		 * It must be PAGE_SIZE aligned on-disk
		 */
		if (first_block & (blocks_per_page - 1)) {
			probe_block++;
			goto reprobe;
		}

		for (block_in_page = 1; block_in_page < blocks_per_page;
					block_in_page++) {
			sector_t block;

			block = bmap(inode, probe_block + block_in_page);
			if (block == 0)
				goto bad_bmap;
			if (block != first_block + block_in_page) {
				/* Discontiguity */
				probe_block++;
				goto reprobe;
			}
		}

		first_block >>= (PAGE_SHIFT - blkbits);
		if (page_no) {	/* exclude the header page */
			if (first_block < lowest_block)
				lowest_block = first_block;
			if (first_block > highest_block)
				highest_block = first_block;
		}

		/*
		 * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks
		 */
		ret = add_swap_extent(sis, page_no, 1, first_block);
		if (ret < 0)
			goto out;
		nr_extents += ret;
		page_no++;
		probe_block += blocks_per_page;
reprobe:
		continue;
	}
	ret = nr_extents;
	*span = 1 + highest_block - lowest_block;
	if (page_no == 0)
		page_no = 1;	/* force Empty message */
	sis->max = page_no;
	sis->pages = page_no - 1;
	sis->highest_bit = page_no - 1;
out:
	return ret;
bad_bmap:
	printk(KERN_ERR "swapon: swapfile has holes\n");
	ret = -EINVAL;
	goto out;
}

/*
 * 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;
	struct swap_info_struct *sis = page_swap_info(page);

	if (try_to_free_swap(page)) {
		unlock_page(page);
		goto out;
	}
	if (frontswap_store(page) == 0) {
		set_page_writeback(page);
		unlock_page(page);
		end_page_writeback(page);
		goto out;
	}

	if (sis->flags & SWP_FILE) {
		struct kiocb kiocb;
		struct file *swap_file = sis->swap_file;
		struct address_space *mapping = swap_file->f_mapping;
		struct iovec iov = {
			.iov_base = kmap(page),
			.iov_len  = PAGE_SIZE,
		};

		init_sync_kiocb(&kiocb, swap_file);
		kiocb.ki_pos = page_file_offset(page);
		kiocb.ki_left = PAGE_SIZE;
		kiocb.ki_nbytes = PAGE_SIZE;

		unlock_page(page);
		ret = mapping->a_ops->direct_IO(KERNEL_WRITE,
						&kiocb, &iov,
						kiocb.ki_pos, 1);
		kunmap(page);
		if (ret == PAGE_SIZE) {
			count_vm_event(PSWPOUT);
			ret = 0;
		}
		return ret;
	}

	bio = get_swap_bio(GFP_NOIO, 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 |= REQ_SYNC;
	count_vm_event(PSWPOUT);
	set_page_writeback(page);
	unlock_page(page);
	submit_bio(rw, bio);
out:
	return ret;
}

int swap_readpage(struct page *page)
{
	struct bio *bio;
	int ret = 0;
	struct swap_info_struct *sis = page_swap_info(page);

	VM_BUG_ON(!PageLocked(page));
	VM_BUG_ON(PageUptodate(page));
	if (frontswap_load(page) == 0) {
		SetPageUptodate(page);
		unlock_page(page);
		goto out;
	}

	if (sis->flags & SWP_FILE) {
		struct file *swap_file = sis->swap_file;
		struct address_space *mapping = swap_file->f_mapping;

		ret = mapping->a_ops->readpage(swap_file, page);
		if (!ret)
			count_vm_event(PSWPIN);
		return ret;
	}

	bio = get_swap_bio(GFP_KERNEL, 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;
}

int swap_set_page_dirty(struct page *page)
{
	struct swap_info_struct *sis = page_swap_info(page);

	if (sis->flags & SWP_FILE) {
		struct address_space *mapping = sis->swap_file->f_mapping;
		return mapping->a_ops->set_page_dirty(page);
	} else {
		return __set_page_dirty_no_writeback(page);
	}
}
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>
5a0e3ad6	15	#include <linux/gfp.h>
1da177e4 LT	16	#include <linux/pagemap.h>
	17	#include <linux/swap.h>
	18	#include <linux/bio.h>
	19	#include <linux/swapops.h>
62c230bc	20	#include <linux/buffer_head.h>
1da177e4	21	#include <linux/writeback.h>
38b5faf4	22	#include <linux/frontswap.h>
1da177e4 LT	23	#include <asm/pgtable.h>
1da177e4 LT	24
f29ad6a9	25	static struct bio *get_swap_bio(gfp_t gfp_flags,
1da177e4 LT	26	struct page *page, bio_end_io_t end_io)
	27	{
	28	struct bio *bio;
	29
	30	bio = bio_alloc(gfp_flags, 1);
	31	if (bio) {
d4906e1a	32	bio->bi_sector = map_swap_page(page, &bio->bi_bdev);
f29ad6a9	33	bio->bi_sector <<= PAGE_SHIFT - 9;
1da177e4 LT	34	bio->bi_io_vec[0].bv_page = page;
	35	bio->bi_io_vec[0].bv_len = PAGE_SIZE;
	36	bio->bi_io_vec[0].bv_offset = 0;
	37	bio->bi_vcnt = 1;
1da177e4 LT	38	bio->bi_size = PAGE_SIZE;
	39	bio->bi_end_io = end_io;
	40	}
	41	return bio;
	42	}
	43
6712ecf8	44	static void end_swap_bio_write(struct bio *bio, int err)
1da177e4 LT	45	{
	46	const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
	47	struct page *page = bio->bi_io_vec[0].bv_page;
	48
6ddab3b9	49	if (!uptodate) {
1da177e4	50	SetPageError(page);
6ddab3b9 PZ	51	/*
	52	* We failed to write the page out to swap-space.
	53	* Re-dirty the page in order to avoid it being reclaimed.
	54	* Also print a dire warning that things will go BAD (tm)
	55	* very quickly.
	56	*
	57	* Also clear PG_reclaim to avoid rotate_reclaimable_page()
	58	*/
	59	set_page_dirty(page);
	60	printk(KERN_ALERT "Write-error on swap-device (%u:%u:%Lu)\n",
	61	imajor(bio->bi_bdev->bd_inode),
	62	iminor(bio->bi_bdev->bd_inode),
	63	(unsigned long long)bio->bi_sector);
	64	ClearPageReclaim(page);
	65	}
1da177e4 LT	66	end_page_writeback(page);
1da177e4 LT	67	bio_put(bio);
1da177e4 LT	68	}
1da177e4 LT	69
6712ecf8	70	void end_swap_bio_read(struct bio *bio, int err)
1da177e4 LT	71	{
	72	const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
	73	struct page *page = bio->bi_io_vec[0].bv_page;
	74
1da177e4 LT	75	if (!uptodate) {
	76	SetPageError(page);
	77	ClearPageUptodate(page);
6ddab3b9 PZ	78	printk(KERN_ALERT "Read-error on swap-device (%u:%u:%Lu)\n",
	79	imajor(bio->bi_bdev->bd_inode),
	80	iminor(bio->bi_bdev->bd_inode),
	81	(unsigned long long)bio->bi_sector);
1da177e4 LT	82	} else {
	83	SetPageUptodate(page);
	84	}
	85	unlock_page(page);
	86	bio_put(bio);
1da177e4 LT	87	}
1da177e4 LT	88
a509bc1a MG	89	int generic_swapfile_activate(struct swap_info_struct *sis,
	90	struct file *swap_file,
	91	sector_t *span)
	92	{
	93	struct address_space *mapping = swap_file->f_mapping;
	94	struct inode *inode = mapping->host;
	95	unsigned blocks_per_page;
	96	unsigned long page_no;
	97	unsigned blkbits;
	98	sector_t probe_block;
	99	sector_t last_block;
	100	sector_t lowest_block = -1;
	101	sector_t highest_block = 0;
	102	int nr_extents = 0;
	103	int ret;
	104
	105	blkbits = inode->i_blkbits;
	106	blocks_per_page = PAGE_SIZE >> blkbits;
	107
	108	/*
	109	* Map all the blocks into the extent list. This code doesn't try
	110	* to be very smart.
	111	*/
	112	probe_block = 0;
	113	page_no = 0;
	114	last_block = i_size_read(inode) >> blkbits;
	115	while ((probe_block + blocks_per_page) <= last_block &&
	116	page_no < sis->max) {
	117	unsigned block_in_page;
	118	sector_t first_block;
	119
	120	first_block = bmap(inode, probe_block);
	121	if (first_block == 0)
	122	goto bad_bmap;
	123
	124	/*
	125	* It must be PAGE_SIZE aligned on-disk
	126	*/
	127	if (first_block & (blocks_per_page - 1)) {
	128	probe_block++;
	129	goto reprobe;
	130	}
	131
	132	for (block_in_page = 1; block_in_page < blocks_per_page;
	133	block_in_page++) {
	134	sector_t block;
	135
	136	block = bmap(inode, probe_block + block_in_page);
	137	if (block == 0)
	138	goto bad_bmap;
	139	if (block != first_block + block_in_page) {
	140	/* Discontiguity */
	141	probe_block++;
	142	goto reprobe;
	143	}
	144	}
	145
	146	first_block >>= (PAGE_SHIFT - blkbits);
	147	if (page_no) { /* exclude the header page */
	148	if (first_block < lowest_block)
	149	lowest_block = first_block;
	150	if (first_block > highest_block)
	151	highest_block = first_block;
	152	}
153
154	/*
155	* We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks
156	*/
157	ret = add_swap_extent(sis, page_no, 1, first_block);
158	if (ret < 0)
159	goto out;
160	nr_extents += ret;
161	page_no++;
162	probe_block += blocks_per_page;
163	reprobe:
164	continue;
165	}
166	ret = nr_extents;
167	*span = 1 + highest_block - lowest_block;
168	if (page_no == 0)
169	page_no = 1; /* force Empty message */
170	sis->max = page_no;
171	sis->pages = page_no - 1;
172	sis->highest_bit = page_no - 1;
173	out:
174	return ret;
175	bad_bmap:
176	printk(KERN_ERR "swapon: swapfile has holes\n");
177	ret = -EINVAL;
178	goto out;
179	}
180
1da177e4 LT	181	/*
	182	* We may have stale swap cache pages in memory: notice
	183	* them here and get rid of the unnecessary final write.
	184	*/
	185	int swap_writepage(struct page page, struct writeback_control wbc)
	186	{
	187	struct bio *bio;
	188	int ret = 0, rw = WRITE;
62c230bc	189	struct swap_info_struct *sis = page_swap_info(page);
1da177e4	190
a2c43eed	191	if (try_to_free_swap(page)) {
1da177e4 LT	192	unlock_page(page);
	193	goto out;
	194	}
165c8aed	195	if (frontswap_store(page) == 0) {
38b5faf4 DM	196	set_page_writeback(page);
	197	unlock_page(page);
	198	end_page_writeback(page);
	199	goto out;
	200	}
62c230bc MG	201
	202	if (sis->flags & SWP_FILE) {
	203	struct kiocb kiocb;
	204	struct file *swap_file = sis->swap_file;
	205	struct address_space *mapping = swap_file->f_mapping;
	206	struct iovec iov = {
5a178119	207	.iov_base = kmap(page),
62c230bc MG	208	.iov_len = PAGE_SIZE,
	209	};
	210
	211	init_sync_kiocb(&kiocb, swap_file);
	212	kiocb.ki_pos = page_file_offset(page);
	213	kiocb.ki_left = PAGE_SIZE;
	214	kiocb.ki_nbytes = PAGE_SIZE;
	215
	216	unlock_page(page);
	217	ret = mapping->a_ops->direct_IO(KERNEL_WRITE,
	218	&kiocb, &iov,
	219	kiocb.ki_pos, 1);
5a178119	220	kunmap(page);
62c230bc MG	221	if (ret == PAGE_SIZE) {
	222	count_vm_event(PSWPOUT);
	223	ret = 0;
	224	}
	225	return ret;
	226	}
	227
f29ad6a9	228	bio = get_swap_bio(GFP_NOIO, page, end_swap_bio_write);
1da177e4 LT	229	if (bio == NULL) {
	230	set_page_dirty(page);
	231	unlock_page(page);
	232	ret = -ENOMEM;
	233	goto out;
	234	}
	235	if (wbc->sync_mode == WB_SYNC_ALL)
721a9602	236	rw \|= REQ_SYNC;
f8891e5e	237	count_vm_event(PSWPOUT);
1da177e4 LT	238	set_page_writeback(page);
	239	unlock_page(page);
	240	submit_bio(rw, bio);
	241	out:
	242	return ret;
	243	}
	244
aca8bf32	245	int swap_readpage(struct page *page)
1da177e4 LT	246	{
	247	struct bio *bio;
	248	int ret = 0;
62c230bc	249	struct swap_info_struct *sis = page_swap_info(page);
1da177e4	250
51726b12 HD	251	VM_BUG_ON(!PageLocked(page));
51726b12 HD	252	VM_BUG_ON(PageUptodate(page));
165c8aed	253	if (frontswap_load(page) == 0) {
38b5faf4 DM	254	SetPageUptodate(page);
	255	unlock_page(page);
	256	goto out;
	257	}
62c230bc MG	258
	259	if (sis->flags & SWP_FILE) {
	260	struct file *swap_file = sis->swap_file;
	261	struct address_space *mapping = swap_file->f_mapping;
	262
	263	ret = mapping->a_ops->readpage(swap_file, page);
	264	if (!ret)
	265	count_vm_event(PSWPIN);
	266	return ret;
	267	}
	268
f29ad6a9	269	bio = get_swap_bio(GFP_KERNEL, page, end_swap_bio_read);
1da177e4 LT	270	if (bio == NULL) {
	271	unlock_page(page);
	272	ret = -ENOMEM;
	273	goto out;
	274	}
f8891e5e	275	count_vm_event(PSWPIN);
1da177e4 LT	276	submit_bio(READ, bio);
	277	out:
	278	return ret;
	279	}
62c230bc MG	280
	281	int swap_set_page_dirty(struct page *page)
	282	{
	283	struct swap_info_struct *sis = page_swap_info(page);
	284
	285	if (sis->flags & SWP_FILE) {
	286	struct address_space *mapping = sis->swap_file->f_mapping;
	287	return mapping->a_ops->set_page_dirty(page);
	288	} else {
	289	return __set_page_dirty_no_writeback(page);
	290	}
	291	}