[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 <linux/aio.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;
}

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)
{
	int ret = 0;

	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;
	}
	ret = __swap_writepage(page, wbc, end_swap_bio_write);
out:
	return ret;
}

int __swap_writepage(struct page *page, struct writeback_control *wbc,
	void (*end_write_func)(struct bio *, int))
{
	struct bio *bio;
	int ret = 0, rw = WRITE;
	struct swap_info_struct *sis = page_swap_info(page);

	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;

		set_page_writeback(page);
		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;
		} else {
			/*
			 * In the case of swap-over-nfs, this can be a
			 * temporary failure if the system has limited
			 * memory for allocating transmit buffers.
			 * Mark the page dirty and avoid
			 * rotate_reclaimable_page but rate-limit the
			 * messages but do not flag PageError like
			 * the normal direct-to-bio case as it could
			 * be temporary.
			 */
			set_page_dirty(page);
			ClearPageReclaim(page);
			pr_err_ratelimited("Write error on dio swapfile (%Lu)\n",
				page_file_offset(page));
		}
		end_page_writeback(page);
		return ret;
	}

	bio = get_swap_bio(GFP_NOIO, page, end_write_func);
	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>
a27bb332	23	#include <linux/aio.h>
1da177e4 LT	24	#include <asm/pgtable.h>
1da177e4 LT	25
f29ad6a9	26	static struct bio *get_swap_bio(gfp_t gfp_flags,
1da177e4 LT	27	struct page *page, bio_end_io_t end_io)
	28	{
	29	struct bio *bio;
	30
	31	bio = bio_alloc(gfp_flags, 1);
	32	if (bio) {
d4906e1a	33	bio->bi_sector = map_swap_page(page, &bio->bi_bdev);
f29ad6a9	34	bio->bi_sector <<= PAGE_SHIFT - 9;
1da177e4 LT	35	bio->bi_io_vec[0].bv_page = page;
	36	bio->bi_io_vec[0].bv_len = PAGE_SIZE;
	37	bio->bi_io_vec[0].bv_offset = 0;
	38	bio->bi_vcnt = 1;
1da177e4 LT	39	bio->bi_size = PAGE_SIZE;
	40	bio->bi_end_io = end_io;
	41	}
	42	return bio;
	43	}
	44
1eec6702	45	void end_swap_bio_write(struct bio *bio, int err)
1da177e4 LT	46	{
	47	const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
	48	struct page *page = bio->bi_io_vec[0].bv_page;
	49
6ddab3b9	50	if (!uptodate) {
1da177e4	51	SetPageError(page);
6ddab3b9 PZ	52	/*
	53	* We failed to write the page out to swap-space.
	54	* Re-dirty the page in order to avoid it being reclaimed.
	55	* Also print a dire warning that things will go BAD (tm)
	56	* very quickly.
	57	*
	58	* Also clear PG_reclaim to avoid rotate_reclaimable_page()
	59	*/
	60	set_page_dirty(page);
	61	printk(KERN_ALERT "Write-error on swap-device (%u:%u:%Lu)\n",
	62	imajor(bio->bi_bdev->bd_inode),
	63	iminor(bio->bi_bdev->bd_inode),
	64	(unsigned long long)bio->bi_sector);
	65	ClearPageReclaim(page);
	66	}
1da177e4 LT	67	end_page_writeback(page);
1da177e4 LT	68	bio_put(bio);
1da177e4 LT	69	}
1da177e4 LT	70
6712ecf8	71	void end_swap_bio_read(struct bio *bio, int err)
1da177e4 LT	72	{
	73	const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
	74	struct page *page = bio->bi_io_vec[0].bv_page;
	75
1da177e4 LT	76	if (!uptodate) {
	77	SetPageError(page);
	78	ClearPageUptodate(page);
6ddab3b9 PZ	79	printk(KERN_ALERT "Read-error on swap-device (%u:%u:%Lu)\n",
	80	imajor(bio->bi_bdev->bd_inode),
	81	iminor(bio->bi_bdev->bd_inode),
	82	(unsigned long long)bio->bi_sector);
1da177e4 LT	83	} else {
	84	SetPageUptodate(page);
	85	}
	86	unlock_page(page);
	87	bio_put(bio);
1da177e4 LT	88	}
1da177e4 LT	89
a509bc1a MG	90	int generic_swapfile_activate(struct swap_info_struct *sis,
	91	struct file *swap_file,
	92	sector_t *span)
	93	{
	94	struct address_space *mapping = swap_file->f_mapping;
	95	struct inode *inode = mapping->host;
	96	unsigned blocks_per_page;
	97	unsigned long page_no;
	98	unsigned blkbits;
	99	sector_t probe_block;
	100	sector_t last_block;
	101	sector_t lowest_block = -1;
	102	sector_t highest_block = 0;
	103	int nr_extents = 0;
	104	int ret;
	105
	106	blkbits = inode->i_blkbits;
	107	blocks_per_page = PAGE_SIZE >> blkbits;
	108
	109	/*
	110	* Map all the blocks into the extent list. This code doesn't try
	111	* to be very smart.
	112	*/
	113	probe_block = 0;
	114	page_no = 0;
	115	last_block = i_size_read(inode) >> blkbits;
	116	while ((probe_block + blocks_per_page) <= last_block &&
	117	page_no < sis->max) {
	118	unsigned block_in_page;
	119	sector_t first_block;
	120
	121	first_block = bmap(inode, probe_block);
	122	if (first_block == 0)
	123	goto bad_bmap;
	124
	125	/*
	126	* It must be PAGE_SIZE aligned on-disk
	127	*/
	128	if (first_block & (blocks_per_page - 1)) {
	129	probe_block++;
	130	goto reprobe;
	131	}
	132
	133	for (block_in_page = 1; block_in_page < blocks_per_page;
	134	block_in_page++) {
	135	sector_t block;
	136
	137	block = bmap(inode, probe_block + block_in_page);
	138	if (block == 0)
	139	goto bad_bmap;
	140	if (block != first_block + block_in_page) {
	141	/* Discontiguity */
	142	probe_block++;
	143	goto reprobe;
	144	}
	145	}
	146
	147	first_block >>= (PAGE_SHIFT - blkbits);
	148	if (page_no) { /* exclude the header page */
	149	if (first_block < lowest_block)
	150	lowest_block = first_block;
	151	if (first_block > highest_block)
	152	highest_block = first_block;
	153	}
154
155	/*
156	* We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks
157	*/
158	ret = add_swap_extent(sis, page_no, 1, first_block);
159	if (ret < 0)
160	goto out;
161	nr_extents += ret;
162	page_no++;
163	probe_block += blocks_per_page;
164	reprobe:
165	continue;
166	}
167	ret = nr_extents;
168	*span = 1 + highest_block - lowest_block;
169	if (page_no == 0)
170	page_no = 1; /* force Empty message */
171	sis->max = page_no;
172	sis->pages = page_no - 1;
173	sis->highest_bit = page_no - 1;
174	out:
175	return ret;
176	bad_bmap:
177	printk(KERN_ERR "swapon: swapfile has holes\n");
178	ret = -EINVAL;
179	goto out;
180	}
181
1da177e4 LT	182	/*
	183	* We may have stale swap cache pages in memory: notice
	184	* them here and get rid of the unnecessary final write.
	185	*/
	186	int swap_writepage(struct page page, struct writeback_control wbc)
	187	{
2f772e6c	188	int ret = 0;
1da177e4	189
a2c43eed	190	if (try_to_free_swap(page)) {
1da177e4 LT	191	unlock_page(page);
	192	goto out;
	193	}
165c8aed	194	if (frontswap_store(page) == 0) {
38b5faf4 DM	195	set_page_writeback(page);
	196	unlock_page(page);
	197	end_page_writeback(page);
	198	goto out;
	199	}
1eec6702	200	ret = __swap_writepage(page, wbc, end_swap_bio_write);
2f772e6c SJ	201	out:
	202	return ret;
	203	}
	204
1eec6702 SJ	205	int __swap_writepage(struct page page, struct writeback_control wbc,
1eec6702 SJ	206	void (end_write_func)(struct bio , int))
2f772e6c SJ	207	{
	208	struct bio *bio;
	209	int ret = 0, rw = WRITE;
	210	struct swap_info_struct *sis = page_swap_info(page);
62c230bc MG	211
	212	if (sis->flags & SWP_FILE) {
	213	struct kiocb kiocb;
	214	struct file *swap_file = sis->swap_file;
	215	struct address_space *mapping = swap_file->f_mapping;
	216	struct iovec iov = {
5a178119	217	.iov_base = kmap(page),
62c230bc MG	218	.iov_len = PAGE_SIZE,
	219	};
	220
	221	init_sync_kiocb(&kiocb, swap_file);
	222	kiocb.ki_pos = page_file_offset(page);
	223	kiocb.ki_left = PAGE_SIZE;
	224	kiocb.ki_nbytes = PAGE_SIZE;
	225
0cdc444a	226	set_page_writeback(page);
62c230bc MG	227	unlock_page(page);
	228	ret = mapping->a_ops->direct_IO(KERNEL_WRITE,
	229	&kiocb, &iov,
	230	kiocb.ki_pos, 1);
5a178119	231	kunmap(page);
62c230bc MG	232	if (ret == PAGE_SIZE) {
	233	count_vm_event(PSWPOUT);
	234	ret = 0;
2d30d31e	235	} else {
0cdc444a MG	236	/*
	237	* In the case of swap-over-nfs, this can be a
	238	* temporary failure if the system has limited
	239	* memory for allocating transmit buffers.
	240	* Mark the page dirty and avoid
	241	* rotate_reclaimable_page but rate-limit the
	242	* messages but do not flag PageError like
	243	* the normal direct-to-bio case as it could
	244	* be temporary.
	245	*/
2d30d31e	246	set_page_dirty(page);
0cdc444a MG	247	ClearPageReclaim(page);
	248	pr_err_ratelimited("Write error on dio swapfile (%Lu)\n",
	249	page_file_offset(page));
62c230bc	250	}
0cdc444a	251	end_page_writeback(page);
62c230bc MG	252	return ret;
	253	}
	254
1eec6702	255	bio = get_swap_bio(GFP_NOIO, page, end_write_func);
1da177e4 LT	256	if (bio == NULL) {
	257	set_page_dirty(page);
	258	unlock_page(page);
	259	ret = -ENOMEM;
	260	goto out;
	261	}
	262	if (wbc->sync_mode == WB_SYNC_ALL)
721a9602	263	rw \|= REQ_SYNC;
f8891e5e	264	count_vm_event(PSWPOUT);
1da177e4 LT	265	set_page_writeback(page);
	266	unlock_page(page);
	267	submit_bio(rw, bio);
	268	out:
	269	return ret;
	270	}
	271
aca8bf32	272	int swap_readpage(struct page *page)
1da177e4 LT	273	{
	274	struct bio *bio;
	275	int ret = 0;
62c230bc	276	struct swap_info_struct *sis = page_swap_info(page);
1da177e4	277
51726b12 HD	278	VM_BUG_ON(!PageLocked(page));
51726b12 HD	279	VM_BUG_ON(PageUptodate(page));
165c8aed	280	if (frontswap_load(page) == 0) {
38b5faf4 DM	281	SetPageUptodate(page);
	282	unlock_page(page);
	283	goto out;
	284	}
62c230bc MG	285
	286	if (sis->flags & SWP_FILE) {
	287	struct file *swap_file = sis->swap_file;
	288	struct address_space *mapping = swap_file->f_mapping;
	289
	290	ret = mapping->a_ops->readpage(swap_file, page);
	291	if (!ret)
	292	count_vm_event(PSWPIN);
	293	return ret;
	294	}
	295
f29ad6a9	296	bio = get_swap_bio(GFP_KERNEL, page, end_swap_bio_read);
1da177e4 LT	297	if (bio == NULL) {
	298	unlock_page(page);
	299	ret = -ENOMEM;
	300	goto out;
	301	}
f8891e5e	302	count_vm_event(PSWPIN);
1da177e4 LT	303	submit_bio(READ, bio);
	304	out:
	305	return ret;
	306	}
62c230bc MG	307
	308	int swap_set_page_dirty(struct page *page)
	309	{
	310	struct swap_info_struct *sis = page_swap_info(page);
	311
	312	if (sis->flags & SWP_FILE) {
	313	struct address_space *mapping = sis->swap_file->f_mapping;
	314	return mapping->a_ops->set_page_dirty(page);
	315	} else {
	316	return __set_page_dirty_no_writeback(page);
	317	}
	318	}