[thirdparty/linux.git] / mm / page_io.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  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/blkdev.h>
#include <linux/psi.h>
#include <linux/uio.h>
#include <linux/sched/task.h>
#include <linux/delayacct.h>

void end_swap_bio_write(struct bio *bio)
{
	struct page *page = bio_first_page_all(bio);

	if (bio->bi_status) {
		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 folio_rotate_reclaimable()
		 */
		set_page_dirty(page);
		pr_alert_ratelimited("Write-error on swap-device (%u:%u:%llu)\n",
				     MAJOR(bio_dev(bio)), MINOR(bio_dev(bio)),
				     (unsigned long long)bio->bi_iter.bi_sector);
		ClearPageReclaim(page);
	}
	end_page_writeback(page);
	bio_put(bio);
}

static void end_swap_bio_read(struct bio *bio)
{
	struct page *page = bio_first_page_all(bio);
	struct task_struct *waiter = bio->bi_private;

	if (bio->bi_status) {
		SetPageError(page);
		ClearPageUptodate(page);
		pr_alert_ratelimited("Read-error on swap-device (%u:%u:%llu)\n",
				     MAJOR(bio_dev(bio)), MINOR(bio_dev(bio)),
				     (unsigned long long)bio->bi_iter.bi_sector);
		goto out;
	}

	SetPageUptodate(page);
out:
	unlock_page(page);
	WRITE_ONCE(bio->bi_private, NULL);
	bio_put(bio);
	if (waiter) {
		blk_wake_io_task(waiter);
		put_task_struct(waiter);
	}
}

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 tree.  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;

		cond_resched();

		first_block = probe_block;
		ret = bmap(inode, &first_block);
		if (ret || !first_block)
			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 = probe_block + block_in_page;
			ret = bmap(inode, &block);
			if (ret || !block)
				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:
	pr_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;
	}
	/*
	 * Arch code may have to preserve more data than just the page
	 * contents, e.g. memory tags.
	 */
	ret = arch_prepare_to_swap(page);
	if (ret) {
		set_page_dirty(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;
}

static inline void count_swpout_vm_event(struct page *page)
{
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	if (unlikely(PageTransHuge(page)))
		count_vm_event(THP_SWPOUT);
#endif
	count_vm_events(PSWPOUT, thp_nr_pages(page));
}

#if defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
static void bio_associate_blkg_from_page(struct bio *bio, struct page *page)
{
	struct cgroup_subsys_state *css;
	struct mem_cgroup *memcg;

	memcg = page_memcg(page);
	if (!memcg)
		return;

	rcu_read_lock();
	css = cgroup_e_css(memcg->css.cgroup, &io_cgrp_subsys);
	bio_associate_blkg_from_css(bio, css);
	rcu_read_unlock();
}
#else
#define bio_associate_blkg_from_page(bio, page)		do { } while (0)
#endif /* CONFIG_MEMCG && CONFIG_BLK_CGROUP */

int __swap_writepage(struct page *page, struct writeback_control *wbc,
		bio_end_io_t end_write_func)
{
	struct bio *bio;
	int ret;
	struct swap_info_struct *sis = page_swap_info(page);

	VM_BUG_ON_PAGE(!PageSwapCache(page), page);
	if (data_race(sis->flags & SWP_FS_OPS)) {
		struct kiocb kiocb;
		struct file *swap_file = sis->swap_file;
		struct address_space *mapping = swap_file->f_mapping;
		struct bio_vec bv = {
			.bv_page = page,
			.bv_len  = PAGE_SIZE,
			.bv_offset = 0
		};
		struct iov_iter from;

		iov_iter_bvec(&from, WRITE, &bv, 1, PAGE_SIZE);
		init_sync_kiocb(&kiocb, swap_file);
		kiocb.ki_pos = page_file_offset(page);

		set_page_writeback(page);
		unlock_page(page);
		ret = mapping->a_ops->direct_IO(&kiocb, &from);
		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
			 * folio_rotate_reclaimable 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 (%llu)\n",
					   page_file_offset(page));
		}
		end_page_writeback(page);
		return ret;
	}

	ret = bdev_write_page(sis->bdev, swap_page_sector(page), page, wbc);
	if (!ret) {
		count_swpout_vm_event(page);
		return 0;
	}

	bio = bio_alloc(sis->bdev, 1,
			REQ_OP_WRITE | REQ_SWAP | wbc_to_write_flags(wbc),
			GFP_NOIO);
	bio->bi_iter.bi_sector = swap_page_sector(page);
	bio->bi_end_io = end_write_func;
	bio_add_page(bio, page, thp_size(page), 0);

	bio_associate_blkg_from_page(bio, page);
	count_swpout_vm_event(page);
	set_page_writeback(page);
	unlock_page(page);
	submit_bio(bio);

	return 0;
}

int swap_readpage(struct page *page, bool synchronous)
{
	struct bio *bio;
	int ret = 0;
	struct swap_info_struct *sis = page_swap_info(page);
	bool workingset = PageWorkingset(page);
	unsigned long pflags;

	VM_BUG_ON_PAGE(!PageSwapCache(page) && !synchronous, page);
	VM_BUG_ON_PAGE(!PageLocked(page), page);
	VM_BUG_ON_PAGE(PageUptodate(page), page);

	/*
	 * Count submission time as memory stall. When the device is congested,
	 * or the submitting cgroup IO-throttled, submission can be a
	 * significant part of overall IO time.
	 */
	if (workingset)
		psi_memstall_enter(&pflags);
	delayacct_swapin_start();

	if (frontswap_load(page) == 0) {
		SetPageUptodate(page);
		unlock_page(page);
		goto out;
	}

	if (data_race(sis->flags & SWP_FS_OPS)) {
		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);
		goto out;
	}

	if (sis->flags & SWP_SYNCHRONOUS_IO) {
		ret = bdev_read_page(sis->bdev, swap_page_sector(page), page);
		if (!ret) {
			count_vm_event(PSWPIN);
			goto out;
		}
	}

	ret = 0;
	bio = bio_alloc(sis->bdev, 1, REQ_OP_READ, GFP_KERNEL);
	bio->bi_iter.bi_sector = swap_page_sector(page);
	bio->bi_end_io = end_swap_bio_read;
	bio_add_page(bio, page, thp_size(page), 0);
	/*
	 * Keep this task valid during swap readpage because the oom killer may
	 * attempt to access it in the page fault retry time check.
	 */
	if (synchronous) {
		bio->bi_opf |= REQ_POLLED;
		get_task_struct(current);
		bio->bi_private = current;
	}
	count_vm_event(PSWPIN);
	bio_get(bio);
	submit_bio(bio);
	while (synchronous) {
		set_current_state(TASK_UNINTERRUPTIBLE);
		if (!READ_ONCE(bio->bi_private))
			break;

		if (!bio_poll(bio, NULL, 0))
			blk_io_schedule();
	}
	__set_current_state(TASK_RUNNING);
	bio_put(bio);

out:
	if (workingset)
		psi_memstall_leave(&pflags);
	delayacct_swapin_end();
	return ret;
}

bool swap_dirty_folio(struct address_space *mapping, struct folio *folio)
{
	struct swap_info_struct *sis = swp_swap_info(folio_swap_entry(folio));

	if (data_race(sis->flags & SWP_FS_OPS)) {
		const struct address_space_operations *aops;

		mapping = sis->swap_file->f_mapping;
		aops = mapping->a_ops;

		VM_BUG_ON_FOLIO(!folio_test_swapcache(folio), folio);
		return aops->dirty_folio(mapping, folio);
	} else {
		return noop_dirty_folio(mapping, folio);
	}
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	/*
	3	* linux/mm/page_io.c
	4	*
	5	* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
	6	*
	7	* Swap reorganised 29.12.95,
	8	* Asynchronous swapping added 30.12.95. Stephen Tweedie
	9	* Removed race in async swapping. 14.4.1996. Bruno Haible
	10	* Add swap of shared pages through the page cache. 20.2.1998. Stephen Tweedie
	11	* Always use brw_page, life becomes simpler. 12 May 1998 Eric Biederman
	12	*/
	13
	14	#include <linux/mm.h>
	15	#include <linux/kernel_stat.h>
5a0e3ad6	16	#include <linux/gfp.h>
1da177e4 LT	17	#include <linux/pagemap.h>
	18	#include <linux/swap.h>
	19	#include <linux/bio.h>
	20	#include <linux/swapops.h>
62c230bc	21	#include <linux/buffer_head.h>
1da177e4	22	#include <linux/writeback.h>
38b5faf4	23	#include <linux/frontswap.h>
b430e9d1	24	#include <linux/blkdev.h>
93779069	25	#include <linux/psi.h>
e2e40f2c	26	#include <linux/uio.h>
b0ba2d0f	27	#include <linux/sched/task.h>
a3d5dc90	28	#include <linux/delayacct.h>
1da177e4	29
4246a0b6	30	void end_swap_bio_write(struct bio *bio)
1da177e4	31	{
263663cd	32	struct page *page = bio_first_page_all(bio);
1da177e4	33
4e4cbee9	34	if (bio->bi_status) {
1da177e4	35	SetPageError(page);
6ddab3b9 PZ	36	/*
	37	* We failed to write the page out to swap-space.
	38	* Re-dirty the page in order to avoid it being reclaimed.
	39	* Also print a dire warning that things will go BAD (tm)
	40	* very quickly.
	41	*
575ced1c	42	* Also clear PG_reclaim to avoid folio_rotate_reclaimable()
6ddab3b9 PZ	43	*/
6ddab3b9 PZ	44	set_page_dirty(page);
25eaab43 GD	45	pr_alert_ratelimited("Write-error on swap-device (%u:%u:%llu)\n",
	46	MAJOR(bio_dev(bio)), MINOR(bio_dev(bio)),
	47	(unsigned long long)bio->bi_iter.bi_sector);
6ddab3b9 PZ	48	ClearPageReclaim(page);
6ddab3b9 PZ	49	}
1da177e4 LT	50	end_page_writeback(page);
1da177e4 LT	51	bio_put(bio);
1da177e4 LT	52	}
1da177e4 LT	53
4246a0b6	54	static void end_swap_bio_read(struct bio *bio)
1da177e4	55	{
263663cd	56	struct page *page = bio_first_page_all(bio);
23955622	57	struct task_struct *waiter = bio->bi_private;
1da177e4	58
4e4cbee9	59	if (bio->bi_status) {
1da177e4 LT	60	SetPageError(page);
1da177e4 LT	61	ClearPageUptodate(page);
25eaab43 GD	62	pr_alert_ratelimited("Read-error on swap-device (%u:%u:%llu)\n",
	63	MAJOR(bio_dev(bio)), MINOR(bio_dev(bio)),
	64	(unsigned long long)bio->bi_iter.bi_sector);
b430e9d1	65	goto out;
1da177e4	66	}
b430e9d1 MK	67
b430e9d1 MK	68	SetPageUptodate(page);
b430e9d1	69	out:
1da177e4	70	unlock_page(page);
23955622	71	WRITE_ONCE(bio->bi_private, NULL);
1da177e4	72	bio_put(bio);
87518530 ON	73	if (waiter) {
	74	blk_wake_io_task(waiter);
	75	put_task_struct(waiter);
	76	}
1da177e4 LT	77	}
1da177e4 LT	78
a509bc1a MG	79	int generic_swapfile_activate(struct swap_info_struct *sis,
	80	struct file *swap_file,
	81	sector_t *span)
	82	{
	83	struct address_space *mapping = swap_file->f_mapping;
	84	struct inode *inode = mapping->host;
	85	unsigned blocks_per_page;
	86	unsigned long page_no;
	87	unsigned blkbits;
	88	sector_t probe_block;
	89	sector_t last_block;
	90	sector_t lowest_block = -1;
	91	sector_t highest_block = 0;
	92	int nr_extents = 0;
	93	int ret;
	94
	95	blkbits = inode->i_blkbits;
	96	blocks_per_page = PAGE_SIZE >> blkbits;
	97
	98	/*
4efaceb1	99	* Map all the blocks into the extent tree. This code doesn't try
a509bc1a MG	100	* to be very smart.
	101	*/
	102	probe_block = 0;
	103	page_no = 0;
	104	last_block = i_size_read(inode) >> blkbits;
	105	while ((probe_block + blocks_per_page) <= last_block &&
	106	page_no < sis->max) {
	107	unsigned block_in_page;
	108	sector_t first_block;
	109
7e4411bf MP	110	cond_resched();
7e4411bf MP	111
30460e1e CM	112	first_block = probe_block;
	113	ret = bmap(inode, &first_block);
	114	if (ret \|\| !first_block)
a509bc1a MG	115	goto bad_bmap;
	116
	117	/*
	118	* It must be PAGE_SIZE aligned on-disk
	119	*/
	120	if (first_block & (blocks_per_page - 1)) {
	121	probe_block++;
	122	goto reprobe;
	123	}
	124
	125	for (block_in_page = 1; block_in_page < blocks_per_page;
	126	block_in_page++) {
	127	sector_t block;
	128
30460e1e CM	129	block = probe_block + block_in_page;
	130	ret = bmap(inode, &block);
	131	if (ret \|\| !block)
a509bc1a	132	goto bad_bmap;
30460e1e	133
a509bc1a MG	134	if (block != first_block + block_in_page) {
	135	/* Discontiguity */
	136	probe_block++;
	137	goto reprobe;
	138	}
	139	}
	140
	141	first_block >>= (PAGE_SHIFT - blkbits);
	142	if (page_no) { /* exclude the header page */
	143	if (first_block < lowest_block)
	144	lowest_block = first_block;
	145	if (first_block > highest_block)
	146	highest_block = first_block;
	147	}
	148
	149	/*
	150	* We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks
	151	*/
	152	ret = add_swap_extent(sis, page_no, 1, first_block);
	153	if (ret < 0)
	154	goto out;
	155	nr_extents += ret;
	156	page_no++;
	157	probe_block += blocks_per_page;
	158	reprobe:
	159	continue;
	160	}
	161	ret = nr_extents;
	162	*span = 1 + highest_block - lowest_block;
	163	if (page_no == 0)
	164	page_no = 1; /* force Empty message */
	165	sis->max = page_no;
	166	sis->pages = page_no - 1;
	167	sis->highest_bit = page_no - 1;
	168	out:
	169	return ret;
	170	bad_bmap:
1170532b	171	pr_err("swapon: swapfile has holes\n");
a509bc1a MG	172	ret = -EINVAL;
	173	goto out;
	174	}
	175
1da177e4 LT	176	/*
	177	* We may have stale swap cache pages in memory: notice
	178	* them here and get rid of the unnecessary final write.
	179	*/
	180	int swap_writepage(struct page page, struct writeback_control wbc)
	181	{
2f772e6c	182	int ret = 0;
1da177e4	183
a2c43eed	184	if (try_to_free_swap(page)) {
1da177e4 LT	185	unlock_page(page);
	186	goto out;
	187	}
8a84802e SP	188	/*
	189	* Arch code may have to preserve more data than just the page
	190	* contents, e.g. memory tags.
	191	*/
	192	ret = arch_prepare_to_swap(page);
	193	if (ret) {
	194	set_page_dirty(page);
	195	unlock_page(page);
	196	goto out;
	197	}
165c8aed	198	if (frontswap_store(page) == 0) {
38b5faf4 DM	199	set_page_writeback(page);
	200	unlock_page(page);
	201	end_page_writeback(page);
	202	goto out;
	203	}
1eec6702	204	ret = __swap_writepage(page, wbc, end_swap_bio_write);
2f772e6c SJ	205	out:
	206	return ret;
	207	}
	208
225311a4 HY	209	static inline void count_swpout_vm_event(struct page *page)
	210	{
	211	#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	212	if (unlikely(PageTransHuge(page)))
	213	count_vm_event(THP_SWPOUT);
	214	#endif
6c357848	215	count_vm_events(PSWPOUT, thp_nr_pages(page));
225311a4 HY	216	}
225311a4 HY	217
a18b9b15 CH	218	#if defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
	219	static void bio_associate_blkg_from_page(struct bio bio, struct page page)
	220	{
	221	struct cgroup_subsys_state *css;
bcfe06bf	222	struct mem_cgroup *memcg;
a18b9b15	223
bcfe06bf RG	224	memcg = page_memcg(page);
bcfe06bf RG	225	if (!memcg)
a18b9b15 CH	226	return;
	227
	228	rcu_read_lock();
bcfe06bf	229	css = cgroup_e_css(memcg->css.cgroup, &io_cgrp_subsys);
a18b9b15 CH	230	bio_associate_blkg_from_css(bio, css);
	231	rcu_read_unlock();
	232	}
	233	#else
	234	#define bio_associate_blkg_from_page(bio, page) do { } while (0)
	235	#endif /* CONFIG_MEMCG && CONFIG_BLK_CGROUP */
	236
1eec6702	237	int __swap_writepage(struct page page, struct writeback_control wbc,
4246a0b6	238	bio_end_io_t end_write_func)
2f772e6c SJ	239	{
2f772e6c SJ	240	struct bio *bio;
4e49ea4a	241	int ret;
2f772e6c	242	struct swap_info_struct *sis = page_swap_info(page);
62c230bc	243
cc30c5d6	244	VM_BUG_ON_PAGE(!PageSwapCache(page), page);
32646315	245	if (data_race(sis->flags & SWP_FS_OPS)) {
62c230bc MG	246	struct kiocb kiocb;
	247	struct file *swap_file = sis->swap_file;
	248	struct address_space *mapping = swap_file->f_mapping;
62a8067a AV	249	struct bio_vec bv = {
	250	.bv_page = page,
	251	.bv_len = PAGE_SIZE,
	252	.bv_offset = 0
	253	};
05afcb77	254	struct iov_iter from;
62c230bc	255
aa563d7b	256	iov_iter_bvec(&from, WRITE, &bv, 1, PAGE_SIZE);
62c230bc MG	257	init_sync_kiocb(&kiocb, swap_file);
62c230bc MG	258	kiocb.ki_pos = page_file_offset(page);
62c230bc	259
0cdc444a	260	set_page_writeback(page);
62c230bc	261	unlock_page(page);
c8b8e32d	262	ret = mapping->a_ops->direct_IO(&kiocb, &from);
62c230bc MG	263	if (ret == PAGE_SIZE) {
	264	count_vm_event(PSWPOUT);
	265	ret = 0;
2d30d31e	266	} else {
0cdc444a MG	267	/*
	268	* In the case of swap-over-nfs, this can be a
	269	* temporary failure if the system has limited
	270	* memory for allocating transmit buffers.
	271	* Mark the page dirty and avoid
575ced1c	272	* folio_rotate_reclaimable but rate-limit the
0cdc444a MG	273	* messages but do not flag PageError like
	274	* the normal direct-to-bio case as it could
	275	* be temporary.
	276	*/
2d30d31e	277	set_page_dirty(page);
0cdc444a	278	ClearPageReclaim(page);
1170532b JP	279	pr_err_ratelimited("Write error on dio swapfile (%llu)\n",
1170532b JP	280	page_file_offset(page));
62c230bc	281	}
0cdc444a	282	end_page_writeback(page);
62c230bc MG	283	return ret;
	284	}
	285
dd6bd0d9 MW	286	ret = bdev_write_page(sis->bdev, swap_page_sector(page), page, wbc);
dd6bd0d9 MW	287	if (!ret) {
225311a4	288	count_swpout_vm_event(page);
dd6bd0d9 MW	289	return 0;
	290	}
	291
07888c66 CH	292	bio = bio_alloc(sis->bdev, 1,
	293	REQ_OP_WRITE \| REQ_SWAP \| wbc_to_write_flags(wbc),
	294	GFP_NOIO);
48d15436	295	bio->bi_iter.bi_sector = swap_page_sector(page);
48d15436 CH	296	bio->bi_end_io = end_write_func;
	297	bio_add_page(bio, page, thp_size(page), 0);
	298
6a7f6d86	299	bio_associate_blkg_from_page(bio, page);
225311a4	300	count_swpout_vm_event(page);
1da177e4 LT	301	set_page_writeback(page);
1da177e4 LT	302	unlock_page(page);
4e49ea4a	303	submit_bio(bio);
548d9782 ML	304
548d9782 ML	305	return 0;
1da177e4 LT	306	}
1da177e4 LT	307
0bcac06f	308	int swap_readpage(struct page *page, bool synchronous)
1da177e4 LT	309	{
	310	struct bio *bio;
	311	int ret = 0;
62c230bc	312	struct swap_info_struct *sis = page_swap_info(page);
d8c47cc7	313	bool workingset = PageWorkingset(page);
93779069	314	unsigned long pflags;
1da177e4	315
0bcac06f	316	VM_BUG_ON_PAGE(!PageSwapCache(page) && !synchronous, page);
309381fe SL	317	VM_BUG_ON_PAGE(!PageLocked(page), page);
309381fe SL	318	VM_BUG_ON_PAGE(PageUptodate(page), page);
93779069 MK	319
	320	/*
	321	* Count submission time as memory stall. When the device is congested,
	322	* or the submitting cgroup IO-throttled, submission can be a
	323	* significant part of overall IO time.
	324	*/
d8c47cc7 JW	325	if (workingset)
d8c47cc7 JW	326	psi_memstall_enter(&pflags);
a3d5dc90	327	delayacct_swapin_start();
93779069	328
165c8aed	329	if (frontswap_load(page) == 0) {
38b5faf4 DM	330	SetPageUptodate(page);
	331	unlock_page(page);
	332	goto out;
	333	}
62c230bc	334
32646315	335	if (data_race(sis->flags & SWP_FS_OPS)) {
62c230bc MG	336	struct file *swap_file = sis->swap_file;
	337	struct address_space *mapping = swap_file->f_mapping;
	338
	339	ret = mapping->a_ops->readpage(swap_file, page);
	340	if (!ret)
	341	count_vm_event(PSWPIN);
93779069	342	goto out;
62c230bc MG	343	}
62c230bc MG	344
5115db10 CH	345	if (sis->flags & SWP_SYNCHRONOUS_IO) {
	346	ret = bdev_read_page(sis->bdev, swap_page_sector(page), page);
	347	if (!ret) {
5115db10 CH	348	count_vm_event(PSWPIN);
	349	goto out;
	350	}
dd6bd0d9 MW	351	}
	352
	353	ret = 0;
07888c66	354	bio = bio_alloc(sis->bdev, 1, REQ_OP_READ, GFP_KERNEL);
48d15436 CH	355	bio->bi_iter.bi_sector = swap_page_sector(page);
	356	bio->bi_end_io = end_swap_bio_read;
	357	bio_add_page(bio, page, thp_size(page), 0);
b0ba2d0f TH	358	/*
	359	* Keep this task valid during swap readpage because the oom killer may
	360	* attempt to access it in the page fault retry time check.
	361	*/
87518530	362	if (synchronous) {
6ce913fe	363	bio->bi_opf \|= REQ_POLLED;
87518530 ON	364	get_task_struct(current);
	365	bio->bi_private = current;
	366	}
f8891e5e	367	count_vm_event(PSWPIN);
23955622	368	bio_get(bio);
3e08773c	369	submit_bio(bio);
0bcac06f	370	while (synchronous) {
1ac5cd49	371	set_current_state(TASK_UNINTERRUPTIBLE);
23955622 SL	372	if (!READ_ONCE(bio->bi_private))
	373	break;
	374
5a72e899	375	if (!bio_poll(bio, NULL, 0))
0f190a7a	376	blk_io_schedule();
23955622 SL	377	}
	378	__set_current_state(TASK_RUNNING);
	379	bio_put(bio);
	380
1da177e4	381	out:
d8c47cc7 JW	382	if (workingset)
d8c47cc7 JW	383	psi_memstall_leave(&pflags);
a3d5dc90	384	delayacct_swapin_end();
1da177e4 LT	385	return ret;
1da177e4 LT	386	}
62c230bc	387
7e63df00	388	bool swap_dirty_folio(struct address_space mapping, struct folio folio)
62c230bc	389	{
7e63df00	390	struct swap_info_struct *sis = swp_swap_info(folio_swap_entry(folio));
62c230bc	391
32646315	392	if (data_race(sis->flags & SWP_FS_OPS)) {
7e63df00 MWO	393	const struct address_space_operations *aops;
	394
	395	mapping = sis->swap_file->f_mapping;
	396	aops = mapping->a_ops;
cc30c5d6	397
7e63df00	398	VM_BUG_ON_FOLIO(!folio_test_swapcache(folio), folio);
3a3bae50	399	return aops->dirty_folio(mapping, folio);
62c230bc	400	} else {
46de8b97	401	return noop_dirty_folio(mapping, folio);
62c230bc MG	402	}
62c230bc MG	403	}