swapfile.c (9d4d8572a539ef807e21c196f145aa365fd52f0e) swapfile.c (f885056a48ccf4ad4332def91e973f3993fa8695)
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/mm/swapfile.c
4 *
5 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
6 * Swap reorganised 29.12.95, Stephen Tweedie
7 */
8

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42
43#include <asm/tlbflush.h>
44#include <linux/swapops.h>
45#include <linux/swap_cgroup.h>
46
47static bool swap_count_continued(struct swap_info_struct *, pgoff_t,
48 unsigned char);
49static void free_swap_count_continuations(struct swap_info_struct *);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/mm/swapfile.c
4 *
5 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
6 * Swap reorganised 29.12.95, Stephen Tweedie
7 */
8

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42
43#include <asm/tlbflush.h>
44#include <linux/swapops.h>
45#include <linux/swap_cgroup.h>
46
47static bool swap_count_continued(struct swap_info_struct *, pgoff_t,
48 unsigned char);
49static void free_swap_count_continuations(struct swap_info_struct *);
50static sector_t map_swap_entry(swp_entry_t, struct block_device**);
51
52DEFINE_SPINLOCK(swap_lock);
53static unsigned int nr_swapfiles;
54atomic_long_t nr_swap_pages;
55/*
56 * Some modules use swappable objects and may try to swap them out under
57 * memory pressure (via the shrinker). Before doing so, they may wish to
58 * check to see if any swap space is available.

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1845}
1846
1847/*
1848 * Get the (PAGE_SIZE) block corresponding to given offset on the swapdev
1849 * corresponding to given index in swap_info (swap type).
1850 */
1851sector_t swapdev_block(int type, pgoff_t offset)
1852{
50
51DEFINE_SPINLOCK(swap_lock);
52static unsigned int nr_swapfiles;
53atomic_long_t nr_swap_pages;
54/*
55 * Some modules use swappable objects and may try to swap them out under
56 * memory pressure (via the shrinker). Before doing so, they may wish to
57 * check to see if any swap space is available.

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1844}
1845
1846/*
1847 * Get the (PAGE_SIZE) block corresponding to given offset on the swapdev
1848 * corresponding to given index in swap_info (swap type).
1849 */
1850sector_t swapdev_block(int type, pgoff_t offset)
1851{
1853 struct block_device *bdev;
1854 struct swap_info_struct *si = swap_type_to_swap_info(type);
1852 struct swap_info_struct *si = swap_type_to_swap_info(type);
1853 struct swap_extent *se;
1855
1856 if (!si || !(si->flags & SWP_WRITEOK))
1857 return 0;
1854
1855 if (!si || !(si->flags & SWP_WRITEOK))
1856 return 0;
1858 return map_swap_entry(swp_entry(type, offset), &bdev);
1857 se = offset_to_swap_extent(si, offset);
1858 return se->start_block + (offset - se->start_page);
1859}
1860
1861/*
1862 * Return either the total number of swap pages of given type, or the number
1863 * of free pages of that type (depending on @free)
1864 *
1865 * This is needed for software suspend
1866 */

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2277 return;
2278 spin_lock(&mmlist_lock);
2279 list_for_each_safe(p, next, &init_mm.mmlist)
2280 list_del_init(p);
2281 spin_unlock(&mmlist_lock);
2282}
2283
2284/*
1859}
1860
1861/*
1862 * Return either the total number of swap pages of given type, or the number
1863 * of free pages of that type (depending on @free)
1864 *
1865 * This is needed for software suspend
1866 */

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2277 return;
2278 spin_lock(&mmlist_lock);
2279 list_for_each_safe(p, next, &init_mm.mmlist)
2280 list_del_init(p);
2281 spin_unlock(&mmlist_lock);
2282}
2283
2284/*
2285 * Use this swapdev's extent info to locate the (PAGE_SIZE) block which
2286 * corresponds to page offset for the specified swap entry.
2287 * Note that the type of this function is sector_t, but it returns page offset
2288 * into the bdev, not sector offset.
2289 */
2290static sector_t map_swap_entry(swp_entry_t entry, struct block_device **bdev)
2291{
2292 struct swap_info_struct *sis;
2293 struct swap_extent *se;
2294 pgoff_t offset;
2295
2296 sis = swp_swap_info(entry);
2297 *bdev = sis->bdev;
2298
2299 offset = swp_offset(entry);
2300 se = offset_to_swap_extent(sis, offset);
2301 return se->start_block + (offset - se->start_page);
2302}
2303
2304/*
2305 * Returns the page offset into bdev for the specified page's swap entry.
2306 */
2307sector_t map_swap_page(struct page *page, struct block_device **bdev)
2308{
2309 swp_entry_t entry;
2310 entry.val = page_private(page);
2311 return map_swap_entry(entry, bdev);
2312}
2313
2314/*
2315 * Free all of a swapdev's extent information
2316 */
2317static void destroy_swap_extents(struct swap_info_struct *sis)
2318{
2319 while (!RB_EMPTY_ROOT(&sis->swap_extent_root)) {
2320 struct rb_node *rb = sis->swap_extent_root.rb_node;
2321 struct swap_extent *se = rb_entry(rb, struct swap_extent, rb_node);
2322

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2286 */
2287static void destroy_swap_extents(struct swap_info_struct *sis)
2288{
2289 while (!RB_EMPTY_ROOT(&sis->swap_extent_root)) {
2290 struct rb_node *rb = sis->swap_extent_root.rb_node;
2291 struct swap_extent *se = rb_entry(rb, struct swap_extent, rb_node);
2292

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