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 | ||
f29ad6a9 | 22 | static struct bio *get_swap_bio(gfp_t gfp_flags, |
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) { | |
d4906e1a | 29 | bio->bi_sector = map_swap_page(page, &bio->bi_bdev); |
f29ad6a9 | 30 | bio->bi_sector <<= PAGE_SHIFT - 9; |
1da177e4 LT |
31 | bio->bi_io_vec[0].bv_page = page; |
32 | bio->bi_io_vec[0].bv_len = PAGE_SIZE; | |
33 | bio->bi_io_vec[0].bv_offset = 0; | |
34 | bio->bi_vcnt = 1; | |
35 | bio->bi_idx = 0; | |
36 | bio->bi_size = PAGE_SIZE; | |
37 | bio->bi_end_io = end_io; | |
38 | } | |
39 | return bio; | |
40 | } | |
41 | ||
6712ecf8 | 42 | static void end_swap_bio_write(struct bio *bio, int err) |
1da177e4 LT |
43 | { |
44 | const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); | |
45 | struct page *page = bio->bi_io_vec[0].bv_page; | |
46 | ||
6ddab3b9 | 47 | if (!uptodate) { |
1da177e4 | 48 | SetPageError(page); |
6ddab3b9 PZ |
49 | /* |
50 | * We failed to write the page out to swap-space. | |
51 | * Re-dirty the page in order to avoid it being reclaimed. | |
52 | * Also print a dire warning that things will go BAD (tm) | |
53 | * very quickly. | |
54 | * | |
55 | * Also clear PG_reclaim to avoid rotate_reclaimable_page() | |
56 | */ | |
57 | set_page_dirty(page); | |
58 | printk(KERN_ALERT "Write-error on swap-device (%u:%u:%Lu)\n", | |
59 | imajor(bio->bi_bdev->bd_inode), | |
60 | iminor(bio->bi_bdev->bd_inode), | |
61 | (unsigned long long)bio->bi_sector); | |
62 | ClearPageReclaim(page); | |
63 | } | |
1da177e4 LT |
64 | end_page_writeback(page); |
65 | bio_put(bio); | |
1da177e4 LT |
66 | } |
67 | ||
6712ecf8 | 68 | void end_swap_bio_read(struct bio *bio, int err) |
1da177e4 LT |
69 | { |
70 | const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); | |
71 | struct page *page = bio->bi_io_vec[0].bv_page; | |
72 | ||
1da177e4 LT |
73 | if (!uptodate) { |
74 | SetPageError(page); | |
75 | ClearPageUptodate(page); | |
6ddab3b9 PZ |
76 | printk(KERN_ALERT "Read-error on swap-device (%u:%u:%Lu)\n", |
77 | imajor(bio->bi_bdev->bd_inode), | |
78 | iminor(bio->bi_bdev->bd_inode), | |
79 | (unsigned long long)bio->bi_sector); | |
1da177e4 LT |
80 | } else { |
81 | SetPageUptodate(page); | |
82 | } | |
83 | unlock_page(page); | |
84 | bio_put(bio); | |
1da177e4 LT |
85 | } |
86 | ||
87 | /* | |
88 | * We may have stale swap cache pages in memory: notice | |
89 | * them here and get rid of the unnecessary final write. | |
90 | */ | |
91 | int swap_writepage(struct page *page, struct writeback_control *wbc) | |
92 | { | |
93 | struct bio *bio; | |
94 | int ret = 0, rw = WRITE; | |
95 | ||
a2c43eed | 96 | if (try_to_free_swap(page)) { |
1da177e4 LT |
97 | unlock_page(page); |
98 | goto out; | |
99 | } | |
f29ad6a9 | 100 | bio = get_swap_bio(GFP_NOIO, page, end_swap_bio_write); |
1da177e4 LT |
101 | if (bio == NULL) { |
102 | set_page_dirty(page); | |
103 | unlock_page(page); | |
104 | ret = -ENOMEM; | |
105 | goto out; | |
106 | } | |
107 | if (wbc->sync_mode == WB_SYNC_ALL) | |
93dbb393 | 108 | rw |= (1 << BIO_RW_SYNCIO) | (1 << BIO_RW_UNPLUG); |
f8891e5e | 109 | count_vm_event(PSWPOUT); |
1da177e4 LT |
110 | set_page_writeback(page); |
111 | unlock_page(page); | |
112 | submit_bio(rw, bio); | |
113 | out: | |
114 | return ret; | |
115 | } | |
116 | ||
aca8bf32 | 117 | int swap_readpage(struct page *page) |
1da177e4 LT |
118 | { |
119 | struct bio *bio; | |
120 | int ret = 0; | |
121 | ||
51726b12 HD |
122 | VM_BUG_ON(!PageLocked(page)); |
123 | VM_BUG_ON(PageUptodate(page)); | |
f29ad6a9 | 124 | bio = get_swap_bio(GFP_KERNEL, page, end_swap_bio_read); |
1da177e4 LT |
125 | if (bio == NULL) { |
126 | unlock_page(page); | |
127 | ret = -ENOMEM; | |
128 | goto out; | |
129 | } | |
f8891e5e | 130 | count_vm_event(PSWPIN); |
1da177e4 LT |
131 | submit_bio(READ, bio); |
132 | out: | |
133 | return ret; | |
134 | } |