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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/gfp.h>
16#include <linux/pagemap.h>
17#include <linux/swap.h>
18#include <linux/bio.h>
19#include <linux/swapops.h>
20#include <linux/writeback.h>
21#include <asm/pgtable.h>
22
23static struct bio *get_swap_bio(gfp_t gfp_flags,
24 struct page *page, bio_end_io_t end_io)
25{
26 struct bio *bio;
27
28 bio = bio_alloc(gfp_flags, 1);
29 if (bio) {
30 bio->bi_sector = map_swap_page(page, &bio->bi_bdev);
31 bio->bi_sector <<= PAGE_SHIFT - 9;
32 bio->bi_io_vec[0].bv_page = page;
33 bio->bi_io_vec[0].bv_len = PAGE_SIZE;
34 bio->bi_io_vec[0].bv_offset = 0;
35 bio->bi_vcnt = 1;
36 bio->bi_idx = 0;
37 bio->bi_size = PAGE_SIZE;
38 bio->bi_end_io = end_io;
39 }
40 return bio;
41}
42
43static void end_swap_bio_write(struct bio *bio, int err)
44{
45 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
46 struct page *page = bio->bi_io_vec[0].bv_page;
47
48 if (!uptodate) {
49 SetPageError(page);
50 /*
51 * We failed to write the page out to swap-space.
52 * Re-dirty the page in order to avoid it being reclaimed.
53 * Also print a dire warning that things will go BAD (tm)
54 * very quickly.
55 *
56 * Also clear PG_reclaim to avoid rotate_reclaimable_page()
57 */
58 set_page_dirty(page);
59 printk(KERN_ALERT "Write-error on swap-device (%u:%u:%Lu)\n",
60 imajor(bio->bi_bdev->bd_inode),
61 iminor(bio->bi_bdev->bd_inode),
62 (unsigned long long)bio->bi_sector);
63 ClearPageReclaim(page);
64 }
65 end_page_writeback(page);
66 bio_put(bio);
67}
68
69void end_swap_bio_read(struct bio *bio, int err)
70{
71 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
72 struct page *page = bio->bi_io_vec[0].bv_page;
73
74 if (!uptodate) {
75 SetPageError(page);
76 ClearPageUptodate(page);
77 printk(KERN_ALERT "Read-error on swap-device (%u:%u:%Lu)\n",
78 imajor(bio->bi_bdev->bd_inode),
79 iminor(bio->bi_bdev->bd_inode),
80 (unsigned long long)bio->bi_sector);
81 } else {
82 SetPageUptodate(page);
83 }
84 unlock_page(page);
85 bio_put(bio);
86}
87
88/*
89 * We may have stale swap cache pages in memory: notice
90 * them here and get rid of the unnecessary final write.
91 */
92int swap_writepage(struct page *page, struct writeback_control *wbc)
93{
94 struct bio *bio;
95 int ret = 0, rw = WRITE;
96
97 if (try_to_free_swap(page)) {
98 unlock_page(page);
99 goto out;
100 }
101 bio = get_swap_bio(GFP_NOIO, page, end_swap_bio_write);
102 if (bio == NULL) {
103 set_page_dirty(page);
104 unlock_page(page);
105 ret = -ENOMEM;
106 goto out;
107 }
108 if (wbc->sync_mode == WB_SYNC_ALL)
109 rw |= REQ_SYNC;
110 count_vm_event(PSWPOUT);
111 set_page_writeback(page);
112 unlock_page(page);
113 submit_bio(rw, bio);
114out:
115 return ret;
116}
117
118int swap_readpage(struct page *page)
119{
120 struct bio *bio;
121 int ret = 0;
122
123 VM_BUG_ON(!PageLocked(page));
124 VM_BUG_ON(PageUptodate(page));
125 bio = get_swap_bio(GFP_KERNEL, page, end_swap_bio_read);
126 if (bio == NULL) {
127 unlock_page(page);
128 ret = -ENOMEM;
129 goto out;
130 }
131 count_vm_event(PSWPIN);
132 submit_bio(READ, bio);
133out:
134 return ret;
135}
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/gfp.h>
16#include <linux/pagemap.h>
17#include <linux/swap.h>
18#include <linux/bio.h>
19#include <linux/swapops.h>
20#include <linux/writeback.h>
21#include <linux/frontswap.h>
22#include <asm/pgtable.h>
23
24static struct bio *get_swap_bio(gfp_t gfp_flags,
25 struct page *page, bio_end_io_t end_io)
26{
27 struct bio *bio;
28
29 bio = bio_alloc(gfp_flags, 1);
30 if (bio) {
31 bio->bi_sector = map_swap_page(page, &bio->bi_bdev);
32 bio->bi_sector <<= PAGE_SHIFT - 9;
33 bio->bi_io_vec[0].bv_page = page;
34 bio->bi_io_vec[0].bv_len = PAGE_SIZE;
35 bio->bi_io_vec[0].bv_offset = 0;
36 bio->bi_vcnt = 1;
37 bio->bi_idx = 0;
38 bio->bi_size = PAGE_SIZE;
39 bio->bi_end_io = end_io;
40 }
41 return bio;
42}
43
44static void end_swap_bio_write(struct bio *bio, int err)
45{
46 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
47 struct page *page = bio->bi_io_vec[0].bv_page;
48
49 if (!uptodate) {
50 SetPageError(page);
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 }
66 end_page_writeback(page);
67 bio_put(bio);
68}
69
70void end_swap_bio_read(struct bio *bio, int err)
71{
72 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
73 struct page *page = bio->bi_io_vec[0].bv_page;
74
75 if (!uptodate) {
76 SetPageError(page);
77 ClearPageUptodate(page);
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);
82 } else {
83 SetPageUptodate(page);
84 }
85 unlock_page(page);
86 bio_put(bio);
87}
88
89/*
90 * We may have stale swap cache pages in memory: notice
91 * them here and get rid of the unnecessary final write.
92 */
93int swap_writepage(struct page *page, struct writeback_control *wbc)
94{
95 struct bio *bio;
96 int ret = 0, rw = WRITE;
97
98 if (try_to_free_swap(page)) {
99 unlock_page(page);
100 goto out;
101 }
102 if (frontswap_store(page) == 0) {
103 set_page_writeback(page);
104 unlock_page(page);
105 end_page_writeback(page);
106 goto out;
107 }
108 bio = get_swap_bio(GFP_NOIO, page, end_swap_bio_write);
109 if (bio == NULL) {
110 set_page_dirty(page);
111 unlock_page(page);
112 ret = -ENOMEM;
113 goto out;
114 }
115 if (wbc->sync_mode == WB_SYNC_ALL)
116 rw |= REQ_SYNC;
117 count_vm_event(PSWPOUT);
118 set_page_writeback(page);
119 unlock_page(page);
120 submit_bio(rw, bio);
121out:
122 return ret;
123}
124
125int swap_readpage(struct page *page)
126{
127 struct bio *bio;
128 int ret = 0;
129
130 VM_BUG_ON(!PageLocked(page));
131 VM_BUG_ON(PageUptodate(page));
132 if (frontswap_load(page) == 0) {
133 SetPageUptodate(page);
134 unlock_page(page);
135 goto out;
136 }
137 bio = get_swap_bio(GFP_KERNEL, page, end_swap_bio_read);
138 if (bio == NULL) {
139 unlock_page(page);
140 ret = -ENOMEM;
141 goto out;
142 }
143 count_vm_event(PSWPIN);
144 submit_bio(READ, bio);
145out:
146 return ret;
147}