blob: d4840ecbf8f9358e1dfc5918802f3604e1f06b93 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Al Virodd0fc662005-10-07 07:46:04 +010022static struct bio *get_swap_bio(gfp_t gfp_flags, pgoff_t index,
Linus Torvalds1da177e2005-04-16 15:20:36 -070023 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) {
29 struct swap_info_struct *sis;
30 swp_entry_t entry = { .val = index, };
31
32 sis = get_swap_info_struct(swp_type(entry));
33 bio->bi_sector = map_swap_page(sis, swp_offset(entry)) *
34 (PAGE_SIZE >> 9);
35 bio->bi_bdev = sis->bdev;
36 bio->bi_io_vec[0].bv_page = page;
37 bio->bi_io_vec[0].bv_len = PAGE_SIZE;
38 bio->bi_io_vec[0].bv_offset = 0;
39 bio->bi_vcnt = 1;
40 bio->bi_idx = 0;
41 bio->bi_size = PAGE_SIZE;
42 bio->bi_end_io = end_io;
43 }
44 return bio;
45}
46
47static int end_swap_bio_write(struct bio *bio, unsigned int bytes_done, int err)
48{
49 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
50 struct page *page = bio->bi_io_vec[0].bv_page;
51
52 if (bio->bi_size)
53 return 1;
54
Peter Zijlstra6ddab3b2006-09-25 23:31:26 -070055 if (!uptodate) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070056 SetPageError(page);
Peter Zijlstra6ddab3b2006-09-25 23:31:26 -070057 /*
58 * We failed to write the page out to swap-space.
59 * Re-dirty the page in order to avoid it being reclaimed.
60 * Also print a dire warning that things will go BAD (tm)
61 * very quickly.
62 *
63 * Also clear PG_reclaim to avoid rotate_reclaimable_page()
64 */
65 set_page_dirty(page);
66 printk(KERN_ALERT "Write-error on swap-device (%u:%u:%Lu)\n",
67 imajor(bio->bi_bdev->bd_inode),
68 iminor(bio->bi_bdev->bd_inode),
69 (unsigned long long)bio->bi_sector);
70 ClearPageReclaim(page);
71 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070072 end_page_writeback(page);
73 bio_put(bio);
74 return 0;
75}
76
Andrew Morton546e0d22006-09-25 23:32:44 -070077int end_swap_bio_read(struct bio *bio, unsigned int bytes_done, int err)
Linus Torvalds1da177e2005-04-16 15:20:36 -070078{
79 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
80 struct page *page = bio->bi_io_vec[0].bv_page;
81
82 if (bio->bi_size)
83 return 1;
84
85 if (!uptodate) {
86 SetPageError(page);
87 ClearPageUptodate(page);
Peter Zijlstra6ddab3b2006-09-25 23:31:26 -070088 printk(KERN_ALERT "Read-error on swap-device (%u:%u:%Lu)\n",
89 imajor(bio->bi_bdev->bd_inode),
90 iminor(bio->bi_bdev->bd_inode),
91 (unsigned long long)bio->bi_sector);
Linus Torvalds1da177e2005-04-16 15:20:36 -070092 } else {
93 SetPageUptodate(page);
94 }
95 unlock_page(page);
96 bio_put(bio);
97 return 0;
98}
99
100/*
101 * We may have stale swap cache pages in memory: notice
102 * them here and get rid of the unnecessary final write.
103 */
104int swap_writepage(struct page *page, struct writeback_control *wbc)
105{
106 struct bio *bio;
107 int ret = 0, rw = WRITE;
108
109 if (remove_exclusive_swap_page(page)) {
110 unlock_page(page);
111 goto out;
112 }
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700113 bio = get_swap_bio(GFP_NOIO, page_private(page), page,
114 end_swap_bio_write);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115 if (bio == NULL) {
116 set_page_dirty(page);
117 unlock_page(page);
118 ret = -ENOMEM;
119 goto out;
120 }
121 if (wbc->sync_mode == WB_SYNC_ALL)
122 rw |= (1 << BIO_RW_SYNC);
Christoph Lameterf8891e52006-06-30 01:55:45 -0700123 count_vm_event(PSWPOUT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124 set_page_writeback(page);
125 unlock_page(page);
126 submit_bio(rw, bio);
127out:
128 return ret;
129}
130
131int swap_readpage(struct file *file, struct page *page)
132{
133 struct bio *bio;
134 int ret = 0;
135
136 BUG_ON(!PageLocked(page));
137 ClearPageUptodate(page);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700138 bio = get_swap_bio(GFP_KERNEL, page_private(page), page,
139 end_swap_bio_read);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 if (bio == NULL) {
141 unlock_page(page);
142 ret = -ENOMEM;
143 goto out;
144 }
Christoph Lameterf8891e52006-06-30 01:55:45 -0700145 count_vm_event(PSWPIN);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 submit_bio(READ, bio);
147out:
148 return ret;
149}
150
Pavel Machek648be312005-06-25 14:55:09 -0700151#ifdef CONFIG_SOFTWARE_SUSPEND
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152/*
153 * A scruffy utility function to read or write an arbitrary swap page
154 * and wait on the I/O. The caller must have a ref on the page.
155 *
156 * We use end_swap_bio_read() even for writes, because it happens to do what
157 * we want.
158 */
Andrew Mortonab954162006-09-25 23:32:42 -0700159int rw_swap_page_sync(int rw, swp_entry_t entry, struct page *page,
160 struct bio **bio_chain)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161{
162 struct bio *bio;
163 int ret = 0;
Andrew Mortonab954162006-09-25 23:32:42 -0700164 int bio_rw;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165
166 lock_page(page);
167
168 bio = get_swap_bio(GFP_KERNEL, entry.val, page, end_swap_bio_read);
169 if (bio == NULL) {
170 unlock_page(page);
171 ret = -ENOMEM;
172 goto out;
173 }
174
Andrew Mortonab954162006-09-25 23:32:42 -0700175 bio_rw = rw;
176 if (!bio_chain)
177 bio_rw |= (1 << BIO_RW_SYNC);
178 if (bio_chain)
179 bio_get(bio);
180 submit_bio(bio_rw, bio);
181 if (bio_chain == NULL) {
182 wait_on_page_locked(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183
Andrew Mortonab954162006-09-25 23:32:42 -0700184 if (!PageUptodate(page) || PageError(page))
185 ret = -EIO;
186 }
187 if (bio_chain) {
188 bio->bi_private = *bio_chain;
189 *bio_chain = bio;
190 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191out:
192 return ret;
193}
194#endif