ia64/linux-2.6.18-xen.hg

view mm/page_io.c @ 912:dd42cdb0ab89

[IA64] Build blktap2 driver by default in x86 builds.

add CONFIG_XEN_BLKDEV_TAP2=y to buildconfigs/linux-defconfig_xen_ia64.

Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
author Isaku Yamahata <yamahata@valinux.co.jp>
date Mon Jun 29 12:09:16 2009 +0900 (2009-06-29)
parents cad6f60f0506
children
line source
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 */
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>
22 static struct bio *get_swap_bio(gfp_t gfp_flags, pgoff_t index,
23 struct page *page, bio_end_io_t end_io)
24 {
25 struct bio *bio;
27 bio = bio_alloc(gfp_flags, 1);
28 if (bio) {
29 struct swap_info_struct *sis;
30 swp_entry_t entry = { .val = index, };
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 }
47 static 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;
52 if (bio->bi_size)
53 return 1;
55 if (!uptodate)
56 SetPageError(page);
57 end_page_writeback(page);
58 bio_put(bio);
59 return 0;
60 }
62 static int end_swap_bio_read(struct bio *bio, unsigned int bytes_done, int err)
63 {
64 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
65 struct page *page = bio->bi_io_vec[0].bv_page;
67 if (bio->bi_size)
68 return 1;
70 if (!uptodate) {
71 SetPageError(page);
72 ClearPageUptodate(page);
73 } else {
74 SetPageUptodate(page);
75 }
76 unlock_page(page);
77 bio_put(bio);
78 return 0;
79 }
81 /*
82 * We may have stale swap cache pages in memory: notice
83 * them here and get rid of the unnecessary final write.
84 */
85 int swap_writepage(struct page *page, struct writeback_control *wbc)
86 {
87 struct bio *bio;
88 int ret = 0, rw = WRITE;
90 if (remove_exclusive_swap_page(page)) {
91 unlock_page(page);
92 goto out;
93 }
94 bio = get_swap_bio(GFP_NOIO, page_private(page), page,
95 end_swap_bio_write);
96 if (bio == NULL) {
97 set_page_dirty(page);
98 unlock_page(page);
99 ret = -ENOMEM;
100 goto out;
101 }
103 set_page_writeback(page);
104 if (preswap_put(page) == 1) {
105 unlock_page(page);
106 end_page_writeback(page);
107 bio_put(bio);
108 goto out;
109 }
111 if (wbc->sync_mode == WB_SYNC_ALL)
112 rw |= (1 << BIO_RW_SYNC);
113 count_vm_event(PSWPOUT);
114 unlock_page(page);
115 submit_bio(rw, bio);
116 out:
117 return ret;
118 }
120 int swap_readpage(struct file *file, struct page *page)
121 {
122 struct bio *bio;
123 int ret = 0;
125 BUG_ON(!PageLocked(page));
126 ClearPageUptodate(page);
128 if (preswap_get(page) == 1) {
129 SetPageUptodate(page);
130 unlock_page(page);
131 goto out;
132 }
134 bio = get_swap_bio(GFP_KERNEL, page_private(page), page,
135 end_swap_bio_read);
136 if (bio == NULL) {
137 unlock_page(page);
138 ret = -ENOMEM;
139 goto out;
140 }
141 count_vm_event(PSWPIN);
142 submit_bio(READ, bio);
143 out:
144 return ret;
145 }
147 #ifdef CONFIG_SOFTWARE_SUSPEND
148 /*
149 * A scruffy utility function to read or write an arbitrary swap page
150 * and wait on the I/O. The caller must have a ref on the page.
151 *
152 * We use end_swap_bio_read() even for writes, because it happens to do what
153 * we want.
154 */
155 int rw_swap_page_sync(int rw, swp_entry_t entry, struct page *page)
156 {
157 struct bio *bio;
158 int ret = 0;
160 lock_page(page);
162 bio = get_swap_bio(GFP_KERNEL, entry.val, page, end_swap_bio_read);
163 if (bio == NULL) {
164 unlock_page(page);
165 ret = -ENOMEM;
166 goto out;
167 }
169 submit_bio(rw | (1 << BIO_RW_SYNC), bio);
170 wait_on_page_locked(page);
172 if (!PageUptodate(page) || PageError(page))
173 ret = -EIO;
174 out:
175 return ret;
176 }
177 #endif