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git.proxmox.com Git - mirror_ubuntu-jammy-kernel.git/blob - mm/page_io.c
4 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
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
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/buffer_head.h>
21 #include <linux/writeback.h>
22 #include <linux/frontswap.h>
23 #include <asm/pgtable.h>
25 static struct bio
*get_swap_bio(gfp_t gfp_flags
,
26 struct page
*page
, bio_end_io_t end_io
)
30 bio
= bio_alloc(gfp_flags
, 1);
32 bio
->bi_sector
= map_swap_page(page
, &bio
->bi_bdev
);
33 bio
->bi_sector
<<= PAGE_SHIFT
- 9;
34 bio
->bi_io_vec
[0].bv_page
= page
;
35 bio
->bi_io_vec
[0].bv_len
= PAGE_SIZE
;
36 bio
->bi_io_vec
[0].bv_offset
= 0;
39 bio
->bi_size
= PAGE_SIZE
;
40 bio
->bi_end_io
= end_io
;
45 static void end_swap_bio_write(struct bio
*bio
, int err
)
47 const int uptodate
= test_bit(BIO_UPTODATE
, &bio
->bi_flags
);
48 struct page
*page
= bio
->bi_io_vec
[0].bv_page
;
53 * We failed to write the page out to swap-space.
54 * Re-dirty the page in order to avoid it being reclaimed.
55 * Also print a dire warning that things will go BAD (tm)
58 * Also clear PG_reclaim to avoid rotate_reclaimable_page()
61 printk(KERN_ALERT
"Write-error on swap-device (%u:%u:%Lu)\n",
62 imajor(bio
->bi_bdev
->bd_inode
),
63 iminor(bio
->bi_bdev
->bd_inode
),
64 (unsigned long long)bio
->bi_sector
);
65 ClearPageReclaim(page
);
67 end_page_writeback(page
);
71 void end_swap_bio_read(struct bio
*bio
, int err
)
73 const int uptodate
= test_bit(BIO_UPTODATE
, &bio
->bi_flags
);
74 struct page
*page
= bio
->bi_io_vec
[0].bv_page
;
78 ClearPageUptodate(page
);
79 printk(KERN_ALERT
"Read-error on swap-device (%u:%u:%Lu)\n",
80 imajor(bio
->bi_bdev
->bd_inode
),
81 iminor(bio
->bi_bdev
->bd_inode
),
82 (unsigned long long)bio
->bi_sector
);
84 SetPageUptodate(page
);
90 int generic_swapfile_activate(struct swap_info_struct
*sis
,
91 struct file
*swap_file
,
94 struct address_space
*mapping
= swap_file
->f_mapping
;
95 struct inode
*inode
= mapping
->host
;
96 unsigned blocks_per_page
;
97 unsigned long page_no
;
101 sector_t lowest_block
= -1;
102 sector_t highest_block
= 0;
106 blkbits
= inode
->i_blkbits
;
107 blocks_per_page
= PAGE_SIZE
>> blkbits
;
110 * Map all the blocks into the extent list. This code doesn't try
115 last_block
= i_size_read(inode
) >> blkbits
;
116 while ((probe_block
+ blocks_per_page
) <= last_block
&&
117 page_no
< sis
->max
) {
118 unsigned block_in_page
;
119 sector_t first_block
;
121 first_block
= bmap(inode
, probe_block
);
122 if (first_block
== 0)
126 * It must be PAGE_SIZE aligned on-disk
128 if (first_block
& (blocks_per_page
- 1)) {
133 for (block_in_page
= 1; block_in_page
< blocks_per_page
;
137 block
= bmap(inode
, probe_block
+ block_in_page
);
140 if (block
!= first_block
+ block_in_page
) {
147 first_block
>>= (PAGE_SHIFT
- blkbits
);
148 if (page_no
) { /* exclude the header page */
149 if (first_block
< lowest_block
)
150 lowest_block
= first_block
;
151 if (first_block
> highest_block
)
152 highest_block
= first_block
;
156 * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks
158 ret
= add_swap_extent(sis
, page_no
, 1, first_block
);
163 probe_block
+= blocks_per_page
;
168 *span
= 1 + highest_block
- lowest_block
;
170 page_no
= 1; /* force Empty message */
172 sis
->pages
= page_no
- 1;
173 sis
->highest_bit
= page_no
- 1;
177 printk(KERN_ERR
"swapon: swapfile has holes\n");
183 * We may have stale swap cache pages in memory: notice
184 * them here and get rid of the unnecessary final write.
186 int swap_writepage(struct page
*page
, struct writeback_control
*wbc
)
189 int ret
= 0, rw
= WRITE
;
190 struct swap_info_struct
*sis
= page_swap_info(page
);
192 if (try_to_free_swap(page
)) {
196 if (frontswap_store(page
) == 0) {
197 set_page_writeback(page
);
199 end_page_writeback(page
);
203 if (sis
->flags
& SWP_FILE
) {
205 struct file
*swap_file
= sis
->swap_file
;
206 struct address_space
*mapping
= swap_file
->f_mapping
;
208 .iov_base
= kmap(page
),
209 .iov_len
= PAGE_SIZE
,
212 init_sync_kiocb(&kiocb
, swap_file
);
213 kiocb
.ki_pos
= page_file_offset(page
);
214 kiocb
.ki_left
= PAGE_SIZE
;
215 kiocb
.ki_nbytes
= PAGE_SIZE
;
218 ret
= mapping
->a_ops
->direct_IO(KERNEL_WRITE
,
222 if (ret
== PAGE_SIZE
) {
223 count_vm_event(PSWPOUT
);
229 bio
= get_swap_bio(GFP_NOIO
, page
, end_swap_bio_write
);
231 set_page_dirty(page
);
236 if (wbc
->sync_mode
== WB_SYNC_ALL
)
238 count_vm_event(PSWPOUT
);
239 set_page_writeback(page
);
246 int swap_readpage(struct page
*page
)
250 struct swap_info_struct
*sis
= page_swap_info(page
);
252 VM_BUG_ON(!PageLocked(page
));
253 VM_BUG_ON(PageUptodate(page
));
254 if (frontswap_load(page
) == 0) {
255 SetPageUptodate(page
);
260 if (sis
->flags
& SWP_FILE
) {
261 struct file
*swap_file
= sis
->swap_file
;
262 struct address_space
*mapping
= swap_file
->f_mapping
;
264 ret
= mapping
->a_ops
->readpage(swap_file
, page
);
266 count_vm_event(PSWPIN
);
270 bio
= get_swap_bio(GFP_KERNEL
, page
, end_swap_bio_read
);
276 count_vm_event(PSWPIN
);
277 submit_bio(READ
, bio
);
282 int swap_set_page_dirty(struct page
*page
)
284 struct swap_info_struct
*sis
= page_swap_info(page
);
286 if (sis
->flags
& SWP_FILE
) {
287 struct address_space
*mapping
= sis
->swap_file
->f_mapping
;
288 return mapping
->a_ops
->set_page_dirty(page
);
290 return __set_page_dirty_no_writeback(page
);