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git.proxmox.com Git - mirror_ubuntu-bionic-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;
38 bio
->bi_size
= PAGE_SIZE
;
39 bio
->bi_end_io
= end_io
;
44 static void end_swap_bio_write(struct bio
*bio
, int err
)
46 const int uptodate
= test_bit(BIO_UPTODATE
, &bio
->bi_flags
);
47 struct page
*page
= bio
->bi_io_vec
[0].bv_page
;
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)
57 * Also clear PG_reclaim to avoid rotate_reclaimable_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
);
66 end_page_writeback(page
);
70 void end_swap_bio_read(struct bio
*bio
, int err
)
72 const int uptodate
= test_bit(BIO_UPTODATE
, &bio
->bi_flags
);
73 struct page
*page
= bio
->bi_io_vec
[0].bv_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
);
83 SetPageUptodate(page
);
89 int generic_swapfile_activate(struct swap_info_struct
*sis
,
90 struct file
*swap_file
,
93 struct address_space
*mapping
= swap_file
->f_mapping
;
94 struct inode
*inode
= mapping
->host
;
95 unsigned blocks_per_page
;
96 unsigned long page_no
;
100 sector_t lowest_block
= -1;
101 sector_t highest_block
= 0;
105 blkbits
= inode
->i_blkbits
;
106 blocks_per_page
= PAGE_SIZE
>> blkbits
;
109 * Map all the blocks into the extent list. This code doesn't try
114 last_block
= i_size_read(inode
) >> blkbits
;
115 while ((probe_block
+ blocks_per_page
) <= last_block
&&
116 page_no
< sis
->max
) {
117 unsigned block_in_page
;
118 sector_t first_block
;
120 first_block
= bmap(inode
, probe_block
);
121 if (first_block
== 0)
125 * It must be PAGE_SIZE aligned on-disk
127 if (first_block
& (blocks_per_page
- 1)) {
132 for (block_in_page
= 1; block_in_page
< blocks_per_page
;
136 block
= bmap(inode
, probe_block
+ block_in_page
);
139 if (block
!= first_block
+ block_in_page
) {
146 first_block
>>= (PAGE_SHIFT
- blkbits
);
147 if (page_no
) { /* exclude the header page */
148 if (first_block
< lowest_block
)
149 lowest_block
= first_block
;
150 if (first_block
> highest_block
)
151 highest_block
= first_block
;
155 * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks
157 ret
= add_swap_extent(sis
, page_no
, 1, first_block
);
162 probe_block
+= blocks_per_page
;
167 *span
= 1 + highest_block
- lowest_block
;
169 page_no
= 1; /* force Empty message */
171 sis
->pages
= page_no
- 1;
172 sis
->highest_bit
= page_no
- 1;
176 printk(KERN_ERR
"swapon: swapfile has holes\n");
182 * We may have stale swap cache pages in memory: notice
183 * them here and get rid of the unnecessary final write.
185 int swap_writepage(struct page
*page
, struct writeback_control
*wbc
)
188 int ret
= 0, rw
= WRITE
;
189 struct swap_info_struct
*sis
= page_swap_info(page
);
191 if (try_to_free_swap(page
)) {
195 if (frontswap_store(page
) == 0) {
196 set_page_writeback(page
);
198 end_page_writeback(page
);
202 if (sis
->flags
& SWP_FILE
) {
204 struct file
*swap_file
= sis
->swap_file
;
205 struct address_space
*mapping
= swap_file
->f_mapping
;
207 .iov_base
= kmap(page
),
208 .iov_len
= PAGE_SIZE
,
211 init_sync_kiocb(&kiocb
, swap_file
);
212 kiocb
.ki_pos
= page_file_offset(page
);
213 kiocb
.ki_left
= PAGE_SIZE
;
214 kiocb
.ki_nbytes
= PAGE_SIZE
;
217 ret
= mapping
->a_ops
->direct_IO(KERNEL_WRITE
,
221 if (ret
== PAGE_SIZE
) {
222 count_vm_event(PSWPOUT
);
228 bio
= get_swap_bio(GFP_NOIO
, page
, end_swap_bio_write
);
230 set_page_dirty(page
);
235 if (wbc
->sync_mode
== WB_SYNC_ALL
)
237 count_vm_event(PSWPOUT
);
238 set_page_writeback(page
);
245 int swap_readpage(struct page
*page
)
249 struct swap_info_struct
*sis
= page_swap_info(page
);
251 VM_BUG_ON(!PageLocked(page
));
252 VM_BUG_ON(PageUptodate(page
));
253 if (frontswap_load(page
) == 0) {
254 SetPageUptodate(page
);
259 if (sis
->flags
& SWP_FILE
) {
260 struct file
*swap_file
= sis
->swap_file
;
261 struct address_space
*mapping
= swap_file
->f_mapping
;
263 ret
= mapping
->a_ops
->readpage(swap_file
, page
);
265 count_vm_event(PSWPIN
);
269 bio
= get_swap_bio(GFP_KERNEL
, page
, end_swap_bio_read
);
275 count_vm_event(PSWPIN
);
276 submit_bio(READ
, bio
);
281 int swap_set_page_dirty(struct page
*page
)
283 struct swap_info_struct
*sis
= page_swap_info(page
);
285 if (sis
->flags
& SWP_FILE
) {
286 struct address_space
*mapping
= sis
->swap_file
->f_mapping
;
287 return mapping
->a_ops
->set_page_dirty(page
);
289 return __set_page_dirty_no_writeback(page
);