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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/buffer_head.h>
21#include <linux/writeback.h>
22#include <linux/frontswap.h>
23#include <linux/aio.h>
24#include <linux/blkdev.h>
25#include <asm/pgtable.h>
26
27static struct bio *get_swap_bio(gfp_t gfp_flags,
28 struct page *page, bio_end_io_t end_io)
29{
30 struct bio *bio;
31
32 bio = bio_alloc(gfp_flags, 1);
33 if (bio) {
34 bio->bi_sector = map_swap_page(page, &bio->bi_bdev);
35 bio->bi_sector <<= PAGE_SHIFT - 9;
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_size = PAGE_SIZE;
41 bio->bi_end_io = end_io;
42 }
43 return bio;
44}
45
46void end_swap_bio_write(struct bio *bio, int err)
47{
48 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
49 struct page *page = bio->bi_io_vec[0].bv_page;
50
51 if (!uptodate) {
52 SetPageError(page);
53
54
55
56
57
58
59
60
61 set_page_dirty(page);
62 printk(KERN_ALERT "Write-error on swap-device (%u:%u:%Lu)\n",
63 imajor(bio->bi_bdev->bd_inode),
64 iminor(bio->bi_bdev->bd_inode),
65 (unsigned long long)bio->bi_sector);
66 ClearPageReclaim(page);
67 }
68 end_page_writeback(page);
69 bio_put(bio);
70}
71
72void end_swap_bio_read(struct bio *bio, int err)
73{
74 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
75 struct page *page = bio->bi_io_vec[0].bv_page;
76
77 if (!uptodate) {
78 SetPageError(page);
79 ClearPageUptodate(page);
80 printk(KERN_ALERT "Read-error on swap-device (%u:%u:%Lu)\n",
81 imajor(bio->bi_bdev->bd_inode),
82 iminor(bio->bi_bdev->bd_inode),
83 (unsigned long long)bio->bi_sector);
84 goto out;
85 }
86
87 SetPageUptodate(page);
88
89
90
91
92
93
94
95 if (likely(PageSwapCache(page))) {
96 struct swap_info_struct *sis;
97
98 sis = page_swap_info(page);
99 if (sis->flags & SWP_BLKDEV) {
100
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111
112
113
114
115
116 struct gendisk *disk = sis->bdev->bd_disk;
117 if (disk->fops->swap_slot_free_notify) {
118 swp_entry_t entry;
119 unsigned long offset;
120
121 entry.val = page_private(page);
122 offset = swp_offset(entry);
123
124 SetPageDirty(page);
125 disk->fops->swap_slot_free_notify(sis->bdev,
126 offset);
127 }
128 }
129 }
130
131out:
132 unlock_page(page);
133 bio_put(bio);
134}
135
136int generic_swapfile_activate(struct swap_info_struct *sis,
137 struct file *swap_file,
138 sector_t *span)
139{
140 struct address_space *mapping = swap_file->f_mapping;
141 struct inode *inode = mapping->host;
142 unsigned blocks_per_page;
143 unsigned long page_no;
144 unsigned blkbits;
145 sector_t probe_block;
146 sector_t last_block;
147 sector_t lowest_block = -1;
148 sector_t highest_block = 0;
149 int nr_extents = 0;
150 int ret;
151
152 blkbits = inode->i_blkbits;
153 blocks_per_page = PAGE_SIZE >> blkbits;
154
155
156
157
158
159 probe_block = 0;
160 page_no = 0;
161 last_block = i_size_read(inode) >> blkbits;
162 while ((probe_block + blocks_per_page) <= last_block &&
163 page_no < sis->max) {
164 unsigned block_in_page;
165 sector_t first_block;
166
167 first_block = bmap(inode, probe_block);
168 if (first_block == 0)
169 goto bad_bmap;
170
171
172
173
174 if (first_block & (blocks_per_page - 1)) {
175 probe_block++;
176 goto reprobe;
177 }
178
179 for (block_in_page = 1; block_in_page < blocks_per_page;
180 block_in_page++) {
181 sector_t block;
182
183 block = bmap(inode, probe_block + block_in_page);
184 if (block == 0)
185 goto bad_bmap;
186 if (block != first_block + block_in_page) {
187
188 probe_block++;
189 goto reprobe;
190 }
191 }
192
193 first_block >>= (PAGE_SHIFT - blkbits);
194 if (page_no) {
195 if (first_block < lowest_block)
196 lowest_block = first_block;
197 if (first_block > highest_block)
198 highest_block = first_block;
199 }
200
201
202
203
204 ret = add_swap_extent(sis, page_no, 1, first_block);
205 if (ret < 0)
206 goto out;
207 nr_extents += ret;
208 page_no++;
209 probe_block += blocks_per_page;
210reprobe:
211 continue;
212 }
213 ret = nr_extents;
214 *span = 1 + highest_block - lowest_block;
215 if (page_no == 0)
216 page_no = 1;
217 sis->max = page_no;
218 sis->pages = page_no - 1;
219 sis->highest_bit = page_no - 1;
220out:
221 return ret;
222bad_bmap:
223 printk(KERN_ERR "swapon: swapfile has holes\n");
224 ret = -EINVAL;
225 goto out;
226}
227
228
229
230
231
232int swap_writepage(struct page *page, struct writeback_control *wbc)
233{
234 int ret = 0;
235
236 if (try_to_free_swap(page)) {
237 unlock_page(page);
238 goto out;
239 }
240 if (frontswap_store(page) == 0) {
241 set_page_writeback(page);
242 unlock_page(page);
243 end_page_writeback(page);
244 goto out;
245 }
246 ret = __swap_writepage(page, wbc, end_swap_bio_write);
247out:
248 return ret;
249}
250
251int __swap_writepage(struct page *page, struct writeback_control *wbc,
252 void (*end_write_func)(struct bio *, int))
253{
254 struct bio *bio;
255 int ret = 0, rw = WRITE;
256 struct swap_info_struct *sis = page_swap_info(page);
257
258 if (sis->flags & SWP_FILE) {
259 struct kiocb kiocb;
260 struct file *swap_file = sis->swap_file;
261 struct address_space *mapping = swap_file->f_mapping;
262 struct iovec iov = {
263 .iov_base = kmap(page),
264 .iov_len = PAGE_SIZE,
265 };
266
267 init_sync_kiocb(&kiocb, swap_file);
268 kiocb.ki_pos = page_file_offset(page);
269 kiocb.ki_left = PAGE_SIZE;
270 kiocb.ki_nbytes = PAGE_SIZE;
271
272 set_page_writeback(page);
273 unlock_page(page);
274 ret = mapping->a_ops->direct_IO(KERNEL_WRITE,
275 &kiocb, &iov,
276 kiocb.ki_pos, 1);
277 kunmap(page);
278 if (ret == PAGE_SIZE) {
279 count_vm_event(PSWPOUT);
280 ret = 0;
281 } else {
282
283
284
285
286
287
288
289
290
291
292 set_page_dirty(page);
293 ClearPageReclaim(page);
294 pr_err_ratelimited("Write error on dio swapfile (%Lu)\n",
295 page_file_offset(page));
296 }
297 end_page_writeback(page);
298 return ret;
299 }
300
301 bio = get_swap_bio(GFP_NOIO, page, end_write_func);
302 if (bio == NULL) {
303 set_page_dirty(page);
304 unlock_page(page);
305 ret = -ENOMEM;
306 goto out;
307 }
308 if (wbc->sync_mode == WB_SYNC_ALL)
309 rw |= REQ_SYNC;
310 count_vm_event(PSWPOUT);
311 set_page_writeback(page);
312 unlock_page(page);
313 submit_bio(rw, bio);
314out:
315 return ret;
316}
317
318int swap_readpage(struct page *page)
319{
320 struct bio *bio;
321 int ret = 0;
322 struct swap_info_struct *sis = page_swap_info(page);
323
324 VM_BUG_ON(!PageLocked(page));
325 VM_BUG_ON(PageUptodate(page));
326 if (frontswap_load(page) == 0) {
327 SetPageUptodate(page);
328 unlock_page(page);
329 goto out;
330 }
331
332 if (sis->flags & SWP_FILE) {
333 struct file *swap_file = sis->swap_file;
334 struct address_space *mapping = swap_file->f_mapping;
335
336 ret = mapping->a_ops->readpage(swap_file, page);
337 if (!ret)
338 count_vm_event(PSWPIN);
339 return ret;
340 }
341
342 bio = get_swap_bio(GFP_KERNEL, page, end_swap_bio_read);
343 if (bio == NULL) {
344 unlock_page(page);
345 ret = -ENOMEM;
346 goto out;
347 }
348 count_vm_event(PSWPIN);
349 submit_bio(READ, bio);
350out:
351 return ret;
352}
353
354int swap_set_page_dirty(struct page *page)
355{
356 struct swap_info_struct *sis = page_swap_info(page);
357
358 if (sis->flags & SWP_FILE) {
359 struct address_space *mapping = sis->swap_file->f_mapping;
360 return mapping->a_ops->set_page_dirty(page);
361 } else {
362 return __set_page_dirty_no_writeback(page);
363 }
364}
365