arm64: dts: imx8mm: Drop deprecated regulator-compatible from Variscite VAR-SOM-MX8MM
[linux-2.6-microblaze.git] / mm / page_io.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  linux/mm/page_io.c
4  *
5  *  Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
6  *
7  *  Swap reorganised 29.12.95, 
8  *  Asynchronous swapping added 30.12.95. Stephen Tweedie
9  *  Removed race in async swapping. 14.4.1996. Bruno Haible
10  *  Add swap of shared pages through the page cache. 20.2.1998. Stephen Tweedie
11  *  Always use brw_page, life becomes simpler. 12 May 1998 Eric Biederman
12  */
13
14 #include <linux/mm.h>
15 #include <linux/kernel_stat.h>
16 #include <linux/gfp.h>
17 #include <linux/pagemap.h>
18 #include <linux/swap.h>
19 #include <linux/bio.h>
20 #include <linux/swapops.h>
21 #include <linux/buffer_head.h>
22 #include <linux/writeback.h>
23 #include <linux/frontswap.h>
24 #include <linux/blkdev.h>
25 #include <linux/psi.h>
26 #include <linux/uio.h>
27 #include <linux/sched/task.h>
28 #include <linux/delayacct.h>
29 #include "swap.h"
30
31 static void end_swap_bio_write(struct bio *bio)
32 {
33         struct page *page = bio_first_page_all(bio);
34
35         if (bio->bi_status) {
36                 SetPageError(page);
37                 /*
38                  * We failed to write the page out to swap-space.
39                  * Re-dirty the page in order to avoid it being reclaimed.
40                  * Also print a dire warning that things will go BAD (tm)
41                  * very quickly.
42                  *
43                  * Also clear PG_reclaim to avoid folio_rotate_reclaimable()
44                  */
45                 set_page_dirty(page);
46                 pr_alert_ratelimited("Write-error on swap-device (%u:%u:%llu)\n",
47                                      MAJOR(bio_dev(bio)), MINOR(bio_dev(bio)),
48                                      (unsigned long long)bio->bi_iter.bi_sector);
49                 ClearPageReclaim(page);
50         }
51         end_page_writeback(page);
52         bio_put(bio);
53 }
54
55 static void end_swap_bio_read(struct bio *bio)
56 {
57         struct page *page = bio_first_page_all(bio);
58         struct task_struct *waiter = bio->bi_private;
59
60         if (bio->bi_status) {
61                 SetPageError(page);
62                 ClearPageUptodate(page);
63                 pr_alert_ratelimited("Read-error on swap-device (%u:%u:%llu)\n",
64                                      MAJOR(bio_dev(bio)), MINOR(bio_dev(bio)),
65                                      (unsigned long long)bio->bi_iter.bi_sector);
66                 goto out;
67         }
68
69         SetPageUptodate(page);
70 out:
71         unlock_page(page);
72         WRITE_ONCE(bio->bi_private, NULL);
73         bio_put(bio);
74         if (waiter) {
75                 blk_wake_io_task(waiter);
76                 put_task_struct(waiter);
77         }
78 }
79
80 int generic_swapfile_activate(struct swap_info_struct *sis,
81                                 struct file *swap_file,
82                                 sector_t *span)
83 {
84         struct address_space *mapping = swap_file->f_mapping;
85         struct inode *inode = mapping->host;
86         unsigned blocks_per_page;
87         unsigned long page_no;
88         unsigned blkbits;
89         sector_t probe_block;
90         sector_t last_block;
91         sector_t lowest_block = -1;
92         sector_t highest_block = 0;
93         int nr_extents = 0;
94         int ret;
95
96         blkbits = inode->i_blkbits;
97         blocks_per_page = PAGE_SIZE >> blkbits;
98
99         /*
100          * Map all the blocks into the extent tree.  This code doesn't try
101          * to be very smart.
102          */
103         probe_block = 0;
104         page_no = 0;
105         last_block = i_size_read(inode) >> blkbits;
106         while ((probe_block + blocks_per_page) <= last_block &&
107                         page_no < sis->max) {
108                 unsigned block_in_page;
109                 sector_t first_block;
110
111                 cond_resched();
112
113                 first_block = probe_block;
114                 ret = bmap(inode, &first_block);
115                 if (ret || !first_block)
116                         goto bad_bmap;
117
118                 /*
119                  * It must be PAGE_SIZE aligned on-disk
120                  */
121                 if (first_block & (blocks_per_page - 1)) {
122                         probe_block++;
123                         goto reprobe;
124                 }
125
126                 for (block_in_page = 1; block_in_page < blocks_per_page;
127                                         block_in_page++) {
128                         sector_t block;
129
130                         block = probe_block + block_in_page;
131                         ret = bmap(inode, &block);
132                         if (ret || !block)
133                                 goto bad_bmap;
134
135                         if (block != first_block + block_in_page) {
136                                 /* Discontiguity */
137                                 probe_block++;
138                                 goto reprobe;
139                         }
140                 }
141
142                 first_block >>= (PAGE_SHIFT - blkbits);
143                 if (page_no) {  /* exclude the header page */
144                         if (first_block < lowest_block)
145                                 lowest_block = first_block;
146                         if (first_block > highest_block)
147                                 highest_block = first_block;
148                 }
149
150                 /*
151                  * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks
152                  */
153                 ret = add_swap_extent(sis, page_no, 1, first_block);
154                 if (ret < 0)
155                         goto out;
156                 nr_extents += ret;
157                 page_no++;
158                 probe_block += blocks_per_page;
159 reprobe:
160                 continue;
161         }
162         ret = nr_extents;
163         *span = 1 + highest_block - lowest_block;
164         if (page_no == 0)
165                 page_no = 1;    /* force Empty message */
166         sis->max = page_no;
167         sis->pages = page_no - 1;
168         sis->highest_bit = page_no - 1;
169 out:
170         return ret;
171 bad_bmap:
172         pr_err("swapon: swapfile has holes\n");
173         ret = -EINVAL;
174         goto out;
175 }
176
177 /*
178  * We may have stale swap cache pages in memory: notice
179  * them here and get rid of the unnecessary final write.
180  */
181 int swap_writepage(struct page *page, struct writeback_control *wbc)
182 {
183         struct folio *folio = page_folio(page);
184         int ret = 0;
185
186         if (folio_free_swap(folio)) {
187                 folio_unlock(folio);
188                 goto out;
189         }
190         /*
191          * Arch code may have to preserve more data than just the page
192          * contents, e.g. memory tags.
193          */
194         ret = arch_prepare_to_swap(&folio->page);
195         if (ret) {
196                 folio_mark_dirty(folio);
197                 folio_unlock(folio);
198                 goto out;
199         }
200         if (frontswap_store(&folio->page) == 0) {
201                 folio_start_writeback(folio);
202                 folio_unlock(folio);
203                 folio_end_writeback(folio);
204                 goto out;
205         }
206         ret = __swap_writepage(&folio->page, wbc);
207 out:
208         return ret;
209 }
210
211 static inline void count_swpout_vm_event(struct page *page)
212 {
213 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
214         if (unlikely(PageTransHuge(page)))
215                 count_vm_event(THP_SWPOUT);
216 #endif
217         count_vm_events(PSWPOUT, thp_nr_pages(page));
218 }
219
220 #if defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
221 static void bio_associate_blkg_from_page(struct bio *bio, struct page *page)
222 {
223         struct cgroup_subsys_state *css;
224         struct mem_cgroup *memcg;
225
226         memcg = page_memcg(page);
227         if (!memcg)
228                 return;
229
230         rcu_read_lock();
231         css = cgroup_e_css(memcg->css.cgroup, &io_cgrp_subsys);
232         bio_associate_blkg_from_css(bio, css);
233         rcu_read_unlock();
234 }
235 #else
236 #define bio_associate_blkg_from_page(bio, page)         do { } while (0)
237 #endif /* CONFIG_MEMCG && CONFIG_BLK_CGROUP */
238
239 struct swap_iocb {
240         struct kiocb            iocb;
241         struct bio_vec          bvec[SWAP_CLUSTER_MAX];
242         int                     pages;
243         int                     len;
244 };
245 static mempool_t *sio_pool;
246
247 int sio_pool_init(void)
248 {
249         if (!sio_pool) {
250                 mempool_t *pool = mempool_create_kmalloc_pool(
251                         SWAP_CLUSTER_MAX, sizeof(struct swap_iocb));
252                 if (cmpxchg(&sio_pool, NULL, pool))
253                         mempool_destroy(pool);
254         }
255         if (!sio_pool)
256                 return -ENOMEM;
257         return 0;
258 }
259
260 static void sio_write_complete(struct kiocb *iocb, long ret)
261 {
262         struct swap_iocb *sio = container_of(iocb, struct swap_iocb, iocb);
263         struct page *page = sio->bvec[0].bv_page;
264         int p;
265
266         if (ret != sio->len) {
267                 /*
268                  * In the case of swap-over-nfs, this can be a
269                  * temporary failure if the system has limited
270                  * memory for allocating transmit buffers.
271                  * Mark the page dirty and avoid
272                  * folio_rotate_reclaimable but rate-limit the
273                  * messages but do not flag PageError like
274                  * the normal direct-to-bio case as it could
275                  * be temporary.
276                  */
277                 pr_err_ratelimited("Write error %ld on dio swapfile (%llu)\n",
278                                    ret, page_file_offset(page));
279                 for (p = 0; p < sio->pages; p++) {
280                         page = sio->bvec[p].bv_page;
281                         set_page_dirty(page);
282                         ClearPageReclaim(page);
283                 }
284         } else {
285                 for (p = 0; p < sio->pages; p++)
286                         count_swpout_vm_event(sio->bvec[p].bv_page);
287         }
288
289         for (p = 0; p < sio->pages; p++)
290                 end_page_writeback(sio->bvec[p].bv_page);
291
292         mempool_free(sio, sio_pool);
293 }
294
295 static int swap_writepage_fs(struct page *page, struct writeback_control *wbc)
296 {
297         struct swap_iocb *sio = NULL;
298         struct swap_info_struct *sis = page_swap_info(page);
299         struct file *swap_file = sis->swap_file;
300         loff_t pos = page_file_offset(page);
301
302         set_page_writeback(page);
303         unlock_page(page);
304         if (wbc->swap_plug)
305                 sio = *wbc->swap_plug;
306         if (sio) {
307                 if (sio->iocb.ki_filp != swap_file ||
308                     sio->iocb.ki_pos + sio->len != pos) {
309                         swap_write_unplug(sio);
310                         sio = NULL;
311                 }
312         }
313         if (!sio) {
314                 sio = mempool_alloc(sio_pool, GFP_NOIO);
315                 init_sync_kiocb(&sio->iocb, swap_file);
316                 sio->iocb.ki_complete = sio_write_complete;
317                 sio->iocb.ki_pos = pos;
318                 sio->pages = 0;
319                 sio->len = 0;
320         }
321         sio->bvec[sio->pages].bv_page = page;
322         sio->bvec[sio->pages].bv_len = thp_size(page);
323         sio->bvec[sio->pages].bv_offset = 0;
324         sio->len += thp_size(page);
325         sio->pages += 1;
326         if (sio->pages == ARRAY_SIZE(sio->bvec) || !wbc->swap_plug) {
327                 swap_write_unplug(sio);
328                 sio = NULL;
329         }
330         if (wbc->swap_plug)
331                 *wbc->swap_plug = sio;
332
333         return 0;
334 }
335
336 int __swap_writepage(struct page *page, struct writeback_control *wbc)
337 {
338         struct bio *bio;
339         int ret;
340         struct swap_info_struct *sis = page_swap_info(page);
341
342         VM_BUG_ON_PAGE(!PageSwapCache(page), page);
343         /*
344          * ->flags can be updated non-atomicially (scan_swap_map_slots),
345          * but that will never affect SWP_FS_OPS, so the data_race
346          * is safe.
347          */
348         if (data_race(sis->flags & SWP_FS_OPS))
349                 return swap_writepage_fs(page, wbc);
350
351         ret = bdev_write_page(sis->bdev, swap_page_sector(page), page, wbc);
352         if (!ret) {
353                 count_swpout_vm_event(page);
354                 return 0;
355         }
356
357         bio = bio_alloc(sis->bdev, 1,
358                         REQ_OP_WRITE | REQ_SWAP | wbc_to_write_flags(wbc),
359                         GFP_NOIO);
360         bio->bi_iter.bi_sector = swap_page_sector(page);
361         bio->bi_end_io = end_swap_bio_write;
362         bio_add_page(bio, page, thp_size(page), 0);
363
364         bio_associate_blkg_from_page(bio, page);
365         count_swpout_vm_event(page);
366         set_page_writeback(page);
367         unlock_page(page);
368         submit_bio(bio);
369
370         return 0;
371 }
372
373 void swap_write_unplug(struct swap_iocb *sio)
374 {
375         struct iov_iter from;
376         struct address_space *mapping = sio->iocb.ki_filp->f_mapping;
377         int ret;
378
379         iov_iter_bvec(&from, ITER_SOURCE, sio->bvec, sio->pages, sio->len);
380         ret = mapping->a_ops->swap_rw(&sio->iocb, &from);
381         if (ret != -EIOCBQUEUED)
382                 sio_write_complete(&sio->iocb, ret);
383 }
384
385 static void sio_read_complete(struct kiocb *iocb, long ret)
386 {
387         struct swap_iocb *sio = container_of(iocb, struct swap_iocb, iocb);
388         int p;
389
390         if (ret == sio->len) {
391                 for (p = 0; p < sio->pages; p++) {
392                         struct page *page = sio->bvec[p].bv_page;
393
394                         SetPageUptodate(page);
395                         unlock_page(page);
396                 }
397                 count_vm_events(PSWPIN, sio->pages);
398         } else {
399                 for (p = 0; p < sio->pages; p++) {
400                         struct page *page = sio->bvec[p].bv_page;
401
402                         SetPageError(page);
403                         ClearPageUptodate(page);
404                         unlock_page(page);
405                 }
406                 pr_alert_ratelimited("Read-error on swap-device\n");
407         }
408         mempool_free(sio, sio_pool);
409 }
410
411 static void swap_readpage_fs(struct page *page,
412                              struct swap_iocb **plug)
413 {
414         struct swap_info_struct *sis = page_swap_info(page);
415         struct swap_iocb *sio = NULL;
416         loff_t pos = page_file_offset(page);
417
418         if (plug)
419                 sio = *plug;
420         if (sio) {
421                 if (sio->iocb.ki_filp != sis->swap_file ||
422                     sio->iocb.ki_pos + sio->len != pos) {
423                         swap_read_unplug(sio);
424                         sio = NULL;
425                 }
426         }
427         if (!sio) {
428                 sio = mempool_alloc(sio_pool, GFP_KERNEL);
429                 init_sync_kiocb(&sio->iocb, sis->swap_file);
430                 sio->iocb.ki_pos = pos;
431                 sio->iocb.ki_complete = sio_read_complete;
432                 sio->pages = 0;
433                 sio->len = 0;
434         }
435         sio->bvec[sio->pages].bv_page = page;
436         sio->bvec[sio->pages].bv_len = thp_size(page);
437         sio->bvec[sio->pages].bv_offset = 0;
438         sio->len += thp_size(page);
439         sio->pages += 1;
440         if (sio->pages == ARRAY_SIZE(sio->bvec) || !plug) {
441                 swap_read_unplug(sio);
442                 sio = NULL;
443         }
444         if (plug)
445                 *plug = sio;
446 }
447
448 int swap_readpage(struct page *page, bool synchronous,
449                   struct swap_iocb **plug)
450 {
451         struct bio *bio;
452         int ret = 0;
453         struct swap_info_struct *sis = page_swap_info(page);
454         bool workingset = PageWorkingset(page);
455         unsigned long pflags;
456         bool in_thrashing;
457
458         VM_BUG_ON_PAGE(!PageSwapCache(page) && !synchronous, page);
459         VM_BUG_ON_PAGE(!PageLocked(page), page);
460         VM_BUG_ON_PAGE(PageUptodate(page), page);
461
462         /*
463          * Count submission time as memory stall and delay. When the device
464          * is congested, or the submitting cgroup IO-throttled, submission
465          * can be a significant part of overall IO time.
466          */
467         if (workingset) {
468                 delayacct_thrashing_start(&in_thrashing);
469                 psi_memstall_enter(&pflags);
470         }
471         delayacct_swapin_start();
472
473         if (frontswap_load(page) == 0) {
474                 SetPageUptodate(page);
475                 unlock_page(page);
476                 goto out;
477         }
478
479         if (data_race(sis->flags & SWP_FS_OPS)) {
480                 swap_readpage_fs(page, plug);
481                 goto out;
482         }
483
484         if (sis->flags & SWP_SYNCHRONOUS_IO) {
485                 ret = bdev_read_page(sis->bdev, swap_page_sector(page), page);
486                 if (!ret) {
487                         count_vm_event(PSWPIN);
488                         goto out;
489                 }
490         }
491
492         ret = 0;
493         bio = bio_alloc(sis->bdev, 1, REQ_OP_READ, GFP_KERNEL);
494         bio->bi_iter.bi_sector = swap_page_sector(page);
495         bio->bi_end_io = end_swap_bio_read;
496         bio_add_page(bio, page, thp_size(page), 0);
497         /*
498          * Keep this task valid during swap readpage because the oom killer may
499          * attempt to access it in the page fault retry time check.
500          */
501         if (synchronous) {
502                 get_task_struct(current);
503                 bio->bi_private = current;
504         }
505         count_vm_event(PSWPIN);
506         bio_get(bio);
507         submit_bio(bio);
508         while (synchronous) {
509                 set_current_state(TASK_UNINTERRUPTIBLE);
510                 if (!READ_ONCE(bio->bi_private))
511                         break;
512
513                 blk_io_schedule();
514         }
515         __set_current_state(TASK_RUNNING);
516         bio_put(bio);
517
518 out:
519         if (workingset) {
520                 delayacct_thrashing_end(&in_thrashing);
521                 psi_memstall_leave(&pflags);
522         }
523         delayacct_swapin_end();
524         return ret;
525 }
526
527 void __swap_read_unplug(struct swap_iocb *sio)
528 {
529         struct iov_iter from;
530         struct address_space *mapping = sio->iocb.ki_filp->f_mapping;
531         int ret;
532
533         iov_iter_bvec(&from, ITER_DEST, sio->bvec, sio->pages, sio->len);
534         ret = mapping->a_ops->swap_rw(&sio->iocb, &from);
535         if (ret != -EIOCBQUEUED)
536                 sio_read_complete(&sio->iocb, ret);
537 }