thermal: fix Mediatek thermal controller build
[linux/fpc-iii.git] / mm / page_io.c
blobcd92e3d67a32201fac72196a050fb6e47017d33d
1 /*
2 * linux/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
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/blkdev.h>
24 #include <linux/uio.h>
25 #include <asm/pgtable.h>
27 static struct bio *get_swap_bio(gfp_t gfp_flags,
28 struct page *page, bio_end_io_t end_io)
30 struct bio *bio;
32 bio = bio_alloc(gfp_flags, 1);
33 if (bio) {
34 bio->bi_iter.bi_sector = map_swap_page(page, &bio->bi_bdev);
35 bio->bi_iter.bi_sector <<= PAGE_SHIFT - 9;
36 bio->bi_end_io = end_io;
38 bio_add_page(bio, page, PAGE_SIZE, 0);
39 BUG_ON(bio->bi_iter.bi_size != PAGE_SIZE);
41 return bio;
44 void end_swap_bio_write(struct bio *bio)
46 struct page *page = bio->bi_io_vec[0].bv_page;
48 if (bio->bi_error) {
49 SetPageError(page);
51 * We failed to write the page out to swap-space.
52 * Re-dirty the page in order to avoid it being reclaimed.
53 * Also print a dire warning that things will go BAD (tm)
54 * very quickly.
56 * Also clear PG_reclaim to avoid rotate_reclaimable_page()
58 set_page_dirty(page);
59 pr_alert("Write-error on swap-device (%u:%u:%llu)\n",
60 imajor(bio->bi_bdev->bd_inode),
61 iminor(bio->bi_bdev->bd_inode),
62 (unsigned long long)bio->bi_iter.bi_sector);
63 ClearPageReclaim(page);
65 end_page_writeback(page);
66 bio_put(bio);
69 static void swap_slot_free_notify(struct page *page)
71 struct swap_info_struct *sis;
72 struct gendisk *disk;
75 * There is no guarantee that the page is in swap cache - the software
76 * suspend code (at least) uses end_swap_bio_read() against a non-
77 * swapcache page. So we must check PG_swapcache before proceeding with
78 * this optimization.
80 if (unlikely(!PageSwapCache(page)))
81 return;
83 sis = page_swap_info(page);
84 if (!(sis->flags & SWP_BLKDEV))
85 return;
88 * The swap subsystem performs lazy swap slot freeing,
89 * expecting that the page will be swapped out again.
90 * So we can avoid an unnecessary write if the page
91 * isn't redirtied.
92 * This is good for real swap storage because we can
93 * reduce unnecessary I/O and enhance wear-leveling
94 * if an SSD is used as the as swap device.
95 * But if in-memory swap device (eg zram) is used,
96 * this causes a duplicated copy between uncompressed
97 * data in VM-owned memory and compressed data in
98 * zram-owned memory. So let's free zram-owned memory
99 * and make the VM-owned decompressed page *dirty*,
100 * so the page should be swapped out somewhere again if
101 * we again wish to reclaim it.
103 disk = sis->bdev->bd_disk;
104 if (disk->fops->swap_slot_free_notify) {
105 swp_entry_t entry;
106 unsigned long offset;
108 entry.val = page_private(page);
109 offset = swp_offset(entry);
111 SetPageDirty(page);
112 disk->fops->swap_slot_free_notify(sis->bdev,
113 offset);
117 static void end_swap_bio_read(struct bio *bio)
119 struct page *page = bio->bi_io_vec[0].bv_page;
121 if (bio->bi_error) {
122 SetPageError(page);
123 ClearPageUptodate(page);
124 pr_alert("Read-error on swap-device (%u:%u:%llu)\n",
125 imajor(bio->bi_bdev->bd_inode),
126 iminor(bio->bi_bdev->bd_inode),
127 (unsigned long long)bio->bi_iter.bi_sector);
128 goto out;
131 SetPageUptodate(page);
132 swap_slot_free_notify(page);
133 out:
134 unlock_page(page);
135 bio_put(bio);
138 int generic_swapfile_activate(struct swap_info_struct *sis,
139 struct file *swap_file,
140 sector_t *span)
142 struct address_space *mapping = swap_file->f_mapping;
143 struct inode *inode = mapping->host;
144 unsigned blocks_per_page;
145 unsigned long page_no;
146 unsigned blkbits;
147 sector_t probe_block;
148 sector_t last_block;
149 sector_t lowest_block = -1;
150 sector_t highest_block = 0;
151 int nr_extents = 0;
152 int ret;
154 blkbits = inode->i_blkbits;
155 blocks_per_page = PAGE_SIZE >> blkbits;
158 * Map all the blocks into the extent list. This code doesn't try
159 * to be very smart.
161 probe_block = 0;
162 page_no = 0;
163 last_block = i_size_read(inode) >> blkbits;
164 while ((probe_block + blocks_per_page) <= last_block &&
165 page_no < sis->max) {
166 unsigned block_in_page;
167 sector_t first_block;
169 first_block = bmap(inode, probe_block);
170 if (first_block == 0)
171 goto bad_bmap;
174 * It must be PAGE_SIZE aligned on-disk
176 if (first_block & (blocks_per_page - 1)) {
177 probe_block++;
178 goto reprobe;
181 for (block_in_page = 1; block_in_page < blocks_per_page;
182 block_in_page++) {
183 sector_t block;
185 block = bmap(inode, probe_block + block_in_page);
186 if (block == 0)
187 goto bad_bmap;
188 if (block != first_block + block_in_page) {
189 /* Discontiguity */
190 probe_block++;
191 goto reprobe;
195 first_block >>= (PAGE_SHIFT - blkbits);
196 if (page_no) { /* exclude the header page */
197 if (first_block < lowest_block)
198 lowest_block = first_block;
199 if (first_block > highest_block)
200 highest_block = first_block;
204 * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks
206 ret = add_swap_extent(sis, page_no, 1, first_block);
207 if (ret < 0)
208 goto out;
209 nr_extents += ret;
210 page_no++;
211 probe_block += blocks_per_page;
212 reprobe:
213 continue;
215 ret = nr_extents;
216 *span = 1 + highest_block - lowest_block;
217 if (page_no == 0)
218 page_no = 1; /* force Empty message */
219 sis->max = page_no;
220 sis->pages = page_no - 1;
221 sis->highest_bit = page_no - 1;
222 out:
223 return ret;
224 bad_bmap:
225 pr_err("swapon: swapfile has holes\n");
226 ret = -EINVAL;
227 goto out;
231 * We may have stale swap cache pages in memory: notice
232 * them here and get rid of the unnecessary final write.
234 int swap_writepage(struct page *page, struct writeback_control *wbc)
236 int ret = 0;
238 if (try_to_free_swap(page)) {
239 unlock_page(page);
240 goto out;
242 if (frontswap_store(page) == 0) {
243 set_page_writeback(page);
244 unlock_page(page);
245 end_page_writeback(page);
246 goto out;
248 ret = __swap_writepage(page, wbc, end_swap_bio_write);
249 out:
250 return ret;
253 static sector_t swap_page_sector(struct page *page)
255 return (sector_t)__page_file_index(page) << (PAGE_SHIFT - 9);
258 int __swap_writepage(struct page *page, struct writeback_control *wbc,
259 bio_end_io_t end_write_func)
261 struct bio *bio;
262 int ret, rw = WRITE;
263 struct swap_info_struct *sis = page_swap_info(page);
265 if (sis->flags & SWP_FILE) {
266 struct kiocb kiocb;
267 struct file *swap_file = sis->swap_file;
268 struct address_space *mapping = swap_file->f_mapping;
269 struct bio_vec bv = {
270 .bv_page = page,
271 .bv_len = PAGE_SIZE,
272 .bv_offset = 0
274 struct iov_iter from;
276 iov_iter_bvec(&from, ITER_BVEC | WRITE, &bv, 1, PAGE_SIZE);
277 init_sync_kiocb(&kiocb, swap_file);
278 kiocb.ki_pos = page_file_offset(page);
280 set_page_writeback(page);
281 unlock_page(page);
282 ret = mapping->a_ops->direct_IO(&kiocb, &from, kiocb.ki_pos);
283 if (ret == PAGE_SIZE) {
284 count_vm_event(PSWPOUT);
285 ret = 0;
286 } else {
288 * In the case of swap-over-nfs, this can be a
289 * temporary failure if the system has limited
290 * memory for allocating transmit buffers.
291 * Mark the page dirty and avoid
292 * rotate_reclaimable_page but rate-limit the
293 * messages but do not flag PageError like
294 * the normal direct-to-bio case as it could
295 * be temporary.
297 set_page_dirty(page);
298 ClearPageReclaim(page);
299 pr_err_ratelimited("Write error on dio swapfile (%llu)\n",
300 page_file_offset(page));
302 end_page_writeback(page);
303 return ret;
306 ret = bdev_write_page(sis->bdev, swap_page_sector(page), page, wbc);
307 if (!ret) {
308 count_vm_event(PSWPOUT);
309 return 0;
312 ret = 0;
313 bio = get_swap_bio(GFP_NOIO, page, end_write_func);
314 if (bio == NULL) {
315 set_page_dirty(page);
316 unlock_page(page);
317 ret = -ENOMEM;
318 goto out;
320 if (wbc->sync_mode == WB_SYNC_ALL)
321 rw |= REQ_SYNC;
322 count_vm_event(PSWPOUT);
323 set_page_writeback(page);
324 unlock_page(page);
325 submit_bio(rw, bio);
326 out:
327 return ret;
330 int swap_readpage(struct page *page)
332 struct bio *bio;
333 int ret = 0;
334 struct swap_info_struct *sis = page_swap_info(page);
336 VM_BUG_ON_PAGE(!PageLocked(page), page);
337 VM_BUG_ON_PAGE(PageUptodate(page), page);
338 if (frontswap_load(page) == 0) {
339 SetPageUptodate(page);
340 unlock_page(page);
341 goto out;
344 if (sis->flags & SWP_FILE) {
345 struct file *swap_file = sis->swap_file;
346 struct address_space *mapping = swap_file->f_mapping;
348 ret = mapping->a_ops->readpage(swap_file, page);
349 if (!ret)
350 count_vm_event(PSWPIN);
351 return ret;
354 ret = bdev_read_page(sis->bdev, swap_page_sector(page), page);
355 if (!ret) {
356 swap_slot_free_notify(page);
357 count_vm_event(PSWPIN);
358 return 0;
361 ret = 0;
362 bio = get_swap_bio(GFP_KERNEL, page, end_swap_bio_read);
363 if (bio == NULL) {
364 unlock_page(page);
365 ret = -ENOMEM;
366 goto out;
368 count_vm_event(PSWPIN);
369 submit_bio(READ, bio);
370 out:
371 return ret;
374 int swap_set_page_dirty(struct page *page)
376 struct swap_info_struct *sis = page_swap_info(page);
378 if (sis->flags & SWP_FILE) {
379 struct address_space *mapping = sis->swap_file->f_mapping;
380 return mapping->a_ops->set_page_dirty(page);
381 } else {
382 return __set_page_dirty_no_writeback(page);