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23#include <linux/kernel.h>
24#include <linux/module.h>
25#include <linux/types.h>
26#include <linux/fs.h>
27#include <linux/mm.h>
28#include <linux/slab.h>
29#include <linux/highmem.h>
30#include <linux/pagemap.h>
31#include <linux/task_io_accounting_ops.h>
32#include <linux/bio.h>
33#include <linux/wait.h>
34#include <linux/err.h>
35#include <linux/blkdev.h>
36#include <linux/buffer_head.h>
37#include <linux/rwsem.h>
38#include <linux/uio.h>
39#include <linux/atomic.h>
40#include <linux/prefetch.h>
41
42
43
44
45
46#define DIO_PAGES 64
47
48
49
50
51#define DIO_COMPLETE_ASYNC 0x01
52#define DIO_COMPLETE_INVALIDATE 0x02
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68struct dio_submit {
69 struct bio *bio;
70 unsigned blkbits;
71 unsigned blkfactor;
72
73
74
75
76 unsigned start_zero_done;
77
78
79 int pages_in_io;
80 sector_t block_in_file;
81
82 unsigned blocks_available;
83 int reap_counter;
84 sector_t final_block_in_request;
85 int boundary;
86 get_block_t *get_block;
87 dio_submit_t *submit_io;
88
89 loff_t logical_offset_in_bio;
90 sector_t final_block_in_bio;
91 sector_t next_block_for_io;
92
93
94
95
96
97
98
99 struct page *cur_page;
100 unsigned cur_page_offset;
101 unsigned cur_page_len;
102 sector_t cur_page_block;
103 loff_t cur_page_fs_offset;
104
105 struct iov_iter *iter;
106
107
108
109
110 unsigned head;
111 unsigned tail;
112 size_t from, to;
113};
114
115
116struct dio {
117 int flags;
118 int op;
119 int op_flags;
120 blk_qc_t bio_cookie;
121 struct gendisk *bio_disk;
122 struct inode *inode;
123 loff_t i_size;
124 dio_iodone_t *end_io;
125
126 void *private;
127
128
129 spinlock_t bio_lock;
130 int page_errors;
131 int is_async;
132 bool defer_completion;
133 bool should_dirty;
134 int io_error;
135 unsigned long refcount;
136 struct bio *bio_list;
137 struct task_struct *waiter;
138
139
140 struct kiocb *iocb;
141 ssize_t result;
142
143
144
145
146
147
148 union {
149 struct page *pages[DIO_PAGES];
150 struct work_struct complete_work;
151 };
152} ____cacheline_aligned_in_smp;
153
154static struct kmem_cache *dio_cache __read_mostly;
155
156
157
158
159static inline unsigned dio_pages_present(struct dio_submit *sdio)
160{
161 return sdio->tail - sdio->head;
162}
163
164
165
166
167static inline int dio_refill_pages(struct dio *dio, struct dio_submit *sdio)
168{
169 ssize_t ret;
170
171 ret = iov_iter_get_pages(sdio->iter, dio->pages, LONG_MAX, DIO_PAGES,
172 &sdio->from);
173
174 if (ret < 0 && sdio->blocks_available && (dio->op == REQ_OP_WRITE)) {
175 struct page *page = ZERO_PAGE(0);
176
177
178
179
180
181 if (dio->page_errors == 0)
182 dio->page_errors = ret;
183 get_page(page);
184 dio->pages[0] = page;
185 sdio->head = 0;
186 sdio->tail = 1;
187 sdio->from = 0;
188 sdio->to = PAGE_SIZE;
189 return 0;
190 }
191
192 if (ret >= 0) {
193 iov_iter_advance(sdio->iter, ret);
194 ret += sdio->from;
195 sdio->head = 0;
196 sdio->tail = (ret + PAGE_SIZE - 1) / PAGE_SIZE;
197 sdio->to = ((ret - 1) & (PAGE_SIZE - 1)) + 1;
198 return 0;
199 }
200 return ret;
201}
202
203
204
205
206
207
208
209static inline struct page *dio_get_page(struct dio *dio,
210 struct dio_submit *sdio)
211{
212 if (dio_pages_present(sdio) == 0) {
213 int ret;
214
215 ret = dio_refill_pages(dio, sdio);
216 if (ret)
217 return ERR_PTR(ret);
218 BUG_ON(dio_pages_present(sdio) == 0);
219 }
220 return dio->pages[sdio->head];
221}
222
223
224
225
226void dio_warn_stale_pagecache(struct file *filp)
227{
228 static DEFINE_RATELIMIT_STATE(_rs, 86400 * HZ, DEFAULT_RATELIMIT_BURST);
229 char pathname[128];
230 struct inode *inode = file_inode(filp);
231 char *path;
232
233 errseq_set(&inode->i_mapping->wb_err, -EIO);
234 if (__ratelimit(&_rs)) {
235 path = file_path(filp, pathname, sizeof(pathname));
236 if (IS_ERR(path))
237 path = "(unknown)";
238 pr_crit("Page cache invalidation failure on direct I/O. Possible data corruption due to collision with buffered I/O!\n");
239 pr_crit("File: %s PID: %d Comm: %.20s\n", path, current->pid,
240 current->comm);
241 }
242}
243
244
245
246
247
248
249
250
251
252
253
254
255
256static ssize_t dio_complete(struct dio *dio, ssize_t ret, unsigned int flags)
257{
258 loff_t offset = dio->iocb->ki_pos;
259 ssize_t transferred = 0;
260 int err;
261
262
263
264
265
266
267
268 if (ret == -EIOCBQUEUED)
269 ret = 0;
270
271 if (dio->result) {
272 transferred = dio->result;
273
274
275 if ((dio->op == REQ_OP_READ) &&
276 ((offset + transferred) > dio->i_size))
277 transferred = dio->i_size - offset;
278
279 if (unlikely(ret == -EFAULT) && transferred)
280 ret = 0;
281 }
282
283 if (ret == 0)
284 ret = dio->page_errors;
285 if (ret == 0)
286 ret = dio->io_error;
287 if (ret == 0)
288 ret = transferred;
289
290 if (dio->end_io) {
291
292 err = dio->end_io(dio->iocb, offset, ret, dio->private);
293 if (err)
294 ret = err;
295 }
296
297
298
299
300
301
302
303
304
305
306
307
308
309 if (flags & DIO_COMPLETE_INVALIDATE &&
310 ret > 0 && dio->op == REQ_OP_WRITE &&
311 dio->inode->i_mapping->nrpages) {
312 err = invalidate_inode_pages2_range(dio->inode->i_mapping,
313 offset >> PAGE_SHIFT,
314 (offset + ret - 1) >> PAGE_SHIFT);
315 if (err)
316 dio_warn_stale_pagecache(dio->iocb->ki_filp);
317 }
318
319 inode_dio_end(dio->inode);
320
321 if (flags & DIO_COMPLETE_ASYNC) {
322
323
324
325
326
327 dio->iocb->ki_pos += transferred;
328
329 if (ret > 0 && dio->op == REQ_OP_WRITE)
330 ret = generic_write_sync(dio->iocb, ret);
331 dio->iocb->ki_complete(dio->iocb, ret, 0);
332 }
333
334 kmem_cache_free(dio_cache, dio);
335 return ret;
336}
337
338static void dio_aio_complete_work(struct work_struct *work)
339{
340 struct dio *dio = container_of(work, struct dio, complete_work);
341
342 dio_complete(dio, 0, DIO_COMPLETE_ASYNC | DIO_COMPLETE_INVALIDATE);
343}
344
345static blk_status_t dio_bio_complete(struct dio *dio, struct bio *bio);
346
347
348
349
350static void dio_bio_end_aio(struct bio *bio)
351{
352 struct dio *dio = bio->bi_private;
353 unsigned long remaining;
354 unsigned long flags;
355 bool defer_completion = false;
356
357
358 dio_bio_complete(dio, bio);
359
360 spin_lock_irqsave(&dio->bio_lock, flags);
361 remaining = --dio->refcount;
362 if (remaining == 1 && dio->waiter)
363 wake_up_process(dio->waiter);
364 spin_unlock_irqrestore(&dio->bio_lock, flags);
365
366 if (remaining == 0) {
367
368
369
370
371
372
373
374
375 if (dio->result)
376 defer_completion = dio->defer_completion ||
377 (dio->op == REQ_OP_WRITE &&
378 dio->inode->i_mapping->nrpages);
379 if (defer_completion) {
380 INIT_WORK(&dio->complete_work, dio_aio_complete_work);
381 queue_work(dio->inode->i_sb->s_dio_done_wq,
382 &dio->complete_work);
383 } else {
384 dio_complete(dio, 0, DIO_COMPLETE_ASYNC);
385 }
386 }
387}
388
389
390
391
392
393
394
395
396static void dio_bio_end_io(struct bio *bio)
397{
398 struct dio *dio = bio->bi_private;
399 unsigned long flags;
400
401 spin_lock_irqsave(&dio->bio_lock, flags);
402 bio->bi_private = dio->bio_list;
403 dio->bio_list = bio;
404 if (--dio->refcount == 1 && dio->waiter)
405 wake_up_process(dio->waiter);
406 spin_unlock_irqrestore(&dio->bio_lock, flags);
407}
408
409
410
411
412
413
414
415
416
417void dio_end_io(struct bio *bio)
418{
419 struct dio *dio = bio->bi_private;
420
421 if (dio->is_async)
422 dio_bio_end_aio(bio);
423 else
424 dio_bio_end_io(bio);
425}
426EXPORT_SYMBOL_GPL(dio_end_io);
427
428static inline void
429dio_bio_alloc(struct dio *dio, struct dio_submit *sdio,
430 struct block_device *bdev,
431 sector_t first_sector, int nr_vecs)
432{
433 struct bio *bio;
434
435
436
437
438
439 bio = bio_alloc(GFP_KERNEL, nr_vecs);
440
441 bio_set_dev(bio, bdev);
442 bio->bi_iter.bi_sector = first_sector;
443 bio_set_op_attrs(bio, dio->op, dio->op_flags);
444 if (dio->is_async)
445 bio->bi_end_io = dio_bio_end_aio;
446 else
447 bio->bi_end_io = dio_bio_end_io;
448
449 bio->bi_write_hint = dio->iocb->ki_hint;
450
451 sdio->bio = bio;
452 sdio->logical_offset_in_bio = sdio->cur_page_fs_offset;
453}
454
455
456
457
458
459
460
461
462static inline void dio_bio_submit(struct dio *dio, struct dio_submit *sdio)
463{
464 struct bio *bio = sdio->bio;
465 unsigned long flags;
466
467 bio->bi_private = dio;
468
469 spin_lock_irqsave(&dio->bio_lock, flags);
470 dio->refcount++;
471 spin_unlock_irqrestore(&dio->bio_lock, flags);
472
473 if (dio->is_async && dio->op == REQ_OP_READ && dio->should_dirty)
474 bio_set_pages_dirty(bio);
475
476 dio->bio_disk = bio->bi_disk;
477
478 if (sdio->submit_io) {
479 sdio->submit_io(bio, dio->inode, sdio->logical_offset_in_bio);
480 dio->bio_cookie = BLK_QC_T_NONE;
481 } else
482 dio->bio_cookie = submit_bio(bio);
483
484 sdio->bio = NULL;
485 sdio->boundary = 0;
486 sdio->logical_offset_in_bio = 0;
487}
488
489
490
491
492static inline void dio_cleanup(struct dio *dio, struct dio_submit *sdio)
493{
494 while (sdio->head < sdio->tail)
495 put_page(dio->pages[sdio->head++]);
496}
497
498
499
500
501
502
503
504static struct bio *dio_await_one(struct dio *dio)
505{
506 unsigned long flags;
507 struct bio *bio = NULL;
508
509 spin_lock_irqsave(&dio->bio_lock, flags);
510
511
512
513
514
515
516
517 while (dio->refcount > 1 && dio->bio_list == NULL) {
518 __set_current_state(TASK_UNINTERRUPTIBLE);
519 dio->waiter = current;
520 spin_unlock_irqrestore(&dio->bio_lock, flags);
521 if (!(dio->iocb->ki_flags & IOCB_HIPRI) ||
522 !blk_poll(dio->bio_disk->queue, dio->bio_cookie, true))
523 io_schedule();
524
525 spin_lock_irqsave(&dio->bio_lock, flags);
526 dio->waiter = NULL;
527 }
528 if (dio->bio_list) {
529 bio = dio->bio_list;
530 dio->bio_list = bio->bi_private;
531 }
532 spin_unlock_irqrestore(&dio->bio_lock, flags);
533 return bio;
534}
535
536
537
538
539static blk_status_t dio_bio_complete(struct dio *dio, struct bio *bio)
540{
541 struct bio_vec *bvec;
542 blk_status_t err = bio->bi_status;
543
544 if (err) {
545 if (err == BLK_STS_AGAIN && (bio->bi_opf & REQ_NOWAIT))
546 dio->io_error = -EAGAIN;
547 else
548 dio->io_error = -EIO;
549 }
550
551 if (dio->is_async && dio->op == REQ_OP_READ && dio->should_dirty) {
552 bio_check_pages_dirty(bio);
553 } else {
554 struct bvec_iter_all iter_all;
555
556 bio_for_each_segment_all(bvec, bio, iter_all) {
557 struct page *page = bvec->bv_page;
558
559 if (dio->op == REQ_OP_READ && !PageCompound(page) &&
560 dio->should_dirty)
561 set_page_dirty_lock(page);
562 put_page(page);
563 }
564 bio_put(bio);
565 }
566 return err;
567}
568
569
570
571
572
573
574
575
576static void dio_await_completion(struct dio *dio)
577{
578 struct bio *bio;
579 do {
580 bio = dio_await_one(dio);
581 if (bio)
582 dio_bio_complete(dio, bio);
583 } while (bio);
584}
585
586
587
588
589
590
591
592
593static inline int dio_bio_reap(struct dio *dio, struct dio_submit *sdio)
594{
595 int ret = 0;
596
597 if (sdio->reap_counter++ >= 64) {
598 while (dio->bio_list) {
599 unsigned long flags;
600 struct bio *bio;
601 int ret2;
602
603 spin_lock_irqsave(&dio->bio_lock, flags);
604 bio = dio->bio_list;
605 dio->bio_list = bio->bi_private;
606 spin_unlock_irqrestore(&dio->bio_lock, flags);
607 ret2 = blk_status_to_errno(dio_bio_complete(dio, bio));
608 if (ret == 0)
609 ret = ret2;
610 }
611 sdio->reap_counter = 0;
612 }
613 return ret;
614}
615
616
617
618
619
620
621
622int sb_init_dio_done_wq(struct super_block *sb)
623{
624 struct workqueue_struct *old;
625 struct workqueue_struct *wq = alloc_workqueue("dio/%s",
626 WQ_MEM_RECLAIM, 0,
627 sb->s_id);
628 if (!wq)
629 return -ENOMEM;
630
631
632
633 old = cmpxchg(&sb->s_dio_done_wq, NULL, wq);
634
635 if (old)
636 destroy_workqueue(wq);
637 return 0;
638}
639
640static int dio_set_defer_completion(struct dio *dio)
641{
642 struct super_block *sb = dio->inode->i_sb;
643
644 if (dio->defer_completion)
645 return 0;
646 dio->defer_completion = true;
647 if (!sb->s_dio_done_wq)
648 return sb_init_dio_done_wq(sb);
649 return 0;
650}
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675static int get_more_blocks(struct dio *dio, struct dio_submit *sdio,
676 struct buffer_head *map_bh)
677{
678 int ret;
679 sector_t fs_startblk;
680 sector_t fs_endblk;
681 unsigned long fs_count;
682 int create;
683 unsigned int i_blkbits = sdio->blkbits + sdio->blkfactor;
684 loff_t i_size;
685
686
687
688
689
690 ret = dio->page_errors;
691 if (ret == 0) {
692 BUG_ON(sdio->block_in_file >= sdio->final_block_in_request);
693 fs_startblk = sdio->block_in_file >> sdio->blkfactor;
694 fs_endblk = (sdio->final_block_in_request - 1) >>
695 sdio->blkfactor;
696 fs_count = fs_endblk - fs_startblk + 1;
697
698 map_bh->b_state = 0;
699 map_bh->b_size = fs_count << i_blkbits;
700
701
702
703
704
705
706
707
708
709
710
711
712 create = dio->op == REQ_OP_WRITE;
713 if (dio->flags & DIO_SKIP_HOLES) {
714 i_size = i_size_read(dio->inode);
715 if (i_size && fs_startblk <= (i_size - 1) >> i_blkbits)
716 create = 0;
717 }
718
719 ret = (*sdio->get_block)(dio->inode, fs_startblk,
720 map_bh, create);
721
722
723 dio->private = map_bh->b_private;
724
725 if (ret == 0 && buffer_defer_completion(map_bh))
726 ret = dio_set_defer_completion(dio);
727 }
728 return ret;
729}
730
731
732
733
734static inline int dio_new_bio(struct dio *dio, struct dio_submit *sdio,
735 sector_t start_sector, struct buffer_head *map_bh)
736{
737 sector_t sector;
738 int ret, nr_pages;
739
740 ret = dio_bio_reap(dio, sdio);
741 if (ret)
742 goto out;
743 sector = start_sector << (sdio->blkbits - 9);
744 nr_pages = min(sdio->pages_in_io, BIO_MAX_PAGES);
745 BUG_ON(nr_pages <= 0);
746 dio_bio_alloc(dio, sdio, map_bh->b_bdev, sector, nr_pages);
747 sdio->boundary = 0;
748out:
749 return ret;
750}
751
752
753
754
755
756
757
758
759static inline int dio_bio_add_page(struct dio_submit *sdio)
760{
761 int ret;
762
763 ret = bio_add_page(sdio->bio, sdio->cur_page,
764 sdio->cur_page_len, sdio->cur_page_offset);
765 if (ret == sdio->cur_page_len) {
766
767
768
769 if ((sdio->cur_page_len + sdio->cur_page_offset) == PAGE_SIZE)
770 sdio->pages_in_io--;
771 get_page(sdio->cur_page);
772 sdio->final_block_in_bio = sdio->cur_page_block +
773 (sdio->cur_page_len >> sdio->blkbits);
774 ret = 0;
775 } else {
776 ret = 1;
777 }
778 return ret;
779}
780
781
782
783
784
785
786
787
788
789
790
791static inline int dio_send_cur_page(struct dio *dio, struct dio_submit *sdio,
792 struct buffer_head *map_bh)
793{
794 int ret = 0;
795
796 if (sdio->bio) {
797 loff_t cur_offset = sdio->cur_page_fs_offset;
798 loff_t bio_next_offset = sdio->logical_offset_in_bio +
799 sdio->bio->bi_iter.bi_size;
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815 if (sdio->final_block_in_bio != sdio->cur_page_block ||
816 cur_offset != bio_next_offset)
817 dio_bio_submit(dio, sdio);
818 }
819
820 if (sdio->bio == NULL) {
821 ret = dio_new_bio(dio, sdio, sdio->cur_page_block, map_bh);
822 if (ret)
823 goto out;
824 }
825
826 if (dio_bio_add_page(sdio) != 0) {
827 dio_bio_submit(dio, sdio);
828 ret = dio_new_bio(dio, sdio, sdio->cur_page_block, map_bh);
829 if (ret == 0) {
830 ret = dio_bio_add_page(sdio);
831 BUG_ON(ret != 0);
832 }
833 }
834out:
835 return ret;
836}
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855static inline int
856submit_page_section(struct dio *dio, struct dio_submit *sdio, struct page *page,
857 unsigned offset, unsigned len, sector_t blocknr,
858 struct buffer_head *map_bh)
859{
860 int ret = 0;
861
862 if (dio->op == REQ_OP_WRITE) {
863
864
865
866 task_io_account_write(len);
867 }
868
869
870
871
872 if (sdio->cur_page == page &&
873 sdio->cur_page_offset + sdio->cur_page_len == offset &&
874 sdio->cur_page_block +
875 (sdio->cur_page_len >> sdio->blkbits) == blocknr) {
876 sdio->cur_page_len += len;
877 goto out;
878 }
879
880
881
882
883 if (sdio->cur_page) {
884 ret = dio_send_cur_page(dio, sdio, map_bh);
885 put_page(sdio->cur_page);
886 sdio->cur_page = NULL;
887 if (ret)
888 return ret;
889 }
890
891 get_page(page);
892 sdio->cur_page = page;
893 sdio->cur_page_offset = offset;
894 sdio->cur_page_len = len;
895 sdio->cur_page_block = blocknr;
896 sdio->cur_page_fs_offset = sdio->block_in_file << sdio->blkbits;
897out:
898
899
900
901
902 if (sdio->boundary) {
903 ret = dio_send_cur_page(dio, sdio, map_bh);
904 if (sdio->bio)
905 dio_bio_submit(dio, sdio);
906 put_page(sdio->cur_page);
907 sdio->cur_page = NULL;
908 }
909 return ret;
910}
911
912
913
914
915
916
917
918
919
920
921static inline void dio_zero_block(struct dio *dio, struct dio_submit *sdio,
922 int end, struct buffer_head *map_bh)
923{
924 unsigned dio_blocks_per_fs_block;
925 unsigned this_chunk_blocks;
926 unsigned this_chunk_bytes;
927 struct page *page;
928
929 sdio->start_zero_done = 1;
930 if (!sdio->blkfactor || !buffer_new(map_bh))
931 return;
932
933 dio_blocks_per_fs_block = 1 << sdio->blkfactor;
934 this_chunk_blocks = sdio->block_in_file & (dio_blocks_per_fs_block - 1);
935
936 if (!this_chunk_blocks)
937 return;
938
939
940
941
942
943 if (end)
944 this_chunk_blocks = dio_blocks_per_fs_block - this_chunk_blocks;
945
946 this_chunk_bytes = this_chunk_blocks << sdio->blkbits;
947
948 page = ZERO_PAGE(0);
949 if (submit_page_section(dio, sdio, page, 0, this_chunk_bytes,
950 sdio->next_block_for_io, map_bh))
951 return;
952
953 sdio->next_block_for_io += this_chunk_blocks;
954}
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972static int do_direct_IO(struct dio *dio, struct dio_submit *sdio,
973 struct buffer_head *map_bh)
974{
975 const unsigned blkbits = sdio->blkbits;
976 const unsigned i_blkbits = blkbits + sdio->blkfactor;
977 int ret = 0;
978
979 while (sdio->block_in_file < sdio->final_block_in_request) {
980 struct page *page;
981 size_t from, to;
982
983 page = dio_get_page(dio, sdio);
984 if (IS_ERR(page)) {
985 ret = PTR_ERR(page);
986 goto out;
987 }
988 from = sdio->head ? 0 : sdio->from;
989 to = (sdio->head == sdio->tail - 1) ? sdio->to : PAGE_SIZE;
990 sdio->head++;
991
992 while (from < to) {
993 unsigned this_chunk_bytes;
994 unsigned this_chunk_blocks;
995 unsigned u;
996
997 if (sdio->blocks_available == 0) {
998
999
1000
1001 unsigned long blkmask;
1002 unsigned long dio_remainder;
1003
1004 ret = get_more_blocks(dio, sdio, map_bh);
1005 if (ret) {
1006 put_page(page);
1007 goto out;
1008 }
1009 if (!buffer_mapped(map_bh))
1010 goto do_holes;
1011
1012 sdio->blocks_available =
1013 map_bh->b_size >> blkbits;
1014 sdio->next_block_for_io =
1015 map_bh->b_blocknr << sdio->blkfactor;
1016 if (buffer_new(map_bh)) {
1017 clean_bdev_aliases(
1018 map_bh->b_bdev,
1019 map_bh->b_blocknr,
1020 map_bh->b_size >> i_blkbits);
1021 }
1022
1023 if (!sdio->blkfactor)
1024 goto do_holes;
1025
1026 blkmask = (1 << sdio->blkfactor) - 1;
1027 dio_remainder = (sdio->block_in_file & blkmask);
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040 if (!buffer_new(map_bh))
1041 sdio->next_block_for_io += dio_remainder;
1042 sdio->blocks_available -= dio_remainder;
1043 }
1044do_holes:
1045
1046 if (!buffer_mapped(map_bh)) {
1047 loff_t i_size_aligned;
1048
1049
1050 if (dio->op == REQ_OP_WRITE) {
1051 put_page(page);
1052 return -ENOTBLK;
1053 }
1054
1055
1056
1057
1058
1059 i_size_aligned = ALIGN(i_size_read(dio->inode),
1060 1 << blkbits);
1061 if (sdio->block_in_file >=
1062 i_size_aligned >> blkbits) {
1063
1064 put_page(page);
1065 goto out;
1066 }
1067 zero_user(page, from, 1 << blkbits);
1068 sdio->block_in_file++;
1069 from += 1 << blkbits;
1070 dio->result += 1 << blkbits;
1071 goto next_block;
1072 }
1073
1074
1075
1076
1077
1078
1079 if (unlikely(sdio->blkfactor && !sdio->start_zero_done))
1080 dio_zero_block(dio, sdio, 0, map_bh);
1081
1082
1083
1084
1085
1086 this_chunk_blocks = sdio->blocks_available;
1087 u = (to - from) >> blkbits;
1088 if (this_chunk_blocks > u)
1089 this_chunk_blocks = u;
1090 u = sdio->final_block_in_request - sdio->block_in_file;
1091 if (this_chunk_blocks > u)
1092 this_chunk_blocks = u;
1093 this_chunk_bytes = this_chunk_blocks << blkbits;
1094 BUG_ON(this_chunk_bytes == 0);
1095
1096 if (this_chunk_blocks == sdio->blocks_available)
1097 sdio->boundary = buffer_boundary(map_bh);
1098 ret = submit_page_section(dio, sdio, page,
1099 from,
1100 this_chunk_bytes,
1101 sdio->next_block_for_io,
1102 map_bh);
1103 if (ret) {
1104 put_page(page);
1105 goto out;
1106 }
1107 sdio->next_block_for_io += this_chunk_blocks;
1108
1109 sdio->block_in_file += this_chunk_blocks;
1110 from += this_chunk_bytes;
1111 dio->result += this_chunk_bytes;
1112 sdio->blocks_available -= this_chunk_blocks;
1113next_block:
1114 BUG_ON(sdio->block_in_file > sdio->final_block_in_request);
1115 if (sdio->block_in_file == sdio->final_block_in_request)
1116 break;
1117 }
1118
1119
1120 put_page(page);
1121 }
1122out:
1123 return ret;
1124}
1125
1126static inline int drop_refcount(struct dio *dio)
1127{
1128 int ret2;
1129 unsigned long flags;
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142 spin_lock_irqsave(&dio->bio_lock, flags);
1143 ret2 = --dio->refcount;
1144 spin_unlock_irqrestore(&dio->bio_lock, flags);
1145 return ret2;
1146}
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173static inline ssize_t
1174do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
1175 struct block_device *bdev, struct iov_iter *iter,
1176 get_block_t get_block, dio_iodone_t end_io,
1177 dio_submit_t submit_io, int flags)
1178{
1179 unsigned i_blkbits = READ_ONCE(inode->i_blkbits);
1180 unsigned blkbits = i_blkbits;
1181 unsigned blocksize_mask = (1 << blkbits) - 1;
1182 ssize_t retval = -EINVAL;
1183 const size_t count = iov_iter_count(iter);
1184 loff_t offset = iocb->ki_pos;
1185 const loff_t end = offset + count;
1186 struct dio *dio;
1187 struct dio_submit sdio = { 0, };
1188 struct buffer_head map_bh = { 0, };
1189 struct blk_plug plug;
1190 unsigned long align = offset | iov_iter_alignment(iter);
1191
1192
1193
1194
1195
1196
1197 if (align & blocksize_mask) {
1198 if (bdev)
1199 blkbits = blksize_bits(bdev_logical_block_size(bdev));
1200 blocksize_mask = (1 << blkbits) - 1;
1201 if (align & blocksize_mask)
1202 goto out;
1203 }
1204
1205
1206 if (iov_iter_rw(iter) == READ && !count)
1207 return 0;
1208
1209 dio = kmem_cache_alloc(dio_cache, GFP_KERNEL);
1210 retval = -ENOMEM;
1211 if (!dio)
1212 goto out;
1213
1214
1215
1216
1217
1218 memset(dio, 0, offsetof(struct dio, pages));
1219
1220 dio->flags = flags;
1221 if (dio->flags & DIO_LOCKING) {
1222 if (iov_iter_rw(iter) == READ) {
1223 struct address_space *mapping =
1224 iocb->ki_filp->f_mapping;
1225
1226
1227 inode_lock(inode);
1228
1229 retval = filemap_write_and_wait_range(mapping, offset,
1230 end - 1);
1231 if (retval) {
1232 inode_unlock(inode);
1233 kmem_cache_free(dio_cache, dio);
1234 goto out;
1235 }
1236 }
1237 }
1238
1239
1240 dio->i_size = i_size_read(inode);
1241 if (iov_iter_rw(iter) == READ && offset >= dio->i_size) {
1242 if (dio->flags & DIO_LOCKING)
1243 inode_unlock(inode);
1244 kmem_cache_free(dio_cache, dio);
1245 retval = 0;
1246 goto out;
1247 }
1248
1249
1250
1251
1252
1253
1254
1255 if (is_sync_kiocb(iocb))
1256 dio->is_async = false;
1257 else if (iov_iter_rw(iter) == WRITE && end > i_size_read(inode))
1258 dio->is_async = false;
1259 else
1260 dio->is_async = true;
1261
1262 dio->inode = inode;
1263 if (iov_iter_rw(iter) == WRITE) {
1264 dio->op = REQ_OP_WRITE;
1265 dio->op_flags = REQ_SYNC | REQ_IDLE;
1266 if (iocb->ki_flags & IOCB_NOWAIT)
1267 dio->op_flags |= REQ_NOWAIT;
1268 } else {
1269 dio->op = REQ_OP_READ;
1270 }
1271 if (iocb->ki_flags & IOCB_HIPRI)
1272 dio->op_flags |= REQ_HIPRI;
1273
1274
1275
1276
1277
1278 if (dio->is_async && iov_iter_rw(iter) == WRITE) {
1279 retval = 0;
1280 if (iocb->ki_flags & IOCB_DSYNC)
1281 retval = dio_set_defer_completion(dio);
1282 else if (!dio->inode->i_sb->s_dio_done_wq) {
1283
1284
1285
1286
1287
1288 retval = sb_init_dio_done_wq(dio->inode->i_sb);
1289 }
1290 if (retval) {
1291
1292
1293
1294
1295 kmem_cache_free(dio_cache, dio);
1296 goto out;
1297 }
1298 }
1299
1300
1301
1302
1303 inode_dio_begin(inode);
1304
1305 retval = 0;
1306 sdio.blkbits = blkbits;
1307 sdio.blkfactor = i_blkbits - blkbits;
1308 sdio.block_in_file = offset >> blkbits;
1309
1310 sdio.get_block = get_block;
1311 dio->end_io = end_io;
1312 sdio.submit_io = submit_io;
1313 sdio.final_block_in_bio = -1;
1314 sdio.next_block_for_io = -1;
1315
1316 dio->iocb = iocb;
1317
1318 spin_lock_init(&dio->bio_lock);
1319 dio->refcount = 1;
1320
1321 dio->should_dirty = iter_is_iovec(iter) && iov_iter_rw(iter) == READ;
1322 sdio.iter = iter;
1323 sdio.final_block_in_request = end >> blkbits;
1324
1325
1326
1327
1328
1329 if (unlikely(sdio.blkfactor))
1330 sdio.pages_in_io = 2;
1331
1332 sdio.pages_in_io += iov_iter_npages(iter, INT_MAX);
1333
1334 blk_start_plug(&plug);
1335
1336 retval = do_direct_IO(dio, &sdio, &map_bh);
1337 if (retval)
1338 dio_cleanup(dio, &sdio);
1339
1340 if (retval == -ENOTBLK) {
1341
1342
1343
1344
1345 retval = 0;
1346 }
1347
1348
1349
1350
1351 dio_zero_block(dio, &sdio, 1, &map_bh);
1352
1353 if (sdio.cur_page) {
1354 ssize_t ret2;
1355
1356 ret2 = dio_send_cur_page(dio, &sdio, &map_bh);
1357 if (retval == 0)
1358 retval = ret2;
1359 put_page(sdio.cur_page);
1360 sdio.cur_page = NULL;
1361 }
1362 if (sdio.bio)
1363 dio_bio_submit(dio, &sdio);
1364
1365 blk_finish_plug(&plug);
1366
1367
1368
1369
1370
1371 dio_cleanup(dio, &sdio);
1372
1373
1374
1375
1376
1377
1378 if (iov_iter_rw(iter) == READ && (dio->flags & DIO_LOCKING))
1379 inode_unlock(dio->inode);
1380
1381
1382
1383
1384
1385
1386
1387
1388 BUG_ON(retval == -EIOCBQUEUED);
1389 if (dio->is_async && retval == 0 && dio->result &&
1390 (iov_iter_rw(iter) == READ || dio->result == count))
1391 retval = -EIOCBQUEUED;
1392 else
1393 dio_await_completion(dio);
1394
1395 if (drop_refcount(dio) == 0) {
1396 retval = dio_complete(dio, retval, DIO_COMPLETE_INVALIDATE);
1397 } else
1398 BUG_ON(retval != -EIOCBQUEUED);
1399
1400out:
1401 return retval;
1402}
1403
1404ssize_t __blockdev_direct_IO(struct kiocb *iocb, struct inode *inode,
1405 struct block_device *bdev, struct iov_iter *iter,
1406 get_block_t get_block,
1407 dio_iodone_t end_io, dio_submit_t submit_io,
1408 int flags)
1409{
1410
1411
1412
1413
1414
1415
1416
1417
1418 prefetch(&bdev->bd_disk->part_tbl);
1419 prefetch(bdev->bd_queue);
1420 prefetch((char *)bdev->bd_queue + SMP_CACHE_BYTES);
1421
1422 return do_blockdev_direct_IO(iocb, inode, bdev, iter, get_block,
1423 end_io, submit_io, flags);
1424}
1425
1426EXPORT_SYMBOL(__blockdev_direct_IO);
1427
1428static __init int dio_init(void)
1429{
1430 dio_cache = KMEM_CACHE(dio, SLAB_PANIC);
1431 return 0;
1432}
1433module_init(dio_init)
1434