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