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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 <asm/atomic.h>
39
40
41
42
43
44#define DIO_PAGES 64
45
46
47
48
49
50
51
52
53
54
55
56
57
58struct dio {
59
60 struct bio *bio;
61 struct inode *inode;
62 int rw;
63 loff_t i_size;
64 int flags;
65 unsigned blkbits;
66 unsigned blkfactor;
67
68
69
70
71 unsigned start_zero_done;
72
73
74 int pages_in_io;
75 size_t size;
76 sector_t block_in_file;
77
78 unsigned blocks_available;
79 sector_t final_block_in_request;
80 unsigned first_block_in_page;
81 int boundary;
82 int reap_counter;
83 get_block_t *get_block;
84 dio_iodone_t *end_io;
85 dio_submit_t *submit_io;
86 loff_t logical_offset_in_bio;
87 sector_t final_block_in_bio;
88 sector_t next_block_for_io;
89
90 struct buffer_head map_bh;
91
92
93
94
95
96
97 struct page *cur_page;
98 unsigned cur_page_offset;
99 unsigned cur_page_len;
100 sector_t cur_page_block;
101 loff_t cur_page_fs_offset;
102
103
104 spinlock_t bio_lock;
105 unsigned long refcount;
106 struct bio *bio_list;
107 struct task_struct *waiter;
108
109
110 struct kiocb *iocb;
111 int is_async;
112 int io_error;
113 ssize_t result;
114
115
116
117
118 int curr_page;
119 int total_pages;
120 unsigned long curr_user_address;
121
122
123
124
125
126 unsigned head;
127 unsigned tail;
128 int page_errors;
129
130
131
132
133
134
135 struct page *pages[DIO_PAGES];
136};
137
138
139
140
141static inline unsigned dio_pages_present(struct dio *dio)
142{
143 return dio->tail - dio->head;
144}
145
146
147
148
149static int dio_refill_pages(struct dio *dio)
150{
151 int ret;
152 int nr_pages;
153
154 nr_pages = min(dio->total_pages - dio->curr_page, DIO_PAGES);
155 ret = get_user_pages_fast(
156 dio->curr_user_address,
157 nr_pages,
158 dio->rw == READ,
159 &dio->pages[0]);
160
161 if (ret < 0 && dio->blocks_available && (dio->rw & WRITE)) {
162 struct page *page = ZERO_PAGE(0);
163
164
165
166
167
168 if (dio->page_errors == 0)
169 dio->page_errors = ret;
170 page_cache_get(page);
171 dio->pages[0] = page;
172 dio->head = 0;
173 dio->tail = 1;
174 ret = 0;
175 goto out;
176 }
177
178 if (ret >= 0) {
179 dio->curr_user_address += ret * PAGE_SIZE;
180 dio->curr_page += ret;
181 dio->head = 0;
182 dio->tail = ret;
183 ret = 0;
184 }
185out:
186 return ret;
187}
188
189
190
191
192
193
194
195static struct page *dio_get_page(struct dio *dio)
196{
197 if (dio_pages_present(dio) == 0) {
198 int ret;
199
200 ret = dio_refill_pages(dio);
201 if (ret)
202 return ERR_PTR(ret);
203 BUG_ON(dio_pages_present(dio) == 0);
204 }
205 return dio->pages[dio->head++];
206}
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221static ssize_t dio_complete(struct dio *dio, loff_t offset, ssize_t ret, bool is_async)
222{
223 ssize_t transferred = 0;
224
225
226
227
228
229
230
231 if (ret == -EIOCBQUEUED)
232 ret = 0;
233
234 if (dio->result) {
235 transferred = dio->result;
236
237
238 if ((dio->rw == READ) && ((offset + transferred) > dio->i_size))
239 transferred = dio->i_size - offset;
240 }
241
242 if (ret == 0)
243 ret = dio->page_errors;
244 if (ret == 0)
245 ret = dio->io_error;
246 if (ret == 0)
247 ret = transferred;
248
249 if (dio->end_io && dio->result) {
250 dio->end_io(dio->iocb, offset, transferred,
251 dio->map_bh.b_private, ret, is_async);
252 } else if (is_async) {
253 aio_complete(dio->iocb, ret, 0);
254 }
255
256 if (dio->flags & DIO_LOCKING)
257
258 up_read_non_owner(&dio->inode->i_alloc_sem);
259
260 return ret;
261}
262
263static int dio_bio_complete(struct dio *dio, struct bio *bio);
264
265
266
267static void dio_bio_end_aio(struct bio *bio, int error)
268{
269 struct dio *dio = bio->bi_private;
270 unsigned long remaining;
271 unsigned long flags;
272
273
274 dio_bio_complete(dio, bio);
275
276 spin_lock_irqsave(&dio->bio_lock, flags);
277 remaining = --dio->refcount;
278 if (remaining == 1 && dio->waiter)
279 wake_up_process(dio->waiter);
280 spin_unlock_irqrestore(&dio->bio_lock, flags);
281
282 if (remaining == 0) {
283 dio_complete(dio, dio->iocb->ki_pos, 0, true);
284 kfree(dio);
285 }
286}
287
288
289
290
291
292
293
294
295static void dio_bio_end_io(struct bio *bio, int error)
296{
297 struct dio *dio = bio->bi_private;
298 unsigned long flags;
299
300 spin_lock_irqsave(&dio->bio_lock, flags);
301 bio->bi_private = dio->bio_list;
302 dio->bio_list = bio;
303 if (--dio->refcount == 1 && dio->waiter)
304 wake_up_process(dio->waiter);
305 spin_unlock_irqrestore(&dio->bio_lock, flags);
306}
307
308
309
310
311
312
313
314
315
316
317void dio_end_io(struct bio *bio, int error)
318{
319 struct dio *dio = bio->bi_private;
320
321 if (dio->is_async)
322 dio_bio_end_aio(bio, error);
323 else
324 dio_bio_end_io(bio, error);
325}
326EXPORT_SYMBOL_GPL(dio_end_io);
327
328static void
329dio_bio_alloc(struct dio *dio, struct block_device *bdev,
330 sector_t first_sector, int nr_vecs)
331{
332 struct bio *bio;
333
334
335
336
337
338 bio = bio_alloc(GFP_KERNEL, nr_vecs);
339
340 bio->bi_bdev = bdev;
341 bio->bi_sector = first_sector;
342 if (dio->is_async)
343 bio->bi_end_io = dio_bio_end_aio;
344 else
345 bio->bi_end_io = dio_bio_end_io;
346
347 dio->bio = bio;
348 dio->logical_offset_in_bio = dio->cur_page_fs_offset;
349}
350
351
352
353
354
355
356
357
358static void dio_bio_submit(struct dio *dio)
359{
360 struct bio *bio = dio->bio;
361 unsigned long flags;
362
363 bio->bi_private = dio;
364
365 spin_lock_irqsave(&dio->bio_lock, flags);
366 dio->refcount++;
367 spin_unlock_irqrestore(&dio->bio_lock, flags);
368
369 if (dio->is_async && dio->rw == READ)
370 bio_set_pages_dirty(bio);
371
372 if (dio->submit_io)
373 dio->submit_io(dio->rw, bio, dio->inode,
374 dio->logical_offset_in_bio);
375 else
376 submit_bio(dio->rw, bio);
377
378 dio->bio = NULL;
379 dio->boundary = 0;
380 dio->logical_offset_in_bio = 0;
381}
382
383
384
385
386static void dio_cleanup(struct dio *dio)
387{
388 while (dio_pages_present(dio))
389 page_cache_release(dio_get_page(dio));
390}
391
392
393
394
395
396
397
398static struct bio *dio_await_one(struct dio *dio)
399{
400 unsigned long flags;
401 struct bio *bio = NULL;
402
403 spin_lock_irqsave(&dio->bio_lock, flags);
404
405
406
407
408
409
410
411 while (dio->refcount > 1 && dio->bio_list == NULL) {
412 __set_current_state(TASK_UNINTERRUPTIBLE);
413 dio->waiter = current;
414 spin_unlock_irqrestore(&dio->bio_lock, flags);
415 io_schedule();
416
417 spin_lock_irqsave(&dio->bio_lock, flags);
418 dio->waiter = NULL;
419 }
420 if (dio->bio_list) {
421 bio = dio->bio_list;
422 dio->bio_list = bio->bi_private;
423 }
424 spin_unlock_irqrestore(&dio->bio_lock, flags);
425 return bio;
426}
427
428
429
430
431static int dio_bio_complete(struct dio *dio, struct bio *bio)
432{
433 const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags);
434 struct bio_vec *bvec = bio->bi_io_vec;
435 int page_no;
436
437 if (!uptodate)
438 dio->io_error = -EIO;
439
440 if (dio->is_async && dio->rw == READ) {
441 bio_check_pages_dirty(bio);
442 } else {
443 for (page_no = 0; page_no < bio->bi_vcnt; page_no++) {
444 struct page *page = bvec[page_no].bv_page;
445
446 if (dio->rw == READ && !PageCompound(page))
447 set_page_dirty_lock(page);
448 page_cache_release(page);
449 }
450 bio_put(bio);
451 }
452 return uptodate ? 0 : -EIO;
453}
454
455
456
457
458
459
460
461
462static void dio_await_completion(struct dio *dio)
463{
464 struct bio *bio;
465 do {
466 bio = dio_await_one(dio);
467 if (bio)
468 dio_bio_complete(dio, bio);
469 } while (bio);
470}
471
472
473
474
475
476
477
478
479static int dio_bio_reap(struct dio *dio)
480{
481 int ret = 0;
482
483 if (dio->reap_counter++ >= 64) {
484 while (dio->bio_list) {
485 unsigned long flags;
486 struct bio *bio;
487 int ret2;
488
489 spin_lock_irqsave(&dio->bio_lock, flags);
490 bio = dio->bio_list;
491 dio->bio_list = bio->bi_private;
492 spin_unlock_irqrestore(&dio->bio_lock, flags);
493 ret2 = dio_bio_complete(dio, bio);
494 if (ret == 0)
495 ret = ret2;
496 }
497 dio->reap_counter = 0;
498 }
499 return ret;
500}
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525static int get_more_blocks(struct dio *dio)
526{
527 int ret;
528 struct buffer_head *map_bh = &dio->map_bh;
529 sector_t fs_startblk;
530 unsigned long fs_count;
531 unsigned long dio_count;
532 unsigned long blkmask;
533 int create;
534
535
536
537
538
539 ret = dio->page_errors;
540 if (ret == 0) {
541 BUG_ON(dio->block_in_file >= dio->final_block_in_request);
542 fs_startblk = dio->block_in_file >> dio->blkfactor;
543 dio_count = dio->final_block_in_request - dio->block_in_file;
544 fs_count = dio_count >> dio->blkfactor;
545 blkmask = (1 << dio->blkfactor) - 1;
546 if (dio_count & blkmask)
547 fs_count++;
548
549 map_bh->b_state = 0;
550 map_bh->b_size = fs_count << dio->inode->i_blkbits;
551
552
553
554
555
556
557
558
559
560
561
562
563 create = dio->rw & WRITE;
564 if (dio->flags & DIO_SKIP_HOLES) {
565 if (dio->block_in_file < (i_size_read(dio->inode) >>
566 dio->blkbits))
567 create = 0;
568 }
569
570 ret = (*dio->get_block)(dio->inode, fs_startblk,
571 map_bh, create);
572 }
573 return ret;
574}
575
576
577
578
579static int dio_new_bio(struct dio *dio, sector_t start_sector)
580{
581 sector_t sector;
582 int ret, nr_pages;
583
584 ret = dio_bio_reap(dio);
585 if (ret)
586 goto out;
587 sector = start_sector << (dio->blkbits - 9);
588 nr_pages = min(dio->pages_in_io, bio_get_nr_vecs(dio->map_bh.b_bdev));
589 nr_pages = min(nr_pages, BIO_MAX_PAGES);
590 BUG_ON(nr_pages <= 0);
591 dio_bio_alloc(dio, dio->map_bh.b_bdev, sector, nr_pages);
592 dio->boundary = 0;
593out:
594 return ret;
595}
596
597
598
599
600
601
602
603
604static int dio_bio_add_page(struct dio *dio)
605{
606 int ret;
607
608 ret = bio_add_page(dio->bio, dio->cur_page,
609 dio->cur_page_len, dio->cur_page_offset);
610 if (ret == dio->cur_page_len) {
611
612
613
614 if ((dio->cur_page_len + dio->cur_page_offset) == PAGE_SIZE)
615 dio->pages_in_io--;
616 page_cache_get(dio->cur_page);
617 dio->final_block_in_bio = dio->cur_page_block +
618 (dio->cur_page_len >> dio->blkbits);
619 ret = 0;
620 } else {
621 ret = 1;
622 }
623 return ret;
624}
625
626
627
628
629
630
631
632
633
634
635
636static int dio_send_cur_page(struct dio *dio)
637{
638 int ret = 0;
639
640 if (dio->bio) {
641 loff_t cur_offset = dio->cur_page_fs_offset;
642 loff_t bio_next_offset = dio->logical_offset_in_bio +
643 dio->bio->bi_size;
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659 if (dio->final_block_in_bio != dio->cur_page_block ||
660 cur_offset != bio_next_offset)
661 dio_bio_submit(dio);
662
663
664
665
666 else if (dio->boundary)
667 dio_bio_submit(dio);
668 }
669
670 if (dio->bio == NULL) {
671 ret = dio_new_bio(dio, dio->cur_page_block);
672 if (ret)
673 goto out;
674 }
675
676 if (dio_bio_add_page(dio) != 0) {
677 dio_bio_submit(dio);
678 ret = dio_new_bio(dio, dio->cur_page_block);
679 if (ret == 0) {
680 ret = dio_bio_add_page(dio);
681 BUG_ON(ret != 0);
682 }
683 }
684out:
685 return ret;
686}
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705static int
706submit_page_section(struct dio *dio, struct page *page,
707 unsigned offset, unsigned len, sector_t blocknr)
708{
709 int ret = 0;
710
711 if (dio->rw & WRITE) {
712
713
714
715 task_io_account_write(len);
716 }
717
718
719
720
721 if ( (dio->cur_page == page) &&
722 (dio->cur_page_offset + dio->cur_page_len == offset) &&
723 (dio->cur_page_block +
724 (dio->cur_page_len >> dio->blkbits) == blocknr)) {
725 dio->cur_page_len += len;
726
727
728
729
730
731 if (dio->boundary) {
732 ret = dio_send_cur_page(dio);
733 page_cache_release(dio->cur_page);
734 dio->cur_page = NULL;
735 }
736 goto out;
737 }
738
739
740
741
742 if (dio->cur_page) {
743 ret = dio_send_cur_page(dio);
744 page_cache_release(dio->cur_page);
745 dio->cur_page = NULL;
746 if (ret)
747 goto out;
748 }
749
750 page_cache_get(page);
751 dio->cur_page = page;
752 dio->cur_page_offset = offset;
753 dio->cur_page_len = len;
754 dio->cur_page_block = blocknr;
755 dio->cur_page_fs_offset = dio->block_in_file << dio->blkbits;
756out:
757 return ret;
758}
759
760
761
762
763
764
765static void clean_blockdev_aliases(struct dio *dio)
766{
767 unsigned i;
768 unsigned nblocks;
769
770 nblocks = dio->map_bh.b_size >> dio->inode->i_blkbits;
771
772 for (i = 0; i < nblocks; i++) {
773 unmap_underlying_metadata(dio->map_bh.b_bdev,
774 dio->map_bh.b_blocknr + i);
775 }
776}
777
778
779
780
781
782
783
784
785
786
787static void dio_zero_block(struct dio *dio, int end)
788{
789 unsigned dio_blocks_per_fs_block;
790 unsigned this_chunk_blocks;
791 unsigned this_chunk_bytes;
792 struct page *page;
793
794 dio->start_zero_done = 1;
795 if (!dio->blkfactor || !buffer_new(&dio->map_bh))
796 return;
797
798 dio_blocks_per_fs_block = 1 << dio->blkfactor;
799 this_chunk_blocks = dio->block_in_file & (dio_blocks_per_fs_block - 1);
800
801 if (!this_chunk_blocks)
802 return;
803
804
805
806
807
808 if (end)
809 this_chunk_blocks = dio_blocks_per_fs_block - this_chunk_blocks;
810
811 this_chunk_bytes = this_chunk_blocks << dio->blkbits;
812
813 page = ZERO_PAGE(0);
814 if (submit_page_section(dio, page, 0, this_chunk_bytes,
815 dio->next_block_for_io))
816 return;
817
818 dio->next_block_for_io += this_chunk_blocks;
819}
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837static int do_direct_IO(struct dio *dio)
838{
839 const unsigned blkbits = dio->blkbits;
840 const unsigned blocks_per_page = PAGE_SIZE >> blkbits;
841 struct page *page;
842 unsigned block_in_page;
843 struct buffer_head *map_bh = &dio->map_bh;
844 int ret = 0;
845
846
847 block_in_page = dio->first_block_in_page;
848
849 while (dio->block_in_file < dio->final_block_in_request) {
850 page = dio_get_page(dio);
851 if (IS_ERR(page)) {
852 ret = PTR_ERR(page);
853 goto out;
854 }
855
856 while (block_in_page < blocks_per_page) {
857 unsigned offset_in_page = block_in_page << blkbits;
858 unsigned this_chunk_bytes;
859 unsigned this_chunk_blocks;
860 unsigned u;
861
862 if (dio->blocks_available == 0) {
863
864
865
866 unsigned long blkmask;
867 unsigned long dio_remainder;
868
869 ret = get_more_blocks(dio);
870 if (ret) {
871 page_cache_release(page);
872 goto out;
873 }
874 if (!buffer_mapped(map_bh))
875 goto do_holes;
876
877 dio->blocks_available =
878 map_bh->b_size >> dio->blkbits;
879 dio->next_block_for_io =
880 map_bh->b_blocknr << dio->blkfactor;
881 if (buffer_new(map_bh))
882 clean_blockdev_aliases(dio);
883
884 if (!dio->blkfactor)
885 goto do_holes;
886
887 blkmask = (1 << dio->blkfactor) - 1;
888 dio_remainder = (dio->block_in_file & blkmask);
889
890
891
892
893
894
895
896
897
898
899
900
901 if (!buffer_new(map_bh))
902 dio->next_block_for_io += dio_remainder;
903 dio->blocks_available -= dio_remainder;
904 }
905do_holes:
906
907 if (!buffer_mapped(map_bh)) {
908 loff_t i_size_aligned;
909
910
911 if (dio->rw & WRITE) {
912 page_cache_release(page);
913 return -ENOTBLK;
914 }
915
916
917
918
919
920 i_size_aligned = ALIGN(i_size_read(dio->inode),
921 1 << blkbits);
922 if (dio->block_in_file >=
923 i_size_aligned >> blkbits) {
924
925 page_cache_release(page);
926 goto out;
927 }
928 zero_user(page, block_in_page << blkbits,
929 1 << blkbits);
930 dio->block_in_file++;
931 block_in_page++;
932 goto next_block;
933 }
934
935
936
937
938
939
940 if (unlikely(dio->blkfactor && !dio->start_zero_done))
941 dio_zero_block(dio, 0);
942
943
944
945
946
947 this_chunk_blocks = dio->blocks_available;
948 u = (PAGE_SIZE - offset_in_page) >> blkbits;
949 if (this_chunk_blocks > u)
950 this_chunk_blocks = u;
951 u = dio->final_block_in_request - dio->block_in_file;
952 if (this_chunk_blocks > u)
953 this_chunk_blocks = u;
954 this_chunk_bytes = this_chunk_blocks << blkbits;
955 BUG_ON(this_chunk_bytes == 0);
956
957 dio->boundary = buffer_boundary(map_bh);
958 ret = submit_page_section(dio, page, offset_in_page,
959 this_chunk_bytes, dio->next_block_for_io);
960 if (ret) {
961 page_cache_release(page);
962 goto out;
963 }
964 dio->next_block_for_io += this_chunk_blocks;
965
966 dio->block_in_file += this_chunk_blocks;
967 block_in_page += this_chunk_blocks;
968 dio->blocks_available -= this_chunk_blocks;
969next_block:
970 BUG_ON(dio->block_in_file > dio->final_block_in_request);
971 if (dio->block_in_file == dio->final_block_in_request)
972 break;
973 }
974
975
976 page_cache_release(page);
977 block_in_page = 0;
978 }
979out:
980 return ret;
981}
982
983
984
985
986static ssize_t
987direct_io_worker(int rw, struct kiocb *iocb, struct inode *inode,
988 const struct iovec *iov, loff_t offset, unsigned long nr_segs,
989 unsigned blkbits, get_block_t get_block, dio_iodone_t end_io,
990 dio_submit_t submit_io, struct dio *dio)
991{
992 unsigned long user_addr;
993 unsigned long flags;
994 int seg;
995 ssize_t ret = 0;
996 ssize_t ret2;
997 size_t bytes;
998
999 dio->inode = inode;
1000 dio->rw = rw;
1001 dio->blkbits = blkbits;
1002 dio->blkfactor = inode->i_blkbits - blkbits;
1003 dio->block_in_file = offset >> blkbits;
1004
1005 dio->get_block = get_block;
1006 dio->end_io = end_io;
1007 dio->submit_io = submit_io;
1008 dio->final_block_in_bio = -1;
1009 dio->next_block_for_io = -1;
1010
1011 dio->iocb = iocb;
1012 dio->i_size = i_size_read(inode);
1013
1014 spin_lock_init(&dio->bio_lock);
1015 dio->refcount = 1;
1016
1017
1018
1019
1020
1021 if (unlikely(dio->blkfactor))
1022 dio->pages_in_io = 2;
1023
1024 for (seg = 0; seg < nr_segs; seg++) {
1025 user_addr = (unsigned long)iov[seg].iov_base;
1026 dio->pages_in_io +=
1027 ((user_addr+iov[seg].iov_len +PAGE_SIZE-1)/PAGE_SIZE
1028 - user_addr/PAGE_SIZE);
1029 }
1030
1031 for (seg = 0; seg < nr_segs; seg++) {
1032 user_addr = (unsigned long)iov[seg].iov_base;
1033 dio->size += bytes = iov[seg].iov_len;
1034
1035
1036 dio->first_block_in_page = (user_addr & ~PAGE_MASK) >> blkbits;
1037 dio->final_block_in_request = dio->block_in_file +
1038 (bytes >> blkbits);
1039
1040 dio->head = 0;
1041 dio->tail = 0;
1042 dio->curr_page = 0;
1043
1044 dio->total_pages = 0;
1045 if (user_addr & (PAGE_SIZE-1)) {
1046 dio->total_pages++;
1047 bytes -= PAGE_SIZE - (user_addr & (PAGE_SIZE - 1));
1048 }
1049 dio->total_pages += (bytes + PAGE_SIZE - 1) / PAGE_SIZE;
1050 dio->curr_user_address = user_addr;
1051
1052 ret = do_direct_IO(dio);
1053
1054 dio->result += iov[seg].iov_len -
1055 ((dio->final_block_in_request - dio->block_in_file) <<
1056 blkbits);
1057
1058 if (ret) {
1059 dio_cleanup(dio);
1060 break;
1061 }
1062 }
1063
1064 if (ret == -ENOTBLK) {
1065
1066
1067
1068
1069 ret = 0;
1070 }
1071
1072
1073
1074
1075 dio_zero_block(dio, 1);
1076
1077 if (dio->cur_page) {
1078 ret2 = dio_send_cur_page(dio);
1079 if (ret == 0)
1080 ret = ret2;
1081 page_cache_release(dio->cur_page);
1082 dio->cur_page = NULL;
1083 }
1084 if (dio->bio)
1085 dio_bio_submit(dio);
1086
1087
1088
1089
1090
1091 dio_cleanup(dio);
1092
1093
1094
1095
1096
1097
1098 if (rw == READ && (dio->flags & DIO_LOCKING))
1099 mutex_unlock(&dio->inode->i_mutex);
1100
1101
1102
1103
1104
1105
1106
1107
1108 BUG_ON(ret == -EIOCBQUEUED);
1109 if (dio->is_async && ret == 0 && dio->result &&
1110 ((rw & READ) || (dio->result == dio->size)))
1111 ret = -EIOCBQUEUED;
1112
1113 if (ret != -EIOCBQUEUED) {
1114
1115 blk_run_address_space(inode->i_mapping);
1116 dio_await_completion(dio);
1117 }
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130 spin_lock_irqsave(&dio->bio_lock, flags);
1131 ret2 = --dio->refcount;
1132 spin_unlock_irqrestore(&dio->bio_lock, flags);
1133
1134 if (ret2 == 0) {
1135 ret = dio_complete(dio, offset, ret, false);
1136 kfree(dio);
1137 } else
1138 BUG_ON(ret != -EIOCBQUEUED);
1139
1140 return ret;
1141}
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162ssize_t
1163__blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
1164 struct block_device *bdev, const struct iovec *iov, loff_t offset,
1165 unsigned long nr_segs, get_block_t get_block, dio_iodone_t end_io,
1166 dio_submit_t submit_io, int flags)
1167{
1168 int seg;
1169 size_t size;
1170 unsigned long addr;
1171 unsigned blkbits = inode->i_blkbits;
1172 unsigned bdev_blkbits = 0;
1173 unsigned blocksize_mask = (1 << blkbits) - 1;
1174 ssize_t retval = -EINVAL;
1175 loff_t end = offset;
1176 struct dio *dio;
1177
1178 if (rw & WRITE)
1179 rw = WRITE_ODIRECT_PLUG;
1180
1181 if (bdev)
1182 bdev_blkbits = blksize_bits(bdev_logical_block_size(bdev));
1183
1184 if (offset & blocksize_mask) {
1185 if (bdev)
1186 blkbits = bdev_blkbits;
1187 blocksize_mask = (1 << blkbits) - 1;
1188 if (offset & blocksize_mask)
1189 goto out;
1190 }
1191
1192
1193 for (seg = 0; seg < nr_segs; seg++) {
1194 addr = (unsigned long)iov[seg].iov_base;
1195 size = iov[seg].iov_len;
1196 end += size;
1197 if ((addr & blocksize_mask) || (size & blocksize_mask)) {
1198 if (bdev)
1199 blkbits = bdev_blkbits;
1200 blocksize_mask = (1 << blkbits) - 1;
1201 if ((addr & blocksize_mask) || (size & blocksize_mask))
1202 goto out;
1203 }
1204 }
1205
1206 dio = kmalloc(sizeof(*dio), GFP_KERNEL);
1207 retval = -ENOMEM;
1208 if (!dio)
1209 goto out;
1210
1211
1212
1213
1214
1215 memset(dio, 0, offsetof(struct dio, pages));
1216
1217 dio->flags = flags;
1218 if (dio->flags & DIO_LOCKING) {
1219
1220 if (rw == READ && end > offset) {
1221 struct address_space *mapping =
1222 iocb->ki_filp->f_mapping;
1223
1224
1225 mutex_lock(&inode->i_mutex);
1226
1227 retval = filemap_write_and_wait_range(mapping, offset,
1228 end - 1);
1229 if (retval) {
1230 mutex_unlock(&inode->i_mutex);
1231 kfree(dio);
1232 goto out;
1233 }
1234 }
1235
1236
1237
1238
1239
1240 down_read_non_owner(&inode->i_alloc_sem);
1241 }
1242
1243
1244
1245
1246
1247
1248
1249 dio->is_async = !is_sync_kiocb(iocb) && !((rw & WRITE) &&
1250 (end > i_size_read(inode)));
1251
1252 retval = direct_io_worker(rw, iocb, inode, iov, offset,
1253 nr_segs, blkbits, get_block, end_io,
1254 submit_io, dio);
1255
1256out:
1257 return retval;
1258}
1259EXPORT_SYMBOL(__blockdev_direct_IO);
1260