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52#include <linux/module.h>
53#include <linux/moduleparam.h>
54#include <linux/sched.h>
55#include <linux/fs.h>
56#include <linux/pagemap.h>
57#include <linux/file.h>
58#include <linux/stat.h>
59#include <linux/errno.h>
60#include <linux/major.h>
61#include <linux/wait.h>
62#include <linux/blkdev.h>
63#include <linux/blkpg.h>
64#include <linux/init.h>
65#include <linux/swap.h>
66#include <linux/slab.h>
67#include <linux/compat.h>
68#include <linux/suspend.h>
69#include <linux/freezer.h>
70#include <linux/mutex.h>
71#include <linux/writeback.h>
72#include <linux/completion.h>
73#include <linux/highmem.h>
74#include <linux/splice.h>
75#include <linux/sysfs.h>
76#include <linux/miscdevice.h>
77#include <linux/falloc.h>
78#include <linux/uio.h>
79#include <linux/ioprio.h>
80#include <linux/blk-cgroup.h>
81#include <linux/sched/mm.h>
82
83#include "loop.h"
84
85#include <linux/uaccess.h>
86
87#define LOOP_IDLE_WORKER_TIMEOUT (60 * HZ)
88
89static DEFINE_IDR(loop_index_idr);
90static DEFINE_MUTEX(loop_ctl_mutex);
91static DEFINE_MUTEX(loop_validate_mutex);
92
93
94
95
96
97
98
99
100
101
102
103
104
105static int loop_global_lock_killable(struct loop_device *lo, bool global)
106{
107 int err;
108
109 if (global) {
110 err = mutex_lock_killable(&loop_validate_mutex);
111 if (err)
112 return err;
113 }
114 err = mutex_lock_killable(&lo->lo_mutex);
115 if (err && global)
116 mutex_unlock(&loop_validate_mutex);
117 return err;
118}
119
120
121
122
123
124
125
126static void loop_global_unlock(struct loop_device *lo, bool global)
127{
128 mutex_unlock(&lo->lo_mutex);
129 if (global)
130 mutex_unlock(&loop_validate_mutex);
131}
132
133static int max_part;
134static int part_shift;
135
136static int transfer_xor(struct loop_device *lo, int cmd,
137 struct page *raw_page, unsigned raw_off,
138 struct page *loop_page, unsigned loop_off,
139 int size, sector_t real_block)
140{
141 char *raw_buf = kmap_atomic(raw_page) + raw_off;
142 char *loop_buf = kmap_atomic(loop_page) + loop_off;
143 char *in, *out, *key;
144 int i, keysize;
145
146 if (cmd == READ) {
147 in = raw_buf;
148 out = loop_buf;
149 } else {
150 in = loop_buf;
151 out = raw_buf;
152 }
153
154 key = lo->lo_encrypt_key;
155 keysize = lo->lo_encrypt_key_size;
156 for (i = 0; i < size; i++)
157 *out++ = *in++ ^ key[(i & 511) % keysize];
158
159 kunmap_atomic(loop_buf);
160 kunmap_atomic(raw_buf);
161 cond_resched();
162 return 0;
163}
164
165static int xor_init(struct loop_device *lo, const struct loop_info64 *info)
166{
167 if (unlikely(info->lo_encrypt_key_size <= 0))
168 return -EINVAL;
169 return 0;
170}
171
172static struct loop_func_table none_funcs = {
173 .number = LO_CRYPT_NONE,
174};
175
176static struct loop_func_table xor_funcs = {
177 .number = LO_CRYPT_XOR,
178 .transfer = transfer_xor,
179 .init = xor_init
180};
181
182
183static struct loop_func_table *xfer_funcs[MAX_LO_CRYPT] = {
184 &none_funcs,
185 &xor_funcs
186};
187
188static loff_t get_size(loff_t offset, loff_t sizelimit, struct file *file)
189{
190 loff_t loopsize;
191
192
193 loopsize = i_size_read(file->f_mapping->host);
194 if (offset > 0)
195 loopsize -= offset;
196
197 if (loopsize < 0)
198 return 0;
199
200 if (sizelimit > 0 && sizelimit < loopsize)
201 loopsize = sizelimit;
202
203
204
205
206 return loopsize >> 9;
207}
208
209static loff_t get_loop_size(struct loop_device *lo, struct file *file)
210{
211 return get_size(lo->lo_offset, lo->lo_sizelimit, file);
212}
213
214static void __loop_update_dio(struct loop_device *lo, bool dio)
215{
216 struct file *file = lo->lo_backing_file;
217 struct address_space *mapping = file->f_mapping;
218 struct inode *inode = mapping->host;
219 unsigned short sb_bsize = 0;
220 unsigned dio_align = 0;
221 bool use_dio;
222
223 if (inode->i_sb->s_bdev) {
224 sb_bsize = bdev_logical_block_size(inode->i_sb->s_bdev);
225 dio_align = sb_bsize - 1;
226 }
227
228
229
230
231
232
233
234
235
236
237
238 if (dio) {
239 if (queue_logical_block_size(lo->lo_queue) >= sb_bsize &&
240 !(lo->lo_offset & dio_align) &&
241 mapping->a_ops->direct_IO &&
242 !lo->transfer)
243 use_dio = true;
244 else
245 use_dio = false;
246 } else {
247 use_dio = false;
248 }
249
250 if (lo->use_dio == use_dio)
251 return;
252
253
254 vfs_fsync(file, 0);
255
256
257
258
259
260
261 if (lo->lo_state == Lo_bound)
262 blk_mq_freeze_queue(lo->lo_queue);
263 lo->use_dio = use_dio;
264 if (use_dio) {
265 blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, lo->lo_queue);
266 lo->lo_flags |= LO_FLAGS_DIRECT_IO;
267 } else {
268 blk_queue_flag_set(QUEUE_FLAG_NOMERGES, lo->lo_queue);
269 lo->lo_flags &= ~LO_FLAGS_DIRECT_IO;
270 }
271 if (lo->lo_state == Lo_bound)
272 blk_mq_unfreeze_queue(lo->lo_queue);
273}
274
275
276
277
278
279static int
280loop_validate_block_size(unsigned short bsize)
281{
282 if (bsize < 512 || bsize > PAGE_SIZE || !is_power_of_2(bsize))
283 return -EINVAL;
284
285 return 0;
286}
287
288
289
290
291
292
293
294
295
296static void loop_set_size(struct loop_device *lo, loff_t size)
297{
298 if (!set_capacity_and_notify(lo->lo_disk, size))
299 kobject_uevent(&disk_to_dev(lo->lo_disk)->kobj, KOBJ_CHANGE);
300}
301
302static inline int
303lo_do_transfer(struct loop_device *lo, int cmd,
304 struct page *rpage, unsigned roffs,
305 struct page *lpage, unsigned loffs,
306 int size, sector_t rblock)
307{
308 int ret;
309
310 ret = lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock);
311 if (likely(!ret))
312 return 0;
313
314 printk_ratelimited(KERN_ERR
315 "loop: Transfer error at byte offset %llu, length %i.\n",
316 (unsigned long long)rblock << 9, size);
317 return ret;
318}
319
320static int lo_write_bvec(struct file *file, struct bio_vec *bvec, loff_t *ppos)
321{
322 struct iov_iter i;
323 ssize_t bw;
324
325 iov_iter_bvec(&i, WRITE, bvec, 1, bvec->bv_len);
326
327 file_start_write(file);
328 bw = vfs_iter_write(file, &i, ppos, 0);
329 file_end_write(file);
330
331 if (likely(bw == bvec->bv_len))
332 return 0;
333
334 printk_ratelimited(KERN_ERR
335 "loop: Write error at byte offset %llu, length %i.\n",
336 (unsigned long long)*ppos, bvec->bv_len);
337 if (bw >= 0)
338 bw = -EIO;
339 return bw;
340}
341
342static int lo_write_simple(struct loop_device *lo, struct request *rq,
343 loff_t pos)
344{
345 struct bio_vec bvec;
346 struct req_iterator iter;
347 int ret = 0;
348
349 rq_for_each_segment(bvec, rq, iter) {
350 ret = lo_write_bvec(lo->lo_backing_file, &bvec, &pos);
351 if (ret < 0)
352 break;
353 cond_resched();
354 }
355
356 return ret;
357}
358
359
360
361
362
363
364static int lo_write_transfer(struct loop_device *lo, struct request *rq,
365 loff_t pos)
366{
367 struct bio_vec bvec, b;
368 struct req_iterator iter;
369 struct page *page;
370 int ret = 0;
371
372 page = alloc_page(GFP_NOIO);
373 if (unlikely(!page))
374 return -ENOMEM;
375
376 rq_for_each_segment(bvec, rq, iter) {
377 ret = lo_do_transfer(lo, WRITE, page, 0, bvec.bv_page,
378 bvec.bv_offset, bvec.bv_len, pos >> 9);
379 if (unlikely(ret))
380 break;
381
382 b.bv_page = page;
383 b.bv_offset = 0;
384 b.bv_len = bvec.bv_len;
385 ret = lo_write_bvec(lo->lo_backing_file, &b, &pos);
386 if (ret < 0)
387 break;
388 }
389
390 __free_page(page);
391 return ret;
392}
393
394static int lo_read_simple(struct loop_device *lo, struct request *rq,
395 loff_t pos)
396{
397 struct bio_vec bvec;
398 struct req_iterator iter;
399 struct iov_iter i;
400 ssize_t len;
401
402 rq_for_each_segment(bvec, rq, iter) {
403 iov_iter_bvec(&i, READ, &bvec, 1, bvec.bv_len);
404 len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0);
405 if (len < 0)
406 return len;
407
408 flush_dcache_page(bvec.bv_page);
409
410 if (len != bvec.bv_len) {
411 struct bio *bio;
412
413 __rq_for_each_bio(bio, rq)
414 zero_fill_bio(bio);
415 break;
416 }
417 cond_resched();
418 }
419
420 return 0;
421}
422
423static int lo_read_transfer(struct loop_device *lo, struct request *rq,
424 loff_t pos)
425{
426 struct bio_vec bvec, b;
427 struct req_iterator iter;
428 struct iov_iter i;
429 struct page *page;
430 ssize_t len;
431 int ret = 0;
432
433 page = alloc_page(GFP_NOIO);
434 if (unlikely(!page))
435 return -ENOMEM;
436
437 rq_for_each_segment(bvec, rq, iter) {
438 loff_t offset = pos;
439
440 b.bv_page = page;
441 b.bv_offset = 0;
442 b.bv_len = bvec.bv_len;
443
444 iov_iter_bvec(&i, READ, &b, 1, b.bv_len);
445 len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0);
446 if (len < 0) {
447 ret = len;
448 goto out_free_page;
449 }
450
451 ret = lo_do_transfer(lo, READ, page, 0, bvec.bv_page,
452 bvec.bv_offset, len, offset >> 9);
453 if (ret)
454 goto out_free_page;
455
456 flush_dcache_page(bvec.bv_page);
457
458 if (len != bvec.bv_len) {
459 struct bio *bio;
460
461 __rq_for_each_bio(bio, rq)
462 zero_fill_bio(bio);
463 break;
464 }
465 }
466
467 ret = 0;
468out_free_page:
469 __free_page(page);
470 return ret;
471}
472
473static int lo_fallocate(struct loop_device *lo, struct request *rq, loff_t pos,
474 int mode)
475{
476
477
478
479
480
481
482 struct file *file = lo->lo_backing_file;
483 struct request_queue *q = lo->lo_queue;
484 int ret;
485
486 mode |= FALLOC_FL_KEEP_SIZE;
487
488 if (!blk_queue_discard(q)) {
489 ret = -EOPNOTSUPP;
490 goto out;
491 }
492
493 ret = file->f_op->fallocate(file, mode, pos, blk_rq_bytes(rq));
494 if (unlikely(ret && ret != -EINVAL && ret != -EOPNOTSUPP))
495 ret = -EIO;
496 out:
497 return ret;
498}
499
500static int lo_req_flush(struct loop_device *lo, struct request *rq)
501{
502 struct file *file = lo->lo_backing_file;
503 int ret = vfs_fsync(file, 0);
504 if (unlikely(ret && ret != -EINVAL))
505 ret = -EIO;
506
507 return ret;
508}
509
510static void lo_complete_rq(struct request *rq)
511{
512 struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq);
513 blk_status_t ret = BLK_STS_OK;
514
515 if (!cmd->use_aio || cmd->ret < 0 || cmd->ret == blk_rq_bytes(rq) ||
516 req_op(rq) != REQ_OP_READ) {
517 if (cmd->ret < 0)
518 ret = errno_to_blk_status(cmd->ret);
519 goto end_io;
520 }
521
522
523
524
525
526 if (cmd->ret) {
527 blk_update_request(rq, BLK_STS_OK, cmd->ret);
528 cmd->ret = 0;
529 blk_mq_requeue_request(rq, true);
530 } else {
531 if (cmd->use_aio) {
532 struct bio *bio = rq->bio;
533
534 while (bio) {
535 zero_fill_bio(bio);
536 bio = bio->bi_next;
537 }
538 }
539 ret = BLK_STS_IOERR;
540end_io:
541 blk_mq_end_request(rq, ret);
542 }
543}
544
545static void lo_rw_aio_do_completion(struct loop_cmd *cmd)
546{
547 struct request *rq = blk_mq_rq_from_pdu(cmd);
548
549 if (!atomic_dec_and_test(&cmd->ref))
550 return;
551 kfree(cmd->bvec);
552 cmd->bvec = NULL;
553 if (likely(!blk_should_fake_timeout(rq->q)))
554 blk_mq_complete_request(rq);
555}
556
557static void lo_rw_aio_complete(struct kiocb *iocb, long ret, long ret2)
558{
559 struct loop_cmd *cmd = container_of(iocb, struct loop_cmd, iocb);
560
561 cmd->ret = ret;
562 lo_rw_aio_do_completion(cmd);
563}
564
565static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd,
566 loff_t pos, bool rw)
567{
568 struct iov_iter iter;
569 struct req_iterator rq_iter;
570 struct bio_vec *bvec;
571 struct request *rq = blk_mq_rq_from_pdu(cmd);
572 struct bio *bio = rq->bio;
573 struct file *file = lo->lo_backing_file;
574 struct bio_vec tmp;
575 unsigned int offset;
576 int nr_bvec = 0;
577 int ret;
578
579 rq_for_each_bvec(tmp, rq, rq_iter)
580 nr_bvec++;
581
582 if (rq->bio != rq->biotail) {
583
584 bvec = kmalloc_array(nr_bvec, sizeof(struct bio_vec),
585 GFP_NOIO);
586 if (!bvec)
587 return -EIO;
588 cmd->bvec = bvec;
589
590
591
592
593
594
595
596 rq_for_each_bvec(tmp, rq, rq_iter) {
597 *bvec = tmp;
598 bvec++;
599 }
600 bvec = cmd->bvec;
601 offset = 0;
602 } else {
603
604
605
606
607
608 offset = bio->bi_iter.bi_bvec_done;
609 bvec = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter);
610 }
611 atomic_set(&cmd->ref, 2);
612
613 iov_iter_bvec(&iter, rw, bvec, nr_bvec, blk_rq_bytes(rq));
614 iter.iov_offset = offset;
615
616 cmd->iocb.ki_pos = pos;
617 cmd->iocb.ki_filp = file;
618 cmd->iocb.ki_complete = lo_rw_aio_complete;
619 cmd->iocb.ki_flags = IOCB_DIRECT;
620 cmd->iocb.ki_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, 0);
621
622 if (rw == WRITE)
623 ret = call_write_iter(file, &cmd->iocb, &iter);
624 else
625 ret = call_read_iter(file, &cmd->iocb, &iter);
626
627 lo_rw_aio_do_completion(cmd);
628
629 if (ret != -EIOCBQUEUED)
630 cmd->iocb.ki_complete(&cmd->iocb, ret, 0);
631 return 0;
632}
633
634static int do_req_filebacked(struct loop_device *lo, struct request *rq)
635{
636 struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq);
637 loff_t pos = ((loff_t) blk_rq_pos(rq) << 9) + lo->lo_offset;
638
639
640
641
642
643
644
645
646
647
648 switch (req_op(rq)) {
649 case REQ_OP_FLUSH:
650 return lo_req_flush(lo, rq);
651 case REQ_OP_WRITE_ZEROES:
652
653
654
655
656 return lo_fallocate(lo, rq, pos,
657 (rq->cmd_flags & REQ_NOUNMAP) ?
658 FALLOC_FL_ZERO_RANGE :
659 FALLOC_FL_PUNCH_HOLE);
660 case REQ_OP_DISCARD:
661 return lo_fallocate(lo, rq, pos, FALLOC_FL_PUNCH_HOLE);
662 case REQ_OP_WRITE:
663 if (lo->transfer)
664 return lo_write_transfer(lo, rq, pos);
665 else if (cmd->use_aio)
666 return lo_rw_aio(lo, cmd, pos, WRITE);
667 else
668 return lo_write_simple(lo, rq, pos);
669 case REQ_OP_READ:
670 if (lo->transfer)
671 return lo_read_transfer(lo, rq, pos);
672 else if (cmd->use_aio)
673 return lo_rw_aio(lo, cmd, pos, READ);
674 else
675 return lo_read_simple(lo, rq, pos);
676 default:
677 WARN_ON_ONCE(1);
678 return -EIO;
679 }
680}
681
682static inline void loop_update_dio(struct loop_device *lo)
683{
684 __loop_update_dio(lo, (lo->lo_backing_file->f_flags & O_DIRECT) |
685 lo->use_dio);
686}
687
688static void loop_reread_partitions(struct loop_device *lo)
689{
690 int rc;
691
692 mutex_lock(&lo->lo_disk->open_mutex);
693 rc = bdev_disk_changed(lo->lo_disk, false);
694 mutex_unlock(&lo->lo_disk->open_mutex);
695 if (rc)
696 pr_warn("%s: partition scan of loop%d (%s) failed (rc=%d)\n",
697 __func__, lo->lo_number, lo->lo_file_name, rc);
698}
699
700static inline int is_loop_device(struct file *file)
701{
702 struct inode *i = file->f_mapping->host;
703
704 return i && S_ISBLK(i->i_mode) && imajor(i) == LOOP_MAJOR;
705}
706
707static int loop_validate_file(struct file *file, struct block_device *bdev)
708{
709 struct inode *inode = file->f_mapping->host;
710 struct file *f = file;
711
712
713 while (is_loop_device(f)) {
714 struct loop_device *l;
715
716 lockdep_assert_held(&loop_validate_mutex);
717 if (f->f_mapping->host->i_rdev == bdev->bd_dev)
718 return -EBADF;
719
720 l = I_BDEV(f->f_mapping->host)->bd_disk->private_data;
721 if (l->lo_state != Lo_bound)
722 return -EINVAL;
723
724 rmb();
725 f = l->lo_backing_file;
726 }
727 if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))
728 return -EINVAL;
729 return 0;
730}
731
732
733
734
735
736
737
738
739
740static int loop_change_fd(struct loop_device *lo, struct block_device *bdev,
741 unsigned int arg)
742{
743 struct file *file = fget(arg);
744 struct file *old_file;
745 int error;
746 bool partscan;
747 bool is_loop;
748
749 if (!file)
750 return -EBADF;
751 is_loop = is_loop_device(file);
752 error = loop_global_lock_killable(lo, is_loop);
753 if (error)
754 goto out_putf;
755 error = -ENXIO;
756 if (lo->lo_state != Lo_bound)
757 goto out_err;
758
759
760 error = -EINVAL;
761 if (!(lo->lo_flags & LO_FLAGS_READ_ONLY))
762 goto out_err;
763
764 error = loop_validate_file(file, bdev);
765 if (error)
766 goto out_err;
767
768 old_file = lo->lo_backing_file;
769
770 error = -EINVAL;
771
772
773 if (get_loop_size(lo, file) != get_loop_size(lo, old_file))
774 goto out_err;
775
776
777 blk_mq_freeze_queue(lo->lo_queue);
778 mapping_set_gfp_mask(old_file->f_mapping, lo->old_gfp_mask);
779 lo->lo_backing_file = file;
780 lo->old_gfp_mask = mapping_gfp_mask(file->f_mapping);
781 mapping_set_gfp_mask(file->f_mapping,
782 lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));
783 loop_update_dio(lo);
784 blk_mq_unfreeze_queue(lo->lo_queue);
785 partscan = lo->lo_flags & LO_FLAGS_PARTSCAN;
786 loop_global_unlock(lo, is_loop);
787
788
789
790
791
792 if (!is_loop) {
793 mutex_lock(&loop_validate_mutex);
794 mutex_unlock(&loop_validate_mutex);
795 }
796
797
798
799
800
801 fput(old_file);
802 if (partscan)
803 loop_reread_partitions(lo);
804 return 0;
805
806out_err:
807 loop_global_unlock(lo, is_loop);
808out_putf:
809 fput(file);
810 return error;
811}
812
813
814
815static ssize_t loop_attr_show(struct device *dev, char *page,
816 ssize_t (*callback)(struct loop_device *, char *))
817{
818 struct gendisk *disk = dev_to_disk(dev);
819 struct loop_device *lo = disk->private_data;
820
821 return callback(lo, page);
822}
823
824#define LOOP_ATTR_RO(_name) \
825static ssize_t loop_attr_##_name##_show(struct loop_device *, char *); \
826static ssize_t loop_attr_do_show_##_name(struct device *d, \
827 struct device_attribute *attr, char *b) \
828{ \
829 return loop_attr_show(d, b, loop_attr_##_name##_show); \
830} \
831static struct device_attribute loop_attr_##_name = \
832 __ATTR(_name, 0444, loop_attr_do_show_##_name, NULL);
833
834static ssize_t loop_attr_backing_file_show(struct loop_device *lo, char *buf)
835{
836 ssize_t ret;
837 char *p = NULL;
838
839 spin_lock_irq(&lo->lo_lock);
840 if (lo->lo_backing_file)
841 p = file_path(lo->lo_backing_file, buf, PAGE_SIZE - 1);
842 spin_unlock_irq(&lo->lo_lock);
843
844 if (IS_ERR_OR_NULL(p))
845 ret = PTR_ERR(p);
846 else {
847 ret = strlen(p);
848 memmove(buf, p, ret);
849 buf[ret++] = '\n';
850 buf[ret] = 0;
851 }
852
853 return ret;
854}
855
856static ssize_t loop_attr_offset_show(struct loop_device *lo, char *buf)
857{
858 return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_offset);
859}
860
861static ssize_t loop_attr_sizelimit_show(struct loop_device *lo, char *buf)
862{
863 return sprintf(buf, "%llu\n", (unsigned long long)lo->lo_sizelimit);
864}
865
866static ssize_t loop_attr_autoclear_show(struct loop_device *lo, char *buf)
867{
868 int autoclear = (lo->lo_flags & LO_FLAGS_AUTOCLEAR);
869
870 return sprintf(buf, "%s\n", autoclear ? "1" : "0");
871}
872
873static ssize_t loop_attr_partscan_show(struct loop_device *lo, char *buf)
874{
875 int partscan = (lo->lo_flags & LO_FLAGS_PARTSCAN);
876
877 return sprintf(buf, "%s\n", partscan ? "1" : "0");
878}
879
880static ssize_t loop_attr_dio_show(struct loop_device *lo, char *buf)
881{
882 int dio = (lo->lo_flags & LO_FLAGS_DIRECT_IO);
883
884 return sprintf(buf, "%s\n", dio ? "1" : "0");
885}
886
887LOOP_ATTR_RO(backing_file);
888LOOP_ATTR_RO(offset);
889LOOP_ATTR_RO(sizelimit);
890LOOP_ATTR_RO(autoclear);
891LOOP_ATTR_RO(partscan);
892LOOP_ATTR_RO(dio);
893
894static struct attribute *loop_attrs[] = {
895 &loop_attr_backing_file.attr,
896 &loop_attr_offset.attr,
897 &loop_attr_sizelimit.attr,
898 &loop_attr_autoclear.attr,
899 &loop_attr_partscan.attr,
900 &loop_attr_dio.attr,
901 NULL,
902};
903
904static struct attribute_group loop_attribute_group = {
905 .name = "loop",
906 .attrs= loop_attrs,
907};
908
909static void loop_sysfs_init(struct loop_device *lo)
910{
911 lo->sysfs_inited = !sysfs_create_group(&disk_to_dev(lo->lo_disk)->kobj,
912 &loop_attribute_group);
913}
914
915static void loop_sysfs_exit(struct loop_device *lo)
916{
917 if (lo->sysfs_inited)
918 sysfs_remove_group(&disk_to_dev(lo->lo_disk)->kobj,
919 &loop_attribute_group);
920}
921
922static void loop_config_discard(struct loop_device *lo)
923{
924 struct file *file = lo->lo_backing_file;
925 struct inode *inode = file->f_mapping->host;
926 struct request_queue *q = lo->lo_queue;
927 u32 granularity, max_discard_sectors;
928
929
930
931
932
933
934
935
936 if (S_ISBLK(inode->i_mode) && !lo->lo_encrypt_key_size) {
937 struct request_queue *backingq = bdev_get_queue(I_BDEV(inode));
938
939 max_discard_sectors = backingq->limits.max_write_zeroes_sectors;
940 granularity = backingq->limits.discard_granularity ?:
941 queue_physical_block_size(backingq);
942
943
944
945
946
947
948
949 } else if (!file->f_op->fallocate || lo->lo_encrypt_key_size) {
950 max_discard_sectors = 0;
951 granularity = 0;
952
953 } else {
954 max_discard_sectors = UINT_MAX >> 9;
955 granularity = inode->i_sb->s_blocksize;
956 }
957
958 if (max_discard_sectors) {
959 q->limits.discard_granularity = granularity;
960 blk_queue_max_discard_sectors(q, max_discard_sectors);
961 blk_queue_max_write_zeroes_sectors(q, max_discard_sectors);
962 blk_queue_flag_set(QUEUE_FLAG_DISCARD, q);
963 } else {
964 q->limits.discard_granularity = 0;
965 blk_queue_max_discard_sectors(q, 0);
966 blk_queue_max_write_zeroes_sectors(q, 0);
967 blk_queue_flag_clear(QUEUE_FLAG_DISCARD, q);
968 }
969 q->limits.discard_alignment = 0;
970}
971
972struct loop_worker {
973 struct rb_node rb_node;
974 struct work_struct work;
975 struct list_head cmd_list;
976 struct list_head idle_list;
977 struct loop_device *lo;
978 struct cgroup_subsys_state *blkcg_css;
979 unsigned long last_ran_at;
980};
981
982static void loop_workfn(struct work_struct *work);
983static void loop_rootcg_workfn(struct work_struct *work);
984static void loop_free_idle_workers(struct timer_list *timer);
985
986#ifdef CONFIG_BLK_CGROUP
987static inline int queue_on_root_worker(struct cgroup_subsys_state *css)
988{
989 return !css || css == blkcg_root_css;
990}
991#else
992static inline int queue_on_root_worker(struct cgroup_subsys_state *css)
993{
994 return !css;
995}
996#endif
997
998static void loop_queue_work(struct loop_device *lo, struct loop_cmd *cmd)
999{
1000 struct rb_node **node = &(lo->worker_tree.rb_node), *parent = NULL;
1001 struct loop_worker *cur_worker, *worker = NULL;
1002 struct work_struct *work;
1003 struct list_head *cmd_list;
1004
1005 spin_lock_irq(&lo->lo_work_lock);
1006
1007 if (queue_on_root_worker(cmd->blkcg_css))
1008 goto queue_work;
1009
1010 node = &lo->worker_tree.rb_node;
1011
1012 while (*node) {
1013 parent = *node;
1014 cur_worker = container_of(*node, struct loop_worker, rb_node);
1015 if (cur_worker->blkcg_css == cmd->blkcg_css) {
1016 worker = cur_worker;
1017 break;
1018 } else if ((long)cur_worker->blkcg_css < (long)cmd->blkcg_css) {
1019 node = &(*node)->rb_left;
1020 } else {
1021 node = &(*node)->rb_right;
1022 }
1023 }
1024 if (worker)
1025 goto queue_work;
1026
1027 worker = kzalloc(sizeof(struct loop_worker), GFP_NOWAIT | __GFP_NOWARN);
1028
1029
1030
1031
1032 if (!worker) {
1033 cmd->blkcg_css = NULL;
1034 if (cmd->memcg_css)
1035 css_put(cmd->memcg_css);
1036 cmd->memcg_css = NULL;
1037 goto queue_work;
1038 }
1039
1040 worker->blkcg_css = cmd->blkcg_css;
1041 css_get(worker->blkcg_css);
1042 INIT_WORK(&worker->work, loop_workfn);
1043 INIT_LIST_HEAD(&worker->cmd_list);
1044 INIT_LIST_HEAD(&worker->idle_list);
1045 worker->lo = lo;
1046 rb_link_node(&worker->rb_node, parent, node);
1047 rb_insert_color(&worker->rb_node, &lo->worker_tree);
1048queue_work:
1049 if (worker) {
1050
1051
1052
1053
1054
1055 if (!list_empty(&worker->idle_list))
1056 list_del_init(&worker->idle_list);
1057 work = &worker->work;
1058 cmd_list = &worker->cmd_list;
1059 } else {
1060 work = &lo->rootcg_work;
1061 cmd_list = &lo->rootcg_cmd_list;
1062 }
1063 list_add_tail(&cmd->list_entry, cmd_list);
1064 queue_work(lo->workqueue, work);
1065 spin_unlock_irq(&lo->lo_work_lock);
1066}
1067
1068static void loop_update_rotational(struct loop_device *lo)
1069{
1070 struct file *file = lo->lo_backing_file;
1071 struct inode *file_inode = file->f_mapping->host;
1072 struct block_device *file_bdev = file_inode->i_sb->s_bdev;
1073 struct request_queue *q = lo->lo_queue;
1074 bool nonrot = true;
1075
1076
1077 if (file_bdev)
1078 nonrot = blk_queue_nonrot(bdev_get_queue(file_bdev));
1079
1080 if (nonrot)
1081 blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
1082 else
1083 blk_queue_flag_clear(QUEUE_FLAG_NONROT, q);
1084}
1085
1086static int
1087loop_release_xfer(struct loop_device *lo)
1088{
1089 int err = 0;
1090 struct loop_func_table *xfer = lo->lo_encryption;
1091
1092 if (xfer) {
1093 if (xfer->release)
1094 err = xfer->release(lo);
1095 lo->transfer = NULL;
1096 lo->lo_encryption = NULL;
1097 module_put(xfer->owner);
1098 }
1099 return err;
1100}
1101
1102static int
1103loop_init_xfer(struct loop_device *lo, struct loop_func_table *xfer,
1104 const struct loop_info64 *i)
1105{
1106 int err = 0;
1107
1108 if (xfer) {
1109 struct module *owner = xfer->owner;
1110
1111 if (!try_module_get(owner))
1112 return -EINVAL;
1113 if (xfer->init)
1114 err = xfer->init(lo, i);
1115 if (err)
1116 module_put(owner);
1117 else
1118 lo->lo_encryption = xfer;
1119 }
1120 return err;
1121}
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131static int
1132loop_set_status_from_info(struct loop_device *lo,
1133 const struct loop_info64 *info)
1134{
1135 int err;
1136 struct loop_func_table *xfer;
1137 kuid_t uid = current_uid();
1138
1139 if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE)
1140 return -EINVAL;
1141
1142 err = loop_release_xfer(lo);
1143 if (err)
1144 return err;
1145
1146 if (info->lo_encrypt_type) {
1147 unsigned int type = info->lo_encrypt_type;
1148
1149 if (type >= MAX_LO_CRYPT)
1150 return -EINVAL;
1151 xfer = xfer_funcs[type];
1152 if (xfer == NULL)
1153 return -EINVAL;
1154 } else
1155 xfer = NULL;
1156
1157 err = loop_init_xfer(lo, xfer, info);
1158 if (err)
1159 return err;
1160
1161 lo->lo_offset = info->lo_offset;
1162 lo->lo_sizelimit = info->lo_sizelimit;
1163 memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE);
1164 memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE);
1165 lo->lo_file_name[LO_NAME_SIZE-1] = 0;
1166 lo->lo_crypt_name[LO_NAME_SIZE-1] = 0;
1167
1168 if (!xfer)
1169 xfer = &none_funcs;
1170 lo->transfer = xfer->transfer;
1171 lo->ioctl = xfer->ioctl;
1172
1173 lo->lo_flags = info->lo_flags;
1174
1175 lo->lo_encrypt_key_size = info->lo_encrypt_key_size;
1176 lo->lo_init[0] = info->lo_init[0];
1177 lo->lo_init[1] = info->lo_init[1];
1178 if (info->lo_encrypt_key_size) {
1179 memcpy(lo->lo_encrypt_key, info->lo_encrypt_key,
1180 info->lo_encrypt_key_size);
1181 lo->lo_key_owner = uid;
1182 }
1183
1184 return 0;
1185}
1186
1187static int loop_configure(struct loop_device *lo, fmode_t mode,
1188 struct block_device *bdev,
1189 const struct loop_config *config)
1190{
1191 struct file *file = fget(config->fd);
1192 struct inode *inode;
1193 struct address_space *mapping;
1194 int error;
1195 loff_t size;
1196 bool partscan;
1197 unsigned short bsize;
1198 bool is_loop;
1199
1200 if (!file)
1201 return -EBADF;
1202 is_loop = is_loop_device(file);
1203
1204
1205 __module_get(THIS_MODULE);
1206
1207
1208
1209
1210
1211 if (!(mode & FMODE_EXCL)) {
1212 error = bd_prepare_to_claim(bdev, loop_configure);
1213 if (error)
1214 goto out_putf;
1215 }
1216
1217 error = loop_global_lock_killable(lo, is_loop);
1218 if (error)
1219 goto out_bdev;
1220
1221 error = -EBUSY;
1222 if (lo->lo_state != Lo_unbound)
1223 goto out_unlock;
1224
1225 error = loop_validate_file(file, bdev);
1226 if (error)
1227 goto out_unlock;
1228
1229 mapping = file->f_mapping;
1230 inode = mapping->host;
1231
1232 if ((config->info.lo_flags & ~LOOP_CONFIGURE_SETTABLE_FLAGS) != 0) {
1233 error = -EINVAL;
1234 goto out_unlock;
1235 }
1236
1237 if (config->block_size) {
1238 error = loop_validate_block_size(config->block_size);
1239 if (error)
1240 goto out_unlock;
1241 }
1242
1243 error = loop_set_status_from_info(lo, &config->info);
1244 if (error)
1245 goto out_unlock;
1246
1247 if (!(file->f_mode & FMODE_WRITE) || !(mode & FMODE_WRITE) ||
1248 !file->f_op->write_iter)
1249 lo->lo_flags |= LO_FLAGS_READ_ONLY;
1250
1251 lo->workqueue = alloc_workqueue("loop%d",
1252 WQ_UNBOUND | WQ_FREEZABLE,
1253 0,
1254 lo->lo_number);
1255 if (!lo->workqueue) {
1256 error = -ENOMEM;
1257 goto out_unlock;
1258 }
1259
1260 set_disk_ro(lo->lo_disk, (lo->lo_flags & LO_FLAGS_READ_ONLY) != 0);
1261
1262 INIT_WORK(&lo->rootcg_work, loop_rootcg_workfn);
1263 INIT_LIST_HEAD(&lo->rootcg_cmd_list);
1264 INIT_LIST_HEAD(&lo->idle_worker_list);
1265 lo->worker_tree = RB_ROOT;
1266 timer_setup(&lo->timer, loop_free_idle_workers,
1267 TIMER_DEFERRABLE);
1268 lo->use_dio = lo->lo_flags & LO_FLAGS_DIRECT_IO;
1269 lo->lo_device = bdev;
1270 lo->lo_backing_file = file;
1271 lo->old_gfp_mask = mapping_gfp_mask(mapping);
1272 mapping_set_gfp_mask(mapping, lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));
1273
1274 if (!(lo->lo_flags & LO_FLAGS_READ_ONLY) && file->f_op->fsync)
1275 blk_queue_write_cache(lo->lo_queue, true, false);
1276
1277 if (config->block_size)
1278 bsize = config->block_size;
1279 else if ((lo->lo_backing_file->f_flags & O_DIRECT) && inode->i_sb->s_bdev)
1280
1281 bsize = bdev_logical_block_size(inode->i_sb->s_bdev);
1282 else
1283 bsize = 512;
1284
1285 blk_queue_logical_block_size(lo->lo_queue, bsize);
1286 blk_queue_physical_block_size(lo->lo_queue, bsize);
1287 blk_queue_io_min(lo->lo_queue, bsize);
1288
1289 loop_config_discard(lo);
1290 loop_update_rotational(lo);
1291 loop_update_dio(lo);
1292 loop_sysfs_init(lo);
1293
1294 size = get_loop_size(lo, file);
1295 loop_set_size(lo, size);
1296
1297
1298 wmb();
1299
1300 lo->lo_state = Lo_bound;
1301 if (part_shift)
1302 lo->lo_flags |= LO_FLAGS_PARTSCAN;
1303 partscan = lo->lo_flags & LO_FLAGS_PARTSCAN;
1304 if (partscan)
1305 lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN;
1306
1307
1308
1309
1310 bdgrab(bdev);
1311 loop_global_unlock(lo, is_loop);
1312 if (partscan)
1313 loop_reread_partitions(lo);
1314 if (!(mode & FMODE_EXCL))
1315 bd_abort_claiming(bdev, loop_configure);
1316 return 0;
1317
1318out_unlock:
1319 loop_global_unlock(lo, is_loop);
1320out_bdev:
1321 if (!(mode & FMODE_EXCL))
1322 bd_abort_claiming(bdev, loop_configure);
1323out_putf:
1324 fput(file);
1325
1326 module_put(THIS_MODULE);
1327 return error;
1328}
1329
1330static int __loop_clr_fd(struct loop_device *lo, bool release)
1331{
1332 struct file *filp = NULL;
1333 gfp_t gfp = lo->old_gfp_mask;
1334 struct block_device *bdev = lo->lo_device;
1335 int err = 0;
1336 bool partscan = false;
1337 int lo_number;
1338 struct loop_worker *pos, *worker;
1339
1340
1341
1342
1343
1344
1345 mutex_lock(&loop_validate_mutex);
1346 mutex_unlock(&loop_validate_mutex);
1347
1348
1349
1350
1351
1352 mutex_lock(&lo->lo_mutex);
1353 if (WARN_ON_ONCE(lo->lo_state != Lo_rundown)) {
1354 err = -ENXIO;
1355 goto out_unlock;
1356 }
1357
1358 filp = lo->lo_backing_file;
1359 if (filp == NULL) {
1360 err = -EINVAL;
1361 goto out_unlock;
1362 }
1363
1364 if (test_bit(QUEUE_FLAG_WC, &lo->lo_queue->queue_flags))
1365 blk_queue_write_cache(lo->lo_queue, false, false);
1366
1367
1368 blk_mq_freeze_queue(lo->lo_queue);
1369
1370 destroy_workqueue(lo->workqueue);
1371 spin_lock_irq(&lo->lo_work_lock);
1372 list_for_each_entry_safe(worker, pos, &lo->idle_worker_list,
1373 idle_list) {
1374 list_del(&worker->idle_list);
1375 rb_erase(&worker->rb_node, &lo->worker_tree);
1376 css_put(worker->blkcg_css);
1377 kfree(worker);
1378 }
1379 spin_unlock_irq(&lo->lo_work_lock);
1380 del_timer_sync(&lo->timer);
1381
1382 spin_lock_irq(&lo->lo_lock);
1383 lo->lo_backing_file = NULL;
1384 spin_unlock_irq(&lo->lo_lock);
1385
1386 loop_release_xfer(lo);
1387 lo->transfer = NULL;
1388 lo->ioctl = NULL;
1389 lo->lo_device = NULL;
1390 lo->lo_encryption = NULL;
1391 lo->lo_offset = 0;
1392 lo->lo_sizelimit = 0;
1393 lo->lo_encrypt_key_size = 0;
1394 memset(lo->lo_encrypt_key, 0, LO_KEY_SIZE);
1395 memset(lo->lo_crypt_name, 0, LO_NAME_SIZE);
1396 memset(lo->lo_file_name, 0, LO_NAME_SIZE);
1397 blk_queue_logical_block_size(lo->lo_queue, 512);
1398 blk_queue_physical_block_size(lo->lo_queue, 512);
1399 blk_queue_io_min(lo->lo_queue, 512);
1400 if (bdev) {
1401 bdput(bdev);
1402 invalidate_bdev(bdev);
1403 bdev->bd_inode->i_mapping->wb_err = 0;
1404 }
1405 set_capacity(lo->lo_disk, 0);
1406 loop_sysfs_exit(lo);
1407 if (bdev) {
1408
1409 kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE);
1410 }
1411 mapping_set_gfp_mask(filp->f_mapping, gfp);
1412
1413 module_put(THIS_MODULE);
1414 blk_mq_unfreeze_queue(lo->lo_queue);
1415
1416 partscan = lo->lo_flags & LO_FLAGS_PARTSCAN && bdev;
1417 lo_number = lo->lo_number;
1418out_unlock:
1419 mutex_unlock(&lo->lo_mutex);
1420 if (partscan) {
1421
1422
1423
1424
1425
1426
1427
1428
1429 if (!release)
1430 mutex_lock(&lo->lo_disk->open_mutex);
1431 err = bdev_disk_changed(lo->lo_disk, false);
1432 if (!release)
1433 mutex_unlock(&lo->lo_disk->open_mutex);
1434 if (err)
1435 pr_warn("%s: partition scan of loop%d failed (rc=%d)\n",
1436 __func__, lo_number, err);
1437
1438 err = 0;
1439 }
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450 mutex_lock(&lo->lo_mutex);
1451 lo->lo_flags = 0;
1452 if (!part_shift)
1453 lo->lo_disk->flags |= GENHD_FL_NO_PART_SCAN;
1454 lo->lo_state = Lo_unbound;
1455 mutex_unlock(&lo->lo_mutex);
1456
1457
1458
1459
1460
1461
1462 if (filp)
1463 fput(filp);
1464 return err;
1465}
1466
1467static int loop_clr_fd(struct loop_device *lo)
1468{
1469 int err;
1470
1471 err = mutex_lock_killable(&lo->lo_mutex);
1472 if (err)
1473 return err;
1474 if (lo->lo_state != Lo_bound) {
1475 mutex_unlock(&lo->lo_mutex);
1476 return -ENXIO;
1477 }
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488 if (atomic_read(&lo->lo_refcnt) > 1) {
1489 lo->lo_flags |= LO_FLAGS_AUTOCLEAR;
1490 mutex_unlock(&lo->lo_mutex);
1491 return 0;
1492 }
1493 lo->lo_state = Lo_rundown;
1494 mutex_unlock(&lo->lo_mutex);
1495
1496 return __loop_clr_fd(lo, false);
1497}
1498
1499static int
1500loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
1501{
1502 int err;
1503 kuid_t uid = current_uid();
1504 int prev_lo_flags;
1505 bool partscan = false;
1506 bool size_changed = false;
1507
1508 err = mutex_lock_killable(&lo->lo_mutex);
1509 if (err)
1510 return err;
1511 if (lo->lo_encrypt_key_size &&
1512 !uid_eq(lo->lo_key_owner, uid) &&
1513 !capable(CAP_SYS_ADMIN)) {
1514 err = -EPERM;
1515 goto out_unlock;
1516 }
1517 if (lo->lo_state != Lo_bound) {
1518 err = -ENXIO;
1519 goto out_unlock;
1520 }
1521
1522 if (lo->lo_offset != info->lo_offset ||
1523 lo->lo_sizelimit != info->lo_sizelimit) {
1524 size_changed = true;
1525 sync_blockdev(lo->lo_device);
1526 invalidate_bdev(lo->lo_device);
1527 }
1528
1529
1530 blk_mq_freeze_queue(lo->lo_queue);
1531
1532 if (size_changed && lo->lo_device->bd_inode->i_mapping->nrpages) {
1533
1534 err = -EAGAIN;
1535 pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n",
1536 __func__, lo->lo_number, lo->lo_file_name,
1537 lo->lo_device->bd_inode->i_mapping->nrpages);
1538 goto out_unfreeze;
1539 }
1540
1541 prev_lo_flags = lo->lo_flags;
1542
1543 err = loop_set_status_from_info(lo, info);
1544 if (err)
1545 goto out_unfreeze;
1546
1547
1548 lo->lo_flags &= LOOP_SET_STATUS_SETTABLE_FLAGS;
1549
1550 lo->lo_flags |= prev_lo_flags & ~LOOP_SET_STATUS_SETTABLE_FLAGS;
1551
1552 lo->lo_flags |= prev_lo_flags & ~LOOP_SET_STATUS_CLEARABLE_FLAGS;
1553
1554 if (size_changed) {
1555 loff_t new_size = get_size(lo->lo_offset, lo->lo_sizelimit,
1556 lo->lo_backing_file);
1557 loop_set_size(lo, new_size);
1558 }
1559
1560 loop_config_discard(lo);
1561
1562
1563 __loop_update_dio(lo, lo->use_dio);
1564
1565out_unfreeze:
1566 blk_mq_unfreeze_queue(lo->lo_queue);
1567
1568 if (!err && (lo->lo_flags & LO_FLAGS_PARTSCAN) &&
1569 !(prev_lo_flags & LO_FLAGS_PARTSCAN)) {
1570 lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN;
1571 partscan = true;
1572 }
1573out_unlock:
1574 mutex_unlock(&lo->lo_mutex);
1575 if (partscan)
1576 loop_reread_partitions(lo);
1577
1578 return err;
1579}
1580
1581static int
1582loop_get_status(struct loop_device *lo, struct loop_info64 *info)
1583{
1584 struct path path;
1585 struct kstat stat;
1586 int ret;
1587
1588 ret = mutex_lock_killable(&lo->lo_mutex);
1589 if (ret)
1590 return ret;
1591 if (lo->lo_state != Lo_bound) {
1592 mutex_unlock(&lo->lo_mutex);
1593 return -ENXIO;
1594 }
1595
1596 memset(info, 0, sizeof(*info));
1597 info->lo_number = lo->lo_number;
1598 info->lo_offset = lo->lo_offset;
1599 info->lo_sizelimit = lo->lo_sizelimit;
1600 info->lo_flags = lo->lo_flags;
1601 memcpy(info->lo_file_name, lo->lo_file_name, LO_NAME_SIZE);
1602 memcpy(info->lo_crypt_name, lo->lo_crypt_name, LO_NAME_SIZE);
1603 info->lo_encrypt_type =
1604 lo->lo_encryption ? lo->lo_encryption->number : 0;
1605 if (lo->lo_encrypt_key_size && capable(CAP_SYS_ADMIN)) {
1606 info->lo_encrypt_key_size = lo->lo_encrypt_key_size;
1607 memcpy(info->lo_encrypt_key, lo->lo_encrypt_key,
1608 lo->lo_encrypt_key_size);
1609 }
1610
1611
1612 path = lo->lo_backing_file->f_path;
1613 path_get(&path);
1614 mutex_unlock(&lo->lo_mutex);
1615 ret = vfs_getattr(&path, &stat, STATX_INO, AT_STATX_SYNC_AS_STAT);
1616 if (!ret) {
1617 info->lo_device = huge_encode_dev(stat.dev);
1618 info->lo_inode = stat.ino;
1619 info->lo_rdevice = huge_encode_dev(stat.rdev);
1620 }
1621 path_put(&path);
1622 return ret;
1623}
1624
1625static void
1626loop_info64_from_old(const struct loop_info *info, struct loop_info64 *info64)
1627{
1628 memset(info64, 0, sizeof(*info64));
1629 info64->lo_number = info->lo_number;
1630 info64->lo_device = info->lo_device;
1631 info64->lo_inode = info->lo_inode;
1632 info64->lo_rdevice = info->lo_rdevice;
1633 info64->lo_offset = info->lo_offset;
1634 info64->lo_sizelimit = 0;
1635 info64->lo_encrypt_type = info->lo_encrypt_type;
1636 info64->lo_encrypt_key_size = info->lo_encrypt_key_size;
1637 info64->lo_flags = info->lo_flags;
1638 info64->lo_init[0] = info->lo_init[0];
1639 info64->lo_init[1] = info->lo_init[1];
1640 if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI)
1641 memcpy(info64->lo_crypt_name, info->lo_name, LO_NAME_SIZE);
1642 else
1643 memcpy(info64->lo_file_name, info->lo_name, LO_NAME_SIZE);
1644 memcpy(info64->lo_encrypt_key, info->lo_encrypt_key, LO_KEY_SIZE);
1645}
1646
1647static int
1648loop_info64_to_old(const struct loop_info64 *info64, struct loop_info *info)
1649{
1650 memset(info, 0, sizeof(*info));
1651 info->lo_number = info64->lo_number;
1652 info->lo_device = info64->lo_device;
1653 info->lo_inode = info64->lo_inode;
1654 info->lo_rdevice = info64->lo_rdevice;
1655 info->lo_offset = info64->lo_offset;
1656 info->lo_encrypt_type = info64->lo_encrypt_type;
1657 info->lo_encrypt_key_size = info64->lo_encrypt_key_size;
1658 info->lo_flags = info64->lo_flags;
1659 info->lo_init[0] = info64->lo_init[0];
1660 info->lo_init[1] = info64->lo_init[1];
1661 if (info->lo_encrypt_type == LO_CRYPT_CRYPTOAPI)
1662 memcpy(info->lo_name, info64->lo_crypt_name, LO_NAME_SIZE);
1663 else
1664 memcpy(info->lo_name, info64->lo_file_name, LO_NAME_SIZE);
1665 memcpy(info->lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE);
1666
1667
1668 if (info->lo_device != info64->lo_device ||
1669 info->lo_rdevice != info64->lo_rdevice ||
1670 info->lo_inode != info64->lo_inode ||
1671 info->lo_offset != info64->lo_offset)
1672 return -EOVERFLOW;
1673
1674 return 0;
1675}
1676
1677static int
1678loop_set_status_old(struct loop_device *lo, const struct loop_info __user *arg)
1679{
1680 struct loop_info info;
1681 struct loop_info64 info64;
1682
1683 if (copy_from_user(&info, arg, sizeof (struct loop_info)))
1684 return -EFAULT;
1685 loop_info64_from_old(&info, &info64);
1686 return loop_set_status(lo, &info64);
1687}
1688
1689static int
1690loop_set_status64(struct loop_device *lo, const struct loop_info64 __user *arg)
1691{
1692 struct loop_info64 info64;
1693
1694 if (copy_from_user(&info64, arg, sizeof (struct loop_info64)))
1695 return -EFAULT;
1696 return loop_set_status(lo, &info64);
1697}
1698
1699static int
1700loop_get_status_old(struct loop_device *lo, struct loop_info __user *arg) {
1701 struct loop_info info;
1702 struct loop_info64 info64;
1703 int err;
1704
1705 if (!arg)
1706 return -EINVAL;
1707 err = loop_get_status(lo, &info64);
1708 if (!err)
1709 err = loop_info64_to_old(&info64, &info);
1710 if (!err && copy_to_user(arg, &info, sizeof(info)))
1711 err = -EFAULT;
1712
1713 return err;
1714}
1715
1716static int
1717loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) {
1718 struct loop_info64 info64;
1719 int err;
1720
1721 if (!arg)
1722 return -EINVAL;
1723 err = loop_get_status(lo, &info64);
1724 if (!err && copy_to_user(arg, &info64, sizeof(info64)))
1725 err = -EFAULT;
1726
1727 return err;
1728}
1729
1730static int loop_set_capacity(struct loop_device *lo)
1731{
1732 loff_t size;
1733
1734 if (unlikely(lo->lo_state != Lo_bound))
1735 return -ENXIO;
1736
1737 size = get_loop_size(lo, lo->lo_backing_file);
1738 loop_set_size(lo, size);
1739
1740 return 0;
1741}
1742
1743static int loop_set_dio(struct loop_device *lo, unsigned long arg)
1744{
1745 int error = -ENXIO;
1746 if (lo->lo_state != Lo_bound)
1747 goto out;
1748
1749 __loop_update_dio(lo, !!arg);
1750 if (lo->use_dio == !!arg)
1751 return 0;
1752 error = -EINVAL;
1753 out:
1754 return error;
1755}
1756
1757static int loop_set_block_size(struct loop_device *lo, unsigned long arg)
1758{
1759 int err = 0;
1760
1761 if (lo->lo_state != Lo_bound)
1762 return -ENXIO;
1763
1764 err = loop_validate_block_size(arg);
1765 if (err)
1766 return err;
1767
1768 if (lo->lo_queue->limits.logical_block_size == arg)
1769 return 0;
1770
1771 sync_blockdev(lo->lo_device);
1772 invalidate_bdev(lo->lo_device);
1773
1774 blk_mq_freeze_queue(lo->lo_queue);
1775
1776
1777 if (lo->lo_device->bd_inode->i_mapping->nrpages) {
1778 err = -EAGAIN;
1779 pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n",
1780 __func__, lo->lo_number, lo->lo_file_name,
1781 lo->lo_device->bd_inode->i_mapping->nrpages);
1782 goto out_unfreeze;
1783 }
1784
1785 blk_queue_logical_block_size(lo->lo_queue, arg);
1786 blk_queue_physical_block_size(lo->lo_queue, arg);
1787 blk_queue_io_min(lo->lo_queue, arg);
1788 loop_update_dio(lo);
1789out_unfreeze:
1790 blk_mq_unfreeze_queue(lo->lo_queue);
1791
1792 return err;
1793}
1794
1795static int lo_simple_ioctl(struct loop_device *lo, unsigned int cmd,
1796 unsigned long arg)
1797{
1798 int err;
1799
1800 err = mutex_lock_killable(&lo->lo_mutex);
1801 if (err)
1802 return err;
1803 switch (cmd) {
1804 case LOOP_SET_CAPACITY:
1805 err = loop_set_capacity(lo);
1806 break;
1807 case LOOP_SET_DIRECT_IO:
1808 err = loop_set_dio(lo, arg);
1809 break;
1810 case LOOP_SET_BLOCK_SIZE:
1811 err = loop_set_block_size(lo, arg);
1812 break;
1813 default:
1814 err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL;
1815 }
1816 mutex_unlock(&lo->lo_mutex);
1817 return err;
1818}
1819
1820static int lo_ioctl(struct block_device *bdev, fmode_t mode,
1821 unsigned int cmd, unsigned long arg)
1822{
1823 struct loop_device *lo = bdev->bd_disk->private_data;
1824 void __user *argp = (void __user *) arg;
1825 int err;
1826
1827 switch (cmd) {
1828 case LOOP_SET_FD: {
1829
1830
1831
1832
1833
1834 struct loop_config config;
1835
1836 memset(&config, 0, sizeof(config));
1837 config.fd = arg;
1838
1839 return loop_configure(lo, mode, bdev, &config);
1840 }
1841 case LOOP_CONFIGURE: {
1842 struct loop_config config;
1843
1844 if (copy_from_user(&config, argp, sizeof(config)))
1845 return -EFAULT;
1846
1847 return loop_configure(lo, mode, bdev, &config);
1848 }
1849 case LOOP_CHANGE_FD:
1850 return loop_change_fd(lo, bdev, arg);
1851 case LOOP_CLR_FD:
1852 return loop_clr_fd(lo);
1853 case LOOP_SET_STATUS:
1854 err = -EPERM;
1855 if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) {
1856 err = loop_set_status_old(lo, argp);
1857 }
1858 break;
1859 case LOOP_GET_STATUS:
1860 return loop_get_status_old(lo, argp);
1861 case LOOP_SET_STATUS64:
1862 err = -EPERM;
1863 if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) {
1864 err = loop_set_status64(lo, argp);
1865 }
1866 break;
1867 case LOOP_GET_STATUS64:
1868 return loop_get_status64(lo, argp);
1869 case LOOP_SET_CAPACITY:
1870 case LOOP_SET_DIRECT_IO:
1871 case LOOP_SET_BLOCK_SIZE:
1872 if (!(mode & FMODE_WRITE) && !capable(CAP_SYS_ADMIN))
1873 return -EPERM;
1874 fallthrough;
1875 default:
1876 err = lo_simple_ioctl(lo, cmd, arg);
1877 break;
1878 }
1879
1880 return err;
1881}
1882
1883#ifdef CONFIG_COMPAT
1884struct compat_loop_info {
1885 compat_int_t lo_number;
1886 compat_dev_t lo_device;
1887 compat_ulong_t lo_inode;
1888 compat_dev_t lo_rdevice;
1889 compat_int_t lo_offset;
1890 compat_int_t lo_encrypt_type;
1891 compat_int_t lo_encrypt_key_size;
1892 compat_int_t lo_flags;
1893 char lo_name[LO_NAME_SIZE];
1894 unsigned char lo_encrypt_key[LO_KEY_SIZE];
1895 compat_ulong_t lo_init[2];
1896 char reserved[4];
1897};
1898
1899
1900
1901
1902
1903static noinline int
1904loop_info64_from_compat(const struct compat_loop_info __user *arg,
1905 struct loop_info64 *info64)
1906{
1907 struct compat_loop_info info;
1908
1909 if (copy_from_user(&info, arg, sizeof(info)))
1910 return -EFAULT;
1911
1912 memset(info64, 0, sizeof(*info64));
1913 info64->lo_number = info.lo_number;
1914 info64->lo_device = info.lo_device;
1915 info64->lo_inode = info.lo_inode;
1916 info64->lo_rdevice = info.lo_rdevice;
1917 info64->lo_offset = info.lo_offset;
1918 info64->lo_sizelimit = 0;
1919 info64->lo_encrypt_type = info.lo_encrypt_type;
1920 info64->lo_encrypt_key_size = info.lo_encrypt_key_size;
1921 info64->lo_flags = info.lo_flags;
1922 info64->lo_init[0] = info.lo_init[0];
1923 info64->lo_init[1] = info.lo_init[1];
1924 if (info.lo_encrypt_type == LO_CRYPT_CRYPTOAPI)
1925 memcpy(info64->lo_crypt_name, info.lo_name, LO_NAME_SIZE);
1926 else
1927 memcpy(info64->lo_file_name, info.lo_name, LO_NAME_SIZE);
1928 memcpy(info64->lo_encrypt_key, info.lo_encrypt_key, LO_KEY_SIZE);
1929 return 0;
1930}
1931
1932
1933
1934
1935
1936static noinline int
1937loop_info64_to_compat(const struct loop_info64 *info64,
1938 struct compat_loop_info __user *arg)
1939{
1940 struct compat_loop_info info;
1941
1942 memset(&info, 0, sizeof(info));
1943 info.lo_number = info64->lo_number;
1944 info.lo_device = info64->lo_device;
1945 info.lo_inode = info64->lo_inode;
1946 info.lo_rdevice = info64->lo_rdevice;
1947 info.lo_offset = info64->lo_offset;
1948 info.lo_encrypt_type = info64->lo_encrypt_type;
1949 info.lo_encrypt_key_size = info64->lo_encrypt_key_size;
1950 info.lo_flags = info64->lo_flags;
1951 info.lo_init[0] = info64->lo_init[0];
1952 info.lo_init[1] = info64->lo_init[1];
1953 if (info.lo_encrypt_type == LO_CRYPT_CRYPTOAPI)
1954 memcpy(info.lo_name, info64->lo_crypt_name, LO_NAME_SIZE);
1955 else
1956 memcpy(info.lo_name, info64->lo_file_name, LO_NAME_SIZE);
1957 memcpy(info.lo_encrypt_key, info64->lo_encrypt_key, LO_KEY_SIZE);
1958
1959
1960 if (info.lo_device != info64->lo_device ||
1961 info.lo_rdevice != info64->lo_rdevice ||
1962 info.lo_inode != info64->lo_inode ||
1963 info.lo_offset != info64->lo_offset ||
1964 info.lo_init[0] != info64->lo_init[0] ||
1965 info.lo_init[1] != info64->lo_init[1])
1966 return -EOVERFLOW;
1967
1968 if (copy_to_user(arg, &info, sizeof(info)))
1969 return -EFAULT;
1970 return 0;
1971}
1972
1973static int
1974loop_set_status_compat(struct loop_device *lo,
1975 const struct compat_loop_info __user *arg)
1976{
1977 struct loop_info64 info64;
1978 int ret;
1979
1980 ret = loop_info64_from_compat(arg, &info64);
1981 if (ret < 0)
1982 return ret;
1983 return loop_set_status(lo, &info64);
1984}
1985
1986static int
1987loop_get_status_compat(struct loop_device *lo,
1988 struct compat_loop_info __user *arg)
1989{
1990 struct loop_info64 info64;
1991 int err;
1992
1993 if (!arg)
1994 return -EINVAL;
1995 err = loop_get_status(lo, &info64);
1996 if (!err)
1997 err = loop_info64_to_compat(&info64, arg);
1998 return err;
1999}
2000
2001static int lo_compat_ioctl(struct block_device *bdev, fmode_t mode,
2002 unsigned int cmd, unsigned long arg)
2003{
2004 struct loop_device *lo = bdev->bd_disk->private_data;
2005 int err;
2006
2007 switch(cmd) {
2008 case LOOP_SET_STATUS:
2009 err = loop_set_status_compat(lo,
2010 (const struct compat_loop_info __user *)arg);
2011 break;
2012 case LOOP_GET_STATUS:
2013 err = loop_get_status_compat(lo,
2014 (struct compat_loop_info __user *)arg);
2015 break;
2016 case LOOP_SET_CAPACITY:
2017 case LOOP_CLR_FD:
2018 case LOOP_GET_STATUS64:
2019 case LOOP_SET_STATUS64:
2020 case LOOP_CONFIGURE:
2021 arg = (unsigned long) compat_ptr(arg);
2022 fallthrough;
2023 case LOOP_SET_FD:
2024 case LOOP_CHANGE_FD:
2025 case LOOP_SET_BLOCK_SIZE:
2026 case LOOP_SET_DIRECT_IO:
2027 err = lo_ioctl(bdev, mode, cmd, arg);
2028 break;
2029 default:
2030 err = -ENOIOCTLCMD;
2031 break;
2032 }
2033 return err;
2034}
2035#endif
2036
2037static int lo_open(struct block_device *bdev, fmode_t mode)
2038{
2039 struct loop_device *lo = bdev->bd_disk->private_data;
2040 int err;
2041
2042 err = mutex_lock_killable(&lo->lo_mutex);
2043 if (err)
2044 return err;
2045 if (lo->lo_state == Lo_deleting)
2046 err = -ENXIO;
2047 else
2048 atomic_inc(&lo->lo_refcnt);
2049 mutex_unlock(&lo->lo_mutex);
2050 return err;
2051}
2052
2053static void lo_release(struct gendisk *disk, fmode_t mode)
2054{
2055 struct loop_device *lo = disk->private_data;
2056
2057 mutex_lock(&lo->lo_mutex);
2058 if (atomic_dec_return(&lo->lo_refcnt))
2059 goto out_unlock;
2060
2061 if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) {
2062 if (lo->lo_state != Lo_bound)
2063 goto out_unlock;
2064 lo->lo_state = Lo_rundown;
2065 mutex_unlock(&lo->lo_mutex);
2066
2067
2068
2069
2070 __loop_clr_fd(lo, true);
2071 return;
2072 } else if (lo->lo_state == Lo_bound) {
2073
2074
2075
2076
2077 blk_mq_freeze_queue(lo->lo_queue);
2078 blk_mq_unfreeze_queue(lo->lo_queue);
2079 }
2080
2081out_unlock:
2082 mutex_unlock(&lo->lo_mutex);
2083}
2084
2085static const struct block_device_operations lo_fops = {
2086 .owner = THIS_MODULE,
2087 .open = lo_open,
2088 .release = lo_release,
2089 .ioctl = lo_ioctl,
2090#ifdef CONFIG_COMPAT
2091 .compat_ioctl = lo_compat_ioctl,
2092#endif
2093};
2094
2095
2096
2097
2098static int max_loop;
2099module_param(max_loop, int, 0444);
2100MODULE_PARM_DESC(max_loop, "Maximum number of loop devices");
2101module_param(max_part, int, 0444);
2102MODULE_PARM_DESC(max_part, "Maximum number of partitions per loop device");
2103MODULE_LICENSE("GPL");
2104MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR);
2105
2106int loop_register_transfer(struct loop_func_table *funcs)
2107{
2108 unsigned int n = funcs->number;
2109
2110 if (n >= MAX_LO_CRYPT || xfer_funcs[n])
2111 return -EINVAL;
2112 xfer_funcs[n] = funcs;
2113 return 0;
2114}
2115
2116static int unregister_transfer_cb(int id, void *ptr, void *data)
2117{
2118 struct loop_device *lo = ptr;
2119 struct loop_func_table *xfer = data;
2120
2121 mutex_lock(&lo->lo_mutex);
2122 if (lo->lo_encryption == xfer)
2123 loop_release_xfer(lo);
2124 mutex_unlock(&lo->lo_mutex);
2125 return 0;
2126}
2127
2128int loop_unregister_transfer(int number)
2129{
2130 unsigned int n = number;
2131 struct loop_func_table *xfer;
2132
2133 if (n == 0 || n >= MAX_LO_CRYPT || (xfer = xfer_funcs[n]) == NULL)
2134 return -EINVAL;
2135
2136 xfer_funcs[n] = NULL;
2137 idr_for_each(&loop_index_idr, &unregister_transfer_cb, xfer);
2138 return 0;
2139}
2140
2141EXPORT_SYMBOL(loop_register_transfer);
2142EXPORT_SYMBOL(loop_unregister_transfer);
2143
2144static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx,
2145 const struct blk_mq_queue_data *bd)
2146{
2147 struct request *rq = bd->rq;
2148 struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq);
2149 struct loop_device *lo = rq->q->queuedata;
2150
2151 blk_mq_start_request(rq);
2152
2153 if (lo->lo_state != Lo_bound)
2154 return BLK_STS_IOERR;
2155
2156 switch (req_op(rq)) {
2157 case REQ_OP_FLUSH:
2158 case REQ_OP_DISCARD:
2159 case REQ_OP_WRITE_ZEROES:
2160 cmd->use_aio = false;
2161 break;
2162 default:
2163 cmd->use_aio = lo->use_dio;
2164 break;
2165 }
2166
2167
2168 cmd->blkcg_css = NULL;
2169 cmd->memcg_css = NULL;
2170#ifdef CONFIG_BLK_CGROUP
2171 if (rq->bio && rq->bio->bi_blkg) {
2172 cmd->blkcg_css = &bio_blkcg(rq->bio)->css;
2173#ifdef CONFIG_MEMCG
2174 cmd->memcg_css =
2175 cgroup_get_e_css(cmd->blkcg_css->cgroup,
2176 &memory_cgrp_subsys);
2177#endif
2178 }
2179#endif
2180 loop_queue_work(lo, cmd);
2181
2182 return BLK_STS_OK;
2183}
2184
2185static void loop_handle_cmd(struct loop_cmd *cmd)
2186{
2187 struct request *rq = blk_mq_rq_from_pdu(cmd);
2188 const bool write = op_is_write(req_op(rq));
2189 struct loop_device *lo = rq->q->queuedata;
2190 int ret = 0;
2191 struct mem_cgroup *old_memcg = NULL;
2192
2193 if (write && (lo->lo_flags & LO_FLAGS_READ_ONLY)) {
2194 ret = -EIO;
2195 goto failed;
2196 }
2197
2198 if (cmd->blkcg_css)
2199 kthread_associate_blkcg(cmd->blkcg_css);
2200 if (cmd->memcg_css)
2201 old_memcg = set_active_memcg(
2202 mem_cgroup_from_css(cmd->memcg_css));
2203
2204 ret = do_req_filebacked(lo, rq);
2205
2206 if (cmd->blkcg_css)
2207 kthread_associate_blkcg(NULL);
2208
2209 if (cmd->memcg_css) {
2210 set_active_memcg(old_memcg);
2211 css_put(cmd->memcg_css);
2212 }
2213 failed:
2214
2215 if (!cmd->use_aio || ret) {
2216 if (ret == -EOPNOTSUPP)
2217 cmd->ret = ret;
2218 else
2219 cmd->ret = ret ? -EIO : 0;
2220 if (likely(!blk_should_fake_timeout(rq->q)))
2221 blk_mq_complete_request(rq);
2222 }
2223}
2224
2225static void loop_set_timer(struct loop_device *lo)
2226{
2227 timer_reduce(&lo->timer, jiffies + LOOP_IDLE_WORKER_TIMEOUT);
2228}
2229
2230static void loop_process_work(struct loop_worker *worker,
2231 struct list_head *cmd_list, struct loop_device *lo)
2232{
2233 int orig_flags = current->flags;
2234 struct loop_cmd *cmd;
2235
2236 current->flags |= PF_LOCAL_THROTTLE | PF_MEMALLOC_NOIO;
2237 spin_lock_irq(&lo->lo_work_lock);
2238 while (!list_empty(cmd_list)) {
2239 cmd = container_of(
2240 cmd_list->next, struct loop_cmd, list_entry);
2241 list_del(cmd_list->next);
2242 spin_unlock_irq(&lo->lo_work_lock);
2243
2244 loop_handle_cmd(cmd);
2245 cond_resched();
2246
2247 spin_lock_irq(&lo->lo_work_lock);
2248 }
2249
2250
2251
2252
2253
2254
2255 if (worker && !work_pending(&worker->work)) {
2256 worker->last_ran_at = jiffies;
2257 list_add_tail(&worker->idle_list, &lo->idle_worker_list);
2258 loop_set_timer(lo);
2259 }
2260 spin_unlock_irq(&lo->lo_work_lock);
2261 current->flags = orig_flags;
2262}
2263
2264static void loop_workfn(struct work_struct *work)
2265{
2266 struct loop_worker *worker =
2267 container_of(work, struct loop_worker, work);
2268 loop_process_work(worker, &worker->cmd_list, worker->lo);
2269}
2270
2271static void loop_rootcg_workfn(struct work_struct *work)
2272{
2273 struct loop_device *lo =
2274 container_of(work, struct loop_device, rootcg_work);
2275 loop_process_work(NULL, &lo->rootcg_cmd_list, lo);
2276}
2277
2278static void loop_free_idle_workers(struct timer_list *timer)
2279{
2280 struct loop_device *lo = container_of(timer, struct loop_device, timer);
2281 struct loop_worker *pos, *worker;
2282
2283 spin_lock_irq(&lo->lo_work_lock);
2284 list_for_each_entry_safe(worker, pos, &lo->idle_worker_list,
2285 idle_list) {
2286 if (time_is_after_jiffies(worker->last_ran_at +
2287 LOOP_IDLE_WORKER_TIMEOUT))
2288 break;
2289 list_del(&worker->idle_list);
2290 rb_erase(&worker->rb_node, &lo->worker_tree);
2291 css_put(worker->blkcg_css);
2292 kfree(worker);
2293 }
2294 if (!list_empty(&lo->idle_worker_list))
2295 loop_set_timer(lo);
2296 spin_unlock_irq(&lo->lo_work_lock);
2297}
2298
2299static const struct blk_mq_ops loop_mq_ops = {
2300 .queue_rq = loop_queue_rq,
2301 .complete = lo_complete_rq,
2302};
2303
2304static int loop_add(int i)
2305{
2306 struct loop_device *lo;
2307 struct gendisk *disk;
2308 int err;
2309
2310 err = -ENOMEM;
2311 lo = kzalloc(sizeof(*lo), GFP_KERNEL);
2312 if (!lo)
2313 goto out;
2314 lo->lo_state = Lo_unbound;
2315
2316 err = mutex_lock_killable(&loop_ctl_mutex);
2317 if (err)
2318 goto out_free_dev;
2319
2320
2321 if (i >= 0) {
2322 err = idr_alloc(&loop_index_idr, lo, i, i + 1, GFP_KERNEL);
2323 if (err == -ENOSPC)
2324 err = -EEXIST;
2325 } else {
2326 err = idr_alloc(&loop_index_idr, lo, 0, 0, GFP_KERNEL);
2327 }
2328 if (err < 0)
2329 goto out_unlock;
2330 i = err;
2331
2332 err = -ENOMEM;
2333 lo->tag_set.ops = &loop_mq_ops;
2334 lo->tag_set.nr_hw_queues = 1;
2335 lo->tag_set.queue_depth = 128;
2336 lo->tag_set.numa_node = NUMA_NO_NODE;
2337 lo->tag_set.cmd_size = sizeof(struct loop_cmd);
2338 lo->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_STACKING;
2339 lo->tag_set.driver_data = lo;
2340
2341 err = blk_mq_alloc_tag_set(&lo->tag_set);
2342 if (err)
2343 goto out_free_idr;
2344
2345 disk = lo->lo_disk = blk_mq_alloc_disk(&lo->tag_set, lo);
2346 if (IS_ERR(disk)) {
2347 err = PTR_ERR(disk);
2348 goto out_cleanup_tags;
2349 }
2350 lo->lo_queue = lo->lo_disk->queue;
2351
2352 blk_queue_max_hw_sectors(lo->lo_queue, BLK_DEF_MAX_SECTORS);
2353
2354
2355
2356
2357
2358
2359
2360 blk_queue_flag_set(QUEUE_FLAG_NOMERGES, lo->lo_queue);
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380 if (!part_shift)
2381 disk->flags |= GENHD_FL_NO_PART_SCAN;
2382 disk->flags |= GENHD_FL_EXT_DEVT;
2383 atomic_set(&lo->lo_refcnt, 0);
2384 mutex_init(&lo->lo_mutex);
2385 lo->lo_number = i;
2386 spin_lock_init(&lo->lo_lock);
2387 spin_lock_init(&lo->lo_work_lock);
2388 disk->major = LOOP_MAJOR;
2389 disk->first_minor = i << part_shift;
2390 disk->minors = 1 << part_shift;
2391 disk->fops = &lo_fops;
2392 disk->private_data = lo;
2393 disk->queue = lo->lo_queue;
2394 sprintf(disk->disk_name, "loop%d", i);
2395 add_disk(disk);
2396 mutex_unlock(&loop_ctl_mutex);
2397 return i;
2398
2399out_cleanup_tags:
2400 blk_mq_free_tag_set(&lo->tag_set);
2401out_free_idr:
2402 idr_remove(&loop_index_idr, i);
2403out_unlock:
2404 mutex_unlock(&loop_ctl_mutex);
2405out_free_dev:
2406 kfree(lo);
2407out:
2408 return err;
2409}
2410
2411static void loop_remove(struct loop_device *lo)
2412{
2413 del_gendisk(lo->lo_disk);
2414 blk_cleanup_disk(lo->lo_disk);
2415 blk_mq_free_tag_set(&lo->tag_set);
2416 mutex_destroy(&lo->lo_mutex);
2417 kfree(lo);
2418}
2419
2420static void loop_probe(dev_t dev)
2421{
2422 int idx = MINOR(dev) >> part_shift;
2423
2424 if (max_loop && idx >= max_loop)
2425 return;
2426 loop_add(idx);
2427}
2428
2429static int loop_control_remove(int idx)
2430{
2431 struct loop_device *lo;
2432 int ret;
2433
2434 if (idx < 0) {
2435 pr_warn("deleting an unspecified loop device is not supported.\n");
2436 return -EINVAL;
2437 }
2438
2439 ret = mutex_lock_killable(&loop_ctl_mutex);
2440 if (ret)
2441 return ret;
2442
2443 lo = idr_find(&loop_index_idr, idx);
2444 if (!lo) {
2445 ret = -ENODEV;
2446 goto out_unlock_ctrl;
2447 }
2448
2449 ret = mutex_lock_killable(&lo->lo_mutex);
2450 if (ret)
2451 goto out_unlock_ctrl;
2452 if (lo->lo_state != Lo_unbound ||
2453 atomic_read(&lo->lo_refcnt) > 0) {
2454 mutex_unlock(&lo->lo_mutex);
2455 ret = -EBUSY;
2456 goto out_unlock_ctrl;
2457 }
2458 lo->lo_state = Lo_deleting;
2459 mutex_unlock(&lo->lo_mutex);
2460
2461 idr_remove(&loop_index_idr, lo->lo_number);
2462 loop_remove(lo);
2463out_unlock_ctrl:
2464 mutex_unlock(&loop_ctl_mutex);
2465 return ret;
2466}
2467
2468static int loop_control_get_free(int idx)
2469{
2470 struct loop_device *lo;
2471 int id, ret;
2472
2473 ret = mutex_lock_killable(&loop_ctl_mutex);
2474 if (ret)
2475 return ret;
2476 idr_for_each_entry(&loop_index_idr, lo, id) {
2477 if (lo->lo_state == Lo_unbound)
2478 goto found;
2479 }
2480 mutex_unlock(&loop_ctl_mutex);
2481 return loop_add(-1);
2482found:
2483 mutex_unlock(&loop_ctl_mutex);
2484 return id;
2485}
2486
2487static long loop_control_ioctl(struct file *file, unsigned int cmd,
2488 unsigned long parm)
2489{
2490 switch (cmd) {
2491 case LOOP_CTL_ADD:
2492 return loop_add(parm);
2493 case LOOP_CTL_REMOVE:
2494 return loop_control_remove(parm);
2495 case LOOP_CTL_GET_FREE:
2496 return loop_control_get_free(parm);
2497 default:
2498 return -ENOSYS;
2499 }
2500}
2501
2502static const struct file_operations loop_ctl_fops = {
2503 .open = nonseekable_open,
2504 .unlocked_ioctl = loop_control_ioctl,
2505 .compat_ioctl = loop_control_ioctl,
2506 .owner = THIS_MODULE,
2507 .llseek = noop_llseek,
2508};
2509
2510static struct miscdevice loop_misc = {
2511 .minor = LOOP_CTRL_MINOR,
2512 .name = "loop-control",
2513 .fops = &loop_ctl_fops,
2514};
2515
2516MODULE_ALIAS_MISCDEV(LOOP_CTRL_MINOR);
2517MODULE_ALIAS("devname:loop-control");
2518
2519static int __init loop_init(void)
2520{
2521 int i, nr;
2522 int err;
2523
2524 part_shift = 0;
2525 if (max_part > 0) {
2526 part_shift = fls(max_part);
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536 max_part = (1UL << part_shift) - 1;
2537 }
2538
2539 if ((1UL << part_shift) > DISK_MAX_PARTS) {
2540 err = -EINVAL;
2541 goto err_out;
2542 }
2543
2544 if (max_loop > 1UL << (MINORBITS - part_shift)) {
2545 err = -EINVAL;
2546 goto err_out;
2547 }
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557 if (max_loop)
2558 nr = max_loop;
2559 else
2560 nr = CONFIG_BLK_DEV_LOOP_MIN_COUNT;
2561
2562 err = misc_register(&loop_misc);
2563 if (err < 0)
2564 goto err_out;
2565
2566
2567 if (__register_blkdev(LOOP_MAJOR, "loop", loop_probe)) {
2568 err = -EIO;
2569 goto misc_out;
2570 }
2571
2572
2573 for (i = 0; i < nr; i++)
2574 loop_add(i);
2575
2576 printk(KERN_INFO "loop: module loaded\n");
2577 return 0;
2578
2579misc_out:
2580 misc_deregister(&loop_misc);
2581err_out:
2582 return err;
2583}
2584
2585static void __exit loop_exit(void)
2586{
2587 struct loop_device *lo;
2588 int id;
2589
2590 unregister_blkdev(LOOP_MAJOR, "loop");
2591 misc_deregister(&loop_misc);
2592
2593 mutex_lock(&loop_ctl_mutex);
2594 idr_for_each_entry(&loop_index_idr, lo, id)
2595 loop_remove(lo);
2596 mutex_unlock(&loop_ctl_mutex);
2597
2598 idr_destroy(&loop_index_idr);
2599}
2600
2601module_init(loop_init);
2602module_exit(loop_exit);
2603
2604#ifndef MODULE
2605static int __init max_loop_setup(char *str)
2606{
2607 max_loop = simple_strtol(str, NULL, 0);
2608 return 1;
2609}
2610
2611__setup("max_loop=", max_loop_setup);
2612#endif
2613