1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2025, Christoph Hellwig.
4 * Copyright (c) 2025, Western Digital Corporation or its affiliates.
5 *
6 * Zoned Loop Device driver - exports a zoned block device using one file per
7 * zone as backing storage.
8 */
9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10
11#include <linux/module.h>
12#include <linux/blk-mq.h>
13#include <linux/blkzoned.h>
14#include <linux/pagemap.h>
15#include <linux/miscdevice.h>
16#include <linux/falloc.h>
17#include <linux/mutex.h>
18#include <linux/parser.h>
19#include <linux/seq_file.h>
20
21/*
22 * Options for adding (and removing) a device.
23 */
24enum {
25 ZLOOP_OPT_ERR = 0,
26 ZLOOP_OPT_ID = (1 << 0),
27 ZLOOP_OPT_CAPACITY = (1 << 1),
28 ZLOOP_OPT_ZONE_SIZE = (1 << 2),
29 ZLOOP_OPT_ZONE_CAPACITY = (1 << 3),
30 ZLOOP_OPT_NR_CONV_ZONES = (1 << 4),
31 ZLOOP_OPT_BASE_DIR = (1 << 5),
32 ZLOOP_OPT_NR_QUEUES = (1 << 6),
33 ZLOOP_OPT_QUEUE_DEPTH = (1 << 7),
34 ZLOOP_OPT_BUFFERED_IO = (1 << 8),
35 ZLOOP_OPT_ZONE_APPEND = (1 << 9),
36 ZLOOP_OPT_ORDERED_ZONE_APPEND = (1 << 10),
37};
38
39static const match_table_t zloop_opt_tokens = {
40 { ZLOOP_OPT_ID, "id=%d" },
41 { ZLOOP_OPT_CAPACITY, "capacity_mb=%u" },
42 { ZLOOP_OPT_ZONE_SIZE, "zone_size_mb=%u" },
43 { ZLOOP_OPT_ZONE_CAPACITY, "zone_capacity_mb=%u" },
44 { ZLOOP_OPT_NR_CONV_ZONES, "conv_zones=%u" },
45 { ZLOOP_OPT_BASE_DIR, "base_dir=%s" },
46 { ZLOOP_OPT_NR_QUEUES, "nr_queues=%u" },
47 { ZLOOP_OPT_QUEUE_DEPTH, "queue_depth=%u" },
48 { ZLOOP_OPT_BUFFERED_IO, "buffered_io" },
49 { ZLOOP_OPT_ZONE_APPEND, "zone_append=%u" },
50 { ZLOOP_OPT_ORDERED_ZONE_APPEND, "ordered_zone_append" },
51 { ZLOOP_OPT_ERR, NULL }
52};
53
54/* Default values for the "add" operation. */
55#define ZLOOP_DEF_ID -1
56#define ZLOOP_DEF_ZONE_SIZE ((256ULL * SZ_1M) >> SECTOR_SHIFT)
57#define ZLOOP_DEF_NR_ZONES 64
58#define ZLOOP_DEF_NR_CONV_ZONES 8
59#define ZLOOP_DEF_BASE_DIR "/var/local/zloop"
60#define ZLOOP_DEF_NR_QUEUES 1
61#define ZLOOP_DEF_QUEUE_DEPTH 128
62#define ZLOOP_DEF_BUFFERED_IO false
63#define ZLOOP_DEF_ZONE_APPEND true
64#define ZLOOP_DEF_ORDERED_ZONE_APPEND false
65
66/* Arbitrary limit on the zone size (16GB). */
67#define ZLOOP_MAX_ZONE_SIZE_MB 16384
68
69struct zloop_options {
70 unsigned int mask;
71 int id;
72 sector_t capacity;
73 sector_t zone_size;
74 sector_t zone_capacity;
75 unsigned int nr_conv_zones;
76 char *base_dir;
77 unsigned int nr_queues;
78 unsigned int queue_depth;
79 bool buffered_io;
80 bool zone_append;
81 bool ordered_zone_append;
82};
83
84/*
85 * Device states.
86 */
87enum {
88 Zlo_creating = 0,
89 Zlo_live,
90 Zlo_deleting,
91};
92
93enum zloop_zone_flags {
94 ZLOOP_ZONE_CONV = 0,
95 ZLOOP_ZONE_SEQ_ERROR,
96};
97
98struct zloop_zone {
99 struct file *file;
100
101 unsigned long flags;
102 struct mutex lock;
103 spinlock_t wp_lock;
104 enum blk_zone_cond cond;
105 sector_t start;
106 sector_t wp;
107
108 gfp_t old_gfp_mask;
109};
110
111struct zloop_device {
112 unsigned int id;
113 unsigned int state;
114
115 struct blk_mq_tag_set tag_set;
116 struct gendisk *disk;
117
118 struct workqueue_struct *workqueue;
119 bool buffered_io;
120 bool zone_append;
121 bool ordered_zone_append;
122
123 const char *base_dir;
124 struct file *data_dir;
125
126 unsigned int zone_shift;
127 sector_t zone_size;
128 sector_t zone_capacity;
129 unsigned int nr_zones;
130 unsigned int nr_conv_zones;
131 unsigned int block_size;
132
133 struct zloop_zone zones[] __counted_by(nr_zones);
134};
135
136struct zloop_cmd {
137 struct work_struct work;
138 atomic_t ref;
139 sector_t sector;
140 sector_t nr_sectors;
141 long ret;
142 struct kiocb iocb;
143 struct bio_vec *bvec;
144};
145
146static DEFINE_IDR(zloop_index_idr);
147static DEFINE_MUTEX(zloop_ctl_mutex);
148
149static unsigned int rq_zone_no(struct request *rq)
150{
151 struct zloop_device *zlo = rq->q->queuedata;
152
153 return blk_rq_pos(rq) >> zlo->zone_shift;
154}
155
156static int zloop_update_seq_zone(struct zloop_device *zlo, unsigned int zone_no)
157{
158 struct zloop_zone *zone = &zlo->zones[zone_no];
159 struct kstat stat;
160 sector_t file_sectors;
161 unsigned long flags;
162 int ret;
163
164 lockdep_assert_held(&zone->lock);
165
166 ret = vfs_getattr(&zone->file->f_path, &stat, STATX_SIZE, 0);
167 if (ret < 0) {
168 pr_err("Failed to get zone %u file stat (err=%d)\n",
169 zone_no, ret);
170 set_bit(nr: ZLOOP_ZONE_SEQ_ERROR, addr: &zone->flags);
171 return ret;
172 }
173
174 file_sectors = stat.size >> SECTOR_SHIFT;
175 if (file_sectors > zlo->zone_capacity) {
176 pr_err("Zone %u file too large (%llu sectors > %llu)\n",
177 zone_no, file_sectors, zlo->zone_capacity);
178 return -EINVAL;
179 }
180
181 if (file_sectors & ((zlo->block_size >> SECTOR_SHIFT) - 1)) {
182 pr_err("Zone %u file size not aligned to block size %u\n",
183 zone_no, zlo->block_size);
184 return -EINVAL;
185 }
186
187 spin_lock_irqsave(&zone->wp_lock, flags);
188 if (!file_sectors) {
189 zone->cond = BLK_ZONE_COND_EMPTY;
190 zone->wp = zone->start;
191 } else if (file_sectors == zlo->zone_capacity) {
192 zone->cond = BLK_ZONE_COND_FULL;
193 zone->wp = ULLONG_MAX;
194 } else {
195 zone->cond = BLK_ZONE_COND_CLOSED;
196 zone->wp = zone->start + file_sectors;
197 }
198 spin_unlock_irqrestore(lock: &zone->wp_lock, flags);
199
200 return 0;
201}
202
203static int zloop_open_zone(struct zloop_device *zlo, unsigned int zone_no)
204{
205 struct zloop_zone *zone = &zlo->zones[zone_no];
206 int ret = 0;
207
208 if (test_bit(ZLOOP_ZONE_CONV, &zone->flags))
209 return -EIO;
210
211 mutex_lock(&zone->lock);
212
213 if (test_and_clear_bit(nr: ZLOOP_ZONE_SEQ_ERROR, addr: &zone->flags)) {
214 ret = zloop_update_seq_zone(zlo, zone_no);
215 if (ret)
216 goto unlock;
217 }
218
219 switch (zone->cond) {
220 case BLK_ZONE_COND_EXP_OPEN:
221 break;
222 case BLK_ZONE_COND_EMPTY:
223 case BLK_ZONE_COND_CLOSED:
224 case BLK_ZONE_COND_IMP_OPEN:
225 zone->cond = BLK_ZONE_COND_EXP_OPEN;
226 break;
227 case BLK_ZONE_COND_FULL:
228 default:
229 ret = -EIO;
230 break;
231 }
232
233unlock:
234 mutex_unlock(lock: &zone->lock);
235
236 return ret;
237}
238
239static int zloop_close_zone(struct zloop_device *zlo, unsigned int zone_no)
240{
241 struct zloop_zone *zone = &zlo->zones[zone_no];
242 unsigned long flags;
243 int ret = 0;
244
245 if (test_bit(ZLOOP_ZONE_CONV, &zone->flags))
246 return -EIO;
247
248 mutex_lock(&zone->lock);
249
250 if (test_and_clear_bit(nr: ZLOOP_ZONE_SEQ_ERROR, addr: &zone->flags)) {
251 ret = zloop_update_seq_zone(zlo, zone_no);
252 if (ret)
253 goto unlock;
254 }
255
256 switch (zone->cond) {
257 case BLK_ZONE_COND_CLOSED:
258 break;
259 case BLK_ZONE_COND_IMP_OPEN:
260 case BLK_ZONE_COND_EXP_OPEN:
261 spin_lock_irqsave(&zone->wp_lock, flags);
262 if (zone->wp == zone->start)
263 zone->cond = BLK_ZONE_COND_EMPTY;
264 else
265 zone->cond = BLK_ZONE_COND_CLOSED;
266 spin_unlock_irqrestore(lock: &zone->wp_lock, flags);
267 break;
268 case BLK_ZONE_COND_EMPTY:
269 case BLK_ZONE_COND_FULL:
270 default:
271 ret = -EIO;
272 break;
273 }
274
275unlock:
276 mutex_unlock(lock: &zone->lock);
277
278 return ret;
279}
280
281static int zloop_reset_zone(struct zloop_device *zlo, unsigned int zone_no)
282{
283 struct zloop_zone *zone = &zlo->zones[zone_no];
284 unsigned long flags;
285 int ret = 0;
286
287 if (test_bit(ZLOOP_ZONE_CONV, &zone->flags))
288 return -EIO;
289
290 mutex_lock(&zone->lock);
291
292 if (!test_bit(ZLOOP_ZONE_SEQ_ERROR, &zone->flags) &&
293 zone->cond == BLK_ZONE_COND_EMPTY)
294 goto unlock;
295
296 if (vfs_truncate(&zone->file->f_path, 0)) {
297 set_bit(nr: ZLOOP_ZONE_SEQ_ERROR, addr: &zone->flags);
298 ret = -EIO;
299 goto unlock;
300 }
301
302 spin_lock_irqsave(&zone->wp_lock, flags);
303 zone->cond = BLK_ZONE_COND_EMPTY;
304 zone->wp = zone->start;
305 clear_bit(nr: ZLOOP_ZONE_SEQ_ERROR, addr: &zone->flags);
306 spin_unlock_irqrestore(lock: &zone->wp_lock, flags);
307
308unlock:
309 mutex_unlock(lock: &zone->lock);
310
311 return ret;
312}
313
314static int zloop_reset_all_zones(struct zloop_device *zlo)
315{
316 unsigned int i;
317 int ret;
318
319 for (i = zlo->nr_conv_zones; i < zlo->nr_zones; i++) {
320 ret = zloop_reset_zone(zlo, zone_no: i);
321 if (ret)
322 return ret;
323 }
324
325 return 0;
326}
327
328static int zloop_finish_zone(struct zloop_device *zlo, unsigned int zone_no)
329{
330 struct zloop_zone *zone = &zlo->zones[zone_no];
331 unsigned long flags;
332 int ret = 0;
333
334 if (test_bit(ZLOOP_ZONE_CONV, &zone->flags))
335 return -EIO;
336
337 mutex_lock(&zone->lock);
338
339 if (!test_bit(ZLOOP_ZONE_SEQ_ERROR, &zone->flags) &&
340 zone->cond == BLK_ZONE_COND_FULL)
341 goto unlock;
342
343 if (vfs_truncate(&zone->file->f_path, zlo->zone_size << SECTOR_SHIFT)) {
344 set_bit(nr: ZLOOP_ZONE_SEQ_ERROR, addr: &zone->flags);
345 ret = -EIO;
346 goto unlock;
347 }
348
349 spin_lock_irqsave(&zone->wp_lock, flags);
350 zone->cond = BLK_ZONE_COND_FULL;
351 zone->wp = ULLONG_MAX;
352 clear_bit(nr: ZLOOP_ZONE_SEQ_ERROR, addr: &zone->flags);
353 spin_unlock_irqrestore(lock: &zone->wp_lock, flags);
354
355 unlock:
356 mutex_unlock(lock: &zone->lock);
357
358 return ret;
359}
360
361static void zloop_put_cmd(struct zloop_cmd *cmd)
362{
363 struct request *rq = blk_mq_rq_from_pdu(pdu: cmd);
364
365 if (!atomic_dec_and_test(v: &cmd->ref))
366 return;
367 kfree(objp: cmd->bvec);
368 cmd->bvec = NULL;
369 if (likely(!blk_should_fake_timeout(rq->q)))
370 blk_mq_complete_request(rq);
371}
372
373static void zloop_rw_complete(struct kiocb *iocb, long ret)
374{
375 struct zloop_cmd *cmd = container_of(iocb, struct zloop_cmd, iocb);
376
377 cmd->ret = ret;
378 zloop_put_cmd(cmd);
379}
380
381static void zloop_rw(struct zloop_cmd *cmd)
382{
383 struct request *rq = blk_mq_rq_from_pdu(pdu: cmd);
384 struct zloop_device *zlo = rq->q->queuedata;
385 unsigned int zone_no = rq_zone_no(rq);
386 sector_t sector = blk_rq_pos(rq);
387 sector_t nr_sectors = blk_rq_sectors(rq);
388 bool is_append = req_op(req: rq) == REQ_OP_ZONE_APPEND;
389 bool is_write = req_op(req: rq) == REQ_OP_WRITE || is_append;
390 int rw = is_write ? ITER_SOURCE : ITER_DEST;
391 struct req_iterator rq_iter;
392 struct zloop_zone *zone;
393 struct iov_iter iter;
394 struct bio_vec tmp;
395 unsigned long flags;
396 sector_t zone_end;
397 unsigned int nr_bvec;
398 int ret;
399
400 atomic_set(v: &cmd->ref, i: 2);
401 cmd->sector = sector;
402 cmd->nr_sectors = nr_sectors;
403 cmd->ret = 0;
404
405 if (WARN_ON_ONCE(is_append && !zlo->zone_append)) {
406 ret = -EIO;
407 goto out;
408 }
409
410 /* We should never get an I/O beyond the device capacity. */
411 if (WARN_ON_ONCE(zone_no >= zlo->nr_zones)) {
412 ret = -EIO;
413 goto out;
414 }
415 zone = &zlo->zones[zone_no];
416 zone_end = zone->start + zlo->zone_capacity;
417
418 /*
419 * The block layer should never send requests that are not fully
420 * contained within the zone.
421 */
422 if (WARN_ON_ONCE(sector + nr_sectors > zone->start + zlo->zone_size)) {
423 ret = -EIO;
424 goto out;
425 }
426
427 if (test_and_clear_bit(nr: ZLOOP_ZONE_SEQ_ERROR, addr: &zone->flags)) {
428 mutex_lock(&zone->lock);
429 ret = zloop_update_seq_zone(zlo, zone_no);
430 mutex_unlock(lock: &zone->lock);
431 if (ret)
432 goto out;
433 }
434
435 if (!test_bit(ZLOOP_ZONE_CONV, &zone->flags) && is_write) {
436 mutex_lock(&zone->lock);
437
438 spin_lock_irqsave(&zone->wp_lock, flags);
439
440 /*
441 * Zone append operations always go at the current write
442 * pointer, but regular write operations must already be
443 * aligned to the write pointer when submitted.
444 */
445 if (is_append) {
446 /*
447 * If ordered zone append is in use, we already checked
448 * and set the target sector in zloop_queue_rq().
449 */
450 if (!zlo->ordered_zone_append) {
451 if (zone->cond == BLK_ZONE_COND_FULL ||
452 zone->wp + nr_sectors > zone_end) {
453 spin_unlock_irqrestore(lock: &zone->wp_lock,
454 flags);
455 ret = -EIO;
456 goto unlock;
457 }
458 sector = zone->wp;
459 }
460 cmd->sector = sector;
461 } else if (sector != zone->wp) {
462 spin_unlock_irqrestore(lock: &zone->wp_lock, flags);
463 pr_err("Zone %u: unaligned write: sect %llu, wp %llu\n",
464 zone_no, sector, zone->wp);
465 ret = -EIO;
466 goto unlock;
467 }
468
469 /* Implicitly open the target zone. */
470 if (zone->cond == BLK_ZONE_COND_CLOSED ||
471 zone->cond == BLK_ZONE_COND_EMPTY)
472 zone->cond = BLK_ZONE_COND_IMP_OPEN;
473
474 /*
475 * Advance the write pointer, unless ordered zone append is in
476 * use. If the write fails, the write pointer position will be
477 * corrected when the next I/O starts execution.
478 */
479 if (!is_append || !zlo->ordered_zone_append) {
480 zone->wp += nr_sectors;
481 if (zone->wp == zone_end) {
482 zone->cond = BLK_ZONE_COND_FULL;
483 zone->wp = ULLONG_MAX;
484 }
485 }
486
487 spin_unlock_irqrestore(lock: &zone->wp_lock, flags);
488 }
489
490 nr_bvec = blk_rq_nr_bvec(rq);
491
492 if (rq->bio != rq->biotail) {
493 struct bio_vec *bvec;
494
495 cmd->bvec = kmalloc_array(nr_bvec, sizeof(*cmd->bvec), GFP_NOIO);
496 if (!cmd->bvec) {
497 ret = -EIO;
498 goto unlock;
499 }
500
501 /*
502 * The bios of the request may be started from the middle of
503 * the 'bvec' because of bio splitting, so we can't directly
504 * copy bio->bi_iov_vec to new bvec. The rq_for_each_bvec
505 * API will take care of all details for us.
506 */
507 bvec = cmd->bvec;
508 rq_for_each_bvec(tmp, rq, rq_iter) {
509 *bvec = tmp;
510 bvec++;
511 }
512 iov_iter_bvec(i: &iter, direction: rw, bvec: cmd->bvec, nr_segs: nr_bvec, count: blk_rq_bytes(rq));
513 } else {
514 /*
515 * Same here, this bio may be started from the middle of the
516 * 'bvec' because of bio splitting, so offset from the bvec
517 * must be passed to iov iterator
518 */
519 iov_iter_bvec(i: &iter, direction: rw,
520 __bvec_iter_bvec(rq->bio->bi_io_vec, rq->bio->bi_iter),
521 nr_segs: nr_bvec, count: blk_rq_bytes(rq));
522 iter.iov_offset = rq->bio->bi_iter.bi_bvec_done;
523 }
524
525 cmd->iocb.ki_pos = (sector - zone->start) << SECTOR_SHIFT;
526 cmd->iocb.ki_filp = zone->file;
527 cmd->iocb.ki_complete = zloop_rw_complete;
528 if (!zlo->buffered_io)
529 cmd->iocb.ki_flags = IOCB_DIRECT;
530 cmd->iocb.ki_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, 0);
531
532 if (rw == ITER_SOURCE)
533 ret = zone->file->f_op->write_iter(&cmd->iocb, &iter);
534 else
535 ret = zone->file->f_op->read_iter(&cmd->iocb, &iter);
536unlock:
537 if (!test_bit(ZLOOP_ZONE_CONV, &zone->flags) && is_write)
538 mutex_unlock(lock: &zone->lock);
539out:
540 if (ret != -EIOCBQUEUED)
541 zloop_rw_complete(iocb: &cmd->iocb, ret);
542 zloop_put_cmd(cmd);
543}
544
545static void zloop_handle_cmd(struct zloop_cmd *cmd)
546{
547 struct request *rq = blk_mq_rq_from_pdu(pdu: cmd);
548 struct zloop_device *zlo = rq->q->queuedata;
549
550 /* We can block in this context, so ignore REQ_NOWAIT. */
551 if (rq->cmd_flags & REQ_NOWAIT)
552 rq->cmd_flags &= ~REQ_NOWAIT;
553
554 switch (req_op(req: rq)) {
555 case REQ_OP_READ:
556 case REQ_OP_WRITE:
557 case REQ_OP_ZONE_APPEND:
558 /*
559 * zloop_rw() always executes asynchronously or completes
560 * directly.
561 */
562 zloop_rw(cmd);
563 return;
564 case REQ_OP_FLUSH:
565 /*
566 * Sync the entire FS containing the zone files instead of
567 * walking all files
568 */
569 cmd->ret = sync_filesystem(file_inode(f: zlo->data_dir)->i_sb);
570 break;
571 case REQ_OP_ZONE_RESET:
572 cmd->ret = zloop_reset_zone(zlo, zone_no: rq_zone_no(rq));
573 break;
574 case REQ_OP_ZONE_RESET_ALL:
575 cmd->ret = zloop_reset_all_zones(zlo);
576 break;
577 case REQ_OP_ZONE_FINISH:
578 cmd->ret = zloop_finish_zone(zlo, zone_no: rq_zone_no(rq));
579 break;
580 case REQ_OP_ZONE_OPEN:
581 cmd->ret = zloop_open_zone(zlo, zone_no: rq_zone_no(rq));
582 break;
583 case REQ_OP_ZONE_CLOSE:
584 cmd->ret = zloop_close_zone(zlo, zone_no: rq_zone_no(rq));
585 break;
586 default:
587 WARN_ON_ONCE(1);
588 pr_err("Unsupported operation %d\n", req_op(rq));
589 cmd->ret = -EOPNOTSUPP;
590 break;
591 }
592
593 blk_mq_complete_request(rq);
594}
595
596static void zloop_cmd_workfn(struct work_struct *work)
597{
598 struct zloop_cmd *cmd = container_of(work, struct zloop_cmd, work);
599 int orig_flags = current->flags;
600
601 current->flags |= PF_LOCAL_THROTTLE | PF_MEMALLOC_NOIO;
602 zloop_handle_cmd(cmd);
603 current->flags = orig_flags;
604}
605
606static void zloop_complete_rq(struct request *rq)
607{
608 struct zloop_cmd *cmd = blk_mq_rq_to_pdu(rq);
609 struct zloop_device *zlo = rq->q->queuedata;
610 unsigned int zone_no = cmd->sector >> zlo->zone_shift;
611 struct zloop_zone *zone = &zlo->zones[zone_no];
612 blk_status_t sts = BLK_STS_OK;
613
614 switch (req_op(req: rq)) {
615 case REQ_OP_READ:
616 if (cmd->ret < 0)
617 pr_err("Zone %u: failed read sector %llu, %llu sectors\n",
618 zone_no, cmd->sector, cmd->nr_sectors);
619
620 if (cmd->ret >= 0 && cmd->ret != blk_rq_bytes(rq)) {
621 /* short read */
622 struct bio *bio;
623
624 __rq_for_each_bio(bio, rq)
625 zero_fill_bio(bio);
626 }
627 break;
628 case REQ_OP_WRITE:
629 case REQ_OP_ZONE_APPEND:
630 if (cmd->ret < 0)
631 pr_err("Zone %u: failed %swrite sector %llu, %llu sectors\n",
632 zone_no,
633 req_op(rq) == REQ_OP_WRITE ? "" : "append ",
634 cmd->sector, cmd->nr_sectors);
635
636 if (cmd->ret >= 0 && cmd->ret != blk_rq_bytes(rq)) {
637 pr_err("Zone %u: partial write %ld/%u B\n",
638 zone_no, cmd->ret, blk_rq_bytes(rq));
639 cmd->ret = -EIO;
640 }
641
642 if (cmd->ret < 0 && !test_bit(ZLOOP_ZONE_CONV, &zone->flags)) {
643 /*
644 * A write to a sequential zone file failed: mark the
645 * zone as having an error. This will be corrected and
646 * cleared when the next IO is submitted.
647 */
648 set_bit(nr: ZLOOP_ZONE_SEQ_ERROR, addr: &zone->flags);
649 break;
650 }
651 if (req_op(req: rq) == REQ_OP_ZONE_APPEND)
652 rq->__sector = cmd->sector;
653
654 break;
655 default:
656 break;
657 }
658
659 if (cmd->ret < 0)
660 sts = errno_to_blk_status(errno: cmd->ret);
661 blk_mq_end_request(rq, error: sts);
662}
663
664static bool zloop_set_zone_append_sector(struct request *rq)
665{
666 struct zloop_device *zlo = rq->q->queuedata;
667 unsigned int zone_no = rq_zone_no(rq);
668 struct zloop_zone *zone = &zlo->zones[zone_no];
669 sector_t zone_end = zone->start + zlo->zone_capacity;
670 sector_t nr_sectors = blk_rq_sectors(rq);
671 unsigned long flags;
672
673 spin_lock_irqsave(&zone->wp_lock, flags);
674
675 if (zone->cond == BLK_ZONE_COND_FULL ||
676 zone->wp + nr_sectors > zone_end) {
677 spin_unlock_irqrestore(lock: &zone->wp_lock, flags);
678 return false;
679 }
680
681 rq->__sector = zone->wp;
682 zone->wp += blk_rq_sectors(rq);
683 if (zone->wp >= zone_end) {
684 zone->cond = BLK_ZONE_COND_FULL;
685 zone->wp = ULLONG_MAX;
686 }
687
688 spin_unlock_irqrestore(lock: &zone->wp_lock, flags);
689
690 return true;
691}
692
693static blk_status_t zloop_queue_rq(struct blk_mq_hw_ctx *hctx,
694 const struct blk_mq_queue_data *bd)
695{
696 struct request *rq = bd->rq;
697 struct zloop_cmd *cmd = blk_mq_rq_to_pdu(rq);
698 struct zloop_device *zlo = rq->q->queuedata;
699
700 if (data_race(READ_ONCE(zlo->state)) == Zlo_deleting)
701 return BLK_STS_IOERR;
702
703 /*
704 * If we need to strongly order zone append operations, set the request
705 * sector to the zone write pointer location now instead of when the
706 * command work runs.
707 */
708 if (zlo->ordered_zone_append && req_op(req: rq) == REQ_OP_ZONE_APPEND) {
709 if (!zloop_set_zone_append_sector(rq))
710 return BLK_STS_IOERR;
711 }
712
713 blk_mq_start_request(rq);
714
715 INIT_WORK(&cmd->work, zloop_cmd_workfn);
716 queue_work(wq: zlo->workqueue, work: &cmd->work);
717
718 return BLK_STS_OK;
719}
720
721static const struct blk_mq_ops zloop_mq_ops = {
722 .queue_rq = zloop_queue_rq,
723 .complete = zloop_complete_rq,
724};
725
726static int zloop_open(struct gendisk *disk, blk_mode_t mode)
727{
728 struct zloop_device *zlo = disk->private_data;
729 int ret;
730
731 ret = mutex_lock_killable(&zloop_ctl_mutex);
732 if (ret)
733 return ret;
734
735 if (zlo->state != Zlo_live)
736 ret = -ENXIO;
737 mutex_unlock(lock: &zloop_ctl_mutex);
738 return ret;
739}
740
741static int zloop_report_zones(struct gendisk *disk, sector_t sector,
742 unsigned int nr_zones, struct blk_report_zones_args *args)
743{
744 struct zloop_device *zlo = disk->private_data;
745 struct blk_zone blkz = {};
746 unsigned int first, i;
747 unsigned long flags;
748 int ret;
749
750 first = disk_zone_no(disk, sector);
751 if (first >= zlo->nr_zones)
752 return 0;
753 nr_zones = min(nr_zones, zlo->nr_zones - first);
754
755 for (i = 0; i < nr_zones; i++) {
756 unsigned int zone_no = first + i;
757 struct zloop_zone *zone = &zlo->zones[zone_no];
758
759 mutex_lock(&zone->lock);
760
761 if (test_and_clear_bit(nr: ZLOOP_ZONE_SEQ_ERROR, addr: &zone->flags)) {
762 ret = zloop_update_seq_zone(zlo, zone_no);
763 if (ret) {
764 mutex_unlock(lock: &zone->lock);
765 return ret;
766 }
767 }
768
769 blkz.start = zone->start;
770 blkz.len = zlo->zone_size;
771 spin_lock_irqsave(&zone->wp_lock, flags);
772 blkz.wp = zone->wp;
773 spin_unlock_irqrestore(lock: &zone->wp_lock, flags);
774 blkz.cond = zone->cond;
775 if (test_bit(ZLOOP_ZONE_CONV, &zone->flags)) {
776 blkz.type = BLK_ZONE_TYPE_CONVENTIONAL;
777 blkz.capacity = zlo->zone_size;
778 } else {
779 blkz.type = BLK_ZONE_TYPE_SEQWRITE_REQ;
780 blkz.capacity = zlo->zone_capacity;
781 }
782
783 mutex_unlock(lock: &zone->lock);
784
785 ret = disk_report_zone(disk, zone: &blkz, idx: i, args);
786 if (ret)
787 return ret;
788 }
789
790 return nr_zones;
791}
792
793static void zloop_free_disk(struct gendisk *disk)
794{
795 struct zloop_device *zlo = disk->private_data;
796 unsigned int i;
797
798 blk_mq_free_tag_set(set: &zlo->tag_set);
799
800 for (i = 0; i < zlo->nr_zones; i++) {
801 struct zloop_zone *zone = &zlo->zones[i];
802
803 mapping_set_gfp_mask(m: zone->file->f_mapping,
804 mask: zone->old_gfp_mask);
805 fput(zone->file);
806 }
807
808 fput(zlo->data_dir);
809 destroy_workqueue(wq: zlo->workqueue);
810 kfree(objp: zlo->base_dir);
811 kvfree(addr: zlo);
812}
813
814static const struct block_device_operations zloop_fops = {
815 .owner = THIS_MODULE,
816 .open = zloop_open,
817 .report_zones = zloop_report_zones,
818 .free_disk = zloop_free_disk,
819};
820
821__printf(3, 4)
822static struct file *zloop_filp_open_fmt(int oflags, umode_t mode,
823 const char *fmt, ...)
824{
825 struct file *file;
826 va_list ap;
827 char *p;
828
829 va_start(ap, fmt);
830 p = kvasprintf(GFP_KERNEL, fmt, args: ap);
831 va_end(ap);
832
833 if (!p)
834 return ERR_PTR(error: -ENOMEM);
835 file = filp_open(p, oflags, mode);
836 kfree(objp: p);
837 return file;
838}
839
840static int zloop_get_block_size(struct zloop_device *zlo,
841 struct zloop_zone *zone)
842{
843 struct block_device *sb_bdev = zone->file->f_mapping->host->i_sb->s_bdev;
844 struct kstat st;
845
846 /*
847 * If the FS block size is lower than or equal to 4K, use that as the
848 * device block size. Otherwise, fallback to the FS direct IO alignment
849 * constraint if that is provided, and to the FS underlying device
850 * physical block size if the direct IO alignment is unknown.
851 */
852 if (file_inode(f: zone->file)->i_sb->s_blocksize <= SZ_4K)
853 zlo->block_size = file_inode(f: zone->file)->i_sb->s_blocksize;
854 else if (!vfs_getattr(&zone->file->f_path, &st, STATX_DIOALIGN, 0) &&
855 (st.result_mask & STATX_DIOALIGN))
856 zlo->block_size = st.dio_offset_align;
857 else if (sb_bdev)
858 zlo->block_size = bdev_physical_block_size(bdev: sb_bdev);
859 else
860 zlo->block_size = SECTOR_SIZE;
861
862 if (zlo->zone_capacity & ((zlo->block_size >> SECTOR_SHIFT) - 1)) {
863 pr_err("Zone capacity is not aligned to block size %u\n",
864 zlo->block_size);
865 return -EINVAL;
866 }
867
868 return 0;
869}
870
871static int zloop_init_zone(struct zloop_device *zlo, struct zloop_options *opts,
872 unsigned int zone_no, bool restore)
873{
874 struct zloop_zone *zone = &zlo->zones[zone_no];
875 int oflags = O_RDWR;
876 struct kstat stat;
877 sector_t file_sectors;
878 int ret;
879
880 mutex_init(&zone->lock);
881 spin_lock_init(&zone->wp_lock);
882 zone->start = (sector_t)zone_no << zlo->zone_shift;
883
884 if (!restore)
885 oflags |= O_CREAT;
886
887 if (!opts->buffered_io)
888 oflags |= O_DIRECT;
889
890 if (zone_no < zlo->nr_conv_zones) {
891 /* Conventional zone file. */
892 set_bit(nr: ZLOOP_ZONE_CONV, addr: &zone->flags);
893 zone->cond = BLK_ZONE_COND_NOT_WP;
894 zone->wp = U64_MAX;
895
896 zone->file = zloop_filp_open_fmt(oflags, mode: 0600, fmt: "%s/%u/cnv-%06u",
897 zlo->base_dir, zlo->id, zone_no);
898 if (IS_ERR(ptr: zone->file)) {
899 pr_err("Failed to open zone %u file %s/%u/cnv-%06u (err=%ld)",
900 zone_no, zlo->base_dir, zlo->id, zone_no,
901 PTR_ERR(zone->file));
902 return PTR_ERR(ptr: zone->file);
903 }
904
905 if (!zlo->block_size) {
906 ret = zloop_get_block_size(zlo, zone);
907 if (ret)
908 return ret;
909 }
910
911 ret = vfs_getattr(&zone->file->f_path, &stat, STATX_SIZE, 0);
912 if (ret < 0) {
913 pr_err("Failed to get zone %u file stat\n", zone_no);
914 return ret;
915 }
916 file_sectors = stat.size >> SECTOR_SHIFT;
917
918 if (restore && file_sectors != zlo->zone_size) {
919 pr_err("Invalid conventional zone %u file size (%llu sectors != %llu)\n",
920 zone_no, file_sectors, zlo->zone_capacity);
921 return ret;
922 }
923
924 ret = vfs_truncate(&zone->file->f_path,
925 zlo->zone_size << SECTOR_SHIFT);
926 if (ret < 0) {
927 pr_err("Failed to truncate zone %u file (err=%d)\n",
928 zone_no, ret);
929 return ret;
930 }
931
932 return 0;
933 }
934
935 /* Sequential zone file. */
936 zone->file = zloop_filp_open_fmt(oflags, mode: 0600, fmt: "%s/%u/seq-%06u",
937 zlo->base_dir, zlo->id, zone_no);
938 if (IS_ERR(ptr: zone->file)) {
939 pr_err("Failed to open zone %u file %s/%u/seq-%06u (err=%ld)",
940 zone_no, zlo->base_dir, zlo->id, zone_no,
941 PTR_ERR(zone->file));
942 return PTR_ERR(ptr: zone->file);
943 }
944
945 if (!zlo->block_size) {
946 ret = zloop_get_block_size(zlo, zone);
947 if (ret)
948 return ret;
949 }
950
951 zloop_get_block_size(zlo, zone);
952
953 mutex_lock(&zone->lock);
954 ret = zloop_update_seq_zone(zlo, zone_no);
955 mutex_unlock(lock: &zone->lock);
956
957 return ret;
958}
959
960static bool zloop_dev_exists(struct zloop_device *zlo)
961{
962 struct file *cnv, *seq;
963 bool exists;
964
965 cnv = zloop_filp_open_fmt(O_RDONLY, mode: 0600, fmt: "%s/%u/cnv-%06u",
966 zlo->base_dir, zlo->id, 0);
967 seq = zloop_filp_open_fmt(O_RDONLY, mode: 0600, fmt: "%s/%u/seq-%06u",
968 zlo->base_dir, zlo->id, 0);
969 exists = !IS_ERR(ptr: cnv) || !IS_ERR(ptr: seq);
970
971 if (!IS_ERR(ptr: cnv))
972 fput(cnv);
973 if (!IS_ERR(ptr: seq))
974 fput(seq);
975
976 return exists;
977}
978
979static int zloop_ctl_add(struct zloop_options *opts)
980{
981 struct queue_limits lim = {
982 .max_hw_sectors = SZ_1M >> SECTOR_SHIFT,
983 .chunk_sectors = opts->zone_size,
984 .features = BLK_FEAT_ZONED,
985 };
986 unsigned int nr_zones, i, j;
987 struct zloop_device *zlo;
988 int ret = -EINVAL;
989 bool restore;
990
991 __module_get(THIS_MODULE);
992
993 nr_zones = opts->capacity >> ilog2(opts->zone_size);
994 if (opts->nr_conv_zones >= nr_zones) {
995 pr_err("Invalid number of conventional zones %u\n",
996 opts->nr_conv_zones);
997 goto out;
998 }
999
1000 zlo = kvzalloc(struct_size(zlo, zones, nr_zones), GFP_KERNEL);
1001 if (!zlo) {
1002 ret = -ENOMEM;
1003 goto out;
1004 }
1005 WRITE_ONCE(zlo->state, Zlo_creating);
1006
1007 ret = mutex_lock_killable(&zloop_ctl_mutex);
1008 if (ret)
1009 goto out_free_dev;
1010
1011 /* Allocate id, if @opts->id >= 0, we're requesting that specific id */
1012 if (opts->id >= 0) {
1013 ret = idr_alloc(&zloop_index_idr, ptr: zlo,
1014 start: opts->id, end: opts->id + 1, GFP_KERNEL);
1015 if (ret == -ENOSPC)
1016 ret = -EEXIST;
1017 } else {
1018 ret = idr_alloc(&zloop_index_idr, ptr: zlo, start: 0, end: 0, GFP_KERNEL);
1019 }
1020 mutex_unlock(lock: &zloop_ctl_mutex);
1021 if (ret < 0)
1022 goto out_free_dev;
1023
1024 zlo->id = ret;
1025 zlo->zone_shift = ilog2(opts->zone_size);
1026 zlo->zone_size = opts->zone_size;
1027 if (opts->zone_capacity)
1028 zlo->zone_capacity = opts->zone_capacity;
1029 else
1030 zlo->zone_capacity = zlo->zone_size;
1031 zlo->nr_zones = nr_zones;
1032 zlo->nr_conv_zones = opts->nr_conv_zones;
1033 zlo->buffered_io = opts->buffered_io;
1034 zlo->zone_append = opts->zone_append;
1035 if (zlo->zone_append)
1036 zlo->ordered_zone_append = opts->ordered_zone_append;
1037
1038 zlo->workqueue = alloc_workqueue("zloop%d", WQ_UNBOUND | WQ_FREEZABLE,
1039 opts->nr_queues * opts->queue_depth, zlo->id);
1040 if (!zlo->workqueue) {
1041 ret = -ENOMEM;
1042 goto out_free_idr;
1043 }
1044
1045 if (opts->base_dir)
1046 zlo->base_dir = kstrdup(s: opts->base_dir, GFP_KERNEL);
1047 else
1048 zlo->base_dir = kstrdup(ZLOOP_DEF_BASE_DIR, GFP_KERNEL);
1049 if (!zlo->base_dir) {
1050 ret = -ENOMEM;
1051 goto out_destroy_workqueue;
1052 }
1053
1054 zlo->data_dir = zloop_filp_open_fmt(O_RDONLY | O_DIRECTORY, mode: 0, fmt: "%s/%u",
1055 zlo->base_dir, zlo->id);
1056 if (IS_ERR(ptr: zlo->data_dir)) {
1057 ret = PTR_ERR(ptr: zlo->data_dir);
1058 pr_warn("Failed to open directory %s/%u (err=%d)\n",
1059 zlo->base_dir, zlo->id, ret);
1060 goto out_free_base_dir;
1061 }
1062
1063 /*
1064 * If we already have zone files, we are restoring a device created by a
1065 * previous add operation. In this case, zloop_init_zone() will check
1066 * that the zone files are consistent with the zone configuration given.
1067 */
1068 restore = zloop_dev_exists(zlo);
1069 for (i = 0; i < nr_zones; i++) {
1070 ret = zloop_init_zone(zlo, opts, zone_no: i, restore);
1071 if (ret)
1072 goto out_close_files;
1073 }
1074
1075 lim.physical_block_size = zlo->block_size;
1076 lim.logical_block_size = zlo->block_size;
1077 if (zlo->zone_append)
1078 lim.max_hw_zone_append_sectors = lim.max_hw_sectors;
1079
1080 zlo->tag_set.ops = &zloop_mq_ops;
1081 zlo->tag_set.nr_hw_queues = opts->nr_queues;
1082 zlo->tag_set.queue_depth = opts->queue_depth;
1083 zlo->tag_set.numa_node = NUMA_NO_NODE;
1084 zlo->tag_set.cmd_size = sizeof(struct zloop_cmd);
1085 zlo->tag_set.driver_data = zlo;
1086
1087 ret = blk_mq_alloc_tag_set(set: &zlo->tag_set);
1088 if (ret) {
1089 pr_err("blk_mq_alloc_tag_set failed (err=%d)\n", ret);
1090 goto out_close_files;
1091 }
1092
1093 zlo->disk = blk_mq_alloc_disk(&zlo->tag_set, &lim, zlo);
1094 if (IS_ERR(ptr: zlo->disk)) {
1095 pr_err("blk_mq_alloc_disk failed (err=%d)\n", ret);
1096 ret = PTR_ERR(ptr: zlo->disk);
1097 goto out_cleanup_tags;
1098 }
1099 zlo->disk->flags = GENHD_FL_NO_PART;
1100 zlo->disk->fops = &zloop_fops;
1101 zlo->disk->private_data = zlo;
1102 sprintf(buf: zlo->disk->disk_name, fmt: "zloop%d", zlo->id);
1103 set_capacity(disk: zlo->disk, size: (u64)lim.chunk_sectors * zlo->nr_zones);
1104
1105 ret = blk_revalidate_disk_zones(disk: zlo->disk);
1106 if (ret)
1107 goto out_cleanup_disk;
1108
1109 ret = add_disk(disk: zlo->disk);
1110 if (ret) {
1111 pr_err("add_disk failed (err=%d)\n", ret);
1112 goto out_cleanup_disk;
1113 }
1114
1115 mutex_lock(&zloop_ctl_mutex);
1116 WRITE_ONCE(zlo->state, Zlo_live);
1117 mutex_unlock(lock: &zloop_ctl_mutex);
1118
1119 pr_info("zloop: device %d, %u zones of %llu MiB, %u B block size\n",
1120 zlo->id, zlo->nr_zones,
1121 ((sector_t)zlo->zone_size << SECTOR_SHIFT) >> 20,
1122 zlo->block_size);
1123 pr_info("zloop%d: using %s%s zone append\n",
1124 zlo->id,
1125 zlo->ordered_zone_append ? "ordered " : "",
1126 zlo->zone_append ? "native" : "emulated");
1127
1128 return 0;
1129
1130out_cleanup_disk:
1131 put_disk(disk: zlo->disk);
1132out_cleanup_tags:
1133 blk_mq_free_tag_set(set: &zlo->tag_set);
1134out_close_files:
1135 for (j = 0; j < i; j++) {
1136 struct zloop_zone *zone = &zlo->zones[j];
1137
1138 if (!IS_ERR_OR_NULL(ptr: zone->file))
1139 fput(zone->file);
1140 }
1141 fput(zlo->data_dir);
1142out_free_base_dir:
1143 kfree(objp: zlo->base_dir);
1144out_destroy_workqueue:
1145 destroy_workqueue(wq: zlo->workqueue);
1146out_free_idr:
1147 mutex_lock(&zloop_ctl_mutex);
1148 idr_remove(&zloop_index_idr, id: zlo->id);
1149 mutex_unlock(lock: &zloop_ctl_mutex);
1150out_free_dev:
1151 kvfree(addr: zlo);
1152out:
1153 module_put(THIS_MODULE);
1154 if (ret == -ENOENT)
1155 ret = -EINVAL;
1156 return ret;
1157}
1158
1159static int zloop_ctl_remove(struct zloop_options *opts)
1160{
1161 struct zloop_device *zlo;
1162 int ret;
1163
1164 if (!(opts->mask & ZLOOP_OPT_ID)) {
1165 pr_err("No ID specified\n");
1166 return -EINVAL;
1167 }
1168
1169 ret = mutex_lock_killable(&zloop_ctl_mutex);
1170 if (ret)
1171 return ret;
1172
1173 zlo = idr_find(&zloop_index_idr, id: opts->id);
1174 if (!zlo || zlo->state == Zlo_creating) {
1175 ret = -ENODEV;
1176 } else if (zlo->state == Zlo_deleting) {
1177 ret = -EINVAL;
1178 } else {
1179 idr_remove(&zloop_index_idr, id: zlo->id);
1180 WRITE_ONCE(zlo->state, Zlo_deleting);
1181 }
1182
1183 mutex_unlock(lock: &zloop_ctl_mutex);
1184 if (ret)
1185 return ret;
1186
1187 del_gendisk(gp: zlo->disk);
1188 put_disk(disk: zlo->disk);
1189
1190 pr_info("Removed device %d\n", opts->id);
1191
1192 module_put(THIS_MODULE);
1193
1194 return 0;
1195}
1196
1197static int zloop_parse_options(struct zloop_options *opts, const char *buf)
1198{
1199 substring_t args[MAX_OPT_ARGS];
1200 char *options, *o, *p;
1201 unsigned int token;
1202 int ret = 0;
1203
1204 /* Set defaults. */
1205 opts->mask = 0;
1206 opts->id = ZLOOP_DEF_ID;
1207 opts->capacity = ZLOOP_DEF_ZONE_SIZE * ZLOOP_DEF_NR_ZONES;
1208 opts->zone_size = ZLOOP_DEF_ZONE_SIZE;
1209 opts->nr_conv_zones = ZLOOP_DEF_NR_CONV_ZONES;
1210 opts->nr_queues = ZLOOP_DEF_NR_QUEUES;
1211 opts->queue_depth = ZLOOP_DEF_QUEUE_DEPTH;
1212 opts->buffered_io = ZLOOP_DEF_BUFFERED_IO;
1213 opts->zone_append = ZLOOP_DEF_ZONE_APPEND;
1214 opts->ordered_zone_append = ZLOOP_DEF_ORDERED_ZONE_APPEND;
1215
1216 if (!buf)
1217 return 0;
1218
1219 /* Skip leading spaces before the options. */
1220 while (isspace(*buf))
1221 buf++;
1222
1223 options = o = kstrdup(s: buf, GFP_KERNEL);
1224 if (!options)
1225 return -ENOMEM;
1226
1227 /* Parse the options, doing only some light invalid value checks. */
1228 while ((p = strsep(&o, ",\n")) != NULL) {
1229 if (!*p)
1230 continue;
1231
1232 token = match_token(p, table: zloop_opt_tokens, args);
1233 opts->mask |= token;
1234 switch (token) {
1235 case ZLOOP_OPT_ID:
1236 if (match_int(args, result: &opts->id)) {
1237 ret = -EINVAL;
1238 goto out;
1239 }
1240 break;
1241 case ZLOOP_OPT_CAPACITY:
1242 if (match_uint(s: args, result: &token)) {
1243 ret = -EINVAL;
1244 goto out;
1245 }
1246 if (!token) {
1247 pr_err("Invalid capacity\n");
1248 ret = -EINVAL;
1249 goto out;
1250 }
1251 opts->capacity =
1252 ((sector_t)token * SZ_1M) >> SECTOR_SHIFT;
1253 break;
1254 case ZLOOP_OPT_ZONE_SIZE:
1255 if (match_uint(s: args, result: &token)) {
1256 ret = -EINVAL;
1257 goto out;
1258 }
1259 if (!token || token > ZLOOP_MAX_ZONE_SIZE_MB ||
1260 !is_power_of_2(n: token)) {
1261 pr_err("Invalid zone size %u\n", token);
1262 ret = -EINVAL;
1263 goto out;
1264 }
1265 opts->zone_size =
1266 ((sector_t)token * SZ_1M) >> SECTOR_SHIFT;
1267 break;
1268 case ZLOOP_OPT_ZONE_CAPACITY:
1269 if (match_uint(s: args, result: &token)) {
1270 ret = -EINVAL;
1271 goto out;
1272 }
1273 if (!token) {
1274 pr_err("Invalid zone capacity\n");
1275 ret = -EINVAL;
1276 goto out;
1277 }
1278 opts->zone_capacity =
1279 ((sector_t)token * SZ_1M) >> SECTOR_SHIFT;
1280 break;
1281 case ZLOOP_OPT_NR_CONV_ZONES:
1282 if (match_uint(s: args, result: &token)) {
1283 ret = -EINVAL;
1284 goto out;
1285 }
1286 opts->nr_conv_zones = token;
1287 break;
1288 case ZLOOP_OPT_BASE_DIR:
1289 p = match_strdup(args);
1290 if (!p) {
1291 ret = -ENOMEM;
1292 goto out;
1293 }
1294 kfree(objp: opts->base_dir);
1295 opts->base_dir = p;
1296 break;
1297 case ZLOOP_OPT_NR_QUEUES:
1298 if (match_uint(s: args, result: &token)) {
1299 ret = -EINVAL;
1300 goto out;
1301 }
1302 if (!token) {
1303 pr_err("Invalid number of queues\n");
1304 ret = -EINVAL;
1305 goto out;
1306 }
1307 opts->nr_queues = min(token, num_online_cpus());
1308 break;
1309 case ZLOOP_OPT_QUEUE_DEPTH:
1310 if (match_uint(s: args, result: &token)) {
1311 ret = -EINVAL;
1312 goto out;
1313 }
1314 if (!token) {
1315 pr_err("Invalid queue depth\n");
1316 ret = -EINVAL;
1317 goto out;
1318 }
1319 opts->queue_depth = token;
1320 break;
1321 case ZLOOP_OPT_BUFFERED_IO:
1322 opts->buffered_io = true;
1323 break;
1324 case ZLOOP_OPT_ZONE_APPEND:
1325 if (match_uint(s: args, result: &token)) {
1326 ret = -EINVAL;
1327 goto out;
1328 }
1329 if (token != 0 && token != 1) {
1330 pr_err("Invalid zone_append value\n");
1331 ret = -EINVAL;
1332 goto out;
1333 }
1334 opts->zone_append = token;
1335 break;
1336 case ZLOOP_OPT_ORDERED_ZONE_APPEND:
1337 opts->ordered_zone_append = true;
1338 break;
1339 case ZLOOP_OPT_ERR:
1340 default:
1341 pr_warn("unknown parameter or missing value '%s'\n", p);
1342 ret = -EINVAL;
1343 goto out;
1344 }
1345 }
1346
1347 ret = -EINVAL;
1348 if (opts->capacity <= opts->zone_size) {
1349 pr_err("Invalid capacity\n");
1350 goto out;
1351 }
1352
1353 if (opts->zone_capacity > opts->zone_size) {
1354 pr_err("Invalid zone capacity\n");
1355 goto out;
1356 }
1357
1358 ret = 0;
1359out:
1360 kfree(objp: options);
1361 return ret;
1362}
1363
1364enum {
1365 ZLOOP_CTL_ADD,
1366 ZLOOP_CTL_REMOVE,
1367};
1368
1369static struct zloop_ctl_op {
1370 int code;
1371 const char *name;
1372} zloop_ctl_ops[] = {
1373 { ZLOOP_CTL_ADD, "add" },
1374 { ZLOOP_CTL_REMOVE, "remove" },
1375 { -1, NULL },
1376};
1377
1378static ssize_t zloop_ctl_write(struct file *file, const char __user *ubuf,
1379 size_t count, loff_t *pos)
1380{
1381 struct zloop_options opts = { };
1382 struct zloop_ctl_op *op;
1383 const char *buf, *opts_buf;
1384 int i, ret;
1385
1386 if (count > PAGE_SIZE)
1387 return -ENOMEM;
1388
1389 buf = memdup_user_nul(ubuf, count);
1390 if (IS_ERR(ptr: buf))
1391 return PTR_ERR(ptr: buf);
1392
1393 for (i = 0; i < ARRAY_SIZE(zloop_ctl_ops); i++) {
1394 op = &zloop_ctl_ops[i];
1395 if (!op->name) {
1396 pr_err("Invalid operation\n");
1397 ret = -EINVAL;
1398 goto out;
1399 }
1400 if (!strncmp(buf, op->name, strlen(op->name)))
1401 break;
1402 }
1403
1404 if (count <= strlen(op->name))
1405 opts_buf = NULL;
1406 else
1407 opts_buf = buf + strlen(op->name);
1408
1409 ret = zloop_parse_options(opts: &opts, buf: opts_buf);
1410 if (ret) {
1411 pr_err("Failed to parse options\n");
1412 goto out;
1413 }
1414
1415 switch (op->code) {
1416 case ZLOOP_CTL_ADD:
1417 ret = zloop_ctl_add(opts: &opts);
1418 break;
1419 case ZLOOP_CTL_REMOVE:
1420 ret = zloop_ctl_remove(opts: &opts);
1421 break;
1422 default:
1423 pr_err("Invalid operation\n");
1424 ret = -EINVAL;
1425 goto out;
1426 }
1427
1428out:
1429 kfree(objp: opts.base_dir);
1430 kfree(objp: buf);
1431 return ret ? ret : count;
1432}
1433
1434static int zloop_ctl_show(struct seq_file *seq_file, void *private)
1435{
1436 const struct match_token *tok;
1437 int i;
1438
1439 /* Add operation */
1440 seq_printf(m: seq_file, fmt: "%s ", zloop_ctl_ops[0].name);
1441 for (i = 0; i < ARRAY_SIZE(zloop_opt_tokens); i++) {
1442 tok = &zloop_opt_tokens[i];
1443 if (!tok->pattern)
1444 break;
1445 if (i)
1446 seq_putc(m: seq_file, c: ',');
1447 seq_puts(m: seq_file, s: tok->pattern);
1448 }
1449 seq_putc(m: seq_file, c: '\n');
1450
1451 /* Remove operation */
1452 seq_puts(m: seq_file, s: zloop_ctl_ops[1].name);
1453 seq_puts(m: seq_file, s: " id=%d\n");
1454
1455 return 0;
1456}
1457
1458static int zloop_ctl_open(struct inode *inode, struct file *file)
1459{
1460 file->private_data = NULL;
1461 return single_open(file, zloop_ctl_show, NULL);
1462}
1463
1464static int zloop_ctl_release(struct inode *inode, struct file *file)
1465{
1466 return single_release(inode, file);
1467}
1468
1469static const struct file_operations zloop_ctl_fops = {
1470 .owner = THIS_MODULE,
1471 .open = zloop_ctl_open,
1472 .release = zloop_ctl_release,
1473 .write = zloop_ctl_write,
1474 .read = seq_read,
1475};
1476
1477static struct miscdevice zloop_misc = {
1478 .minor = MISC_DYNAMIC_MINOR,
1479 .name = "zloop-control",
1480 .fops = &zloop_ctl_fops,
1481};
1482
1483static int __init zloop_init(void)
1484{
1485 int ret;
1486
1487 ret = misc_register(misc: &zloop_misc);
1488 if (ret) {
1489 pr_err("Failed to register misc device: %d\n", ret);
1490 return ret;
1491 }
1492 pr_info("Module loaded\n");
1493
1494 return 0;
1495}
1496
1497static void __exit zloop_exit(void)
1498{
1499 misc_deregister(misc: &zloop_misc);
1500 idr_destroy(&zloop_index_idr);
1501}
1502
1503module_init(zloop_init);
1504module_exit(zloop_exit);
1505
1506MODULE_DESCRIPTION("Zoned loopback device");
1507MODULE_LICENSE("GPL");
1508

source code of linux/drivers/block/zloop.c