1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Userspace block device - block device which IO is handled from userspace
4 *
5 * Take full use of io_uring passthrough command for communicating with
6 * ublk userspace daemon(ublksrvd) for handling basic IO request.
7 *
8 * Copyright 2022 Ming Lei <ming.lei@redhat.com>
9 *
10 * (part of code stolen from loop.c)
11 */
12 #include <linux/module.h>
13 #include <linux/moduleparam.h>
14 #include <linux/sched.h>
15 #include <linux/fs.h>
16 #include <linux/pagemap.h>
17 #include <linux/file.h>
18 #include <linux/stat.h>
19 #include <linux/errno.h>
20 #include <linux/major.h>
21 #include <linux/wait.h>
22 #include <linux/blkdev.h>
23 #include <linux/init.h>
24 #include <linux/swap.h>
25 #include <linux/slab.h>
26 #include <linux/compat.h>
27 #include <linux/mutex.h>
28 #include <linux/writeback.h>
29 #include <linux/completion.h>
30 #include <linux/highmem.h>
31 #include <linux/sysfs.h>
32 #include <linux/miscdevice.h>
33 #include <linux/falloc.h>
34 #include <linux/uio.h>
35 #include <linux/ioprio.h>
36 #include <linux/sched/mm.h>
37 #include <linux/uaccess.h>
38 #include <linux/cdev.h>
39 #include <linux/io_uring/cmd.h>
40 #include <linux/blk-mq.h>
41 #include <linux/delay.h>
42 #include <linux/mm.h>
43 #include <asm/page.h>
44 #include <linux/task_work.h>
45 #include <linux/namei.h>
46 #include <linux/kref.h>
47 #include <uapi/linux/ublk_cmd.h>
48
49 #define UBLK_MINORS (1U << MINORBITS)
50
51 /* All UBLK_F_* have to be included into UBLK_F_ALL */
52 #define UBLK_F_ALL (UBLK_F_SUPPORT_ZERO_COPY \
53 | UBLK_F_URING_CMD_COMP_IN_TASK \
54 | UBLK_F_NEED_GET_DATA \
55 | UBLK_F_USER_RECOVERY \
56 | UBLK_F_USER_RECOVERY_REISSUE \
57 | UBLK_F_UNPRIVILEGED_DEV \
58 | UBLK_F_CMD_IOCTL_ENCODE \
59 | UBLK_F_USER_COPY \
60 | UBLK_F_ZONED)
61
62 /* All UBLK_PARAM_TYPE_* should be included here */
63 #define UBLK_PARAM_TYPE_ALL \
64 (UBLK_PARAM_TYPE_BASIC | UBLK_PARAM_TYPE_DISCARD | \
65 UBLK_PARAM_TYPE_DEVT | UBLK_PARAM_TYPE_ZONED)
66
67 struct ublk_rq_data {
68 struct llist_node node;
69
70 struct kref ref;
71 __u64 sector;
72 __u32 operation;
73 __u32 nr_zones;
74 };
75
76 struct ublk_uring_cmd_pdu {
77 struct ublk_queue *ubq;
78 u16 tag;
79 };
80
81 /*
82 * io command is active: sqe cmd is received, and its cqe isn't done
83 *
84 * If the flag is set, the io command is owned by ublk driver, and waited
85 * for incoming blk-mq request from the ublk block device.
86 *
87 * If the flag is cleared, the io command will be completed, and owned by
88 * ublk server.
89 */
90 #define UBLK_IO_FLAG_ACTIVE 0x01
91
92 /*
93 * IO command is completed via cqe, and it is being handled by ublksrv, and
94 * not committed yet
95 *
96 * Basically exclusively with UBLK_IO_FLAG_ACTIVE, so can be served for
97 * cross verification
98 */
99 #define UBLK_IO_FLAG_OWNED_BY_SRV 0x02
100
101 /*
102 * IO command is aborted, so this flag is set in case of
103 * !UBLK_IO_FLAG_ACTIVE.
104 *
105 * After this flag is observed, any pending or new incoming request
106 * associated with this io command will be failed immediately
107 */
108 #define UBLK_IO_FLAG_ABORTED 0x04
109
110 /*
111 * UBLK_IO_FLAG_NEED_GET_DATA is set because IO command requires
112 * get data buffer address from ublksrv.
113 *
114 * Then, bio data could be copied into this data buffer for a WRITE request
115 * after the IO command is issued again and UBLK_IO_FLAG_NEED_GET_DATA is unset.
116 */
117 #define UBLK_IO_FLAG_NEED_GET_DATA 0x08
118
119 /* atomic RW with ubq->cancel_lock */
120 #define UBLK_IO_FLAG_CANCELED 0x80000000
121
122 struct ublk_io {
123 /* userspace buffer address from io cmd */
124 __u64 addr;
125 unsigned int flags;
126 int res;
127
128 struct io_uring_cmd *cmd;
129 };
130
131 struct ublk_queue {
132 int q_id;
133 int q_depth;
134
135 unsigned long flags;
136 struct task_struct *ubq_daemon;
137 char *io_cmd_buf;
138
139 struct llist_head io_cmds;
140
141 unsigned long io_addr; /* mapped vm address */
142 unsigned int max_io_sz;
143 bool force_abort;
144 bool timeout;
145 bool canceling;
146 unsigned short nr_io_ready; /* how many ios setup */
147 spinlock_t cancel_lock;
148 struct ublk_device *dev;
149 struct ublk_io ios[];
150 };
151
152 struct ublk_device {
153 struct gendisk *ub_disk;
154
155 char *__queues;
156
157 unsigned int queue_size;
158 struct ublksrv_ctrl_dev_info dev_info;
159
160 struct blk_mq_tag_set tag_set;
161
162 struct cdev cdev;
163 struct device cdev_dev;
164
165 #define UB_STATE_OPEN 0
166 #define UB_STATE_USED 1
167 #define UB_STATE_DELETED 2
168 unsigned long state;
169 int ub_number;
170
171 struct mutex mutex;
172
173 spinlock_t lock;
174 struct mm_struct *mm;
175
176 struct ublk_params params;
177
178 struct completion completion;
179 unsigned int nr_queues_ready;
180 unsigned int nr_privileged_daemon;
181
182 struct work_struct quiesce_work;
183 struct work_struct stop_work;
184 };
185
186 /* header of ublk_params */
187 struct ublk_params_header {
188 __u32 len;
189 __u32 types;
190 };
191
192 static bool ublk_abort_requests(struct ublk_device *ub, struct ublk_queue *ubq);
193
194 static inline unsigned int ublk_req_build_flags(struct request *req);
195 static inline struct ublksrv_io_desc *ublk_get_iod(struct ublk_queue *ubq,
196 int tag);
ublk_dev_is_user_copy(const struct ublk_device * ub)197 static inline bool ublk_dev_is_user_copy(const struct ublk_device *ub)
198 {
199 return ub->dev_info.flags & UBLK_F_USER_COPY;
200 }
201
ublk_dev_is_zoned(const struct ublk_device * ub)202 static inline bool ublk_dev_is_zoned(const struct ublk_device *ub)
203 {
204 return ub->dev_info.flags & UBLK_F_ZONED;
205 }
206
ublk_queue_is_zoned(struct ublk_queue * ubq)207 static inline bool ublk_queue_is_zoned(struct ublk_queue *ubq)
208 {
209 return ubq->flags & UBLK_F_ZONED;
210 }
211
212 #ifdef CONFIG_BLK_DEV_ZONED
213
ublk_get_nr_zones(const struct ublk_device * ub)214 static int ublk_get_nr_zones(const struct ublk_device *ub)
215 {
216 const struct ublk_param_basic *p = &ub->params.basic;
217
218 /* Zone size is a power of 2 */
219 return p->dev_sectors >> ilog2(p->chunk_sectors);
220 }
221
ublk_revalidate_disk_zones(struct ublk_device * ub)222 static int ublk_revalidate_disk_zones(struct ublk_device *ub)
223 {
224 return blk_revalidate_disk_zones(ub->ub_disk, NULL);
225 }
226
ublk_dev_param_zoned_validate(const struct ublk_device * ub)227 static int ublk_dev_param_zoned_validate(const struct ublk_device *ub)
228 {
229 const struct ublk_param_zoned *p = &ub->params.zoned;
230 int nr_zones;
231
232 if (!ublk_dev_is_zoned(ub))
233 return -EINVAL;
234
235 if (!p->max_zone_append_sectors)
236 return -EINVAL;
237
238 nr_zones = ublk_get_nr_zones(ub);
239
240 if (p->max_active_zones > nr_zones)
241 return -EINVAL;
242
243 if (p->max_open_zones > nr_zones)
244 return -EINVAL;
245
246 return 0;
247 }
248
ublk_dev_param_zoned_apply(struct ublk_device * ub)249 static int ublk_dev_param_zoned_apply(struct ublk_device *ub)
250 {
251 const struct ublk_param_zoned *p = &ub->params.zoned;
252
253 disk_set_zoned(ub->ub_disk);
254 blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, ub->ub_disk->queue);
255 blk_queue_required_elevator_features(ub->ub_disk->queue,
256 ELEVATOR_F_ZBD_SEQ_WRITE);
257 disk_set_max_active_zones(ub->ub_disk, p->max_active_zones);
258 disk_set_max_open_zones(ub->ub_disk, p->max_open_zones);
259 blk_queue_max_zone_append_sectors(ub->ub_disk->queue, p->max_zone_append_sectors);
260
261 ub->ub_disk->nr_zones = ublk_get_nr_zones(ub);
262
263 return 0;
264 }
265
266 /* Based on virtblk_alloc_report_buffer */
ublk_alloc_report_buffer(struct ublk_device * ublk,unsigned int nr_zones,size_t * buflen)267 static void *ublk_alloc_report_buffer(struct ublk_device *ublk,
268 unsigned int nr_zones, size_t *buflen)
269 {
270 struct request_queue *q = ublk->ub_disk->queue;
271 size_t bufsize;
272 void *buf;
273
274 nr_zones = min_t(unsigned int, nr_zones,
275 ublk->ub_disk->nr_zones);
276
277 bufsize = nr_zones * sizeof(struct blk_zone);
278 bufsize =
279 min_t(size_t, bufsize, queue_max_hw_sectors(q) << SECTOR_SHIFT);
280
281 while (bufsize >= sizeof(struct blk_zone)) {
282 buf = kvmalloc(bufsize, GFP_KERNEL | __GFP_NORETRY);
283 if (buf) {
284 *buflen = bufsize;
285 return buf;
286 }
287 bufsize >>= 1;
288 }
289
290 *buflen = 0;
291 return NULL;
292 }
293
ublk_report_zones(struct gendisk * disk,sector_t sector,unsigned int nr_zones,report_zones_cb cb,void * data)294 static int ublk_report_zones(struct gendisk *disk, sector_t sector,
295 unsigned int nr_zones, report_zones_cb cb, void *data)
296 {
297 struct ublk_device *ub = disk->private_data;
298 unsigned int zone_size_sectors = disk->queue->limits.chunk_sectors;
299 unsigned int first_zone = sector >> ilog2(zone_size_sectors);
300 unsigned int done_zones = 0;
301 unsigned int max_zones_per_request;
302 int ret;
303 struct blk_zone *buffer;
304 size_t buffer_length;
305
306 nr_zones = min_t(unsigned int, ub->ub_disk->nr_zones - first_zone,
307 nr_zones);
308
309 buffer = ublk_alloc_report_buffer(ub, nr_zones, &buffer_length);
310 if (!buffer)
311 return -ENOMEM;
312
313 max_zones_per_request = buffer_length / sizeof(struct blk_zone);
314
315 while (done_zones < nr_zones) {
316 unsigned int remaining_zones = nr_zones - done_zones;
317 unsigned int zones_in_request =
318 min_t(unsigned int, remaining_zones, max_zones_per_request);
319 struct request *req;
320 struct ublk_rq_data *pdu;
321 blk_status_t status;
322
323 memset(buffer, 0, buffer_length);
324
325 req = blk_mq_alloc_request(disk->queue, REQ_OP_DRV_IN, 0);
326 if (IS_ERR(req)) {
327 ret = PTR_ERR(req);
328 goto out;
329 }
330
331 pdu = blk_mq_rq_to_pdu(req);
332 pdu->operation = UBLK_IO_OP_REPORT_ZONES;
333 pdu->sector = sector;
334 pdu->nr_zones = zones_in_request;
335
336 ret = blk_rq_map_kern(disk->queue, req, buffer, buffer_length,
337 GFP_KERNEL);
338 if (ret) {
339 blk_mq_free_request(req);
340 goto out;
341 }
342
343 status = blk_execute_rq(req, 0);
344 ret = blk_status_to_errno(status);
345 blk_mq_free_request(req);
346 if (ret)
347 goto out;
348
349 for (unsigned int i = 0; i < zones_in_request; i++) {
350 struct blk_zone *zone = buffer + i;
351
352 /* A zero length zone means no more zones in this response */
353 if (!zone->len)
354 break;
355
356 ret = cb(zone, i, data);
357 if (ret)
358 goto out;
359
360 done_zones++;
361 sector += zone_size_sectors;
362
363 }
364 }
365
366 ret = done_zones;
367
368 out:
369 kvfree(buffer);
370 return ret;
371 }
372
ublk_setup_iod_zoned(struct ublk_queue * ubq,struct request * req)373 static blk_status_t ublk_setup_iod_zoned(struct ublk_queue *ubq,
374 struct request *req)
375 {
376 struct ublksrv_io_desc *iod = ublk_get_iod(ubq, req->tag);
377 struct ublk_io *io = &ubq->ios[req->tag];
378 struct ublk_rq_data *pdu = blk_mq_rq_to_pdu(req);
379 u32 ublk_op;
380
381 switch (req_op(req)) {
382 case REQ_OP_ZONE_OPEN:
383 ublk_op = UBLK_IO_OP_ZONE_OPEN;
384 break;
385 case REQ_OP_ZONE_CLOSE:
386 ublk_op = UBLK_IO_OP_ZONE_CLOSE;
387 break;
388 case REQ_OP_ZONE_FINISH:
389 ublk_op = UBLK_IO_OP_ZONE_FINISH;
390 break;
391 case REQ_OP_ZONE_RESET:
392 ublk_op = UBLK_IO_OP_ZONE_RESET;
393 break;
394 case REQ_OP_ZONE_APPEND:
395 ublk_op = UBLK_IO_OP_ZONE_APPEND;
396 break;
397 case REQ_OP_ZONE_RESET_ALL:
398 ublk_op = UBLK_IO_OP_ZONE_RESET_ALL;
399 break;
400 case REQ_OP_DRV_IN:
401 ublk_op = pdu->operation;
402 switch (ublk_op) {
403 case UBLK_IO_OP_REPORT_ZONES:
404 iod->op_flags = ublk_op | ublk_req_build_flags(req);
405 iod->nr_zones = pdu->nr_zones;
406 iod->start_sector = pdu->sector;
407 return BLK_STS_OK;
408 default:
409 return BLK_STS_IOERR;
410 }
411 case REQ_OP_DRV_OUT:
412 /* We do not support drv_out */
413 return BLK_STS_NOTSUPP;
414 default:
415 return BLK_STS_IOERR;
416 }
417
418 iod->op_flags = ublk_op | ublk_req_build_flags(req);
419 iod->nr_sectors = blk_rq_sectors(req);
420 iod->start_sector = blk_rq_pos(req);
421 iod->addr = io->addr;
422
423 return BLK_STS_OK;
424 }
425
426 #else
427
428 #define ublk_report_zones (NULL)
429
ublk_dev_param_zoned_validate(const struct ublk_device * ub)430 static int ublk_dev_param_zoned_validate(const struct ublk_device *ub)
431 {
432 return -EOPNOTSUPP;
433 }
434
ublk_dev_param_zoned_apply(struct ublk_device * ub)435 static int ublk_dev_param_zoned_apply(struct ublk_device *ub)
436 {
437 return -EOPNOTSUPP;
438 }
439
ublk_revalidate_disk_zones(struct ublk_device * ub)440 static int ublk_revalidate_disk_zones(struct ublk_device *ub)
441 {
442 return 0;
443 }
444
ublk_setup_iod_zoned(struct ublk_queue * ubq,struct request * req)445 static blk_status_t ublk_setup_iod_zoned(struct ublk_queue *ubq,
446 struct request *req)
447 {
448 return BLK_STS_NOTSUPP;
449 }
450
451 #endif
452
453 static inline void __ublk_complete_rq(struct request *req);
454 static void ublk_complete_rq(struct kref *ref);
455
456 static dev_t ublk_chr_devt;
457 static const struct class ublk_chr_class = {
458 .name = "ublk-char",
459 };
460
461 static DEFINE_IDR(ublk_index_idr);
462 static DEFINE_SPINLOCK(ublk_idr_lock);
463 static wait_queue_head_t ublk_idr_wq; /* wait until one idr is freed */
464
465 static DEFINE_MUTEX(ublk_ctl_mutex);
466
467 /*
468 * Max ublk devices allowed to add
469 *
470 * It can be extended to one per-user limit in future or even controlled
471 * by cgroup.
472 */
473 #define UBLK_MAX_UBLKS UBLK_MINORS
474 static unsigned int ublks_max = 64;
475 static unsigned int ublks_added; /* protected by ublk_ctl_mutex */
476
477 static struct miscdevice ublk_misc;
478
ublk_pos_to_hwq(loff_t pos)479 static inline unsigned ublk_pos_to_hwq(loff_t pos)
480 {
481 return ((pos - UBLKSRV_IO_BUF_OFFSET) >> UBLK_QID_OFF) &
482 UBLK_QID_BITS_MASK;
483 }
484
ublk_pos_to_buf_off(loff_t pos)485 static inline unsigned ublk_pos_to_buf_off(loff_t pos)
486 {
487 return (pos - UBLKSRV_IO_BUF_OFFSET) & UBLK_IO_BUF_BITS_MASK;
488 }
489
ublk_pos_to_tag(loff_t pos)490 static inline unsigned ublk_pos_to_tag(loff_t pos)
491 {
492 return ((pos - UBLKSRV_IO_BUF_OFFSET) >> UBLK_TAG_OFF) &
493 UBLK_TAG_BITS_MASK;
494 }
495
ublk_dev_param_basic_apply(struct ublk_device * ub)496 static void ublk_dev_param_basic_apply(struct ublk_device *ub)
497 {
498 struct request_queue *q = ub->ub_disk->queue;
499 const struct ublk_param_basic *p = &ub->params.basic;
500
501 blk_queue_logical_block_size(q, 1 << p->logical_bs_shift);
502 blk_queue_physical_block_size(q, 1 << p->physical_bs_shift);
503 blk_queue_io_min(q, 1 << p->io_min_shift);
504 blk_queue_io_opt(q, 1 << p->io_opt_shift);
505
506 blk_queue_write_cache(q, p->attrs & UBLK_ATTR_VOLATILE_CACHE,
507 p->attrs & UBLK_ATTR_FUA);
508 if (p->attrs & UBLK_ATTR_ROTATIONAL)
509 blk_queue_flag_clear(QUEUE_FLAG_NONROT, q);
510 else
511 blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
512
513 blk_queue_max_hw_sectors(q, p->max_sectors);
514 blk_queue_chunk_sectors(q, p->chunk_sectors);
515 blk_queue_virt_boundary(q, p->virt_boundary_mask);
516
517 if (p->attrs & UBLK_ATTR_READ_ONLY)
518 set_disk_ro(ub->ub_disk, true);
519
520 set_capacity(ub->ub_disk, p->dev_sectors);
521 }
522
ublk_dev_param_discard_apply(struct ublk_device * ub)523 static void ublk_dev_param_discard_apply(struct ublk_device *ub)
524 {
525 struct request_queue *q = ub->ub_disk->queue;
526 const struct ublk_param_discard *p = &ub->params.discard;
527
528 q->limits.discard_alignment = p->discard_alignment;
529 q->limits.discard_granularity = p->discard_granularity;
530 blk_queue_max_discard_sectors(q, p->max_discard_sectors);
531 blk_queue_max_write_zeroes_sectors(q,
532 p->max_write_zeroes_sectors);
533 blk_queue_max_discard_segments(q, p->max_discard_segments);
534 }
535
ublk_validate_params(const struct ublk_device * ub)536 static int ublk_validate_params(const struct ublk_device *ub)
537 {
538 /* basic param is the only one which must be set */
539 if (ub->params.types & UBLK_PARAM_TYPE_BASIC) {
540 const struct ublk_param_basic *p = &ub->params.basic;
541
542 if (p->logical_bs_shift > PAGE_SHIFT || p->logical_bs_shift < 9)
543 return -EINVAL;
544
545 if (p->logical_bs_shift > p->physical_bs_shift)
546 return -EINVAL;
547
548 if (p->max_sectors > (ub->dev_info.max_io_buf_bytes >> 9))
549 return -EINVAL;
550
551 if (ublk_dev_is_zoned(ub) && !p->chunk_sectors)
552 return -EINVAL;
553 } else
554 return -EINVAL;
555
556 if (ub->params.types & UBLK_PARAM_TYPE_DISCARD) {
557 const struct ublk_param_discard *p = &ub->params.discard;
558
559 /* So far, only support single segment discard */
560 if (p->max_discard_sectors && p->max_discard_segments != 1)
561 return -EINVAL;
562
563 if (!p->discard_granularity)
564 return -EINVAL;
565 }
566
567 /* dev_t is read-only */
568 if (ub->params.types & UBLK_PARAM_TYPE_DEVT)
569 return -EINVAL;
570
571 if (ub->params.types & UBLK_PARAM_TYPE_ZONED)
572 return ublk_dev_param_zoned_validate(ub);
573 else if (ublk_dev_is_zoned(ub))
574 return -EINVAL;
575
576 return 0;
577 }
578
ublk_apply_params(struct ublk_device * ub)579 static int ublk_apply_params(struct ublk_device *ub)
580 {
581 if (!(ub->params.types & UBLK_PARAM_TYPE_BASIC))
582 return -EINVAL;
583
584 ublk_dev_param_basic_apply(ub);
585
586 if (ub->params.types & UBLK_PARAM_TYPE_DISCARD)
587 ublk_dev_param_discard_apply(ub);
588
589 if (ub->params.types & UBLK_PARAM_TYPE_ZONED)
590 return ublk_dev_param_zoned_apply(ub);
591
592 return 0;
593 }
594
ublk_support_user_copy(const struct ublk_queue * ubq)595 static inline bool ublk_support_user_copy(const struct ublk_queue *ubq)
596 {
597 return ubq->flags & UBLK_F_USER_COPY;
598 }
599
ublk_need_req_ref(const struct ublk_queue * ubq)600 static inline bool ublk_need_req_ref(const struct ublk_queue *ubq)
601 {
602 /*
603 * read()/write() is involved in user copy, so request reference
604 * has to be grabbed
605 */
606 return ublk_support_user_copy(ubq);
607 }
608
ublk_init_req_ref(const struct ublk_queue * ubq,struct request * req)609 static inline void ublk_init_req_ref(const struct ublk_queue *ubq,
610 struct request *req)
611 {
612 if (ublk_need_req_ref(ubq)) {
613 struct ublk_rq_data *data = blk_mq_rq_to_pdu(req);
614
615 kref_init(&data->ref);
616 }
617 }
618
ublk_get_req_ref(const struct ublk_queue * ubq,struct request * req)619 static inline bool ublk_get_req_ref(const struct ublk_queue *ubq,
620 struct request *req)
621 {
622 if (ublk_need_req_ref(ubq)) {
623 struct ublk_rq_data *data = blk_mq_rq_to_pdu(req);
624
625 return kref_get_unless_zero(&data->ref);
626 }
627
628 return true;
629 }
630
ublk_put_req_ref(const struct ublk_queue * ubq,struct request * req)631 static inline void ublk_put_req_ref(const struct ublk_queue *ubq,
632 struct request *req)
633 {
634 if (ublk_need_req_ref(ubq)) {
635 struct ublk_rq_data *data = blk_mq_rq_to_pdu(req);
636
637 kref_put(&data->ref, ublk_complete_rq);
638 } else {
639 __ublk_complete_rq(req);
640 }
641 }
642
ublk_need_get_data(const struct ublk_queue * ubq)643 static inline bool ublk_need_get_data(const struct ublk_queue *ubq)
644 {
645 return ubq->flags & UBLK_F_NEED_GET_DATA;
646 }
647
ublk_get_device(struct ublk_device * ub)648 static struct ublk_device *ublk_get_device(struct ublk_device *ub)
649 {
650 if (kobject_get_unless_zero(&ub->cdev_dev.kobj))
651 return ub;
652 return NULL;
653 }
654
ublk_put_device(struct ublk_device * ub)655 static void ublk_put_device(struct ublk_device *ub)
656 {
657 put_device(&ub->cdev_dev);
658 }
659
ublk_get_queue(struct ublk_device * dev,int qid)660 static inline struct ublk_queue *ublk_get_queue(struct ublk_device *dev,
661 int qid)
662 {
663 return (struct ublk_queue *)&(dev->__queues[qid * dev->queue_size]);
664 }
665
ublk_rq_has_data(const struct request * rq)666 static inline bool ublk_rq_has_data(const struct request *rq)
667 {
668 return bio_has_data(rq->bio);
669 }
670
ublk_get_iod(struct ublk_queue * ubq,int tag)671 static inline struct ublksrv_io_desc *ublk_get_iod(struct ublk_queue *ubq,
672 int tag)
673 {
674 return (struct ublksrv_io_desc *)
675 &(ubq->io_cmd_buf[tag * sizeof(struct ublksrv_io_desc)]);
676 }
677
ublk_queue_cmd_buf(struct ublk_device * ub,int q_id)678 static inline char *ublk_queue_cmd_buf(struct ublk_device *ub, int q_id)
679 {
680 return ublk_get_queue(ub, q_id)->io_cmd_buf;
681 }
682
ublk_queue_cmd_buf_size(struct ublk_device * ub,int q_id)683 static inline int ublk_queue_cmd_buf_size(struct ublk_device *ub, int q_id)
684 {
685 struct ublk_queue *ubq = ublk_get_queue(ub, q_id);
686
687 return round_up(ubq->q_depth * sizeof(struct ublksrv_io_desc),
688 PAGE_SIZE);
689 }
690
ublk_queue_can_use_recovery_reissue(struct ublk_queue * ubq)691 static inline bool ublk_queue_can_use_recovery_reissue(
692 struct ublk_queue *ubq)
693 {
694 return (ubq->flags & UBLK_F_USER_RECOVERY) &&
695 (ubq->flags & UBLK_F_USER_RECOVERY_REISSUE);
696 }
697
ublk_queue_can_use_recovery(struct ublk_queue * ubq)698 static inline bool ublk_queue_can_use_recovery(
699 struct ublk_queue *ubq)
700 {
701 return ubq->flags & UBLK_F_USER_RECOVERY;
702 }
703
ublk_can_use_recovery(struct ublk_device * ub)704 static inline bool ublk_can_use_recovery(struct ublk_device *ub)
705 {
706 return ub->dev_info.flags & UBLK_F_USER_RECOVERY;
707 }
708
ublk_free_disk(struct gendisk * disk)709 static void ublk_free_disk(struct gendisk *disk)
710 {
711 struct ublk_device *ub = disk->private_data;
712
713 clear_bit(UB_STATE_USED, &ub->state);
714 put_device(&ub->cdev_dev);
715 }
716
ublk_store_owner_uid_gid(unsigned int * owner_uid,unsigned int * owner_gid)717 static void ublk_store_owner_uid_gid(unsigned int *owner_uid,
718 unsigned int *owner_gid)
719 {
720 kuid_t uid;
721 kgid_t gid;
722
723 current_uid_gid(&uid, &gid);
724
725 *owner_uid = from_kuid(&init_user_ns, uid);
726 *owner_gid = from_kgid(&init_user_ns, gid);
727 }
728
ublk_open(struct gendisk * disk,blk_mode_t mode)729 static int ublk_open(struct gendisk *disk, blk_mode_t mode)
730 {
731 struct ublk_device *ub = disk->private_data;
732
733 if (capable(CAP_SYS_ADMIN))
734 return 0;
735
736 /*
737 * If it is one unprivileged device, only owner can open
738 * the disk. Otherwise it could be one trap made by one
739 * evil user who grants this disk's privileges to other
740 * users deliberately.
741 *
742 * This way is reasonable too given anyone can create
743 * unprivileged device, and no need other's grant.
744 */
745 if (ub->dev_info.flags & UBLK_F_UNPRIVILEGED_DEV) {
746 unsigned int curr_uid, curr_gid;
747
748 ublk_store_owner_uid_gid(&curr_uid, &curr_gid);
749
750 if (curr_uid != ub->dev_info.owner_uid || curr_gid !=
751 ub->dev_info.owner_gid)
752 return -EPERM;
753 }
754
755 return 0;
756 }
757
758 static const struct block_device_operations ub_fops = {
759 .owner = THIS_MODULE,
760 .open = ublk_open,
761 .free_disk = ublk_free_disk,
762 .report_zones = ublk_report_zones,
763 };
764
765 #define UBLK_MAX_PIN_PAGES 32
766
767 struct ublk_io_iter {
768 struct page *pages[UBLK_MAX_PIN_PAGES];
769 struct bio *bio;
770 struct bvec_iter iter;
771 };
772
773 /* return how many pages are copied */
ublk_copy_io_pages(struct ublk_io_iter * data,size_t total,size_t pg_off,int dir)774 static void ublk_copy_io_pages(struct ublk_io_iter *data,
775 size_t total, size_t pg_off, int dir)
776 {
777 unsigned done = 0;
778 unsigned pg_idx = 0;
779
780 while (done < total) {
781 struct bio_vec bv = bio_iter_iovec(data->bio, data->iter);
782 unsigned int bytes = min3(bv.bv_len, (unsigned)total - done,
783 (unsigned)(PAGE_SIZE - pg_off));
784 void *bv_buf = bvec_kmap_local(&bv);
785 void *pg_buf = kmap_local_page(data->pages[pg_idx]);
786
787 if (dir == ITER_DEST)
788 memcpy(pg_buf + pg_off, bv_buf, bytes);
789 else
790 memcpy(bv_buf, pg_buf + pg_off, bytes);
791
792 kunmap_local(pg_buf);
793 kunmap_local(bv_buf);
794
795 /* advance page array */
796 pg_off += bytes;
797 if (pg_off == PAGE_SIZE) {
798 pg_idx += 1;
799 pg_off = 0;
800 }
801
802 done += bytes;
803
804 /* advance bio */
805 bio_advance_iter_single(data->bio, &data->iter, bytes);
806 if (!data->iter.bi_size) {
807 data->bio = data->bio->bi_next;
808 if (data->bio == NULL)
809 break;
810 data->iter = data->bio->bi_iter;
811 }
812 }
813 }
814
ublk_advance_io_iter(const struct request * req,struct ublk_io_iter * iter,unsigned int offset)815 static bool ublk_advance_io_iter(const struct request *req,
816 struct ublk_io_iter *iter, unsigned int offset)
817 {
818 struct bio *bio = req->bio;
819
820 for_each_bio(bio) {
821 if (bio->bi_iter.bi_size > offset) {
822 iter->bio = bio;
823 iter->iter = bio->bi_iter;
824 bio_advance_iter(iter->bio, &iter->iter, offset);
825 return true;
826 }
827 offset -= bio->bi_iter.bi_size;
828 }
829 return false;
830 }
831
832 /*
833 * Copy data between request pages and io_iter, and 'offset'
834 * is the start point of linear offset of request.
835 */
ublk_copy_user_pages(const struct request * req,unsigned offset,struct iov_iter * uiter,int dir)836 static size_t ublk_copy_user_pages(const struct request *req,
837 unsigned offset, struct iov_iter *uiter, int dir)
838 {
839 struct ublk_io_iter iter;
840 size_t done = 0;
841
842 if (!ublk_advance_io_iter(req, &iter, offset))
843 return 0;
844
845 while (iov_iter_count(uiter) && iter.bio) {
846 unsigned nr_pages;
847 ssize_t len;
848 size_t off;
849 int i;
850
851 len = iov_iter_get_pages2(uiter, iter.pages,
852 iov_iter_count(uiter),
853 UBLK_MAX_PIN_PAGES, &off);
854 if (len <= 0)
855 return done;
856
857 ublk_copy_io_pages(&iter, len, off, dir);
858 nr_pages = DIV_ROUND_UP(len + off, PAGE_SIZE);
859 for (i = 0; i < nr_pages; i++) {
860 if (dir == ITER_DEST)
861 set_page_dirty(iter.pages[i]);
862 put_page(iter.pages[i]);
863 }
864 done += len;
865 }
866
867 return done;
868 }
869
ublk_need_map_req(const struct request * req)870 static inline bool ublk_need_map_req(const struct request *req)
871 {
872 return ublk_rq_has_data(req) && req_op(req) == REQ_OP_WRITE;
873 }
874
ublk_need_unmap_req(const struct request * req)875 static inline bool ublk_need_unmap_req(const struct request *req)
876 {
877 return ublk_rq_has_data(req) &&
878 (req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN);
879 }
880
ublk_map_io(const struct ublk_queue * ubq,const struct request * req,struct ublk_io * io)881 static int ublk_map_io(const struct ublk_queue *ubq, const struct request *req,
882 struct ublk_io *io)
883 {
884 const unsigned int rq_bytes = blk_rq_bytes(req);
885
886 if (ublk_support_user_copy(ubq))
887 return rq_bytes;
888
889 /*
890 * no zero copy, we delay copy WRITE request data into ublksrv
891 * context and the big benefit is that pinning pages in current
892 * context is pretty fast, see ublk_pin_user_pages
893 */
894 if (ublk_need_map_req(req)) {
895 struct iov_iter iter;
896 const int dir = ITER_DEST;
897
898 import_ubuf(dir, u64_to_user_ptr(io->addr), rq_bytes, &iter);
899 return ublk_copy_user_pages(req, 0, &iter, dir);
900 }
901 return rq_bytes;
902 }
903
ublk_unmap_io(const struct ublk_queue * ubq,const struct request * req,struct ublk_io * io)904 static int ublk_unmap_io(const struct ublk_queue *ubq,
905 const struct request *req,
906 struct ublk_io *io)
907 {
908 const unsigned int rq_bytes = blk_rq_bytes(req);
909
910 if (ublk_support_user_copy(ubq))
911 return rq_bytes;
912
913 if (ublk_need_unmap_req(req)) {
914 struct iov_iter iter;
915 const int dir = ITER_SOURCE;
916
917 WARN_ON_ONCE(io->res > rq_bytes);
918
919 import_ubuf(dir, u64_to_user_ptr(io->addr), io->res, &iter);
920 return ublk_copy_user_pages(req, 0, &iter, dir);
921 }
922 return rq_bytes;
923 }
924
ublk_req_build_flags(struct request * req)925 static inline unsigned int ublk_req_build_flags(struct request *req)
926 {
927 unsigned flags = 0;
928
929 if (req->cmd_flags & REQ_FAILFAST_DEV)
930 flags |= UBLK_IO_F_FAILFAST_DEV;
931
932 if (req->cmd_flags & REQ_FAILFAST_TRANSPORT)
933 flags |= UBLK_IO_F_FAILFAST_TRANSPORT;
934
935 if (req->cmd_flags & REQ_FAILFAST_DRIVER)
936 flags |= UBLK_IO_F_FAILFAST_DRIVER;
937
938 if (req->cmd_flags & REQ_META)
939 flags |= UBLK_IO_F_META;
940
941 if (req->cmd_flags & REQ_FUA)
942 flags |= UBLK_IO_F_FUA;
943
944 if (req->cmd_flags & REQ_NOUNMAP)
945 flags |= UBLK_IO_F_NOUNMAP;
946
947 if (req->cmd_flags & REQ_SWAP)
948 flags |= UBLK_IO_F_SWAP;
949
950 return flags;
951 }
952
ublk_setup_iod(struct ublk_queue * ubq,struct request * req)953 static blk_status_t ublk_setup_iod(struct ublk_queue *ubq, struct request *req)
954 {
955 struct ublksrv_io_desc *iod = ublk_get_iod(ubq, req->tag);
956 struct ublk_io *io = &ubq->ios[req->tag];
957 enum req_op op = req_op(req);
958 u32 ublk_op;
959
960 if (!ublk_queue_is_zoned(ubq) &&
961 (op_is_zone_mgmt(op) || op == REQ_OP_ZONE_APPEND))
962 return BLK_STS_IOERR;
963
964 switch (req_op(req)) {
965 case REQ_OP_READ:
966 ublk_op = UBLK_IO_OP_READ;
967 break;
968 case REQ_OP_WRITE:
969 ublk_op = UBLK_IO_OP_WRITE;
970 break;
971 case REQ_OP_FLUSH:
972 ublk_op = UBLK_IO_OP_FLUSH;
973 break;
974 case REQ_OP_DISCARD:
975 ublk_op = UBLK_IO_OP_DISCARD;
976 break;
977 case REQ_OP_WRITE_ZEROES:
978 ublk_op = UBLK_IO_OP_WRITE_ZEROES;
979 break;
980 default:
981 if (ublk_queue_is_zoned(ubq))
982 return ublk_setup_iod_zoned(ubq, req);
983 return BLK_STS_IOERR;
984 }
985
986 /* need to translate since kernel may change */
987 iod->op_flags = ublk_op | ublk_req_build_flags(req);
988 iod->nr_sectors = blk_rq_sectors(req);
989 iod->start_sector = blk_rq_pos(req);
990 iod->addr = io->addr;
991
992 return BLK_STS_OK;
993 }
994
ublk_get_uring_cmd_pdu(struct io_uring_cmd * ioucmd)995 static inline struct ublk_uring_cmd_pdu *ublk_get_uring_cmd_pdu(
996 struct io_uring_cmd *ioucmd)
997 {
998 return (struct ublk_uring_cmd_pdu *)&ioucmd->pdu;
999 }
1000
ubq_daemon_is_dying(struct ublk_queue * ubq)1001 static inline bool ubq_daemon_is_dying(struct ublk_queue *ubq)
1002 {
1003 return ubq->ubq_daemon->flags & PF_EXITING;
1004 }
1005
1006 /* todo: handle partial completion */
__ublk_complete_rq(struct request * req)1007 static inline void __ublk_complete_rq(struct request *req)
1008 {
1009 struct ublk_queue *ubq = req->mq_hctx->driver_data;
1010 struct ublk_io *io = &ubq->ios[req->tag];
1011 unsigned int unmapped_bytes;
1012 blk_status_t res = BLK_STS_OK;
1013
1014 /* called from ublk_abort_queue() code path */
1015 if (io->flags & UBLK_IO_FLAG_ABORTED) {
1016 res = BLK_STS_IOERR;
1017 goto exit;
1018 }
1019
1020 /* failed read IO if nothing is read */
1021 if (!io->res && req_op(req) == REQ_OP_READ)
1022 io->res = -EIO;
1023
1024 if (io->res < 0) {
1025 res = errno_to_blk_status(io->res);
1026 goto exit;
1027 }
1028
1029 /*
1030 * FLUSH, DISCARD or WRITE_ZEROES usually won't return bytes returned, so end them
1031 * directly.
1032 *
1033 * Both the two needn't unmap.
1034 */
1035 if (req_op(req) != REQ_OP_READ && req_op(req) != REQ_OP_WRITE &&
1036 req_op(req) != REQ_OP_DRV_IN)
1037 goto exit;
1038
1039 /* for READ request, writing data in iod->addr to rq buffers */
1040 unmapped_bytes = ublk_unmap_io(ubq, req, io);
1041
1042 /*
1043 * Extremely impossible since we got data filled in just before
1044 *
1045 * Re-read simply for this unlikely case.
1046 */
1047 if (unlikely(unmapped_bytes < io->res))
1048 io->res = unmapped_bytes;
1049
1050 if (blk_update_request(req, BLK_STS_OK, io->res))
1051 blk_mq_requeue_request(req, true);
1052 else
1053 __blk_mq_end_request(req, BLK_STS_OK);
1054
1055 return;
1056 exit:
1057 blk_mq_end_request(req, res);
1058 }
1059
ublk_complete_rq(struct kref * ref)1060 static void ublk_complete_rq(struct kref *ref)
1061 {
1062 struct ublk_rq_data *data = container_of(ref, struct ublk_rq_data,
1063 ref);
1064 struct request *req = blk_mq_rq_from_pdu(data);
1065
1066 __ublk_complete_rq(req);
1067 }
1068
1069 /*
1070 * Since __ublk_rq_task_work always fails requests immediately during
1071 * exiting, __ublk_fail_req() is only called from abort context during
1072 * exiting. So lock is unnecessary.
1073 *
1074 * Also aborting may not be started yet, keep in mind that one failed
1075 * request may be issued by block layer again.
1076 */
__ublk_fail_req(struct ublk_queue * ubq,struct ublk_io * io,struct request * req)1077 static void __ublk_fail_req(struct ublk_queue *ubq, struct ublk_io *io,
1078 struct request *req)
1079 {
1080 WARN_ON_ONCE(io->flags & UBLK_IO_FLAG_ACTIVE);
1081
1082 if (ublk_queue_can_use_recovery_reissue(ubq))
1083 blk_mq_requeue_request(req, false);
1084 else
1085 ublk_put_req_ref(ubq, req);
1086 }
1087
ubq_complete_io_cmd(struct ublk_io * io,int res,unsigned issue_flags)1088 static void ubq_complete_io_cmd(struct ublk_io *io, int res,
1089 unsigned issue_flags)
1090 {
1091 /* mark this cmd owned by ublksrv */
1092 io->flags |= UBLK_IO_FLAG_OWNED_BY_SRV;
1093
1094 /*
1095 * clear ACTIVE since we are done with this sqe/cmd slot
1096 * We can only accept io cmd in case of being not active.
1097 */
1098 io->flags &= ~UBLK_IO_FLAG_ACTIVE;
1099
1100 /* tell ublksrv one io request is coming */
1101 io_uring_cmd_done(io->cmd, res, 0, issue_flags);
1102 }
1103
1104 #define UBLK_REQUEUE_DELAY_MS 3
1105
__ublk_abort_rq(struct ublk_queue * ubq,struct request * rq)1106 static inline void __ublk_abort_rq(struct ublk_queue *ubq,
1107 struct request *rq)
1108 {
1109 /* We cannot process this rq so just requeue it. */
1110 if (ublk_queue_can_use_recovery(ubq))
1111 blk_mq_requeue_request(rq, false);
1112 else
1113 blk_mq_end_request(rq, BLK_STS_IOERR);
1114 }
1115
__ublk_rq_task_work(struct request * req,unsigned issue_flags)1116 static inline void __ublk_rq_task_work(struct request *req,
1117 unsigned issue_flags)
1118 {
1119 struct ublk_queue *ubq = req->mq_hctx->driver_data;
1120 int tag = req->tag;
1121 struct ublk_io *io = &ubq->ios[tag];
1122 unsigned int mapped_bytes;
1123
1124 pr_devel("%s: complete: op %d, qid %d tag %d io_flags %x addr %llx\n",
1125 __func__, io->cmd->cmd_op, ubq->q_id, req->tag, io->flags,
1126 ublk_get_iod(ubq, req->tag)->addr);
1127
1128 /*
1129 * Task is exiting if either:
1130 *
1131 * (1) current != ubq_daemon.
1132 * io_uring_cmd_complete_in_task() tries to run task_work
1133 * in a workqueue if ubq_daemon(cmd's task) is PF_EXITING.
1134 *
1135 * (2) current->flags & PF_EXITING.
1136 */
1137 if (unlikely(current != ubq->ubq_daemon || current->flags & PF_EXITING)) {
1138 __ublk_abort_rq(ubq, req);
1139 return;
1140 }
1141
1142 if (ublk_need_get_data(ubq) && ublk_need_map_req(req)) {
1143 /*
1144 * We have not handled UBLK_IO_NEED_GET_DATA command yet,
1145 * so immepdately pass UBLK_IO_RES_NEED_GET_DATA to ublksrv
1146 * and notify it.
1147 */
1148 if (!(io->flags & UBLK_IO_FLAG_NEED_GET_DATA)) {
1149 io->flags |= UBLK_IO_FLAG_NEED_GET_DATA;
1150 pr_devel("%s: need get data. op %d, qid %d tag %d io_flags %x\n",
1151 __func__, io->cmd->cmd_op, ubq->q_id,
1152 req->tag, io->flags);
1153 ubq_complete_io_cmd(io, UBLK_IO_RES_NEED_GET_DATA, issue_flags);
1154 return;
1155 }
1156 /*
1157 * We have handled UBLK_IO_NEED_GET_DATA command,
1158 * so clear UBLK_IO_FLAG_NEED_GET_DATA now and just
1159 * do the copy work.
1160 */
1161 io->flags &= ~UBLK_IO_FLAG_NEED_GET_DATA;
1162 /* update iod->addr because ublksrv may have passed a new io buffer */
1163 ublk_get_iod(ubq, req->tag)->addr = io->addr;
1164 pr_devel("%s: update iod->addr: op %d, qid %d tag %d io_flags %x addr %llx\n",
1165 __func__, io->cmd->cmd_op, ubq->q_id, req->tag, io->flags,
1166 ublk_get_iod(ubq, req->tag)->addr);
1167 }
1168
1169 mapped_bytes = ublk_map_io(ubq, req, io);
1170
1171 /* partially mapped, update io descriptor */
1172 if (unlikely(mapped_bytes != blk_rq_bytes(req))) {
1173 /*
1174 * Nothing mapped, retry until we succeed.
1175 *
1176 * We may never succeed in mapping any bytes here because
1177 * of OOM. TODO: reserve one buffer with single page pinned
1178 * for providing forward progress guarantee.
1179 */
1180 if (unlikely(!mapped_bytes)) {
1181 blk_mq_requeue_request(req, false);
1182 blk_mq_delay_kick_requeue_list(req->q,
1183 UBLK_REQUEUE_DELAY_MS);
1184 return;
1185 }
1186
1187 ublk_get_iod(ubq, req->tag)->nr_sectors =
1188 mapped_bytes >> 9;
1189 }
1190
1191 ublk_init_req_ref(ubq, req);
1192 ubq_complete_io_cmd(io, UBLK_IO_RES_OK, issue_flags);
1193 }
1194
ublk_forward_io_cmds(struct ublk_queue * ubq,unsigned issue_flags)1195 static inline void ublk_forward_io_cmds(struct ublk_queue *ubq,
1196 unsigned issue_flags)
1197 {
1198 struct llist_node *io_cmds = llist_del_all(&ubq->io_cmds);
1199 struct ublk_rq_data *data, *tmp;
1200
1201 io_cmds = llist_reverse_order(io_cmds);
1202 llist_for_each_entry_safe(data, tmp, io_cmds, node)
1203 __ublk_rq_task_work(blk_mq_rq_from_pdu(data), issue_flags);
1204 }
1205
ublk_rq_task_work_cb(struct io_uring_cmd * cmd,unsigned issue_flags)1206 static void ublk_rq_task_work_cb(struct io_uring_cmd *cmd, unsigned issue_flags)
1207 {
1208 struct ublk_uring_cmd_pdu *pdu = ublk_get_uring_cmd_pdu(cmd);
1209 struct ublk_queue *ubq = pdu->ubq;
1210
1211 ublk_forward_io_cmds(ubq, issue_flags);
1212 }
1213
ublk_queue_cmd(struct ublk_queue * ubq,struct request * rq)1214 static void ublk_queue_cmd(struct ublk_queue *ubq, struct request *rq)
1215 {
1216 struct ublk_rq_data *data = blk_mq_rq_to_pdu(rq);
1217
1218 if (llist_add(&data->node, &ubq->io_cmds)) {
1219 struct ublk_io *io = &ubq->ios[rq->tag];
1220
1221 io_uring_cmd_complete_in_task(io->cmd, ublk_rq_task_work_cb);
1222 }
1223 }
1224
ublk_timeout(struct request * rq)1225 static enum blk_eh_timer_return ublk_timeout(struct request *rq)
1226 {
1227 struct ublk_queue *ubq = rq->mq_hctx->driver_data;
1228 unsigned int nr_inflight = 0;
1229 int i;
1230
1231 if (ubq->flags & UBLK_F_UNPRIVILEGED_DEV) {
1232 if (!ubq->timeout) {
1233 send_sig(SIGKILL, ubq->ubq_daemon, 0);
1234 ubq->timeout = true;
1235 }
1236
1237 return BLK_EH_DONE;
1238 }
1239
1240 if (!ubq_daemon_is_dying(ubq))
1241 return BLK_EH_RESET_TIMER;
1242
1243 for (i = 0; i < ubq->q_depth; i++) {
1244 struct ublk_io *io = &ubq->ios[i];
1245
1246 if (!(io->flags & UBLK_IO_FLAG_ACTIVE))
1247 nr_inflight++;
1248 }
1249
1250 /* cancelable uring_cmd can't help us if all commands are in-flight */
1251 if (nr_inflight == ubq->q_depth) {
1252 struct ublk_device *ub = ubq->dev;
1253
1254 if (ublk_abort_requests(ub, ubq)) {
1255 if (ublk_can_use_recovery(ub))
1256 schedule_work(&ub->quiesce_work);
1257 else
1258 schedule_work(&ub->stop_work);
1259 }
1260 return BLK_EH_DONE;
1261 }
1262
1263 return BLK_EH_RESET_TIMER;
1264 }
1265
ublk_queue_rq(struct blk_mq_hw_ctx * hctx,const struct blk_mq_queue_data * bd)1266 static blk_status_t ublk_queue_rq(struct blk_mq_hw_ctx *hctx,
1267 const struct blk_mq_queue_data *bd)
1268 {
1269 struct ublk_queue *ubq = hctx->driver_data;
1270 struct request *rq = bd->rq;
1271 blk_status_t res;
1272
1273 /* fill iod to slot in io cmd buffer */
1274 res = ublk_setup_iod(ubq, rq);
1275 if (unlikely(res != BLK_STS_OK))
1276 return BLK_STS_IOERR;
1277
1278 /* With recovery feature enabled, force_abort is set in
1279 * ublk_stop_dev() before calling del_gendisk(). We have to
1280 * abort all requeued and new rqs here to let del_gendisk()
1281 * move on. Besides, we cannot not call io_uring_cmd_complete_in_task()
1282 * to avoid UAF on io_uring ctx.
1283 *
1284 * Note: force_abort is guaranteed to be seen because it is set
1285 * before request queue is unqiuesced.
1286 */
1287 if (ublk_queue_can_use_recovery(ubq) && unlikely(ubq->force_abort))
1288 return BLK_STS_IOERR;
1289
1290 if (unlikely(ubq->canceling)) {
1291 __ublk_abort_rq(ubq, rq);
1292 return BLK_STS_OK;
1293 }
1294
1295 blk_mq_start_request(bd->rq);
1296 ublk_queue_cmd(ubq, rq);
1297
1298 return BLK_STS_OK;
1299 }
1300
ublk_init_hctx(struct blk_mq_hw_ctx * hctx,void * driver_data,unsigned int hctx_idx)1301 static int ublk_init_hctx(struct blk_mq_hw_ctx *hctx, void *driver_data,
1302 unsigned int hctx_idx)
1303 {
1304 struct ublk_device *ub = driver_data;
1305 struct ublk_queue *ubq = ublk_get_queue(ub, hctx->queue_num);
1306
1307 hctx->driver_data = ubq;
1308 return 0;
1309 }
1310
1311 static const struct blk_mq_ops ublk_mq_ops = {
1312 .queue_rq = ublk_queue_rq,
1313 .init_hctx = ublk_init_hctx,
1314 .timeout = ublk_timeout,
1315 };
1316
ublk_ch_open(struct inode * inode,struct file * filp)1317 static int ublk_ch_open(struct inode *inode, struct file *filp)
1318 {
1319 struct ublk_device *ub = container_of(inode->i_cdev,
1320 struct ublk_device, cdev);
1321
1322 if (test_and_set_bit(UB_STATE_OPEN, &ub->state))
1323 return -EBUSY;
1324 filp->private_data = ub;
1325 return 0;
1326 }
1327
ublk_ch_release(struct inode * inode,struct file * filp)1328 static int ublk_ch_release(struct inode *inode, struct file *filp)
1329 {
1330 struct ublk_device *ub = filp->private_data;
1331
1332 clear_bit(UB_STATE_OPEN, &ub->state);
1333 return 0;
1334 }
1335
1336 /* map pre-allocated per-queue cmd buffer to ublksrv daemon */
ublk_ch_mmap(struct file * filp,struct vm_area_struct * vma)1337 static int ublk_ch_mmap(struct file *filp, struct vm_area_struct *vma)
1338 {
1339 struct ublk_device *ub = filp->private_data;
1340 size_t sz = vma->vm_end - vma->vm_start;
1341 unsigned max_sz = UBLK_MAX_QUEUE_DEPTH * sizeof(struct ublksrv_io_desc);
1342 unsigned long pfn, end, phys_off = vma->vm_pgoff << PAGE_SHIFT;
1343 int q_id, ret = 0;
1344
1345 spin_lock(&ub->lock);
1346 if (!ub->mm)
1347 ub->mm = current->mm;
1348 if (current->mm != ub->mm)
1349 ret = -EINVAL;
1350 spin_unlock(&ub->lock);
1351
1352 if (ret)
1353 return ret;
1354
1355 if (vma->vm_flags & VM_WRITE)
1356 return -EPERM;
1357
1358 end = UBLKSRV_CMD_BUF_OFFSET + ub->dev_info.nr_hw_queues * max_sz;
1359 if (phys_off < UBLKSRV_CMD_BUF_OFFSET || phys_off >= end)
1360 return -EINVAL;
1361
1362 q_id = (phys_off - UBLKSRV_CMD_BUF_OFFSET) / max_sz;
1363 pr_devel("%s: qid %d, pid %d, addr %lx pg_off %lx sz %lu\n",
1364 __func__, q_id, current->pid, vma->vm_start,
1365 phys_off, (unsigned long)sz);
1366
1367 if (sz != ublk_queue_cmd_buf_size(ub, q_id))
1368 return -EINVAL;
1369
1370 pfn = virt_to_phys(ublk_queue_cmd_buf(ub, q_id)) >> PAGE_SHIFT;
1371 return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot);
1372 }
1373
ublk_commit_completion(struct ublk_device * ub,const struct ublksrv_io_cmd * ub_cmd)1374 static void ublk_commit_completion(struct ublk_device *ub,
1375 const struct ublksrv_io_cmd *ub_cmd)
1376 {
1377 u32 qid = ub_cmd->q_id, tag = ub_cmd->tag;
1378 struct ublk_queue *ubq = ublk_get_queue(ub, qid);
1379 struct ublk_io *io = &ubq->ios[tag];
1380 struct request *req;
1381
1382 /* now this cmd slot is owned by nbd driver */
1383 io->flags &= ~UBLK_IO_FLAG_OWNED_BY_SRV;
1384 io->res = ub_cmd->result;
1385
1386 /* find the io request and complete */
1387 req = blk_mq_tag_to_rq(ub->tag_set.tags[qid], tag);
1388 if (WARN_ON_ONCE(unlikely(!req)))
1389 return;
1390
1391 if (req_op(req) == REQ_OP_ZONE_APPEND)
1392 req->__sector = ub_cmd->zone_append_lba;
1393
1394 if (likely(!blk_should_fake_timeout(req->q)))
1395 ublk_put_req_ref(ubq, req);
1396 }
1397
1398 /*
1399 * Called from ubq_daemon context via cancel fn, meantime quiesce ublk
1400 * blk-mq queue, so we are called exclusively with blk-mq and ubq_daemon
1401 * context, so everything is serialized.
1402 */
ublk_abort_queue(struct ublk_device * ub,struct ublk_queue * ubq)1403 static void ublk_abort_queue(struct ublk_device *ub, struct ublk_queue *ubq)
1404 {
1405 int i;
1406
1407 for (i = 0; i < ubq->q_depth; i++) {
1408 struct ublk_io *io = &ubq->ios[i];
1409
1410 if (!(io->flags & UBLK_IO_FLAG_ACTIVE)) {
1411 struct request *rq;
1412
1413 /*
1414 * Either we fail the request or ublk_rq_task_work_fn
1415 * will do it
1416 */
1417 rq = blk_mq_tag_to_rq(ub->tag_set.tags[ubq->q_id], i);
1418 if (rq && blk_mq_request_started(rq)) {
1419 io->flags |= UBLK_IO_FLAG_ABORTED;
1420 __ublk_fail_req(ubq, io, rq);
1421 }
1422 }
1423 }
1424 }
1425
ublk_abort_requests(struct ublk_device * ub,struct ublk_queue * ubq)1426 static bool ublk_abort_requests(struct ublk_device *ub, struct ublk_queue *ubq)
1427 {
1428 struct gendisk *disk;
1429
1430 spin_lock(&ubq->cancel_lock);
1431 if (ubq->canceling) {
1432 spin_unlock(&ubq->cancel_lock);
1433 return false;
1434 }
1435 ubq->canceling = true;
1436 spin_unlock(&ubq->cancel_lock);
1437
1438 spin_lock(&ub->lock);
1439 disk = ub->ub_disk;
1440 if (disk)
1441 get_device(disk_to_dev(disk));
1442 spin_unlock(&ub->lock);
1443
1444 /* Our disk has been dead */
1445 if (!disk)
1446 return false;
1447
1448 /* Now we are serialized with ublk_queue_rq() */
1449 blk_mq_quiesce_queue(disk->queue);
1450 /* abort queue is for making forward progress */
1451 ublk_abort_queue(ub, ubq);
1452 blk_mq_unquiesce_queue(disk->queue);
1453 put_device(disk_to_dev(disk));
1454
1455 return true;
1456 }
1457
ublk_cancel_cmd(struct ublk_queue * ubq,struct ublk_io * io,unsigned int issue_flags)1458 static void ublk_cancel_cmd(struct ublk_queue *ubq, struct ublk_io *io,
1459 unsigned int issue_flags)
1460 {
1461 bool done;
1462
1463 if (!(io->flags & UBLK_IO_FLAG_ACTIVE))
1464 return;
1465
1466 spin_lock(&ubq->cancel_lock);
1467 done = !!(io->flags & UBLK_IO_FLAG_CANCELED);
1468 if (!done)
1469 io->flags |= UBLK_IO_FLAG_CANCELED;
1470 spin_unlock(&ubq->cancel_lock);
1471
1472 if (!done)
1473 io_uring_cmd_done(io->cmd, UBLK_IO_RES_ABORT, 0, issue_flags);
1474 }
1475
1476 /*
1477 * The ublk char device won't be closed when calling cancel fn, so both
1478 * ublk device and queue are guaranteed to be live
1479 */
ublk_uring_cmd_cancel_fn(struct io_uring_cmd * cmd,unsigned int issue_flags)1480 static void ublk_uring_cmd_cancel_fn(struct io_uring_cmd *cmd,
1481 unsigned int issue_flags)
1482 {
1483 struct ublk_uring_cmd_pdu *pdu = ublk_get_uring_cmd_pdu(cmd);
1484 struct ublk_queue *ubq = pdu->ubq;
1485 struct task_struct *task;
1486 struct ublk_device *ub;
1487 bool need_schedule;
1488 struct ublk_io *io;
1489
1490 if (WARN_ON_ONCE(!ubq))
1491 return;
1492
1493 if (WARN_ON_ONCE(pdu->tag >= ubq->q_depth))
1494 return;
1495
1496 task = io_uring_cmd_get_task(cmd);
1497 if (WARN_ON_ONCE(task && task != ubq->ubq_daemon))
1498 return;
1499
1500 ub = ubq->dev;
1501 need_schedule = ublk_abort_requests(ub, ubq);
1502
1503 io = &ubq->ios[pdu->tag];
1504 WARN_ON_ONCE(io->cmd != cmd);
1505 ublk_cancel_cmd(ubq, io, issue_flags);
1506
1507 if (need_schedule) {
1508 if (ublk_can_use_recovery(ub))
1509 schedule_work(&ub->quiesce_work);
1510 else
1511 schedule_work(&ub->stop_work);
1512 }
1513 }
1514
ublk_queue_ready(struct ublk_queue * ubq)1515 static inline bool ublk_queue_ready(struct ublk_queue *ubq)
1516 {
1517 return ubq->nr_io_ready == ubq->q_depth;
1518 }
1519
ublk_cancel_queue(struct ublk_queue * ubq)1520 static void ublk_cancel_queue(struct ublk_queue *ubq)
1521 {
1522 int i;
1523
1524 for (i = 0; i < ubq->q_depth; i++)
1525 ublk_cancel_cmd(ubq, &ubq->ios[i], IO_URING_F_UNLOCKED);
1526 }
1527
1528 /* Cancel all pending commands, must be called after del_gendisk() returns */
ublk_cancel_dev(struct ublk_device * ub)1529 static void ublk_cancel_dev(struct ublk_device *ub)
1530 {
1531 int i;
1532
1533 for (i = 0; i < ub->dev_info.nr_hw_queues; i++)
1534 ublk_cancel_queue(ublk_get_queue(ub, i));
1535 }
1536
ublk_check_inflight_rq(struct request * rq,void * data)1537 static bool ublk_check_inflight_rq(struct request *rq, void *data)
1538 {
1539 bool *idle = data;
1540
1541 if (blk_mq_request_started(rq)) {
1542 *idle = false;
1543 return false;
1544 }
1545 return true;
1546 }
1547
ublk_wait_tagset_rqs_idle(struct ublk_device * ub)1548 static void ublk_wait_tagset_rqs_idle(struct ublk_device *ub)
1549 {
1550 bool idle;
1551
1552 WARN_ON_ONCE(!blk_queue_quiesced(ub->ub_disk->queue));
1553 while (true) {
1554 idle = true;
1555 blk_mq_tagset_busy_iter(&ub->tag_set,
1556 ublk_check_inflight_rq, &idle);
1557 if (idle)
1558 break;
1559 msleep(UBLK_REQUEUE_DELAY_MS);
1560 }
1561 }
1562
__ublk_quiesce_dev(struct ublk_device * ub)1563 static void __ublk_quiesce_dev(struct ublk_device *ub)
1564 {
1565 pr_devel("%s: quiesce ub: dev_id %d state %s\n",
1566 __func__, ub->dev_info.dev_id,
1567 ub->dev_info.state == UBLK_S_DEV_LIVE ?
1568 "LIVE" : "QUIESCED");
1569 blk_mq_quiesce_queue(ub->ub_disk->queue);
1570 ublk_wait_tagset_rqs_idle(ub);
1571 ub->dev_info.state = UBLK_S_DEV_QUIESCED;
1572 }
1573
ublk_quiesce_work_fn(struct work_struct * work)1574 static void ublk_quiesce_work_fn(struct work_struct *work)
1575 {
1576 struct ublk_device *ub =
1577 container_of(work, struct ublk_device, quiesce_work);
1578
1579 mutex_lock(&ub->mutex);
1580 if (ub->dev_info.state != UBLK_S_DEV_LIVE)
1581 goto unlock;
1582 __ublk_quiesce_dev(ub);
1583 unlock:
1584 mutex_unlock(&ub->mutex);
1585 ublk_cancel_dev(ub);
1586 }
1587
ublk_unquiesce_dev(struct ublk_device * ub)1588 static void ublk_unquiesce_dev(struct ublk_device *ub)
1589 {
1590 int i;
1591
1592 pr_devel("%s: unquiesce ub: dev_id %d state %s\n",
1593 __func__, ub->dev_info.dev_id,
1594 ub->dev_info.state == UBLK_S_DEV_LIVE ?
1595 "LIVE" : "QUIESCED");
1596 /* quiesce_work has run. We let requeued rqs be aborted
1597 * before running fallback_wq. "force_abort" must be seen
1598 * after request queue is unqiuesced. Then del_gendisk()
1599 * can move on.
1600 */
1601 for (i = 0; i < ub->dev_info.nr_hw_queues; i++)
1602 ublk_get_queue(ub, i)->force_abort = true;
1603
1604 blk_mq_unquiesce_queue(ub->ub_disk->queue);
1605 /* We may have requeued some rqs in ublk_quiesce_queue() */
1606 blk_mq_kick_requeue_list(ub->ub_disk->queue);
1607 }
1608
ublk_stop_dev(struct ublk_device * ub)1609 static void ublk_stop_dev(struct ublk_device *ub)
1610 {
1611 struct gendisk *disk;
1612
1613 mutex_lock(&ub->mutex);
1614 if (ub->dev_info.state == UBLK_S_DEV_DEAD)
1615 goto unlock;
1616 if (ublk_can_use_recovery(ub)) {
1617 if (ub->dev_info.state == UBLK_S_DEV_LIVE)
1618 __ublk_quiesce_dev(ub);
1619 ublk_unquiesce_dev(ub);
1620 }
1621 del_gendisk(ub->ub_disk);
1622
1623 /* Sync with ublk_abort_queue() by holding the lock */
1624 spin_lock(&ub->lock);
1625 disk = ub->ub_disk;
1626 ub->dev_info.state = UBLK_S_DEV_DEAD;
1627 ub->dev_info.ublksrv_pid = -1;
1628 ub->ub_disk = NULL;
1629 spin_unlock(&ub->lock);
1630 put_disk(disk);
1631 unlock:
1632 mutex_unlock(&ub->mutex);
1633 ublk_cancel_dev(ub);
1634 }
1635
1636 /* device can only be started after all IOs are ready */
ublk_mark_io_ready(struct ublk_device * ub,struct ublk_queue * ubq)1637 static void ublk_mark_io_ready(struct ublk_device *ub, struct ublk_queue *ubq)
1638 {
1639 mutex_lock(&ub->mutex);
1640 ubq->nr_io_ready++;
1641 if (ublk_queue_ready(ubq)) {
1642 ubq->ubq_daemon = current;
1643 get_task_struct(ubq->ubq_daemon);
1644 ub->nr_queues_ready++;
1645
1646 if (capable(CAP_SYS_ADMIN))
1647 ub->nr_privileged_daemon++;
1648 }
1649 if (ub->nr_queues_ready == ub->dev_info.nr_hw_queues)
1650 complete_all(&ub->completion);
1651 mutex_unlock(&ub->mutex);
1652 }
1653
ublk_handle_need_get_data(struct ublk_device * ub,int q_id,int tag)1654 static void ublk_handle_need_get_data(struct ublk_device *ub, int q_id,
1655 int tag)
1656 {
1657 struct ublk_queue *ubq = ublk_get_queue(ub, q_id);
1658 struct request *req = blk_mq_tag_to_rq(ub->tag_set.tags[q_id], tag);
1659
1660 ublk_queue_cmd(ubq, req);
1661 }
1662
ublk_check_cmd_op(u32 cmd_op)1663 static inline int ublk_check_cmd_op(u32 cmd_op)
1664 {
1665 u32 ioc_type = _IOC_TYPE(cmd_op);
1666
1667 if (!IS_ENABLED(CONFIG_BLKDEV_UBLK_LEGACY_OPCODES) && ioc_type != 'u')
1668 return -EOPNOTSUPP;
1669
1670 if (ioc_type != 'u' && ioc_type != 0)
1671 return -EOPNOTSUPP;
1672
1673 return 0;
1674 }
1675
ublk_fill_io_cmd(struct ublk_io * io,struct io_uring_cmd * cmd,unsigned long buf_addr)1676 static inline void ublk_fill_io_cmd(struct ublk_io *io,
1677 struct io_uring_cmd *cmd, unsigned long buf_addr)
1678 {
1679 io->cmd = cmd;
1680 io->flags |= UBLK_IO_FLAG_ACTIVE;
1681 io->addr = buf_addr;
1682 }
1683
ublk_prep_cancel(struct io_uring_cmd * cmd,unsigned int issue_flags,struct ublk_queue * ubq,unsigned int tag)1684 static inline void ublk_prep_cancel(struct io_uring_cmd *cmd,
1685 unsigned int issue_flags,
1686 struct ublk_queue *ubq, unsigned int tag)
1687 {
1688 struct ublk_uring_cmd_pdu *pdu = ublk_get_uring_cmd_pdu(cmd);
1689
1690 /*
1691 * Safe to refer to @ubq since ublk_queue won't be died until its
1692 * commands are completed
1693 */
1694 pdu->ubq = ubq;
1695 pdu->tag = tag;
1696 io_uring_cmd_mark_cancelable(cmd, issue_flags);
1697 }
1698
__ublk_ch_uring_cmd(struct io_uring_cmd * cmd,unsigned int issue_flags,const struct ublksrv_io_cmd * ub_cmd)1699 static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
1700 unsigned int issue_flags,
1701 const struct ublksrv_io_cmd *ub_cmd)
1702 {
1703 struct ublk_device *ub = cmd->file->private_data;
1704 struct ublk_queue *ubq;
1705 struct ublk_io *io;
1706 u32 cmd_op = cmd->cmd_op;
1707 unsigned tag = ub_cmd->tag;
1708 int ret = -EINVAL;
1709 struct request *req;
1710
1711 pr_devel("%s: received: cmd op %d queue %d tag %d result %d\n",
1712 __func__, cmd->cmd_op, ub_cmd->q_id, tag,
1713 ub_cmd->result);
1714
1715 if (ub_cmd->q_id >= ub->dev_info.nr_hw_queues)
1716 goto out;
1717
1718 ubq = ublk_get_queue(ub, ub_cmd->q_id);
1719 if (!ubq || ub_cmd->q_id != ubq->q_id)
1720 goto out;
1721
1722 if (ubq->ubq_daemon && ubq->ubq_daemon != current)
1723 goto out;
1724
1725 if (tag >= ubq->q_depth)
1726 goto out;
1727
1728 io = &ubq->ios[tag];
1729
1730 /* there is pending io cmd, something must be wrong */
1731 if (io->flags & UBLK_IO_FLAG_ACTIVE) {
1732 ret = -EBUSY;
1733 goto out;
1734 }
1735
1736 /*
1737 * ensure that the user issues UBLK_IO_NEED_GET_DATA
1738 * iff the driver have set the UBLK_IO_FLAG_NEED_GET_DATA.
1739 */
1740 if ((!!(io->flags & UBLK_IO_FLAG_NEED_GET_DATA))
1741 ^ (_IOC_NR(cmd_op) == UBLK_IO_NEED_GET_DATA))
1742 goto out;
1743
1744 ret = ublk_check_cmd_op(cmd_op);
1745 if (ret)
1746 goto out;
1747
1748 ret = -EINVAL;
1749 switch (_IOC_NR(cmd_op)) {
1750 case UBLK_IO_FETCH_REQ:
1751 /* UBLK_IO_FETCH_REQ is only allowed before queue is setup */
1752 if (ublk_queue_ready(ubq)) {
1753 ret = -EBUSY;
1754 goto out;
1755 }
1756 /*
1757 * The io is being handled by server, so COMMIT_RQ is expected
1758 * instead of FETCH_REQ
1759 */
1760 if (io->flags & UBLK_IO_FLAG_OWNED_BY_SRV)
1761 goto out;
1762
1763 if (!ublk_support_user_copy(ubq)) {
1764 /*
1765 * FETCH_RQ has to provide IO buffer if NEED GET
1766 * DATA is not enabled
1767 */
1768 if (!ub_cmd->addr && !ublk_need_get_data(ubq))
1769 goto out;
1770 } else if (ub_cmd->addr) {
1771 /* User copy requires addr to be unset */
1772 ret = -EINVAL;
1773 goto out;
1774 }
1775
1776 ublk_fill_io_cmd(io, cmd, ub_cmd->addr);
1777 ublk_mark_io_ready(ub, ubq);
1778 break;
1779 case UBLK_IO_COMMIT_AND_FETCH_REQ:
1780 req = blk_mq_tag_to_rq(ub->tag_set.tags[ub_cmd->q_id], tag);
1781
1782 if (!(io->flags & UBLK_IO_FLAG_OWNED_BY_SRV))
1783 goto out;
1784
1785 if (!ublk_support_user_copy(ubq)) {
1786 /*
1787 * COMMIT_AND_FETCH_REQ has to provide IO buffer if
1788 * NEED GET DATA is not enabled or it is Read IO.
1789 */
1790 if (!ub_cmd->addr && (!ublk_need_get_data(ubq) ||
1791 req_op(req) == REQ_OP_READ))
1792 goto out;
1793 } else if (req_op(req) != REQ_OP_ZONE_APPEND && ub_cmd->addr) {
1794 /*
1795 * User copy requires addr to be unset when command is
1796 * not zone append
1797 */
1798 ret = -EINVAL;
1799 goto out;
1800 }
1801
1802 ublk_fill_io_cmd(io, cmd, ub_cmd->addr);
1803 ublk_commit_completion(ub, ub_cmd);
1804 break;
1805 case UBLK_IO_NEED_GET_DATA:
1806 if (!(io->flags & UBLK_IO_FLAG_OWNED_BY_SRV))
1807 goto out;
1808 ublk_fill_io_cmd(io, cmd, ub_cmd->addr);
1809 ublk_handle_need_get_data(ub, ub_cmd->q_id, ub_cmd->tag);
1810 break;
1811 default:
1812 goto out;
1813 }
1814 ublk_prep_cancel(cmd, issue_flags, ubq, tag);
1815 return -EIOCBQUEUED;
1816
1817 out:
1818 io_uring_cmd_done(cmd, ret, 0, issue_flags);
1819 pr_devel("%s: complete: cmd op %d, tag %d ret %x io_flags %x\n",
1820 __func__, cmd_op, tag, ret, io->flags);
1821 return -EIOCBQUEUED;
1822 }
1823
__ublk_check_and_get_req(struct ublk_device * ub,struct ublk_queue * ubq,int tag,size_t offset)1824 static inline struct request *__ublk_check_and_get_req(struct ublk_device *ub,
1825 struct ublk_queue *ubq, int tag, size_t offset)
1826 {
1827 struct request *req;
1828
1829 if (!ublk_need_req_ref(ubq))
1830 return NULL;
1831
1832 req = blk_mq_tag_to_rq(ub->tag_set.tags[ubq->q_id], tag);
1833 if (!req)
1834 return NULL;
1835
1836 if (!ublk_get_req_ref(ubq, req))
1837 return NULL;
1838
1839 if (unlikely(!blk_mq_request_started(req) || req->tag != tag))
1840 goto fail_put;
1841
1842 if (!ublk_rq_has_data(req))
1843 goto fail_put;
1844
1845 if (offset > blk_rq_bytes(req))
1846 goto fail_put;
1847
1848 return req;
1849 fail_put:
1850 ublk_put_req_ref(ubq, req);
1851 return NULL;
1852 }
1853
ublk_ch_uring_cmd_local(struct io_uring_cmd * cmd,unsigned int issue_flags)1854 static inline int ublk_ch_uring_cmd_local(struct io_uring_cmd *cmd,
1855 unsigned int issue_flags)
1856 {
1857 /*
1858 * Not necessary for async retry, but let's keep it simple and always
1859 * copy the values to avoid any potential reuse.
1860 */
1861 const struct ublksrv_io_cmd *ub_src = io_uring_sqe_cmd(cmd->sqe);
1862 const struct ublksrv_io_cmd ub_cmd = {
1863 .q_id = READ_ONCE(ub_src->q_id),
1864 .tag = READ_ONCE(ub_src->tag),
1865 .result = READ_ONCE(ub_src->result),
1866 .addr = READ_ONCE(ub_src->addr)
1867 };
1868
1869 WARN_ON_ONCE(issue_flags & IO_URING_F_UNLOCKED);
1870
1871 return __ublk_ch_uring_cmd(cmd, issue_flags, &ub_cmd);
1872 }
1873
ublk_ch_uring_cmd_cb(struct io_uring_cmd * cmd,unsigned int issue_flags)1874 static void ublk_ch_uring_cmd_cb(struct io_uring_cmd *cmd,
1875 unsigned int issue_flags)
1876 {
1877 ublk_ch_uring_cmd_local(cmd, issue_flags);
1878 }
1879
ublk_ch_uring_cmd(struct io_uring_cmd * cmd,unsigned int issue_flags)1880 static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags)
1881 {
1882 if (unlikely(issue_flags & IO_URING_F_CANCEL)) {
1883 ublk_uring_cmd_cancel_fn(cmd, issue_flags);
1884 return 0;
1885 }
1886
1887 /* well-implemented server won't run into unlocked */
1888 if (unlikely(issue_flags & IO_URING_F_UNLOCKED)) {
1889 io_uring_cmd_complete_in_task(cmd, ublk_ch_uring_cmd_cb);
1890 return -EIOCBQUEUED;
1891 }
1892
1893 return ublk_ch_uring_cmd_local(cmd, issue_flags);
1894 }
1895
ublk_check_ubuf_dir(const struct request * req,int ubuf_dir)1896 static inline bool ublk_check_ubuf_dir(const struct request *req,
1897 int ubuf_dir)
1898 {
1899 /* copy ubuf to request pages */
1900 if ((req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN) &&
1901 ubuf_dir == ITER_SOURCE)
1902 return true;
1903
1904 /* copy request pages to ubuf */
1905 if ((req_op(req) == REQ_OP_WRITE ||
1906 req_op(req) == REQ_OP_ZONE_APPEND) &&
1907 ubuf_dir == ITER_DEST)
1908 return true;
1909
1910 return false;
1911 }
1912
ublk_check_and_get_req(struct kiocb * iocb,struct iov_iter * iter,size_t * off,int dir)1913 static struct request *ublk_check_and_get_req(struct kiocb *iocb,
1914 struct iov_iter *iter, size_t *off, int dir)
1915 {
1916 struct ublk_device *ub = iocb->ki_filp->private_data;
1917 struct ublk_queue *ubq;
1918 struct request *req;
1919 size_t buf_off;
1920 u16 tag, q_id;
1921
1922 if (!ub)
1923 return ERR_PTR(-EACCES);
1924
1925 if (!user_backed_iter(iter))
1926 return ERR_PTR(-EACCES);
1927
1928 if (ub->dev_info.state == UBLK_S_DEV_DEAD)
1929 return ERR_PTR(-EACCES);
1930
1931 tag = ublk_pos_to_tag(iocb->ki_pos);
1932 q_id = ublk_pos_to_hwq(iocb->ki_pos);
1933 buf_off = ublk_pos_to_buf_off(iocb->ki_pos);
1934
1935 if (q_id >= ub->dev_info.nr_hw_queues)
1936 return ERR_PTR(-EINVAL);
1937
1938 ubq = ublk_get_queue(ub, q_id);
1939 if (!ubq)
1940 return ERR_PTR(-EINVAL);
1941
1942 if (tag >= ubq->q_depth)
1943 return ERR_PTR(-EINVAL);
1944
1945 req = __ublk_check_and_get_req(ub, ubq, tag, buf_off);
1946 if (!req)
1947 return ERR_PTR(-EINVAL);
1948
1949 if (!req->mq_hctx || !req->mq_hctx->driver_data)
1950 goto fail;
1951
1952 if (!ublk_check_ubuf_dir(req, dir))
1953 goto fail;
1954
1955 *off = buf_off;
1956 return req;
1957 fail:
1958 ublk_put_req_ref(ubq, req);
1959 return ERR_PTR(-EACCES);
1960 }
1961
ublk_ch_read_iter(struct kiocb * iocb,struct iov_iter * to)1962 static ssize_t ublk_ch_read_iter(struct kiocb *iocb, struct iov_iter *to)
1963 {
1964 struct ublk_queue *ubq;
1965 struct request *req;
1966 size_t buf_off;
1967 size_t ret;
1968
1969 req = ublk_check_and_get_req(iocb, to, &buf_off, ITER_DEST);
1970 if (IS_ERR(req))
1971 return PTR_ERR(req);
1972
1973 ret = ublk_copy_user_pages(req, buf_off, to, ITER_DEST);
1974 ubq = req->mq_hctx->driver_data;
1975 ublk_put_req_ref(ubq, req);
1976
1977 return ret;
1978 }
1979
ublk_ch_write_iter(struct kiocb * iocb,struct iov_iter * from)1980 static ssize_t ublk_ch_write_iter(struct kiocb *iocb, struct iov_iter *from)
1981 {
1982 struct ublk_queue *ubq;
1983 struct request *req;
1984 size_t buf_off;
1985 size_t ret;
1986
1987 req = ublk_check_and_get_req(iocb, from, &buf_off, ITER_SOURCE);
1988 if (IS_ERR(req))
1989 return PTR_ERR(req);
1990
1991 ret = ublk_copy_user_pages(req, buf_off, from, ITER_SOURCE);
1992 ubq = req->mq_hctx->driver_data;
1993 ublk_put_req_ref(ubq, req);
1994
1995 return ret;
1996 }
1997
1998 static const struct file_operations ublk_ch_fops = {
1999 .owner = THIS_MODULE,
2000 .open = ublk_ch_open,
2001 .release = ublk_ch_release,
2002 .llseek = no_llseek,
2003 .read_iter = ublk_ch_read_iter,
2004 .write_iter = ublk_ch_write_iter,
2005 .uring_cmd = ublk_ch_uring_cmd,
2006 .mmap = ublk_ch_mmap,
2007 };
2008
ublk_deinit_queue(struct ublk_device * ub,int q_id)2009 static void ublk_deinit_queue(struct ublk_device *ub, int q_id)
2010 {
2011 int size = ublk_queue_cmd_buf_size(ub, q_id);
2012 struct ublk_queue *ubq = ublk_get_queue(ub, q_id);
2013
2014 if (ubq->ubq_daemon)
2015 put_task_struct(ubq->ubq_daemon);
2016 if (ubq->io_cmd_buf)
2017 free_pages((unsigned long)ubq->io_cmd_buf, get_order(size));
2018 }
2019
ublk_init_queue(struct ublk_device * ub,int q_id)2020 static int ublk_init_queue(struct ublk_device *ub, int q_id)
2021 {
2022 struct ublk_queue *ubq = ublk_get_queue(ub, q_id);
2023 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO;
2024 void *ptr;
2025 int size;
2026
2027 spin_lock_init(&ubq->cancel_lock);
2028 ubq->flags = ub->dev_info.flags;
2029 ubq->q_id = q_id;
2030 ubq->q_depth = ub->dev_info.queue_depth;
2031 size = ublk_queue_cmd_buf_size(ub, q_id);
2032
2033 ptr = (void *) __get_free_pages(gfp_flags, get_order(size));
2034 if (!ptr)
2035 return -ENOMEM;
2036
2037 ubq->io_cmd_buf = ptr;
2038 ubq->dev = ub;
2039 return 0;
2040 }
2041
ublk_deinit_queues(struct ublk_device * ub)2042 static void ublk_deinit_queues(struct ublk_device *ub)
2043 {
2044 int nr_queues = ub->dev_info.nr_hw_queues;
2045 int i;
2046
2047 if (!ub->__queues)
2048 return;
2049
2050 for (i = 0; i < nr_queues; i++)
2051 ublk_deinit_queue(ub, i);
2052 kfree(ub->__queues);
2053 }
2054
ublk_init_queues(struct ublk_device * ub)2055 static int ublk_init_queues(struct ublk_device *ub)
2056 {
2057 int nr_queues = ub->dev_info.nr_hw_queues;
2058 int depth = ub->dev_info.queue_depth;
2059 int ubq_size = sizeof(struct ublk_queue) + depth * sizeof(struct ublk_io);
2060 int i, ret = -ENOMEM;
2061
2062 ub->queue_size = ubq_size;
2063 ub->__queues = kcalloc(nr_queues, ubq_size, GFP_KERNEL);
2064 if (!ub->__queues)
2065 return ret;
2066
2067 for (i = 0; i < nr_queues; i++) {
2068 if (ublk_init_queue(ub, i))
2069 goto fail;
2070 }
2071
2072 init_completion(&ub->completion);
2073 return 0;
2074
2075 fail:
2076 ublk_deinit_queues(ub);
2077 return ret;
2078 }
2079
ublk_alloc_dev_number(struct ublk_device * ub,int idx)2080 static int ublk_alloc_dev_number(struct ublk_device *ub, int idx)
2081 {
2082 int i = idx;
2083 int err;
2084
2085 spin_lock(&ublk_idr_lock);
2086 /* allocate id, if @id >= 0, we're requesting that specific id */
2087 if (i >= 0) {
2088 err = idr_alloc(&ublk_index_idr, ub, i, i + 1, GFP_NOWAIT);
2089 if (err == -ENOSPC)
2090 err = -EEXIST;
2091 } else {
2092 err = idr_alloc(&ublk_index_idr, ub, 0, UBLK_MAX_UBLKS,
2093 GFP_NOWAIT);
2094 }
2095 spin_unlock(&ublk_idr_lock);
2096
2097 if (err >= 0)
2098 ub->ub_number = err;
2099
2100 return err;
2101 }
2102
ublk_free_dev_number(struct ublk_device * ub)2103 static void ublk_free_dev_number(struct ublk_device *ub)
2104 {
2105 spin_lock(&ublk_idr_lock);
2106 idr_remove(&ublk_index_idr, ub->ub_number);
2107 wake_up_all(&ublk_idr_wq);
2108 spin_unlock(&ublk_idr_lock);
2109 }
2110
ublk_cdev_rel(struct device * dev)2111 static void ublk_cdev_rel(struct device *dev)
2112 {
2113 struct ublk_device *ub = container_of(dev, struct ublk_device, cdev_dev);
2114
2115 blk_mq_free_tag_set(&ub->tag_set);
2116 ublk_deinit_queues(ub);
2117 ublk_free_dev_number(ub);
2118 mutex_destroy(&ub->mutex);
2119 kfree(ub);
2120 }
2121
ublk_add_chdev(struct ublk_device * ub)2122 static int ublk_add_chdev(struct ublk_device *ub)
2123 {
2124 struct device *dev = &ub->cdev_dev;
2125 int minor = ub->ub_number;
2126 int ret;
2127
2128 dev->parent = ublk_misc.this_device;
2129 dev->devt = MKDEV(MAJOR(ublk_chr_devt), minor);
2130 dev->class = &ublk_chr_class;
2131 dev->release = ublk_cdev_rel;
2132 device_initialize(dev);
2133
2134 ret = dev_set_name(dev, "ublkc%d", minor);
2135 if (ret)
2136 goto fail;
2137
2138 cdev_init(&ub->cdev, &ublk_ch_fops);
2139 ret = cdev_device_add(&ub->cdev, dev);
2140 if (ret)
2141 goto fail;
2142
2143 ublks_added++;
2144 return 0;
2145 fail:
2146 put_device(dev);
2147 return ret;
2148 }
2149
ublk_stop_work_fn(struct work_struct * work)2150 static void ublk_stop_work_fn(struct work_struct *work)
2151 {
2152 struct ublk_device *ub =
2153 container_of(work, struct ublk_device, stop_work);
2154
2155 ublk_stop_dev(ub);
2156 }
2157
2158 /* align max io buffer size with PAGE_SIZE */
ublk_align_max_io_size(struct ublk_device * ub)2159 static void ublk_align_max_io_size(struct ublk_device *ub)
2160 {
2161 unsigned int max_io_bytes = ub->dev_info.max_io_buf_bytes;
2162
2163 ub->dev_info.max_io_buf_bytes =
2164 round_down(max_io_bytes, PAGE_SIZE);
2165 }
2166
ublk_add_tag_set(struct ublk_device * ub)2167 static int ublk_add_tag_set(struct ublk_device *ub)
2168 {
2169 ub->tag_set.ops = &ublk_mq_ops;
2170 ub->tag_set.nr_hw_queues = ub->dev_info.nr_hw_queues;
2171 ub->tag_set.queue_depth = ub->dev_info.queue_depth;
2172 ub->tag_set.numa_node = NUMA_NO_NODE;
2173 ub->tag_set.cmd_size = sizeof(struct ublk_rq_data);
2174 ub->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
2175 ub->tag_set.driver_data = ub;
2176 return blk_mq_alloc_tag_set(&ub->tag_set);
2177 }
2178
ublk_remove(struct ublk_device * ub)2179 static void ublk_remove(struct ublk_device *ub)
2180 {
2181 ublk_stop_dev(ub);
2182 cancel_work_sync(&ub->stop_work);
2183 cancel_work_sync(&ub->quiesce_work);
2184 cdev_device_del(&ub->cdev, &ub->cdev_dev);
2185 put_device(&ub->cdev_dev);
2186 ublks_added--;
2187 }
2188
ublk_get_device_from_id(int idx)2189 static struct ublk_device *ublk_get_device_from_id(int idx)
2190 {
2191 struct ublk_device *ub = NULL;
2192
2193 if (idx < 0)
2194 return NULL;
2195
2196 spin_lock(&ublk_idr_lock);
2197 ub = idr_find(&ublk_index_idr, idx);
2198 if (ub)
2199 ub = ublk_get_device(ub);
2200 spin_unlock(&ublk_idr_lock);
2201
2202 return ub;
2203 }
2204
ublk_ctrl_start_dev(struct ublk_device * ub,struct io_uring_cmd * cmd)2205 static int ublk_ctrl_start_dev(struct ublk_device *ub, struct io_uring_cmd *cmd)
2206 {
2207 const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
2208 int ublksrv_pid = (int)header->data[0];
2209 struct gendisk *disk;
2210 int ret = -EINVAL;
2211
2212 if (ublksrv_pid <= 0)
2213 return -EINVAL;
2214
2215 if (wait_for_completion_interruptible(&ub->completion) != 0)
2216 return -EINTR;
2217
2218 mutex_lock(&ub->mutex);
2219 if (ub->dev_info.state == UBLK_S_DEV_LIVE ||
2220 test_bit(UB_STATE_USED, &ub->state)) {
2221 ret = -EEXIST;
2222 goto out_unlock;
2223 }
2224
2225 disk = blk_mq_alloc_disk(&ub->tag_set, NULL);
2226 if (IS_ERR(disk)) {
2227 ret = PTR_ERR(disk);
2228 goto out_unlock;
2229 }
2230 sprintf(disk->disk_name, "ublkb%d", ub->ub_number);
2231 disk->fops = &ub_fops;
2232 disk->private_data = ub;
2233
2234 ub->dev_info.ublksrv_pid = ublksrv_pid;
2235 ub->ub_disk = disk;
2236
2237 ret = ublk_apply_params(ub);
2238 if (ret)
2239 goto out_put_disk;
2240
2241 /* don't probe partitions if any one ubq daemon is un-trusted */
2242 if (ub->nr_privileged_daemon != ub->nr_queues_ready)
2243 set_bit(GD_SUPPRESS_PART_SCAN, &disk->state);
2244
2245 get_device(&ub->cdev_dev);
2246 ub->dev_info.state = UBLK_S_DEV_LIVE;
2247
2248 if (ublk_dev_is_zoned(ub)) {
2249 ret = ublk_revalidate_disk_zones(ub);
2250 if (ret)
2251 goto out_put_cdev;
2252 }
2253
2254 ret = add_disk(disk);
2255 if (ret)
2256 goto out_put_cdev;
2257
2258 set_bit(UB_STATE_USED, &ub->state);
2259
2260 out_put_cdev:
2261 if (ret) {
2262 ub->dev_info.state = UBLK_S_DEV_DEAD;
2263 ublk_put_device(ub);
2264 }
2265 out_put_disk:
2266 if (ret)
2267 put_disk(disk);
2268 out_unlock:
2269 mutex_unlock(&ub->mutex);
2270 return ret;
2271 }
2272
ublk_ctrl_get_queue_affinity(struct ublk_device * ub,struct io_uring_cmd * cmd)2273 static int ublk_ctrl_get_queue_affinity(struct ublk_device *ub,
2274 struct io_uring_cmd *cmd)
2275 {
2276 const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
2277 void __user *argp = (void __user *)(unsigned long)header->addr;
2278 cpumask_var_t cpumask;
2279 unsigned long queue;
2280 unsigned int retlen;
2281 unsigned int i;
2282 int ret;
2283
2284 if (header->len * BITS_PER_BYTE < nr_cpu_ids)
2285 return -EINVAL;
2286 if (header->len & (sizeof(unsigned long)-1))
2287 return -EINVAL;
2288 if (!header->addr)
2289 return -EINVAL;
2290
2291 queue = header->data[0];
2292 if (queue >= ub->dev_info.nr_hw_queues)
2293 return -EINVAL;
2294
2295 if (!zalloc_cpumask_var(&cpumask, GFP_KERNEL))
2296 return -ENOMEM;
2297
2298 for_each_possible_cpu(i) {
2299 if (ub->tag_set.map[HCTX_TYPE_DEFAULT].mq_map[i] == queue)
2300 cpumask_set_cpu(i, cpumask);
2301 }
2302
2303 ret = -EFAULT;
2304 retlen = min_t(unsigned short, header->len, cpumask_size());
2305 if (copy_to_user(argp, cpumask, retlen))
2306 goto out_free_cpumask;
2307 if (retlen != header->len &&
2308 clear_user(argp + retlen, header->len - retlen))
2309 goto out_free_cpumask;
2310
2311 ret = 0;
2312 out_free_cpumask:
2313 free_cpumask_var(cpumask);
2314 return ret;
2315 }
2316
ublk_dump_dev_info(struct ublksrv_ctrl_dev_info * info)2317 static inline void ublk_dump_dev_info(struct ublksrv_ctrl_dev_info *info)
2318 {
2319 pr_devel("%s: dev id %d flags %llx\n", __func__,
2320 info->dev_id, info->flags);
2321 pr_devel("\t nr_hw_queues %d queue_depth %d\n",
2322 info->nr_hw_queues, info->queue_depth);
2323 }
2324
ublk_ctrl_add_dev(struct io_uring_cmd * cmd)2325 static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd)
2326 {
2327 const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
2328 void __user *argp = (void __user *)(unsigned long)header->addr;
2329 struct ublksrv_ctrl_dev_info info;
2330 struct ublk_device *ub;
2331 int ret = -EINVAL;
2332
2333 if (header->len < sizeof(info) || !header->addr)
2334 return -EINVAL;
2335 if (header->queue_id != (u16)-1) {
2336 pr_warn("%s: queue_id is wrong %x\n",
2337 __func__, header->queue_id);
2338 return -EINVAL;
2339 }
2340
2341 if (copy_from_user(&info, argp, sizeof(info)))
2342 return -EFAULT;
2343
2344 if (capable(CAP_SYS_ADMIN))
2345 info.flags &= ~UBLK_F_UNPRIVILEGED_DEV;
2346 else if (!(info.flags & UBLK_F_UNPRIVILEGED_DEV))
2347 return -EPERM;
2348
2349 /*
2350 * unprivileged device can't be trusted, but RECOVERY and
2351 * RECOVERY_REISSUE still may hang error handling, so can't
2352 * support recovery features for unprivileged ublk now
2353 *
2354 * TODO: provide forward progress for RECOVERY handler, so that
2355 * unprivileged device can benefit from it
2356 */
2357 if (info.flags & UBLK_F_UNPRIVILEGED_DEV)
2358 info.flags &= ~(UBLK_F_USER_RECOVERY_REISSUE |
2359 UBLK_F_USER_RECOVERY);
2360
2361 /* the created device is always owned by current user */
2362 ublk_store_owner_uid_gid(&info.owner_uid, &info.owner_gid);
2363
2364 if (header->dev_id != info.dev_id) {
2365 pr_warn("%s: dev id not match %u %u\n",
2366 __func__, header->dev_id, info.dev_id);
2367 return -EINVAL;
2368 }
2369
2370 if (header->dev_id != U32_MAX && header->dev_id >= UBLK_MAX_UBLKS) {
2371 pr_warn("%s: dev id is too large. Max supported is %d\n",
2372 __func__, UBLK_MAX_UBLKS - 1);
2373 return -EINVAL;
2374 }
2375
2376 ublk_dump_dev_info(&info);
2377
2378 ret = mutex_lock_killable(&ublk_ctl_mutex);
2379 if (ret)
2380 return ret;
2381
2382 ret = -EACCES;
2383 if (ublks_added >= ublks_max)
2384 goto out_unlock;
2385
2386 ret = -ENOMEM;
2387 ub = kzalloc(sizeof(*ub), GFP_KERNEL);
2388 if (!ub)
2389 goto out_unlock;
2390 mutex_init(&ub->mutex);
2391 spin_lock_init(&ub->lock);
2392 INIT_WORK(&ub->quiesce_work, ublk_quiesce_work_fn);
2393 INIT_WORK(&ub->stop_work, ublk_stop_work_fn);
2394
2395 ret = ublk_alloc_dev_number(ub, header->dev_id);
2396 if (ret < 0)
2397 goto out_free_ub;
2398
2399 memcpy(&ub->dev_info, &info, sizeof(info));
2400
2401 /* update device id */
2402 ub->dev_info.dev_id = ub->ub_number;
2403
2404 /*
2405 * 64bit flags will be copied back to userspace as feature
2406 * negotiation result, so have to clear flags which driver
2407 * doesn't support yet, then userspace can get correct flags
2408 * (features) to handle.
2409 */
2410 ub->dev_info.flags &= UBLK_F_ALL;
2411
2412 ub->dev_info.flags |= UBLK_F_CMD_IOCTL_ENCODE |
2413 UBLK_F_URING_CMD_COMP_IN_TASK;
2414
2415 /* GET_DATA isn't needed any more with USER_COPY */
2416 if (ublk_dev_is_user_copy(ub))
2417 ub->dev_info.flags &= ~UBLK_F_NEED_GET_DATA;
2418
2419 /* Zoned storage support requires user copy feature */
2420 if (ublk_dev_is_zoned(ub) &&
2421 (!IS_ENABLED(CONFIG_BLK_DEV_ZONED) || !ublk_dev_is_user_copy(ub))) {
2422 ret = -EINVAL;
2423 goto out_free_dev_number;
2424 }
2425
2426 /* We are not ready to support zero copy */
2427 ub->dev_info.flags &= ~UBLK_F_SUPPORT_ZERO_COPY;
2428
2429 ub->dev_info.nr_hw_queues = min_t(unsigned int,
2430 ub->dev_info.nr_hw_queues, nr_cpu_ids);
2431 ublk_align_max_io_size(ub);
2432
2433 ret = ublk_init_queues(ub);
2434 if (ret)
2435 goto out_free_dev_number;
2436
2437 ret = ublk_add_tag_set(ub);
2438 if (ret)
2439 goto out_deinit_queues;
2440
2441 ret = -EFAULT;
2442 if (copy_to_user(argp, &ub->dev_info, sizeof(info)))
2443 goto out_free_tag_set;
2444
2445 /*
2446 * Add the char dev so that ublksrv daemon can be setup.
2447 * ublk_add_chdev() will cleanup everything if it fails.
2448 */
2449 ret = ublk_add_chdev(ub);
2450 goto out_unlock;
2451
2452 out_free_tag_set:
2453 blk_mq_free_tag_set(&ub->tag_set);
2454 out_deinit_queues:
2455 ublk_deinit_queues(ub);
2456 out_free_dev_number:
2457 ublk_free_dev_number(ub);
2458 out_free_ub:
2459 mutex_destroy(&ub->mutex);
2460 kfree(ub);
2461 out_unlock:
2462 mutex_unlock(&ublk_ctl_mutex);
2463 return ret;
2464 }
2465
ublk_idr_freed(int id)2466 static inline bool ublk_idr_freed(int id)
2467 {
2468 void *ptr;
2469
2470 spin_lock(&ublk_idr_lock);
2471 ptr = idr_find(&ublk_index_idr, id);
2472 spin_unlock(&ublk_idr_lock);
2473
2474 return ptr == NULL;
2475 }
2476
ublk_ctrl_del_dev(struct ublk_device ** p_ub)2477 static int ublk_ctrl_del_dev(struct ublk_device **p_ub)
2478 {
2479 struct ublk_device *ub = *p_ub;
2480 int idx = ub->ub_number;
2481 int ret;
2482
2483 ret = mutex_lock_killable(&ublk_ctl_mutex);
2484 if (ret)
2485 return ret;
2486
2487 if (!test_bit(UB_STATE_DELETED, &ub->state)) {
2488 ublk_remove(ub);
2489 set_bit(UB_STATE_DELETED, &ub->state);
2490 }
2491
2492 /* Mark the reference as consumed */
2493 *p_ub = NULL;
2494 ublk_put_device(ub);
2495 mutex_unlock(&ublk_ctl_mutex);
2496
2497 /*
2498 * Wait until the idr is removed, then it can be reused after
2499 * DEL_DEV command is returned.
2500 *
2501 * If we returns because of user interrupt, future delete command
2502 * may come:
2503 *
2504 * - the device number isn't freed, this device won't or needn't
2505 * be deleted again, since UB_STATE_DELETED is set, and device
2506 * will be released after the last reference is dropped
2507 *
2508 * - the device number is freed already, we will not find this
2509 * device via ublk_get_device_from_id()
2510 */
2511 if (wait_event_interruptible(ublk_idr_wq, ublk_idr_freed(idx)))
2512 return -EINTR;
2513 return 0;
2514 }
2515
ublk_ctrl_cmd_dump(struct io_uring_cmd * cmd)2516 static inline void ublk_ctrl_cmd_dump(struct io_uring_cmd *cmd)
2517 {
2518 const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
2519
2520 pr_devel("%s: cmd_op %x, dev id %d qid %d data %llx buf %llx len %u\n",
2521 __func__, cmd->cmd_op, header->dev_id, header->queue_id,
2522 header->data[0], header->addr, header->len);
2523 }
2524
ublk_ctrl_stop_dev(struct ublk_device * ub)2525 static int ublk_ctrl_stop_dev(struct ublk_device *ub)
2526 {
2527 ublk_stop_dev(ub);
2528 cancel_work_sync(&ub->stop_work);
2529 cancel_work_sync(&ub->quiesce_work);
2530
2531 return 0;
2532 }
2533
ublk_ctrl_get_dev_info(struct ublk_device * ub,struct io_uring_cmd * cmd)2534 static int ublk_ctrl_get_dev_info(struct ublk_device *ub,
2535 struct io_uring_cmd *cmd)
2536 {
2537 const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
2538 void __user *argp = (void __user *)(unsigned long)header->addr;
2539
2540 if (header->len < sizeof(struct ublksrv_ctrl_dev_info) || !header->addr)
2541 return -EINVAL;
2542
2543 if (copy_to_user(argp, &ub->dev_info, sizeof(ub->dev_info)))
2544 return -EFAULT;
2545
2546 return 0;
2547 }
2548
2549 /* TYPE_DEVT is readonly, so fill it up before returning to userspace */
ublk_ctrl_fill_params_devt(struct ublk_device * ub)2550 static void ublk_ctrl_fill_params_devt(struct ublk_device *ub)
2551 {
2552 ub->params.devt.char_major = MAJOR(ub->cdev_dev.devt);
2553 ub->params.devt.char_minor = MINOR(ub->cdev_dev.devt);
2554
2555 if (ub->ub_disk) {
2556 ub->params.devt.disk_major = MAJOR(disk_devt(ub->ub_disk));
2557 ub->params.devt.disk_minor = MINOR(disk_devt(ub->ub_disk));
2558 } else {
2559 ub->params.devt.disk_major = 0;
2560 ub->params.devt.disk_minor = 0;
2561 }
2562 ub->params.types |= UBLK_PARAM_TYPE_DEVT;
2563 }
2564
ublk_ctrl_get_params(struct ublk_device * ub,struct io_uring_cmd * cmd)2565 static int ublk_ctrl_get_params(struct ublk_device *ub,
2566 struct io_uring_cmd *cmd)
2567 {
2568 const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
2569 void __user *argp = (void __user *)(unsigned long)header->addr;
2570 struct ublk_params_header ph;
2571 int ret;
2572
2573 if (header->len <= sizeof(ph) || !header->addr)
2574 return -EINVAL;
2575
2576 if (copy_from_user(&ph, argp, sizeof(ph)))
2577 return -EFAULT;
2578
2579 if (ph.len > header->len || !ph.len)
2580 return -EINVAL;
2581
2582 if (ph.len > sizeof(struct ublk_params))
2583 ph.len = sizeof(struct ublk_params);
2584
2585 mutex_lock(&ub->mutex);
2586 ublk_ctrl_fill_params_devt(ub);
2587 if (copy_to_user(argp, &ub->params, ph.len))
2588 ret = -EFAULT;
2589 else
2590 ret = 0;
2591 mutex_unlock(&ub->mutex);
2592
2593 return ret;
2594 }
2595
ublk_ctrl_set_params(struct ublk_device * ub,struct io_uring_cmd * cmd)2596 static int ublk_ctrl_set_params(struct ublk_device *ub,
2597 struct io_uring_cmd *cmd)
2598 {
2599 const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
2600 void __user *argp = (void __user *)(unsigned long)header->addr;
2601 struct ublk_params_header ph;
2602 int ret = -EFAULT;
2603
2604 if (header->len <= sizeof(ph) || !header->addr)
2605 return -EINVAL;
2606
2607 if (copy_from_user(&ph, argp, sizeof(ph)))
2608 return -EFAULT;
2609
2610 if (ph.len > header->len || !ph.len || !ph.types)
2611 return -EINVAL;
2612
2613 if (ph.len > sizeof(struct ublk_params))
2614 ph.len = sizeof(struct ublk_params);
2615
2616 /* parameters can only be changed when device isn't live */
2617 mutex_lock(&ub->mutex);
2618 if (ub->dev_info.state == UBLK_S_DEV_LIVE) {
2619 ret = -EACCES;
2620 } else if (copy_from_user(&ub->params, argp, ph.len)) {
2621 ret = -EFAULT;
2622 } else {
2623 /* clear all we don't support yet */
2624 ub->params.types &= UBLK_PARAM_TYPE_ALL;
2625 ret = ublk_validate_params(ub);
2626 if (ret)
2627 ub->params.types = 0;
2628 }
2629 mutex_unlock(&ub->mutex);
2630
2631 return ret;
2632 }
2633
ublk_queue_reinit(struct ublk_device * ub,struct ublk_queue * ubq)2634 static void ublk_queue_reinit(struct ublk_device *ub, struct ublk_queue *ubq)
2635 {
2636 int i;
2637
2638 WARN_ON_ONCE(!(ubq->ubq_daemon && ubq_daemon_is_dying(ubq)));
2639
2640 /* All old ioucmds have to be completed */
2641 ubq->nr_io_ready = 0;
2642 /* old daemon is PF_EXITING, put it now */
2643 put_task_struct(ubq->ubq_daemon);
2644 /* We have to reset it to NULL, otherwise ub won't accept new FETCH_REQ */
2645 ubq->ubq_daemon = NULL;
2646 ubq->timeout = false;
2647 ubq->canceling = false;
2648
2649 for (i = 0; i < ubq->q_depth; i++) {
2650 struct ublk_io *io = &ubq->ios[i];
2651
2652 /* forget everything now and be ready for new FETCH_REQ */
2653 io->flags = 0;
2654 io->cmd = NULL;
2655 io->addr = 0;
2656 }
2657 }
2658
ublk_ctrl_start_recovery(struct ublk_device * ub,struct io_uring_cmd * cmd)2659 static int ublk_ctrl_start_recovery(struct ublk_device *ub,
2660 struct io_uring_cmd *cmd)
2661 {
2662 const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
2663 int ret = -EINVAL;
2664 int i;
2665
2666 mutex_lock(&ub->mutex);
2667 if (!ublk_can_use_recovery(ub))
2668 goto out_unlock;
2669 /*
2670 * START_RECOVERY is only allowd after:
2671 *
2672 * (1) UB_STATE_OPEN is not set, which means the dying process is exited
2673 * and related io_uring ctx is freed so file struct of /dev/ublkcX is
2674 * released.
2675 *
2676 * (2) UBLK_S_DEV_QUIESCED is set, which means the quiesce_work:
2677 * (a)has quiesced request queue
2678 * (b)has requeued every inflight rqs whose io_flags is ACTIVE
2679 * (c)has requeued/aborted every inflight rqs whose io_flags is NOT ACTIVE
2680 * (d)has completed/camceled all ioucmds owned by ther dying process
2681 */
2682 if (test_bit(UB_STATE_OPEN, &ub->state) ||
2683 ub->dev_info.state != UBLK_S_DEV_QUIESCED) {
2684 ret = -EBUSY;
2685 goto out_unlock;
2686 }
2687 pr_devel("%s: start recovery for dev id %d.\n", __func__, header->dev_id);
2688 for (i = 0; i < ub->dev_info.nr_hw_queues; i++)
2689 ublk_queue_reinit(ub, ublk_get_queue(ub, i));
2690 /* set to NULL, otherwise new ubq_daemon cannot mmap the io_cmd_buf */
2691 ub->mm = NULL;
2692 ub->nr_queues_ready = 0;
2693 ub->nr_privileged_daemon = 0;
2694 init_completion(&ub->completion);
2695 ret = 0;
2696 out_unlock:
2697 mutex_unlock(&ub->mutex);
2698 return ret;
2699 }
2700
ublk_ctrl_end_recovery(struct ublk_device * ub,struct io_uring_cmd * cmd)2701 static int ublk_ctrl_end_recovery(struct ublk_device *ub,
2702 struct io_uring_cmd *cmd)
2703 {
2704 const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
2705 int ublksrv_pid = (int)header->data[0];
2706 int ret = -EINVAL;
2707
2708 pr_devel("%s: Waiting for new ubq_daemons(nr: %d) are ready, dev id %d...\n",
2709 __func__, ub->dev_info.nr_hw_queues, header->dev_id);
2710 /* wait until new ubq_daemon sending all FETCH_REQ */
2711 if (wait_for_completion_interruptible(&ub->completion))
2712 return -EINTR;
2713
2714 pr_devel("%s: All new ubq_daemons(nr: %d) are ready, dev id %d\n",
2715 __func__, ub->dev_info.nr_hw_queues, header->dev_id);
2716
2717 mutex_lock(&ub->mutex);
2718 if (!ublk_can_use_recovery(ub))
2719 goto out_unlock;
2720
2721 if (ub->dev_info.state != UBLK_S_DEV_QUIESCED) {
2722 ret = -EBUSY;
2723 goto out_unlock;
2724 }
2725 ub->dev_info.ublksrv_pid = ublksrv_pid;
2726 pr_devel("%s: new ublksrv_pid %d, dev id %d\n",
2727 __func__, ublksrv_pid, header->dev_id);
2728 blk_mq_unquiesce_queue(ub->ub_disk->queue);
2729 pr_devel("%s: queue unquiesced, dev id %d.\n",
2730 __func__, header->dev_id);
2731 blk_mq_kick_requeue_list(ub->ub_disk->queue);
2732 ub->dev_info.state = UBLK_S_DEV_LIVE;
2733 ret = 0;
2734 out_unlock:
2735 mutex_unlock(&ub->mutex);
2736 return ret;
2737 }
2738
ublk_ctrl_get_features(struct io_uring_cmd * cmd)2739 static int ublk_ctrl_get_features(struct io_uring_cmd *cmd)
2740 {
2741 const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
2742 void __user *argp = (void __user *)(unsigned long)header->addr;
2743 u64 features = UBLK_F_ALL & ~UBLK_F_SUPPORT_ZERO_COPY;
2744
2745 if (header->len != UBLK_FEATURES_LEN || !header->addr)
2746 return -EINVAL;
2747
2748 if (copy_to_user(argp, &features, UBLK_FEATURES_LEN))
2749 return -EFAULT;
2750
2751 return 0;
2752 }
2753
2754 /*
2755 * All control commands are sent via /dev/ublk-control, so we have to check
2756 * the destination device's permission
2757 */
ublk_char_dev_permission(struct ublk_device * ub,const char * dev_path,int mask)2758 static int ublk_char_dev_permission(struct ublk_device *ub,
2759 const char *dev_path, int mask)
2760 {
2761 int err;
2762 struct path path;
2763 struct kstat stat;
2764
2765 err = kern_path(dev_path, LOOKUP_FOLLOW, &path);
2766 if (err)
2767 return err;
2768
2769 err = vfs_getattr(&path, &stat, STATX_TYPE, AT_STATX_SYNC_AS_STAT);
2770 if (err)
2771 goto exit;
2772
2773 err = -EPERM;
2774 if (stat.rdev != ub->cdev_dev.devt || !S_ISCHR(stat.mode))
2775 goto exit;
2776
2777 err = inode_permission(&nop_mnt_idmap,
2778 d_backing_inode(path.dentry), mask);
2779 exit:
2780 path_put(&path);
2781 return err;
2782 }
2783
ublk_ctrl_uring_cmd_permission(struct ublk_device * ub,struct io_uring_cmd * cmd)2784 static int ublk_ctrl_uring_cmd_permission(struct ublk_device *ub,
2785 struct io_uring_cmd *cmd)
2786 {
2787 struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)io_uring_sqe_cmd(cmd->sqe);
2788 bool unprivileged = ub->dev_info.flags & UBLK_F_UNPRIVILEGED_DEV;
2789 void __user *argp = (void __user *)(unsigned long)header->addr;
2790 char *dev_path = NULL;
2791 int ret = 0;
2792 int mask;
2793
2794 if (!unprivileged) {
2795 if (!capable(CAP_SYS_ADMIN))
2796 return -EPERM;
2797 /*
2798 * The new added command of UBLK_CMD_GET_DEV_INFO2 includes
2799 * char_dev_path in payload too, since userspace may not
2800 * know if the specified device is created as unprivileged
2801 * mode.
2802 */
2803 if (_IOC_NR(cmd->cmd_op) != UBLK_CMD_GET_DEV_INFO2)
2804 return 0;
2805 }
2806
2807 /*
2808 * User has to provide the char device path for unprivileged ublk
2809 *
2810 * header->addr always points to the dev path buffer, and
2811 * header->dev_path_len records length of dev path buffer.
2812 */
2813 if (!header->dev_path_len || header->dev_path_len > PATH_MAX)
2814 return -EINVAL;
2815
2816 if (header->len < header->dev_path_len)
2817 return -EINVAL;
2818
2819 dev_path = memdup_user_nul(argp, header->dev_path_len);
2820 if (IS_ERR(dev_path))
2821 return PTR_ERR(dev_path);
2822
2823 ret = -EINVAL;
2824 switch (_IOC_NR(cmd->cmd_op)) {
2825 case UBLK_CMD_GET_DEV_INFO:
2826 case UBLK_CMD_GET_DEV_INFO2:
2827 case UBLK_CMD_GET_QUEUE_AFFINITY:
2828 case UBLK_CMD_GET_PARAMS:
2829 case (_IOC_NR(UBLK_U_CMD_GET_FEATURES)):
2830 mask = MAY_READ;
2831 break;
2832 case UBLK_CMD_START_DEV:
2833 case UBLK_CMD_STOP_DEV:
2834 case UBLK_CMD_ADD_DEV:
2835 case UBLK_CMD_DEL_DEV:
2836 case UBLK_CMD_SET_PARAMS:
2837 case UBLK_CMD_START_USER_RECOVERY:
2838 case UBLK_CMD_END_USER_RECOVERY:
2839 mask = MAY_READ | MAY_WRITE;
2840 break;
2841 default:
2842 goto exit;
2843 }
2844
2845 ret = ublk_char_dev_permission(ub, dev_path, mask);
2846 if (!ret) {
2847 header->len -= header->dev_path_len;
2848 header->addr += header->dev_path_len;
2849 }
2850 pr_devel("%s: dev id %d cmd_op %x uid %d gid %d path %s ret %d\n",
2851 __func__, ub->ub_number, cmd->cmd_op,
2852 ub->dev_info.owner_uid, ub->dev_info.owner_gid,
2853 dev_path, ret);
2854 exit:
2855 kfree(dev_path);
2856 return ret;
2857 }
2858
ublk_ctrl_uring_cmd(struct io_uring_cmd * cmd,unsigned int issue_flags)2859 static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd,
2860 unsigned int issue_flags)
2861 {
2862 const struct ublksrv_ctrl_cmd *header = io_uring_sqe_cmd(cmd->sqe);
2863 struct ublk_device *ub = NULL;
2864 u32 cmd_op = cmd->cmd_op;
2865 int ret = -EINVAL;
2866
2867 if (issue_flags & IO_URING_F_NONBLOCK)
2868 return -EAGAIN;
2869
2870 ublk_ctrl_cmd_dump(cmd);
2871
2872 if (!(issue_flags & IO_URING_F_SQE128))
2873 goto out;
2874
2875 ret = ublk_check_cmd_op(cmd_op);
2876 if (ret)
2877 goto out;
2878
2879 if (cmd_op == UBLK_U_CMD_GET_FEATURES) {
2880 ret = ublk_ctrl_get_features(cmd);
2881 goto out;
2882 }
2883
2884 if (_IOC_NR(cmd_op) != UBLK_CMD_ADD_DEV) {
2885 ret = -ENODEV;
2886 ub = ublk_get_device_from_id(header->dev_id);
2887 if (!ub)
2888 goto out;
2889
2890 ret = ublk_ctrl_uring_cmd_permission(ub, cmd);
2891 if (ret)
2892 goto put_dev;
2893 }
2894
2895 switch (_IOC_NR(cmd_op)) {
2896 case UBLK_CMD_START_DEV:
2897 ret = ublk_ctrl_start_dev(ub, cmd);
2898 break;
2899 case UBLK_CMD_STOP_DEV:
2900 ret = ublk_ctrl_stop_dev(ub);
2901 break;
2902 case UBLK_CMD_GET_DEV_INFO:
2903 case UBLK_CMD_GET_DEV_INFO2:
2904 ret = ublk_ctrl_get_dev_info(ub, cmd);
2905 break;
2906 case UBLK_CMD_ADD_DEV:
2907 ret = ublk_ctrl_add_dev(cmd);
2908 break;
2909 case UBLK_CMD_DEL_DEV:
2910 ret = ublk_ctrl_del_dev(&ub);
2911 break;
2912 case UBLK_CMD_GET_QUEUE_AFFINITY:
2913 ret = ublk_ctrl_get_queue_affinity(ub, cmd);
2914 break;
2915 case UBLK_CMD_GET_PARAMS:
2916 ret = ublk_ctrl_get_params(ub, cmd);
2917 break;
2918 case UBLK_CMD_SET_PARAMS:
2919 ret = ublk_ctrl_set_params(ub, cmd);
2920 break;
2921 case UBLK_CMD_START_USER_RECOVERY:
2922 ret = ublk_ctrl_start_recovery(ub, cmd);
2923 break;
2924 case UBLK_CMD_END_USER_RECOVERY:
2925 ret = ublk_ctrl_end_recovery(ub, cmd);
2926 break;
2927 default:
2928 ret = -ENOTSUPP;
2929 break;
2930 }
2931
2932 put_dev:
2933 if (ub)
2934 ublk_put_device(ub);
2935 out:
2936 io_uring_cmd_done(cmd, ret, 0, issue_flags);
2937 pr_devel("%s: cmd done ret %d cmd_op %x, dev id %d qid %d\n",
2938 __func__, ret, cmd->cmd_op, header->dev_id, header->queue_id);
2939 return -EIOCBQUEUED;
2940 }
2941
2942 static const struct file_operations ublk_ctl_fops = {
2943 .open = nonseekable_open,
2944 .uring_cmd = ublk_ctrl_uring_cmd,
2945 .owner = THIS_MODULE,
2946 .llseek = noop_llseek,
2947 };
2948
2949 static struct miscdevice ublk_misc = {
2950 .minor = MISC_DYNAMIC_MINOR,
2951 .name = "ublk-control",
2952 .fops = &ublk_ctl_fops,
2953 };
2954
ublk_init(void)2955 static int __init ublk_init(void)
2956 {
2957 int ret;
2958
2959 BUILD_BUG_ON((u64)UBLKSRV_IO_BUF_OFFSET +
2960 UBLKSRV_IO_BUF_TOTAL_SIZE < UBLKSRV_IO_BUF_OFFSET);
2961
2962 init_waitqueue_head(&ublk_idr_wq);
2963
2964 ret = misc_register(&ublk_misc);
2965 if (ret)
2966 return ret;
2967
2968 ret = alloc_chrdev_region(&ublk_chr_devt, 0, UBLK_MINORS, "ublk-char");
2969 if (ret)
2970 goto unregister_mis;
2971
2972 ret = class_register(&ublk_chr_class);
2973 if (ret)
2974 goto free_chrdev_region;
2975
2976 return 0;
2977
2978 free_chrdev_region:
2979 unregister_chrdev_region(ublk_chr_devt, UBLK_MINORS);
2980 unregister_mis:
2981 misc_deregister(&ublk_misc);
2982 return ret;
2983 }
2984
ublk_exit(void)2985 static void __exit ublk_exit(void)
2986 {
2987 struct ublk_device *ub;
2988 int id;
2989
2990 idr_for_each_entry(&ublk_index_idr, ub, id)
2991 ublk_remove(ub);
2992
2993 class_unregister(&ublk_chr_class);
2994 misc_deregister(&ublk_misc);
2995
2996 idr_destroy(&ublk_index_idr);
2997 unregister_chrdev_region(ublk_chr_devt, UBLK_MINORS);
2998 }
2999
3000 module_init(ublk_init);
3001 module_exit(ublk_exit);
3002
ublk_set_max_ublks(const char * buf,const struct kernel_param * kp)3003 static int ublk_set_max_ublks(const char *buf, const struct kernel_param *kp)
3004 {
3005 return param_set_uint_minmax(buf, kp, 0, UBLK_MAX_UBLKS);
3006 }
3007
ublk_get_max_ublks(char * buf,const struct kernel_param * kp)3008 static int ublk_get_max_ublks(char *buf, const struct kernel_param *kp)
3009 {
3010 return sysfs_emit(buf, "%u\n", ublks_max);
3011 }
3012
3013 static const struct kernel_param_ops ublk_max_ublks_ops = {
3014 .set = ublk_set_max_ublks,
3015 .get = ublk_get_max_ublks,
3016 };
3017
3018 module_param_cb(ublks_max, &ublk_max_ublks_ops, &ublks_max, 0644);
3019 MODULE_PARM_DESC(ublks_max, "max number of ublk devices allowed to add(default: 64)");
3020
3021 MODULE_AUTHOR("Ming Lei <ming.lei@redhat.com>");
3022 MODULE_LICENSE("GPL");
3023