1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * RDMA Network Block Driver
5 * Copyright (c) 2014 - 2018 ProfitBricks GmbH. All rights reserved.
6 * Copyright (c) 2018 - 2019 1&1 IONOS Cloud GmbH. All rights reserved.
7 * Copyright (c) 2019 - 2020 1&1 IONOS SE. All rights reserved.
11 #define pr_fmt(fmt) KBUILD_MODNAME " L" __stringify(__LINE__) ": " fmt
13 #include <linux/module.h>
14 #include <linux/blkdev.h>
15 #include <linux/hdreg.h>
16 #include <linux/scatterlist.h>
17 #include <linux/idr.h>
21 MODULE_DESCRIPTION("RDMA Network Block Device Client");
22 MODULE_LICENSE("GPL");
24 static int rnbd_client_major;
25 static DEFINE_IDA(index_ida);
26 static DEFINE_MUTEX(ida_lock);
27 static DEFINE_MUTEX(sess_lock);
28 static LIST_HEAD(sess_list);
31 * Maximum number of partitions an instance can have.
32 * 6 bits = 64 minors = 63 partitions (one minor is used for the device itself)
34 #define RNBD_PART_BITS 6
36 static inline bool rnbd_clt_get_sess(struct rnbd_clt_session *sess)
38 return refcount_inc_not_zero(&sess->refcount);
41 static void free_sess(struct rnbd_clt_session *sess);
43 static void rnbd_clt_put_sess(struct rnbd_clt_session *sess)
47 if (refcount_dec_and_test(&sess->refcount))
51 static void rnbd_clt_put_dev(struct rnbd_clt_dev *dev)
55 if (!refcount_dec_and_test(&dev->refcount))
58 mutex_lock(&ida_lock);
59 ida_simple_remove(&index_ida, dev->clt_device_id);
60 mutex_unlock(&ida_lock);
61 kfree(dev->hw_queues);
63 rnbd_clt_put_sess(dev->sess);
64 mutex_destroy(&dev->lock);
68 static inline bool rnbd_clt_get_dev(struct rnbd_clt_dev *dev)
70 return refcount_inc_not_zero(&dev->refcount);
73 static int rnbd_clt_set_dev_attr(struct rnbd_clt_dev *dev,
74 const struct rnbd_msg_open_rsp *rsp)
76 struct rnbd_clt_session *sess = dev->sess;
78 if (!rsp->logical_block_size)
81 dev->device_id = le32_to_cpu(rsp->device_id);
82 dev->nsectors = le64_to_cpu(rsp->nsectors);
83 dev->logical_block_size = le16_to_cpu(rsp->logical_block_size);
84 dev->physical_block_size = le16_to_cpu(rsp->physical_block_size);
85 dev->max_write_same_sectors = le32_to_cpu(rsp->max_write_same_sectors);
86 dev->max_discard_sectors = le32_to_cpu(rsp->max_discard_sectors);
87 dev->discard_granularity = le32_to_cpu(rsp->discard_granularity);
88 dev->discard_alignment = le32_to_cpu(rsp->discard_alignment);
89 dev->secure_discard = le16_to_cpu(rsp->secure_discard);
90 dev->rotational = rsp->rotational;
92 dev->max_hw_sectors = sess->max_io_size / SECTOR_SIZE;
93 dev->max_segments = BMAX_SEGMENTS;
98 static int rnbd_clt_change_capacity(struct rnbd_clt_dev *dev,
101 rnbd_clt_info(dev, "Device size changed from %zu to %zu sectors\n",
102 dev->nsectors, new_nsectors);
103 dev->nsectors = new_nsectors;
104 set_capacity(dev->gd, dev->nsectors);
105 revalidate_disk_size(dev->gd, true);
109 static int process_msg_open_rsp(struct rnbd_clt_dev *dev,
110 struct rnbd_msg_open_rsp *rsp)
114 mutex_lock(&dev->lock);
115 if (dev->dev_state == DEV_STATE_UNMAPPED) {
117 "Ignoring Open-Response message from server for unmapped device\n");
121 if (dev->dev_state == DEV_STATE_MAPPED_DISCONNECTED) {
122 u64 nsectors = le64_to_cpu(rsp->nsectors);
125 * If the device was remapped and the size changed in the
126 * meantime we need to revalidate it
128 if (dev->nsectors != nsectors)
129 rnbd_clt_change_capacity(dev, nsectors);
130 rnbd_clt_info(dev, "Device online, device remapped successfully\n");
132 err = rnbd_clt_set_dev_attr(dev, rsp);
135 dev->dev_state = DEV_STATE_MAPPED;
138 mutex_unlock(&dev->lock);
143 int rnbd_clt_resize_disk(struct rnbd_clt_dev *dev, size_t newsize)
147 mutex_lock(&dev->lock);
148 if (dev->dev_state != DEV_STATE_MAPPED) {
149 pr_err("Failed to set new size of the device, device is not opened\n");
153 ret = rnbd_clt_change_capacity(dev, newsize);
156 mutex_unlock(&dev->lock);
161 static inline void rnbd_clt_dev_requeue(struct rnbd_queue *q)
163 if (WARN_ON(!q->hctx))
166 /* We can come here from interrupt, thus async=true */
167 blk_mq_run_hw_queue(q->hctx, true);
171 RNBD_DELAY_IFBUSY = -1,
175 * rnbd_get_cpu_qlist() - finds a list with HW queues to be rerun
176 * @sess: Session to find a queue for
177 * @cpu: Cpu to start the search from
180 * Each CPU has a list of HW queues, which needs to be rerun. If a list
181 * is not empty - it is marked with a bit. This function finds first
182 * set bit in a bitmap and returns corresponding CPU list.
184 static struct rnbd_cpu_qlist *
185 rnbd_get_cpu_qlist(struct rnbd_clt_session *sess, int cpu)
189 /* Search from cpu to nr_cpu_ids */
190 bit = find_next_bit(sess->cpu_queues_bm, nr_cpu_ids, cpu);
191 if (bit < nr_cpu_ids) {
192 return per_cpu_ptr(sess->cpu_queues, bit);
193 } else if (cpu != 0) {
194 /* Search from 0 to cpu */
195 bit = find_next_bit(sess->cpu_queues_bm, cpu, 0);
197 return per_cpu_ptr(sess->cpu_queues, bit);
203 static inline int nxt_cpu(int cpu)
205 return (cpu + 1) % nr_cpu_ids;
209 * rnbd_rerun_if_needed() - rerun next queue marked as stopped
210 * @sess: Session to rerun a queue on
213 * Each CPU has it's own list of HW queues, which should be rerun.
214 * Function finds such list with HW queues, takes a list lock, picks up
215 * the first HW queue out of the list and requeues it.
218 * True if the queue was requeued, false otherwise.
223 static bool rnbd_rerun_if_needed(struct rnbd_clt_session *sess)
225 struct rnbd_queue *q = NULL;
226 struct rnbd_cpu_qlist *cpu_q;
231 * To keep fairness and not to let other queues starve we always
232 * try to wake up someone else in round-robin manner. That of course
233 * increases latency but queues always have a chance to be executed.
235 cpup = get_cpu_ptr(sess->cpu_rr);
236 for (cpu_q = rnbd_get_cpu_qlist(sess, nxt_cpu(*cpup)); cpu_q;
237 cpu_q = rnbd_get_cpu_qlist(sess, nxt_cpu(cpu_q->cpu))) {
238 if (!spin_trylock_irqsave(&cpu_q->requeue_lock, flags))
240 if (unlikely(!test_bit(cpu_q->cpu, sess->cpu_queues_bm)))
242 q = list_first_entry_or_null(&cpu_q->requeue_list,
243 typeof(*q), requeue_list);
246 list_del_init(&q->requeue_list);
247 clear_bit_unlock(0, &q->in_list);
249 if (list_empty(&cpu_q->requeue_list)) {
250 /* Clear bit if nothing is left */
252 clear_bit(cpu_q->cpu, sess->cpu_queues_bm);
255 spin_unlock_irqrestore(&cpu_q->requeue_lock, flags);
262 * Saves the CPU that is going to be requeued on the per-cpu var. Just
263 * incrementing it doesn't work because rnbd_get_cpu_qlist() will
264 * always return the first CPU with something on the queue list when the
265 * value stored on the var is greater than the last CPU with something
270 put_cpu_var(sess->cpu_rr);
273 rnbd_clt_dev_requeue(q);
279 * rnbd_rerun_all_if_idle() - rerun all queues left in the list if
280 * session is idling (there are no requests
282 * @sess: Session to rerun the queues on
285 * This function tries to rerun all stopped queues if there are no
286 * requests in-flight anymore. This function tries to solve an obvious
287 * problem, when number of tags < than number of queues (hctx), which
288 * are stopped and put to sleep. If last permit, which has been just put,
289 * does not wake up all left queues (hctxs), IO requests hang forever.
291 * That can happen when all number of permits, say N, have been exhausted
292 * from one CPU, and we have many block devices per session, say M.
293 * Each block device has it's own queue (hctx) for each CPU, so eventually
294 * we can put that number of queues (hctxs) to sleep: M x nr_cpu_ids.
295 * If number of permits N < M x nr_cpu_ids finally we will get an IO hang.
297 * To avoid this hang last caller of rnbd_put_permit() (last caller is the
298 * one who observes sess->busy == 0) must wake up all remaining queues.
303 static void rnbd_rerun_all_if_idle(struct rnbd_clt_session *sess)
308 requeued = rnbd_rerun_if_needed(sess);
309 } while (atomic_read(&sess->busy) == 0 && requeued);
312 static struct rtrs_permit *rnbd_get_permit(struct rnbd_clt_session *sess,
313 enum rtrs_clt_con_type con_type,
316 struct rtrs_permit *permit;
318 permit = rtrs_clt_get_permit(sess->rtrs, con_type,
319 wait ? RTRS_PERMIT_WAIT :
322 /* We have a subtle rare case here, when all permits can be
323 * consumed before busy counter increased. This is safe,
324 * because loser will get NULL as a permit, observe 0 busy
325 * counter and immediately restart the queue himself.
327 atomic_inc(&sess->busy);
332 static void rnbd_put_permit(struct rnbd_clt_session *sess,
333 struct rtrs_permit *permit)
335 rtrs_clt_put_permit(sess->rtrs, permit);
336 atomic_dec(&sess->busy);
337 /* Paired with rnbd_clt_dev_add_to_requeue(). Decrement first
338 * and then check queue bits.
340 smp_mb__after_atomic();
341 rnbd_rerun_all_if_idle(sess);
344 static struct rnbd_iu *rnbd_get_iu(struct rnbd_clt_session *sess,
345 enum rtrs_clt_con_type con_type,
349 struct rtrs_permit *permit;
351 permit = rnbd_get_permit(sess, con_type,
352 wait ? RTRS_PERMIT_WAIT :
354 if (unlikely(!permit))
356 iu = rtrs_permit_to_pdu(permit);
359 * 1st reference is dropped after finishing sending a "user" message,
360 * 2nd reference is dropped after confirmation with the response is
362 * 1st and 2nd can happen in any order, so the rnbd_iu should be
363 * released (rtrs_permit returned to ibbtrs) only leased after both
366 atomic_set(&iu->refcount, 2);
367 init_waitqueue_head(&iu->comp.wait);
368 iu->comp.errno = INT_MAX;
373 static void rnbd_put_iu(struct rnbd_clt_session *sess, struct rnbd_iu *iu)
375 if (atomic_dec_and_test(&iu->refcount))
376 rnbd_put_permit(sess, iu->permit);
379 static void rnbd_softirq_done_fn(struct request *rq)
381 struct rnbd_clt_dev *dev = rq->rq_disk->private_data;
382 struct rnbd_clt_session *sess = dev->sess;
385 iu = blk_mq_rq_to_pdu(rq);
386 rnbd_put_permit(sess, iu->permit);
387 blk_mq_end_request(rq, errno_to_blk_status(iu->errno));
390 static void msg_io_conf(void *priv, int errno)
392 struct rnbd_iu *iu = priv;
393 struct rnbd_clt_dev *dev = iu->dev;
394 struct request *rq = iu->rq;
395 int rw = rq_data_dir(rq);
399 blk_mq_complete_request(rq);
402 rnbd_clt_info_rl(dev, "%s I/O failed with err: %d\n",
403 rw == READ ? "read" : "write", errno);
406 static void wake_up_iu_comp(struct rnbd_iu *iu, int errno)
408 iu->comp.errno = errno;
409 wake_up(&iu->comp.wait);
412 static void msg_conf(void *priv, int errno)
414 struct rnbd_iu *iu = priv;
417 schedule_work(&iu->work);
425 static int send_usr_msg(struct rtrs_clt *rtrs, int dir,
426 struct rnbd_iu *iu, struct kvec *vec,
427 size_t len, struct scatterlist *sg, unsigned int sg_len,
428 void (*conf)(struct work_struct *work),
429 int *errno, enum wait_type wait)
432 struct rtrs_clt_req_ops req_ops;
434 INIT_WORK(&iu->work, conf);
435 req_ops = (struct rtrs_clt_req_ops) {
439 err = rtrs_clt_request(dir, &req_ops, rtrs, iu->permit,
440 vec, 1, len, sg, sg_len);
442 wait_event(iu->comp.wait, iu->comp.errno != INT_MAX);
443 *errno = iu->comp.errno;
451 static void msg_close_conf(struct work_struct *work)
453 struct rnbd_iu *iu = container_of(work, struct rnbd_iu, work);
454 struct rnbd_clt_dev *dev = iu->dev;
456 wake_up_iu_comp(iu, iu->errno);
457 rnbd_put_iu(dev->sess, iu);
458 rnbd_clt_put_dev(dev);
461 static int send_msg_close(struct rnbd_clt_dev *dev, u32 device_id, bool wait)
463 struct rnbd_clt_session *sess = dev->sess;
464 struct rnbd_msg_close msg;
468 .iov_len = sizeof(msg)
472 iu = rnbd_get_iu(sess, RTRS_ADMIN_CON, RTRS_PERMIT_WAIT);
479 sg_mark_end(&iu->sglist[0]);
481 msg.hdr.type = cpu_to_le16(RNBD_MSG_CLOSE);
482 msg.device_id = cpu_to_le32(device_id);
484 WARN_ON(!rnbd_clt_get_dev(dev));
485 err = send_usr_msg(sess->rtrs, WRITE, iu, &vec, 0, NULL, 0,
486 msg_close_conf, &errno, wait);
488 rnbd_clt_put_dev(dev);
489 rnbd_put_iu(sess, iu);
494 rnbd_put_iu(sess, iu);
498 static void msg_open_conf(struct work_struct *work)
500 struct rnbd_iu *iu = container_of(work, struct rnbd_iu, work);
501 struct rnbd_msg_open_rsp *rsp = iu->buf;
502 struct rnbd_clt_dev *dev = iu->dev;
503 int errno = iu->errno;
507 "Opening failed, server responded: %d\n",
510 errno = process_msg_open_rsp(dev, rsp);
512 u32 device_id = le32_to_cpu(rsp->device_id);
514 * If server thinks its fine, but we fail to process
515 * then be nice and send a close to server.
517 (void)send_msg_close(dev, device_id, NO_WAIT);
521 wake_up_iu_comp(iu, errno);
522 rnbd_put_iu(dev->sess, iu);
523 rnbd_clt_put_dev(dev);
526 static void msg_sess_info_conf(struct work_struct *work)
528 struct rnbd_iu *iu = container_of(work, struct rnbd_iu, work);
529 struct rnbd_msg_sess_info_rsp *rsp = iu->buf;
530 struct rnbd_clt_session *sess = iu->sess;
533 sess->ver = min_t(u8, rsp->ver, RNBD_PROTO_VER_MAJOR);
536 wake_up_iu_comp(iu, iu->errno);
537 rnbd_put_iu(sess, iu);
538 rnbd_clt_put_sess(sess);
541 static int send_msg_open(struct rnbd_clt_dev *dev, bool wait)
543 struct rnbd_clt_session *sess = dev->sess;
544 struct rnbd_msg_open_rsp *rsp;
545 struct rnbd_msg_open msg;
549 .iov_len = sizeof(msg)
553 rsp = kzalloc(sizeof(*rsp), GFP_KERNEL);
557 iu = rnbd_get_iu(sess, RTRS_ADMIN_CON, RTRS_PERMIT_WAIT);
566 sg_init_one(iu->sglist, rsp, sizeof(*rsp));
568 msg.hdr.type = cpu_to_le16(RNBD_MSG_OPEN);
569 msg.access_mode = dev->access_mode;
570 strlcpy(msg.dev_name, dev->pathname, sizeof(msg.dev_name));
572 WARN_ON(!rnbd_clt_get_dev(dev));
573 err = send_usr_msg(sess->rtrs, READ, iu,
574 &vec, sizeof(*rsp), iu->sglist, 1,
575 msg_open_conf, &errno, wait);
577 rnbd_clt_put_dev(dev);
578 rnbd_put_iu(sess, iu);
584 rnbd_put_iu(sess, iu);
588 static int send_msg_sess_info(struct rnbd_clt_session *sess, bool wait)
590 struct rnbd_msg_sess_info_rsp *rsp;
591 struct rnbd_msg_sess_info msg;
595 .iov_len = sizeof(msg)
599 rsp = kzalloc(sizeof(*rsp), GFP_KERNEL);
603 iu = rnbd_get_iu(sess, RTRS_ADMIN_CON, RTRS_PERMIT_WAIT);
612 sg_init_one(iu->sglist, rsp, sizeof(*rsp));
614 msg.hdr.type = cpu_to_le16(RNBD_MSG_SESS_INFO);
615 msg.ver = RNBD_PROTO_VER_MAJOR;
617 if (!rnbd_clt_get_sess(sess)) {
619 * That can happen only in one case, when RTRS has restablished
620 * the connection and link_ev() is called, but session is almost
621 * dead, last reference on session is put and caller is waiting
622 * for RTRS to close everything.
627 err = send_usr_msg(sess->rtrs, READ, iu,
628 &vec, sizeof(*rsp), iu->sglist, 1,
629 msg_sess_info_conf, &errno, wait);
631 rnbd_clt_put_sess(sess);
633 rnbd_put_iu(sess, iu);
639 rnbd_put_iu(sess, iu);
643 static void set_dev_states_to_disconnected(struct rnbd_clt_session *sess)
645 struct rnbd_clt_dev *dev;
647 mutex_lock(&sess->lock);
648 list_for_each_entry(dev, &sess->devs_list, list) {
649 rnbd_clt_err(dev, "Device disconnected.\n");
651 mutex_lock(&dev->lock);
652 if (dev->dev_state == DEV_STATE_MAPPED)
653 dev->dev_state = DEV_STATE_MAPPED_DISCONNECTED;
654 mutex_unlock(&dev->lock);
656 mutex_unlock(&sess->lock);
659 static void remap_devs(struct rnbd_clt_session *sess)
661 struct rnbd_clt_dev *dev;
662 struct rtrs_attrs attrs;
666 * Careful here: we are called from RTRS link event directly,
667 * thus we can't send any RTRS request and wait for response
668 * or RTRS will not be able to complete request with failure
669 * if something goes wrong (failing of outstanding requests
670 * happens exactly from the context where we are blocking now).
672 * So to avoid deadlocks each usr message sent from here must
676 err = send_msg_sess_info(sess, NO_WAIT);
678 pr_err("send_msg_sess_info(\"%s\"): %d\n", sess->sessname, err);
682 err = rtrs_clt_query(sess->rtrs, &attrs);
684 pr_err("rtrs_clt_query(\"%s\"): %d\n", sess->sessname, err);
687 mutex_lock(&sess->lock);
688 sess->max_io_size = attrs.max_io_size;
690 list_for_each_entry(dev, &sess->devs_list, list) {
693 mutex_lock(&dev->lock);
694 skip = (dev->dev_state == DEV_STATE_INIT);
695 mutex_unlock(&dev->lock);
698 * When device is establishing connection for the first
699 * time - do not remap, it will be closed soon.
703 rnbd_clt_info(dev, "session reconnected, remapping device\n");
704 err = send_msg_open(dev, NO_WAIT);
706 rnbd_clt_err(dev, "send_msg_open(): %d\n", err);
710 mutex_unlock(&sess->lock);
713 static void rnbd_clt_link_ev(void *priv, enum rtrs_clt_link_ev ev)
715 struct rnbd_clt_session *sess = priv;
718 case RTRS_CLT_LINK_EV_DISCONNECTED:
719 set_dev_states_to_disconnected(sess);
721 case RTRS_CLT_LINK_EV_RECONNECTED:
725 pr_err("Unknown session event received (%d), session: %s\n",
730 static void rnbd_init_cpu_qlists(struct rnbd_cpu_qlist __percpu *cpu_queues)
733 struct rnbd_cpu_qlist *cpu_q;
735 for_each_possible_cpu(cpu) {
736 cpu_q = per_cpu_ptr(cpu_queues, cpu);
739 INIT_LIST_HEAD(&cpu_q->requeue_list);
740 spin_lock_init(&cpu_q->requeue_lock);
744 static void destroy_mq_tags(struct rnbd_clt_session *sess)
746 if (sess->tag_set.tags)
747 blk_mq_free_tag_set(&sess->tag_set);
750 static inline void wake_up_rtrs_waiters(struct rnbd_clt_session *sess)
752 sess->rtrs_ready = true;
753 wake_up_all(&sess->rtrs_waitq);
756 static void close_rtrs(struct rnbd_clt_session *sess)
760 if (!IS_ERR_OR_NULL(sess->rtrs)) {
761 rtrs_clt_close(sess->rtrs);
763 wake_up_rtrs_waiters(sess);
767 static void free_sess(struct rnbd_clt_session *sess)
769 WARN_ON(!list_empty(&sess->devs_list));
774 destroy_mq_tags(sess);
775 if (!list_empty(&sess->list)) {
776 mutex_lock(&sess_lock);
777 list_del(&sess->list);
778 mutex_unlock(&sess_lock);
780 free_percpu(sess->cpu_queues);
781 free_percpu(sess->cpu_rr);
782 mutex_destroy(&sess->lock);
786 static struct rnbd_clt_session *alloc_sess(const char *sessname)
788 struct rnbd_clt_session *sess;
791 sess = kzalloc_node(sizeof(*sess), GFP_KERNEL, NUMA_NO_NODE);
793 return ERR_PTR(-ENOMEM);
794 strlcpy(sess->sessname, sessname, sizeof(sess->sessname));
795 atomic_set(&sess->busy, 0);
796 mutex_init(&sess->lock);
797 INIT_LIST_HEAD(&sess->devs_list);
798 INIT_LIST_HEAD(&sess->list);
799 bitmap_zero(sess->cpu_queues_bm, NR_CPUS);
800 init_waitqueue_head(&sess->rtrs_waitq);
801 refcount_set(&sess->refcount, 1);
803 sess->cpu_queues = alloc_percpu(struct rnbd_cpu_qlist);
804 if (!sess->cpu_queues) {
808 rnbd_init_cpu_qlists(sess->cpu_queues);
811 * That is simple percpu variable which stores cpu indeces, which are
812 * incremented on each access. We need that for the sake of fairness
813 * to wake up queues in a round-robin manner.
815 sess->cpu_rr = alloc_percpu(int);
820 for_each_possible_cpu(cpu)
821 * per_cpu_ptr(sess->cpu_rr, cpu) = cpu;
831 static int wait_for_rtrs_connection(struct rnbd_clt_session *sess)
833 wait_event(sess->rtrs_waitq, sess->rtrs_ready);
834 if (IS_ERR_OR_NULL(sess->rtrs))
840 static void wait_for_rtrs_disconnection(struct rnbd_clt_session *sess)
841 __releases(&sess_lock)
842 __acquires(&sess_lock)
846 prepare_to_wait(&sess->rtrs_waitq, &wait, TASK_UNINTERRUPTIBLE);
847 if (IS_ERR_OR_NULL(sess->rtrs)) {
848 finish_wait(&sess->rtrs_waitq, &wait);
851 mutex_unlock(&sess_lock);
852 /* loop in caller, see __find_and_get_sess().
853 * You can't leave mutex locked and call schedule(), you will catch a
854 * deadlock with a caller of free_sess(), which has just put the last
855 * reference and is about to take the sess_lock in order to delete
856 * the session from the list.
859 mutex_lock(&sess_lock);
862 static struct rnbd_clt_session *__find_and_get_sess(const char *sessname)
863 __releases(&sess_lock)
864 __acquires(&sess_lock)
866 struct rnbd_clt_session *sess, *sn;
870 list_for_each_entry_safe(sess, sn, &sess_list, list) {
871 if (strcmp(sessname, sess->sessname))
874 if (sess->rtrs_ready && IS_ERR_OR_NULL(sess->rtrs))
876 * No RTRS connection, session is dying.
880 if (rnbd_clt_get_sess(sess)) {
882 * Alive session is found, wait for RTRS connection.
884 mutex_unlock(&sess_lock);
885 err = wait_for_rtrs_connection(sess);
887 rnbd_clt_put_sess(sess);
888 mutex_lock(&sess_lock);
891 /* Session is dying, repeat the loop */
897 * Ref is 0, session is dying, wait for RTRS disconnect
898 * in order to avoid session names clashes.
900 wait_for_rtrs_disconnection(sess);
902 * RTRS is disconnected and soon session will be freed,
912 rnbd_clt_session *find_or_create_sess(const char *sessname, bool *first)
914 struct rnbd_clt_session *sess = NULL;
916 mutex_lock(&sess_lock);
917 sess = __find_and_get_sess(sessname);
919 sess = alloc_sess(sessname);
921 mutex_unlock(&sess_lock);
924 list_add(&sess->list, &sess_list);
928 mutex_unlock(&sess_lock);
933 static int rnbd_client_open(struct block_device *block_device, fmode_t mode)
935 struct rnbd_clt_dev *dev = block_device->bd_disk->private_data;
937 if (dev->read_only && (mode & FMODE_WRITE))
940 if (dev->dev_state == DEV_STATE_UNMAPPED ||
941 !rnbd_clt_get_dev(dev))
947 static void rnbd_client_release(struct gendisk *gen, fmode_t mode)
949 struct rnbd_clt_dev *dev = gen->private_data;
951 rnbd_clt_put_dev(dev);
954 static int rnbd_client_getgeo(struct block_device *block_device,
955 struct hd_geometry *geo)
958 struct rnbd_clt_dev *dev;
960 dev = block_device->bd_disk->private_data;
961 size = dev->size * (dev->logical_block_size / SECTOR_SIZE);
962 geo->cylinders = size >> 6; /* size/64 */
970 static const struct block_device_operations rnbd_client_ops = {
971 .owner = THIS_MODULE,
972 .open = rnbd_client_open,
973 .release = rnbd_client_release,
974 .getgeo = rnbd_client_getgeo
977 /* The amount of data that belongs to an I/O and the amount of data that
978 * should be read or written to the disk (bi_size) can differ.
980 * E.g. When WRITE_SAME is used, only a small amount of data is
981 * transferred that is then written repeatedly over a lot of sectors.
983 * Get the size of data to be transferred via RTRS by summing up the size
984 * of the scather-gather list entries.
986 static size_t rnbd_clt_get_sg_size(struct scatterlist *sglist, u32 len)
988 struct scatterlist *sg;
992 for_each_sg(sglist, sg, len, i)
997 static int rnbd_client_xfer_request(struct rnbd_clt_dev *dev,
1001 struct rtrs_clt *rtrs = dev->sess->rtrs;
1002 struct rtrs_permit *permit = iu->permit;
1003 struct rnbd_msg_io msg;
1004 struct rtrs_clt_req_ops req_ops;
1005 unsigned int sg_cnt = 0;
1012 msg.sector = cpu_to_le64(blk_rq_pos(rq));
1013 msg.bi_size = cpu_to_le32(blk_rq_bytes(rq));
1014 msg.rw = cpu_to_le32(rq_to_rnbd_flags(rq));
1015 msg.prio = cpu_to_le16(req_get_ioprio(rq));
1018 * We only support discards with single segment for now.
1021 if (req_op(rq) != REQ_OP_DISCARD)
1022 sg_cnt = blk_rq_map_sg(dev->queue, rq, iu->sglist);
1025 /* Do not forget to mark the end */
1026 sg_mark_end(&iu->sglist[0]);
1028 msg.hdr.type = cpu_to_le16(RNBD_MSG_IO);
1029 msg.device_id = cpu_to_le32(dev->device_id);
1031 vec = (struct kvec) {
1033 .iov_len = sizeof(msg)
1035 size = rnbd_clt_get_sg_size(iu->sglist, sg_cnt);
1036 req_ops = (struct rtrs_clt_req_ops) {
1038 .conf_fn = msg_io_conf,
1040 err = rtrs_clt_request(rq_data_dir(rq), &req_ops, rtrs, permit,
1041 &vec, 1, size, iu->sglist, sg_cnt);
1042 if (unlikely(err)) {
1043 rnbd_clt_err_rl(dev, "RTRS failed to transfer IO, err: %d\n",
1052 * rnbd_clt_dev_add_to_requeue() - add device to requeue if session is busy
1053 * @dev: Device to be checked
1054 * @q: Queue to be added to the requeue list if required
1057 * If session is busy, that means someone will requeue us when resources
1058 * are freed. If session is not doing anything - device is not added to
1059 * the list and @false is returned.
1061 static bool rnbd_clt_dev_add_to_requeue(struct rnbd_clt_dev *dev,
1062 struct rnbd_queue *q)
1064 struct rnbd_clt_session *sess = dev->sess;
1065 struct rnbd_cpu_qlist *cpu_q;
1066 unsigned long flags;
1070 cpu_q = get_cpu_ptr(sess->cpu_queues);
1071 spin_lock_irqsave(&cpu_q->requeue_lock, flags);
1073 if (likely(!test_and_set_bit_lock(0, &q->in_list))) {
1074 if (WARN_ON(!list_empty(&q->requeue_list)))
1077 need_set = !test_bit(cpu_q->cpu, sess->cpu_queues_bm);
1079 set_bit(cpu_q->cpu, sess->cpu_queues_bm);
1080 /* Paired with rnbd_put_permit(). Set a bit first
1081 * and then observe the busy counter.
1083 smp_mb__before_atomic();
1085 if (likely(atomic_read(&sess->busy))) {
1086 list_add_tail(&q->requeue_list, &cpu_q->requeue_list);
1088 /* Very unlikely, but possible: busy counter was
1089 * observed as zero. Drop all bits and return
1090 * false to restart the queue by ourselves.
1093 clear_bit(cpu_q->cpu, sess->cpu_queues_bm);
1094 clear_bit_unlock(0, &q->in_list);
1099 spin_unlock_irqrestore(&cpu_q->requeue_lock, flags);
1100 put_cpu_ptr(sess->cpu_queues);
1105 static void rnbd_clt_dev_kick_mq_queue(struct rnbd_clt_dev *dev,
1106 struct blk_mq_hw_ctx *hctx,
1109 struct rnbd_queue *q = hctx->driver_data;
1111 if (delay != RNBD_DELAY_IFBUSY)
1112 blk_mq_delay_run_hw_queue(hctx, delay);
1113 else if (unlikely(!rnbd_clt_dev_add_to_requeue(dev, q)))
1115 * If session is not busy we have to restart
1116 * the queue ourselves.
1118 blk_mq_delay_run_hw_queue(hctx, 10/*ms*/);
1121 static blk_status_t rnbd_queue_rq(struct blk_mq_hw_ctx *hctx,
1122 const struct blk_mq_queue_data *bd)
1124 struct request *rq = bd->rq;
1125 struct rnbd_clt_dev *dev = rq->rq_disk->private_data;
1126 struct rnbd_iu *iu = blk_mq_rq_to_pdu(rq);
1129 if (unlikely(dev->dev_state != DEV_STATE_MAPPED))
1130 return BLK_STS_IOERR;
1132 iu->permit = rnbd_get_permit(dev->sess, RTRS_IO_CON,
1133 RTRS_PERMIT_NOWAIT);
1134 if (unlikely(!iu->permit)) {
1135 rnbd_clt_dev_kick_mq_queue(dev, hctx, RNBD_DELAY_IFBUSY);
1136 return BLK_STS_RESOURCE;
1139 blk_mq_start_request(rq);
1140 err = rnbd_client_xfer_request(dev, rq, iu);
1141 if (likely(err == 0))
1143 if (unlikely(err == -EAGAIN || err == -ENOMEM)) {
1144 rnbd_clt_dev_kick_mq_queue(dev, hctx, 10/*ms*/);
1145 rnbd_put_permit(dev->sess, iu->permit);
1146 return BLK_STS_RESOURCE;
1149 rnbd_put_permit(dev->sess, iu->permit);
1150 return BLK_STS_IOERR;
1153 static int rnbd_init_request(struct blk_mq_tag_set *set, struct request *rq,
1154 unsigned int hctx_idx, unsigned int numa_node)
1156 struct rnbd_iu *iu = blk_mq_rq_to_pdu(rq);
1158 sg_init_table(iu->sglist, BMAX_SEGMENTS);
1162 static struct blk_mq_ops rnbd_mq_ops = {
1163 .queue_rq = rnbd_queue_rq,
1164 .init_request = rnbd_init_request,
1165 .complete = rnbd_softirq_done_fn,
1168 static int setup_mq_tags(struct rnbd_clt_session *sess)
1170 struct blk_mq_tag_set *tag_set = &sess->tag_set;
1172 memset(tag_set, 0, sizeof(*tag_set));
1173 tag_set->ops = &rnbd_mq_ops;
1174 tag_set->queue_depth = sess->queue_depth;
1175 tag_set->numa_node = NUMA_NO_NODE;
1176 tag_set->flags = BLK_MQ_F_SHOULD_MERGE |
1177 BLK_MQ_F_TAG_QUEUE_SHARED;
1178 tag_set->cmd_size = sizeof(struct rnbd_iu);
1179 tag_set->nr_hw_queues = num_online_cpus();
1181 return blk_mq_alloc_tag_set(tag_set);
1184 static struct rnbd_clt_session *
1185 find_and_get_or_create_sess(const char *sessname,
1186 const struct rtrs_addr *paths,
1187 size_t path_cnt, u16 port_nr)
1189 struct rnbd_clt_session *sess;
1190 struct rtrs_attrs attrs;
1193 struct rtrs_clt_ops rtrs_ops;
1195 sess = find_or_create_sess(sessname, &first);
1196 if (sess == ERR_PTR(-ENOMEM))
1197 return ERR_PTR(-ENOMEM);
1201 rtrs_ops = (struct rtrs_clt_ops) {
1203 .link_ev = rnbd_clt_link_ev,
1206 * Nothing was found, establish rtrs connection and proceed further.
1208 sess->rtrs = rtrs_clt_open(&rtrs_ops, sessname,
1209 paths, path_cnt, port_nr,
1210 sizeof(struct rnbd_iu),
1211 RECONNECT_DELAY, BMAX_SEGMENTS,
1212 BLK_MAX_SEGMENT_SIZE,
1214 if (IS_ERR(sess->rtrs)) {
1215 err = PTR_ERR(sess->rtrs);
1216 goto wake_up_and_put;
1219 err = rtrs_clt_query(sess->rtrs, &attrs);
1223 sess->max_io_size = attrs.max_io_size;
1224 sess->queue_depth = attrs.queue_depth;
1226 err = setup_mq_tags(sess);
1230 err = send_msg_sess_info(sess, WAIT);
1234 wake_up_rtrs_waiters(sess);
1241 rnbd_clt_put_sess(sess);
1243 return ERR_PTR(err);
1246 wake_up_rtrs_waiters(sess);
1250 static inline void rnbd_init_hw_queue(struct rnbd_clt_dev *dev,
1251 struct rnbd_queue *q,
1252 struct blk_mq_hw_ctx *hctx)
1254 INIT_LIST_HEAD(&q->requeue_list);
1259 static void rnbd_init_mq_hw_queues(struct rnbd_clt_dev *dev)
1262 struct blk_mq_hw_ctx *hctx;
1263 struct rnbd_queue *q;
1265 queue_for_each_hw_ctx(dev->queue, hctx, i) {
1266 q = &dev->hw_queues[i];
1267 rnbd_init_hw_queue(dev, q, hctx);
1268 hctx->driver_data = q;
1272 static int setup_mq_dev(struct rnbd_clt_dev *dev)
1274 dev->queue = blk_mq_init_queue(&dev->sess->tag_set);
1275 if (IS_ERR(dev->queue)) {
1276 rnbd_clt_err(dev, "Initializing multiqueue queue failed, err: %ld\n",
1277 PTR_ERR(dev->queue));
1278 return PTR_ERR(dev->queue);
1280 rnbd_init_mq_hw_queues(dev);
1284 static void setup_request_queue(struct rnbd_clt_dev *dev)
1286 blk_queue_logical_block_size(dev->queue, dev->logical_block_size);
1287 blk_queue_physical_block_size(dev->queue, dev->physical_block_size);
1288 blk_queue_max_hw_sectors(dev->queue, dev->max_hw_sectors);
1289 blk_queue_max_write_same_sectors(dev->queue,
1290 dev->max_write_same_sectors);
1293 * we don't support discards to "discontiguous" segments
1296 blk_queue_max_discard_segments(dev->queue, 1);
1298 blk_queue_max_discard_sectors(dev->queue, dev->max_discard_sectors);
1299 dev->queue->limits.discard_granularity = dev->discard_granularity;
1300 dev->queue->limits.discard_alignment = dev->discard_alignment;
1301 if (dev->max_discard_sectors)
1302 blk_queue_flag_set(QUEUE_FLAG_DISCARD, dev->queue);
1303 if (dev->secure_discard)
1304 blk_queue_flag_set(QUEUE_FLAG_SECERASE, dev->queue);
1306 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, dev->queue);
1307 blk_queue_flag_set(QUEUE_FLAG_SAME_FORCE, dev->queue);
1308 blk_queue_max_segments(dev->queue, dev->max_segments);
1309 blk_queue_io_opt(dev->queue, dev->sess->max_io_size);
1310 blk_queue_virt_boundary(dev->queue, SZ_4K - 1);
1311 blk_queue_write_cache(dev->queue, true, true);
1312 dev->queue->queuedata = dev;
1315 static void rnbd_clt_setup_gen_disk(struct rnbd_clt_dev *dev, int idx)
1317 dev->gd->major = rnbd_client_major;
1318 dev->gd->first_minor = idx << RNBD_PART_BITS;
1319 dev->gd->fops = &rnbd_client_ops;
1320 dev->gd->queue = dev->queue;
1321 dev->gd->private_data = dev;
1322 snprintf(dev->gd->disk_name, sizeof(dev->gd->disk_name), "rnbd%d",
1324 pr_debug("disk_name=%s, capacity=%zu\n",
1326 dev->nsectors * (dev->logical_block_size / SECTOR_SIZE)
1329 set_capacity(dev->gd, dev->nsectors);
1331 if (dev->access_mode == RNBD_ACCESS_RO) {
1332 dev->read_only = true;
1333 set_disk_ro(dev->gd, true);
1335 dev->read_only = false;
1338 if (!dev->rotational)
1339 blk_queue_flag_set(QUEUE_FLAG_NONROT, dev->queue);
1342 static int rnbd_client_setup_device(struct rnbd_clt_session *sess,
1343 struct rnbd_clt_dev *dev, int idx)
1347 dev->size = dev->nsectors * dev->logical_block_size;
1349 err = setup_mq_dev(dev);
1353 setup_request_queue(dev);
1355 dev->gd = alloc_disk_node(1 << RNBD_PART_BITS, NUMA_NO_NODE);
1357 blk_cleanup_queue(dev->queue);
1361 rnbd_clt_setup_gen_disk(dev, idx);
1366 static struct rnbd_clt_dev *init_dev(struct rnbd_clt_session *sess,
1367 enum rnbd_access_mode access_mode,
1368 const char *pathname)
1370 struct rnbd_clt_dev *dev;
1373 dev = kzalloc_node(sizeof(*dev), GFP_KERNEL, NUMA_NO_NODE);
1375 return ERR_PTR(-ENOMEM);
1377 dev->hw_queues = kcalloc(nr_cpu_ids, sizeof(*dev->hw_queues),
1379 if (!dev->hw_queues) {
1384 mutex_lock(&ida_lock);
1385 ret = ida_simple_get(&index_ida, 0, 1 << (MINORBITS - RNBD_PART_BITS),
1387 mutex_unlock(&ida_lock);
1389 pr_err("Failed to initialize device '%s' from session %s, allocating idr failed, err: %d\n",
1390 pathname, sess->sessname, ret);
1394 dev->pathname = kstrdup(pathname, GFP_KERNEL);
1395 if (!dev->pathname) {
1400 dev->clt_device_id = ret;
1402 dev->access_mode = access_mode;
1403 mutex_init(&dev->lock);
1404 refcount_set(&dev->refcount, 1);
1405 dev->dev_state = DEV_STATE_INIT;
1408 * Here we called from sysfs entry, thus clt-sysfs is
1409 * responsible that session will not disappear.
1411 WARN_ON(!rnbd_clt_get_sess(sess));
1416 kfree(dev->hw_queues);
1419 return ERR_PTR(ret);
1422 static bool __exists_dev(const char *pathname)
1424 struct rnbd_clt_session *sess;
1425 struct rnbd_clt_dev *dev;
1428 list_for_each_entry(sess, &sess_list, list) {
1429 mutex_lock(&sess->lock);
1430 list_for_each_entry(dev, &sess->devs_list, list) {
1431 if (strlen(dev->pathname) == strlen(pathname) &&
1432 !strcmp(dev->pathname, pathname)) {
1437 mutex_unlock(&sess->lock);
1445 static bool exists_devpath(const char *pathname)
1449 mutex_lock(&sess_lock);
1450 found = __exists_dev(pathname);
1451 mutex_unlock(&sess_lock);
1456 static bool insert_dev_if_not_exists_devpath(const char *pathname,
1457 struct rnbd_clt_session *sess,
1458 struct rnbd_clt_dev *dev)
1462 mutex_lock(&sess_lock);
1463 found = __exists_dev(pathname);
1465 mutex_lock(&sess->lock);
1466 list_add_tail(&dev->list, &sess->devs_list);
1467 mutex_unlock(&sess->lock);
1469 mutex_unlock(&sess_lock);
1474 static void delete_dev(struct rnbd_clt_dev *dev)
1476 struct rnbd_clt_session *sess = dev->sess;
1478 mutex_lock(&sess->lock);
1479 list_del(&dev->list);
1480 mutex_unlock(&sess->lock);
1483 struct rnbd_clt_dev *rnbd_clt_map_device(const char *sessname,
1484 struct rtrs_addr *paths,
1485 size_t path_cnt, u16 port_nr,
1486 const char *pathname,
1487 enum rnbd_access_mode access_mode)
1489 struct rnbd_clt_session *sess;
1490 struct rnbd_clt_dev *dev;
1493 if (exists_devpath(pathname))
1494 return ERR_PTR(-EEXIST);
1496 sess = find_and_get_or_create_sess(sessname, paths, path_cnt, port_nr);
1498 return ERR_CAST(sess);
1500 dev = init_dev(sess, access_mode, pathname);
1502 pr_err("map_device: failed to map device '%s' from session %s, can't initialize device, err: %ld\n",
1503 pathname, sess->sessname, PTR_ERR(dev));
1507 if (insert_dev_if_not_exists_devpath(pathname, sess, dev)) {
1511 ret = send_msg_open(dev, WAIT);
1514 "map_device: failed, can't open remote device, err: %d\n",
1518 mutex_lock(&dev->lock);
1519 pr_debug("Opened remote device: session=%s, path='%s'\n",
1520 sess->sessname, pathname);
1521 ret = rnbd_client_setup_device(sess, dev, dev->clt_device_id);
1524 "map_device: Failed to configure device, err: %d\n",
1526 mutex_unlock(&dev->lock);
1531 "map_device: Device mapped as %s (nsectors: %zu, logical_block_size: %d, physical_block_size: %d, max_write_same_sectors: %d, max_discard_sectors: %d, discard_granularity: %d, discard_alignment: %d, secure_discard: %d, max_segments: %d, max_hw_sectors: %d, rotational: %d)\n",
1532 dev->gd->disk_name, dev->nsectors,
1533 dev->logical_block_size, dev->physical_block_size,
1534 dev->max_write_same_sectors, dev->max_discard_sectors,
1535 dev->discard_granularity, dev->discard_alignment,
1536 dev->secure_discard, dev->max_segments,
1537 dev->max_hw_sectors, dev->rotational);
1539 mutex_unlock(&dev->lock);
1542 rnbd_clt_put_sess(sess);
1547 send_msg_close(dev, dev->device_id, WAIT);
1551 rnbd_clt_put_dev(dev);
1553 rnbd_clt_put_sess(sess);
1555 return ERR_PTR(ret);
1558 static void destroy_gen_disk(struct rnbd_clt_dev *dev)
1560 del_gendisk(dev->gd);
1561 blk_cleanup_queue(dev->queue);
1565 static void destroy_sysfs(struct rnbd_clt_dev *dev,
1566 const struct attribute *sysfs_self)
1568 rnbd_clt_remove_dev_symlink(dev);
1569 if (dev->kobj.state_initialized) {
1571 /* To avoid deadlock firstly remove itself */
1572 sysfs_remove_file_self(&dev->kobj, sysfs_self);
1573 kobject_del(&dev->kobj);
1574 kobject_put(&dev->kobj);
1578 int rnbd_clt_unmap_device(struct rnbd_clt_dev *dev, bool force,
1579 const struct attribute *sysfs_self)
1581 struct rnbd_clt_session *sess = dev->sess;
1582 int refcount, ret = 0;
1585 mutex_lock(&dev->lock);
1586 if (dev->dev_state == DEV_STATE_UNMAPPED) {
1587 rnbd_clt_info(dev, "Device is already being unmapped\n");
1591 refcount = refcount_read(&dev->refcount);
1592 if (!force && refcount > 1) {
1594 "Closing device failed, device is in use, (%d device users)\n",
1599 was_mapped = (dev->dev_state == DEV_STATE_MAPPED);
1600 dev->dev_state = DEV_STATE_UNMAPPED;
1601 mutex_unlock(&dev->lock);
1604 destroy_sysfs(dev, sysfs_self);
1605 destroy_gen_disk(dev);
1606 if (was_mapped && sess->rtrs)
1607 send_msg_close(dev, dev->device_id, WAIT);
1609 rnbd_clt_info(dev, "Device is unmapped\n");
1611 /* Likely last reference put */
1612 rnbd_clt_put_dev(dev);
1615 * Here device and session can be vanished!
1620 mutex_unlock(&dev->lock);
1625 int rnbd_clt_remap_device(struct rnbd_clt_dev *dev)
1629 mutex_lock(&dev->lock);
1630 if (dev->dev_state == DEV_STATE_MAPPED_DISCONNECTED)
1632 else if (dev->dev_state == DEV_STATE_UNMAPPED)
1634 else if (dev->dev_state == DEV_STATE_MAPPED)
1638 mutex_unlock(&dev->lock);
1640 rnbd_clt_info(dev, "Remapping device.\n");
1641 err = send_msg_open(dev, WAIT);
1643 rnbd_clt_err(dev, "remap_device: %d\n", err);
1649 static void unmap_device_work(struct work_struct *work)
1651 struct rnbd_clt_dev *dev;
1653 dev = container_of(work, typeof(*dev), unmap_on_rmmod_work);
1654 rnbd_clt_unmap_device(dev, true, NULL);
1657 static void rnbd_destroy_sessions(void)
1659 struct rnbd_clt_session *sess, *sn;
1660 struct rnbd_clt_dev *dev, *tn;
1662 /* Firstly forbid access through sysfs interface */
1663 rnbd_clt_destroy_default_group();
1664 rnbd_clt_destroy_sysfs_files();
1667 * Here at this point there is no any concurrent access to sessions
1668 * list and devices list:
1669 * 1. New session or device can'be be created - session sysfs files
1671 * 2. Device or session can't be removed - module reference is taken
1672 * into account in unmap device sysfs callback.
1673 * 3. No IO requests inflight - each file open of block_dev increases
1674 * module reference in get_disk().
1676 * But still there can be user requests inflights, which are sent by
1677 * asynchronous send_msg_*() functions, thus before unmapping devices
1678 * RTRS session must be explicitly closed.
1681 list_for_each_entry_safe(sess, sn, &sess_list, list) {
1682 if (!rnbd_clt_get_sess(sess))
1685 list_for_each_entry_safe(dev, tn, &sess->devs_list, list) {
1687 * Here unmap happens in parallel for only one reason:
1688 * blk_cleanup_queue() takes around half a second, so
1689 * on huge amount of devices the whole module unload
1690 * procedure takes minutes.
1692 INIT_WORK(&dev->unmap_on_rmmod_work, unmap_device_work);
1693 queue_work(system_long_wq, &dev->unmap_on_rmmod_work);
1695 rnbd_clt_put_sess(sess);
1697 /* Wait for all scheduled unmap works */
1698 flush_workqueue(system_long_wq);
1699 WARN_ON(!list_empty(&sess_list));
1702 static int __init rnbd_client_init(void)
1706 BUILD_BUG_ON(sizeof(struct rnbd_msg_hdr) != 4);
1707 BUILD_BUG_ON(sizeof(struct rnbd_msg_sess_info) != 36);
1708 BUILD_BUG_ON(sizeof(struct rnbd_msg_sess_info_rsp) != 36);
1709 BUILD_BUG_ON(sizeof(struct rnbd_msg_open) != 264);
1710 BUILD_BUG_ON(sizeof(struct rnbd_msg_close) != 8);
1711 BUILD_BUG_ON(sizeof(struct rnbd_msg_open_rsp) != 56);
1712 rnbd_client_major = register_blkdev(rnbd_client_major, "rnbd");
1713 if (rnbd_client_major <= 0) {
1714 pr_err("Failed to load module, block device registration failed\n");
1718 err = rnbd_clt_create_sysfs_files();
1720 pr_err("Failed to load module, creating sysfs device files failed, err: %d\n",
1722 unregister_blkdev(rnbd_client_major, "rnbd");
1728 static void __exit rnbd_client_exit(void)
1730 rnbd_destroy_sessions();
1731 unregister_blkdev(rnbd_client_major, "rnbd");
1732 ida_destroy(&index_ida);
1735 module_init(rnbd_client_init);
1736 module_exit(rnbd_client_exit);