xref: /linux/tools/testing/selftests/ublk/kublk.c (revision fb7399cf2d0b33825b8039f95c45395c7deba25c)
1 /* SPDX-License-Identifier: MIT */
2 /*
3  * Description: uring_cmd based ublk
4  */
5 
6 #include "kublk.h"
7 
8 #define MAX_NR_TGT_ARG 	64
9 
10 unsigned int ublk_dbg_mask = UBLK_LOG;
11 static const struct ublk_tgt_ops *tgt_ops_list[] = {
12 	&null_tgt_ops,
13 	&loop_tgt_ops,
14 	&stripe_tgt_ops,
15 	&fault_inject_tgt_ops,
16 };
17 
18 static const struct ublk_tgt_ops *ublk_find_tgt(const char *name)
19 {
20 	int i;
21 
22 	if (name == NULL)
23 		return NULL;
24 
25 	for (i = 0; i < ARRAY_SIZE(tgt_ops_list); i++)
26 		if (strcmp(tgt_ops_list[i]->name, name) == 0)
27 			return tgt_ops_list[i];
28 	return NULL;
29 }
30 
31 static inline int ublk_setup_ring(struct io_uring *r, int depth,
32 		int cq_depth, unsigned flags)
33 {
34 	struct io_uring_params p;
35 
36 	memset(&p, 0, sizeof(p));
37 	p.flags = flags | IORING_SETUP_CQSIZE;
38 	p.cq_entries = cq_depth;
39 
40 	return io_uring_queue_init_params(depth, r, &p);
41 }
42 
43 static void ublk_ctrl_init_cmd(struct ublk_dev *dev,
44 		struct io_uring_sqe *sqe,
45 		struct ublk_ctrl_cmd_data *data)
46 {
47 	struct ublksrv_ctrl_dev_info *info = &dev->dev_info;
48 	struct ublksrv_ctrl_cmd *cmd = (struct ublksrv_ctrl_cmd *)ublk_get_sqe_cmd(sqe);
49 
50 	sqe->fd = dev->ctrl_fd;
51 	sqe->opcode = IORING_OP_URING_CMD;
52 	sqe->ioprio = 0;
53 
54 	if (data->flags & CTRL_CMD_HAS_BUF) {
55 		cmd->addr = data->addr;
56 		cmd->len = data->len;
57 	}
58 
59 	if (data->flags & CTRL_CMD_HAS_DATA)
60 		cmd->data[0] = data->data[0];
61 
62 	cmd->dev_id = info->dev_id;
63 	cmd->queue_id = -1;
64 
65 	ublk_set_sqe_cmd_op(sqe, data->cmd_op);
66 
67 	io_uring_sqe_set_data(sqe, cmd);
68 }
69 
70 static int __ublk_ctrl_cmd(struct ublk_dev *dev,
71 		struct ublk_ctrl_cmd_data *data)
72 {
73 	struct io_uring_sqe *sqe;
74 	struct io_uring_cqe *cqe;
75 	int ret = -EINVAL;
76 
77 	sqe = io_uring_get_sqe(&dev->ring);
78 	if (!sqe) {
79 		ublk_err("%s: can't get sqe ret %d\n", __func__, ret);
80 		return ret;
81 	}
82 
83 	ublk_ctrl_init_cmd(dev, sqe, data);
84 
85 	ret = io_uring_submit(&dev->ring);
86 	if (ret < 0) {
87 		ublk_err("uring submit ret %d\n", ret);
88 		return ret;
89 	}
90 
91 	ret = io_uring_wait_cqe(&dev->ring, &cqe);
92 	if (ret < 0) {
93 		ublk_err("wait cqe: %s\n", strerror(-ret));
94 		return ret;
95 	}
96 	io_uring_cqe_seen(&dev->ring, cqe);
97 
98 	return cqe->res;
99 }
100 
101 static int ublk_ctrl_stop_dev(struct ublk_dev *dev)
102 {
103 	struct ublk_ctrl_cmd_data data = {
104 		.cmd_op	= UBLK_U_CMD_STOP_DEV,
105 	};
106 
107 	return __ublk_ctrl_cmd(dev, &data);
108 }
109 
110 static int ublk_ctrl_start_dev(struct ublk_dev *dev,
111 		int daemon_pid)
112 {
113 	struct ublk_ctrl_cmd_data data = {
114 		.cmd_op	= UBLK_U_CMD_START_DEV,
115 		.flags	= CTRL_CMD_HAS_DATA,
116 	};
117 
118 	dev->dev_info.ublksrv_pid = data.data[0] = daemon_pid;
119 
120 	return __ublk_ctrl_cmd(dev, &data);
121 }
122 
123 static int ublk_ctrl_start_user_recovery(struct ublk_dev *dev)
124 {
125 	struct ublk_ctrl_cmd_data data = {
126 		.cmd_op	= UBLK_U_CMD_START_USER_RECOVERY,
127 	};
128 
129 	return __ublk_ctrl_cmd(dev, &data);
130 }
131 
132 static int ublk_ctrl_end_user_recovery(struct ublk_dev *dev, int daemon_pid)
133 {
134 	struct ublk_ctrl_cmd_data data = {
135 		.cmd_op	= UBLK_U_CMD_END_USER_RECOVERY,
136 		.flags	= CTRL_CMD_HAS_DATA,
137 	};
138 
139 	dev->dev_info.ublksrv_pid = data.data[0] = daemon_pid;
140 
141 	return __ublk_ctrl_cmd(dev, &data);
142 }
143 
144 static int ublk_ctrl_add_dev(struct ublk_dev *dev)
145 {
146 	struct ublk_ctrl_cmd_data data = {
147 		.cmd_op	= UBLK_U_CMD_ADD_DEV,
148 		.flags	= CTRL_CMD_HAS_BUF,
149 		.addr = (__u64) (uintptr_t) &dev->dev_info,
150 		.len = sizeof(struct ublksrv_ctrl_dev_info),
151 	};
152 
153 	return __ublk_ctrl_cmd(dev, &data);
154 }
155 
156 static int ublk_ctrl_del_dev(struct ublk_dev *dev)
157 {
158 	struct ublk_ctrl_cmd_data data = {
159 		.cmd_op = UBLK_U_CMD_DEL_DEV,
160 		.flags = 0,
161 	};
162 
163 	return __ublk_ctrl_cmd(dev, &data);
164 }
165 
166 static int ublk_ctrl_get_info(struct ublk_dev *dev)
167 {
168 	struct ublk_ctrl_cmd_data data = {
169 		.cmd_op	= UBLK_U_CMD_GET_DEV_INFO,
170 		.flags	= CTRL_CMD_HAS_BUF,
171 		.addr = (__u64) (uintptr_t) &dev->dev_info,
172 		.len = sizeof(struct ublksrv_ctrl_dev_info),
173 	};
174 
175 	return __ublk_ctrl_cmd(dev, &data);
176 }
177 
178 static int ublk_ctrl_set_params(struct ublk_dev *dev,
179 		struct ublk_params *params)
180 {
181 	struct ublk_ctrl_cmd_data data = {
182 		.cmd_op	= UBLK_U_CMD_SET_PARAMS,
183 		.flags	= CTRL_CMD_HAS_BUF,
184 		.addr = (__u64) (uintptr_t) params,
185 		.len = sizeof(*params),
186 	};
187 	params->len = sizeof(*params);
188 	return __ublk_ctrl_cmd(dev, &data);
189 }
190 
191 static int ublk_ctrl_get_params(struct ublk_dev *dev,
192 		struct ublk_params *params)
193 {
194 	struct ublk_ctrl_cmd_data data = {
195 		.cmd_op	= UBLK_U_CMD_GET_PARAMS,
196 		.flags	= CTRL_CMD_HAS_BUF,
197 		.addr = (__u64)params,
198 		.len = sizeof(*params),
199 	};
200 
201 	params->len = sizeof(*params);
202 
203 	return __ublk_ctrl_cmd(dev, &data);
204 }
205 
206 static int ublk_ctrl_get_features(struct ublk_dev *dev,
207 		__u64 *features)
208 {
209 	struct ublk_ctrl_cmd_data data = {
210 		.cmd_op	= UBLK_U_CMD_GET_FEATURES,
211 		.flags	= CTRL_CMD_HAS_BUF,
212 		.addr = (__u64) (uintptr_t) features,
213 		.len = sizeof(*features),
214 	};
215 
216 	return __ublk_ctrl_cmd(dev, &data);
217 }
218 
219 static int ublk_ctrl_update_size(struct ublk_dev *dev,
220 		__u64 nr_sects)
221 {
222 	struct ublk_ctrl_cmd_data data = {
223 		.cmd_op	= UBLK_U_CMD_UPDATE_SIZE,
224 		.flags	= CTRL_CMD_HAS_DATA,
225 	};
226 
227 	data.data[0] = nr_sects;
228 	return __ublk_ctrl_cmd(dev, &data);
229 }
230 
231 static int ublk_ctrl_quiesce_dev(struct ublk_dev *dev,
232 				 unsigned int timeout_ms)
233 {
234 	struct ublk_ctrl_cmd_data data = {
235 		.cmd_op	= UBLK_U_CMD_QUIESCE_DEV,
236 		.flags	= CTRL_CMD_HAS_DATA,
237 	};
238 
239 	data.data[0] = timeout_ms;
240 	return __ublk_ctrl_cmd(dev, &data);
241 }
242 
243 static const char *ublk_dev_state_desc(struct ublk_dev *dev)
244 {
245 	switch (dev->dev_info.state) {
246 	case UBLK_S_DEV_DEAD:
247 		return "DEAD";
248 	case UBLK_S_DEV_LIVE:
249 		return "LIVE";
250 	case UBLK_S_DEV_QUIESCED:
251 		return "QUIESCED";
252 	default:
253 		return "UNKNOWN";
254 	};
255 }
256 
257 static void ublk_print_cpu_set(const cpu_set_t *set, char *buf, unsigned len)
258 {
259 	unsigned done = 0;
260 	int i;
261 
262 	for (i = 0; i < CPU_SETSIZE; i++) {
263 		if (CPU_ISSET(i, set))
264 			done += snprintf(&buf[done], len - done, "%d ", i);
265 	}
266 }
267 
268 static void ublk_adjust_affinity(cpu_set_t *set)
269 {
270 	int j, updated = 0;
271 
272 	/*
273 	 * Just keep the 1st CPU now.
274 	 *
275 	 * In future, auto affinity selection can be tried.
276 	 */
277 	for (j = 0; j < CPU_SETSIZE; j++) {
278 		if (CPU_ISSET(j, set)) {
279 			if (!updated) {
280 				updated = 1;
281 				continue;
282 			}
283 			CPU_CLR(j, set);
284 		}
285 	}
286 }
287 
288 /* Caller must free the allocated buffer */
289 static int ublk_ctrl_get_affinity(struct ublk_dev *ctrl_dev, cpu_set_t **ptr_buf)
290 {
291 	struct ublk_ctrl_cmd_data data = {
292 		.cmd_op	= UBLK_U_CMD_GET_QUEUE_AFFINITY,
293 		.flags	= CTRL_CMD_HAS_DATA | CTRL_CMD_HAS_BUF,
294 	};
295 	cpu_set_t *buf;
296 	int i, ret;
297 
298 	buf = malloc(sizeof(cpu_set_t) * ctrl_dev->dev_info.nr_hw_queues);
299 	if (!buf)
300 		return -ENOMEM;
301 
302 	for (i = 0; i < ctrl_dev->dev_info.nr_hw_queues; i++) {
303 		data.data[0] = i;
304 		data.len = sizeof(cpu_set_t);
305 		data.addr = (__u64)&buf[i];
306 
307 		ret = __ublk_ctrl_cmd(ctrl_dev, &data);
308 		if (ret < 0) {
309 			free(buf);
310 			return ret;
311 		}
312 		ublk_adjust_affinity(&buf[i]);
313 	}
314 
315 	*ptr_buf = buf;
316 	return 0;
317 }
318 
319 static void ublk_ctrl_dump(struct ublk_dev *dev)
320 {
321 	struct ublksrv_ctrl_dev_info *info = &dev->dev_info;
322 	struct ublk_params p;
323 	cpu_set_t *affinity;
324 	int ret;
325 
326 	ret = ublk_ctrl_get_params(dev, &p);
327 	if (ret < 0) {
328 		ublk_err("failed to get params %d %s\n", ret, strerror(-ret));
329 		return;
330 	}
331 
332 	ret = ublk_ctrl_get_affinity(dev, &affinity);
333 	if (ret < 0) {
334 		ublk_err("failed to get affinity %m\n");
335 		return;
336 	}
337 
338 	ublk_log("dev id %d: nr_hw_queues %d queue_depth %d block size %d dev_capacity %lld\n",
339 			info->dev_id, info->nr_hw_queues, info->queue_depth,
340 			1 << p.basic.logical_bs_shift, p.basic.dev_sectors);
341 	ublk_log("\tmax rq size %d daemon pid %d flags 0x%llx state %s\n",
342 			info->max_io_buf_bytes, info->ublksrv_pid, info->flags,
343 			ublk_dev_state_desc(dev));
344 
345 	if (affinity) {
346 		char buf[512];
347 		int i;
348 
349 		for (i = 0; i < info->nr_hw_queues; i++) {
350 			ublk_print_cpu_set(&affinity[i], buf, sizeof(buf));
351 			printf("\tqueue %u: affinity(%s)\n",
352 					i, buf);
353 		}
354 		free(affinity);
355 	}
356 
357 	fflush(stdout);
358 }
359 
360 static void ublk_ctrl_deinit(struct ublk_dev *dev)
361 {
362 	close(dev->ctrl_fd);
363 	free(dev);
364 }
365 
366 static struct ublk_dev *ublk_ctrl_init(void)
367 {
368 	struct ublk_dev *dev = (struct ublk_dev *)calloc(1, sizeof(*dev));
369 	struct ublksrv_ctrl_dev_info *info = &dev->dev_info;
370 	int ret;
371 
372 	dev->ctrl_fd = open(CTRL_DEV, O_RDWR);
373 	if (dev->ctrl_fd < 0) {
374 		free(dev);
375 		return NULL;
376 	}
377 
378 	info->max_io_buf_bytes = UBLK_IO_MAX_BYTES;
379 
380 	ret = ublk_setup_ring(&dev->ring, UBLK_CTRL_RING_DEPTH,
381 			UBLK_CTRL_RING_DEPTH, IORING_SETUP_SQE128);
382 	if (ret < 0) {
383 		ublk_err("queue_init: %s\n", strerror(-ret));
384 		free(dev);
385 		return NULL;
386 	}
387 	dev->nr_fds = 1;
388 
389 	return dev;
390 }
391 
392 static int __ublk_queue_cmd_buf_sz(unsigned depth)
393 {
394 	int size =  depth * sizeof(struct ublksrv_io_desc);
395 	unsigned int page_sz = getpagesize();
396 
397 	return round_up(size, page_sz);
398 }
399 
400 static int ublk_queue_max_cmd_buf_sz(void)
401 {
402 	return __ublk_queue_cmd_buf_sz(UBLK_MAX_QUEUE_DEPTH);
403 }
404 
405 static int ublk_queue_cmd_buf_sz(struct ublk_queue *q)
406 {
407 	return __ublk_queue_cmd_buf_sz(q->q_depth);
408 }
409 
410 static void ublk_queue_deinit(struct ublk_queue *q)
411 {
412 	int i;
413 	int nr_ios = q->q_depth;
414 
415 	if (q->io_cmd_buf)
416 		munmap(q->io_cmd_buf, ublk_queue_cmd_buf_sz(q));
417 
418 	for (i = 0; i < nr_ios; i++)
419 		free(q->ios[i].buf_addr);
420 }
421 
422 static void ublk_thread_deinit(struct ublk_thread *t)
423 {
424 	io_uring_unregister_buffers(&t->ring);
425 
426 	io_uring_unregister_ring_fd(&t->ring);
427 
428 	if (t->ring.ring_fd > 0) {
429 		io_uring_unregister_files(&t->ring);
430 		close(t->ring.ring_fd);
431 		t->ring.ring_fd = -1;
432 	}
433 }
434 
435 static int ublk_queue_init(struct ublk_queue *q, unsigned extra_flags)
436 {
437 	struct ublk_dev *dev = q->dev;
438 	int depth = dev->dev_info.queue_depth;
439 	int i;
440 	int cmd_buf_size, io_buf_size;
441 	unsigned long off;
442 
443 	q->tgt_ops = dev->tgt.ops;
444 	q->state = 0;
445 	q->q_depth = depth;
446 
447 	if (dev->dev_info.flags & (UBLK_F_SUPPORT_ZERO_COPY | UBLK_F_AUTO_BUF_REG)) {
448 		q->state |= UBLKSRV_NO_BUF;
449 		if (dev->dev_info.flags & UBLK_F_SUPPORT_ZERO_COPY)
450 			q->state |= UBLKSRV_ZC;
451 		if (dev->dev_info.flags & UBLK_F_AUTO_BUF_REG)
452 			q->state |= UBLKSRV_AUTO_BUF_REG;
453 	}
454 	q->state |= extra_flags;
455 
456 	cmd_buf_size = ublk_queue_cmd_buf_sz(q);
457 	off = UBLKSRV_CMD_BUF_OFFSET + q->q_id * ublk_queue_max_cmd_buf_sz();
458 	q->io_cmd_buf = mmap(0, cmd_buf_size, PROT_READ,
459 			MAP_SHARED | MAP_POPULATE, dev->fds[0], off);
460 	if (q->io_cmd_buf == MAP_FAILED) {
461 		ublk_err("ublk dev %d queue %d map io_cmd_buf failed %m\n",
462 				q->dev->dev_info.dev_id, q->q_id);
463 		goto fail;
464 	}
465 
466 	io_buf_size = dev->dev_info.max_io_buf_bytes;
467 	for (i = 0; i < q->q_depth; i++) {
468 		q->ios[i].buf_addr = NULL;
469 		q->ios[i].flags = UBLKSRV_NEED_FETCH_RQ | UBLKSRV_IO_FREE;
470 		q->ios[i].tag = i;
471 
472 		if (q->state & UBLKSRV_NO_BUF)
473 			continue;
474 
475 		if (posix_memalign((void **)&q->ios[i].buf_addr,
476 					getpagesize(), io_buf_size)) {
477 			ublk_err("ublk dev %d queue %d io %d posix_memalign failed %m\n",
478 					dev->dev_info.dev_id, q->q_id, i);
479 			goto fail;
480 		}
481 	}
482 
483 	return 0;
484  fail:
485 	ublk_queue_deinit(q);
486 	ublk_err("ublk dev %d queue %d failed\n",
487 			dev->dev_info.dev_id, q->q_id);
488 	return -ENOMEM;
489 }
490 
491 static int ublk_thread_init(struct ublk_thread *t)
492 {
493 	struct ublk_dev *dev = t->dev;
494 	int ring_depth = dev->tgt.sq_depth, cq_depth = dev->tgt.cq_depth;
495 	int ret;
496 
497 	ret = ublk_setup_ring(&t->ring, ring_depth, cq_depth,
498 			IORING_SETUP_COOP_TASKRUN |
499 			IORING_SETUP_SINGLE_ISSUER |
500 			IORING_SETUP_DEFER_TASKRUN);
501 	if (ret < 0) {
502 		ublk_err("ublk dev %d thread %d setup io_uring failed %d\n",
503 				dev->dev_info.dev_id, t->idx, ret);
504 		goto fail;
505 	}
506 
507 	if (dev->dev_info.flags & (UBLK_F_SUPPORT_ZERO_COPY | UBLK_F_AUTO_BUF_REG)) {
508 		unsigned nr_ios = dev->dev_info.queue_depth * dev->dev_info.nr_hw_queues;
509 		unsigned max_nr_ios_per_thread = nr_ios / dev->nthreads;
510 		max_nr_ios_per_thread += !!(nr_ios % dev->nthreads);
511 		ret = io_uring_register_buffers_sparse(
512 			&t->ring, max_nr_ios_per_thread);
513 		if (ret) {
514 			ublk_err("ublk dev %d thread %d register spare buffers failed %d",
515 					dev->dev_info.dev_id, t->idx, ret);
516 			goto fail;
517 		}
518 	}
519 
520 	io_uring_register_ring_fd(&t->ring);
521 
522 	ret = io_uring_register_files(&t->ring, dev->fds, dev->nr_fds);
523 	if (ret) {
524 		ublk_err("ublk dev %d thread %d register files failed %d\n",
525 				t->dev->dev_info.dev_id, t->idx, ret);
526 		goto fail;
527 	}
528 
529 	return 0;
530 fail:
531 	ublk_thread_deinit(t);
532 	ublk_err("ublk dev %d thread %d init failed\n",
533 			dev->dev_info.dev_id, t->idx);
534 	return -ENOMEM;
535 }
536 
537 #define WAIT_USEC 	100000
538 #define MAX_WAIT_USEC 	(3 * 1000000)
539 static int ublk_dev_prep(const struct dev_ctx *ctx, struct ublk_dev *dev)
540 {
541 	int dev_id = dev->dev_info.dev_id;
542 	unsigned int wait_usec = 0;
543 	int ret = 0, fd = -1;
544 	char buf[64];
545 
546 	snprintf(buf, 64, "%s%d", UBLKC_DEV, dev_id);
547 
548 	while (wait_usec < MAX_WAIT_USEC) {
549 		fd = open(buf, O_RDWR);
550 		if (fd >= 0)
551 			break;
552 		usleep(WAIT_USEC);
553 		wait_usec += WAIT_USEC;
554 	}
555 	if (fd < 0) {
556 		ublk_err("can't open %s %s\n", buf, strerror(errno));
557 		return -1;
558 	}
559 
560 	dev->fds[0] = fd;
561 	if (dev->tgt.ops->init_tgt)
562 		ret = dev->tgt.ops->init_tgt(ctx, dev);
563 	if (ret)
564 		close(dev->fds[0]);
565 	return ret;
566 }
567 
568 static void ublk_dev_unprep(struct ublk_dev *dev)
569 {
570 	if (dev->tgt.ops->deinit_tgt)
571 		dev->tgt.ops->deinit_tgt(dev);
572 	close(dev->fds[0]);
573 }
574 
575 static void ublk_set_auto_buf_reg(const struct ublk_queue *q,
576 				  struct io_uring_sqe *sqe,
577 				  unsigned short tag)
578 {
579 	struct ublk_auto_buf_reg buf = {};
580 
581 	if (q->tgt_ops->buf_index)
582 		buf.index = q->tgt_ops->buf_index(q, tag);
583 	else
584 		buf.index = q->ios[tag].buf_index;
585 
586 	if (q->state & UBLKSRV_AUTO_BUF_REG_FALLBACK)
587 		buf.flags = UBLK_AUTO_BUF_REG_FALLBACK;
588 
589 	sqe->addr = ublk_auto_buf_reg_to_sqe_addr(&buf);
590 }
591 
592 int ublk_queue_io_cmd(struct ublk_io *io)
593 {
594 	struct ublk_thread *t = io->t;
595 	struct ublk_queue *q = ublk_io_to_queue(io);
596 	struct ublksrv_io_cmd *cmd;
597 	struct io_uring_sqe *sqe[1];
598 	unsigned int cmd_op = 0;
599 	__u64 user_data;
600 
601 	/* only freed io can be issued */
602 	if (!(io->flags & UBLKSRV_IO_FREE))
603 		return 0;
604 
605 	/*
606 	 * we issue because we need either fetching or committing or
607 	 * getting data
608 	 */
609 	if (!(io->flags &
610 		(UBLKSRV_NEED_FETCH_RQ | UBLKSRV_NEED_COMMIT_RQ_COMP | UBLKSRV_NEED_GET_DATA)))
611 		return 0;
612 
613 	if (io->flags & UBLKSRV_NEED_GET_DATA)
614 		cmd_op = UBLK_U_IO_NEED_GET_DATA;
615 	else if (io->flags & UBLKSRV_NEED_COMMIT_RQ_COMP)
616 		cmd_op = UBLK_U_IO_COMMIT_AND_FETCH_REQ;
617 	else if (io->flags & UBLKSRV_NEED_FETCH_RQ)
618 		cmd_op = UBLK_U_IO_FETCH_REQ;
619 
620 	if (io_uring_sq_space_left(&t->ring) < 1)
621 		io_uring_submit(&t->ring);
622 
623 	ublk_io_alloc_sqes(io, sqe, 1);
624 	if (!sqe[0]) {
625 		ublk_err("%s: run out of sqe. thread %u, tag %d\n",
626 				__func__, t->idx, io->tag);
627 		return -1;
628 	}
629 
630 	cmd = (struct ublksrv_io_cmd *)ublk_get_sqe_cmd(sqe[0]);
631 
632 	if (cmd_op == UBLK_U_IO_COMMIT_AND_FETCH_REQ)
633 		cmd->result = io->result;
634 
635 	/* These fields should be written once, never change */
636 	ublk_set_sqe_cmd_op(sqe[0], cmd_op);
637 	sqe[0]->fd		= 0;	/* dev->fds[0] */
638 	sqe[0]->opcode	= IORING_OP_URING_CMD;
639 	sqe[0]->flags	= IOSQE_FIXED_FILE;
640 	sqe[0]->rw_flags	= 0;
641 	cmd->tag	= io->tag;
642 	cmd->q_id	= q->q_id;
643 	if (!(q->state & UBLKSRV_NO_BUF))
644 		cmd->addr	= (__u64) (uintptr_t) io->buf_addr;
645 	else
646 		cmd->addr	= 0;
647 
648 	if (q->state & UBLKSRV_AUTO_BUF_REG)
649 		ublk_set_auto_buf_reg(q, sqe[0], io->tag);
650 
651 	user_data = build_user_data(io->tag, _IOC_NR(cmd_op), 0, q->q_id, 0);
652 	io_uring_sqe_set_data64(sqe[0], user_data);
653 
654 	io->flags = 0;
655 
656 	t->cmd_inflight += 1;
657 
658 	ublk_dbg(UBLK_DBG_IO_CMD, "%s: (thread %u qid %d tag %u cmd_op %u) iof %x stopping %d\n",
659 			__func__, t->idx, q->q_id, io->tag, cmd_op,
660 			io->flags, !!(t->state & UBLKSRV_THREAD_STOPPING));
661 	return 1;
662 }
663 
664 static void ublk_submit_fetch_commands(struct ublk_thread *t)
665 {
666 	struct ublk_queue *q;
667 	struct ublk_io *io;
668 	int i = 0, j = 0;
669 
670 	if (t->dev->per_io_tasks) {
671 		/*
672 		 * Lexicographically order all the (qid,tag) pairs, with
673 		 * qid taking priority (so (1,0) > (0,1)). Then make
674 		 * this thread the daemon for every Nth entry in this
675 		 * list (N is the number of threads), starting at this
676 		 * thread's index. This ensures that each queue is
677 		 * handled by as many ublk server threads as possible,
678 		 * so that load that is concentrated on one or a few
679 		 * queues can make use of all ublk server threads.
680 		 */
681 		const struct ublksrv_ctrl_dev_info *dinfo = &t->dev->dev_info;
682 		int nr_ios = dinfo->nr_hw_queues * dinfo->queue_depth;
683 		for (i = t->idx; i < nr_ios; i += t->dev->nthreads) {
684 			int q_id = i / dinfo->queue_depth;
685 			int tag = i % dinfo->queue_depth;
686 			q = &t->dev->q[q_id];
687 			io = &q->ios[tag];
688 			io->t = t;
689 			io->buf_index = j++;
690 			ublk_queue_io_cmd(io);
691 		}
692 	} else {
693 		/*
694 		 * Service exclusively the queue whose q_id matches our
695 		 * thread index.
696 		 */
697 		struct ublk_queue *q = &t->dev->q[t->idx];
698 		for (i = 0; i < q->q_depth; i++) {
699 			io = &q->ios[i];
700 			io->t = t;
701 			io->buf_index = i;
702 			ublk_queue_io_cmd(io);
703 		}
704 	}
705 }
706 
707 static int ublk_thread_is_idle(struct ublk_thread *t)
708 {
709 	return !io_uring_sq_ready(&t->ring) && !t->io_inflight;
710 }
711 
712 static int ublk_thread_is_done(struct ublk_thread *t)
713 {
714 	return (t->state & UBLKSRV_THREAD_STOPPING) && ublk_thread_is_idle(t);
715 }
716 
717 static inline void ublksrv_handle_tgt_cqe(struct ublk_queue *q,
718 		struct io_uring_cqe *cqe)
719 {
720 	unsigned tag = user_data_to_tag(cqe->user_data);
721 
722 	if (cqe->res < 0 && cqe->res != -EAGAIN)
723 		ublk_err("%s: failed tgt io: res %d qid %u tag %u, cmd_op %u\n",
724 			__func__, cqe->res, q->q_id,
725 			user_data_to_tag(cqe->user_data),
726 			user_data_to_op(cqe->user_data));
727 
728 	if (q->tgt_ops->tgt_io_done)
729 		q->tgt_ops->tgt_io_done(q, tag, cqe);
730 }
731 
732 static void ublk_handle_cqe(struct ublk_thread *t,
733 		struct io_uring_cqe *cqe, void *data)
734 {
735 	struct ublk_dev *dev = t->dev;
736 	unsigned q_id = user_data_to_q_id(cqe->user_data);
737 	struct ublk_queue *q = &dev->q[q_id];
738 	unsigned tag = user_data_to_tag(cqe->user_data);
739 	unsigned cmd_op = user_data_to_op(cqe->user_data);
740 	int fetch = (cqe->res != UBLK_IO_RES_ABORT) &&
741 		!(t->state & UBLKSRV_THREAD_STOPPING);
742 	struct ublk_io *io;
743 
744 	if (cqe->res < 0 && cqe->res != -ENODEV)
745 		ublk_err("%s: res %d userdata %llx queue state %x\n", __func__,
746 				cqe->res, cqe->user_data, q->state);
747 
748 	ublk_dbg(UBLK_DBG_IO_CMD, "%s: res %d (qid %d tag %u cmd_op %u target %d/%d) stopping %d\n",
749 			__func__, cqe->res, q->q_id, tag, cmd_op,
750 			is_target_io(cqe->user_data),
751 			user_data_to_tgt_data(cqe->user_data),
752 			(t->state & UBLKSRV_THREAD_STOPPING));
753 
754 	/* Don't retrieve io in case of target io */
755 	if (is_target_io(cqe->user_data)) {
756 		ublksrv_handle_tgt_cqe(q, cqe);
757 		return;
758 	}
759 
760 	io = &q->ios[tag];
761 	t->cmd_inflight--;
762 
763 	if (!fetch) {
764 		t->state |= UBLKSRV_THREAD_STOPPING;
765 		io->flags &= ~UBLKSRV_NEED_FETCH_RQ;
766 	}
767 
768 	if (cqe->res == UBLK_IO_RES_OK) {
769 		assert(tag < q->q_depth);
770 		if (q->tgt_ops->queue_io)
771 			q->tgt_ops->queue_io(q, tag);
772 	} else if (cqe->res == UBLK_IO_RES_NEED_GET_DATA) {
773 		io->flags |= UBLKSRV_NEED_GET_DATA | UBLKSRV_IO_FREE;
774 		ublk_queue_io_cmd(io);
775 	} else {
776 		/*
777 		 * COMMIT_REQ will be completed immediately since no fetching
778 		 * piggyback is required.
779 		 *
780 		 * Marking IO_FREE only, then this io won't be issued since
781 		 * we only issue io with (UBLKSRV_IO_FREE | UBLKSRV_NEED_*)
782 		 *
783 		 * */
784 		io->flags = UBLKSRV_IO_FREE;
785 	}
786 }
787 
788 static int ublk_reap_events_uring(struct ublk_thread *t)
789 {
790 	struct io_uring_cqe *cqe;
791 	unsigned head;
792 	int count = 0;
793 
794 	io_uring_for_each_cqe(&t->ring, head, cqe) {
795 		ublk_handle_cqe(t, cqe, NULL);
796 		count += 1;
797 	}
798 	io_uring_cq_advance(&t->ring, count);
799 
800 	return count;
801 }
802 
803 static int ublk_process_io(struct ublk_thread *t)
804 {
805 	int ret, reapped;
806 
807 	ublk_dbg(UBLK_DBG_THREAD, "dev%d-t%u: to_submit %d inflight cmd %u stopping %d\n",
808 				t->dev->dev_info.dev_id,
809 				t->idx, io_uring_sq_ready(&t->ring),
810 				t->cmd_inflight,
811 				(t->state & UBLKSRV_THREAD_STOPPING));
812 
813 	if (ublk_thread_is_done(t))
814 		return -ENODEV;
815 
816 	ret = io_uring_submit_and_wait(&t->ring, 1);
817 	reapped = ublk_reap_events_uring(t);
818 
819 	ublk_dbg(UBLK_DBG_THREAD, "submit result %d, reapped %d stop %d idle %d\n",
820 			ret, reapped, (t->state & UBLKSRV_THREAD_STOPPING),
821 			(t->state & UBLKSRV_THREAD_IDLE));
822 
823 	return reapped;
824 }
825 
826 static void ublk_thread_set_sched_affinity(const struct ublk_thread *t,
827 		cpu_set_t *cpuset)
828 {
829         if (sched_setaffinity(0, sizeof(*cpuset), cpuset) < 0)
830 		ublk_err("ublk dev %u thread %u set affinity failed",
831 				t->dev->dev_info.dev_id, t->idx);
832 }
833 
834 struct ublk_thread_info {
835 	struct ublk_dev 	*dev;
836 	unsigned		idx;
837 	sem_t 			*ready;
838 	cpu_set_t 		*affinity;
839 };
840 
841 static void *ublk_io_handler_fn(void *data)
842 {
843 	struct ublk_thread_info *info = data;
844 	struct ublk_thread *t = &info->dev->threads[info->idx];
845 	int dev_id = info->dev->dev_info.dev_id;
846 	int ret;
847 
848 	t->dev = info->dev;
849 	t->idx = info->idx;
850 
851 	ret = ublk_thread_init(t);
852 	if (ret) {
853 		ublk_err("ublk dev %d thread %u init failed\n",
854 				dev_id, t->idx);
855 		return NULL;
856 	}
857 	/* IO perf is sensitive with queue pthread affinity on NUMA machine*/
858 	if (info->affinity)
859 		ublk_thread_set_sched_affinity(t, info->affinity);
860 	sem_post(info->ready);
861 
862 	ublk_dbg(UBLK_DBG_THREAD, "tid %d: ublk dev %d thread %u started\n",
863 			gettid(), dev_id, t->idx);
864 
865 	/* submit all io commands to ublk driver */
866 	ublk_submit_fetch_commands(t);
867 	do {
868 		if (ublk_process_io(t) < 0)
869 			break;
870 	} while (1);
871 
872 	ublk_dbg(UBLK_DBG_THREAD, "tid %d: ublk dev %d thread %d exiting\n",
873 		 gettid(), dev_id, t->idx);
874 	ublk_thread_deinit(t);
875 	return NULL;
876 }
877 
878 static void ublk_set_parameters(struct ublk_dev *dev)
879 {
880 	int ret;
881 
882 	ret = ublk_ctrl_set_params(dev, &dev->tgt.params);
883 	if (ret)
884 		ublk_err("dev %d set basic parameter failed %d\n",
885 				dev->dev_info.dev_id, ret);
886 }
887 
888 static int ublk_send_dev_event(const struct dev_ctx *ctx, struct ublk_dev *dev, int dev_id)
889 {
890 	uint64_t id;
891 	int evtfd = ctx->_evtfd;
892 
893 	if (evtfd < 0)
894 		return -EBADF;
895 
896 	if (dev_id >= 0)
897 		id = dev_id + 1;
898 	else
899 		id = ERROR_EVTFD_DEVID;
900 
901 	if (dev && ctx->shadow_dev)
902 		memcpy(&ctx->shadow_dev->q, &dev->q, sizeof(dev->q));
903 
904 	if (write(evtfd, &id, sizeof(id)) != sizeof(id))
905 		return -EINVAL;
906 
907 	close(evtfd);
908 	shmdt(ctx->shadow_dev);
909 
910 	return 0;
911 }
912 
913 
914 static int ublk_start_daemon(const struct dev_ctx *ctx, struct ublk_dev *dev)
915 {
916 	const struct ublksrv_ctrl_dev_info *dinfo = &dev->dev_info;
917 	struct ublk_thread_info *tinfo;
918 	unsigned extra_flags = 0;
919 	cpu_set_t *affinity_buf;
920 	void *thread_ret;
921 	sem_t ready;
922 	int ret, i;
923 
924 	ublk_dbg(UBLK_DBG_DEV, "%s enter\n", __func__);
925 
926 	tinfo = calloc(sizeof(struct ublk_thread_info), dev->nthreads);
927 	if (!tinfo)
928 		return -ENOMEM;
929 
930 	sem_init(&ready, 0, 0);
931 	ret = ublk_dev_prep(ctx, dev);
932 	if (ret)
933 		return ret;
934 
935 	ret = ublk_ctrl_get_affinity(dev, &affinity_buf);
936 	if (ret)
937 		return ret;
938 
939 	if (ctx->auto_zc_fallback)
940 		extra_flags = UBLKSRV_AUTO_BUF_REG_FALLBACK;
941 
942 	for (i = 0; i < dinfo->nr_hw_queues; i++) {
943 		dev->q[i].dev = dev;
944 		dev->q[i].q_id = i;
945 
946 		ret = ublk_queue_init(&dev->q[i], extra_flags);
947 		if (ret) {
948 			ublk_err("ublk dev %d queue %d init queue failed\n",
949 				 dinfo->dev_id, i);
950 			goto fail;
951 		}
952 	}
953 
954 	for (i = 0; i < dev->nthreads; i++) {
955 		tinfo[i].dev = dev;
956 		tinfo[i].idx = i;
957 		tinfo[i].ready = &ready;
958 
959 		/*
960 		 * If threads are not tied 1:1 to queues, setting thread
961 		 * affinity based on queue affinity makes little sense.
962 		 * However, thread CPU affinity has significant impact
963 		 * on performance, so to compare fairly, we'll still set
964 		 * thread CPU affinity based on queue affinity where
965 		 * possible.
966 		 */
967 		if (dev->nthreads == dinfo->nr_hw_queues)
968 			tinfo[i].affinity = &affinity_buf[i];
969 		pthread_create(&dev->threads[i].thread, NULL,
970 				ublk_io_handler_fn,
971 				&tinfo[i]);
972 	}
973 
974 	for (i = 0; i < dev->nthreads; i++)
975 		sem_wait(&ready);
976 	free(tinfo);
977 	free(affinity_buf);
978 
979 	/* everything is fine now, start us */
980 	if (ctx->recovery)
981 		ret = ublk_ctrl_end_user_recovery(dev, getpid());
982 	else {
983 		ublk_set_parameters(dev);
984 		ret = ublk_ctrl_start_dev(dev, getpid());
985 	}
986 	if (ret < 0) {
987 		ublk_err("%s: ublk_ctrl_start_dev failed: %d\n", __func__, ret);
988 		goto fail;
989 	}
990 
991 	ublk_ctrl_get_info(dev);
992 	if (ctx->fg)
993 		ublk_ctrl_dump(dev);
994 	else
995 		ublk_send_dev_event(ctx, dev, dev->dev_info.dev_id);
996 
997 	/* wait until we are terminated */
998 	for (i = 0; i < dev->nthreads; i++)
999 		pthread_join(dev->threads[i].thread, &thread_ret);
1000  fail:
1001 	for (i = 0; i < dinfo->nr_hw_queues; i++)
1002 		ublk_queue_deinit(&dev->q[i]);
1003 	ublk_dev_unprep(dev);
1004 	ublk_dbg(UBLK_DBG_DEV, "%s exit\n", __func__);
1005 
1006 	return ret;
1007 }
1008 
1009 static int wait_ublk_dev(const char *path, int evt_mask, unsigned timeout)
1010 {
1011 #define EV_SIZE (sizeof(struct inotify_event))
1012 #define EV_BUF_LEN (128 * (EV_SIZE + 16))
1013 	struct pollfd pfd;
1014 	int fd, wd;
1015 	int ret = -EINVAL;
1016 	const char *dev_name = basename(path);
1017 
1018 	fd = inotify_init();
1019 	if (fd < 0) {
1020 		ublk_dbg(UBLK_DBG_DEV, "%s: inotify init failed\n", __func__);
1021 		return fd;
1022 	}
1023 
1024 	wd = inotify_add_watch(fd, "/dev", evt_mask);
1025 	if (wd == -1) {
1026 		ublk_dbg(UBLK_DBG_DEV, "%s: add watch for /dev failed\n", __func__);
1027 		goto fail;
1028 	}
1029 
1030 	pfd.fd = fd;
1031 	pfd.events = POLL_IN;
1032 	while (1) {
1033 		int i = 0;
1034 		char buffer[EV_BUF_LEN];
1035 		ret = poll(&pfd, 1, 1000 * timeout);
1036 
1037 		if (ret == -1) {
1038 			ublk_err("%s: poll inotify failed: %d\n", __func__, ret);
1039 			goto rm_watch;
1040 		} else if (ret == 0) {
1041 			ublk_err("%s: poll inotify timeout\n", __func__);
1042 			ret = -ETIMEDOUT;
1043 			goto rm_watch;
1044 		}
1045 
1046 		ret = read(fd, buffer, EV_BUF_LEN);
1047 		if (ret < 0) {
1048 			ublk_err("%s: read inotify fd failed\n", __func__);
1049 			goto rm_watch;
1050 		}
1051 
1052 		while (i < ret) {
1053 			struct inotify_event *event = (struct inotify_event *)&buffer[i];
1054 
1055 			ublk_dbg(UBLK_DBG_DEV, "%s: inotify event %x %s\n",
1056 					__func__, event->mask, event->name);
1057 			if (event->mask & evt_mask) {
1058 				if (!strcmp(event->name, dev_name)) {
1059 					ret = 0;
1060 					goto rm_watch;
1061 				}
1062 			}
1063 			i += EV_SIZE + event->len;
1064 		}
1065 	}
1066 rm_watch:
1067 	inotify_rm_watch(fd, wd);
1068 fail:
1069 	close(fd);
1070 	return ret;
1071 }
1072 
1073 static int ublk_stop_io_daemon(const struct ublk_dev *dev)
1074 {
1075 	int daemon_pid = dev->dev_info.ublksrv_pid;
1076 	int dev_id = dev->dev_info.dev_id;
1077 	char ublkc[64];
1078 	int ret = 0;
1079 
1080 	if (daemon_pid < 0)
1081 		return 0;
1082 
1083 	/* daemon may be dead already */
1084 	if (kill(daemon_pid, 0) < 0)
1085 		goto wait;
1086 
1087 	snprintf(ublkc, sizeof(ublkc), "/dev/%s%d", "ublkc", dev_id);
1088 
1089 	/* ublk char device may be gone already */
1090 	if (access(ublkc, F_OK) != 0)
1091 		goto wait;
1092 
1093 	/* Wait until ublk char device is closed, when the daemon is shutdown */
1094 	ret = wait_ublk_dev(ublkc, IN_CLOSE, 10);
1095 	/* double check and since it may be closed before starting inotify */
1096 	if (ret == -ETIMEDOUT)
1097 		ret = kill(daemon_pid, 0) < 0;
1098 wait:
1099 	waitpid(daemon_pid, NULL, 0);
1100 	ublk_dbg(UBLK_DBG_DEV, "%s: pid %d dev_id %d ret %d\n",
1101 			__func__, daemon_pid, dev_id, ret);
1102 
1103 	return ret;
1104 }
1105 
1106 static int __cmd_dev_add(const struct dev_ctx *ctx)
1107 {
1108 	unsigned nthreads = ctx->nthreads;
1109 	unsigned nr_queues = ctx->nr_hw_queues;
1110 	const char *tgt_type = ctx->tgt_type;
1111 	unsigned depth = ctx->queue_depth;
1112 	__u64 features;
1113 	const struct ublk_tgt_ops *ops;
1114 	struct ublksrv_ctrl_dev_info *info;
1115 	struct ublk_dev *dev = NULL;
1116 	int dev_id = ctx->dev_id;
1117 	int ret, i;
1118 
1119 	ops = ublk_find_tgt(tgt_type);
1120 	if (!ops) {
1121 		ublk_err("%s: no such tgt type, type %s\n",
1122 				__func__, tgt_type);
1123 		ret = -ENODEV;
1124 		goto fail;
1125 	}
1126 
1127 	if (nr_queues > UBLK_MAX_QUEUES || depth > UBLK_QUEUE_DEPTH) {
1128 		ublk_err("%s: invalid nr_queues or depth queues %u depth %u\n",
1129 				__func__, nr_queues, depth);
1130 		ret = -EINVAL;
1131 		goto fail;
1132 	}
1133 
1134 	/* default to 1:1 threads:queues if nthreads is unspecified */
1135 	if (!nthreads)
1136 		nthreads = nr_queues;
1137 
1138 	if (nthreads > UBLK_MAX_THREADS) {
1139 		ublk_err("%s: %u is too many threads (max %u)\n",
1140 				__func__, nthreads, UBLK_MAX_THREADS);
1141 		ret = -EINVAL;
1142 		goto fail;
1143 	}
1144 
1145 	if (nthreads != nr_queues && !ctx->per_io_tasks) {
1146 		ublk_err("%s: threads %u must be same as queues %u if "
1147 			"not using per_io_tasks\n",
1148 			__func__, nthreads, nr_queues);
1149 		ret = -EINVAL;
1150 		goto fail;
1151 	}
1152 
1153 	dev = ublk_ctrl_init();
1154 	if (!dev) {
1155 		ublk_err("%s: can't alloc dev id %d, type %s\n",
1156 				__func__, dev_id, tgt_type);
1157 		ret = -ENOMEM;
1158 		goto fail;
1159 	}
1160 
1161 	/* kernel doesn't support get_features */
1162 	ret = ublk_ctrl_get_features(dev, &features);
1163 	if (ret < 0) {
1164 		ret = -EINVAL;
1165 		goto fail;
1166 	}
1167 
1168 	if (!(features & UBLK_F_CMD_IOCTL_ENCODE)) {
1169 		ret = -ENOTSUP;
1170 		goto fail;
1171 	}
1172 
1173 	info = &dev->dev_info;
1174 	info->dev_id = ctx->dev_id;
1175 	info->nr_hw_queues = nr_queues;
1176 	info->queue_depth = depth;
1177 	info->flags = ctx->flags;
1178 	if ((features & UBLK_F_QUIESCE) &&
1179 			(info->flags & UBLK_F_USER_RECOVERY))
1180 		info->flags |= UBLK_F_QUIESCE;
1181 	dev->nthreads = nthreads;
1182 	dev->per_io_tasks = ctx->per_io_tasks;
1183 	dev->tgt.ops = ops;
1184 	dev->tgt.sq_depth = depth;
1185 	dev->tgt.cq_depth = depth;
1186 
1187 	for (i = 0; i < MAX_BACK_FILES; i++) {
1188 		if (ctx->files[i]) {
1189 			strcpy(dev->tgt.backing_file[i], ctx->files[i]);
1190 			dev->tgt.nr_backing_files++;
1191 		}
1192 	}
1193 
1194 	if (ctx->recovery)
1195 		ret = ublk_ctrl_start_user_recovery(dev);
1196 	else
1197 		ret = ublk_ctrl_add_dev(dev);
1198 	if (ret < 0) {
1199 		ublk_err("%s: can't add dev id %d, type %s ret %d\n",
1200 				__func__, dev_id, tgt_type, ret);
1201 		goto fail;
1202 	}
1203 
1204 	ret = ublk_start_daemon(ctx, dev);
1205 	ublk_dbg(UBLK_DBG_DEV, "%s: daemon exit %d\b", ret);
1206 	if (ret < 0)
1207 		ublk_ctrl_del_dev(dev);
1208 
1209 fail:
1210 	if (ret < 0)
1211 		ublk_send_dev_event(ctx, dev, -1);
1212 	if (dev)
1213 		ublk_ctrl_deinit(dev);
1214 	return ret;
1215 }
1216 
1217 static int __cmd_dev_list(struct dev_ctx *ctx);
1218 
1219 static int cmd_dev_add(struct dev_ctx *ctx)
1220 {
1221 	int res;
1222 
1223 	if (ctx->fg)
1224 		goto run;
1225 
1226 	ctx->_shmid = shmget(IPC_PRIVATE, sizeof(struct ublk_dev), IPC_CREAT | 0666);
1227 	if (ctx->_shmid < 0) {
1228 		ublk_err("%s: failed to shmget %s\n", __func__, strerror(errno));
1229 		exit(-1);
1230 	}
1231 	ctx->shadow_dev = (struct ublk_dev *)shmat(ctx->_shmid, NULL, 0);
1232 	if (ctx->shadow_dev == (struct ublk_dev *)-1) {
1233 		ublk_err("%s: failed to shmat %s\n", __func__, strerror(errno));
1234 		exit(-1);
1235 	}
1236 	ctx->_evtfd = eventfd(0, 0);
1237 	if (ctx->_evtfd < 0) {
1238 		ublk_err("%s: failed to create eventfd %s\n", __func__, strerror(errno));
1239 		exit(-1);
1240 	}
1241 
1242 	res = fork();
1243 	if (res == 0) {
1244 		int res2;
1245 
1246 		setsid();
1247 		res2 = fork();
1248 		if (res2 == 0) {
1249 			/* prepare for detaching */
1250 			close(STDIN_FILENO);
1251 			close(STDOUT_FILENO);
1252 			close(STDERR_FILENO);
1253 run:
1254 			res = __cmd_dev_add(ctx);
1255 			return res;
1256 		} else {
1257 			/* detached from the foreground task */
1258 			exit(EXIT_SUCCESS);
1259 		}
1260 	} else if (res > 0) {
1261 		uint64_t id;
1262 		int exit_code = EXIT_FAILURE;
1263 
1264 		res = read(ctx->_evtfd, &id, sizeof(id));
1265 		close(ctx->_evtfd);
1266 		if (res == sizeof(id) && id != ERROR_EVTFD_DEVID) {
1267 			ctx->dev_id = id - 1;
1268 			if (__cmd_dev_list(ctx) >= 0)
1269 				exit_code = EXIT_SUCCESS;
1270 		}
1271 		shmdt(ctx->shadow_dev);
1272 		shmctl(ctx->_shmid, IPC_RMID, NULL);
1273 		/* wait for child and detach from it */
1274 		wait(NULL);
1275 		if (exit_code == EXIT_FAILURE)
1276 			ublk_err("%s: command failed\n", __func__);
1277 		exit(exit_code);
1278 	} else {
1279 		exit(EXIT_FAILURE);
1280 	}
1281 }
1282 
1283 static int __cmd_dev_del(struct dev_ctx *ctx)
1284 {
1285 	int number = ctx->dev_id;
1286 	struct ublk_dev *dev;
1287 	int ret;
1288 
1289 	dev = ublk_ctrl_init();
1290 	dev->dev_info.dev_id = number;
1291 
1292 	ret = ublk_ctrl_get_info(dev);
1293 	if (ret < 0)
1294 		goto fail;
1295 
1296 	ret = ublk_ctrl_stop_dev(dev);
1297 	if (ret < 0)
1298 		ublk_err("%s: stop dev %d failed ret %d\n", __func__, number, ret);
1299 
1300 	ret = ublk_stop_io_daemon(dev);
1301 	if (ret < 0)
1302 		ublk_err("%s: stop daemon id %d dev %d, ret %d\n",
1303 				__func__, dev->dev_info.ublksrv_pid, number, ret);
1304 	ublk_ctrl_del_dev(dev);
1305 fail:
1306 	ublk_ctrl_deinit(dev);
1307 
1308 	return (ret >= 0) ? 0 : ret;
1309 }
1310 
1311 static int cmd_dev_del(struct dev_ctx *ctx)
1312 {
1313 	int i;
1314 
1315 	if (ctx->dev_id >= 0 || !ctx->all)
1316 		return __cmd_dev_del(ctx);
1317 
1318 	for (i = 0; i < 255; i++) {
1319 		ctx->dev_id = i;
1320 		__cmd_dev_del(ctx);
1321 	}
1322 	return 0;
1323 }
1324 
1325 static int __cmd_dev_list(struct dev_ctx *ctx)
1326 {
1327 	struct ublk_dev *dev = ublk_ctrl_init();
1328 	int ret;
1329 
1330 	if (!dev)
1331 		return -ENODEV;
1332 
1333 	dev->dev_info.dev_id = ctx->dev_id;
1334 
1335 	ret = ublk_ctrl_get_info(dev);
1336 	if (ret < 0) {
1337 		if (ctx->logging)
1338 			ublk_err("%s: can't get dev info from %d: %d\n",
1339 					__func__, ctx->dev_id, ret);
1340 	} else {
1341 		if (ctx->shadow_dev)
1342 			memcpy(&dev->q, ctx->shadow_dev->q, sizeof(dev->q));
1343 
1344 		ublk_ctrl_dump(dev);
1345 	}
1346 
1347 	ublk_ctrl_deinit(dev);
1348 
1349 	return ret;
1350 }
1351 
1352 static int cmd_dev_list(struct dev_ctx *ctx)
1353 {
1354 	int i;
1355 
1356 	if (ctx->dev_id >= 0 || !ctx->all)
1357 		return __cmd_dev_list(ctx);
1358 
1359 	ctx->logging = false;
1360 	for (i = 0; i < 255; i++) {
1361 		ctx->dev_id = i;
1362 		__cmd_dev_list(ctx);
1363 	}
1364 	return 0;
1365 }
1366 
1367 static int cmd_dev_get_features(void)
1368 {
1369 #define const_ilog2(x) (63 - __builtin_clzll(x))
1370 	static const char *feat_map[] = {
1371 		[const_ilog2(UBLK_F_SUPPORT_ZERO_COPY)] = "ZERO_COPY",
1372 		[const_ilog2(UBLK_F_URING_CMD_COMP_IN_TASK)] = "COMP_IN_TASK",
1373 		[const_ilog2(UBLK_F_NEED_GET_DATA)] = "GET_DATA",
1374 		[const_ilog2(UBLK_F_USER_RECOVERY)] = "USER_RECOVERY",
1375 		[const_ilog2(UBLK_F_USER_RECOVERY_REISSUE)] = "RECOVERY_REISSUE",
1376 		[const_ilog2(UBLK_F_UNPRIVILEGED_DEV)] = "UNPRIVILEGED_DEV",
1377 		[const_ilog2(UBLK_F_CMD_IOCTL_ENCODE)] = "CMD_IOCTL_ENCODE",
1378 		[const_ilog2(UBLK_F_USER_COPY)] = "USER_COPY",
1379 		[const_ilog2(UBLK_F_ZONED)] = "ZONED",
1380 		[const_ilog2(UBLK_F_USER_RECOVERY_FAIL_IO)] = "RECOVERY_FAIL_IO",
1381 		[const_ilog2(UBLK_F_UPDATE_SIZE)] = "UPDATE_SIZE",
1382 		[const_ilog2(UBLK_F_AUTO_BUF_REG)] = "AUTO_BUF_REG",
1383 		[const_ilog2(UBLK_F_QUIESCE)] = "QUIESCE",
1384 		[const_ilog2(UBLK_F_PER_IO_DAEMON)] = "PER_IO_DAEMON",
1385 	};
1386 	struct ublk_dev *dev;
1387 	__u64 features = 0;
1388 	int ret;
1389 
1390 	dev = ublk_ctrl_init();
1391 	if (!dev) {
1392 		fprintf(stderr, "ublksrv_ctrl_init failed id\n");
1393 		return -EOPNOTSUPP;
1394 	}
1395 
1396 	ret = ublk_ctrl_get_features(dev, &features);
1397 	if (!ret) {
1398 		int i;
1399 
1400 		printf("ublk_drv features: 0x%llx\n", features);
1401 
1402 		for (i = 0; i < sizeof(features) * 8; i++) {
1403 			const char *feat;
1404 
1405 			if (!((1ULL << i)  & features))
1406 				continue;
1407 			if (i < sizeof(feat_map) / sizeof(feat_map[0]))
1408 				feat = feat_map[i];
1409 			else
1410 				feat = "unknown";
1411 			printf("\t%-20s: 0x%llx\n", feat, 1ULL << i);
1412 		}
1413 	}
1414 
1415 	return ret;
1416 }
1417 
1418 static int cmd_dev_update_size(struct dev_ctx *ctx)
1419 {
1420 	struct ublk_dev *dev = ublk_ctrl_init();
1421 	struct ublk_params p;
1422 	int ret = -EINVAL;
1423 
1424 	if (!dev)
1425 		return -ENODEV;
1426 
1427 	if (ctx->dev_id < 0) {
1428 		fprintf(stderr, "device id isn't provided\n");
1429 		goto out;
1430 	}
1431 
1432 	dev->dev_info.dev_id = ctx->dev_id;
1433 	ret = ublk_ctrl_get_params(dev, &p);
1434 	if (ret < 0) {
1435 		ublk_err("failed to get params %d %s\n", ret, strerror(-ret));
1436 		goto out;
1437 	}
1438 
1439 	if (ctx->size & ((1 << p.basic.logical_bs_shift) - 1)) {
1440 		ublk_err("size isn't aligned with logical block size\n");
1441 		ret = -EINVAL;
1442 		goto out;
1443 	}
1444 
1445 	ret = ublk_ctrl_update_size(dev, ctx->size >> 9);
1446 out:
1447 	ublk_ctrl_deinit(dev);
1448 	return ret;
1449 }
1450 
1451 static int cmd_dev_quiesce(struct dev_ctx *ctx)
1452 {
1453 	struct ublk_dev *dev = ublk_ctrl_init();
1454 	int ret = -EINVAL;
1455 
1456 	if (!dev)
1457 		return -ENODEV;
1458 
1459 	if (ctx->dev_id < 0) {
1460 		fprintf(stderr, "device id isn't provided for quiesce\n");
1461 		goto out;
1462 	}
1463 	dev->dev_info.dev_id = ctx->dev_id;
1464 	ret = ublk_ctrl_quiesce_dev(dev, 10000);
1465 
1466 out:
1467 	ublk_ctrl_deinit(dev);
1468 	return ret;
1469 }
1470 
1471 static void __cmd_create_help(char *exe, bool recovery)
1472 {
1473 	int i;
1474 
1475 	printf("%s %s -t [null|loop|stripe|fault_inject] [-q nr_queues] [-d depth] [-n dev_id]\n",
1476 			exe, recovery ? "recover" : "add");
1477 	printf("\t[--foreground] [--quiet] [-z] [--auto_zc] [--auto_zc_fallback] [--debug_mask mask] [-r 0|1 ] [-g]\n");
1478 	printf("\t[-e 0|1 ] [-i 0|1]\n");
1479 	printf("\t[--nthreads threads] [--per_io_tasks]\n");
1480 	printf("\t[target options] [backfile1] [backfile2] ...\n");
1481 	printf("\tdefault: nr_queues=2(max 32), depth=128(max 1024), dev_id=-1(auto allocation)\n");
1482 	printf("\tdefault: nthreads=nr_queues");
1483 
1484 	for (i = 0; i < sizeof(tgt_ops_list) / sizeof(tgt_ops_list[0]); i++) {
1485 		const struct ublk_tgt_ops *ops = tgt_ops_list[i];
1486 
1487 		if (ops->usage)
1488 			ops->usage(ops);
1489 	}
1490 }
1491 
1492 static void cmd_add_help(char *exe)
1493 {
1494 	__cmd_create_help(exe, false);
1495 	printf("\n");
1496 }
1497 
1498 static void cmd_recover_help(char *exe)
1499 {
1500 	__cmd_create_help(exe, true);
1501 	printf("\tPlease provide exact command line for creating this device with real dev_id\n");
1502 	printf("\n");
1503 }
1504 
1505 static int cmd_dev_help(char *exe)
1506 {
1507 	cmd_add_help(exe);
1508 	cmd_recover_help(exe);
1509 
1510 	printf("%s del [-n dev_id] -a \n", exe);
1511 	printf("\t -a delete all devices -n delete specified device\n\n");
1512 	printf("%s list [-n dev_id] -a \n", exe);
1513 	printf("\t -a list all devices, -n list specified device, default -a \n\n");
1514 	printf("%s features\n", exe);
1515 	printf("%s update_size -n dev_id -s|--size size_in_bytes \n", exe);
1516 	printf("%s quiesce -n dev_id\n", exe);
1517 	return 0;
1518 }
1519 
1520 int main(int argc, char *argv[])
1521 {
1522 	static const struct option longopts[] = {
1523 		{ "all",		0,	NULL, 'a' },
1524 		{ "type",		1,	NULL, 't' },
1525 		{ "number",		1,	NULL, 'n' },
1526 		{ "queues",		1,	NULL, 'q' },
1527 		{ "depth",		1,	NULL, 'd' },
1528 		{ "debug_mask",		1,	NULL,  0  },
1529 		{ "quiet",		0,	NULL,  0  },
1530 		{ "zero_copy",          0,      NULL, 'z' },
1531 		{ "foreground",		0,	NULL,  0  },
1532 		{ "recovery", 		1,      NULL, 'r' },
1533 		{ "recovery_fail_io",	1,	NULL, 'e'},
1534 		{ "recovery_reissue",	1,	NULL, 'i'},
1535 		{ "get_data",		1,	NULL, 'g'},
1536 		{ "auto_zc",		0,	NULL,  0 },
1537 		{ "auto_zc_fallback", 	0,	NULL,  0 },
1538 		{ "size",		1,	NULL, 's'},
1539 		{ "nthreads",		1,	NULL,  0 },
1540 		{ "per_io_tasks",	0,	NULL,  0 },
1541 		{ 0, 0, 0, 0 }
1542 	};
1543 	const struct ublk_tgt_ops *ops = NULL;
1544 	int option_idx, opt;
1545 	const char *cmd = argv[1];
1546 	struct dev_ctx ctx = {
1547 		.queue_depth	=	128,
1548 		.nr_hw_queues	=	2,
1549 		.dev_id		=	-1,
1550 		.tgt_type	=	"unknown",
1551 	};
1552 	int ret = -EINVAL, i;
1553 	int tgt_argc = 1;
1554 	char *tgt_argv[MAX_NR_TGT_ARG] = { NULL };
1555 	int value;
1556 
1557 	if (argc == 1)
1558 		return ret;
1559 
1560 	opterr = 0;
1561 	optind = 2;
1562 	while ((opt = getopt_long(argc, argv, "t:n:d:q:r:e:i:s:gaz",
1563 				  longopts, &option_idx)) != -1) {
1564 		switch (opt) {
1565 		case 'a':
1566 			ctx.all = 1;
1567 			break;
1568 		case 'n':
1569 			ctx.dev_id = strtol(optarg, NULL, 10);
1570 			break;
1571 		case 't':
1572 			if (strlen(optarg) < sizeof(ctx.tgt_type))
1573 				strcpy(ctx.tgt_type, optarg);
1574 			break;
1575 		case 'q':
1576 			ctx.nr_hw_queues = strtol(optarg, NULL, 10);
1577 			break;
1578 		case 'd':
1579 			ctx.queue_depth = strtol(optarg, NULL, 10);
1580 			break;
1581 		case 'z':
1582 			ctx.flags |= UBLK_F_SUPPORT_ZERO_COPY | UBLK_F_USER_COPY;
1583 			break;
1584 		case 'r':
1585 			value = strtol(optarg, NULL, 10);
1586 			if (value)
1587 				ctx.flags |= UBLK_F_USER_RECOVERY;
1588 			break;
1589 		case 'e':
1590 			value = strtol(optarg, NULL, 10);
1591 			if (value)
1592 				ctx.flags |= UBLK_F_USER_RECOVERY | UBLK_F_USER_RECOVERY_FAIL_IO;
1593 			break;
1594 		case 'i':
1595 			value = strtol(optarg, NULL, 10);
1596 			if (value)
1597 				ctx.flags |= UBLK_F_USER_RECOVERY | UBLK_F_USER_RECOVERY_REISSUE;
1598 			break;
1599 		case 'g':
1600 			ctx.flags |= UBLK_F_NEED_GET_DATA;
1601 			break;
1602 		case 's':
1603 			ctx.size = strtoull(optarg, NULL, 10);
1604 			break;
1605 		case 0:
1606 			if (!strcmp(longopts[option_idx].name, "debug_mask"))
1607 				ublk_dbg_mask = strtol(optarg, NULL, 16);
1608 			if (!strcmp(longopts[option_idx].name, "quiet"))
1609 				ublk_dbg_mask = 0;
1610 			if (!strcmp(longopts[option_idx].name, "foreground"))
1611 				ctx.fg = 1;
1612 			if (!strcmp(longopts[option_idx].name, "auto_zc"))
1613 				ctx.flags |= UBLK_F_AUTO_BUF_REG;
1614 			if (!strcmp(longopts[option_idx].name, "auto_zc_fallback"))
1615 				ctx.auto_zc_fallback = 1;
1616 			if (!strcmp(longopts[option_idx].name, "nthreads"))
1617 				ctx.nthreads = strtol(optarg, NULL, 10);
1618 			if (!strcmp(longopts[option_idx].name, "per_io_tasks"))
1619 				ctx.per_io_tasks = 1;
1620 			break;
1621 		case '?':
1622 			/*
1623 			 * target requires every option must have argument
1624 			 */
1625 			if (argv[optind][0] == '-' || argv[optind - 1][0] != '-') {
1626 				fprintf(stderr, "every target option requires argument: %s %s\n",
1627 						argv[optind - 1], argv[optind]);
1628 				exit(EXIT_FAILURE);
1629 			}
1630 
1631 			if (tgt_argc < (MAX_NR_TGT_ARG - 1) / 2) {
1632 				tgt_argv[tgt_argc++] = argv[optind - 1];
1633 				tgt_argv[tgt_argc++] = argv[optind];
1634 			} else {
1635 				fprintf(stderr, "too many target options\n");
1636 				exit(EXIT_FAILURE);
1637 			}
1638 			optind += 1;
1639 			break;
1640 		}
1641 	}
1642 
1643 	/* auto_zc_fallback depends on F_AUTO_BUF_REG & F_SUPPORT_ZERO_COPY */
1644 	if (ctx.auto_zc_fallback &&
1645 	    !((ctx.flags & UBLK_F_AUTO_BUF_REG) &&
1646 		    (ctx.flags & UBLK_F_SUPPORT_ZERO_COPY))) {
1647 		ublk_err("%s: auto_zc_fallback is set but neither "
1648 				"F_AUTO_BUF_REG nor F_SUPPORT_ZERO_COPY is enabled\n",
1649 					__func__);
1650 		return -EINVAL;
1651 	}
1652 
1653 	i = optind;
1654 	while (i < argc && ctx.nr_files < MAX_BACK_FILES) {
1655 		ctx.files[ctx.nr_files++] = argv[i++];
1656 	}
1657 
1658 	ops = ublk_find_tgt(ctx.tgt_type);
1659 	if (ops && ops->parse_cmd_line) {
1660 		optind = 0;
1661 
1662 		tgt_argv[0] = ctx.tgt_type;
1663 		ops->parse_cmd_line(&ctx, tgt_argc, tgt_argv);
1664 	}
1665 
1666 	if (!strcmp(cmd, "add"))
1667 		ret = cmd_dev_add(&ctx);
1668 	else if (!strcmp(cmd, "recover")) {
1669 		if (ctx.dev_id < 0) {
1670 			fprintf(stderr, "device id isn't provided for recovering\n");
1671 			ret = -EINVAL;
1672 		} else {
1673 			ctx.recovery = 1;
1674 			ret = cmd_dev_add(&ctx);
1675 		}
1676 	} else if (!strcmp(cmd, "del"))
1677 		ret = cmd_dev_del(&ctx);
1678 	else if (!strcmp(cmd, "list")) {
1679 		ctx.all = 1;
1680 		ret = cmd_dev_list(&ctx);
1681 	} else if (!strcmp(cmd, "help"))
1682 		ret = cmd_dev_help(argv[0]);
1683 	else if (!strcmp(cmd, "features"))
1684 		ret = cmd_dev_get_features();
1685 	else if (!strcmp(cmd, "update_size"))
1686 		ret = cmd_dev_update_size(&ctx);
1687 	else if (!strcmp(cmd, "quiesce"))
1688 		ret = cmd_dev_quiesce(&ctx);
1689 	else
1690 		cmd_dev_help(argv[0]);
1691 
1692 	return ret;
1693 }
1694