xref: /spdk/lib/vhost/vhost_internal.h (revision 26cac6bf15cd3e90bf6221c5c53672ec2befca30)
1 /*   SPDX-License-Identifier: BSD-3-Clause
2  *   Copyright (C) 2017 Intel Corporation.
3  *   All rights reserved.
4  */
5 
6 #ifndef SPDK_VHOST_INTERNAL_H
7 #define SPDK_VHOST_INTERNAL_H
8 #include <linux/virtio_config.h>
9 
10 #include "spdk/stdinc.h"
11 
12 #include <rte_vhost.h>
13 
14 #include "spdk_internal/vhost_user.h"
15 #include "spdk/bdev.h"
16 #include "spdk/log.h"
17 #include "spdk/util.h"
18 #include "spdk/rpc.h"
19 #include "spdk/config.h"
20 
21 #define SPDK_VHOST_MAX_VQUEUES	256
22 #define SPDK_VHOST_MAX_VQ_SIZE	1024
23 
24 #define SPDK_VHOST_SCSI_CTRLR_MAX_DEVS 8
25 
26 #define SPDK_VHOST_IOVS_MAX 129
27 
28 #define SPDK_VHOST_VQ_MAX_SUBMISSIONS	32
29 
30 /*
31  * Rate at which stats are checked for interrupt coalescing.
32  */
33 #define SPDK_VHOST_STATS_CHECK_INTERVAL_MS 10
34 /*
35  * Default threshold at which interrupts start to be coalesced.
36  */
37 #define SPDK_VHOST_VQ_IOPS_COALESCING_THRESHOLD 60000
38 
39 /*
40  * Currently coalescing is not used by default.
41  * Setting this to value > 0 here or by RPC will enable coalescing.
42  */
43 #define SPDK_VHOST_COALESCING_DELAY_BASE_US 0
44 
45 #define SPDK_VHOST_FEATURES ((1ULL << VHOST_F_LOG_ALL) | \
46 	(1ULL << VHOST_USER_F_PROTOCOL_FEATURES) | \
47 	(1ULL << VIRTIO_F_VERSION_1) | \
48 	(1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) | \
49 	(1ULL << VIRTIO_RING_F_EVENT_IDX) | \
50 	(1ULL << VIRTIO_RING_F_INDIRECT_DESC) | \
51 	(1ULL << VIRTIO_F_ANY_LAYOUT))
52 
53 #define SPDK_VHOST_DISABLED_FEATURES ((1ULL << VIRTIO_RING_F_EVENT_IDX) | \
54 	(1ULL << VIRTIO_F_NOTIFY_ON_EMPTY))
55 
56 #define VRING_DESC_F_AVAIL	(1ULL << VRING_PACKED_DESC_F_AVAIL)
57 #define VRING_DESC_F_USED	(1ULL << VRING_PACKED_DESC_F_USED)
58 #define VRING_DESC_F_AVAIL_USED	(VRING_DESC_F_AVAIL | VRING_DESC_F_USED)
59 
60 typedef struct rte_vhost_resubmit_desc spdk_vhost_resubmit_desc;
61 typedef struct rte_vhost_resubmit_info spdk_vhost_resubmit_info;
62 typedef struct rte_vhost_inflight_desc_packed	spdk_vhost_inflight_desc;
63 
64 struct spdk_vhost_virtqueue {
65 	struct rte_vhost_vring vring;
66 	struct rte_vhost_ring_inflight vring_inflight;
67 	uint16_t last_avail_idx;
68 	uint16_t last_used_idx;
69 
70 	struct {
71 		/* To mark a descriptor as available in packed ring
72 		 * Equal to avail_wrap_counter in spec.
73 		 */
74 		uint8_t avail_phase	: 1;
75 		/* To mark a descriptor as used in packed ring
76 		 * Equal to used_wrap_counter in spec.
77 		 */
78 		uint8_t used_phase	: 1;
79 		uint8_t padding		: 5;
80 		bool packed_ring	: 1;
81 	} packed;
82 
83 	void *tasks;
84 
85 	/* Request count from last stats check */
86 	uint32_t req_cnt;
87 
88 	/* Request count from last event */
89 	uint16_t used_req_cnt;
90 
91 	/* How long interrupt is delayed */
92 	uint32_t irq_delay_time;
93 
94 	/* Next time when we need to send event */
95 	uint64_t next_event_time;
96 
97 	/* Associated vhost_virtqueue in the virtio device's virtqueue list */
98 	uint32_t vring_idx;
99 
100 	struct spdk_vhost_session *vsession;
101 
102 	struct spdk_interrupt *intr;
103 } __attribute((aligned(SPDK_CACHE_LINE_SIZE)));
104 
105 struct spdk_vhost_session {
106 	struct spdk_vhost_dev *vdev;
107 
108 	/* rte_vhost connection ID. */
109 	int vid;
110 
111 	/* Unique session ID. */
112 	uint64_t id;
113 	/* Unique session name. */
114 	char *name;
115 
116 	bool started;
117 	bool interrupt_mode;
118 
119 	struct rte_vhost_memory *mem;
120 
121 	int task_cnt;
122 
123 	uint16_t max_queues;
124 
125 	uint64_t negotiated_features;
126 
127 	/* Local copy of device coalescing settings. */
128 	uint32_t coalescing_delay_time_base;
129 	uint32_t coalescing_io_rate_threshold;
130 
131 	/* Next time when stats for event coalescing will be checked. */
132 	uint64_t next_stats_check_time;
133 
134 	/* Interval used for event coalescing checking. */
135 	uint64_t stats_check_interval;
136 
137 	/* Session's stop poller will only try limited times to destroy the session. */
138 	uint32_t stop_retry_count;
139 
140 	struct spdk_vhost_virtqueue virtqueue[SPDK_VHOST_MAX_VQUEUES];
141 
142 	TAILQ_ENTRY(spdk_vhost_session) tailq;
143 };
144 
145 struct spdk_vhost_user_dev {
146 	struct spdk_vhost_dev *vdev;
147 
148 	const struct spdk_vhost_user_dev_backend *user_backend;
149 
150 	/* Saved original values used to setup coalescing to avoid integer
151 	 * rounding issues during save/load config.
152 	 */
153 	uint32_t coalescing_delay_us;
154 	uint32_t coalescing_iops_threshold;
155 
156 	bool registered;
157 
158 	/* Use this lock to protect multiple sessions. */
159 	pthread_mutex_t lock;
160 
161 	/* Current connections to the device */
162 	TAILQ_HEAD(, spdk_vhost_session) vsessions;
163 
164 	/* Increment-only session counter */
165 	uint64_t vsessions_num;
166 
167 	/* Number of pending asynchronous operations */
168 	uint32_t pending_async_op_num;
169 };
170 
171 struct spdk_vhost_dev {
172 	char *name;
173 	char *path;
174 
175 	struct spdk_thread *thread;
176 
177 	uint64_t virtio_features;
178 	uint64_t disabled_features;
179 	uint64_t protocol_features;
180 
181 	const struct spdk_vhost_dev_backend *backend;
182 
183 	/* Context passed from transport */
184 	void *ctxt;
185 
186 	TAILQ_ENTRY(spdk_vhost_dev) tailq;
187 };
188 
189 static inline struct spdk_vhost_user_dev *
190 to_user_dev(struct spdk_vhost_dev *vdev)
191 {
192 	assert(vdev != NULL);
193 	return vdev->ctxt;
194 }
195 
196 /**
197  * \param vdev vhost device.
198  * \param vsession vhost session.
199  * \param arg user-provided parameter.
200  *
201  * \return negative values will break the foreach call, meaning
202  * the function won't be called again. Return codes zero and
203  * positive don't have any effect.
204  */
205 typedef int (*spdk_vhost_session_fn)(struct spdk_vhost_dev *vdev,
206 				     struct spdk_vhost_session *vsession,
207 				     void *arg);
208 
209 /**
210  * \param vdev vhost device.
211  * \param arg user-provided parameter.
212  */
213 typedef void (*spdk_vhost_dev_fn)(struct spdk_vhost_dev *vdev, void *arg);
214 
215 struct spdk_vhost_user_dev_backend {
216 	/**
217 	 * Size of additional per-session context data
218 	 * allocated whenever a new client connects.
219 	 */
220 	size_t session_ctx_size;
221 
222 	spdk_vhost_session_fn start_session;
223 	spdk_vhost_session_fn stop_session;
224 	int (*alloc_vq_tasks)(struct spdk_vhost_session *vsession, uint16_t qid);
225 	void (*register_vq_interrupt)(struct spdk_vhost_session *vsession, struct spdk_vhost_virtqueue *vq);
226 };
227 
228 enum vhost_backend_type {
229 	VHOST_BACKEND_BLK = 0,
230 	VHOST_BACKEND_SCSI,
231 };
232 
233 struct spdk_vhost_dev_backend {
234 	enum vhost_backend_type type;
235 
236 	int (*vhost_get_config)(struct spdk_vhost_dev *vdev, uint8_t *config, uint32_t len);
237 	int (*vhost_set_config)(struct spdk_vhost_dev *vdev, uint8_t *config,
238 				uint32_t offset, uint32_t size, uint32_t flags);
239 
240 	void (*dump_info_json)(struct spdk_vhost_dev *vdev, struct spdk_json_write_ctx *w);
241 	void (*write_config_json)(struct spdk_vhost_dev *vdev, struct spdk_json_write_ctx *w);
242 	int (*remove_device)(struct spdk_vhost_dev *vdev);
243 	int (*set_coalescing)(struct spdk_vhost_dev *vdev, uint32_t delay_base_us,
244 			      uint32_t iops_threshold);
245 	void (*get_coalescing)(struct spdk_vhost_dev *vdev, uint32_t *delay_base_us,
246 			       uint32_t *iops_threshold);
247 };
248 
249 void *vhost_gpa_to_vva(struct spdk_vhost_session *vsession, uint64_t addr, uint64_t len);
250 
251 uint16_t vhost_vq_avail_ring_get(struct spdk_vhost_virtqueue *vq, uint16_t *reqs,
252 				 uint16_t reqs_len);
253 
254 /**
255  * Get a virtio split descriptor at given index in given virtqueue.
256  * The descriptor will provide access to the entire descriptor
257  * chain. The subsequent descriptors are accessible via
258  * \c spdk_vhost_vring_desc_get_next.
259  * \param vsession vhost session
260  * \param vq virtqueue
261  * \param req_idx descriptor index
262  * \param desc pointer to be set to the descriptor
263  * \param desc_table descriptor table to be used with
264  * \c spdk_vhost_vring_desc_get_next. This might be either
265  * default virtqueue descriptor table or per-chain indirect
266  * table.
267  * \param desc_table_size size of the *desc_table*
268  * \return 0 on success, -1 if given index is invalid.
269  * If -1 is returned, the content of params is undefined.
270  */
271 int vhost_vq_get_desc(struct spdk_vhost_session *vsession, struct spdk_vhost_virtqueue *vq,
272 		      uint16_t req_idx, struct vring_desc **desc, struct vring_desc **desc_table,
273 		      uint32_t *desc_table_size);
274 
275 /**
276  * Get a virtio packed descriptor at given index in given virtqueue.
277  * The descriptor will provide access to the entire descriptor
278  * chain. The subsequent descriptors are accessible via
279  * \c vhost_vring_packed_desc_get_next.
280  * \param vsession vhost session
281  * \param vq virtqueue
282  * \param req_idx descriptor index
283  * \param desc pointer to be set to the descriptor
284  * \param desc_table descriptor table to be used with
285  * \c spdk_vhost_vring_desc_get_next. This might be either
286  * \c NULL or per-chain indirect table.
287  * \param desc_table_size size of the *desc_table*
288  * \return 0 on success, -1 if given index is invalid.
289  * If -1 is returned, the content of params is undefined.
290  */
291 int vhost_vq_get_desc_packed(struct spdk_vhost_session *vsession,
292 			     struct spdk_vhost_virtqueue *virtqueue,
293 			     uint16_t req_idx, struct vring_packed_desc **desc,
294 			     struct vring_packed_desc **desc_table, uint32_t *desc_table_size);
295 
296 int vhost_inflight_queue_get_desc(struct spdk_vhost_session *vsession,
297 				  spdk_vhost_inflight_desc *desc_array,
298 				  uint16_t req_idx, spdk_vhost_inflight_desc **desc,
299 				  struct vring_packed_desc  **desc_table, uint32_t *desc_table_size);
300 
301 /**
302  * Send IRQ/call client (if pending) for \c vq.
303  * \param vsession vhost session
304  * \param vq virtqueue
305  * \return
306  *   0 - if no interrupt was signalled
307  *   1 - if interrupt was signalled
308  */
309 int vhost_vq_used_signal(struct spdk_vhost_session *vsession, struct spdk_vhost_virtqueue *vq);
310 
311 /**
312  * Send IRQs for the queue that need to be signaled.
313  * \param vq virtqueue
314  */
315 void vhost_session_vq_used_signal(struct spdk_vhost_virtqueue *virtqueue);
316 
317 void vhost_vq_used_ring_enqueue(struct spdk_vhost_session *vsession,
318 				struct spdk_vhost_virtqueue *vq,
319 				uint16_t id, uint32_t len);
320 
321 /**
322  * Enqueue the entry to the used ring when device complete the request.
323  * \param vsession vhost session
324  * \param vq virtqueue
325  * \req_idx descriptor index. It's the first index of this descriptor chain.
326  * \num_descs descriptor count. It's the count of the number of buffers in the chain.
327  * \buffer_id descriptor buffer ID.
328  * \length device write length. Specify the length of the buffer that has been initialized
329  * (written to) by the device
330  * \inflight_head the head idx of this IO inflight desc chain.
331  */
332 void vhost_vq_packed_ring_enqueue(struct spdk_vhost_session *vsession,
333 				  struct spdk_vhost_virtqueue *virtqueue,
334 				  uint16_t num_descs, uint16_t buffer_id,
335 				  uint32_t length, uint16_t inflight_head);
336 
337 /**
338  * Get subsequent descriptor from given table.
339  * \param desc current descriptor, will be set to the
340  * next descriptor (NULL in case this is the last
341  * descriptor in the chain or the next desc is invalid)
342  * \param desc_table descriptor table
343  * \param desc_table_size size of the *desc_table*
344  * \return 0 on success, -1 if given index is invalid
345  * The *desc* param will be set regardless of the
346  * return value.
347  */
348 int vhost_vring_desc_get_next(struct vring_desc **desc,
349 			      struct vring_desc *desc_table, uint32_t desc_table_size);
350 static inline bool
351 vhost_vring_desc_is_wr(struct vring_desc *cur_desc)
352 {
353 	return !!(cur_desc->flags & VRING_DESC_F_WRITE);
354 }
355 
356 int vhost_vring_desc_to_iov(struct spdk_vhost_session *vsession, struct iovec *iov,
357 			    uint16_t *iov_index, const struct vring_desc *desc);
358 
359 bool vhost_vq_packed_ring_is_avail(struct spdk_vhost_virtqueue *virtqueue);
360 
361 /**
362  * Get subsequent descriptor from vq or desc table.
363  * \param desc current descriptor, will be set to the
364  * next descriptor (NULL in case this is the last
365  * descriptor in the chain or the next desc is invalid)
366  * \req_idx index of current desc, will be set to the next
367  * index. If desc_table != NULL the req_idx is the the vring index
368  * or the req_idx is the desc_table index.
369  * \param desc_table descriptor table
370  * \param desc_table_size size of the *desc_table*
371  * \return 0 on success, -1 if given index is invalid
372  * The *desc* param will be set regardless of the
373  * return value.
374  */
375 int vhost_vring_packed_desc_get_next(struct vring_packed_desc **desc, uint16_t *req_idx,
376 				     struct spdk_vhost_virtqueue *vq,
377 				     struct vring_packed_desc *desc_table,
378 				     uint32_t desc_table_size);
379 
380 bool vhost_vring_packed_desc_is_wr(struct vring_packed_desc *cur_desc);
381 
382 int vhost_vring_packed_desc_to_iov(struct spdk_vhost_session *vsession, struct iovec *iov,
383 				   uint16_t *iov_index, const struct vring_packed_desc *desc);
384 
385 bool vhost_vring_inflight_desc_is_wr(spdk_vhost_inflight_desc *cur_desc);
386 
387 int vhost_vring_inflight_desc_to_iov(struct spdk_vhost_session *vsession, struct iovec *iov,
388 				     uint16_t *iov_index, const spdk_vhost_inflight_desc *desc);
389 
390 uint16_t vhost_vring_packed_desc_get_buffer_id(struct spdk_vhost_virtqueue *vq, uint16_t req_idx,
391 		uint16_t *num_descs);
392 
393 static inline bool
394 __attribute__((always_inline))
395 vhost_dev_has_feature(struct spdk_vhost_session *vsession, unsigned feature_id)
396 {
397 	return vsession->negotiated_features & (1ULL << feature_id);
398 }
399 
400 int vhost_dev_register(struct spdk_vhost_dev *vdev, const char *name, const char *mask_str,
401 		       const struct spdk_json_val *params,
402 		       const struct spdk_vhost_dev_backend *backend,
403 		       const struct spdk_vhost_user_dev_backend *user_backend);
404 int vhost_dev_unregister(struct spdk_vhost_dev *vdev);
405 
406 void vhost_dump_info_json(struct spdk_vhost_dev *vdev, struct spdk_json_write_ctx *w);
407 
408 /*
409  * Set vhost session to run in interrupt or poll mode
410  */
411 void vhost_user_session_set_interrupt_mode(struct spdk_vhost_session *vsession,
412 		bool interrupt_mode);
413 
414 /*
415  * Memory registration functions used in start/stop device callbacks
416  */
417 void vhost_session_mem_register(struct rte_vhost_memory *mem);
418 void vhost_session_mem_unregister(struct rte_vhost_memory *mem);
419 
420 /*
421  * Call a function for each session of the provided vhost device.
422  * The function will be called one-by-one on each session's thread.
423  *
424  * \param vdev vhost device
425  * \param fn function to call on each session's thread
426  * \param cpl_fn function to be called at the end of the iteration on
427  * the vhost management thread.
428  * Optional, can be NULL.
429  * \param arg additional argument to the both callbacks
430  */
431 void vhost_user_dev_foreach_session(struct spdk_vhost_dev *dev,
432 				    spdk_vhost_session_fn fn,
433 				    spdk_vhost_dev_fn cpl_fn,
434 				    void *arg);
435 
436 /**
437  * Finish a blocking vhost_user_wait_for_session_stop() call and finally
438  * stop the session. This must be called on the session's lcore which
439  * used to receive all session-related messages (e.g. from
440  * vhost_user_dev_foreach_session()). After this call, the session-
441  * related messages will be once again processed by any arbitrary thread.
442  *
443  * Must be called under the vhost user device's session access lock.
444  *
445  * \param vsession vhost session
446  * \param response return code
447  */
448 void vhost_user_session_stop_done(struct spdk_vhost_session *vsession, int response);
449 
450 struct spdk_vhost_session *vhost_session_find_by_vid(int vid);
451 void vhost_session_install_rte_compat_hooks(struct spdk_vhost_session *vsession);
452 int vhost_register_unix_socket(const char *path, const char *ctrl_name,
453 			       uint64_t virtio_features, uint64_t disabled_features, uint64_t protocol_features);
454 int vhost_driver_unregister(const char *path);
455 int vhost_get_mem_table(int vid, struct rte_vhost_memory **mem);
456 int vhost_get_negotiated_features(int vid, uint64_t *negotiated_features);
457 
458 int remove_vhost_controller(struct spdk_vhost_dev *vdev);
459 
460 struct spdk_io_channel *vhost_blk_get_io_channel(struct spdk_vhost_dev *vdev);
461 void vhost_blk_put_io_channel(struct spdk_io_channel *ch);
462 
463 /* The spdk_bdev pointer should only be used to retrieve
464  * the device properties, ex. number of blocks or I/O type supported. */
465 struct spdk_bdev *vhost_blk_get_bdev(struct spdk_vhost_dev *vdev);
466 
467 /* Function calls from vhost.c to rte_vhost_user.c,
468  * shall removed once virtio transport abstraction is complete. */
469 int vhost_user_session_set_coalescing(struct spdk_vhost_dev *dev,
470 				      struct spdk_vhost_session *vsession, void *ctx);
471 int vhost_user_dev_set_coalescing(struct spdk_vhost_user_dev *user_dev, uint32_t delay_base_us,
472 				  uint32_t iops_threshold);
473 int vhost_user_dev_register(struct spdk_vhost_dev *vdev, const char *name,
474 			    struct spdk_cpuset *cpumask, const struct spdk_vhost_user_dev_backend *user_backend);
475 int vhost_user_dev_unregister(struct spdk_vhost_dev *vdev);
476 int vhost_user_init(void);
477 void vhost_user_fini(spdk_vhost_fini_cb vhost_cb);
478 int vhost_user_set_coalescing(struct spdk_vhost_dev *vdev, uint32_t delay_base_us,
479 			      uint32_t iops_threshold);
480 void vhost_user_get_coalescing(struct spdk_vhost_dev *vdev, uint32_t *delay_base_us,
481 			       uint32_t *iops_threshold);
482 
483 int virtio_blk_construct_ctrlr(struct spdk_vhost_dev *vdev, const char *address,
484 			       struct spdk_cpuset *cpumask, const struct spdk_json_val *params,
485 			       const struct spdk_vhost_user_dev_backend *user_backend);
486 int virtio_blk_destroy_ctrlr(struct spdk_vhost_dev *vdev);
487 
488 struct spdk_vhost_blk_task;
489 
490 typedef void (*virtio_blk_request_cb)(uint8_t status, struct spdk_vhost_blk_task *task,
491 				      void *cb_arg);
492 
493 struct spdk_vhost_blk_task {
494 	struct spdk_bdev_io *bdev_io;
495 	virtio_blk_request_cb cb;
496 	void *cb_arg;
497 
498 	volatile uint8_t *status;
499 
500 	/* for io wait */
501 	struct spdk_bdev_io_wait_entry bdev_io_wait;
502 	struct spdk_io_channel *bdev_io_wait_ch;
503 	struct spdk_vhost_dev *bdev_io_wait_vdev;
504 
505 	/** Number of bytes that were written. */
506 	uint32_t used_len;
507 	uint16_t iovcnt;
508 	struct iovec iovs[SPDK_VHOST_IOVS_MAX];
509 
510 	/** Size of whole payload in bytes */
511 	uint32_t payload_size;
512 };
513 
514 int virtio_blk_process_request(struct spdk_vhost_dev *vdev, struct spdk_io_channel *ch,
515 			       struct spdk_vhost_blk_task *task, virtio_blk_request_cb cb, void *cb_arg);
516 
517 typedef void (*bdev_event_cb_complete)(struct spdk_vhost_dev *vdev, void *ctx);
518 
519 #define SPDK_VIRTIO_BLK_TRSTRING_MAX_LEN 32
520 
521 struct spdk_virtio_blk_transport_ops {
522 	/**
523 	 * Transport name
524 	 */
525 	char name[SPDK_VIRTIO_BLK_TRSTRING_MAX_LEN];
526 
527 	/**
528 	 * Create a transport for the given transport opts
529 	 */
530 	struct spdk_virtio_blk_transport *(*create)(const struct spdk_json_val *params);
531 
532 	/**
533 	 * Dump transport-specific opts into JSON
534 	 */
535 	void (*dump_opts)(struct spdk_virtio_blk_transport *transport, struct spdk_json_write_ctx *w);
536 
537 	/**
538 	 * Destroy the transport
539 	 */
540 	int (*destroy)(struct spdk_virtio_blk_transport *transport,
541 		       spdk_vhost_fini_cb cb_fn);
542 
543 	/**
544 	 * Create vhost block controller
545 	 */
546 	int (*create_ctrlr)(struct spdk_vhost_dev *vdev, struct spdk_cpuset *cpumask,
547 			    const char *address, const struct spdk_json_val *params,
548 			    void *custom_opts);
549 
550 	/**
551 	 * Destroy vhost block controller
552 	 */
553 	int (*destroy_ctrlr)(struct spdk_vhost_dev *vdev);
554 
555 	/*
556 	 * Signal removal of the bdev.
557 	 */
558 	void (*bdev_event)(enum spdk_bdev_event_type type, struct spdk_vhost_dev *vdev,
559 			   bdev_event_cb_complete cb, void *cb_arg);
560 
561 	/**
562 	 * Set coalescing parameters.
563 	 */
564 	int (*set_coalescing)(struct spdk_vhost_dev *vdev, uint32_t delay_base_us,
565 			      uint32_t iops_threshold);
566 
567 	/**
568 	 * Get coalescing parameters.
569 	 */
570 	void (*get_coalescing)(struct spdk_vhost_dev *vdev, uint32_t *delay_base_us,
571 			       uint32_t *iops_threshold);
572 };
573 
574 struct spdk_virtio_blk_transport {
575 	const struct spdk_virtio_blk_transport_ops	*ops;
576 	TAILQ_ENTRY(spdk_virtio_blk_transport)		tailq;
577 };
578 
579 struct virtio_blk_transport_ops_list_element {
580 	struct spdk_virtio_blk_transport_ops			ops;
581 	TAILQ_ENTRY(virtio_blk_transport_ops_list_element)	link;
582 };
583 
584 void virtio_blk_transport_register(const struct spdk_virtio_blk_transport_ops *ops);
585 int virtio_blk_transport_create(const char *transport_name, const struct spdk_json_val *params);
586 int virtio_blk_transport_destroy(struct spdk_virtio_blk_transport *transport,
587 				 spdk_vhost_fini_cb cb_fn);
588 struct spdk_virtio_blk_transport *virtio_blk_transport_get_first(void);
589 struct spdk_virtio_blk_transport *virtio_blk_transport_get_next(
590 	struct spdk_virtio_blk_transport *transport);
591 void virtio_blk_transport_dump_opts(struct spdk_virtio_blk_transport *transport,
592 				    struct spdk_json_write_ctx *w);
593 struct spdk_virtio_blk_transport *virtio_blk_tgt_get_transport(const char *transport_name);
594 const struct spdk_virtio_blk_transport_ops *virtio_blk_get_transport_ops(
595 	const char *transport_name);
596 
597 void vhost_session_info_json(struct spdk_vhost_dev *vdev, struct spdk_json_write_ctx *w);
598 
599 /*
600  * Macro used to register new transports.
601  */
602 #define SPDK_VIRTIO_BLK_TRANSPORT_REGISTER(name, transport_ops) \
603 static void __attribute__((constructor)) _virtio_blk_transport_register_##name(void) \
604 { \
605 	virtio_blk_transport_register(transport_ops); \
606 }
607 
608 #endif /* SPDK_VHOST_INTERNAL_H */
609