xref: /spdk/lib/vhost/vhost_internal.h (revision a6dbe3721eb3b5990707fc3e378c95e505dd8ab5)
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_RING_PACKED) | \
52 	(1ULL << VIRTIO_F_ANY_LAYOUT))
53 
54 #define SPDK_VHOST_DISABLED_FEATURES ((1ULL << VIRTIO_RING_F_EVENT_IDX) | \
55 	(1ULL << VIRTIO_F_NOTIFY_ON_EMPTY))
56 
57 #define VRING_DESC_F_AVAIL	(1ULL << VRING_PACKED_DESC_F_AVAIL)
58 #define VRING_DESC_F_USED	(1ULL << VRING_PACKED_DESC_F_USED)
59 #define VRING_DESC_F_AVAIL_USED	(VRING_DESC_F_AVAIL | VRING_DESC_F_USED)
60 
61 typedef struct rte_vhost_resubmit_desc spdk_vhost_resubmit_desc;
62 typedef struct rte_vhost_resubmit_info spdk_vhost_resubmit_info;
63 typedef struct rte_vhost_inflight_desc_packed	spdk_vhost_inflight_desc;
64 
65 struct spdk_vhost_virtqueue {
66 	struct rte_vhost_vring vring;
67 	struct rte_vhost_ring_inflight vring_inflight;
68 	uint16_t last_avail_idx;
69 	uint16_t last_used_idx;
70 
71 	struct {
72 		/* To mark a descriptor as available in packed ring
73 		 * Equal to avail_wrap_counter in spec.
74 		 */
75 		uint8_t avail_phase	: 1;
76 		/* To mark a descriptor as used in packed ring
77 		 * Equal to used_wrap_counter in spec.
78 		 */
79 		uint8_t used_phase	: 1;
80 		uint8_t padding		: 5;
81 		bool packed_ring	: 1;
82 	} packed;
83 
84 	void *tasks;
85 
86 	/* Request count from last stats check */
87 	uint32_t req_cnt;
88 
89 	/* Request count from last event */
90 	uint16_t used_req_cnt;
91 
92 	/* How long interrupt is delayed */
93 	uint32_t irq_delay_time;
94 
95 	/* Next time when we need to send event */
96 	uint64_t next_event_time;
97 
98 	/* Associated vhost_virtqueue in the virtio device's virtqueue list */
99 	uint32_t vring_idx;
100 
101 	struct spdk_vhost_session *vsession;
102 
103 	struct spdk_interrupt *intr;
104 } __attribute((aligned(SPDK_CACHE_LINE_SIZE)));
105 
106 struct spdk_vhost_session {
107 	struct spdk_vhost_dev *vdev;
108 
109 	/* rte_vhost connection ID. */
110 	int vid;
111 
112 	/* Unique session ID. */
113 	uint64_t id;
114 	/* Unique session name. */
115 	char *name;
116 
117 	bool started;
118 	bool interrupt_mode;
119 
120 	struct rte_vhost_memory *mem;
121 
122 	int task_cnt;
123 
124 	uint16_t max_queues;
125 
126 	uint64_t negotiated_features;
127 
128 	/* Local copy of device coalescing settings. */
129 	uint32_t coalescing_delay_time_base;
130 	uint32_t coalescing_io_rate_threshold;
131 
132 	/* Next time when stats for event coalescing will be checked. */
133 	uint64_t next_stats_check_time;
134 
135 	/* Interval used for event coalescing checking. */
136 	uint64_t stats_check_interval;
137 
138 	/* Session's stop poller will only try limited times to destroy the session. */
139 	uint32_t stop_retry_count;
140 
141 	struct spdk_vhost_virtqueue virtqueue[SPDK_VHOST_MAX_VQUEUES];
142 
143 	TAILQ_ENTRY(spdk_vhost_session) tailq;
144 };
145 
146 struct spdk_vhost_user_dev {
147 	struct spdk_vhost_dev *vdev;
148 
149 	const struct spdk_vhost_user_dev_backend *user_backend;
150 
151 	/* Saved original values used to setup coalescing to avoid integer
152 	 * rounding issues during save/load config.
153 	 */
154 	uint32_t coalescing_delay_us;
155 	uint32_t coalescing_iops_threshold;
156 
157 	/* Current connections to the device */
158 	TAILQ_HEAD(, spdk_vhost_session) vsessions;
159 
160 	/* Increment-only session counter */
161 	uint64_t vsessions_num;
162 
163 	/* Number of started and actively polled sessions */
164 	uint32_t active_session_num;
165 
166 	/* Number of pending asynchronous operations */
167 	uint32_t pending_async_op_num;
168 };
169 
170 struct spdk_vhost_dev {
171 	char *name;
172 	char *path;
173 
174 	struct spdk_thread *thread;
175 	bool registered;
176 
177 	uint64_t virtio_features;
178 	uint64_t disabled_features;
179 	uint64_t protocol_features;
180 	bool packed_ring_recovery;
181 
182 	const struct spdk_vhost_dev_backend *backend;
183 
184 	/* Context passed from transport */
185 	void *ctxt;
186 
187 	TAILQ_ENTRY(spdk_vhost_dev) tailq;
188 };
189 
190 /**
191  * \param vdev vhost device.
192  * \param vsession vhost session.
193  * \param arg user-provided parameter.
194  *
195  * \return negative values will break the foreach call, meaning
196  * the function won't be called again. Return codes zero and
197  * positive don't have any effect.
198  */
199 typedef int (*spdk_vhost_session_fn)(struct spdk_vhost_dev *vdev,
200 				     struct spdk_vhost_session *vsession,
201 				     void *arg);
202 
203 /**
204  * \param vdev vhost device.
205  * \param arg user-provided parameter.
206  */
207 typedef void (*spdk_vhost_dev_fn)(struct spdk_vhost_dev *vdev, void *arg);
208 
209 struct spdk_vhost_user_dev_backend {
210 	/**
211 	 * Size of additional per-session context data
212 	 * allocated whenever a new client connects.
213 	 */
214 	size_t session_ctx_size;
215 
216 	spdk_vhost_session_fn start_session;
217 	int (*stop_session)(struct spdk_vhost_session *vsession);
218 	int (*alloc_vq_tasks)(struct spdk_vhost_session *vsession, uint16_t qid);
219 };
220 
221 enum vhost_backend_type {
222 	VHOST_BACKEND_BLK = 0,
223 	VHOST_BACKEND_SCSI,
224 };
225 
226 struct spdk_vhost_dev_backend {
227 	enum vhost_backend_type type;
228 
229 	int (*vhost_get_config)(struct spdk_vhost_dev *vdev, uint8_t *config, uint32_t len);
230 	int (*vhost_set_config)(struct spdk_vhost_dev *vdev, uint8_t *config,
231 				uint32_t offset, uint32_t size, uint32_t flags);
232 
233 	void (*dump_info_json)(struct spdk_vhost_dev *vdev, struct spdk_json_write_ctx *w);
234 	void (*write_config_json)(struct spdk_vhost_dev *vdev, struct spdk_json_write_ctx *w);
235 	int (*remove_device)(struct spdk_vhost_dev *vdev);
236 };
237 
238 void *vhost_gpa_to_vva(struct spdk_vhost_session *vsession, uint64_t addr, uint64_t len);
239 
240 uint16_t vhost_vq_avail_ring_get(struct spdk_vhost_virtqueue *vq, uint16_t *reqs,
241 				 uint16_t reqs_len);
242 
243 /**
244  * Get a virtio split descriptor at given index in given virtqueue.
245  * The descriptor will provide access to the entire descriptor
246  * chain. The subsequent descriptors are accessible via
247  * \c spdk_vhost_vring_desc_get_next.
248  * \param vsession vhost session
249  * \param vq virtqueue
250  * \param req_idx descriptor index
251  * \param desc pointer to be set to the descriptor
252  * \param desc_table descriptor table to be used with
253  * \c spdk_vhost_vring_desc_get_next. This might be either
254  * default virtqueue descriptor table or per-chain indirect
255  * table.
256  * \param desc_table_size size of the *desc_table*
257  * \return 0 on success, -1 if given index is invalid.
258  * If -1 is returned, the content of params is undefined.
259  */
260 int vhost_vq_get_desc(struct spdk_vhost_session *vsession, struct spdk_vhost_virtqueue *vq,
261 		      uint16_t req_idx, struct vring_desc **desc, struct vring_desc **desc_table,
262 		      uint32_t *desc_table_size);
263 
264 /**
265  * Get a virtio packed descriptor at given index in given virtqueue.
266  * The descriptor will provide access to the entire descriptor
267  * chain. The subsequent descriptors are accessible via
268  * \c vhost_vring_packed_desc_get_next.
269  * \param vsession vhost session
270  * \param vq virtqueue
271  * \param req_idx descriptor index
272  * \param desc pointer to be set to the descriptor
273  * \param desc_table descriptor table to be used with
274  * \c spdk_vhost_vring_desc_get_next. This might be either
275  * \c NULL or per-chain indirect table.
276  * \param desc_table_size size of the *desc_table*
277  * \return 0 on success, -1 if given index is invalid.
278  * If -1 is returned, the content of params is undefined.
279  */
280 int vhost_vq_get_desc_packed(struct spdk_vhost_session *vsession,
281 			     struct spdk_vhost_virtqueue *virtqueue,
282 			     uint16_t req_idx, struct vring_packed_desc **desc,
283 			     struct vring_packed_desc **desc_table, uint32_t *desc_table_size);
284 
285 int vhost_inflight_queue_get_desc(struct spdk_vhost_session *vsession,
286 				  spdk_vhost_inflight_desc *desc_array,
287 				  uint16_t req_idx, spdk_vhost_inflight_desc **desc,
288 				  struct vring_packed_desc  **desc_table, uint32_t *desc_table_size);
289 
290 /**
291  * Send IRQ/call client (if pending) for \c vq.
292  * \param vsession vhost session
293  * \param vq virtqueue
294  * \return
295  *   0 - if no interrupt was signalled
296  *   1 - if interrupt was signalled
297  */
298 int vhost_vq_used_signal(struct spdk_vhost_session *vsession, struct spdk_vhost_virtqueue *vq);
299 
300 /**
301  * Send IRQs for the queue that need to be signaled.
302  * \param vq virtqueue
303  */
304 void vhost_session_vq_used_signal(struct spdk_vhost_virtqueue *virtqueue);
305 
306 void vhost_vq_used_ring_enqueue(struct spdk_vhost_session *vsession,
307 				struct spdk_vhost_virtqueue *vq,
308 				uint16_t id, uint32_t len);
309 
310 /**
311  * Enqueue the entry to the used ring when device complete the request.
312  * \param vsession vhost session
313  * \param vq virtqueue
314  * \req_idx descriptor index. It's the first index of this descriptor chain.
315  * \num_descs descriptor count. It's the count of the number of buffers in the chain.
316  * \buffer_id descriptor buffer ID.
317  * \length device write length. Specify the length of the buffer that has been initialized
318  * (written to) by the device
319  * \inflight_head the head idx of this IO inflight desc chain.
320  */
321 void vhost_vq_packed_ring_enqueue(struct spdk_vhost_session *vsession,
322 				  struct spdk_vhost_virtqueue *virtqueue,
323 				  uint16_t num_descs, uint16_t buffer_id,
324 				  uint32_t length, uint16_t inflight_head);
325 
326 /**
327  * Get subsequent descriptor from given table.
328  * \param desc current descriptor, will be set to the
329  * next descriptor (NULL in case this is the last
330  * descriptor in the chain or the next desc is invalid)
331  * \param desc_table descriptor table
332  * \param desc_table_size size of the *desc_table*
333  * \return 0 on success, -1 if given index is invalid
334  * The *desc* param will be set regardless of the
335  * return value.
336  */
337 int vhost_vring_desc_get_next(struct vring_desc **desc,
338 			      struct vring_desc *desc_table, uint32_t desc_table_size);
339 static inline bool
340 vhost_vring_desc_is_wr(struct vring_desc *cur_desc)
341 {
342 	return !!(cur_desc->flags & VRING_DESC_F_WRITE);
343 }
344 
345 int vhost_vring_desc_to_iov(struct spdk_vhost_session *vsession, struct iovec *iov,
346 			    uint16_t *iov_index, const struct vring_desc *desc);
347 
348 bool vhost_vq_packed_ring_is_avail(struct spdk_vhost_virtqueue *virtqueue);
349 
350 /**
351  * Get subsequent descriptor from vq or desc table.
352  * \param desc current descriptor, will be set to the
353  * next descriptor (NULL in case this is the last
354  * descriptor in the chain or the next desc is invalid)
355  * \req_idx index of current desc, will be set to the next
356  * index. If desc_table != NULL the req_idx is the the vring index
357  * or the req_idx is the desc_table index.
358  * \param desc_table descriptor table
359  * \param desc_table_size size of the *desc_table*
360  * \return 0 on success, -1 if given index is invalid
361  * The *desc* param will be set regardless of the
362  * return value.
363  */
364 int vhost_vring_packed_desc_get_next(struct vring_packed_desc **desc, uint16_t *req_idx,
365 				     struct spdk_vhost_virtqueue *vq,
366 				     struct vring_packed_desc *desc_table,
367 				     uint32_t desc_table_size);
368 
369 bool vhost_vring_packed_desc_is_wr(struct vring_packed_desc *cur_desc);
370 
371 int vhost_vring_packed_desc_to_iov(struct spdk_vhost_session *vsession, struct iovec *iov,
372 				   uint16_t *iov_index, const struct vring_packed_desc *desc);
373 
374 bool vhost_vring_inflight_desc_is_wr(spdk_vhost_inflight_desc *cur_desc);
375 
376 int vhost_vring_inflight_desc_to_iov(struct spdk_vhost_session *vsession, struct iovec *iov,
377 				     uint16_t *iov_index, const spdk_vhost_inflight_desc *desc);
378 
379 uint16_t vhost_vring_packed_desc_get_buffer_id(struct spdk_vhost_virtqueue *vq, uint16_t req_idx,
380 		uint16_t *num_descs);
381 
382 static inline bool
383 __attribute__((always_inline))
384 vhost_dev_has_feature(struct spdk_vhost_session *vsession, unsigned feature_id)
385 {
386 	return vsession->negotiated_features & (1ULL << feature_id);
387 }
388 
389 int vhost_dev_register(struct spdk_vhost_dev *vdev, const char *name, const char *mask_str,
390 		       const struct spdk_json_val *params,
391 		       const struct spdk_vhost_dev_backend *backend,
392 		       const struct spdk_vhost_user_dev_backend *user_backend);
393 int vhost_dev_unregister(struct spdk_vhost_dev *vdev);
394 
395 void vhost_dump_info_json(struct spdk_vhost_dev *vdev, struct spdk_json_write_ctx *w);
396 
397 /*
398  * Set vhost session to run in interrupt or poll mode
399  */
400 void vhost_user_session_set_interrupt_mode(struct spdk_vhost_session *vsession,
401 		bool interrupt_mode);
402 
403 /*
404  * Memory registration functions used in start/stop device callbacks
405  */
406 void vhost_session_mem_register(struct rte_vhost_memory *mem);
407 void vhost_session_mem_unregister(struct rte_vhost_memory *mem);
408 
409 /*
410  * Call a function for each session of the provided vhost device.
411  * The function will be called one-by-one on each session's thread.
412  *
413  * \param vdev vhost device
414  * \param fn function to call on each session's thread
415  * \param cpl_fn function to be called at the end of the iteration on
416  * the vhost management thread.
417  * Optional, can be NULL.
418  * \param arg additional argument to the both callbacks
419  */
420 void vhost_user_dev_foreach_session(struct spdk_vhost_dev *dev,
421 				    spdk_vhost_session_fn fn,
422 				    spdk_vhost_dev_fn cpl_fn,
423 				    void *arg);
424 
425 /**
426  * Call a function on the provided lcore and block until either
427  * vhost_user_session_start_done() or vhost_user_session_stop_done()
428  * is called.
429  *
430  * This must be called under the global vhost mutex, which this function
431  * will unlock for the time it's waiting. It's meant to be called only
432  * from start/stop session callbacks.
433  *
434  * \param vsession vhost session
435  * \param cb_fn the function to call. The void *arg parameter in cb_fn
436  * is always NULL.
437  * \param timeout_sec timeout in seconds. This function will still
438  * block after the timeout expires, but will print the provided errmsg.
439  * \param errmsg error message to print once the timeout expires
440  * \return return the code passed to spdk_vhost_session_event_done().
441  */
442 int vhost_user_session_send_event(struct spdk_vhost_session *vsession,
443 				  spdk_vhost_session_fn cb_fn, unsigned timeout_sec,
444 				  const char *errmsg);
445 
446 /**
447  * Finish a blocking spdk_vhost_user_session_send_event() call and finally
448  * start the session. This must be called on the target lcore, which
449  * will now receive all session-related messages (e.g. from
450  * vhost_user_dev_foreach_session()).
451  *
452  * Must be called under the global vhost lock.
453  *
454  * \param vsession vhost session
455  * \param response return code
456  */
457 void vhost_user_session_start_done(struct spdk_vhost_session *vsession, int response);
458 
459 /**
460  * Finish a blocking spdk_vhost_user_session_send_event() call and finally
461  * stop the session. This must be called on the session's lcore which
462  * used to receive all session-related messages (e.g. from
463  * vhost_user_dev_foreach_session()). After this call, the session-
464  * related messages will be once again processed by any arbitrary thread.
465  *
466  * Must be called under the global vhost lock.
467  *
468  * Must be called under the global vhost mutex.
469  *
470  * \param vsession vhost session
471  * \param response return code
472  */
473 void vhost_user_session_stop_done(struct spdk_vhost_session *vsession, int response);
474 
475 struct spdk_vhost_session *vhost_session_find_by_vid(int vid);
476 void vhost_session_install_rte_compat_hooks(struct spdk_vhost_session *vsession);
477 int vhost_register_unix_socket(const char *path, const char *ctrl_name,
478 			       uint64_t virtio_features, uint64_t disabled_features, uint64_t protocol_features);
479 int vhost_driver_unregister(const char *path);
480 int vhost_get_mem_table(int vid, struct rte_vhost_memory **mem);
481 int vhost_get_negotiated_features(int vid, uint64_t *negotiated_features);
482 
483 int remove_vhost_controller(struct spdk_vhost_dev *vdev);
484 
485 struct spdk_io_channel *vhost_blk_get_io_channel(struct spdk_vhost_dev *vdev);
486 void vhost_blk_put_io_channel(struct spdk_io_channel *ch);
487 
488 /* The spdk_bdev pointer should only be used to retrieve
489  * the device properties, ex. number of blocks or I/O type supported. */
490 struct spdk_bdev *vhost_blk_get_bdev(struct spdk_vhost_dev *vdev);
491 
492 /* Function calls from vhost.c to rte_vhost_user.c,
493  * shall removed once virtio transport abstraction is complete. */
494 int vhost_user_session_set_coalescing(struct spdk_vhost_dev *dev,
495 				      struct spdk_vhost_session *vsession, void *ctx);
496 int vhost_user_dev_set_coalescing(struct spdk_vhost_user_dev *user_dev, uint32_t delay_base_us,
497 				  uint32_t iops_threshold);
498 int vhost_user_dev_register(struct spdk_vhost_dev *vdev, const char *name,
499 			    struct spdk_cpuset *cpumask, const struct spdk_vhost_user_dev_backend *user_backend);
500 int vhost_user_dev_unregister(struct spdk_vhost_dev *vdev);
501 int vhost_user_init(void);
502 void vhost_user_fini(spdk_vhost_fini_cb vhost_cb);
503 
504 int virtio_blk_construct_ctrlr(struct spdk_vhost_dev *vdev, const char *address,
505 			       struct spdk_cpuset *cpumask, const struct spdk_json_val *params,
506 			       const struct spdk_vhost_user_dev_backend *user_backend);
507 int virtio_blk_destroy_ctrlr(struct spdk_vhost_dev *vdev);
508 
509 struct spdk_vhost_blk_task;
510 
511 typedef void (*virtio_blk_request_cb)(uint8_t status, struct spdk_vhost_blk_task *task,
512 				      void *cb_arg);
513 
514 struct spdk_vhost_blk_task {
515 	struct spdk_bdev_io *bdev_io;
516 	virtio_blk_request_cb cb;
517 	void *cb_arg;
518 
519 	volatile uint8_t *status;
520 
521 	/* for io wait */
522 	struct spdk_bdev_io_wait_entry bdev_io_wait;
523 	struct spdk_io_channel *bdev_io_wait_ch;
524 	struct spdk_vhost_dev *bdev_io_wait_vdev;
525 
526 	/** Number of bytes that were written. */
527 	uint32_t used_len;
528 	uint16_t iovcnt;
529 	struct iovec iovs[SPDK_VHOST_IOVS_MAX];
530 
531 	/** Size of whole payload in bytes */
532 	uint32_t payload_size;
533 };
534 
535 int virtio_blk_process_request(struct spdk_vhost_dev *vdev, struct spdk_io_channel *ch,
536 			       struct spdk_vhost_blk_task *task, virtio_blk_request_cb cb, void *cb_arg);
537 
538 typedef void (*bdev_event_cb_complete)(struct spdk_vhost_dev *vdev, void *ctx);
539 
540 #define SPDK_VIRTIO_BLK_TRSTRING_MAX_LEN 32
541 
542 struct spdk_virtio_blk_transport_ops {
543 	/**
544 	 * Transport name
545 	 */
546 	char name[SPDK_VIRTIO_BLK_TRSTRING_MAX_LEN];
547 
548 	/**
549 	 * Create a transport for the given transport opts
550 	 */
551 	struct spdk_virtio_blk_transport *(*create)(const struct spdk_json_val *params);
552 
553 	/**
554 	 * Dump transport-specific opts into JSON
555 	 */
556 	void (*dump_opts)(struct spdk_virtio_blk_transport *transport, struct spdk_json_write_ctx *w);
557 
558 	/**
559 	 * Destroy the transport
560 	 */
561 	int (*destroy)(struct spdk_virtio_blk_transport *transport,
562 		       spdk_vhost_fini_cb cb_fn);
563 
564 	/**
565 	 * Create vhost block controller
566 	 */
567 	int (*create_ctrlr)(struct spdk_vhost_dev *vdev, struct spdk_cpuset *cpumask,
568 			    const char *address, const struct spdk_json_val *params,
569 			    void *custom_opts);
570 
571 	/**
572 	 * Destroy vhost block controller
573 	 */
574 	int (*destroy_ctrlr)(struct spdk_vhost_dev *vdev);
575 
576 	/*
577 	 * Signal removal of the bdev.
578 	 */
579 	void (*bdev_event)(enum spdk_bdev_event_type type, struct spdk_vhost_dev *vdev,
580 			   bdev_event_cb_complete cb, void *cb_arg);
581 };
582 
583 struct spdk_virtio_blk_transport {
584 	const struct spdk_virtio_blk_transport_ops	*ops;
585 	TAILQ_ENTRY(spdk_virtio_blk_transport)		tailq;
586 };
587 
588 struct virtio_blk_transport_ops_list_element {
589 	struct spdk_virtio_blk_transport_ops			ops;
590 	TAILQ_ENTRY(virtio_blk_transport_ops_list_element)	link;
591 };
592 
593 void virtio_blk_transport_register(const struct spdk_virtio_blk_transport_ops *ops);
594 int virtio_blk_transport_create(const char *transport_name, const struct spdk_json_val *params);
595 int virtio_blk_transport_destroy(struct spdk_virtio_blk_transport *transport,
596 				 spdk_vhost_fini_cb cb_fn);
597 
598 const struct spdk_virtio_blk_transport_ops *virtio_blk_get_transport_ops(
599 	const char *transport_name);
600 
601 
602 /*
603  * Macro used to register new transports.
604  */
605 #define SPDK_VIRTIO_BLK_TRANSPORT_REGISTER(name, transport_ops) \
606 static void __attribute__((constructor)) _virtio_blk_transport_register_##name(void) \
607 { \
608 	virtio_blk_transport_register(transport_ops); \
609 }
610 
611 #endif /* SPDK_VHOST_INTERNAL_H */
612