LCOV - code coverage report
Current view: top level - include/spdk - thread.h (source / functions) Hit Total Coverage
Test: ut_cov_unit.info Lines: 9 10 90.0 %
Date: 2024-12-16 11:30:48 Functions: 2 2 100.0 %

          Line data    Source code
       1             : /*   SPDX-License-Identifier: BSD-3-Clause
       2             :  *   Copyright (C) 2016 Intel Corporation.
       3             :  *   All rights reserved.
       4             :  *   Copyright (c) 2022, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
       5             :  */
       6             : 
       7             : /** \file
       8             :  * Thread
       9             :  */
      10             : 
      11             : #ifndef SPDK_THREAD_H_
      12             : #define SPDK_THREAD_H_
      13             : 
      14             : #ifdef __linux__
      15             : #include <sys/epoll.h>
      16             : #endif
      17             : 
      18             : #include "spdk/fd_group.h"
      19             : #include "spdk/stdinc.h"
      20             : #include "spdk/assert.h"
      21             : #include "spdk/cpuset.h"
      22             : #include "spdk/env.h"
      23             : #include "spdk/util.h"
      24             : #include "spdk/likely.h"
      25             : 
      26             : #ifdef __cplusplus
      27             : extern "C" {
      28             : #endif
      29             : 
      30             : /**
      31             :  * Pollers should always return a value of this type
      32             :  * indicating whether they did real work or not.
      33             :  */
      34             : enum spdk_thread_poller_rc {
      35             :         SPDK_POLLER_IDLE,
      36             :         SPDK_POLLER_BUSY,
      37             : };
      38             : 
      39             : /**
      40             :  * A stackless, lightweight thread.
      41             :  */
      42             : struct spdk_thread;
      43             : 
      44             : /**
      45             :  * A function repeatedly called on the same spdk_thread.
      46             :  */
      47             : struct spdk_poller;
      48             : 
      49             : struct spdk_io_channel_iter;
      50             : 
      51             : /**
      52             :  * A function that is called each time a new thread is created.
      53             :  * The implementer of this function should frequently call
      54             :  * spdk_thread_poll() on the thread provided.
      55             :  *
      56             :  * \param thread The new spdk_thread.
      57             :  */
      58             : typedef int (*spdk_new_thread_fn)(struct spdk_thread *thread);
      59             : 
      60             : /**
      61             :  * SPDK thread operation type.
      62             :  */
      63             : enum spdk_thread_op {
      64             :         /* Called each time a new thread is created. The implementer of this operation
      65             :          * should frequently call spdk_thread_poll() on the thread provided.
      66             :          */
      67             :         SPDK_THREAD_OP_NEW,
      68             : 
      69             :         /* Called when SPDK thread needs to be rescheduled. (e.g., when cpumask of the
      70             :          * SPDK thread is updated.
      71             :          */
      72             :         SPDK_THREAD_OP_RESCHED,
      73             : };
      74             : 
      75             : /**
      76             :  * Function to be called for SPDK thread operation.
      77             :  */
      78             : typedef int (*spdk_thread_op_fn)(struct spdk_thread *thread, enum spdk_thread_op op);
      79             : 
      80             : /**
      81             :  * Function to check whether the SPDK thread operation is supported.
      82             :  */
      83             : typedef bool (*spdk_thread_op_supported_fn)(enum spdk_thread_op op);
      84             : 
      85             : /**
      86             :  * A function that will be called on the target thread.
      87             :  *
      88             :  * \param ctx Context passed as arg to spdk_thread_pass_msg().
      89             :  */
      90             : typedef void (*spdk_msg_fn)(void *ctx);
      91             : 
      92             : /**
      93             :  * Function to be called to pass a message to a thread.
      94             :  *
      95             :  * \param fn Callback function for a thread.
      96             :  * \param ctx Context passed to fn.
      97             :  * \param thread_ctx Context for the thread.
      98             :  */
      99             : typedef void (*spdk_thread_pass_msg)(spdk_msg_fn fn, void *ctx,
     100             :                                      void *thread_ctx);
     101             : 
     102             : /**
     103             :  * Callback function for a poller.
     104             :  *
     105             :  * \param ctx Context passed as arg to spdk_poller_register().
     106             :  * \return value of type `enum spdk_thread_poller_rc` (ex: SPDK_POLLER_IDLE
     107             :  * if no work was done or SPDK_POLLER_BUSY if work was done.)
     108             :  */
     109             : typedef int (*spdk_poller_fn)(void *ctx);
     110             : 
     111             : /**
     112             :  * Callback function to set poller into interrupt mode or back to poll mode.
     113             :  *
     114             :  * \param poller Poller to set interrupt or poll mode.
     115             :  * \param cb_arg Argument passed to the callback function.
     116             :  * \param interrupt_mode Set interrupt mode for true, or poll mode for false
     117             :  */
     118             : typedef void (*spdk_poller_set_interrupt_mode_cb)(struct spdk_poller *poller, void *cb_arg,
     119             :                 bool interrupt_mode);
     120             : 
     121             : /**
     122             :  * Mark that the poller is capable of entering interrupt mode.
     123             :  *
     124             :  * When registering the poller set interrupt callback, the callback will get
     125             :  * executed immediately if its spdk_thread is in the interrupt mode.
     126             :  *
     127             :  * Callers may pass NULL for the cb_fn, signifying that no callback is
     128             :  * necessary when the interrupt mode changes.
     129             :  *
     130             :  * \param poller The poller to register callback function.
     131             :  * \param cb_fn Callback function called when the poller must transition into or out of interrupt mode
     132             :  * \param cb_arg Argument passed to the callback function.
     133             :  */
     134             : void spdk_poller_register_interrupt(struct spdk_poller *poller,
     135             :                                     spdk_poller_set_interrupt_mode_cb cb_fn,
     136             :                                     void *cb_arg);
     137             : 
     138             : /**
     139             :  * I/O channel creation callback.
     140             :  *
     141             :  * \param io_device I/O device associated with this channel.
     142             :  * \param ctx_buf Context for the I/O device.
     143             :  */
     144             : typedef int (*spdk_io_channel_create_cb)(void *io_device, void *ctx_buf);
     145             : 
     146             : /**
     147             :  * I/O channel destruction callback.
     148             :  *
     149             :  * \param io_device I/O device associated with this channel.
     150             :  * \param ctx_buf Context for the I/O device.
     151             :  */
     152             : typedef void (*spdk_io_channel_destroy_cb)(void *io_device, void *ctx_buf);
     153             : 
     154             : /**
     155             :  * I/O device unregister callback.
     156             :  *
     157             :  * \param io_device Unregistered I/O device.
     158             :  */
     159             : typedef void (*spdk_io_device_unregister_cb)(void *io_device);
     160             : 
     161             : /**
     162             :  * Called on the appropriate thread for each channel associated with io_device.
     163             :  *
     164             :  * \param i I/O channel iterator.
     165             :  */
     166             : typedef void (*spdk_channel_msg)(struct spdk_io_channel_iter *i);
     167             : 
     168             : /**
     169             :  * spdk_for_each_channel() callback.
     170             :  *
     171             :  * \param i I/O channel iterator.
     172             :  * \param status 0 if it completed successfully, or negative errno if it failed.
     173             :  */
     174             : typedef void (*spdk_channel_for_each_cpl)(struct spdk_io_channel_iter *i, int status);
     175             : 
     176             : #define SPDK_IO_CHANNEL_STRUCT_SIZE     96
     177             : 
     178             : /**
     179             :  * Message memory pool size definitions
     180             :  */
     181             : #define SPDK_MSG_MEMPOOL_CACHE_SIZE     1024
     182             : /* Power of 2 minus 1 is optimal for memory consumption */
     183             : #define SPDK_DEFAULT_MSG_MEMPOOL_SIZE (262144 - 1)
     184             : 
     185             : /**
     186             :  * Initialize the threading library. Must be called once prior to allocating any threads.
     187             :  *
     188             :  * \param new_thread_fn Called each time a new SPDK thread is created. The implementer
     189             :  * is expected to frequently call spdk_thread_poll() on the provided thread.
     190             :  * \param ctx_sz For each thread allocated, an additional region of memory of
     191             :  * size ctx_size will also be allocated, for use by the thread scheduler. A pointer
     192             :  * to this region may be obtained by calling spdk_thread_get_ctx().
     193             :  *
     194             :  * \return 0 on success. Negated errno on failure.
     195             :  */
     196             : int spdk_thread_lib_init(spdk_new_thread_fn new_thread_fn, size_t ctx_sz);
     197             : 
     198             : /**
     199             :  * Initialize the threading library. Must be called once prior to allocating any threads
     200             :  *
     201             :  * Both thread_op_fn and thread_op_type_supported_fn have to be specified or not
     202             :  * specified together.
     203             :  *
     204             :  * \param thread_op_fn Called for SPDK thread operation.
     205             :  * \param thread_op_supported_fn Called to check whether the SPDK thread operation is supported.
     206             :  * \param ctx_sz For each thread allocated, for use by the thread scheduler. A pointer
     207             :  * to this region may be obtained by calling spdk_thread_get_ctx().
     208             :  * \param msg_mempool_size Size of the allocated spdk_msg_mempool.
     209             :  *
     210             :  * \return 0 on success. Negated errno on failure.
     211             :  */
     212             : int spdk_thread_lib_init_ext(spdk_thread_op_fn thread_op_fn,
     213             :                              spdk_thread_op_supported_fn thread_op_supported_fn,
     214             :                              size_t ctx_sz, size_t msg_mempool_size);
     215             : 
     216             : /**
     217             :  * Release all resources associated with this library.
     218             :  */
     219             : void spdk_thread_lib_fini(void);
     220             : 
     221             : /**
     222             :  * Creates a new SPDK thread object.
     223             :  *
     224             :  * Note that the first thread created via spdk_thread_create() will be designated as
     225             :  * the app thread.  Other SPDK libraries may place restrictions on certain APIs to
     226             :  * only be called in the context of this app thread.
     227             :  *
     228             :  * \param name Human-readable name for the thread; can be retrieved with spdk_thread_get_name().
     229             :  * The string is copied, so the pointed-to data only needs to be valid during the
     230             :  * spdk_thread_create() call. May be NULL to specify no name.
     231             :  * \param cpumask Optional mask of CPU cores on which to schedule this thread. This is only
     232             :  * a suggestion to the scheduler. The value is copied, so cpumask may be released when
     233             :  * this function returns. May be NULL if no mask is required.
     234             :  *
     235             :  * \return a pointer to the allocated thread on success or NULL on failure..
     236             :  */
     237             : struct spdk_thread *spdk_thread_create(const char *name, const struct spdk_cpuset *cpumask);
     238             : 
     239             : /**
     240             :  * Return the app thread.
     241             :  *
     242             :  * The app thread is the first thread created using spdk_thread_create().
     243             :  *
     244             :  * \return a pointer to the app thread, or NULL if no thread has been created yet.
     245             :  */
     246             : struct spdk_thread *spdk_thread_get_app_thread(void);
     247             : 
     248             : /**
     249             :  * Check if the specified spdk_thread is the app thread.
     250             :  *
     251             :  * \param thread The thread to check. If NULL, check the current spdk_thread.
     252             :  * \return true if the specified spdk_thread is the app thread, false otherwise.
     253             :  */
     254             : bool spdk_thread_is_app_thread(struct spdk_thread *thread);
     255             : 
     256             : /**
     257             :  * Force the current system thread to act as if executing the given SPDK thread.
     258             :  *
     259             :  * \param thread The thread to set.
     260             :  */
     261             : void spdk_set_thread(struct spdk_thread *thread);
     262             : 
     263             : /**
     264             :  * Bind or unbind spdk_thread to its current CPU core.
     265             :  *
     266             :  * If spdk_thread is bound, it couldn't be rescheduled to other CPU cores until it is unbound.
     267             :  *
     268             :  * \param thread The thread to bind or not.
     269             :  * \param bind true for bind, false for unbind.
     270             :  */
     271             : void spdk_thread_bind(struct spdk_thread *thread, bool bind);
     272             : 
     273             : /**
     274             :  * Returns whether the thread is bound to its current CPU core.
     275             :  *
     276             :  * \param thread The thread to query.
     277             :  *
     278             :  * \return true if bound, false otherwise
     279             :  */
     280             : bool spdk_thread_is_bound(struct spdk_thread *thread);
     281             : 
     282             : /**
     283             :  * Mark the thread as exited, failing all future spdk_thread_send_msg(),
     284             :  * spdk_poller_register(), and spdk_get_io_channel() calls. May only be called
     285             :  * within an spdk poller or message.
     286             :  *
     287             :  * All I/O channel references associated with the thread must be released
     288             :  * using spdk_put_io_channel(), and all active pollers associated with the thread
     289             :  * should be unregistered using spdk_poller_unregister(), prior to calling
     290             :  * this function. This function will complete these processing. The completion can
     291             :  * be queried by spdk_thread_is_exited().
     292             :  *
     293             :  * Note that this function must not be called on the app thread until after it
     294             :  * has been called for all other threads.
     295             :  *
     296             :  * \param thread The thread to exit.
     297             :  *
     298             :  * \return always 0. (return value was deprecated but keep it for ABI compatibility.)
     299             :  */
     300             : int spdk_thread_exit(struct spdk_thread *thread);
     301             : 
     302             : /**
     303             :  * Returns whether the thread is marked as exited.
     304             :  *
     305             :  * A thread is exited only after it has spdk_thread_exit() called on it, and
     306             :  * it has been polled until any outstanding operations targeting this
     307             :  * thread have completed.  This may include poller unregistrations, io channel
     308             :  * unregistrations, or outstanding spdk_thread_send_msg calls.
     309             :  *
     310             :  * \param thread The thread to query.
     311             :  *
     312             :  * \return true if marked as exited, false otherwise.
     313             :  */
     314             : bool spdk_thread_is_exited(struct spdk_thread *thread);
     315             : 
     316             : /**
     317             :  * Returns whether the thread is still running.
     318             :  *
     319             :  * A thread is considered running until it has * spdk_thread_exit() called on it.
     320             :  *
     321             :  * \param thread The thread to query.
     322             :  *
     323             :  * \return true if still running, false otherwise.
     324             :  */
     325             : bool spdk_thread_is_running(struct spdk_thread *thread);
     326             : 
     327             : /**
     328             :  * Destroy a thread, releasing all of its resources. May only be called
     329             :  * on a thread previously marked as exited.
     330             :  *
     331             :  * \param thread The thread to destroy.
     332             :  *
     333             :  */
     334             : void spdk_thread_destroy(struct spdk_thread *thread);
     335             : 
     336             : /**
     337             :  * Return a pointer to this thread's context.
     338             :  *
     339             :  * \param thread The thread on which to get the context.
     340             :  *
     341             :  * \return a pointer to the per-thread context, or NULL if there is
     342             :  * no per-thread context.
     343             :  */
     344             : void *spdk_thread_get_ctx(struct spdk_thread *thread);
     345             : 
     346             : /**
     347             :  * Get the thread's cpumask.
     348             :  *
     349             :  * \param thread The thread to get the cpumask for.
     350             :  *
     351             :  * \return cpuset pointer
     352             :  */
     353             : struct spdk_cpuset *spdk_thread_get_cpumask(struct spdk_thread *thread);
     354             : 
     355             : /**
     356             :  * Set the current thread's cpumask to the specified value. The thread may be
     357             :  * rescheduled to one of the CPUs specified in the cpumask.
     358             :  *
     359             :  * This API requires SPDK thread operation supports SPDK_THREAD_OP_RESCHED.
     360             :  *
     361             :  * \param cpumask The new cpumask for the thread.
     362             :  *
     363             :  * \return 0 on success, negated errno otherwise.
     364             :  */
     365             : int spdk_thread_set_cpumask(struct spdk_cpuset *cpumask);
     366             : 
     367             : /**
     368             :  * Return the thread object associated with the context handle previously
     369             :  * obtained by calling spdk_thread_get_ctx().
     370             :  *
     371             :  * \param ctx A context previously obtained by calling spdk_thread_get_ctx()
     372             :  *
     373             :  * \return The associated thread.
     374             :  */
     375             : struct spdk_thread *spdk_thread_get_from_ctx(void *ctx);
     376             : 
     377             : /**
     378             :  * Perform one iteration worth of processing on the thread. This includes
     379             :  * both expired and continuous pollers as well as messages. If the thread
     380             :  * has exited, return immediately.
     381             :  *
     382             :  * \param thread The thread to process
     383             :  * \param max_msgs The maximum number of messages that will be processed.
     384             :  *                 Use 0 to process the default number of messages (8).
     385             :  * \param now The current time, in ticks. Optional. If 0 is passed, this
     386             :  *            function will call spdk_get_ticks() to get the current time.
     387             :  *            The current time is used as start time and this function
     388             :  *            will call spdk_get_ticks() at its end to know end time to
     389             :  *            measure run time of this function.
     390             :  *
     391             :  * \return 1 if work was done. 0 if no work was done.
     392             :  */
     393             : int spdk_thread_poll(struct spdk_thread *thread, uint32_t max_msgs, uint64_t now);
     394             : 
     395             : /**
     396             :  * Return the number of ticks until the next timed poller
     397             :  * would expire. Timed pollers are pollers for which
     398             :  * period_microseconds is greater than 0.
     399             :  *
     400             :  * \param thread The thread to check poller expiration times on
     401             :  *
     402             :  * \return Number of ticks. If no timed pollers, return 0.
     403             :  */
     404             : uint64_t spdk_thread_next_poller_expiration(struct spdk_thread *thread);
     405             : 
     406             : /**
     407             :  * Returns whether there are any active pollers (pollers for which
     408             :  * period_microseconds equals 0) registered to be run on the thread.
     409             :  *
     410             :  * \param thread The thread to check.
     411             :  *
     412             :  * \return 1 if there is at least one active poller, 0 otherwise.
     413             :  */
     414             : int spdk_thread_has_active_pollers(struct spdk_thread *thread);
     415             : 
     416             : /**
     417             :  * Returns whether there are any pollers registered to be run
     418             :  * on the thread.
     419             :  *
     420             :  * \param thread The thread to check.
     421             :  *
     422             :  * \return true if there is any active poller, false otherwise.
     423             :  */
     424             : bool spdk_thread_has_pollers(struct spdk_thread *thread);
     425             : 
     426             : /**
     427             :  * Returns whether there are scheduled operations to be run on the thread.
     428             :  *
     429             :  * \param thread The thread to check.
     430             :  *
     431             :  * \return true if there are no scheduled operations, false otherwise.
     432             :  */
     433             : bool spdk_thread_is_idle(struct spdk_thread *thread);
     434             : 
     435             : /**
     436             :  * Get count of allocated threads.
     437             :  */
     438             : uint32_t spdk_thread_get_count(void);
     439             : 
     440             : /**
     441             :  * Get a handle to the current thread.
     442             :  *
     443             :  * This handle may be passed to other threads and used as the target of
     444             :  * spdk_thread_send_msg().
     445             :  *
     446             :  * \sa spdk_io_channel_get_thread()
     447             :  *
     448             :  * \return a pointer to the current thread on success or NULL on failure.
     449             :  */
     450             : struct spdk_thread *spdk_get_thread(void);
     451             : 
     452             : /**
     453             :  * Get a thread's name.
     454             :  *
     455             :  * \param thread Thread to query.
     456             :  *
     457             :  * \return the name of the thread.
     458             :  */
     459             : const char *spdk_thread_get_name(const struct spdk_thread *thread);
     460             : 
     461             : /**
     462             :  * Get a thread's ID.
     463             :  *
     464             :  * \param thread Thread to query.
     465             :  *
     466             :  * \return the ID of the thread..
     467             :  */
     468             : uint64_t spdk_thread_get_id(const struct spdk_thread *thread);
     469             : 
     470             : /**
     471             :  * Get the thread by the ID.
     472             :  *
     473             :  * \param id ID of the thread.
     474             :  * \return Thread whose ID matches or NULL otherwise.
     475             :  */
     476             : struct spdk_thread *spdk_thread_get_by_id(uint64_t id);
     477             : 
     478             : struct spdk_thread_stats {
     479             :         uint64_t busy_tsc;
     480             :         uint64_t idle_tsc;
     481             : };
     482             : 
     483             : /**
     484             :  * Get statistics about the current thread.
     485             :  *
     486             :  * Copy cumulative thread stats values to the provided thread stats structure.
     487             :  *
     488             :  * \param stats User's thread_stats structure.
     489             :  */
     490             : int spdk_thread_get_stats(struct spdk_thread_stats *stats);
     491             : 
     492             : /**
     493             :  * Return the TSC value from the end of the last time this thread was polled.
     494             :  *
     495             :  * \param thread Thread to query.  If NULL, use current thread.
     496             :  *
     497             :  * \return TSC value from the end of the last time this thread was polled.
     498             :  */
     499             : uint64_t spdk_thread_get_last_tsc(struct spdk_thread *thread);
     500             : 
     501             : /**
     502             :  * Send a message to the given thread.
     503             :  *
     504             :  * The message will be sent asynchronously - i.e. spdk_thread_send_msg will always return
     505             :  * prior to `fn` being called.
     506             :  *
     507             :  * \param thread The target thread.
     508             :  * \param fn This function will be called on the given thread.
     509             :  * \param ctx This context will be passed to fn when called.
     510             :  *
     511             :  * \return 0 on success
     512             :  * \return -ENOMEM if the message could not be allocated
     513             :  * \return -EIO if the message could not be sent to the destination thread
     514             :  */
     515             : int spdk_thread_send_msg(const struct spdk_thread *thread, spdk_msg_fn fn, void *ctx);
     516             : 
     517             : /**
     518             :  * Send a message to the given thread. Only one critical message can be outstanding at the same
     519             :  * time. It's intended to use this function in any cases that might interrupt the execution of the
     520             :  * application, such as signal handlers.
     521             :  *
     522             :  * The message will be sent asynchronously - i.e. spdk_thread_send_critical_msg will always return
     523             :  * prior to `fn` being called.
     524             :  *
     525             :  * \param thread The target thread.
     526             :  * \param fn This function will be called on the given thread.
     527             :  *
     528             :  * \return 0 on success
     529             :  * \return -EIO if the message could not be sent to the destination thread, due to an already
     530             :  * outstanding critical message
     531             :  */
     532             : int spdk_thread_send_critical_msg(struct spdk_thread *thread, spdk_msg_fn fn);
     533             : 
     534             : /**
     535             :  * Run the msg callback on the given thread. If this happens to be the current
     536             :  * thread, the callback is executed immediately; otherwise a message is sent to
     537             :  * the thread, and it's run asynchronously.
     538             :  *
     539             :  * \param thread The target thread.
     540             :  * \param fn This function will be called on the given thread.
     541             :  * \param ctx This context will be passed to fn when called.
     542             :  *
     543             :  * \return 0 on success
     544             :  * \return -ENOMEM if the message could not be allocated
     545             :  * \return -EIO if the message could not be sent to the destination thread
     546             :  */
     547             : static inline int
     548         116 : spdk_thread_exec_msg(const struct spdk_thread *thread, spdk_msg_fn fn, void *ctx)
     549             : {
     550         116 :         assert(thread != NULL);
     551             : 
     552         116 :         if (spdk_get_thread() == thread) {
     553         114 :                 fn(ctx);
     554         114 :                 return 0;
     555             :         }
     556             : 
     557           2 :         return spdk_thread_send_msg(thread, fn, ctx);
     558             : }
     559             : 
     560             : /**
     561             :  * Send a message to each thread, serially.
     562             :  *
     563             :  * The message is sent asynchronously - i.e. spdk_for_each_thread will return
     564             :  * prior to `fn` being called on each thread.
     565             :  *
     566             :  * \param fn This is the function that will be called on each thread.
     567             :  * \param ctx This context will be passed to fn when called.
     568             :  * \param cpl This will be called on the originating thread after `fn` has been
     569             :  * called on each thread.
     570             :  */
     571             : void spdk_for_each_thread(spdk_msg_fn fn, void *ctx, spdk_msg_fn cpl);
     572             : 
     573             : /**
     574             :  * Set current spdk_thread into interrupt mode or back to poll mode.
     575             :  *
     576             :  * Only valid when thread interrupt facility is enabled by
     577             :  * spdk_interrupt_mode_enable().
     578             :  *
     579             :  * \param enable_interrupt Set interrupt mode for true, or poll mode for false
     580             :  */
     581             : void spdk_thread_set_interrupt_mode(bool enable_interrupt);
     582             : 
     583             : /**
     584             :  * Register a poller on the current thread.
     585             :  *
     586             :  * The poller can be unregistered by calling spdk_poller_unregister().
     587             :  *
     588             :  * \param fn This function will be called every `period_microseconds`.
     589             :  * \param arg Argument passed to fn.
     590             :  * \param period_microseconds How often to call `fn`. If 0, call `fn` as often
     591             :  *  as possible.
     592             :  *
     593             :  * \return a pointer to the poller registered on the current thread on success
     594             :  * or NULL on failure.
     595             :  */
     596             : struct spdk_poller *spdk_poller_register(spdk_poller_fn fn,
     597             :                 void *arg,
     598             :                 uint64_t period_microseconds);
     599             : 
     600             : /**
     601             :  * Register a poller on the current thread with arbitrary name.
     602             :  *
     603             :  * The poller can be unregistered by calling spdk_poller_unregister().
     604             :  *
     605             :  * \param fn This function will be called every `period_microseconds`.
     606             :  * \param arg Argument passed to fn.
     607             :  * \param period_microseconds How often to call `fn`. If 0, call `fn` as often
     608             :  *  as possible.
     609             :  * \param name Human readable name for the poller. Pointer of the poller function
     610             :  * name is set if NULL.
     611             :  *
     612             :  * \return a pointer to the poller registered on the current thread on success
     613             :  * or NULL on failure.
     614             :  */
     615             : struct spdk_poller *spdk_poller_register_named(spdk_poller_fn fn,
     616             :                 void *arg,
     617             :                 uint64_t period_microseconds,
     618             :                 const char *name);
     619             : 
     620             : /*
     621             :  * \brief Register a poller on the current thread with setting its name
     622             :  * to the string of the poller function name. The poller being registered
     623             :  * should return a value of type `enum spdk_thread_poller_rc`. See
     624             :  * \ref spdk_poller_fn for more information.
     625             :  */
     626             : #define SPDK_POLLER_REGISTER(fn, arg, period_microseconds)      \
     627             :         spdk_poller_register_named(fn, arg, period_microseconds, #fn)
     628             : 
     629             : /**
     630             :  * Unregister a poller on the current thread.
     631             :  *
     632             :  * This function will also write NULL to the spdk_poller pointer pointed
     633             :  * to by ppoller, to help encourage a poller pointer not getting reused
     634             :  * after it has been unregistered.
     635             :  *
     636             :  * It is OK to pass a ppoller parameter that points to NULL, in this case
     637             :  * the function is a nop.
     638             :  *
     639             :  * \param ppoller The poller to unregister.
     640             :  */
     641             : void spdk_poller_unregister(struct spdk_poller **ppoller);
     642             : 
     643             : /**
     644             :  * Pause a poller on the current thread.
     645             :  *
     646             :  * The poller is not run until it is resumed with spdk_poller_resume().  It is
     647             :  * perfectly fine to pause an already paused poller.
     648             :  *
     649             :  * \param poller The poller to pause.
     650             :  */
     651             : void spdk_poller_pause(struct spdk_poller *poller);
     652             : 
     653             : /**
     654             :  * Resume a poller on the current thread.
     655             :  *
     656             :  * Resumes a poller paused with spdk_poller_pause().  It is perfectly fine to
     657             :  * resume an unpaused poller.
     658             :  *
     659             :  * \param poller The poller to resume.
     660             :  */
     661             : void spdk_poller_resume(struct spdk_poller *poller);
     662             : 
     663             : /**
     664             :  * Register the opaque io_device context as an I/O device.
     665             :  *
     666             :  * After an I/O device is registered, it can return I/O channels using the
     667             :  * spdk_get_io_channel() function.
     668             :  *
     669             :  * \param io_device The pointer to io_device context.
     670             :  * \param create_cb Callback function invoked to allocate any resources required
     671             :  * for a new I/O channel.
     672             :  * \param destroy_cb Callback function invoked to release the resources for an
     673             :  * I/O channel.
     674             :  * \param ctx_size The size of the context buffer allocated to store references
     675             :  * to allocated I/O channel resources.
     676             :  * \param name A string name for the device used only for debugging. Optional -
     677             :  * may be NULL.
     678             :  */
     679             : void spdk_io_device_register(void *io_device, spdk_io_channel_create_cb create_cb,
     680             :                              spdk_io_channel_destroy_cb destroy_cb, uint32_t ctx_size,
     681             :                              const char *name);
     682             : 
     683             : /**
     684             :  * Unregister the opaque io_device context as an I/O device.
     685             :  *
     686             :  * The actual unregistration might be deferred until all active I/O channels are
     687             :  * destroyed.
     688             :  *
     689             :  * \param io_device The pointer to io_device context.
     690             :  * \param unregister_cb An optional callback function invoked to release any
     691             :  * references to this I/O device.
     692             :  */
     693             : void spdk_io_device_unregister(void *io_device, spdk_io_device_unregister_cb unregister_cb);
     694             : 
     695             : /**
     696             :  * Get an I/O channel for the specified io_device to be used by the calling thread.
     697             :  *
     698             :  * The io_device context pointer specified must have previously been registered
     699             :  * using spdk_io_device_register(). If an existing I/O channel does not exist
     700             :  * yet for the given io_device on the calling thread, it will allocate an I/O
     701             :  * channel and invoke the create_cb function pointer specified in spdk_io_device_register().
     702             :  * If an I/O channel already exists for the given io_device on the calling thread,
     703             :  * its reference is returned rather than creating a new I/O channel.
     704             :  *
     705             :  * \param io_device The pointer to io_device context.
     706             :  *
     707             :  * \return a pointer to the I/O channel for this device on success or NULL on failure.
     708             :  */
     709             : struct spdk_io_channel *spdk_get_io_channel(void *io_device);
     710             : 
     711             : /**
     712             :  * Release a reference to an I/O channel. This happens asynchronously.
     713             :  *
     714             :  * This must be called on the same thread that called spdk_get_io_channel()
     715             :  * for the specified I/O channel. If this releases the last reference to the
     716             :  * I/O channel, The destroy_cb function specified in spdk_io_device_register()
     717             :  * will be invoked to release any associated resources.
     718             :  *
     719             :  * \param ch I/O channel to release a reference.
     720             :  */
     721             : void spdk_put_io_channel(struct spdk_io_channel *ch);
     722             : 
     723             : /**
     724             :  * Get the context buffer associated with an I/O channel.
     725             :  *
     726             :  * \param ch I/O channel.
     727             :  *
     728             :  * \return a pointer to the context buffer.
     729             :  */
     730             : static inline void *
     731       78214 : spdk_io_channel_get_ctx(struct spdk_io_channel *ch)
     732             : {
     733       78214 :         if (spdk_unlikely(!ch)) {
     734           0 :                 assert(false);
     735             :                 return NULL;
     736             :         }
     737             : 
     738       78214 :         return (uint8_t *)ch + SPDK_IO_CHANNEL_STRUCT_SIZE;
     739             : }
     740             : 
     741             : /**
     742             :  * Get I/O channel from the context buffer. This is the inverse of
     743             :  * spdk_io_channel_get_ctx().
     744             :  *
     745             :  * \param ctx The pointer to the context buffer.
     746             :  *
     747             :  * \return a pointer to the I/O channel associated with the context buffer.
     748             :  */
     749             : struct spdk_io_channel *spdk_io_channel_from_ctx(void *ctx);
     750             : 
     751             : /**
     752             :  * Get the thread associated with an I/O channel.
     753             :  *
     754             :  * \param ch I/O channel.
     755             :  *
     756             :  * \return a pointer to the thread associated with the I/O channel
     757             :  */
     758             : struct spdk_thread *spdk_io_channel_get_thread(struct spdk_io_channel *ch);
     759             : 
     760             : /**
     761             :  * Call 'fn' on each channel associated with io_device.
     762             :  *
     763             :  * This happens asynchronously, so fn may be called after spdk_for_each_channel
     764             :  * returns. 'fn' will be called for each channel serially, such that two calls
     765             :  * to 'fn' will not overlap in time. After 'fn' has been called, call
     766             :  * spdk_for_each_channel_continue() to continue iterating.
     767             :  *
     768             :  * \param io_device 'fn' will be called on each channel associated with this io_device.
     769             :  * \param fn Called on the appropriate thread for each channel associated with io_device.
     770             :  * \param ctx Context buffer registered to spdk_io_channel_iter that can be obtained
     771             :  * form the function spdk_io_channel_iter_get_ctx().
     772             :  * \param cpl Called on the thread that spdk_for_each_channel was initially called
     773             :  * from when 'fn' has been called on each channel.
     774             :  */
     775             : void spdk_for_each_channel(void *io_device, spdk_channel_msg fn, void *ctx,
     776             :                            spdk_channel_for_each_cpl cpl);
     777             : 
     778             : /**
     779             :  * Get io_device from the I/O channel iterator.
     780             :  *
     781             :  * \param i I/O channel iterator.
     782             :  *
     783             :  * \return a pointer to the io_device.
     784             :  */
     785             : void *spdk_io_channel_iter_get_io_device(struct spdk_io_channel_iter *i);
     786             : 
     787             : /**
     788             :  * Get I/O channel from the I/O channel iterator.
     789             :  *
     790             :  * \param i I/O channel iterator.
     791             :  *
     792             :  * \return a pointer to the I/O channel.
     793             :  */
     794             : struct spdk_io_channel *spdk_io_channel_iter_get_channel(struct spdk_io_channel_iter *i);
     795             : 
     796             : /**
     797             :  * Get context buffer from the I/O channel iterator.
     798             :  *
     799             :  * \param i I/O channel iterator.
     800             :  *
     801             :  * \return a pointer to the context buffer.
     802             :  */
     803             : void *spdk_io_channel_iter_get_ctx(struct spdk_io_channel_iter *i);
     804             : 
     805             : /**
     806             :  * Get the io_device for the specified I/O channel.
     807             :  *
     808             :  * \param ch I/O channel.
     809             :  *
     810             :  * \return a pointer to the io_device for the I/O channel
     811             :  */
     812             : void *spdk_io_channel_get_io_device(struct spdk_io_channel *ch);
     813             : 
     814             : /**
     815             :  * Helper function to iterate all channels for spdk_for_each_channel().
     816             :  *
     817             :  * \param i I/O channel iterator.
     818             :  * \param status Status for the I/O channel iterator;
     819             :  * for non 0 status remaining iterations are terminated.
     820             :  */
     821             : void spdk_for_each_channel_continue(struct spdk_io_channel_iter *i, int status);
     822             : 
     823             : /**
     824             :  * A representative for registered interrupt file descriptor.
     825             :  */
     826             : struct spdk_interrupt;
     827             : 
     828             : /**
     829             :  * Callback function registered for interrupt file descriptor.
     830             :  *
     831             :  * \param ctx Context passed as arg to spdk_interrupt_register().
     832             :  *
     833             :  * \return 0 to indicate that interrupt took place but no events were found;
     834             :  * positive to indicate that interrupt took place and some events were processed;
     835             :  * negative if no event information is provided.
     836             :  */
     837             : typedef int (*spdk_interrupt_fn)(void *ctx);
     838             : 
     839             : /**
     840             :  * Register an spdk_interrupt on the current thread.
     841             :  *
     842             :  * The provided function will be called any time a SPDK_INTERRUPT_EVENT_IN event
     843             :  * triggers on the associated file descriptor.
     844             :  *
     845             :  * \param efd File descriptor of the spdk_interrupt.
     846             :  * \param fn Called each time there are events in spdk_interrupt.
     847             :  * \param arg Function argument for fn.
     848             :  * \param name Human readable name for the spdk_interrupt. Pointer of the spdk_interrupt
     849             :  * name is set if NULL.
     850             :  *
     851             :  * \return a pointer to the spdk_interrupt registered on the current thread on success
     852             :  * or NULL on failure.
     853             :  */
     854             : struct spdk_interrupt *spdk_interrupt_register(int efd, spdk_interrupt_fn fn,
     855             :                 void *arg, const char *name);
     856             : 
     857             : /**
     858             :  * Register an spdk_interrupt with specific event types on the current thread.
     859             :  *
     860             :  * The provided function will be called any time one of specified event types triggers on
     861             :  * the associated file descriptor.
     862             :  * Event types argument is a bit mask composed by ORing together
     863             :  * enum spdk_interrupt_event_types values.
     864             :  *
     865             :  * \param efd File descriptor of the spdk_interrupt.
     866             :  * \param events Event notification types.
     867             :  * \param fn Called each time there are events in spdk_interrupt.
     868             :  * \param arg Function argument for fn.
     869             :  * \param name Human readable name for the spdk_interrupt. Pointer of the spdk_interrupt
     870             :  * name is set if NULL.
     871             :  *
     872             :  * \return a pointer to the spdk_interrupt registered on the current thread on success
     873             :  * or NULL on failure.
     874             :  */
     875             : struct spdk_interrupt *spdk_interrupt_register_for_events(int efd, uint32_t events,
     876             :                 spdk_interrupt_fn fn, void *arg, const char *name);
     877             : 
     878             : /*
     879             :  * \brief Register an spdk_interrupt on the current thread with setting its name
     880             :  * to the string of the spdk_interrupt function name.
     881             :  */
     882             : #define SPDK_INTERRUPT_REGISTER(efd, fn, arg)   \
     883             :         spdk_interrupt_register(efd, fn, arg, #fn)
     884             : 
     885             : /*
     886             :  * \brief Register an spdk_interrupt on the current thread with specific event types
     887             :  * and with setting its name to the string of the spdk_interrupt function name.
     888             :  */
     889             : #define SPDK_INTERRUPT_REGISTER_FOR_EVENTS(efd, events, fn, arg)        \
     890             :         spdk_interrupt_register_for_events(efd, events, fn, arg, #fn)
     891             : 
     892             : /**
     893             :  * Unregister an spdk_interrupt on the current thread.
     894             :  *
     895             :  * \param pintr The spdk_interrupt to unregister.
     896             :  */
     897             : void spdk_interrupt_unregister(struct spdk_interrupt **pintr);
     898             : 
     899             : enum spdk_interrupt_event_types {
     900             : #ifdef __linux__
     901             :         SPDK_INTERRUPT_EVENT_IN = EPOLLIN,
     902             :         SPDK_INTERRUPT_EVENT_OUT = EPOLLOUT,
     903             :         SPDK_INTERRUPT_EVENT_ET = EPOLLET
     904             : #else
     905             :         SPDK_INTERRUPT_EVENT_IN =  0x001,
     906             :         SPDK_INTERRUPT_EVENT_OUT = 0x004,
     907             :         SPDK_INTERRUPT_EVENT_ET = 1u << 31
     908             : #endif
     909             : };
     910             : 
     911             : /**
     912             :  * Change the event_types associated with the spdk_interrupt on the current thread.
     913             :  *
     914             :  * \param intr The pointer to the spdk_interrupt registered on the current thread.
     915             :  * \param event_types New event_types for the spdk_interrupt.
     916             :  *
     917             :  * \return 0 if success or -errno if failed.
     918             :  */
     919             : int spdk_interrupt_set_event_types(struct spdk_interrupt *intr,
     920             :                                    enum spdk_interrupt_event_types event_types);
     921             : 
     922             : /**
     923             :  * Return a file descriptor that becomes ready whenever any of the registered
     924             :  * interrupt file descriptors are ready
     925             :  *
     926             :  * \param thread The thread to get.
     927             :  *
     928             :  * \return The spdk_interrupt fd of thread itself.
     929             :  */
     930             : int spdk_thread_get_interrupt_fd(struct spdk_thread *thread);
     931             : 
     932             : /**
     933             :  * Return an fd_group that becomes ready whenever any of the registered
     934             :  * interrupt file descriptors are ready
     935             :  *
     936             :  *
     937             :  * \param thread The thread to get.
     938             :  *
     939             :  * \return The spdk_fd_group of the thread itself.
     940             :  */
     941             : struct spdk_fd_group *spdk_thread_get_interrupt_fd_group(struct spdk_thread *thread);
     942             : 
     943             : /**
     944             :  * Set SPDK run as event driven mode
     945             :  *
     946             :  * \return 0 on success or -errno on failure
     947             :  */
     948             : int spdk_interrupt_mode_enable(void);
     949             : 
     950             : /**
     951             :  * Reports whether interrupt mode is set.
     952             :  *
     953             :  * \return True if interrupt mode is set, false otherwise.
     954             :  */
     955             : bool spdk_interrupt_mode_is_enabled(void);
     956             : 
     957             : /**
     958             :  * A spinlock augmented with safety checks for use with SPDK.
     959             :  *
     960             :  * SPDK code that uses spdk_spinlock runs from an SPDK thread, which itself is associated with a
     961             :  * pthread. There are typically many SPDK threads associated with each pthread. The SPDK application
     962             :  * may migrate SPDK threads between pthreads from time to time to balance the load on those threads.
     963             :  * Migration of SPDK threads only happens when the thread is off CPU, and as such it is only safe to
     964             :  * hold a lock so long as an SPDK thread stays on CPU.
     965             :  *
     966             :  * It is not safe to lock a spinlock, return from the event or poller, then unlock it at some later
     967             :  * time because:
     968             :  *
     969             :  *   - Even though the SPDK thread may be the same, the SPDK thread may be running on different
     970             :  *     pthreads during lock and unlock. A pthread spinlock may consider this to be an unlock by a
     971             :  *     non-owner, which results in undefined behavior.
     972             :  *   - A lock that is acquired by a poller or event may be needed by another poller or event that
     973             :  *     runs on the same pthread. This can lead to deadlock or detection of deadlock.
     974             :  *   - A lock that is acquired by a poller or event that is needed by another poller or event that
     975             :  *     runs on a second pthread will block the second pthread from doing any useful work until the
     976             :  *     lock is released. Because the lock holder and the lock acquirer are on the same pthread, this
     977             :  *     would lead to deadlock.
     978             :  *
     979             :  * If an SPDK spinlock is used erroneously, the program will abort.
     980             :  */
     981             : struct spdk_spinlock {
     982             :         pthread_spinlock_t spinlock;
     983             :         struct spdk_thread *thread;
     984             :         struct spdk_spinlock_internal *internal;
     985             :         bool initialized;
     986             :         bool destroyed;
     987             : };
     988             : 
     989             : /**
     990             :  * Initialize an spdk_spinlock.
     991             :  *
     992             :  * \param sspin The SPDK spinlock to initialize.
     993             :  */
     994             : void spdk_spin_init(struct spdk_spinlock *sspin);
     995             : 
     996             : /**
     997             :  * Destroy an spdk_spinlock.
     998             :  *
     999             :  * \param sspin The SPDK spinlock to initialize.
    1000             :  */
    1001             : void spdk_spin_destroy(struct spdk_spinlock *sspin);
    1002             : 
    1003             : /**
    1004             :  * Lock an SPDK spin lock.
    1005             :  *
    1006             :  * \param sspin An SPDK spinlock.
    1007             :  */
    1008             : void spdk_spin_lock(struct spdk_spinlock *sspin);
    1009             : 
    1010             : /**
    1011             :  * Unlock an SPDK spinlock.
    1012             :  *
    1013             :  * \param sspin An SPDK spinlock.
    1014             :  */
    1015             : void spdk_spin_unlock(struct spdk_spinlock *sspin);
    1016             : 
    1017             : /**
    1018             :  * Determine if the caller holds this SPDK spinlock.
    1019             :  *
    1020             :  * \param sspin An SPDK spinlock.
    1021             :  * \return true if spinlock is held by this thread, else false
    1022             :  */
    1023             : bool spdk_spin_held(struct spdk_spinlock *sspin);
    1024             : 
    1025             : struct spdk_iobuf_opts {
    1026             :         /** Maximum number of small buffers */
    1027             :         uint64_t small_pool_count;
    1028             :         /** Maximum number of large buffers */
    1029             :         uint64_t large_pool_count;
    1030             :         /** Size of a single small buffer */
    1031             :         uint32_t small_bufsize;
    1032             :         /** Size of a single large buffer */
    1033             :         uint32_t large_bufsize;
    1034             : 
    1035             :         /**
    1036             :          * The size of spdk_iobuf_opts according to the caller of this library is used for ABI
    1037             :          * compatibility.  The library uses this field to know how many fields in this
    1038             :          * structure are valid. And the library will populate any remaining fields with default values.
    1039             :          * New added fields should be put at the end of the struct.
    1040             :          */
    1041             :         size_t opts_size;
    1042             : 
    1043             : };
    1044             : 
    1045             : struct spdk_iobuf_pool_stats {
    1046             :         /** Buffer got from local per-thread cache */
    1047             :         uint64_t        cache;
    1048             :         /** Buffer got from the main shared pool */
    1049             :         uint64_t        main;
    1050             :         /** Buffer missed and request to get buffer was queued */
    1051             :         uint64_t        retry;
    1052             : };
    1053             : 
    1054             : struct spdk_iobuf_module_stats {
    1055             :         struct spdk_iobuf_pool_stats    small_pool;
    1056             :         struct spdk_iobuf_pool_stats    large_pool;
    1057             :         const char                      *module;
    1058             : };
    1059             : 
    1060             : struct spdk_iobuf_entry;
    1061             : 
    1062             : typedef void (*spdk_iobuf_get_cb)(struct spdk_iobuf_entry *entry, void *buf);
    1063             : 
    1064             : /** iobuf queue entry */
    1065             : struct spdk_iobuf_entry {
    1066             :         spdk_iobuf_get_cb               cb_fn;
    1067             :         const void                      *module;
    1068             :         STAILQ_ENTRY(spdk_iobuf_entry)  stailq;
    1069             : };
    1070             : 
    1071             : struct spdk_iobuf_buffer {
    1072             :         STAILQ_ENTRY(spdk_iobuf_buffer) stailq;
    1073             : };
    1074             : 
    1075             : typedef STAILQ_HEAD(, spdk_iobuf_entry) spdk_iobuf_entry_stailq_t;
    1076             : typedef STAILQ_HEAD(, spdk_iobuf_buffer) spdk_iobuf_buffer_stailq_t;
    1077             : 
    1078             : struct spdk_iobuf_pool {
    1079             :         /** Buffer pool */
    1080             :         struct spdk_ring                *pool;
    1081             :         /** Buffer cache */
    1082             :         spdk_iobuf_buffer_stailq_t      cache;
    1083             :         /** Number of elements in the cache */
    1084             :         uint32_t                        cache_count;
    1085             :         /** Size of the cache */
    1086             :         uint32_t                        cache_size;
    1087             :         /** Buffer wait queue */
    1088             :         spdk_iobuf_entry_stailq_t       *queue;
    1089             :         /** Buffer size */
    1090             :         uint32_t                        bufsize;
    1091             :         /** Pool usage statistics */
    1092             :         struct spdk_iobuf_pool_stats    stats;
    1093             : };
    1094             : 
    1095             : /** iobuf channel */
    1096             : struct spdk_iobuf_channel {
    1097             :         /** Small buffer memory pool */
    1098             :         struct spdk_iobuf_pool          small;
    1099             :         /** Large buffer memory pool */
    1100             :         struct spdk_iobuf_pool          large;
    1101             :         /** Module pointer */
    1102             :         const void                      *module;
    1103             :         /** Parent IO channel */
    1104             :         struct spdk_io_channel          *parent;
    1105             : };
    1106             : 
    1107             : /**
    1108             :  * Initialize and allocate iobuf pools.
    1109             :  *
    1110             :  * \return 0 on success, negative errno otherwise.
    1111             :  */
    1112             : int spdk_iobuf_initialize(void);
    1113             : 
    1114             : typedef void (*spdk_iobuf_finish_cb)(void *cb_arg);
    1115             : 
    1116             : /**
    1117             :  * Clean up and free iobuf pools.
    1118             :  *
    1119             :  * \param cb_fn Callback to be executed once the clean up is completed.
    1120             :  * \param cb_arg Callback argument.
    1121             :  */
    1122             : void spdk_iobuf_finish(spdk_iobuf_finish_cb cb_fn, void *cb_arg);
    1123             : 
    1124             : /**
    1125             :  * Set iobuf options.  These options will be used during `spdk_iobuf_initialize()`.
    1126             :  *
    1127             :  * \param opts Options describing the size of the pools to reserve.
    1128             :  *
    1129             :  * \return 0 on success, negative errno otherwise.
    1130             :  */
    1131             : int spdk_iobuf_set_opts(const struct spdk_iobuf_opts *opts);
    1132             : 
    1133             : /**
    1134             :  * Get iobuf options.
    1135             :  *
    1136             :  * \param opts Output parameter for options.
    1137             :  * \param opts_size sizeof(*opts)
    1138             :  */
    1139             : void spdk_iobuf_get_opts(struct spdk_iobuf_opts *opts, size_t opts_size);
    1140             : 
    1141             : /**
    1142             :  * Register a module as an iobuf pool user.  Only registered users can request buffers from the
    1143             :  * iobuf pool.
    1144             :  *
    1145             :  * \name Name of the module.
    1146             :  *
    1147             :  * \return 0 on success, negative errno otherwise.
    1148             :  */
    1149             : int spdk_iobuf_register_module(const char *name);
    1150             : 
    1151             : /**
    1152             :  * Unregister an iobuf pool user from a module.
    1153             :  *
    1154             :  * \name Name of the module.
    1155             :  *
    1156             :  * \return 0 on success, negative errno otherwise.
    1157             :  */
    1158             : int spdk_iobuf_unregister_module(const char *name);
    1159             : 
    1160             : /**
    1161             :  * Initialize an iobuf channel.
    1162             :  *
    1163             :  * \param ch iobuf channel to initialize.
    1164             :  * \param name Name of the module registered via `spdk_iobuf_register_module()`.
    1165             :  * \param small_cache_size Number of small buffers to be cached by this channel.
    1166             :  * \param large_cache_size Number of large buffers to be cached by this channel.
    1167             :  *
    1168             :  * \return 0 on success, negative errno otherwise.
    1169             :  */
    1170             : int spdk_iobuf_channel_init(struct spdk_iobuf_channel *ch, const char *name,
    1171             :                             uint32_t small_cache_size, uint32_t large_cache_size);
    1172             : 
    1173             : /**
    1174             :  * Release resources tied to an iobuf channel.
    1175             :  *
    1176             :  * \param ch iobuf channel.
    1177             :  */
    1178             : void spdk_iobuf_channel_fini(struct spdk_iobuf_channel *ch);
    1179             : 
    1180             : typedef int (*spdk_iobuf_for_each_entry_fn)(struct spdk_iobuf_channel *ch,
    1181             :                 struct spdk_iobuf_entry *entry, void *ctx);
    1182             : 
    1183             : /**
    1184             :  * Iterate over all entries on a given queue and execute a callback on those that were requested
    1185             :  * using `ch`.  The iteration is stopped if the callback returns non-zero status.
    1186             :  *
    1187             :  * \param ch iobuf channel to iterate over.
    1188             :  * \param pool Pool to iterate over (`small` or `large`).
    1189             :  * \param cb_fn Callback to execute on each entry on the queue that was requested using `ch`.
    1190             :  * \param cb_ctx Argument passed to `cb_fn`.
    1191             :  *
    1192             :  * \return status of the last callback.
    1193             :  */
    1194             : int spdk_iobuf_for_each_entry(struct spdk_iobuf_channel *ch, struct spdk_iobuf_pool *pool,
    1195             :                               spdk_iobuf_for_each_entry_fn cb_fn, void *cb_ctx);
    1196             : 
    1197             : /**
    1198             :  * Abort an outstanding request waiting for a buffer.
    1199             :  *
    1200             :  * \param ch iobuf channel on which the entry is waiting.
    1201             :  * \param entry Entry to remove from the wait queue.
    1202             :  * \param len Length of the requested buffer (must be the exact same value as specified in
    1203             :  *            `spdk_iobuf_get()`.
    1204             :  */
    1205             : void spdk_iobuf_entry_abort(struct spdk_iobuf_channel *ch, struct spdk_iobuf_entry *entry,
    1206             :                             uint64_t len);
    1207             : 
    1208             : /**
    1209             :  * Get a buffer from the iobuf pool. If no buffers are available and entry with cb_fn provided
    1210             :  * then the request is queued until a buffer becomes available.
    1211             :  *
    1212             :  * \param ch iobuf channel.
    1213             :  * \param len Length of the buffer to retrieve. The user is responsible for making sure the length
    1214             :  *            doesn't exceed large_bufsize.
    1215             :  * \param entry Wait queue entry (optional).
    1216             :  * \param cb_fn Callback to be executed once a buffer becomes available. If a buffer is available
    1217             :  *              immediately, it is NOT executed. Mandatory only if entry provided.
    1218             :  *
    1219             :  * \return pointer to a buffer or NULL if no buffers are currently available.
    1220             :  */
    1221             : void *spdk_iobuf_get(struct spdk_iobuf_channel *ch, uint64_t len, struct spdk_iobuf_entry *entry,
    1222             :                      spdk_iobuf_get_cb cb_fn);
    1223             : 
    1224             : /**
    1225             :  * Release a buffer back to the iobuf pool.  If there are outstanding requests waiting for a buffer,
    1226             :  * this buffer will be passed to one of them.
    1227             :  *
    1228             :  * \param ch iobuf channel.
    1229             :  * \param buf Buffer to release
    1230             :  * \param len Length of the buffer (must be the exact same value as specified in `spdk_iobuf_get()`).
    1231             :  */
    1232             : void spdk_iobuf_put(struct spdk_iobuf_channel *ch, void *buf, uint64_t len);
    1233             : 
    1234             : typedef void (*spdk_iobuf_get_stats_cb)(struct spdk_iobuf_module_stats *modules,
    1235             :                                         uint32_t num_modules, void *cb_arg);
    1236             : 
    1237             : /**
    1238             :  * Get iobuf statistics.
    1239             :  *
    1240             :  * \param cb_fn Callback to be executed once stats are gathered.
    1241             :  * \param cb_arg Argument passed to the callback function.
    1242             :  *
    1243             :  * \return 0 on success, negative errno otherwise.
    1244             :  */
    1245             : int spdk_iobuf_get_stats(spdk_iobuf_get_stats_cb cb_fn, void *cb_arg);
    1246             : 
    1247             : #ifdef __cplusplus
    1248             : }
    1249             : #endif
    1250             : 
    1251             : #endif /* SPDK_THREAD_H_ */

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