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: 2024-07-15 12:31:32 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 implementor 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 implementor 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             :  * \param poller The poller to register callback function.
     128             :  * \param cb_fn Callback function called when the poller must transition into or out of interrupt mode
     129             :  * \param cb_arg Argument passed to the callback function.
     130             :  */
     131             : void spdk_poller_register_interrupt(struct spdk_poller *poller,
     132             :                                     spdk_poller_set_interrupt_mode_cb cb_fn,
     133             :                                     void *cb_arg);
     134             : 
     135             : /**
     136             :  * I/O channel creation callback.
     137             :  *
     138             :  * \param io_device I/O device associated with this channel.
     139             :  * \param ctx_buf Context for the I/O device.
     140             :  */
     141             : typedef int (*spdk_io_channel_create_cb)(void *io_device, void *ctx_buf);
     142             : 
     143             : /**
     144             :  * I/O channel destruction callback.
     145             :  *
     146             :  * \param io_device I/O device associated with this channel.
     147             :  * \param ctx_buf Context for the I/O device.
     148             :  */
     149             : typedef void (*spdk_io_channel_destroy_cb)(void *io_device, void *ctx_buf);
     150             : 
     151             : /**
     152             :  * I/O device unregister callback.
     153             :  *
     154             :  * \param io_device Unregistered I/O device.
     155             :  */
     156             : typedef void (*spdk_io_device_unregister_cb)(void *io_device);
     157             : 
     158             : /**
     159             :  * Called on the appropriate thread for each channel associated with io_device.
     160             :  *
     161             :  * \param i I/O channel iterator.
     162             :  */
     163             : typedef void (*spdk_channel_msg)(struct spdk_io_channel_iter *i);
     164             : 
     165             : /**
     166             :  * spdk_for_each_channel() callback.
     167             :  *
     168             :  * \param i I/O channel iterator.
     169             :  * \param status 0 if it completed successfully, or negative errno if it failed.
     170             :  */
     171             : typedef void (*spdk_channel_for_each_cpl)(struct spdk_io_channel_iter *i, int status);
     172             : 
     173             : #define SPDK_IO_CHANNEL_STRUCT_SIZE     96
     174             : 
     175             : /**
     176             :  * Message memory pool size definitions
     177             :  */
     178             : #define SPDK_MSG_MEMPOOL_CACHE_SIZE     1024
     179             : /* Power of 2 minus 1 is optimal for memory consumption */
     180             : #define SPDK_DEFAULT_MSG_MEMPOOL_SIZE (262144 - 1)
     181             : 
     182             : /**
     183             :  * Initialize the threading library. Must be called once prior to allocating any threads.
     184             :  *
     185             :  * \param new_thread_fn Called each time a new SPDK thread is created. The implementor
     186             :  * is expected to frequently call spdk_thread_poll() on the provided thread.
     187             :  * \param ctx_sz For each thread allocated, an additional region of memory of
     188             :  * size ctx_size will also be allocated, for use by the thread scheduler. A pointer
     189             :  * to this region may be obtained by calling spdk_thread_get_ctx().
     190             :  *
     191             :  * \return 0 on success. Negated errno on failure.
     192             :  */
     193             : int spdk_thread_lib_init(spdk_new_thread_fn new_thread_fn, size_t ctx_sz);
     194             : 
     195             : /**
     196             :  * Initialize the threading library. Must be called once prior to allocating any threads
     197             :  *
     198             :  * Both thread_op_fn and thread_op_type_supported_fn have to be specified or not
     199             :  * specified together.
     200             :  *
     201             :  * \param thread_op_fn Called for SPDK thread operation.
     202             :  * \param thread_op_supported_fn Called to check whether the SPDK thread operation is supported.
     203             :  * \param ctx_sz For each thread allocated, for use by the thread scheduler. A pointer
     204             :  * to this region may be obtained by calling spdk_thread_get_ctx().
     205             :  * \param msg_mempool_size Size of the allocated spdk_msg_mempool.
     206             :  *
     207             :  * \return 0 on success. Negated errno on failure.
     208             :  */
     209             : int spdk_thread_lib_init_ext(spdk_thread_op_fn thread_op_fn,
     210             :                              spdk_thread_op_supported_fn thread_op_supported_fn,
     211             :                              size_t ctx_sz, size_t msg_mempool_size);
     212             : 
     213             : /**
     214             :  * Release all resources associated with this library.
     215             :  */
     216             : void spdk_thread_lib_fini(void);
     217             : 
     218             : /**
     219             :  * Creates a new SPDK thread object.
     220             :  *
     221             :  * Note that the first thread created via spdk_thread_create() will be designated as
     222             :  * the app thread.  Other SPDK libraries may place restrictions on certain APIs to
     223             :  * only be called in the context of this app thread.
     224             :  *
     225             :  * \param name Human-readable name for the thread; can be retrieved with spdk_thread_get_name().
     226             :  * The string is copied, so the pointed-to data only needs to be valid during the
     227             :  * spdk_thread_create() call. May be NULL to specify no name.
     228             :  * \param cpumask Optional mask of CPU cores on which to schedule this thread. This is only
     229             :  * a suggestion to the scheduler. The value is copied, so cpumask may be released when
     230             :  * this function returns. May be NULL if no mask is required.
     231             :  *
     232             :  * \return a pointer to the allocated thread on success or NULL on failure..
     233             :  */
     234             : struct spdk_thread *spdk_thread_create(const char *name, const struct spdk_cpuset *cpumask);
     235             : 
     236             : /**
     237             :  * Return the app thread.
     238             :  *
     239             :  * The app thread is the first thread created using spdk_thread_create().
     240             :  *
     241             :  * \return a pointer to the app thread, or NULL if no thread has been created yet.
     242             :  */
     243             : struct spdk_thread *spdk_thread_get_app_thread(void);
     244             : 
     245             : /**
     246             :  * Check if the specified spdk_thread is the app thread.
     247             :  *
     248             :  * \param thread The thread to check. If NULL, check the current spdk_thread.
     249             :  * \return true if the specified spdk_thread is the app thread, false otherwise.
     250             :  */
     251             : bool spdk_thread_is_app_thread(struct spdk_thread *thread);
     252             : 
     253             : /**
     254             :  * Force the current system thread to act as if executing the given SPDK thread.
     255             :  *
     256             :  * \param thread The thread to set.
     257             :  */
     258             : void spdk_set_thread(struct spdk_thread *thread);
     259             : 
     260             : /**
     261             :  * Bind or unbind spdk_thread to its current CPU core.
     262             :  *
     263             :  * If spdk_thread is bound, it couldn't be rescheduled to other CPU cores until it is unbound.
     264             :  *
     265             :  * \param thread The thread to bind or not.
     266             :  * \param bind true for bind, false for unbind.
     267             :  */
     268             : void spdk_thread_bind(struct spdk_thread *thread, bool bind);
     269             : 
     270             : /**
     271             :  * Returns whether the thread is bound to its current CPU core.
     272             :  *
     273             :  * \param thread The thread to query.
     274             :  *
     275             :  * \return true if bound, false otherwise
     276             :  */
     277             : bool spdk_thread_is_bound(struct spdk_thread *thread);
     278             : 
     279             : /**
     280             :  * Mark the thread as exited, failing all future spdk_thread_send_msg(),
     281             :  * spdk_poller_register(), and spdk_get_io_channel() calls. May only be called
     282             :  * within an spdk poller or message.
     283             :  *
     284             :  * All I/O channel references associated with the thread must be released
     285             :  * using spdk_put_io_channel(), and all active pollers associated with the thread
     286             :  * should be unregistered using spdk_poller_unregister(), prior to calling
     287             :  * this function. This function will complete these processing. The completion can
     288             :  * be queried by spdk_thread_is_exited().
     289             :  *
     290             :  * Note that this function must not be called on the app thread until after it
     291             :  * has been called for all other threads.
     292             :  *
     293             :  * \param thread The thread to exit.
     294             :  *
     295             :  * \return always 0. (return value was deprecated but keep it for ABI compatibility.)
     296             :  */
     297             : int spdk_thread_exit(struct spdk_thread *thread);
     298             : 
     299             : /**
     300             :  * Returns whether the thread is marked as exited.
     301             :  *
     302             :  * A thread is exited only after it has spdk_thread_exit() called on it, and
     303             :  * it has been polled until any outstanding operations targeting this
     304             :  * thread have completed.  This may include poller unregistrations, io channel
     305             :  * unregistrations, or outstanding spdk_thread_send_msg calls.
     306             :  *
     307             :  * \param thread The thread to query.
     308             :  *
     309             :  * \return true if marked as exited, false otherwise.
     310             :  */
     311             : bool spdk_thread_is_exited(struct spdk_thread *thread);
     312             : 
     313             : /**
     314             :  * Returns whether the thread is still running.
     315             :  *
     316             :  * A thread is considered running until it has * spdk_thread_exit() called on it.
     317             :  *
     318             :  * \param thread The thread to query.
     319             :  *
     320             :  * \return true if still running, false otherwise.
     321             :  */
     322             : bool spdk_thread_is_running(struct spdk_thread *thread);
     323             : 
     324             : /**
     325             :  * Destroy a thread, releasing all of its resources. May only be called
     326             :  * on a thread previously marked as exited.
     327             :  *
     328             :  * \param thread The thread to destroy.
     329             :  *
     330             :  */
     331             : void spdk_thread_destroy(struct spdk_thread *thread);
     332             : 
     333             : /**
     334             :  * Return a pointer to this thread's context.
     335             :  *
     336             :  * \param thread The thread on which to get the context.
     337             :  *
     338             :  * \return a pointer to the per-thread context, or NULL if there is
     339             :  * no per-thread context.
     340             :  */
     341             : void *spdk_thread_get_ctx(struct spdk_thread *thread);
     342             : 
     343             : /**
     344             :  * Get the thread's cpumask.
     345             :  *
     346             :  * \param thread The thread to get the cpumask for.
     347             :  *
     348             :  * \return cpuset pointer
     349             :  */
     350             : struct spdk_cpuset *spdk_thread_get_cpumask(struct spdk_thread *thread);
     351             : 
     352             : /**
     353             :  * Set the current thread's cpumask to the specified value. The thread may be
     354             :  * rescheduled to one of the CPUs specified in the cpumask.
     355             :  *
     356             :  * This API requires SPDK thread operation supports SPDK_THREAD_OP_RESCHED.
     357             :  *
     358             :  * \param cpumask The new cpumask for the thread.
     359             :  *
     360             :  * \return 0 on success, negated errno otherwise.
     361             :  */
     362             : int spdk_thread_set_cpumask(struct spdk_cpuset *cpumask);
     363             : 
     364             : /**
     365             :  * Return the thread object associated with the context handle previously
     366             :  * obtained by calling spdk_thread_get_ctx().
     367             :  *
     368             :  * \param ctx A context previously obtained by calling spdk_thread_get_ctx()
     369             :  *
     370             :  * \return The associated thread.
     371             :  */
     372             : struct spdk_thread *spdk_thread_get_from_ctx(void *ctx);
     373             : 
     374             : /**
     375             :  * Perform one iteration worth of processing on the thread. This includes
     376             :  * both expired and continuous pollers as well as messages. If the thread
     377             :  * has exited, return immediately.
     378             :  *
     379             :  * \param thread The thread to process
     380             :  * \param max_msgs The maximum number of messages that will be processed.
     381             :  *                 Use 0 to process the default number of messages (8).
     382             :  * \param now The current time, in ticks. Optional. If 0 is passed, this
     383             :  *            function will call spdk_get_ticks() to get the current time.
     384             :  *            The current time is used as start time and this function
     385             :  *            will call spdk_get_ticks() at its end to know end time to
     386             :  *            measure run time of this function.
     387             :  *
     388             :  * \return 1 if work was done. 0 if no work was done.
     389             :  */
     390             : int spdk_thread_poll(struct spdk_thread *thread, uint32_t max_msgs, uint64_t now);
     391             : 
     392             : /**
     393             :  * Return the number of ticks until the next timed poller
     394             :  * would expire. Timed pollers are pollers for which
     395             :  * period_microseconds is greater than 0.
     396             :  *
     397             :  * \param thread The thread to check poller expiration times on
     398             :  *
     399             :  * \return Number of ticks. If no timed pollers, return 0.
     400             :  */
     401             : uint64_t spdk_thread_next_poller_expiration(struct spdk_thread *thread);
     402             : 
     403             : /**
     404             :  * Returns whether there are any active pollers (pollers for which
     405             :  * period_microseconds equals 0) registered to be run on the thread.
     406             :  *
     407             :  * \param thread The thread to check.
     408             :  *
     409             :  * \return 1 if there is at least one active poller, 0 otherwise.
     410             :  */
     411             : int spdk_thread_has_active_pollers(struct spdk_thread *thread);
     412             : 
     413             : /**
     414             :  * Returns whether there are any pollers registered to be run
     415             :  * on the thread.
     416             :  *
     417             :  * \param thread The thread to check.
     418             :  *
     419             :  * \return true if there is any active poller, false otherwise.
     420             :  */
     421             : bool spdk_thread_has_pollers(struct spdk_thread *thread);
     422             : 
     423             : /**
     424             :  * Returns whether there are scheduled operations to be run on the thread.
     425             :  *
     426             :  * \param thread The thread to check.
     427             :  *
     428             :  * \return true if there are no scheduled operations, false otherwise.
     429             :  */
     430             : bool spdk_thread_is_idle(struct spdk_thread *thread);
     431             : 
     432             : /**
     433             :  * Get count of allocated threads.
     434             :  */
     435             : uint32_t spdk_thread_get_count(void);
     436             : 
     437             : /**
     438             :  * Get a handle to the current thread.
     439             :  *
     440             :  * This handle may be passed to other threads and used as the target of
     441             :  * spdk_thread_send_msg().
     442             :  *
     443             :  * \sa spdk_io_channel_get_thread()
     444             :  *
     445             :  * \return a pointer to the current thread on success or NULL on failure.
     446             :  */
     447             : struct spdk_thread *spdk_get_thread(void);
     448             : 
     449             : /**
     450             :  * Get a thread's name.
     451             :  *
     452             :  * \param thread Thread to query.
     453             :  *
     454             :  * \return the name of the thread.
     455             :  */
     456             : const char *spdk_thread_get_name(const struct spdk_thread *thread);
     457             : 
     458             : /**
     459             :  * Get a thread's ID.
     460             :  *
     461             :  * \param thread Thread to query.
     462             :  *
     463             :  * \return the ID of the thread..
     464             :  */
     465             : uint64_t spdk_thread_get_id(const struct spdk_thread *thread);
     466             : 
     467             : /**
     468             :  * Get the thread by the ID.
     469             :  *
     470             :  * \param id ID of the thread.
     471             :  * \return Thread whose ID matches or NULL otherwise.
     472             :  */
     473             : struct spdk_thread *spdk_thread_get_by_id(uint64_t id);
     474             : 
     475             : struct spdk_thread_stats {
     476             :         uint64_t busy_tsc;
     477             :         uint64_t idle_tsc;
     478             : };
     479             : 
     480             : /**
     481             :  * Get statistics about the current thread.
     482             :  *
     483             :  * Copy cumulative thread stats values to the provided thread stats structure.
     484             :  *
     485             :  * \param stats User's thread_stats structure.
     486             :  */
     487             : int spdk_thread_get_stats(struct spdk_thread_stats *stats);
     488             : 
     489             : /**
     490             :  * Return the TSC value from the end of the last time this thread was polled.
     491             :  *
     492             :  * \param thread Thread to query.  If NULL, use current thread.
     493             :  *
     494             :  * \return TSC value from the end of the last time this thread was polled.
     495             :  */
     496             : uint64_t spdk_thread_get_last_tsc(struct spdk_thread *thread);
     497             : 
     498             : /**
     499             :  * Send a message to the given thread.
     500             :  *
     501             :  * The message will be sent asynchronously - i.e. spdk_thread_send_msg will always return
     502             :  * prior to `fn` being called.
     503             :  *
     504             :  * \param thread The target thread.
     505             :  * \param fn This function will be called on the given thread.
     506             :  * \param ctx This context will be passed to fn when called.
     507             :  *
     508             :  * \return 0 on success
     509             :  * \return -ENOMEM if the message could not be allocated
     510             :  * \return -EIO if the message could not be sent to the destination thread
     511             :  */
     512             : int spdk_thread_send_msg(const struct spdk_thread *thread, spdk_msg_fn fn, void *ctx);
     513             : 
     514             : /**
     515             :  * Send a message to the given thread. Only one critical message can be outstanding at the same
     516             :  * time. It's intended to use this function in any cases that might interrupt the execution of the
     517             :  * application, such as signal handlers.
     518             :  *
     519             :  * The message will be sent asynchronously - i.e. spdk_thread_send_critical_msg will always return
     520             :  * prior to `fn` being called.
     521             :  *
     522             :  * \param thread The target thread.
     523             :  * \param fn This function will be called on the given thread.
     524             :  *
     525             :  * \return 0 on success
     526             :  * \return -EIO if the message could not be sent to the destination thread, due to an already
     527             :  * outstanding critical message
     528             :  */
     529             : int spdk_thread_send_critical_msg(struct spdk_thread *thread, spdk_msg_fn fn);
     530             : 
     531             : /**
     532             :  * Run the msg callback on the given thread. If this happens to be the current
     533             :  * thread, the callback is executed immediately; otherwise a message is sent to
     534             :  * the thread, and it's run asynchronously.
     535             :  *
     536             :  * \param thread The target thread.
     537             :  * \param fn This function will be called on the given thread.
     538             :  * \param ctx This context will be passed to fn when called.
     539             :  *
     540             :  * \return 0 on success
     541             :  * \return -ENOMEM if the message could not be allocated
     542             :  * \return -EIO if the message could not be sent to the destination thread
     543             :  */
     544             : static inline int
     545         114 : spdk_thread_exec_msg(const struct spdk_thread *thread, spdk_msg_fn fn, void *ctx)
     546             : {
     547         114 :         assert(thread != NULL);
     548             : 
     549         114 :         if (spdk_get_thread() == thread) {
     550         112 :                 fn(ctx);
     551         112 :                 return 0;
     552             :         }
     553             : 
     554           2 :         return spdk_thread_send_msg(thread, fn, ctx);
     555             : }
     556             : 
     557             : /**
     558             :  * Send a message to each thread, serially.
     559             :  *
     560             :  * The message is sent asynchronously - i.e. spdk_for_each_thread will return
     561             :  * prior to `fn` being called on each thread.
     562             :  *
     563             :  * \param fn This is the function that will be called on each thread.
     564             :  * \param ctx This context will be passed to fn when called.
     565             :  * \param cpl This will be called on the originating thread after `fn` has been
     566             :  * called on each thread.
     567             :  */
     568             : void spdk_for_each_thread(spdk_msg_fn fn, void *ctx, spdk_msg_fn cpl);
     569             : 
     570             : /**
     571             :  * Set current spdk_thread into interrupt mode or back to poll mode.
     572             :  *
     573             :  * Only valid when thread interrupt facility is enabled by
     574             :  * spdk_interrupt_mode_enable().
     575             :  *
     576             :  * \param enable_interrupt Set interrupt mode for true, or poll mode for false
     577             :  */
     578             : void spdk_thread_set_interrupt_mode(bool enable_interrupt);
     579             : 
     580             : /**
     581             :  * Register a poller on the current thread.
     582             :  *
     583             :  * The poller can be unregistered by calling spdk_poller_unregister().
     584             :  *
     585             :  * \param fn This function will be called every `period_microseconds`.
     586             :  * \param arg Argument passed to fn.
     587             :  * \param period_microseconds How often to call `fn`. If 0, call `fn` as often
     588             :  *  as possible.
     589             :  *
     590             :  * \return a pointer to the poller registered on the current thread on success
     591             :  * or NULL on failure.
     592             :  */
     593             : struct spdk_poller *spdk_poller_register(spdk_poller_fn fn,
     594             :                 void *arg,
     595             :                 uint64_t period_microseconds);
     596             : 
     597             : /**
     598             :  * Register a poller on the current thread with arbitrary name.
     599             :  *
     600             :  * The poller can be unregistered by calling spdk_poller_unregister().
     601             :  *
     602             :  * \param fn This function will be called every `period_microseconds`.
     603             :  * \param arg Argument passed to fn.
     604             :  * \param period_microseconds How often to call `fn`. If 0, call `fn` as often
     605             :  *  as possible.
     606             :  * \param name Human readable name for the poller. Pointer of the poller function
     607             :  * name is set if NULL.
     608             :  *
     609             :  * \return a pointer to the poller registered on the current thread on success
     610             :  * or NULL on failure.
     611             :  */
     612             : struct spdk_poller *spdk_poller_register_named(spdk_poller_fn fn,
     613             :                 void *arg,
     614             :                 uint64_t period_microseconds,
     615             :                 const char *name);
     616             : 
     617             : /*
     618             :  * \brief Register a poller on the current thread with setting its name
     619             :  * to the string of the poller function name. The poller being registered
     620             :  * should return a value of type `enum spdk_thread_poller_rc`. See
     621             :  * \ref spdk_poller_fn for more information.
     622             :  */
     623             : #define SPDK_POLLER_REGISTER(fn, arg, period_microseconds)      \
     624             :         spdk_poller_register_named(fn, arg, period_microseconds, #fn)
     625             : 
     626             : /**
     627             :  * Unregister a poller on the current thread.
     628             :  *
     629             :  * \param ppoller The poller to unregister.
     630             :  */
     631             : void spdk_poller_unregister(struct spdk_poller **ppoller);
     632             : 
     633             : /**
     634             :  * Pause a poller on the current thread.
     635             :  *
     636             :  * The poller is not run until it is resumed with spdk_poller_resume().  It is
     637             :  * perfectly fine to pause an already paused poller.
     638             :  *
     639             :  * \param poller The poller to pause.
     640             :  */
     641             : void spdk_poller_pause(struct spdk_poller *poller);
     642             : 
     643             : /**
     644             :  * Resume a poller on the current thread.
     645             :  *
     646             :  * Resumes a poller paused with spdk_poller_pause().  It is perfectly fine to
     647             :  * resume an unpaused poller.
     648             :  *
     649             :  * \param poller The poller to resume.
     650             :  */
     651             : void spdk_poller_resume(struct spdk_poller *poller);
     652             : 
     653             : /**
     654             :  * Register the opaque io_device context as an I/O device.
     655             :  *
     656             :  * After an I/O device is registered, it can return I/O channels using the
     657             :  * spdk_get_io_channel() function.
     658             :  *
     659             :  * \param io_device The pointer to io_device context.
     660             :  * \param create_cb Callback function invoked to allocate any resources required
     661             :  * for a new I/O channel.
     662             :  * \param destroy_cb Callback function invoked to release the resources for an
     663             :  * I/O channel.
     664             :  * \param ctx_size The size of the context buffer allocated to store references
     665             :  * to allocated I/O channel resources.
     666             :  * \param name A string name for the device used only for debugging. Optional -
     667             :  * may be NULL.
     668             :  */
     669             : void spdk_io_device_register(void *io_device, spdk_io_channel_create_cb create_cb,
     670             :                              spdk_io_channel_destroy_cb destroy_cb, uint32_t ctx_size,
     671             :                              const char *name);
     672             : 
     673             : /**
     674             :  * Unregister the opaque io_device context as an I/O device.
     675             :  *
     676             :  * The actual unregistration might be deferred until all active I/O channels are
     677             :  * destroyed.
     678             :  *
     679             :  * \param io_device The pointer to io_device context.
     680             :  * \param unregister_cb An optional callback function invoked to release any
     681             :  * references to this I/O device.
     682             :  */
     683             : void spdk_io_device_unregister(void *io_device, spdk_io_device_unregister_cb unregister_cb);
     684             : 
     685             : /**
     686             :  * Get an I/O channel for the specified io_device to be used by the calling thread.
     687             :  *
     688             :  * The io_device context pointer specified must have previously been registered
     689             :  * using spdk_io_device_register(). If an existing I/O channel does not exist
     690             :  * yet for the given io_device on the calling thread, it will allocate an I/O
     691             :  * channel and invoke the create_cb function pointer specified in spdk_io_device_register().
     692             :  * If an I/O channel already exists for the given io_device on the calling thread,
     693             :  * its reference is returned rather than creating a new I/O channel.
     694             :  *
     695             :  * \param io_device The pointer to io_device context.
     696             :  *
     697             :  * \return a pointer to the I/O channel for this device on success or NULL on failure.
     698             :  */
     699             : struct spdk_io_channel *spdk_get_io_channel(void *io_device);
     700             : 
     701             : /**
     702             :  * Release a reference to an I/O channel. This happens asynchronously.
     703             :  *
     704             :  * This must be called on the same thread that called spdk_get_io_channel()
     705             :  * for the specified I/O channel. If this releases the last reference to the
     706             :  * I/O channel, The destroy_cb function specified in spdk_io_device_register()
     707             :  * will be invoked to release any associated resources.
     708             :  *
     709             :  * \param ch I/O channel to release a reference.
     710             :  */
     711             : void spdk_put_io_channel(struct spdk_io_channel *ch);
     712             : 
     713             : /**
     714             :  * Get the context buffer associated with an I/O channel.
     715             :  *
     716             :  * \param ch I/O channel.
     717             :  *
     718             :  * \return a pointer to the context buffer.
     719             :  */
     720             : static inline void *
     721       77755 : spdk_io_channel_get_ctx(struct spdk_io_channel *ch)
     722             : {
     723       77755 :         if (spdk_unlikely(!ch)) {
     724           0 :                 assert(false);
     725             :                 return NULL;
     726             :         }
     727             : 
     728       77755 :         return (uint8_t *)ch + SPDK_IO_CHANNEL_STRUCT_SIZE;
     729             : }
     730             : 
     731             : /**
     732             :  * Get I/O channel from the context buffer. This is the inverse of
     733             :  * spdk_io_channel_get_ctx().
     734             :  *
     735             :  * \param ctx The pointer to the context buffer.
     736             :  *
     737             :  * \return a pointer to the I/O channel associated with the context buffer.
     738             :  */
     739             : struct spdk_io_channel *spdk_io_channel_from_ctx(void *ctx);
     740             : 
     741             : /**
     742             :  * Get the thread associated with an I/O channel.
     743             :  *
     744             :  * \param ch I/O channel.
     745             :  *
     746             :  * \return a pointer to the thread associated with the I/O channel
     747             :  */
     748             : struct spdk_thread *spdk_io_channel_get_thread(struct spdk_io_channel *ch);
     749             : 
     750             : /**
     751             :  * Call 'fn' on each channel associated with io_device.
     752             :  *
     753             :  * This happens asynchronously, so fn may be called after spdk_for_each_channel
     754             :  * returns. 'fn' will be called for each channel serially, such that two calls
     755             :  * to 'fn' will not overlap in time. After 'fn' has been called, call
     756             :  * spdk_for_each_channel_continue() to continue iterating.
     757             :  *
     758             :  * \param io_device 'fn' will be called on each channel associated with this io_device.
     759             :  * \param fn Called on the appropriate thread for each channel associated with io_device.
     760             :  * \param ctx Context buffer registered to spdk_io_channel_iter that can be obtained
     761             :  * form the function spdk_io_channel_iter_get_ctx().
     762             :  * \param cpl Called on the thread that spdk_for_each_channel was initially called
     763             :  * from when 'fn' has been called on each channel.
     764             :  */
     765             : void spdk_for_each_channel(void *io_device, spdk_channel_msg fn, void *ctx,
     766             :                            spdk_channel_for_each_cpl cpl);
     767             : 
     768             : /**
     769             :  * Get io_device from the I/O channel iterator.
     770             :  *
     771             :  * \param i I/O channel iterator.
     772             :  *
     773             :  * \return a pointer to the io_device.
     774             :  */
     775             : void *spdk_io_channel_iter_get_io_device(struct spdk_io_channel_iter *i);
     776             : 
     777             : /**
     778             :  * Get I/O channel from the I/O channel iterator.
     779             :  *
     780             :  * \param i I/O channel iterator.
     781             :  *
     782             :  * \return a pointer to the I/O channel.
     783             :  */
     784             : struct spdk_io_channel *spdk_io_channel_iter_get_channel(struct spdk_io_channel_iter *i);
     785             : 
     786             : /**
     787             :  * Get context buffer from the I/O channel iterator.
     788             :  *
     789             :  * \param i I/O channel iterator.
     790             :  *
     791             :  * \return a pointer to the context buffer.
     792             :  */
     793             : void *spdk_io_channel_iter_get_ctx(struct spdk_io_channel_iter *i);
     794             : 
     795             : /**
     796             :  * Get the io_device for the specified I/O channel.
     797             :  *
     798             :  * \param ch I/O channel.
     799             :  *
     800             :  * \return a pointer to the io_device for the I/O channel
     801             :  */
     802             : void *spdk_io_channel_get_io_device(struct spdk_io_channel *ch);
     803             : 
     804             : /**
     805             :  * Helper function to iterate all channels for spdk_for_each_channel().
     806             :  *
     807             :  * \param i I/O channel iterator.
     808             :  * \param status Status for the I/O channel iterator;
     809             :  * for non 0 status remaining iterations are terminated.
     810             :  */
     811             : void spdk_for_each_channel_continue(struct spdk_io_channel_iter *i, int status);
     812             : 
     813             : /**
     814             :  * A representative for registered interrupt file descriptor.
     815             :  */
     816             : struct spdk_interrupt;
     817             : 
     818             : /**
     819             :  * Callback function registered for interrupt file descriptor.
     820             :  *
     821             :  * \param ctx Context passed as arg to spdk_interrupt_register().
     822             :  *
     823             :  * \return 0 to indicate that interrupt took place but no events were found;
     824             :  * positive to indicate that interrupt took place and some events were processed;
     825             :  * negative if no event information is provided.
     826             :  */
     827             : typedef int (*spdk_interrupt_fn)(void *ctx);
     828             : 
     829             : /**
     830             :  * Register an spdk_interrupt on the current thread.
     831             :  *
     832             :  * The provided function will be called any time a SPDK_INTERRUPT_EVENT_IN event
     833             :  * triggers on the associated file descriptor.
     834             :  *
     835             :  * \param efd File descriptor of the spdk_interrupt.
     836             :  * \param fn Called each time there are events in spdk_interrupt.
     837             :  * \param arg Function argument for fn.
     838             :  * \param name Human readable name for the spdk_interrupt. Pointer of the spdk_interrupt
     839             :  * name is set if NULL.
     840             :  *
     841             :  * \return a pointer to the spdk_interrupt registered on the current thread on success
     842             :  * or NULL on failure.
     843             :  */
     844             : struct spdk_interrupt *spdk_interrupt_register(int efd, spdk_interrupt_fn fn,
     845             :                 void *arg, const char *name);
     846             : 
     847             : /**
     848             :  * Register an spdk_interrupt with specific event types on the current thread.
     849             :  *
     850             :  * The provided function will be called any time one of specified event types triggers on
     851             :  * the associated file descriptor.
     852             :  * Event types argument is a bit mask composed by ORing together
     853             :  * enum spdk_interrupt_event_types values.
     854             :  *
     855             :  * \param efd File descriptor of the spdk_interrupt.
     856             :  * \param events Event notification types.
     857             :  * \param fn Called each time there are events in spdk_interrupt.
     858             :  * \param arg Function argument for fn.
     859             :  * \param name Human readable name for the spdk_interrupt. Pointer of the spdk_interrupt
     860             :  * name is set if NULL.
     861             :  *
     862             :  * \return a pointer to the spdk_interrupt registered on the current thread on success
     863             :  * or NULL on failure.
     864             :  */
     865             : struct spdk_interrupt *spdk_interrupt_register_for_events(int efd, uint32_t events,
     866             :                 spdk_interrupt_fn fn, void *arg, const char *name);
     867             : 
     868             : /*
     869             :  * \brief Register an spdk_interrupt on the current thread with setting its name
     870             :  * to the string of the spdk_interrupt function name.
     871             :  */
     872             : #define SPDK_INTERRUPT_REGISTER(efd, fn, arg)   \
     873             :         spdk_interrupt_register(efd, fn, arg, #fn)
     874             : 
     875             : /*
     876             :  * \brief Register an spdk_interrupt on the current thread with specific event types
     877             :  * and with setting its name to the string of the spdk_interrupt function name.
     878             :  */
     879             : #define SPDK_INTERRUPT_REGISTER_FOR_EVENTS(efd, events, fn, arg)        \
     880             :         spdk_interrupt_register_for_events(efd, events, fn, arg, #fn)
     881             : 
     882             : /**
     883             :  * Unregister an spdk_interrupt on the current thread.
     884             :  *
     885             :  * \param pintr The spdk_interrupt to unregister.
     886             :  */
     887             : void spdk_interrupt_unregister(struct spdk_interrupt **pintr);
     888             : 
     889             : enum spdk_interrupt_event_types {
     890             : #ifdef __linux__
     891             :         SPDK_INTERRUPT_EVENT_IN = EPOLLIN,
     892             :         SPDK_INTERRUPT_EVENT_OUT = EPOLLOUT,
     893             :         SPDK_INTERRUPT_EVENT_ET = EPOLLET
     894             : #else
     895             :         SPDK_INTERRUPT_EVENT_IN =  0x001,
     896             :         SPDK_INTERRUPT_EVENT_OUT = 0x004,
     897             :         SPDK_INTERRUPT_EVENT_ET = 1u << 31
     898             : #endif
     899             : };
     900             : 
     901             : /**
     902             :  * Change the event_types associated with the spdk_interrupt on the current thread.
     903             :  *
     904             :  * \param intr The pointer to the spdk_interrupt registered on the current thread.
     905             :  * \param event_types New event_types for the spdk_interrupt.
     906             :  *
     907             :  * \return 0 if success or -errno if failed.
     908             :  */
     909             : int spdk_interrupt_set_event_types(struct spdk_interrupt *intr,
     910             :                                    enum spdk_interrupt_event_types event_types);
     911             : 
     912             : /**
     913             :  * Return a file descriptor that becomes ready whenever any of the registered
     914             :  * interrupt file descriptors are ready
     915             :  *
     916             :  * \param thread The thread to get.
     917             :  *
     918             :  * \return The spdk_interrupt fd of thread itself.
     919             :  */
     920             : int spdk_thread_get_interrupt_fd(struct spdk_thread *thread);
     921             : 
     922             : /**
     923             :  * Return an fd_group that becomes ready whenever any of the registered
     924             :  * interrupt file descriptors are ready
     925             :  *
     926             :  *
     927             :  * \param thread The thread to get.
     928             :  *
     929             :  * \return The spdk_fd_group of the thread itself.
     930             :  */
     931             : struct spdk_fd_group *spdk_thread_get_interrupt_fd_group(struct spdk_thread *thread);
     932             : 
     933             : /**
     934             :  * Set SPDK run as event driven mode
     935             :  *
     936             :  * \return 0 on success or -errno on failure
     937             :  */
     938             : int spdk_interrupt_mode_enable(void);
     939             : 
     940             : /**
     941             :  * Reports whether interrupt mode is set.
     942             :  *
     943             :  * \return True if interrupt mode is set, false otherwise.
     944             :  */
     945             : bool spdk_interrupt_mode_is_enabled(void);
     946             : 
     947             : /**
     948             :  * A spinlock augmented with safety checks for use with SPDK.
     949             :  *
     950             :  * SPDK code that uses spdk_spinlock runs from an SPDK thread, which itself is associated with a
     951             :  * pthread. There are typically many SPDK threads associated with each pthread. The SPDK application
     952             :  * may migrate SPDK threads between pthreads from time to time to balance the load on those threads.
     953             :  * Migration of SPDK threads only happens when the thread is off CPU, and as such it is only safe to
     954             :  * hold a lock so long as an SPDK thread stays on CPU.
     955             :  *
     956             :  * It is not safe to lock a spinlock, return from the event or poller, then unlock it at some later
     957             :  * time because:
     958             :  *
     959             :  *   - Even though the SPDK thread may be the same, the SPDK thread may be running on different
     960             :  *     pthreads during lock and unlock. A pthread spinlock may consider this to be an unlock by a
     961             :  *     non-owner, which results in undefined behavior.
     962             :  *   - A lock that is acquired by a poller or event may be needed by another poller or event that
     963             :  *     runs on the same pthread. This can lead to deadlock or detection of deadlock.
     964             :  *   - A lock that is acquired by a poller or event that is needed by another poller or event that
     965             :  *     runs on a second pthread will block the second pthread from doing any useful work until the
     966             :  *     lock is released. Because the lock holder and the lock acquirer are on the same pthread, this
     967             :  *     would lead to deadlock.
     968             :  *
     969             :  * If an SPDK spinlock is used erroneously, the program will abort.
     970             :  */
     971             : struct spdk_spinlock {
     972             :         pthread_spinlock_t spinlock;
     973             :         struct spdk_thread *thread;
     974             :         struct spdk_spinlock_internal *internal;
     975             :         bool initialized;
     976             :         bool destroyed;
     977             : };
     978             : 
     979             : /**
     980             :  * Initialize an spdk_spinlock.
     981             :  *
     982             :  * \param sspin The SPDK spinlock to initialize.
     983             :  */
     984             : void spdk_spin_init(struct spdk_spinlock *sspin);
     985             : 
     986             : /**
     987             :  * Destroy an spdk_spinlock.
     988             :  *
     989             :  * \param sspin The SPDK spinlock to initialize.
     990             :  */
     991             : void spdk_spin_destroy(struct spdk_spinlock *sspin);
     992             : 
     993             : /**
     994             :  * Lock an SPDK spin lock.
     995             :  *
     996             :  * \param sspin An SPDK spinlock.
     997             :  */
     998             : void spdk_spin_lock(struct spdk_spinlock *sspin);
     999             : 
    1000             : /**
    1001             :  * Unlock an SPDK spinlock.
    1002             :  *
    1003             :  * \param sspin An SPDK spinlock.
    1004             :  */
    1005             : void spdk_spin_unlock(struct spdk_spinlock *sspin);
    1006             : 
    1007             : /**
    1008             :  * Determine if the caller holds this SPDK spinlock.
    1009             :  *
    1010             :  * \param sspin An SPDK spinlock.
    1011             :  * \return true if spinlock is held by this thread, else false
    1012             :  */
    1013             : bool spdk_spin_held(struct spdk_spinlock *sspin);
    1014             : 
    1015             : struct spdk_iobuf_opts {
    1016             :         /** Maximum number of small buffers */
    1017             :         uint64_t small_pool_count;
    1018             :         /** Maximum number of large buffers */
    1019             :         uint64_t large_pool_count;
    1020             :         /** Size of a single small buffer */
    1021             :         uint32_t small_bufsize;
    1022             :         /** Size of a single large buffer */
    1023             :         uint32_t large_bufsize;
    1024             : 
    1025             :         /**
    1026             :          * The size of spdk_iobuf_opts according to the caller of this library is used for ABI
    1027             :          * compatibility.  The library uses this field to know how many fields in this
    1028             :          * structure are valid. And the library will populate any remaining fields with default values.
    1029             :          * New added fields should be put at the end of the struct.
    1030             :          */
    1031             :         size_t opts_size;
    1032             : 
    1033             : };
    1034             : 
    1035             : struct spdk_iobuf_pool_stats {
    1036             :         /** Buffer got from local per-thread cache */
    1037             :         uint64_t        cache;
    1038             :         /** Buffer got from the main shared pool */
    1039             :         uint64_t        main;
    1040             :         /** Buffer missed and request to get buffer was queued */
    1041             :         uint64_t        retry;
    1042             : };
    1043             : 
    1044             : struct spdk_iobuf_module_stats {
    1045             :         struct spdk_iobuf_pool_stats    small_pool;
    1046             :         struct spdk_iobuf_pool_stats    large_pool;
    1047             :         const char                      *module;
    1048             : };
    1049             : 
    1050             : struct spdk_iobuf_entry;
    1051             : 
    1052             : typedef void (*spdk_iobuf_get_cb)(struct spdk_iobuf_entry *entry, void *buf);
    1053             : 
    1054             : /** iobuf queue entry */
    1055             : struct spdk_iobuf_entry {
    1056             :         spdk_iobuf_get_cb               cb_fn;
    1057             :         const void                      *module;
    1058             :         STAILQ_ENTRY(spdk_iobuf_entry)  stailq;
    1059             : };
    1060             : 
    1061             : struct spdk_iobuf_buffer {
    1062             :         STAILQ_ENTRY(spdk_iobuf_buffer) stailq;
    1063             : };
    1064             : 
    1065             : typedef STAILQ_HEAD(, spdk_iobuf_entry) spdk_iobuf_entry_stailq_t;
    1066             : typedef STAILQ_HEAD(, spdk_iobuf_buffer) spdk_iobuf_buffer_stailq_t;
    1067             : 
    1068             : struct spdk_iobuf_pool {
    1069             :         /** Buffer pool */
    1070             :         struct spdk_ring                *pool;
    1071             :         /** Buffer cache */
    1072             :         spdk_iobuf_buffer_stailq_t      cache;
    1073             :         /** Number of elements in the cache */
    1074             :         uint32_t                        cache_count;
    1075             :         /** Size of the cache */
    1076             :         uint32_t                        cache_size;
    1077             :         /** Buffer wait queue */
    1078             :         spdk_iobuf_entry_stailq_t       *queue;
    1079             :         /** Buffer size */
    1080             :         uint32_t                        bufsize;
    1081             :         /** Pool usage statistics */
    1082             :         struct spdk_iobuf_pool_stats    stats;
    1083             : };
    1084             : 
    1085             : /** iobuf channel */
    1086             : struct spdk_iobuf_channel {
    1087             :         /** Small buffer memory pool */
    1088             :         struct spdk_iobuf_pool          small;
    1089             :         /** Large buffer memory pool */
    1090             :         struct spdk_iobuf_pool          large;
    1091             :         /** Module pointer */
    1092             :         const void                      *module;
    1093             :         /** Parent IO channel */
    1094             :         struct spdk_io_channel          *parent;
    1095             : };
    1096             : 
    1097             : /**
    1098             :  * Initialize and allocate iobuf pools.
    1099             :  *
    1100             :  * \return 0 on success, negative errno otherwise.
    1101             :  */
    1102             : int spdk_iobuf_initialize(void);
    1103             : 
    1104             : typedef void (*spdk_iobuf_finish_cb)(void *cb_arg);
    1105             : 
    1106             : /**
    1107             :  * Clean up and free iobuf pools.
    1108             :  *
    1109             :  * \param cb_fn Callback to be executed once the clean up is completed.
    1110             :  * \param cb_arg Callback argument.
    1111             :  */
    1112             : void spdk_iobuf_finish(spdk_iobuf_finish_cb cb_fn, void *cb_arg);
    1113             : 
    1114             : /**
    1115             :  * Set iobuf options.  These options will be used during `spdk_iobuf_initialize()`.
    1116             :  *
    1117             :  * \param opts Options describing the size of the pools to reserve.
    1118             :  *
    1119             :  * \return 0 on success, negative errno otherwise.
    1120             :  */
    1121             : int spdk_iobuf_set_opts(const struct spdk_iobuf_opts *opts);
    1122             : 
    1123             : /**
    1124             :  * Get iobuf options.
    1125             :  *
    1126             :  * \param opts Output parameter for options.
    1127             :  * \param opts_size sizeof(*opts)
    1128             :  */
    1129             : void spdk_iobuf_get_opts(struct spdk_iobuf_opts *opts, size_t opts_size);
    1130             : 
    1131             : /**
    1132             :  * Register a module as an iobuf pool user.  Only registered users can request buffers from the
    1133             :  * iobuf pool.
    1134             :  *
    1135             :  * \name Name of the module.
    1136             :  *
    1137             :  * \return 0 on success, negative errno otherwise.
    1138             :  */
    1139             : int spdk_iobuf_register_module(const char *name);
    1140             : 
    1141             : /**
    1142             :  * Unregister an iobuf pool user from a module.
    1143             :  *
    1144             :  * \name Name of the module.
    1145             :  *
    1146             :  * \return 0 on success, negative errno otherwise.
    1147             :  */
    1148             : int spdk_iobuf_unregister_module(const char *name);
    1149             : 
    1150             : /**
    1151             :  * Initialize an iobuf channel.
    1152             :  *
    1153             :  * \param ch iobuf channel to initialize.
    1154             :  * \param name Name of the module registered via `spdk_iobuf_register_module()`.
    1155             :  * \param small_cache_size Number of small buffers to be cached by this channel.
    1156             :  * \param large_cache_size Number of large buffers to be cached by this channel.
    1157             :  *
    1158             :  * \return 0 on success, negative errno otherwise.
    1159             :  */
    1160             : int spdk_iobuf_channel_init(struct spdk_iobuf_channel *ch, const char *name,
    1161             :                             uint32_t small_cache_size, uint32_t large_cache_size);
    1162             : 
    1163             : /**
    1164             :  * Release resources tied to an iobuf channel.
    1165             :  *
    1166             :  * \param ch iobuf channel.
    1167             :  */
    1168             : void spdk_iobuf_channel_fini(struct spdk_iobuf_channel *ch);
    1169             : 
    1170             : typedef int (*spdk_iobuf_for_each_entry_fn)(struct spdk_iobuf_channel *ch,
    1171             :                 struct spdk_iobuf_entry *entry, void *ctx);
    1172             : 
    1173             : /**
    1174             :  * Iterate over all entries on a given queue and execute a callback on those that were requested
    1175             :  * using `ch`.  The iteration is stopped if the callback returns non-zero status.
    1176             :  *
    1177             :  * \param ch iobuf channel to iterate over.
    1178             :  * \param pool Pool to iterate over (`small` or `large`).
    1179             :  * \param cb_fn Callback to execute on each entry on the queue that was requested using `ch`.
    1180             :  * \param cb_ctx Argument passed to `cb_fn`.
    1181             :  *
    1182             :  * \return status of the last callback.
    1183             :  */
    1184             : int spdk_iobuf_for_each_entry(struct spdk_iobuf_channel *ch, struct spdk_iobuf_pool *pool,
    1185             :                               spdk_iobuf_for_each_entry_fn cb_fn, void *cb_ctx);
    1186             : 
    1187             : /**
    1188             :  * Abort an outstanding request waiting for a buffer.
    1189             :  *
    1190             :  * \param ch iobuf channel on which the entry is waiting.
    1191             :  * \param entry Entry to remove from the wait queue.
    1192             :  * \param len Length of the requested buffer (must be the exact same value as specified in
    1193             :  *            `spdk_iobuf_get()`.
    1194             :  */
    1195             : void spdk_iobuf_entry_abort(struct spdk_iobuf_channel *ch, struct spdk_iobuf_entry *entry,
    1196             :                             uint64_t len);
    1197             : 
    1198             : /**
    1199             :  * Get a buffer from the iobuf pool. If no buffers are available and entry with cb_fn provided
    1200             :  * then the request is queued until a buffer becomes available.
    1201             :  *
    1202             :  * \param ch iobuf channel.
    1203             :  * \param len Length of the buffer to retrieve. The user is responsible for making sure the length
    1204             :  *            doesn't exceed large_bufsize.
    1205             :  * \param entry Wait queue entry (optional).
    1206             :  * \param cb_fn Callback to be executed once a buffer becomes available. If a buffer is available
    1207             :  *              immediately, it is NOT executed. Mandatory only if entry provided.
    1208             :  *
    1209             :  * \return pointer to a buffer or NULL if no buffers are currently available.
    1210             :  */
    1211             : void *spdk_iobuf_get(struct spdk_iobuf_channel *ch, uint64_t len, struct spdk_iobuf_entry *entry,
    1212             :                      spdk_iobuf_get_cb cb_fn);
    1213             : 
    1214             : /**
    1215             :  * Release a buffer back to the iobuf pool.  If there are outstanding requests waiting for a buffer,
    1216             :  * this buffer will be passed to one of them.
    1217             :  *
    1218             :  * \param ch iobuf channel.
    1219             :  * \param buf Buffer to release
    1220             :  * \param len Length of the buffer (must be the exact same value as specified in `spdk_iobuf_get()`).
    1221             :  */
    1222             : void spdk_iobuf_put(struct spdk_iobuf_channel *ch, void *buf, uint64_t len);
    1223             : 
    1224             : typedef void (*spdk_iobuf_get_stats_cb)(struct spdk_iobuf_module_stats *modules,
    1225             :                                         uint32_t num_modules, void *cb_arg);
    1226             : 
    1227             : /**
    1228             :  * Get iobuf statistics.
    1229             :  *
    1230             :  * \param cb_fn Callback to be executed once stats are gathered.
    1231             :  * \param cb_arg Argument passed to the callback function.
    1232             :  *
    1233             :  * \return 0 on success, negative errno otherwise.
    1234             :  */
    1235             : int spdk_iobuf_get_stats(spdk_iobuf_get_stats_cb cb_fn, void *cb_arg);
    1236             : 
    1237             : #ifdef __cplusplus
    1238             : }
    1239             : #endif
    1240             : 
    1241             : #endif /* SPDK_THREAD_H_ */

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