ee66e58e0a
This patch adds a basic framework for creating I/O channels for I/O devices. An spdk_io_channel represents a one-to-one mapping between a calling thread (represented by spdk_thread) and an I/O device that the thread will perform I/O operations on. Signed-off-by: Jim Harris <james.r.harris@intel.com> Change-Id: I658ab7f995cc962f4e2a204e058cdd3ad3fd735d
118 lines
4.6 KiB
C
118 lines
4.6 KiB
C
/*-
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* BSD LICENSE
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*
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* Copyright (c) Intel Corporation.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* * Neither the name of Intel Corporation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/** \file
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* IO channel
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*/
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#ifndef SPDK_IO_CHANNEL_H_
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#define SPDK_IO_CHANNEL_H_
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#include <inttypes.h>
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#include "spdk/queue.h"
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#define SPDK_IO_PRIORITY_DEFAULT 100
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struct spdk_io_channel;
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typedef int (*io_channel_create_cb_t)(void *io_device, uint32_t priority, void *ctx_buf);
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typedef void (*io_channel_destroy_cb_t)(void *io_device, void *ctx_buf);
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/**
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* \brief Initializes the calling thread for I/O channel allocation.
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*/
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void spdk_allocate_thread(void);
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/**
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* \brief Releases any resources related to the calling thread for I/O channel allocation.
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*
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* All I/O channel references related to the calling thread must be released using
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* spdk_put_io_channel() prior to calling this function.
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*/
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void spdk_free_thread(void);
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/**
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* \brief Register the opaque io_device context as an I/O device.
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*
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* After an I/O device is registered, it can return I/O channels using the
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* spdk_get_io_channel() function. create_cb is the callback function invoked
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* to allocate any resources required for a new I/O channel. destroy_cb is the
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* callback function invoked to release the resources for an I/O channel. ctx_size
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* is the size of the context buffer allocated to store references to allocated I/O
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* channel resources.
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*/
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void spdk_io_device_register(void *io_device, io_channel_create_cb_t create_cb,
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io_channel_destroy_cb_t destroy_cb, uint32_t ctx_size);
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/**
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* \brief Unregister the opaque io_device context as an I/O device.
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*
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* Callers must ensure they release references to any I/O channel related to this
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* device before calling this function.
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*/
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void spdk_io_device_unregister(void *io_device);
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/**
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* \brief Gets an I/O channel for the specified io_device to be used by the calling thread.
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*
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* The io_device context pointer specified must have previously been registered using
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* spdk_io_device_register(). If an existing I/O channel does not exist yet for the given
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* io_device on the calling thread, it will allocate an I/O channel and invoke the create_cb
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* function pointer specified in spdk_io_device_register(). If an I/O channel already
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* exists for the given io_device on the calling thread, its reference is returned rather
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* than creating a new I/O channel.
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*
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* The priority parameter allows callers to create different I/O channels to the same
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* I/O device with varying priorities. Currently this value must be set to
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* SPDK_IO_PRIORITY_DEFAULT.
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*/
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struct spdk_io_channel *spdk_get_io_channel(void *io_device, uint32_t priority);
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/**
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* \brief Releases a reference to an I/O channel.
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*
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* Must be called from the same thread that called spdk_get_io_channel() for the specified
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* I/O channel. If this releases the last reference to the I/O channel, The destroy_cb
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* function specified in spdk_io_device_register() will be invoked to release any
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* associated resources.
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*/
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void spdk_put_io_channel(struct spdk_io_channel *ch);
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/**
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* \brief Returns the context buffer associated with an I/O channel.
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*/
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void *spdk_io_channel_get_ctx(struct spdk_io_channel *ch);
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#endif /* SPDK_IO_CHANNEL_H_ */
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