numam-spdk/lib/accel/accel_engine.c

/*-
 *   BSD LICENSE
 *
 *   Copyright (c) Intel Corporation.
 *   All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions
 *   are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *     * Neither the name of Intel Corporation nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "spdk/stdinc.h"

#include "spdk_internal/accel_engine.h"

#include "spdk/env.h"
#include "spdk/likely.h"
#include "spdk/log.h"
#include "spdk/thread.h"
#include "spdk/json.h"
#include "spdk/crc32.h"
#include "spdk/util.h"

/* Accelerator Engine Framework: The following provides a top level
 * generic API for the accelerator functions defined here. Modules,
 * such as the one in /module/accel/ioat, supply the implemention
 * with the exception of the pure software implemention contained
 * later in this file.
 */

#define ALIGN_4K			0x1000
#define MAX_TASKS_PER_CHANNEL		0x800
#define MAX_BATCH_SIZE			0x10
#define MAX_NUM_BATCHES_PER_CHANNEL	(MAX_TASKS_PER_CHANNEL / MAX_BATCH_SIZE)

/* Largest context size for all accel modules */
static size_t g_max_accel_module_size = 0;

static struct spdk_accel_engine *g_hw_accel_engine = NULL;
static struct spdk_accel_engine *g_sw_accel_engine = NULL;
static struct spdk_accel_module_if *g_accel_engine_module = NULL;
static spdk_accel_fini_cb g_fini_cb_fn = NULL;
static void *g_fini_cb_arg = NULL;

/* Global list of registered accelerator modules */
static TAILQ_HEAD(, spdk_accel_module_if) spdk_accel_module_list =
	TAILQ_HEAD_INITIALIZER(spdk_accel_module_list);

static void _sw_accel_dualcast(void *dst1, void *dst2, void *src, uint64_t nbytes);
static void _sw_accel_copy(void *dst, void *src, uint64_t nbytes);
static int _sw_accel_compare(void *src1, void *src2, uint64_t nbytes);
static void _sw_accel_fill(void *dst, uint8_t fill, uint64_t nbytes);
static void _sw_accel_crc32c(uint32_t *dst, void *src, uint32_t seed, uint64_t nbytes);
static void _sw_accel_crc32cv(uint32_t *dst, struct iovec *iov, uint32_t iovcnt, uint32_t seed);

/* Registration of hw modules (currently supports only 1 at a time) */
void
spdk_accel_hw_engine_register(struct spdk_accel_engine *accel_engine)
{
	if (g_hw_accel_engine == NULL) {
		g_hw_accel_engine = accel_engine;
	} else {
		SPDK_NOTICELOG("Hardware offload engine already enabled\n");
	}
}

/* Registration of sw modules (currently supports only 1) */
static void
accel_sw_register(struct spdk_accel_engine *accel_engine)
{
	assert(g_sw_accel_engine == NULL);
	g_sw_accel_engine = accel_engine;
}

static void
accel_sw_unregister(void)
{
	g_sw_accel_engine = NULL;
}

/* Used to determine whether a command is sent to an engine/module or done here
 * via SW implementation.
 */
inline static bool
_is_supported(struct spdk_accel_engine *engine, enum accel_capability operation)
{
	return ((engine->capabilities & operation) == operation);
}

void
spdk_accel_task_complete(struct spdk_accel_task *accel_task, int status)
{
	struct accel_io_channel *accel_ch = accel_task->accel_ch;
	struct spdk_accel_batch *batch = accel_task->batch;
	spdk_accel_completion_cb	cb_fn = accel_task->cb_fn;
	void				*cb_arg = accel_task->cb_arg;

	/* We should put the accel_task into the list firstly in order to avoid
	 * the accel task list is exhausted when there is recursive call to
	 * allocate accel_task in user's call back function (cb_fn)
	 */
	TAILQ_INSERT_TAIL(&accel_ch->task_pool, accel_task, link);

	cb_fn(cb_arg, status);
	/* If this task is part of a batch, check for completion of the batch. */
	if (batch) {
		assert(batch->count > 0);
		batch->count--;
		if (batch->count == 0) {
			SPDK_DEBUGLOG(accel, "Batch %p count %d\n", batch, batch->count);
			if (batch->cb_fn) {
				batch->cb_fn(batch->cb_arg, batch->status);
			}
			TAILQ_REMOVE(&accel_ch->batches, batch, link);
			TAILQ_INSERT_TAIL(&accel_ch->batch_pool, batch, link);
		}
	}
}

/* Accel framework public API for discovering current engine capabilities. */
uint64_t
spdk_accel_get_capabilities(struct spdk_io_channel *ch)
{
	struct accel_io_channel *accel_ch = spdk_io_channel_get_ctx(ch);

	return accel_ch->engine->capabilities;
}

inline static bool
_is_batch_valid(struct spdk_accel_batch *batch, struct accel_io_channel *accel_ch)
{
	return (batch->accel_ch == accel_ch);
}

inline static struct spdk_accel_task *
_get_task(struct accel_io_channel *accel_ch, struct spdk_accel_batch *batch,
	  spdk_accel_completion_cb cb_fn, void *cb_arg)
{
	struct spdk_accel_task *accel_task;

	if (batch && _is_batch_valid(batch, accel_ch) == false) {
		SPDK_ERRLOG("Attempt to access an invalid batch.\n.");
		return NULL;
	}

	accel_task = TAILQ_FIRST(&accel_ch->task_pool);
	if (accel_task == NULL) {
		return NULL;
	}
	TAILQ_REMOVE(&accel_ch->task_pool, accel_task, link);
	accel_task->link.tqe_next = NULL;
	accel_task->link.tqe_prev = NULL;

	accel_task->cb_fn = cb_fn;
	accel_task->cb_arg = cb_arg;
	accel_task->accel_ch = accel_ch;
	accel_task->batch = batch;
	if (batch) {
		batch->count++;
	}

	return accel_task;
}

/* Accel framework public API for copy function */
int
spdk_accel_submit_copy(struct spdk_io_channel *ch, void *dst, void *src, uint64_t nbytes,
		       spdk_accel_completion_cb cb_fn, void *cb_arg)
{
	struct accel_io_channel *accel_ch = spdk_io_channel_get_ctx(ch);
	struct spdk_accel_task *accel_task;

	accel_task = _get_task(accel_ch, NULL, cb_fn, cb_arg);
	if (accel_task == NULL) {
		return -ENOMEM;
	}

	accel_task->dst = dst;
	accel_task->src = src;
	accel_task->op_code = ACCEL_OPCODE_MEMMOVE;
	accel_task->nbytes = nbytes;

	if (_is_supported(accel_ch->engine, ACCEL_COPY)) {
		return accel_ch->engine->submit_tasks(accel_ch->engine_ch, accel_task);
	} else {
		_sw_accel_copy(dst, src, nbytes);
		spdk_accel_task_complete(accel_task, 0);
		return 0;
	}
}

/* Accel framework public API for dual cast copy function */
int
spdk_accel_submit_dualcast(struct spdk_io_channel *ch, void *dst1, void *dst2, void *src,
			   uint64_t nbytes, spdk_accel_completion_cb cb_fn, void *cb_arg)
{
	struct accel_io_channel *accel_ch = spdk_io_channel_get_ctx(ch);
	struct spdk_accel_task *accel_task;

	if ((uintptr_t)dst1 & (ALIGN_4K - 1) || (uintptr_t)dst2 & (ALIGN_4K - 1)) {
		SPDK_ERRLOG("Dualcast requires 4K alignment on dst addresses\n");
		return -EINVAL;
	}

	accel_task = _get_task(accel_ch, NULL, cb_fn, cb_arg);
	if (accel_task == NULL) {
		return -ENOMEM;
	}

	accel_task->src = src;
	accel_task->dst = dst1;
	accel_task->dst2 = dst2;
	accel_task->nbytes = nbytes;
	accel_task->op_code = ACCEL_OPCODE_DUALCAST;

	if (_is_supported(accel_ch->engine, ACCEL_DUALCAST)) {
		return accel_ch->engine->submit_tasks(accel_ch->engine_ch, accel_task);
	} else {
		_sw_accel_dualcast(dst1, dst2, src, nbytes);
		spdk_accel_task_complete(accel_task, 0);
		return 0;
	}
}

/* Accel framework public API for compare function */
int
spdk_accel_submit_compare(struct spdk_io_channel *ch, void *src1, void *src2, uint64_t nbytes,
			  spdk_accel_completion_cb cb_fn, void *cb_arg)
{
	struct accel_io_channel *accel_ch = spdk_io_channel_get_ctx(ch);
	struct spdk_accel_task *accel_task;
	int rc;

	accel_task = _get_task(accel_ch, NULL, cb_fn, cb_arg);
	if (accel_task == NULL) {
		return -ENOMEM;
	}

	accel_task->src = src1;
	accel_task->src2 = src2;
	accel_task->nbytes = nbytes;
	accel_task->op_code = ACCEL_OPCODE_COMPARE;

	if (_is_supported(accel_ch->engine, ACCEL_COMPARE)) {
		return accel_ch->engine->submit_tasks(accel_ch->engine_ch, accel_task);
	} else {
		rc = _sw_accel_compare(src1, src2, nbytes);
		spdk_accel_task_complete(accel_task, rc);
		return 0;
	}
}

/* Accel framework public API for fill function */
int
spdk_accel_submit_fill(struct spdk_io_channel *ch, void *dst, uint8_t fill, uint64_t nbytes,
		       spdk_accel_completion_cb cb_fn, void *cb_arg)
{
	struct accel_io_channel *accel_ch = spdk_io_channel_get_ctx(ch);
	struct spdk_accel_task *accel_task;

	accel_task = _get_task(accel_ch, NULL, cb_fn, cb_arg);
	if (accel_task == NULL) {
		return -ENOMEM;
	}

	accel_task->dst = dst;
	accel_task->fill_pattern = fill;
	accel_task->nbytes = nbytes;
	accel_task->op_code = ACCEL_OPCODE_MEMFILL;

	if (_is_supported(accel_ch->engine, ACCEL_FILL)) {
		return accel_ch->engine->submit_tasks(accel_ch->engine_ch, accel_task);
	} else {
		_sw_accel_fill(dst, fill, nbytes);
		spdk_accel_task_complete(accel_task, 0);
		return 0;
	}
}

/* Accel framework public API for CRC-32C function */
int
spdk_accel_submit_crc32c(struct spdk_io_channel *ch, uint32_t *dst, void *src, uint32_t seed,
			 uint64_t nbytes, spdk_accel_completion_cb cb_fn, void *cb_arg)
{
	struct accel_io_channel *accel_ch = spdk_io_channel_get_ctx(ch);
	struct spdk_accel_task *accel_task;

	accel_task = _get_task(accel_ch, NULL, cb_fn, cb_arg);
	if (accel_task == NULL) {
		return -ENOMEM;
	}

	accel_task->dst = (void *)dst;
	accel_task->src = src;
	accel_task->v.iovcnt = 0;
	accel_task->seed = seed;
	accel_task->nbytes = nbytes;
	accel_task->op_code = ACCEL_OPCODE_CRC32C;

	if (_is_supported(accel_ch->engine, ACCEL_CRC32C)) {
		return accel_ch->engine->submit_tasks(accel_ch->engine_ch, accel_task);
	} else {
		_sw_accel_crc32c(dst, src, seed, nbytes);
		spdk_accel_task_complete(accel_task, 0);
		return 0;
	}
}

static void
crc32cv_done(void *cb_arg, int status)
{
	struct spdk_accel_task *accel_task = cb_arg;
	struct spdk_io_channel *ch = spdk_io_channel_from_ctx(accel_task->accel_ch);

	assert(accel_task->chained.cb_fn != NULL);
	assert(accel_task->chained.cb_arg != NULL);

	if (spdk_likely(!status)) {
		status = spdk_accel_submit_crc32cv(ch, accel_task->dst, ++accel_task->v.iovs,
						   accel_task->v.iovcnt - 1, ~(*((uint32_t *)accel_task->dst)),
						   accel_task->chained.cb_fn, accel_task->chained.cb_arg);
		if (spdk_likely(!status)) {
			return;
		}
	}

	accel_task->chained.cb_fn(accel_task->chained.cb_arg, status);
}

/* Accel framework public API for chained CRC-32C function */
int
spdk_accel_submit_crc32cv(struct spdk_io_channel *ch, uint32_t *dst, struct iovec *iov,
			  uint32_t iov_cnt, uint32_t seed, spdk_accel_completion_cb cb_fn, void *cb_arg)
{
	struct accel_io_channel *accel_ch;
	struct spdk_accel_task *accel_task;

	if (iov == NULL) {
		SPDK_ERRLOG("iov should not be NULL");
		return -EINVAL;
	}

	if (!iov_cnt) {
		SPDK_ERRLOG("iovcnt should not be zero value\n");
		return -EINVAL;
	}

	if (iov_cnt == 1) {
		return spdk_accel_submit_crc32c(ch, dst, iov[0].iov_base, seed, iov[0].iov_len, cb_fn, cb_arg);
	}

	accel_ch = spdk_io_channel_get_ctx(ch);
	accel_task = _get_task(accel_ch, NULL, cb_fn, cb_arg);
	if (accel_task == NULL) {
		SPDK_ERRLOG("no memory\n");
		assert(0);
		return -ENOMEM;
	}

	accel_task->v.iovs = iov;
	accel_task->v.iovcnt = iov_cnt;
	accel_task->dst = (void *)dst;
	accel_task->op_code = ACCEL_OPCODE_CRC32C;

	if (_is_supported(accel_ch->engine, ACCEL_CRC32C)) {
		accel_task->cb_fn = crc32cv_done;
		accel_task->cb_arg = accel_task;
		accel_task->chained.cb_fn = cb_fn;
		accel_task->chained.cb_arg = cb_arg;

		accel_task->src = iov[0].iov_base;
		accel_task->nbytes = iov[0].iov_len;

		return accel_ch->engine->submit_tasks(accel_ch->engine_ch, accel_task);
	} else {
		_sw_accel_crc32cv(dst, iov, iov_cnt, seed);
		spdk_accel_task_complete(accel_task, 0);
		return 0;
	}
}

/* Accel framework public API for getting max operations for a batch. */
uint32_t
spdk_accel_batch_get_max(struct spdk_io_channel *ch)
{
	struct accel_io_channel *accel_ch = spdk_io_channel_get_ctx(ch);

	/* Use the smaller of the currently selected engine or pure SW implementation. */
	return spdk_min(accel_ch->engine->batch_get_max(accel_ch->engine_ch),
			MAX_BATCH_SIZE);
}

int
spdk_accel_batch_prep_copy(struct spdk_io_channel *ch, struct spdk_accel_batch *batch, void *dst,
			   void *src, uint64_t nbytes, spdk_accel_completion_cb cb_fn, void *cb_arg)
{
	struct accel_io_channel *accel_ch = spdk_io_channel_get_ctx(ch);
	struct spdk_accel_task *accel_task;

	accel_task = _get_task(accel_ch, batch, cb_fn, cb_arg);
	if (accel_task == NULL) {
		return -ENOMEM;
	}

	accel_task->src = src;
	accel_task->dst = dst;
	accel_task->nbytes = nbytes;
	accel_task->op_code = ACCEL_OPCODE_MEMMOVE;

	if (_is_supported(accel_ch->engine, ACCEL_COPY)) {
		TAILQ_INSERT_TAIL(&batch->hw_tasks, accel_task, link);
	} else {
		TAILQ_INSERT_TAIL(&batch->sw_tasks, accel_task, link);
	}

	return 0;
}

int
spdk_accel_batch_prep_dualcast(struct spdk_io_channel *ch, struct spdk_accel_batch *batch,
			       void *dst1, void *dst2, void *src, uint64_t nbytes,
			       spdk_accel_completion_cb cb_fn, void *cb_arg)
{
	struct spdk_accel_task *accel_task;
	struct accel_io_channel *accel_ch = spdk_io_channel_get_ctx(ch);

	if ((uintptr_t)dst1 & (ALIGN_4K - 1) || (uintptr_t)dst2 & (ALIGN_4K - 1)) {
		SPDK_ERRLOG("Dualcast requires 4K alignment on dst addresses\n");
		return -EINVAL;
	}

	accel_task = _get_task(accel_ch, batch, cb_fn, cb_arg);
	if (accel_task == NULL) {
		return -ENOMEM;
	}

	accel_task->src = src;
	accel_task->dst = dst1;
	accel_task->dst2 = dst2;
	accel_task->nbytes = nbytes;
	accel_task->op_code = ACCEL_OPCODE_DUALCAST;

	if (_is_supported(accel_ch->engine, ACCEL_DUALCAST)) {
		TAILQ_INSERT_TAIL(&batch->hw_tasks, accel_task, link);
	} else {
		TAILQ_INSERT_TAIL(&batch->sw_tasks, accel_task, link);
	}

	return 0;
}

int
spdk_accel_batch_prep_compare(struct spdk_io_channel *ch, struct spdk_accel_batch *batch,
			      void *src1, void *src2, uint64_t nbytes, spdk_accel_completion_cb cb_fn,
			      void *cb_arg)
{
	struct spdk_accel_task *accel_task;
	struct accel_io_channel *accel_ch = spdk_io_channel_get_ctx(ch);

	accel_task = _get_task(accel_ch, batch, cb_fn, cb_arg);
	if (accel_task == NULL) {
		return -ENOMEM;
	}

	accel_task->src = src1;
	accel_task->src2 = src2;
	accel_task->nbytes = nbytes;
	accel_task->op_code = ACCEL_OPCODE_COMPARE;

	if (_is_supported(accel_ch->engine, ACCEL_COMPARE)) {
		TAILQ_INSERT_TAIL(&batch->hw_tasks, accel_task, link);
	} else {
		TAILQ_INSERT_TAIL(&batch->sw_tasks, accel_task, link);
	}

	return 0;
}

int
spdk_accel_batch_prep_fill(struct spdk_io_channel *ch, struct spdk_accel_batch *batch, void *dst,
			   uint8_t fill, uint64_t nbytes, spdk_accel_completion_cb cb_fn, void *cb_arg)
{
	struct spdk_accel_task *accel_task;
	struct accel_io_channel *accel_ch = spdk_io_channel_get_ctx(ch);

	accel_task = _get_task(accel_ch, batch, cb_fn, cb_arg);
	if (accel_task == NULL) {
		return -ENOMEM;
	}

	accel_task->dst = dst;
	accel_task->fill_pattern = fill;
	accel_task->nbytes = nbytes;
	accel_task->op_code = ACCEL_OPCODE_MEMFILL;

	if (_is_supported(accel_ch->engine, ACCEL_FILL)) {
		TAILQ_INSERT_TAIL(&batch->hw_tasks, accel_task, link);
	} else {
		TAILQ_INSERT_TAIL(&batch->sw_tasks, accel_task, link);
	}

	return 0;
}

int
spdk_accel_batch_prep_crc32c(struct spdk_io_channel *ch, struct spdk_accel_batch *batch,
			     uint32_t *dst, void *src, uint32_t seed, uint64_t nbytes,
			     spdk_accel_completion_cb cb_fn, void *cb_arg)
{
	struct spdk_accel_task *accel_task;
	struct accel_io_channel *accel_ch = spdk_io_channel_get_ctx(ch);

	accel_task = _get_task(accel_ch, batch, cb_fn, cb_arg);
	if (accel_task == NULL) {
		return -ENOMEM;
	}

	accel_task->dst = dst;
	accel_task->src = src;
	accel_task->v.iovcnt = 0;
	accel_task->seed = seed;
	accel_task->nbytes = nbytes;
	accel_task->op_code = ACCEL_OPCODE_CRC32C;

	if (_is_supported(accel_ch->engine, ACCEL_CRC32C)) {
		TAILQ_INSERT_TAIL(&batch->hw_tasks, accel_task, link);
	} else {
		TAILQ_INSERT_TAIL(&batch->sw_tasks, accel_task, link);
	}

	return 0;
}

static void
batched_crc32cv_done(void *cb_arg, int status)
{
	struct spdk_accel_task *accel_task = cb_arg;
	struct spdk_io_channel *ch = spdk_io_channel_from_ctx(accel_task->accel_ch);
	struct spdk_accel_batch *batch;

	batch = accel_task->batch;
	assert(batch != NULL);
	assert(accel_task->chained.cb_fn != NULL);
	assert(accel_task->chained.cb_arg != NULL);

	if (spdk_likely(!status)) {
		status = spdk_accel_batch_prep_crc32cv(ch, batch, accel_task->dst,
						       ++accel_task->v.iovs, accel_task->v.iovcnt - 1,  ~(*((uint32_t *)accel_task->dst)),
						       accel_task->chained.cb_fn, accel_task->chained.cb_arg);
		if (spdk_likely(!status)) {
			return;
		}
	}

	accel_task->chained.cb_fn(accel_task->chained.cb_arg, status);
}

int
spdk_accel_batch_prep_crc32cv(struct spdk_io_channel *ch, struct spdk_accel_batch *batch,
			      uint32_t *dst, struct iovec *iovs, uint32_t iov_cnt, uint32_t seed,
			      spdk_accel_completion_cb cb_fn, void *cb_arg)
{
	struct accel_io_channel *accel_ch;
	struct spdk_accel_task *accel_task;

	if (iovs == NULL) {
		SPDK_ERRLOG("iovs should not be NULL\n");
		return -EINVAL;
	}

	if (iov_cnt == 0) {
		SPDK_ERRLOG("iovcnt should not be zero value\n");
		return -EINVAL;
	}

	if (iov_cnt == 1) {
		return spdk_accel_batch_prep_crc32c(ch, batch, dst, iovs[0].iov_base, seed, iovs[0].iov_len, cb_fn,
						    cb_arg);
	}

	accel_ch = spdk_io_channel_get_ctx(ch);
	accel_task = _get_task(accel_ch, batch, cb_fn, cb_arg);
	if (accel_task == NULL) {
		return -ENOMEM;
	}

	accel_task->v.iovs = iovs;
	accel_task->v.iovcnt = iov_cnt;
	accel_task->dst = dst;
	accel_task->seed = seed;
	accel_task->op_code = ACCEL_OPCODE_CRC32C;

	if (_is_supported(accel_ch->engine, ACCEL_CRC32C)) {
		accel_task->cb_arg = accel_task;
		accel_task->cb_fn = batched_crc32cv_done;
		accel_task->cb_arg = accel_task;
		accel_task->chained.cb_fn = cb_fn;
		accel_task->chained.cb_arg = cb_arg;

		accel_task->src = iovs[0].iov_base;
		accel_task->nbytes = iovs[0].iov_len;

		TAILQ_INSERT_TAIL(&batch->hw_tasks, accel_task, link);
	} else {
		TAILQ_INSERT_TAIL(&batch->sw_tasks, accel_task, link);
	}

	return 0;
}

/* Accel framework public API for batch_create function. */
struct spdk_accel_batch *
spdk_accel_batch_create(struct spdk_io_channel *ch)
{
	struct accel_io_channel *accel_ch = spdk_io_channel_get_ctx(ch);
	struct spdk_accel_batch *batch;

	batch = TAILQ_FIRST(&accel_ch->batch_pool);
	if (batch == NULL) {
		/* The application needs to handle this case (no batches available) */
		return NULL;
	}

	TAILQ_REMOVE(&accel_ch->batch_pool, batch, link);
	TAILQ_INIT(&batch->hw_tasks);
	TAILQ_INIT(&batch->sw_tasks);
	batch->count = batch->status = 0;
	batch->accel_ch = accel_ch;
	TAILQ_INSERT_TAIL(&accel_ch->batches, batch, link);
	SPDK_DEBUGLOG(accel, "Create batch %p\n", batch);

	return (struct spdk_accel_batch *)batch;
}

/* Accel framework public API for batch_submit function. */
int
spdk_accel_batch_submit(struct spdk_io_channel *ch, struct spdk_accel_batch *batch,
			spdk_accel_completion_cb cb_fn, void *cb_arg)
{
	struct accel_io_channel *accel_ch = spdk_io_channel_get_ctx(ch);
	struct spdk_accel_task *accel_task, *next_task;
	int rc = 0;

	if (_is_batch_valid(batch, accel_ch) == false) {
		SPDK_ERRLOG("Attempt to access an invalid batch.\n.");
		return -EINVAL;
	}

	batch->cb_fn = cb_fn;
	batch->cb_arg = cb_arg;

	/* Process any HW commands. */
	if (!TAILQ_EMPTY(&batch->hw_tasks)) {
		accel_task = TAILQ_FIRST(&batch->hw_tasks);

		/* Clear the hw_tasks list but leave the tasks linked. */
		TAILQ_INIT(&batch->hw_tasks);

		/* The submit_tasks function will always return success and use the
		 * task callbacks to report errors.
		 */
		accel_ch->engine->submit_tasks(accel_ch->engine_ch, accel_task);
	}

	/* Process any SW commands. */
	accel_task = TAILQ_FIRST(&batch->sw_tasks);

	/* Clear the hw_tasks list but leave the tasks linked. */
	TAILQ_INIT(&batch->sw_tasks);

	while (accel_task) {
		/* Grab the next task now before it's returned to the pool in the cb_fn. */
		next_task = TAILQ_NEXT(accel_task, link);

		switch (accel_task->op_code) {
		case ACCEL_OPCODE_MEMMOVE:
			_sw_accel_copy(accel_task->dst, accel_task->src, accel_task->nbytes);
			spdk_accel_task_complete(accel_task, 0);
			break;
		case ACCEL_OPCODE_MEMFILL:
			_sw_accel_fill(accel_task->dst, accel_task->fill_pattern, accel_task->nbytes);
			spdk_accel_task_complete(accel_task, 0);
			break;
		case ACCEL_OPCODE_COMPARE:
			rc = _sw_accel_compare(accel_task->src, accel_task->src2, accel_task->nbytes);
			spdk_accel_task_complete(accel_task, rc);
			batch->status |= rc;
			break;
		case ACCEL_OPCODE_CRC32C:
			if (accel_task->v.iovcnt == 0) {
				_sw_accel_crc32c(accel_task->dst, accel_task->src, accel_task->seed,
						 accel_task->nbytes);
			} else {
				_sw_accel_crc32cv(accel_task->dst, accel_task->v.iovs, accel_task->v.iovcnt, accel_task->seed);
			}
			spdk_accel_task_complete(accel_task, 0);
			break;
		case ACCEL_OPCODE_DUALCAST:
			_sw_accel_dualcast(accel_task->dst, accel_task->dst2, accel_task->src,
					   accel_task->nbytes);
			spdk_accel_task_complete(accel_task, 0);
			break;
		default:
			assert(false);
			break;
		}
		accel_task = next_task;
	};

	/* There are no submission errors possible at this point. Any possible errors will
	 * happen in the task cb_fn calls and OR'd into the batch->status.
	 */
	return 0;
}

/* Accel framework public API for batch cancel function. If the engine does
 * not support batching it is done here at the accel_fw level.
 */
int
spdk_accel_batch_cancel(struct spdk_io_channel *ch, struct spdk_accel_batch *batch)
{
	struct accel_io_channel *accel_ch = spdk_io_channel_get_ctx(ch);
	struct spdk_accel_task *accel_task;

	/* Cancel anything currently oustanding for this batch. */
	while ((batch = TAILQ_FIRST(&accel_ch->batches))) {
		TAILQ_REMOVE(&accel_ch->batches, batch, link);
		while ((accel_task = TAILQ_FIRST(&batch->hw_tasks))) {
			TAILQ_REMOVE(&batch->hw_tasks, accel_task, link);
			TAILQ_INSERT_TAIL(&accel_ch->task_pool, accel_task, link);
		}
		while ((accel_task = TAILQ_FIRST(&batch->sw_tasks))) {
			TAILQ_REMOVE(&batch->sw_tasks, accel_task, link);
			TAILQ_INSERT_TAIL(&accel_ch->task_pool, accel_task, link);
		}
		TAILQ_INSERT_TAIL(&accel_ch->batch_pool, batch, link);
	}

	return 0;
}

/* Helper function when when accel modules register with the framework. */
void spdk_accel_module_list_add(struct spdk_accel_module_if *accel_module)
{
	TAILQ_INSERT_TAIL(&spdk_accel_module_list, accel_module, tailq);
	if (accel_module->get_ctx_size && accel_module->get_ctx_size() > g_max_accel_module_size) {
		g_max_accel_module_size = accel_module->get_ctx_size();
	}
}

/* Framework level channel create callback. */
static int
accel_engine_create_cb(void *io_device, void *ctx_buf)
{
	struct accel_io_channel	*accel_ch = ctx_buf;
	struct spdk_accel_task *accel_task;
	uint8_t *task_mem;
	struct spdk_accel_batch *batch;
	int i;

	accel_ch->task_pool_base = calloc(MAX_TASKS_PER_CHANNEL, g_max_accel_module_size);
	if (accel_ch->task_pool_base == NULL) {
		return -ENOMEM;
	}

	TAILQ_INIT(&accel_ch->task_pool);
	task_mem = accel_ch->task_pool_base;
	for (i = 0 ; i < MAX_TASKS_PER_CHANNEL; i++) {
		accel_task = (struct spdk_accel_task *)task_mem;
		TAILQ_INSERT_TAIL(&accel_ch->task_pool, accel_task, link);
		task_mem += g_max_accel_module_size;
	}

	TAILQ_INIT(&accel_ch->batch_pool);
	TAILQ_INIT(&accel_ch->batches);
	accel_ch->batch_pool_base = calloc(MAX_NUM_BATCHES_PER_CHANNEL, sizeof(struct spdk_accel_batch));
	if (accel_ch->batch_pool_base == NULL) {
		free(accel_ch->task_pool_base);
		return -ENOMEM;
	}

	batch = (struct spdk_accel_batch *)accel_ch->batch_pool_base;
	for (i = 0 ; i < MAX_NUM_BATCHES_PER_CHANNEL; i++) {
		TAILQ_INSERT_TAIL(&accel_ch->batch_pool, batch, link);
		batch++;
	}

	if (g_hw_accel_engine != NULL) {
		accel_ch->engine_ch = g_hw_accel_engine->get_io_channel();
		accel_ch->engine = g_hw_accel_engine;
	} else {
		/* No hw engine enabled, use sw. */
		accel_ch->engine_ch = g_sw_accel_engine->get_io_channel();
		accel_ch->engine = g_sw_accel_engine;
	}
	assert(accel_ch->engine_ch != NULL);
	accel_ch->engine->capabilities = accel_ch->engine->get_capabilities();

	return 0;
}

/* Framework level channel destroy callback. */
static void
accel_engine_destroy_cb(void *io_device, void *ctx_buf)
{
	struct accel_io_channel	*accel_ch = ctx_buf;

	free(accel_ch->batch_pool_base);
	spdk_put_io_channel(accel_ch->engine_ch);
	free(accel_ch->task_pool_base);
}

struct spdk_io_channel *
spdk_accel_engine_get_io_channel(void)
{
	return spdk_get_io_channel(&spdk_accel_module_list);
}

static void
accel_engine_module_initialize(void)
{
	struct spdk_accel_module_if *accel_engine_module;

	TAILQ_FOREACH(accel_engine_module, &spdk_accel_module_list, tailq) {
		accel_engine_module->module_init();
	}
}

int
spdk_accel_engine_initialize(void)
{
	SPDK_NOTICELOG("Accel engine initialized to use software engine.\n");
	accel_engine_module_initialize();

	/*
	 * We need a unique identifier for the accel engine framework, so use the
	 *  spdk_accel_module_list address for this purpose.
	 */
	spdk_io_device_register(&spdk_accel_module_list, accel_engine_create_cb, accel_engine_destroy_cb,
				sizeof(struct accel_io_channel), "accel_module");

	return 0;
}

static void
accel_engine_module_finish_cb(void)
{
	spdk_accel_fini_cb cb_fn = g_fini_cb_fn;

	cb_fn(g_fini_cb_arg);
	g_fini_cb_fn = NULL;
	g_fini_cb_arg = NULL;
}

void
spdk_accel_write_config_json(struct spdk_json_write_ctx *w)
{
	struct spdk_accel_module_if *accel_engine_module;

	/*
	 * The accel fw has no config, there may be some in
	 * the engines/modules though.
	 */
	spdk_json_write_array_begin(w);
	TAILQ_FOREACH(accel_engine_module, &spdk_accel_module_list, tailq) {
		if (accel_engine_module->write_config_json) {
			accel_engine_module->write_config_json(w);
		}
	}
	spdk_json_write_array_end(w);
}

void
spdk_accel_engine_module_finish(void)
{
	if (!g_accel_engine_module) {
		g_accel_engine_module = TAILQ_FIRST(&spdk_accel_module_list);
	} else {
		g_accel_engine_module = TAILQ_NEXT(g_accel_engine_module, tailq);
	}

	if (!g_accel_engine_module) {
		accel_engine_module_finish_cb();
		return;
	}

	if (g_accel_engine_module->module_fini) {
		spdk_thread_send_msg(spdk_get_thread(), g_accel_engine_module->module_fini, NULL);
	} else {
		spdk_accel_engine_module_finish();
	}
}

void
spdk_accel_engine_finish(spdk_accel_fini_cb cb_fn, void *cb_arg)
{
	assert(cb_fn != NULL);

	g_fini_cb_fn = cb_fn;
	g_fini_cb_arg = cb_arg;

	spdk_io_device_unregister(&spdk_accel_module_list, NULL);
	spdk_accel_engine_module_finish();
}

/*
 * The SW Accelerator module is "built in" here (rest of file)
 */
static uint64_t
sw_accel_get_capabilities(void)
{
	/* No HW acceleration capabilities. */
	return 0;
}

static void
_sw_accel_dualcast(void *dst1, void *dst2, void *src, uint64_t nbytes)
{
	memcpy(dst1, src, (size_t)nbytes);
	memcpy(dst2, src, (size_t)nbytes);
}

static void
_sw_accel_copy(void *dst, void *src, uint64_t nbytes)
{
	memcpy(dst, src, (size_t)nbytes);
}

static int
_sw_accel_compare(void *src1, void *src2, uint64_t nbytes)
{
	return memcmp(src1, src2, (size_t)nbytes);
}

static void
_sw_accel_fill(void *dst, uint8_t fill, uint64_t nbytes)
{
	memset(dst, fill, nbytes);
}

static void
_sw_accel_crc32c(uint32_t *dst, void *src, uint32_t seed, uint64_t nbytes)
{
	*dst = spdk_crc32c_update(src, nbytes, ~seed);
}

static void
_sw_accel_crc32cv(uint32_t *dst, struct iovec *iov, uint32_t iovcnt, uint32_t seed)
{
	uint32_t i, crc32c = ~seed;

	for (i = 0; i < iovcnt; i++) {
		assert(iov[i].iov_base != NULL);
		assert(iov[i].iov_len != 0);
		crc32c = spdk_crc32c_update(iov[i].iov_base, iov[i].iov_len, crc32c);
	}

	*dst = crc32c;
}

static struct spdk_io_channel *sw_accel_get_io_channel(void);

static uint32_t
sw_accel_batch_get_max(struct spdk_io_channel *ch)
{
	return MAX_BATCH_SIZE;
}

static struct spdk_accel_engine sw_accel_engine = {
	.get_capabilities	= sw_accel_get_capabilities,
	.get_io_channel		= sw_accel_get_io_channel,
	.batch_get_max		= sw_accel_batch_get_max,
};

static int
sw_accel_create_cb(void *io_device, void *ctx_buf)
{
	return 0;
}

static void
sw_accel_destroy_cb(void *io_device, void *ctx_buf)
{
}

static struct spdk_io_channel *sw_accel_get_io_channel(void)
{
	return spdk_get_io_channel(&sw_accel_engine);
}

static size_t
sw_accel_engine_get_ctx_size(void)
{
	return sizeof(struct spdk_accel_task);
}

static int
sw_accel_engine_init(void)
{
	accel_sw_register(&sw_accel_engine);
	spdk_io_device_register(&sw_accel_engine, sw_accel_create_cb, sw_accel_destroy_cb,
				0, "sw_accel_engine");

	return 0;
}

static void
sw_accel_engine_fini(void *ctxt)
{
	spdk_io_device_unregister(&sw_accel_engine, NULL);
	accel_sw_unregister();

	spdk_accel_engine_module_finish();
}

SPDK_LOG_REGISTER_COMPONENT(accel)

SPDK_ACCEL_MODULE_REGISTER(sw_accel_engine_init, sw_accel_engine_fini,
			   NULL, sw_accel_engine_get_ctx_size)