Adding upstream version 14.2.21.upstream/14.2.21upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1624 insertions, 0 deletions

diff --git a/src/spdk/lib/bdev/raid/bdev_raid.c b/src/spdk/lib/bdev/raid/bdev_raid.c
new file mode 100644
index 00000000..51fa94ec
--- /dev/null
+++ b/src/spdk/lib/bdev/raid/bdev_raid.c
@@ -0,0 +1,1624 @@
+/*-
+ *   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 "bdev_raid.h"
+#include "spdk/env.h"
+#include "spdk/io_channel.h"
+#include "spdk/conf.h"
+#include "spdk_internal/log.h"
+#include "spdk/string.h"
+#include "spdk/util.h"
+#include "spdk/json.h"
+#include "spdk/string.h"
+
+static bool g_shutdown_started = false;
+
+/* raid bdev config as read from config file */
+struct raid_config          g_spdk_raid_config = {
+	.raid_bdev_config_head = TAILQ_HEAD_INITIALIZER(g_spdk_raid_config.raid_bdev_config_head),
+};
+
+/*
+ * List of raid bdev in configured list, these raid bdevs are registered with
+ * bdev layer
+ */
+struct spdk_raid_configured_tailq       g_spdk_raid_bdev_configured_list;
+
+/* List of raid bdev in configuring list */
+struct spdk_raid_configuring_tailq      g_spdk_raid_bdev_configuring_list;
+
+/* List of all raid bdevs */
+struct spdk_raid_all_tailq              g_spdk_raid_bdev_list;
+
+/* List of all raid bdevs that are offline */
+struct spdk_raid_offline_tailq          g_spdk_raid_bdev_offline_list;
+
+/* Function declarations */
+static void   raid_bdev_examine(struct spdk_bdev *bdev);
+static int    raid_bdev_init(void);
+static void   raid_bdev_waitq_io_process(void *ctx);
+static void   raid_bdev_deconfigure(struct raid_bdev *raid_bdev);
+
+
+/*
+ * brief:
+ * raid_bdev_create_cb function is a cb function for raid bdev which creates the
+ * hierarchy from raid bdev to base bdev io channels. It will be called per core
+ * params:
+ * io_device - pointer to raid bdev io device represented by raid_bdev
+ * ctx_buf - pointer to context buffer for raid bdev io channel
+ * returns:
+ * 0 - success
+ * non zero - failure
+ */
+static int
+raid_bdev_create_cb(void *io_device, void *ctx_buf)
+{
+	struct raid_bdev            *raid_bdev = io_device;
+	struct raid_bdev_io_channel *raid_ch = ctx_buf;
+
+	SPDK_DEBUGLOG(SPDK_LOG_BDEV_RAID, "raid_bdev_create_cb, %p\n", raid_ch);
+
+	assert(raid_bdev != NULL);
+	assert(raid_bdev->state == RAID_BDEV_STATE_ONLINE);
+
+	raid_ch->base_channel = calloc(raid_bdev->num_base_bdevs,
+				       sizeof(struct spdk_io_channel *));
+	if (!raid_ch->base_channel) {
+		SPDK_ERRLOG("Unable to allocate base bdevs io channel\n");
+		return -ENOMEM;
+	}
+	for (uint32_t i = 0; i < raid_bdev->num_base_bdevs; i++) {
+		/*
+		 * Get the spdk_io_channel for all the base bdevs. This is used during
+		 * split logic to send the respective child bdev ios to respective base
+		 * bdev io channel.
+		 */
+		raid_ch->base_channel[i] = spdk_bdev_get_io_channel(
+						   raid_bdev->base_bdev_info[i].desc);
+		if (!raid_ch->base_channel[i]) {
+			for (uint32_t j = 0; j < i; j++) {
+				spdk_put_io_channel(raid_ch->base_channel[j]);
+			}
+			free(raid_ch->base_channel);
+			SPDK_ERRLOG("Unable to create io channel for base bdev\n");
+			return -ENOMEM;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * brief:
+ * raid_bdev_destroy_cb function is a cb function for raid bdev which deletes the
+ * hierarchy from raid bdev to base bdev io channels. It will be called per core
+ * params:
+ * io_device - pointer to raid bdev io device represented by raid_bdev
+ * ctx_buf - pointer to context buffer for raid bdev io channel
+ * returns:
+ * none
+ */
+static void
+raid_bdev_destroy_cb(void *io_device, void *ctx_buf)
+{
+	struct raid_bdev_io_channel *raid_ch = ctx_buf;
+	struct raid_bdev            *raid_bdev = io_device;
+
+	SPDK_DEBUGLOG(SPDK_LOG_BDEV_RAID, "raid_bdev_destroy_cb\n");
+
+	assert(raid_bdev != NULL);
+	assert(raid_ch != NULL);
+	assert(raid_ch->base_channel);
+	for (uint32_t i = 0; i < raid_bdev->num_base_bdevs; i++) {
+		/* Free base bdev channels */
+		assert(raid_ch->base_channel[i] != NULL);
+		spdk_put_io_channel(raid_ch->base_channel[i]);
+		raid_ch->base_channel[i] = NULL;
+	}
+	free(raid_ch->base_channel);
+	raid_ch->base_channel = NULL;
+}
+
+/*
+ * brief:
+ * raid_bdev_cleanup is used to cleanup and free raid_bdev related data
+ * structures.
+ * params:
+ * raid_bdev - pointer to raid_bdev
+ * returns:
+ * none
+ */
+void
+raid_bdev_cleanup(struct raid_bdev *raid_bdev)
+{
+	SPDK_DEBUGLOG(SPDK_LOG_BDEV_RAID, "raid_bdev_cleanup, %p name %s, state %u, config %p\n",
+		      raid_bdev,
+		      raid_bdev->bdev.name, raid_bdev->state, raid_bdev->config);
+	if (raid_bdev->state == RAID_BDEV_STATE_CONFIGURING) {
+		TAILQ_REMOVE(&g_spdk_raid_bdev_configuring_list, raid_bdev, state_link);
+	} else if (raid_bdev->state == RAID_BDEV_STATE_OFFLINE) {
+		TAILQ_REMOVE(&g_spdk_raid_bdev_offline_list, raid_bdev, state_link);
+	} else {
+		assert(0);
+	}
+	TAILQ_REMOVE(&g_spdk_raid_bdev_list, raid_bdev, global_link);
+	free(raid_bdev->bdev.name);
+	raid_bdev->bdev.name = NULL;
+	assert(raid_bdev->base_bdev_info);
+	free(raid_bdev->base_bdev_info);
+	raid_bdev->base_bdev_info = NULL;
+	if (raid_bdev->config) {
+		raid_bdev->config->raid_bdev = NULL;
+	}
+	free(raid_bdev);
+}
+
+/*
+ * brief:
+ * free resource of base bdev for raid bdev
+ * params:
+ * raid_bdev - pointer to raid bdev
+ * base_bdev_slot - position to base bdev in raid bdev
+ * returns:
+ * 0 - success
+ * non zero - failure
+ */
+void
+raid_bdev_free_base_bdev_resource(struct raid_bdev *raid_bdev, uint32_t base_bdev_slot)
+{
+	struct raid_base_bdev_info *info;
+
+	info = &raid_bdev->base_bdev_info[base_bdev_slot];
+
+	spdk_bdev_module_release_bdev(info->bdev);
+	spdk_bdev_close(info->desc);
+	info->desc = NULL;
+	info->bdev = NULL;
+
+	assert(raid_bdev->num_base_bdevs_discovered);
+	raid_bdev->num_base_bdevs_discovered--;
+}
+
+/*
+ * brief:
+ * raid_bdev_destruct is the destruct function table pointer for raid bdev
+ * params:
+ * ctxt - pointer to raid_bdev
+ * returns:
+ * 0 - success
+ * non zero - failure
+ */
+static int
+raid_bdev_destruct(void *ctxt)
+{
+	struct raid_bdev *raid_bdev = ctxt;
+
+	SPDK_DEBUGLOG(SPDK_LOG_BDEV_RAID, "raid_bdev_destruct\n");
+
+	raid_bdev->destruct_called = true;
+	for (uint16_t i = 0; i < raid_bdev->num_base_bdevs; i++) {
+		/*
+		 * Close all base bdev descriptors for which call has come from below
+		 * layers.  Also close the descriptors if we have started shutdown.
+		 */
+		if (g_shutdown_started ||
+		    ((raid_bdev->base_bdev_info[i].remove_scheduled == true) &&
+		     (raid_bdev->base_bdev_info[i].bdev != NULL))) {
+			raid_bdev_free_base_bdev_resource(raid_bdev, i);
+		}
+	}
+
+	if (g_shutdown_started) {
+		TAILQ_REMOVE(&g_spdk_raid_bdev_configured_list, raid_bdev, state_link);
+		raid_bdev->state = RAID_BDEV_STATE_OFFLINE;
+		TAILQ_INSERT_TAIL(&g_spdk_raid_bdev_offline_list, raid_bdev, state_link);
+		spdk_io_device_unregister(raid_bdev, NULL);
+	}
+
+	if (raid_bdev->num_base_bdevs_discovered == 0) {
+		/* Free raid_bdev when there are no base bdevs left */
+		SPDK_DEBUGLOG(SPDK_LOG_BDEV_RAID, "raid bdev base bdevs is 0, going to free all in destruct\n");
+		raid_bdev_cleanup(raid_bdev);
+	}
+
+	return 0;
+}
+
+/*
+ * brief:
+ * raid_bdev_io_completion function is called by lower layers to notify raid
+ * module that particular bdev_io is completed.
+ * params:
+ * bdev_io - pointer to bdev io submitted to lower layers, like child io
+ * success - bdev_io status
+ * cb_arg - function callback context, like parent io pointer
+ * returns:
+ * none
+ */
+static void
+raid_bdev_io_completion(struct spdk_bdev_io *bdev_io, bool success, void *cb_arg)
+{
+	struct spdk_bdev_io         *parent_io = cb_arg;
+
+	spdk_bdev_free_io(bdev_io);
+
+	if (success) {
+		spdk_bdev_io_complete(parent_io, SPDK_BDEV_IO_STATUS_SUCCESS);
+	} else {
+		spdk_bdev_io_complete(parent_io, SPDK_BDEV_IO_STATUS_FAILED);
+	}
+}
+
+/*
+ * brief:
+ * raid_bdev_submit_rw_request function is used to submit I/O to the correct
+ * member disk
+ * params:
+ * bdev_io - parent bdev io
+ * start_strip - start strip number of this io
+ * returns:
+ * 0 - success
+ * non zero - failure
+ */
+static int
+raid_bdev_submit_rw_request(struct spdk_bdev_io *bdev_io, uint64_t start_strip)
+{
+	struct raid_bdev_io		*raid_io = (struct raid_bdev_io *)bdev_io->driver_ctx;
+	struct raid_bdev_io_channel	*raid_ch = spdk_io_channel_get_ctx(raid_io->ch);
+	struct raid_bdev		*raid_bdev = (struct raid_bdev *)bdev_io->bdev->ctxt;
+	uint64_t			pd_strip;
+	uint32_t			offset_in_strip;
+	uint64_t			pd_lba;
+	uint64_t			pd_blocks;
+	uint32_t			pd_idx;
+	int				ret = 0;
+
+	pd_strip = start_strip / raid_bdev->num_base_bdevs;
+	pd_idx = start_strip % raid_bdev->num_base_bdevs;
+	offset_in_strip = bdev_io->u.bdev.offset_blocks & (raid_bdev->strip_size - 1);
+	pd_lba = (pd_strip << raid_bdev->strip_size_shift) + offset_in_strip;
+	pd_blocks = bdev_io->u.bdev.num_blocks;
+	if (raid_bdev->base_bdev_info[pd_idx].desc == NULL) {
+		SPDK_ERRLOG("base bdev desc null for pd_idx %u\n", pd_idx);
+		assert(0);
+	}
+
+	/*
+	 * Submit child io to bdev layer with using base bdev descriptors, base
+	 * bdev lba, base bdev child io length in blocks, buffer, completion
+	 * function and function callback context
+	 */
+	if (bdev_io->type == SPDK_BDEV_IO_TYPE_READ) {
+		ret = spdk_bdev_readv_blocks(raid_bdev->base_bdev_info[pd_idx].desc,
+					     raid_ch->base_channel[pd_idx],
+					     bdev_io->u.bdev.iovs, bdev_io->u.bdev.iovcnt,
+					     pd_lba, pd_blocks, raid_bdev_io_completion,
+					     bdev_io);
+	} else if (bdev_io->type == SPDK_BDEV_IO_TYPE_WRITE) {
+		ret = spdk_bdev_writev_blocks(raid_bdev->base_bdev_info[pd_idx].desc,
+					      raid_ch->base_channel[pd_idx],
+					      bdev_io->u.bdev.iovs, bdev_io->u.bdev.iovcnt,
+					      pd_lba, pd_blocks, raid_bdev_io_completion,
+					      bdev_io);
+	} else {
+		SPDK_ERRLOG("Recvd not supported io type %u\n", bdev_io->type);
+		assert(0);
+	}
+
+	return ret;
+}
+
+/*
+ * brief:
+ * get_curr_base_bdev_index function calculates the base bdev index
+ * params:
+ * raid_bdev - pointer to pooled bdev
+ * raid_io - pointer to parent io context
+ * returns:
+ * base bdev index
+ */
+static uint8_t
+get_curr_base_bdev_index(struct raid_bdev *raid_bdev, struct raid_bdev_io *raid_io)
+{
+	struct spdk_bdev_io	*bdev_io;
+	uint64_t		start_strip;
+
+	bdev_io = SPDK_CONTAINEROF(raid_io, struct spdk_bdev_io, driver_ctx);
+	start_strip = bdev_io->u.bdev.offset_blocks >> raid_bdev->strip_size_shift;
+
+	return (start_strip % raid_bdev->num_base_bdevs);
+}
+
+/*
+ * brief:
+ * raid_bdev_io_submit_fail_process function processes the IO which failed to submit.
+ * It will try to queue the IOs after storing the context to bdev wait queue logic.
+ * params:
+ * bdev_io - pointer to bdev_io
+ * raid_io - pointer to raid bdev io
+ * ret - return code
+ * returns:
+ * none
+ */
+static void
+raid_bdev_io_submit_fail_process(struct raid_bdev *raid_bdev, struct spdk_bdev_io *bdev_io,
+				 struct raid_bdev_io *raid_io, int ret)
+{
+	struct   raid_bdev_io_channel *raid_ch;
+	uint8_t pd_idx;
+
+	if (ret != -ENOMEM) {
+		spdk_bdev_io_complete(bdev_io, SPDK_BDEV_IO_STATUS_FAILED);
+	} else {
+		/* Queue the IO to bdev layer wait queue */
+		pd_idx = get_curr_base_bdev_index(raid_bdev, raid_io);
+		raid_io->waitq_entry.bdev = raid_bdev->base_bdev_info[pd_idx].bdev;
+		raid_io->waitq_entry.cb_fn = raid_bdev_waitq_io_process;
+		raid_io->waitq_entry.cb_arg = raid_io;
+		raid_ch = spdk_io_channel_get_ctx(raid_io->ch);
+		if (spdk_bdev_queue_io_wait(raid_bdev->base_bdev_info[pd_idx].bdev,
+					    raid_ch->base_channel[pd_idx],
+					    &raid_io->waitq_entry) != 0) {
+			SPDK_ERRLOG("bdev io waitq error, it should not happen\n");
+			assert(0);
+			spdk_bdev_io_complete(bdev_io, SPDK_BDEV_IO_STATUS_FAILED);
+		}
+	}
+}
+
+/*
+ * brief:
+ * raid_bdev_waitq_io_process function is the callback function
+ * registered by raid bdev module to bdev when bdev_io was unavailable.
+ * params:
+ * ctx - pointer to raid_bdev_io
+ * returns:
+ * none
+ */
+static void
+raid_bdev_waitq_io_process(void *ctx)
+{
+	struct   raid_bdev_io         *raid_io = ctx;
+	struct   spdk_bdev_io         *bdev_io;
+	struct   raid_bdev            *raid_bdev;
+	int                           ret;
+	uint64_t                      start_strip;
+
+	bdev_io = SPDK_CONTAINEROF(raid_io, struct spdk_bdev_io, driver_ctx);
+	/*
+	 * Try to submit childs of parent bdev io. If failed due to resource
+	 * crunch then break the loop and don't try to process other queued IOs.
+	 */
+	raid_bdev = (struct raid_bdev *)bdev_io->bdev->ctxt;
+	start_strip = bdev_io->u.bdev.offset_blocks >> raid_bdev->strip_size_shift;
+	ret = raid_bdev_submit_rw_request(bdev_io, start_strip);
+	if (ret != 0) {
+		raid_bdev_io_submit_fail_process(raid_bdev, bdev_io, raid_io, ret);
+	}
+}
+
+/*
+ * brief:
+ * raid_bdev_start_rw_request function is the submit_request function for
+ * read/write requests
+ * params:
+ * ch - pointer to raid bdev io channel
+ * bdev_io - pointer to parent bdev_io on raid bdev device
+ * returns:
+ * none
+ */
+static void
+raid_bdev_start_rw_request(struct spdk_io_channel *ch, struct spdk_bdev_io *bdev_io)
+{
+	struct raid_bdev_io		*raid_io;
+	struct raid_bdev		*raid_bdev;
+	uint64_t			start_strip = 0;
+	uint64_t			end_strip = 0;
+	int				ret;
+
+	raid_bdev = (struct raid_bdev *)bdev_io->bdev->ctxt;
+	raid_io = (struct raid_bdev_io *)bdev_io->driver_ctx;
+	raid_io->ch = ch;
+	start_strip = bdev_io->u.bdev.offset_blocks >> raid_bdev->strip_size_shift;
+	end_strip = (bdev_io->u.bdev.offset_blocks + bdev_io->u.bdev.num_blocks - 1) >>
+		    raid_bdev->strip_size_shift;
+	if (start_strip != end_strip && raid_bdev->num_base_bdevs > 1) {
+		assert(false);
+		SPDK_ERRLOG("I/O spans strip boundary!\n");
+		spdk_bdev_io_complete(bdev_io, SPDK_BDEV_IO_STATUS_FAILED);
+		return;
+	}
+	ret = raid_bdev_submit_rw_request(bdev_io, start_strip);
+	if (ret != 0) {
+		raid_bdev_io_submit_fail_process(raid_bdev, bdev_io, raid_io, ret);
+	}
+}
+
+/*
+ * brief:
+ * raid_bdev_reset_completion is the completion callback for member disk resets
+ * params:
+ * bdev_io - pointer to member disk reset bdev_io
+ * success - true if reset was successful, false if unsuccessful
+ * cb_arg - callback argument (parent reset bdev_io)
+ * returns:
+ * none
+ */
+static void
+raid_bdev_reset_completion(struct spdk_bdev_io *bdev_io, bool success, void *cb_arg)
+{
+	struct spdk_bdev_io *parent_io = cb_arg;
+	struct raid_bdev *raid_bdev = (struct raid_bdev *)parent_io->bdev->ctxt;
+	struct raid_bdev_io *raid_io = (struct raid_bdev_io *)parent_io->driver_ctx;
+
+	spdk_bdev_free_io(bdev_io);
+
+	if (!success) {
+		raid_io->base_bdev_reset_status = SPDK_BDEV_IO_STATUS_FAILED;
+	}
+
+	raid_io->base_bdev_reset_completed++;
+	if (raid_io->base_bdev_reset_completed == raid_bdev->num_base_bdevs) {
+		spdk_bdev_io_complete(parent_io, raid_io->base_bdev_reset_status);
+	}
+}
+
+/*
+ * brief:
+ * _raid_bdev_submit_reset_request_next function submits the next batch of reset requests
+ * to member disks; it will submit as many as possible unless a reset fails with -ENOMEM, in
+ * which case it will queue it for later submission
+ * params:
+ * bdev_io - pointer to parent bdev_io on raid bdev device
+ * returns:
+ * none
+ */
+static void
+_raid_bdev_submit_reset_request_next(void *_bdev_io)
+{
+	struct spdk_bdev_io		*bdev_io = _bdev_io;
+	struct raid_bdev_io		*raid_io;
+	struct raid_bdev		*raid_bdev;
+	struct raid_bdev_io_channel	*raid_ch;
+	int				ret;
+	uint8_t				i;
+
+	raid_bdev = (struct raid_bdev *)bdev_io->bdev->ctxt;
+	raid_io = (struct raid_bdev_io *)bdev_io->driver_ctx;
+	raid_ch = spdk_io_channel_get_ctx(raid_io->ch);
+
+	while (raid_io->base_bdev_reset_submitted < raid_bdev->num_base_bdevs) {
+		i = raid_io->base_bdev_reset_submitted;
+		ret = spdk_bdev_reset(raid_bdev->base_bdev_info[i].desc,
+				      raid_ch->base_channel[i],
+				      raid_bdev_reset_completion, bdev_io);
+		if (ret == 0) {
+			raid_io->base_bdev_reset_submitted++;
+		} else if (ret == -ENOMEM) {
+			raid_io->waitq_entry.bdev = raid_bdev->base_bdev_info[i].bdev;
+			raid_io->waitq_entry.cb_fn = _raid_bdev_submit_reset_request_next;
+			raid_io->waitq_entry.cb_arg = bdev_io;
+			spdk_bdev_queue_io_wait(raid_bdev->base_bdev_info[i].bdev,
+						raid_ch->base_channel[i],
+						&raid_io->waitq_entry);
+			return;
+		} else {
+			assert(false);
+			spdk_bdev_io_complete(bdev_io, SPDK_BDEV_IO_STATUS_FAILED);
+			return;
+		}
+	}
+}
+
+/*
+ * brief:
+ * _raid_bdev_submit_reset_request function is the submit_request function for
+ * reset requests
+ * params:
+ * ch - pointer to raid bdev io channel
+ * bdev_io - pointer to parent bdev_io on raid bdev device
+ * returns:
+ * none
+ */
+static void
+_raid_bdev_submit_reset_request(struct spdk_io_channel *ch, struct spdk_bdev_io *bdev_io)
+{
+	struct raid_bdev_io		*raid_io;
+
+	raid_io = (struct raid_bdev_io *)bdev_io->driver_ctx;
+	raid_io->ch = ch;
+	raid_io->base_bdev_reset_submitted = 0;
+	raid_io->base_bdev_reset_completed = 0;
+	raid_io->base_bdev_reset_status = SPDK_BDEV_IO_STATUS_SUCCESS;
+	_raid_bdev_submit_reset_request_next(bdev_io);
+}
+
+/*
+ * brief:
+ * raid_bdev_submit_request function is the submit_request function pointer of
+ * raid bdev function table. This is used to submit the io on raid_bdev to below
+ * layers.
+ * params:
+ * ch - pointer to raid bdev io channel
+ * bdev_io - pointer to parent bdev_io on raid bdev device
+ * returns:
+ * none
+ */
+static void
+raid_bdev_submit_request(struct spdk_io_channel *ch, struct spdk_bdev_io *bdev_io)
+{
+	switch (bdev_io->type) {
+	case SPDK_BDEV_IO_TYPE_READ:
+		if (bdev_io->u.bdev.iovs[0].iov_base == NULL) {
+			spdk_bdev_io_get_buf(bdev_io, raid_bdev_start_rw_request,
+					     bdev_io->u.bdev.num_blocks * bdev_io->bdev->blocklen);
+		} else {
+			/* Just call it directly if iov_base is already populated. */
+			raid_bdev_start_rw_request(ch, bdev_io);
+		}
+		break;
+	case SPDK_BDEV_IO_TYPE_WRITE:
+		raid_bdev_start_rw_request(ch, bdev_io);
+		break;
+
+	case SPDK_BDEV_IO_TYPE_FLUSH:
+		// TODO: support flush if requirement comes
+		spdk_bdev_io_complete(bdev_io, SPDK_BDEV_IO_STATUS_SUCCESS);
+		break;
+
+	case SPDK_BDEV_IO_TYPE_RESET:
+		_raid_bdev_submit_reset_request(ch, bdev_io);
+		break;
+
+	default:
+		SPDK_ERRLOG("submit request, invalid io type %u\n", bdev_io->type);
+		spdk_bdev_io_complete(bdev_io, SPDK_BDEV_IO_STATUS_FAILED);
+		break;
+	}
+
+}
+
+/*
+ * brief:
+ * raid_bdev_io_type_supported is the io_supported function for bdev function
+ * table which returns whether the particular io type is supported or not by
+ * raid bdev module
+ * params:
+ * ctx - pointer to raid bdev context
+ * type - io type
+ * returns:
+ * true - io_type is supported
+ * false - io_type is not supported
+ */
+static bool
+raid_bdev_io_type_supported(void *ctx, enum spdk_bdev_io_type io_type)
+{
+	switch (io_type) {
+	case SPDK_BDEV_IO_TYPE_READ:
+	case SPDK_BDEV_IO_TYPE_WRITE:
+	case SPDK_BDEV_IO_TYPE_FLUSH:
+	case SPDK_BDEV_IO_TYPE_RESET:
+		return true;
+	default:
+		return false;
+	}
+
+	return false;
+}
+
+/*
+ * brief:
+ * raid_bdev_get_io_channel is the get_io_channel function table pointer for
+ * raid bdev. This is used to return the io channel for this raid bdev
+ * params:
+ * ctxt - pointer to raid_bdev
+ * returns:
+ * pointer to io channel for raid bdev
+ */
+static struct spdk_io_channel *
+raid_bdev_get_io_channel(void *ctxt)
+{
+	struct raid_bdev *raid_bdev = ctxt;
+
+	return spdk_get_io_channel(raid_bdev);
+}
+
+/*
+ * brief:
+ * raid_bdev_dump_info_json is the function table pointer for raid bdev
+ * params:
+ * ctx - pointer to raid_bdev
+ * w - pointer to json context
+ * returns:
+ * 0 - success
+ * non zero - failure
+ */
+static int
+raid_bdev_dump_info_json(void *ctx, struct spdk_json_write_ctx *w)
+{
+	struct raid_bdev *raid_bdev = ctx;
+
+	SPDK_DEBUGLOG(SPDK_LOG_BDEV_RAID, "raid_bdev_dump_config_json\n");
+	assert(raid_bdev != NULL);
+
+	/* Dump the raid bdev configuration related information */
+	spdk_json_write_name(w, "raid");
+	spdk_json_write_object_begin(w);
+	spdk_json_write_named_uint32(w, "strip_size", raid_bdev->strip_size);
+	spdk_json_write_named_uint32(w, "state", raid_bdev->state);
+	spdk_json_write_named_uint32(w, "raid_level", raid_bdev->raid_level);
+	spdk_json_write_named_uint32(w, "destruct_called", raid_bdev->destruct_called);
+	spdk_json_write_named_uint32(w, "num_base_bdevs", raid_bdev->num_base_bdevs);
+	spdk_json_write_named_uint32(w, "num_base_bdevs_discovered", raid_bdev->num_base_bdevs_discovered);
+	spdk_json_write_name(w, "base_bdevs_list");
+	spdk_json_write_array_begin(w);
+	for (uint16_t i = 0; i < raid_bdev->num_base_bdevs; i++) {
+		if (raid_bdev->base_bdev_info[i].bdev) {
+			spdk_json_write_string(w, raid_bdev->base_bdev_info[i].bdev->name);
+		} else {
+			spdk_json_write_null(w);
+		}
+	}
+	spdk_json_write_array_end(w);
+	spdk_json_write_object_end(w);
+
+	return 0;
+}
+
+/*
+ * brief:
+ * raid_bdev_write_config_json is the function table pointer for raid bdev
+ * params:
+ * bdev - pointer to spdk_bdev
+ * w - pointer to json context
+ * returns:
+ * none
+ */
+static void
+raid_bdev_write_config_json(struct spdk_bdev *bdev, struct spdk_json_write_ctx *w)
+{
+	struct raid_bdev *raid_bdev = bdev->ctxt;
+	struct spdk_bdev *base;
+	uint16_t i;
+
+	spdk_json_write_object_begin(w);
+
+	spdk_json_write_named_string(w, "method", "construct_raid_bdev");
+
+	spdk_json_write_named_object_begin(w, "params");
+	spdk_json_write_named_string(w, "name", bdev->name);
+	spdk_json_write_named_uint32(w, "strip_size", raid_bdev->strip_size);
+	spdk_json_write_named_uint32(w, "raid_level", raid_bdev->raid_level);
+
+	spdk_json_write_named_array_begin(w, "base_bdevs");
+	for (i = 0; i < raid_bdev->num_base_bdevs; i++) {
+		base = raid_bdev->base_bdev_info[i].bdev;
+		if (base) {
+			spdk_json_write_string(w, base->name);
+		}
+	}
+	spdk_json_write_array_end(w);
+	spdk_json_write_object_end(w);
+
+	spdk_json_write_object_end(w);
+}
+
+/* g_raid_bdev_fn_table is the function table for raid bdev */
+static const struct spdk_bdev_fn_table g_raid_bdev_fn_table = {
+	.destruct		= raid_bdev_destruct,
+	.submit_request		= raid_bdev_submit_request,
+	.io_type_supported	= raid_bdev_io_type_supported,
+	.get_io_channel		= raid_bdev_get_io_channel,
+	.dump_info_json		= raid_bdev_dump_info_json,
+	.write_config_json	= raid_bdev_write_config_json,
+};
+
+/*
+ * brief:
+ * raid_bdev_config_cleanup function is used to free memory for one raid_bdev in configuration
+ * params:
+ * raid_cfg - pointer to raid_bdev_config structure
+ * returns:
+ * none
+ */
+void
+raid_bdev_config_cleanup(struct raid_bdev_config *raid_cfg)
+{
+	uint32_t i;
+
+	TAILQ_REMOVE(&g_spdk_raid_config.raid_bdev_config_head, raid_cfg, link);
+	g_spdk_raid_config.total_raid_bdev--;
+
+	if (raid_cfg->base_bdev) {
+		for (i = 0; i < raid_cfg->num_base_bdevs; i++) {
+			free(raid_cfg->base_bdev[i].name);
+		}
+		free(raid_cfg->base_bdev);
+	}
+	free(raid_cfg->name);
+	free(raid_cfg);
+}
+
+/*
+ * brief:
+ * raid_bdev_free is the raid bdev function table function pointer. This is
+ * called on bdev free path
+ * params:
+ * none
+ * returns:
+ * none
+ */
+static void
+raid_bdev_free(void)
+{
+	struct raid_bdev_config *raid_cfg, *tmp;
+
+	SPDK_DEBUGLOG(SPDK_LOG_BDEV_RAID, "raid_bdev_free\n");
+	TAILQ_FOREACH_SAFE(raid_cfg, &g_spdk_raid_config.raid_bdev_config_head, link, tmp) {
+		raid_bdev_config_cleanup(raid_cfg);
+	}
+}
+
+/* brief
+ * raid_bdev_config_find_by_name is a helper function to find raid bdev config
+ * by name as key.
+ *
+ * params:
+ * raid_name - name for raid bdev.
+ */
+struct raid_bdev_config *
+raid_bdev_config_find_by_name(const char *raid_name)
+{
+	struct raid_bdev_config *raid_cfg;
+
+	TAILQ_FOREACH(raid_cfg, &g_spdk_raid_config.raid_bdev_config_head, link) {
+		if (!strcmp(raid_cfg->name, raid_name)) {
+			return raid_cfg;
+		}
+	}
+
+	return raid_cfg;
+}
+
+/*
+ * brief
+ * raid_bdev_config_add function adds config for newly created raid bdev.
+ *
+ * params:
+ * raid_name - name for raid bdev.
+ * strip_size - strip size in KB
+ * num_base_bdevs - number of base bdevs.
+ * raid_level - raid level, only raid level 0 is supported.
+ * _raid_cfg - Pointer to newly added configuration
+ */
+int
+raid_bdev_config_add(const char *raid_name, int strip_size, int num_base_bdevs,
+		     int raid_level, struct raid_bdev_config **_raid_cfg)
+{
+	struct raid_bdev_config *raid_cfg;
+
+	raid_cfg = raid_bdev_config_find_by_name(raid_name);
+	if (raid_cfg != NULL) {
+		SPDK_ERRLOG("Duplicate raid bdev name found in config file %s\n",
+			    raid_name);
+		return -EEXIST;
+	}
+
+	if (spdk_u32_is_pow2(strip_size) == false) {
+		SPDK_ERRLOG("Invalid strip size %d\n", strip_size);
+		return -EINVAL;
+	}
+
+	if (num_base_bdevs <= 0) {
+		SPDK_ERRLOG("Invalid base device count %d\n", num_base_bdevs);
+		return -EINVAL;
+	}
+
+	if (raid_level != 0) {
+		SPDK_ERRLOG("invalid raid level %d, only raid level 0 is supported\n",
+			    raid_level);
+		return -EINVAL;
+	}
+
+	raid_cfg = calloc(1, sizeof(*raid_cfg));
+	if (raid_cfg == NULL) {
+		SPDK_ERRLOG("unable to allocate memory\n");
+		return -ENOMEM;
+	}
+
+	raid_cfg->name = strdup(raid_name);
+	if (!raid_cfg->name) {
+		free(raid_cfg);
+		SPDK_ERRLOG("unable to allocate memory\n");
+		return -ENOMEM;
+	}
+	raid_cfg->strip_size = strip_size;
+	raid_cfg->num_base_bdevs = num_base_bdevs;
+	raid_cfg->raid_level = raid_level;
+
+	raid_cfg->base_bdev = calloc(num_base_bdevs, sizeof(*raid_cfg->base_bdev));
+	if (raid_cfg->base_bdev == NULL) {
+		free(raid_cfg->name);
+		free(raid_cfg);
+		SPDK_ERRLOG("unable to allocate memory\n");
+		return -ENOMEM;
+	}
+
+	TAILQ_INSERT_TAIL(&g_spdk_raid_config.raid_bdev_config_head, raid_cfg, link);
+	g_spdk_raid_config.total_raid_bdev++;
+
+	*_raid_cfg = raid_cfg;
+	return 0;
+}
+
+/*
+ * brief:
+ * raid_bdev_config_add_base_bdev function add base bdev to raid bdev config.
+ *
+ * params:
+ * raid_cfg - pointer to raid bdev configuration
+ * base_bdev_name - name of base bdev
+ * slot - Position to add base bdev
+ */
+int
+raid_bdev_config_add_base_bdev(struct raid_bdev_config *raid_cfg, const char *base_bdev_name,
+			       uint32_t slot)
+{
+	uint32_t i;
+	struct raid_bdev_config *tmp;
+
+	if (slot >= raid_cfg->num_base_bdevs) {
+		return -EINVAL;
+	}
+
+	TAILQ_FOREACH(tmp, &g_spdk_raid_config.raid_bdev_config_head, link) {
+		for (i = 0; i < tmp->num_base_bdevs; i++) {
+			if (tmp->base_bdev[i].name != NULL) {
+				if (!strcmp(tmp->base_bdev[i].name, base_bdev_name)) {
+					SPDK_ERRLOG("duplicate base bdev name %s mentioned\n",
+						    base_bdev_name);
+					return -EEXIST;
+				}
+			}
+		}
+	}
+
+	raid_cfg->base_bdev[slot].name = strdup(base_bdev_name);
+	if (raid_cfg->base_bdev[slot].name == NULL) {
+		SPDK_ERRLOG("unable to allocate memory\n");
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+/*
+ * brief:
+ * raid_bdev_parse_raid is used to parse the raid bdev from config file based on
+ * pre-defined raid bdev format in config file.
+ * Format of config file:
+ *   [RAID1]
+ *   Name raid1
+ *   StripSize 64
+ *   NumDevices 2
+ *   RaidLevel 0
+ *   Devices Nvme0n1 Nvme1n1
+ *
+ *   [RAID2]
+ *   Name raid2
+ *   StripSize 64
+ *   NumDevices 3
+ *   RaidLevel 0
+ *   Devices Nvme2n1 Nvme3n1 Nvme4n1
+ *
+ * params:
+ * conf_section - pointer to config section
+ * returns:
+ * 0 - success
+ * non zero - failure
+ */
+static int
+raid_bdev_parse_raid(struct spdk_conf_section *conf_section)
+{
+	const char *raid_name;
+	int strip_size;
+	int i, num_base_bdevs;
+	int raid_level;
+	const char *base_bdev_name;
+	struct raid_bdev_config *raid_cfg;
+	int rc;
+
+	raid_name = spdk_conf_section_get_val(conf_section, "Name");
+	if (raid_name == NULL) {
+		SPDK_ERRLOG("raid_name %s is null\n", raid_name);
+		return -EINVAL;
+	}
+
+	strip_size = spdk_conf_section_get_intval(conf_section, "StripSize");
+	num_base_bdevs = spdk_conf_section_get_intval(conf_section, "NumDevices");
+	raid_level = spdk_conf_section_get_intval(conf_section, "RaidLevel");
+
+	SPDK_DEBUGLOG(SPDK_LOG_BDEV_RAID, "%s %d %d %d\n", raid_name, strip_size, num_base_bdevs,
+		      raid_level);
+
+	rc = raid_bdev_config_add(raid_name, strip_size, num_base_bdevs, raid_level,
+				  &raid_cfg);
+	if (rc != 0) {
+		SPDK_ERRLOG("Failed to add raid bdev config\n");
+		return rc;
+	}
+
+	for (i = 0; true; i++) {
+		base_bdev_name = spdk_conf_section_get_nmval(conf_section, "Devices", 0, i);
+		if (base_bdev_name == NULL) {
+			break;
+		}
+		if (i >= num_base_bdevs) {
+			raid_bdev_config_cleanup(raid_cfg);
+			SPDK_ERRLOG("Number of devices mentioned is more than count\n");
+			return -EINVAL;
+		}
+
+		rc = raid_bdev_config_add_base_bdev(raid_cfg, base_bdev_name, i);
+		if (rc != 0) {
+			raid_bdev_config_cleanup(raid_cfg);
+			SPDK_ERRLOG("Failed to add base bdev to raid bdev config\n");
+			return rc;
+		}
+	}
+
+	if (i != raid_cfg->num_base_bdevs) {
+		raid_bdev_config_cleanup(raid_cfg);
+		SPDK_ERRLOG("Number of devices mentioned is less than count\n");
+		return -EINVAL;
+	}
+
+	rc = raid_bdev_create(raid_cfg);
+	if (rc != 0) {
+		raid_bdev_config_cleanup(raid_cfg);
+		SPDK_ERRLOG("Failed to create raid bdev\n");
+		return rc;
+	}
+
+	rc = raid_bdev_add_base_devices(raid_cfg);
+	if (rc != 0) {
+		SPDK_ERRLOG("Failed to add any base bdev to raid bdev\n");
+		/* Config is not removed in this case. */
+	}
+
+	return 0;
+}
+
+/*
+ * brief:
+ * raid_bdev_parse_config is used to find the raid bdev config section and parse it
+ * Format of config file:
+ * params:
+ * none
+ * returns:
+ * 0 - success
+ * non zero - failure
+ */
+static int
+raid_bdev_parse_config(void)
+{
+	int                      ret;
+	struct spdk_conf_section *conf_section;
+
+	conf_section = spdk_conf_first_section(NULL);
+	while (conf_section != NULL) {
+		if (spdk_conf_section_match_prefix(conf_section, "RAID")) {
+			ret = raid_bdev_parse_raid(conf_section);
+			if (ret < 0) {
+				SPDK_ERRLOG("Unable to parse raid bdev section\n");
+				return ret;
+			}
+		}
+		conf_section = spdk_conf_next_section(conf_section);
+	}
+
+	return 0;
+}
+
+/*
+ * brief:
+ * raid_bdev_fini_start is called when bdev layer is starting the
+ * shutdown process
+ * params:
+ * none
+ * returns:
+ * none
+ */
+static void
+raid_bdev_fini_start(void)
+{
+	SPDK_DEBUGLOG(SPDK_LOG_BDEV_RAID, "raid_bdev_fini_start\n");
+	g_shutdown_started = true;
+}
+
+/*
+ * brief:
+ * raid_bdev_exit is called on raid bdev module exit time by bdev layer
+ * params:
+ * none
+ * returns:
+ * none
+ */
+static void
+raid_bdev_exit(void)
+{
+	SPDK_DEBUGLOG(SPDK_LOG_BDEV_RAID, "raid_bdev_exit\n");
+	raid_bdev_free();
+}
+
+/*
+ * brief:
+ * raid_bdev_get_ctx_size is used to return the context size of bdev_io for raid
+ * module
+ * params:
+ * none
+ * returns:
+ * size of spdk_bdev_io context for raid
+ */
+static int
+raid_bdev_get_ctx_size(void)
+{
+	SPDK_DEBUGLOG(SPDK_LOG_BDEV_RAID, "raid_bdev_get_ctx_size\n");
+	return sizeof(struct raid_bdev_io);
+}
+
+/*
+ * brief:
+ * raid_bdev_get_running_config is used to get the configuration options.
+ *
+ * params:
+ * fp - The pointer to a file that will be written to the configuration options.
+ * returns:
+ * none
+ */
+static void
+raid_bdev_get_running_config(FILE *fp)
+{
+	struct raid_bdev *raid_bdev;
+	struct spdk_bdev *base;
+	int index = 1;
+	uint16_t i;
+
+	TAILQ_FOREACH(raid_bdev, &g_spdk_raid_bdev_configured_list, state_link) {
+		fprintf(fp,
+			"\n"
+			"[RAID%d]\n"
+			"  Name %s\n"
+			"  StripSize %" PRIu32 "\n"
+			"  NumDevices %hu\n"
+			"  RaidLevel %hhu\n",
+			index, raid_bdev->bdev.name, raid_bdev->strip_size,
+			raid_bdev->num_base_bdevs, raid_bdev->raid_level);
+		fprintf(fp,
+			"  Devices ");
+		for (i = 0; i < raid_bdev->num_base_bdevs; i++) {
+			base = raid_bdev->base_bdev_info[i].bdev;
+			if (base) {
+				fprintf(fp,
+					"%s ",
+					base->name);
+			}
+		}
+		fprintf(fp,
+			"\n");
+		index++;
+	}
+}
+
+/*
+ * brief:
+ * raid_bdev_can_claim_bdev is the function to check if this base_bdev can be
+ * claimed by raid bdev or not.
+ * params:
+ * bdev_name - represents base bdev name
+ * _raid_cfg - pointer to raid bdev config parsed from config file
+ * base_bdev_slot - if bdev can be claimed, it represents the base_bdev correct
+ * slot. This field is only valid if return value of this function is true
+ * returns:
+ * true - if bdev can be claimed
+ * false - if bdev can't be claimed
+ */
+static bool
+raid_bdev_can_claim_bdev(const char *bdev_name, struct raid_bdev_config **_raid_cfg,
+			 uint32_t *base_bdev_slot)
+{
+	struct raid_bdev_config *raid_cfg;
+	uint32_t i;
+
+	TAILQ_FOREACH(raid_cfg, &g_spdk_raid_config.raid_bdev_config_head, link) {
+		for (i = 0; i < raid_cfg->num_base_bdevs; i++) {
+			/*
+			 * Check if the base bdev name is part of raid bdev configuration.
+			 * If match is found then return true and the slot information where
+			 * this base bdev should be inserted in raid bdev
+			 */
+			if (!strcmp(bdev_name, raid_cfg->base_bdev[i].name)) {
+				*_raid_cfg = raid_cfg;
+				*base_bdev_slot = i;
+				return true;
+			}
+		}
+	}
+
+	return false;
+}
+
+
+static struct spdk_bdev_module g_raid_if = {
+	.name = "raid",
+	.module_init = raid_bdev_init,
+	.fini_start = raid_bdev_fini_start,
+	.module_fini = raid_bdev_exit,
+	.get_ctx_size = raid_bdev_get_ctx_size,
+	.examine_config = raid_bdev_examine,
+	.config_text = raid_bdev_get_running_config,
+	.async_init = false,
+	.async_fini = false,
+};
+SPDK_BDEV_MODULE_REGISTER(&g_raid_if)
+
+/*
+ * brief:
+ * raid_bdev_init is the initialization function for raid bdev module
+ * params:
+ * none
+ * returns:
+ * 0 - success
+ * non zero - failure
+ */
+static int
+raid_bdev_init(void)
+{
+	int ret;
+
+	TAILQ_INIT(&g_spdk_raid_bdev_configured_list);
+	TAILQ_INIT(&g_spdk_raid_bdev_configuring_list);
+	TAILQ_INIT(&g_spdk_raid_bdev_list);
+	TAILQ_INIT(&g_spdk_raid_bdev_offline_list);
+
+	/* Parse config file for raids */
+	ret = raid_bdev_parse_config();
+	if (ret < 0) {
+		SPDK_ERRLOG("raid bdev init failed parsing\n");
+		raid_bdev_free();
+		return ret;
+	}
+
+	SPDK_DEBUGLOG(SPDK_LOG_BDEV_RAID, "raid_bdev_init completed successfully\n");
+
+	return 0;
+}
+
+/*
+ * brief:
+ * raid_bdev_create allocates raid bdev based on passed configuration
+ * params:
+ * raid_cfg - configuration of raid bdev
+ * returns:
+ * 0 - success
+ * non zero - failure
+ */
+int
+raid_bdev_create(struct raid_bdev_config *raid_cfg)
+{
+	struct raid_bdev *raid_bdev;
+	struct spdk_bdev *raid_bdev_gen;
+
+	raid_bdev = calloc(1, sizeof(*raid_bdev));
+	if (!raid_bdev) {
+		SPDK_ERRLOG("Unable to allocate memory for raid bdev\n");
+		return -ENOMEM;
+	}
+
+	assert(raid_cfg->num_base_bdevs != 0);
+	raid_bdev->num_base_bdevs = raid_cfg->num_base_bdevs;
+	raid_bdev->base_bdev_info = calloc(raid_bdev->num_base_bdevs,
+					   sizeof(struct raid_base_bdev_info));
+	if (!raid_bdev->base_bdev_info) {
+		SPDK_ERRLOG("Unable able to allocate base bdev info\n");
+		free(raid_bdev);
+		return -ENOMEM;
+	}
+
+	raid_bdev->strip_size = raid_cfg->strip_size;
+	raid_bdev->state = RAID_BDEV_STATE_CONFIGURING;
+	raid_bdev->config = raid_cfg;
+
+	raid_bdev_gen = &raid_bdev->bdev;
+
+	raid_bdev_gen->name = strdup(raid_cfg->name);
+	if (!raid_bdev_gen->name) {
+		SPDK_ERRLOG("Unable to allocate name for raid\n");
+		free(raid_bdev->base_bdev_info);
+		free(raid_bdev);
+		return -ENOMEM;
+	}
+
+	raid_bdev_gen->product_name = "Pooled Device";
+	raid_bdev_gen->ctxt = raid_bdev;
+	raid_bdev_gen->fn_table = &g_raid_bdev_fn_table;
+	raid_bdev_gen->module = &g_raid_if;
+
+	TAILQ_INSERT_TAIL(&g_spdk_raid_bdev_configuring_list, raid_bdev, state_link);
+	TAILQ_INSERT_TAIL(&g_spdk_raid_bdev_list, raid_bdev, global_link);
+
+	raid_cfg->raid_bdev = raid_bdev;
+
+	return 0;
+}
+
+/*
+ * brief
+ * raid_bdev_alloc_base_bdev_resource allocates resource of base bdev.
+ * params:
+ * raid_bdev - pointer to raid bdev
+ * bdev - pointer to base bdev
+ * base_bdev_slot - position to add base bdev
+ * returns:
+ * 0 - success
+ * non zero - failure
+ */
+static int
+raid_bdev_alloc_base_bdev_resource(struct raid_bdev *raid_bdev, struct spdk_bdev *bdev,
+				   uint32_t base_bdev_slot)
+{
+	struct spdk_bdev_desc *desc;
+	int rc;
+
+	rc = spdk_bdev_open(bdev, true, raid_bdev_remove_base_bdev, bdev, &desc);
+	if (rc != 0) {
+		SPDK_ERRLOG("Unable to create desc on bdev '%s'\n", bdev->name);
+		return rc;
+	}
+
+	rc = spdk_bdev_module_claim_bdev(bdev, NULL, &g_raid_if);
+	if (rc != 0) {
+		SPDK_ERRLOG("Unable to claim this bdev as it is already claimed\n");
+		spdk_bdev_close(desc);
+		return rc;
+	}
+
+	SPDK_DEBUGLOG(SPDK_LOG_BDEV_RAID, "bdev %s is claimed\n", bdev->name);
+
+	assert(raid_bdev->state != RAID_BDEV_STATE_ONLINE);
+	assert(base_bdev_slot < raid_bdev->num_base_bdevs);
+
+	raid_bdev->base_bdev_info[base_bdev_slot].bdev = bdev;
+	raid_bdev->base_bdev_info[base_bdev_slot].desc = desc;
+	raid_bdev->num_base_bdevs_discovered++;
+	assert(raid_bdev->num_base_bdevs_discovered <= raid_bdev->num_base_bdevs);
+
+	return 0;
+}
+
+/*
+ * brief:
+ * If raid bdev config is complete, then only register the raid bdev to
+ * bdev layer and remove this raid bdev from configuring list and
+ * insert the raid bdev to configured list
+ * params:
+ * raid_bdev - pointer to raid bdev
+ * returns:
+ * 0 - success
+ * non zero - failure
+ */
+static int
+raid_bdev_configure(struct raid_bdev *raid_bdev)
+{
+	uint32_t		blocklen;
+	uint64_t		min_blockcnt;
+	struct spdk_bdev	*raid_bdev_gen;
+	int rc = 0;
+
+	blocklen = raid_bdev->base_bdev_info[0].bdev->blocklen;
+	min_blockcnt = raid_bdev->base_bdev_info[0].bdev->blockcnt;
+	for (uint32_t i = 1; i < raid_bdev->num_base_bdevs; i++) {
+		/* Calculate minimum block count from all base bdevs */
+		if (raid_bdev->base_bdev_info[i].bdev->blockcnt < min_blockcnt) {
+			min_blockcnt = raid_bdev->base_bdev_info[i].bdev->blockcnt;
+		}
+
+		/* Check blocklen for all base bdevs that it should be same */
+		if (blocklen != raid_bdev->base_bdev_info[i].bdev->blocklen) {
+			/*
+			 * Assumption is that all the base bdevs for any raid bdev should
+			 * have same blocklen
+			 */
+			SPDK_ERRLOG("Blocklen of various bdevs not matching\n");
+			return -EINVAL;
+		}
+	}
+
+	raid_bdev_gen = &raid_bdev->bdev;
+	raid_bdev_gen->write_cache = 0;
+	raid_bdev_gen->blocklen = blocklen;
+	raid_bdev_gen->ctxt = raid_bdev;
+	raid_bdev_gen->fn_table = &g_raid_bdev_fn_table;
+	raid_bdev_gen->module = &g_raid_if;
+	raid_bdev->strip_size = (raid_bdev->strip_size * 1024) / blocklen;
+	raid_bdev->strip_size_shift = spdk_u32log2(raid_bdev->strip_size);
+	raid_bdev->blocklen_shift = spdk_u32log2(blocklen);
+	if (raid_bdev->num_base_bdevs > 1) {
+		raid_bdev_gen->optimal_io_boundary = raid_bdev->strip_size;
+		raid_bdev_gen->split_on_optimal_io_boundary = true;
+	} else {
+		/* Do not need to split reads/writes on single bdev RAID modules. */
+		raid_bdev_gen->optimal_io_boundary = 0;
+		raid_bdev_gen->split_on_optimal_io_boundary = false;
+	}
+
+	/*
+	 * RAID bdev logic is for striping so take the minimum block count based
+	 * approach where total block count of raid bdev is the number of base
+	 * bdev times the minimum block count of any base bdev
+	 */
+	SPDK_DEBUGLOG(SPDK_LOG_BDEV_RAID, "min blockcount %lu,  numbasedev %u, strip size shift %u\n",
+		      min_blockcnt,
+		      raid_bdev->num_base_bdevs, raid_bdev->strip_size_shift);
+	raid_bdev_gen->blockcnt = ((min_blockcnt >> raid_bdev->strip_size_shift) <<
+				   raid_bdev->strip_size_shift)  * raid_bdev->num_base_bdevs;
+	SPDK_DEBUGLOG(SPDK_LOG_BDEV_RAID, "io device register %p\n", raid_bdev);
+	SPDK_DEBUGLOG(SPDK_LOG_BDEV_RAID, "blockcnt %lu, blocklen %u\n", raid_bdev_gen->blockcnt,
+		      raid_bdev_gen->blocklen);
+	if (raid_bdev->state == RAID_BDEV_STATE_CONFIGURING) {
+		raid_bdev->state = RAID_BDEV_STATE_ONLINE;
+		spdk_io_device_register(raid_bdev, raid_bdev_create_cb, raid_bdev_destroy_cb,
+					sizeof(struct raid_bdev_io_channel),
+					raid_bdev->bdev.name);
+		rc = spdk_bdev_register(raid_bdev_gen);
+		if (rc != 0) {
+			SPDK_ERRLOG("Unable to register pooled bdev and stay at configuring state\n");
+			spdk_io_device_unregister(raid_bdev, NULL);
+			raid_bdev->state = RAID_BDEV_STATE_CONFIGURING;
+			return rc;
+		}
+		SPDK_DEBUGLOG(SPDK_LOG_BDEV_RAID, "raid bdev generic %p\n", raid_bdev_gen);
+		TAILQ_REMOVE(&g_spdk_raid_bdev_configuring_list, raid_bdev, state_link);
+		TAILQ_INSERT_TAIL(&g_spdk_raid_bdev_configured_list, raid_bdev, state_link);
+		SPDK_DEBUGLOG(SPDK_LOG_BDEV_RAID, "raid bdev is created with name %s, raid_bdev %p\n",
+			      raid_bdev_gen->name, raid_bdev);
+	}
+
+	return 0;
+}
+
+/*
+ * brief:
+ * If raid bdev is online and registered, change the bdev state to
+ * configuring and unregister this raid device. Queue this raid device
+ * in configuring list
+ * params:
+ * raid_bdev - pointer to raid bdev
+ * returns:
+ * none
+ */
+static void
+raid_bdev_deconfigure(struct raid_bdev *raid_bdev)
+{
+	if (raid_bdev->state != RAID_BDEV_STATE_ONLINE) {
+		return;
+	}
+
+	assert(raid_bdev->num_base_bdevs == raid_bdev->num_base_bdevs_discovered);
+	TAILQ_REMOVE(&g_spdk_raid_bdev_configured_list, raid_bdev, state_link);
+	raid_bdev->state = RAID_BDEV_STATE_OFFLINE;
+	assert(raid_bdev->num_base_bdevs_discovered);
+	TAILQ_INSERT_TAIL(&g_spdk_raid_bdev_offline_list, raid_bdev, state_link);
+	SPDK_DEBUGLOG(SPDK_LOG_BDEV_RAID, "raid bdev state chaning from online to offline\n");
+
+	spdk_io_device_unregister(raid_bdev, NULL);
+	spdk_bdev_unregister(&raid_bdev->bdev, NULL, NULL);
+}
+
+/*
+ * brief:
+ * raid_bdev_remove_base_bdev function is called by below layers when base_bdev
+ * is removed. This function checks if this base bdev is part of any raid bdev
+ * or not. If yes, it takes necessary action on that particular raid bdev.
+ * params:
+ * ctx - pointer to base bdev pointer which got removed
+ * returns:
+ * none
+ */
+void
+raid_bdev_remove_base_bdev(void *ctx)
+{
+	struct    spdk_bdev       *base_bdev = ctx;
+	struct    raid_bdev       *raid_bdev;
+	uint16_t                  i;
+	bool                      found = false;
+
+	SPDK_DEBUGLOG(SPDK_LOG_BDEV_RAID, "raid_bdev_remove_base_bdev\n");
+
+	/* Find the raid_bdev which has claimed this base_bdev */
+	TAILQ_FOREACH(raid_bdev, &g_spdk_raid_bdev_list, global_link) {
+		for (i = 0; i < raid_bdev->num_base_bdevs; i++) {
+			if (raid_bdev->base_bdev_info[i].bdev == base_bdev) {
+				found = true;
+				break;
+			}
+		}
+		if (found == true) {
+			break;
+		}
+	}
+
+	if (found == false) {
+		SPDK_ERRLOG("bdev to remove '%s' not found\n", base_bdev->name);
+		return;
+	}
+
+	assert(raid_bdev != NULL);
+	assert(raid_bdev->base_bdev_info[i].bdev);
+	assert(raid_bdev->base_bdev_info[i].desc);
+	raid_bdev->base_bdev_info[i].remove_scheduled = true;
+
+	if ((raid_bdev->destruct_called == true ||
+	     raid_bdev->state == RAID_BDEV_STATE_CONFIGURING) &&
+	    raid_bdev->base_bdev_info[i].bdev != NULL) {
+		/*
+		 * As raid bdev is not registered yet or already unregistered, so cleanup
+		 * should be done here itself
+		 */
+		raid_bdev_free_base_bdev_resource(raid_bdev, i);
+		if (raid_bdev->num_base_bdevs_discovered == 0) {
+			/* Since there is no base bdev for this raid, so free the raid device */
+			raid_bdev_cleanup(raid_bdev);
+			return;
+		}
+	}
+
+	raid_bdev_deconfigure(raid_bdev);
+}
+
+/*
+ * brief:
+ * raid_bdev_add_base_device function is the actual function which either adds
+ * the nvme base device to existing raid bdev or create a new raid bdev. It also claims
+ * the base device and keep the open descriptor.
+ * params:
+ * raid_cfg - pointer to raid bdev config
+ * bdev - pointer to base bdev
+ * base_bdev_slot - position to add base bdev
+ * returns:
+ * 0 - success
+ * non zero - failure
+ */
+static int
+raid_bdev_add_base_device(struct raid_bdev_config *raid_cfg, struct spdk_bdev *bdev,
+			  uint32_t base_bdev_slot)
+{
+	struct raid_bdev	*raid_bdev;
+	int			rc;
+
+	raid_bdev = raid_cfg->raid_bdev;
+	if (!raid_bdev) {
+		SPDK_ERRLOG("Raid bdev is not created yet '%s'\n", bdev->name);
+		return -ENODEV;
+	}
+
+	rc = raid_bdev_alloc_base_bdev_resource(raid_bdev, bdev, base_bdev_slot);
+	if (rc != 0) {
+		SPDK_ERRLOG("Failed to allocate resource for bdev '%s'\n", bdev->name);
+		return rc;
+	}
+
+	assert(raid_bdev->num_base_bdevs_discovered <= raid_bdev->num_base_bdevs);
+
+	if (raid_bdev->num_base_bdevs_discovered == raid_bdev->num_base_bdevs) {
+		rc = raid_bdev_configure(raid_bdev);
+		if (rc != 0) {
+			SPDK_ERRLOG("Failed to configure raid bdev\n");
+			return rc;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * brief:
+ * Add base bdevs to the raid bdev one by one.  Skip any base bdev which doesn't
+ *  exist or fails to add. If all base bdevs are successfully added, the raid bdev
+ *  moves to the configured state and becomes available. Otherwise, the raid bdev
+ *  stays at the configuring state with added base bdevs.
+ * params:
+ * raid_cfg - pointer to raid bdev config
+ * returns:
+ * 0 - The raid bdev moves to the configured state or stays at the configuring
+ *     state with added base bdevs due to any nonexistent base bdev.
+ * non zero - Failed to add any base bdev and stays at the configuring state with
+ *            added base bdevs.
+ */
+int
+raid_bdev_add_base_devices(struct raid_bdev_config *raid_cfg)
+{
+	struct spdk_bdev	*base_bdev;
+	uint8_t			i;
+	int			rc = 0, _rc;
+
+	for (i = 0; i < raid_cfg->num_base_bdevs; i++) {
+		base_bdev = spdk_bdev_get_by_name(raid_cfg->base_bdev[i].name);
+		if (base_bdev == NULL) {
+			SPDK_DEBUGLOG(SPDK_LOG_BDEV_RAID, "base bdev %s doesn't exist now\n",
+				      raid_cfg->base_bdev[i].name);
+			continue;
+		}
+
+		_rc = raid_bdev_add_base_device(raid_cfg, base_bdev, i);
+		if (_rc != 0) {
+			SPDK_ERRLOG("Failed to add base bdev %s to RAID bdev %s: %s\n",
+				    raid_cfg->base_bdev[i].name, raid_cfg->name,
+				    spdk_strerror(-_rc));
+			if (rc == 0) {
+				rc = _rc;
+			}
+		}
+	}
+
+	return rc;
+}
+
+/*
+ * brief:
+ * raid_bdev_examine function is the examine function call by the below layers
+ * like bdev_nvme layer. This function will check if this base bdev can be
+ * claimed by this raid bdev or not.
+ * params:
+ * bdev - pointer to base bdev
+ * returns:
+ * none
+ */
+static void
+raid_bdev_examine(struct spdk_bdev *bdev)
+{
+	struct raid_bdev_config	*raid_cfg;
+	uint32_t		base_bdev_slot;
+
+	if (raid_bdev_can_claim_bdev(bdev->name, &raid_cfg, &base_bdev_slot)) {
+		raid_bdev_add_base_device(raid_cfg, bdev, base_bdev_slot);
+	} else {
+		SPDK_DEBUGLOG(SPDK_LOG_BDEV_RAID, "bdev %s can't be claimed\n",
+			      bdev->name);
+	}
+
+	spdk_bdev_module_examine_done(&g_raid_if);
+}
+
+/* Log component for bdev raid bdev module */
+SPDK_LOG_REGISTER_COMPONENT("bdev_raid", SPDK_LOG_BDEV_RAID)