blob/bdev: Add an API spdk_bdev_create_bs_dev_ext()

spdk_bdev_open_ext() requires the caller to use bdev_event_cb_t
and bdev_event_cb_t is more extensible than bdev_remove_cb_t.
Hence use bdev_event_t as an argument.

spdk_bdev_open_ext() calls spdk_bdev_get_by_name() inside and
spdk_bdev_create_bs_dev_ext() calls spdk_bdev_open_ext() inside.
The caller needs to know if the spdk_bdev_get_by_name() succeeded.
Hence spdk_bdev_create_bs_dev_ext() returns return code by return
value and returns the created bs_dev by double pointer.

Signed-off-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Change-Id: I1c225bfb66db036439c69c459f39c86684d8a540
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/4692
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-by: Aleksey Marchuk <alexeymar@mellanox.com>

CHANGELOG.md

@@ -16,6 +16,11 @@ A new `spdk_bdev_part_base_construct_ext` function has been added and the
 of bdev structure to avoid a race condition that can happen when the bdev is being
 removed between a call to get its structure based on a name and actually openning it.
 
+### blobstore
+
+A new `spdk_bdev_create_bs_dev_ext` function has been added and `spdk_bdev_create_bs_dev_from_desc`
+function has been deprecated.
+
 ### dpdk
 
 Updated DPDK submodule to DPDK 20.08.

include/spdk/blob_bdev.h

@@ -50,8 +50,7 @@ struct spdk_bdev;
 struct spdk_bdev_module;
 
 /**
- * Create a blobstore block device from a bdev. (deprecated, please use spdk_bdev_create_bs_dev_from_desc,
- * together with spdk_bdev_open_ext).
+ * Create a blobstore block device from a bdev (deprecated, please use spdk_bdev_create_bs_dev_ext).
  *
  * \param bdev Bdev to use.
  * \param remove_cb Called when the block device is removed.
@@ -63,7 +62,7 @@ struct spdk_bs_dev *spdk_bdev_create_bs_dev(struct spdk_bdev *bdev, spdk_bdev_re
 		void *remove_ctx);
 
 /**
- * Create a blobstore block device from the descriptor of a bdev.
+ * Create a blobstore block device from the descriptor of a bdev (deprecated, please use spdk_bdev_create_bs_dev_ext).
  *
  * \param desc Descriptor of a bdev. spdk_bdev_open_ext() is recommended to get the desc.
  *
@@ -71,6 +70,19 @@ struct spdk_bs_dev *spdk_bdev_create_bs_dev(struct spdk_bdev *bdev, spdk_bdev_re
  */
 struct spdk_bs_dev *spdk_bdev_create_bs_dev_from_desc(struct spdk_bdev_desc *desc);
 
+/**
+ * Create a blobstore block device from a bdev.
+ *
+ * \param bdev_name Name of the bdev to use.
+ * \param event_cb Called when the bdev triggers asynchronous event.
+ * \param event_ctx Argument passed to function event_cb.
+ * \param bs_dev Output parameter for a pointer to the blobstore block device.
+ *
+ * \return 0 if operation is successful, or suitable errno value otherwise.
+ */
+int spdk_bdev_create_bs_dev_ext(const char *bdev_name, spdk_bdev_event_cb_t event_cb,
+				void *event_ctx, struct spdk_bs_dev **bs_dev);
+
 /**
  * Claim the bdev module for the given blobstore.
  *

module/blob/bdev/Makefile

@@ -35,7 +35,7 @@ SPDK_ROOT_DIR := $(abspath $(CURDIR)/../../..)
 include $(SPDK_ROOT_DIR)/mk/spdk.common.mk
 
 SO_VER := 3
-SO_MINOR := 0
+SO_MINOR := 1
 
 C_SRCS = blob_bdev.c
 LIBNAME = blob_bdev

module/blob/bdev/blob_bdev.c

@@ -383,3 +383,32 @@ spdk_bdev_create_bs_dev_from_desc(struct spdk_bdev_desc *desc)
 
 	return &b->bs_dev;
 }
+
+
+int
+spdk_bdev_create_bs_dev_ext(const char *bdev_name, spdk_bdev_event_cb_t event_cb,
+			    void *event_ctx, struct spdk_bs_dev **_bs_dev)
+{
+	struct blob_bdev *b;
+	struct spdk_bdev_desc *desc;
+	int rc;
+
+	b = calloc(1, sizeof(*b));
+
+	if (b == NULL) {
+		SPDK_ERRLOG("could not allocate blob_bdev\n");
+		return -ENOMEM;
+	}
+
+	rc = spdk_bdev_open_ext(bdev_name, true, event_cb, event_ctx, &desc);
+	if (rc != 0) {
+		free(b);
+		return rc;
+	}
+
+	blob_bdev_init(b, desc);
+
+	*_bs_dev = &b->bs_dev;
+
+	return 0;
+}

module/blob/bdev/spdk_blob_bdev.map

@@ -4,6 +4,7 @@
 	# public functions
 	spdk_bdev_create_bs_dev;
 	spdk_bdev_create_bs_dev_from_desc;
+	spdk_bdev_create_bs_dev_ext;
 	spdk_bs_bdev_claim;
 
 	local: *;