bdev: extend interface with get module ctx

Currently only nvme bdev module implements this interface. Bdev module
context (in this case spdk_nvme_ctrlr opaque handle) allows for nvme
interface usage for additional management.

Signed-off-by: Jacek Kalwas <jacek.kalwas@intel.com>
Change-Id: I6302c9229d5f7f294a3c1472d9e8dc1519637ffb
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/4924
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Aleksey Marchuk <alexeymar@mellanox.com>

include/spdk/bdev.h

@@ -249,6 +249,14 @@ void spdk_bdev_finish(spdk_bdev_fini_cb cb_fn, void *cb_arg);
  */
 void spdk_bdev_subsystem_config_json(struct spdk_json_write_ctx *w);
 
+/**
+ * Get block device module name.
+ *
+ * \param bdev Block device to query.
+ * \return Name of bdev module as a null-terminated string.
+ */
+const char *spdk_bdev_get_module_name(const struct spdk_bdev *bdev);
+
 /**
  * Get block device by the block device name.
  *
@@ -686,6 +694,16 @@ uint64_t spdk_bdev_get_weighted_io_time(const struct spdk_bdev *bdev);
  */
 struct spdk_io_channel *spdk_bdev_get_io_channel(struct spdk_bdev_desc *desc);
 
+/**
+ * Obtain a bdev module context for the block device opened by the specified
+ * descriptor.
+ *
+ * \param desc Block device descriptor.
+ *
+ * \return A bdev module context or NULL on failure.
+ */
+void *spdk_bdev_get_module_ctx(struct spdk_bdev_desc *desc);
+
 /**
  * \defgroup bdev_io_submit_functions bdev I/O Submit Functions
  *

include/spdk/bdev_module.h

@@ -219,6 +219,9 @@ struct spdk_bdev_fn_table {
 	 *  Optional - may be NULL.
 	 */
 	uint64_t (*get_spin_time)(struct spdk_io_channel *ch);
+
+	/** Get bdev module context. */
+	void *(*get_module_ctx)(void *ctx);
 };
 
 /** bdev I/O completion status */

lib/bdev/bdev.c

@@ -2966,6 +2966,25 @@ spdk_bdev_get_io_channel(struct spdk_bdev_desc *desc)
 	return spdk_get_io_channel(__bdev_to_io_dev(spdk_bdev_desc_get_bdev(desc)));
 }
 
+void *
+spdk_bdev_get_module_ctx(struct spdk_bdev_desc *desc)
+{
+	struct spdk_bdev *bdev = spdk_bdev_desc_get_bdev(desc);
+	void *ctx = NULL;
+
+	if (bdev->fn_table->get_module_ctx) {
+		ctx = bdev->fn_table->get_module_ctx(bdev->ctxt);
+	}
+
+	return ctx;
+}
+
+const char *
+spdk_bdev_get_module_name(const struct spdk_bdev *bdev)
+{
+	return bdev->module->name;
+}
+
 const char *
 spdk_bdev_get_name(const struct spdk_bdev *bdev)
 {

lib/bdev/spdk_bdev.map

@@ -9,6 +9,7 @@
 	spdk_bdev_finish;
 	spdk_bdev_subsystem_config_json;
 	spdk_bdev_get_by_name;
+	spdk_bdev_get_module_name;
 	spdk_bdev_first;
 	spdk_bdev_next;
 	spdk_bdev_first_leaf;
@@ -47,6 +48,7 @@
 	spdk_bdev_get_io_time;
 	spdk_bdev_get_weighted_io_time;
 	spdk_bdev_get_io_channel;
+	spdk_bdev_get_module_ctx;
 	spdk_bdev_read;
 	spdk_bdev_read_blocks;
 	spdk_bdev_read_blocks_with_md;

lib/lvol/Makefile

@@ -34,7 +34,7 @@
 SPDK_ROOT_DIR := $(abspath $(CURDIR)/../..)
 include $(SPDK_ROOT_DIR)/mk/spdk.common.mk
 
-SO_VER := 2
+SO_VER := 3
 SO_MINOR := 0
 
 C_SRCS = lvol.c

module/bdev/nvme/bdev_nvme.c

@@ -920,6 +920,14 @@ bdev_nvme_get_io_channel(void *ctx)
 	return spdk_get_io_channel(nvme_bdev->nvme_ns->ctrlr);
 }
 
+static void *
+bdev_nvme_get_module_ctx(void *ctx)
+{
+	struct nvme_bdev *nvme_bdev = ctx;
+
+	return bdev_nvme_get_ctrlr(&nvme_bdev->disk);
+}
+
 static int
 bdev_nvme_dump_info_json(void *ctx, struct spdk_json_write_ctx *w)
 {
@@ -1066,6 +1074,7 @@ static const struct spdk_bdev_fn_table nvmelib_fn_table = {
 	.dump_info_json		= bdev_nvme_dump_info_json,
 	.write_config_json	= bdev_nvme_write_config_json,
 	.get_spin_time		= bdev_nvme_get_spin_time,
+	.get_module_ctx		= bdev_nvme_get_module_ctx,
 };
 
 static struct nvme_bdev *

module/blob/bdev/Makefile

@@ -34,8 +34,8 @@
 SPDK_ROOT_DIR := $(abspath $(CURDIR)/../../..)
 include $(SPDK_ROOT_DIR)/mk/spdk.common.mk
 
-SO_VER := 3
-SO_MINOR := 1
+SO_VER := 4
+SO_MINOR := 0
 
 C_SRCS = blob_bdev.c
 LIBNAME = blob_bdev