Bdev ext api

CHANGELOG.md

@@ -10,6 +10,9 @@ parameter in spdk_bdev_get_opts function. Two fields `small_buf_pool_size` and
 `large_buf_pool_size` were added into spdk_bdev_opts, which were used to determine
 the small and large buffer pool size of the whole bdev module.
 
+New API `spdk_bdev_get_caps` has been added, it allows to get extended bdev module
+capabilities.
+
 ### blob
 
 An `opts_size` element was added in the `spdk_bs_opts` structure to solve the

include/spdk/bdev.h

@@ -1733,6 +1733,30 @@ void spdk_bdev_histogram_get(struct spdk_bdev *bdev, struct spdk_histogram_data
 size_t spdk_bdev_get_media_events(struct spdk_bdev_desc *bdev_desc,
 				  struct spdk_bdev_media_event *events, size_t max_events);
 
+enum spdk_bdev_capability_type {
+	/** Bdev supports indirect memory access using Memory Key.
+	 * That means that the user of ext bdev API can fill spdk_bdev_ext_io_opts_mem_type
+	 * structure and set SPDK_BDEV_EXT_IO_OPTS_MEM_TYPE flag in spdk_bdev_ext_io_opts structure */
+	SPDK_BDEV_CAP_EXT_MEMORY_TYPE_MKEY = 1u << 0u,
+};
+
+/** Describes capabilities of Block device */
+struct spdk_bdev_capability {
+	/** Size of this structure in bytes, should be set by the user */
+	size_t size;
+	/** bitwise combination of \ref spdk_bdev_capability_type */
+	uint64_t flags;
+};
+
+/**
+ * Get bdev capabilities
+ *
+ * \param bdev Block device
+ * \param caps Capabilities of Block device to be filled by this function
+ * \return 0 on success, negated errno on failure.
+ */
+int spdk_bdev_get_caps(struct spdk_bdev *bdev, struct spdk_bdev_capability *caps);
+
 #ifdef __cplusplus
 }
 #endif

include/spdk/bdev_module.h

@@ -222,6 +222,9 @@ struct spdk_bdev_fn_table {
 
 	/** Get bdev module context. */
 	void *(*get_module_ctx)(void *ctx);
+
+	/** Get block device capabilities */
+	void (*get_caps)(void *ctx, struct spdk_bdev_capability *caps);
 };
 
 /** bdev I/O completion status */

lib/bdev/bdev.c

@@ -6813,6 +6813,29 @@ bdev_unlock_lba_range(struct spdk_bdev_desc *desc, struct spdk_io_channel *_ch,
 	return 0;
 }
 
+int
+spdk_bdev_get_caps(struct spdk_bdev *bdev, struct spdk_bdev_capability *caps)
+{
+	struct spdk_bdev_capability caps_local;
+
+	if (!caps || !caps->size) {
+		return -EINVAL;
+	}
+
+	memset(&caps_local, 0, sizeof(caps_local));
+	caps_local.size = spdk_min(sizeof(caps_local), caps->size);
+
+	if (bdev->fn_table->get_caps) {
+		bdev->fn_table->get_caps(bdev->ctxt, &caps_local);
+	}
+
+	/* The user may use older or newer SPDK version where size of this structure can be different.
+	 * Here we copy only the number of bytes requested by the user and supported by SPDK */
+	memcpy(caps, &caps_local, caps_local.size);
+
+	return 0;
+}
+
 SPDK_LOG_REGISTER_COMPONENT(bdev)
 
 SPDK_TRACE_REGISTER_FN(bdev_trace, "bdev", TRACE_GROUP_BDEV)

module/bdev/delay/vbdev_delay.c

@@ -671,6 +671,16 @@ vbdev_delay_write_config_json(struct spdk_bdev *bdev, struct spdk_json_write_ctx
 	/* No config per bdev needed */
 }
 
+static void
+vbdev_delay_get_caps(void *ctx, struct spdk_bdev_capability *caps)
+{
+	struct vbdev_delay *delay_node = (struct vbdev_delay *)ctx;
+
+	if (delay_node->base_bdev->fn_table->get_caps) {
+		delay_node->base_bdev->fn_table->get_caps(delay_node->base_bdev, caps);
+	}
+}
+
 /* When we register our bdev this is how we specify our entry points. */
 static const struct spdk_bdev_fn_table vbdev_delay_fn_table = {
 	.destruct		= vbdev_delay_destruct,
@@ -679,6 +689,7 @@ static const struct spdk_bdev_fn_table vbdev_delay_fn_table = {
 	.get_io_channel		= vbdev_delay_get_io_channel,
 	.dump_info_json		= vbdev_delay_dump_info_json,
 	.write_config_json	= vbdev_delay_write_config_json,
+	.get_caps		= vbdev_delay_get_caps,
 };
 
 static void

module/bdev/nvme/bdev_nvme.c

@@ -980,6 +980,16 @@ bdev_nvme_get_module_ctx(void *ctx)
 	return bdev_nvme_get_ctrlr(&nvme_bdev->disk);
 }
 
+static void
+bdev_nvme_get_caps(void *ctx, struct spdk_bdev_capability *caps)
+{
+	struct nvme_bdev *nbdev = ctx;
+
+	if (nbdev->nvme_ns->ctrlr->connected_trid->trtype == SPDK_NVME_TRANSPORT_RDMA) {
+		caps->flags |= SPDK_BDEV_CAP_EXT_MEMORY_TYPE_MKEY;
+	}
+}
+
 static int
 bdev_nvme_dump_info_json(void *ctx, struct spdk_json_write_ctx *w)
 {
@@ -1132,6 +1142,7 @@ static const struct spdk_bdev_fn_table nvmelib_fn_table = {
 	.write_config_json	= bdev_nvme_write_config_json,
 	.get_spin_time		= bdev_nvme_get_spin_time,
 	.get_module_ctx		= bdev_nvme_get_module_ctx,
+	.get_caps			= bdev_nvme_get_caps,
 };
 
 static int

module/bdev/passthru/vbdev_passthru.c

@@ -550,6 +550,16 @@ vbdev_passthru_write_config_json(struct spdk_bdev *bdev, struct spdk_json_write_
 	/* No config per bdev needed */
 }
 
+static void
+vbdev_passthru_get_caps(void *ctx, struct spdk_bdev_capability *caps)
+{
+	struct vbdev_passthru *pt_node = (struct vbdev_passthru *)ctx;
+
+	if (pt_node->base_bdev->fn_table->get_caps) {
+		pt_node->base_bdev->fn_table->get_caps(pt_node->base_bdev, caps);
+	}
+}
+
 /* When we register our bdev this is how we specify our entry points. */
 static const struct spdk_bdev_fn_table vbdev_passthru_fn_table = {
 	.destruct		= vbdev_passthru_destruct,
@@ -558,6 +568,7 @@ static const struct spdk_bdev_fn_table vbdev_passthru_fn_table = {
 	.get_io_channel		= vbdev_passthru_get_io_channel,
 	.dump_info_json		= vbdev_passthru_dump_info_json,
 	.write_config_json	= vbdev_passthru_write_config_json,
+	.get_caps		= vbdev_passthru_get_caps,
 };
 
 static void