nvme: introduce nvme_is_fabrics to check fabrics cmd

This patch introduces a nvme_is_fabrics() inline function to check
whether or not the given command structure is for fabrics.

Signed-off-by: Minwoo Im <minwoo.im.dev@gmail.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index 8028ada..7080923 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -1165,6 +1165,11 @@ struct nvme_command {
 	};
 };
 
+static inline bool nvme_is_fabrics(struct nvme_command *cmd)
+{
+	return cmd->common.opcode == nvme_fabrics_command;
+}
+
 struct nvme_error_slot {
 	__le64		error_count;
 	__le16		sqid;
@@ -1186,7 +1191,7 @@ static inline bool nvme_is_write(struct nvme_command *cmd)
 	 *
 	 * Why can't we simply have a Fabrics In and Fabrics out command?
 	 */
-	if (unlikely(cmd->common.opcode == nvme_fabrics_command))
+	if (unlikely(nvme_is_fabrics(cmd)))
 		return cmd->fabrics.fctype & 1;
 	return cmd->common.opcode & 1;
 }