nvmet: Convert to bdev_open_by_path()

Convert nvmet to use bdev_open_by_path() and pass the handle around.

CC: linux-nvme@lists.infradead.org
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230927093442.25915-13-jack@suse.cz
Signed-off-by: Christian Brauner <brauner@kernel.org>

drivers/nvme/target/io-cmd-bdev.c

@@ -50,9 +50,10 @@ void nvmet_bdev_set_limits(struct block_device *bdev, struct nvme_id_ns *id)
 
 void nvmet_bdev_ns_disable(struct nvmet_ns *ns)
 {
-	if (ns->bdev) {
-		blkdev_put(ns->bdev, NULL);
+	if (ns->bdev_handle) {
+		bdev_release(ns->bdev_handle);
 		ns->bdev = NULL;
+		ns->bdev_handle = NULL;
 	}
 }
 
@@ -84,17 +85,18 @@ int nvmet_bdev_ns_enable(struct nvmet_ns *ns)
 	if (ns->buffered_io)
 		return -ENOTBLK;
 
-	ns->bdev = blkdev_get_by_path(ns->device_path,
-			BLK_OPEN_READ | BLK_OPEN_WRITE, NULL, NULL);
-	if (IS_ERR(ns->bdev)) {
-		ret = PTR_ERR(ns->bdev);
+	ns->bdev_handle = bdev_open_by_path(ns->device_path,
+				BLK_OPEN_READ | BLK_OPEN_WRITE, NULL, NULL);
+	if (IS_ERR(ns->bdev_handle)) {
+		ret = PTR_ERR(ns->bdev_handle);
 		if (ret != -ENOTBLK) {
-			pr_err("failed to open block device %s: (%ld)\n",
-					ns->device_path, PTR_ERR(ns->bdev));
+			pr_err("failed to open block device %s: (%d)\n",
+					ns->device_path, ret);
 		}
-		ns->bdev = NULL;
+		ns->bdev_handle = NULL;
 		return ret;
 	}
+	ns->bdev = ns->bdev_handle->bdev;
 	ns->size = bdev_nr_bytes(ns->bdev);
 	ns->blksize_shift = blksize_bits(bdev_logical_block_size(ns->bdev));
 

drivers/nvme/target/nvmet.h

@@ -58,6 +58,7 @@
 
 struct nvmet_ns {
 	struct percpu_ref	ref;
+	struct bdev_handle	*bdev_handle;
 	struct block_device	*bdev;
 	struct file		*file;
 	bool			readonly;