Merge series 'Open block devices as files' of https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-0-adbd023e19cc@kernel.org

Pull block devices as files from Christian Brauner:

This opens block devices as files. Instead of introducing a separate
indirection into bdev_open_by_*() vis struct bdev_handle we can just
make bdev_file_open_by_*() return a struct file. Opening and closing a
block device from setup_bdev_super() and in all other places just
becomes equivalent to opening and closing a file.

This has held up in xfstests and in blktests so far and it seems stable
and clean. The equivalence of opening and closing block devices to
regular files is a win in and of itself imho. Added to that is the
ability to do away with struct bdev_handle completely and make various
low-level helpers private to the block layer.

All places were we currently stash a struct bdev_handle we just stash a
file and use an accessor such as file_bdev() akin to I_BDEV() to get to
the block device.

It's now also possible to use file->f_mapping as a replacement for
bdev->bd_inode->i_mapping and file->f_inode or file->f_mapping->host as
an alternative to bdev->bd_inode allowing us to significantly reduce or
even fully remove bdev->bd_inode in follow-up patches.

In addition, we could get rid of sb->s_bdev and various other places
that stash the block device directly and instead stash the block device
file. Again, this is follow-up work if we want this.

* series 'Open block devices as files' of https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-0-adbd023e19cc@kernel.org: (35 commits)
  file: add alloc_file_pseudo_noaccount()
  file: prepare for new helper
  init: flush async file closing
  block: remove bdev_handle completely
  block: don't rely on BLK_OPEN_RESTRICT_WRITES when yielding write access
  bdev: remove bdev pointer from struct bdev_handle
  bdev: make struct bdev_handle private to the block layer
  bdev: make bdev_{release, open_by_dev}() private to block layer
  bdev: remove bdev_open_by_path()
  reiserfs: port block device access to file
  ocfs2: port block device access to file
  nfs: port block device access to files
  jfs: port block device access to file
  f2fs: port block device access to files
  ext4: port block device access to file
  erofs: port device access to file
  btrfs: port device access to file
  bcachefs: port block device access to file
  target: port block device access to file
  s390: port block device access to file
  nvme: port block device access to file
  block2mtd: port device access to files
  bcache: port block device access to files
  ...

Signed-off-by: Christian Brauner <brauner@kernel.org>

4 files changed, 22 insertions, 22 deletions

diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index 8eb9eb7ce5df..7f6ca8177845 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -91,7 +91,7 @@ static int iblock_configure_device(struct se_device *dev)
 {
 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 	struct request_queue *q;
-	struct bdev_handle *bdev_handle;
+	struct file *bdev_file;
 	struct block_device *bd;
 	struct blk_integrity *bi;
 	blk_mode_t mode = BLK_OPEN_READ;
@@ -117,14 +117,14 @@ static int iblock_configure_device(struct se_device *dev)
 	else
 		dev->dev_flags |= DF_READ_ONLY;
 
-	bdev_handle = bdev_open_by_path(ib_dev->ibd_udev_path, mode, ib_dev,
+	bdev_file = bdev_file_open_by_path(ib_dev->ibd_udev_path, mode, ib_dev,
 					NULL);
-	if (IS_ERR(bdev_handle)) {
-		ret = PTR_ERR(bdev_handle);
+	if (IS_ERR(bdev_file)) {
+		ret = PTR_ERR(bdev_file);
 		goto out_free_bioset;
 	}
-	ib_dev->ibd_bdev_handle = bdev_handle;
-	ib_dev->ibd_bd = bd = bdev_handle->bdev;
+	ib_dev->ibd_bdev_file = bdev_file;
+	ib_dev->ibd_bd = bd = file_bdev(bdev_file);
 
 	q = bdev_get_queue(bd);
 
@@ -180,7 +180,7 @@ static int iblock_configure_device(struct se_device *dev)
 	return 0;
 
 out_blkdev_put:
-	bdev_release(ib_dev->ibd_bdev_handle);
+	fput(ib_dev->ibd_bdev_file);
 out_free_bioset:
 	bioset_exit(&ib_dev->ibd_bio_set);
 out:
@@ -205,8 +205,8 @@ static void iblock_destroy_device(struct se_device *dev)
 {
 	struct iblock_dev *ib_dev = IBLOCK_DEV(dev);
 
-	if (ib_dev->ibd_bdev_handle)
-		bdev_release(ib_dev->ibd_bdev_handle);
+	if (ib_dev->ibd_bdev_file)
+		fput(ib_dev->ibd_bdev_file);
 	bioset_exit(&ib_dev->ibd_bio_set);
 }
 
diff --git a/drivers/target/target_core_iblock.h b/drivers/target/target_core_iblock.h
index 683f9a55945b..91f6f4280666 100644
--- a/drivers/target/target_core_iblock.h
+++ b/drivers/target/target_core_iblock.h
@@ -32,7 +32,7 @@ struct iblock_dev {
 	u32	ibd_flags;
 	struct bio_set	ibd_bio_set;
 	struct block_device *ibd_bd;
-	struct bdev_handle *ibd_bdev_handle;
+	struct file *ibd_bdev_file;
 	bool ibd_readonly;
 	struct iblock_dev_plug *ibd_plug;
 } ____cacheline_aligned;
diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c
index 41b7489d37ce..9aedd682d10c 100644
--- a/drivers/target/target_core_pscsi.c
+++ b/drivers/target/target_core_pscsi.c
@@ -352,7 +352,7 @@ static int pscsi_create_type_disk(struct se_device *dev, struct scsi_device *sd)
 	struct pscsi_hba_virt *phv = dev->se_hba->hba_ptr;
 	struct pscsi_dev_virt *pdv = PSCSI_DEV(dev);
 	struct Scsi_Host *sh = sd->host;
-	struct bdev_handle *bdev_handle;
+	struct file *bdev_file;
 	int ret;
 
 	if (scsi_device_get(sd)) {
@@ -366,18 +366,18 @@ static int pscsi_create_type_disk(struct se_device *dev, struct scsi_device *sd)
 	 * Claim exclusive struct block_device access to struct scsi_device
 	 * for TYPE_DISK and TYPE_ZBC using supplied udev_path
 	 */
-	bdev_handle = bdev_open_by_path(dev->udev_path,
+	bdev_file = bdev_file_open_by_path(dev->udev_path,
 				BLK_OPEN_WRITE | BLK_OPEN_READ, pdv, NULL);
-	if (IS_ERR(bdev_handle)) {
+	if (IS_ERR(bdev_file)) {
 		pr_err("pSCSI: bdev_open_by_path() failed\n");
 		scsi_device_put(sd);
-		return PTR_ERR(bdev_handle);
+		return PTR_ERR(bdev_file);
 	}
-	pdv->pdv_bdev_handle = bdev_handle;
+	pdv->pdv_bdev_file = bdev_file;
 
 	ret = pscsi_add_device_to_list(dev, sd);
 	if (ret) {
-		bdev_release(bdev_handle);
+		fput(bdev_file);
 		scsi_device_put(sd);
 		return ret;
 	}
@@ -564,9 +564,9 @@ static void pscsi_destroy_device(struct se_device *dev)
 		 * from pscsi_create_type_disk()
 		 */
 		if ((sd->type == TYPE_DISK || sd->type == TYPE_ZBC) &&
-		    pdv->pdv_bdev_handle) {
-			bdev_release(pdv->pdv_bdev_handle);
-			pdv->pdv_bdev_handle = NULL;
+		    pdv->pdv_bdev_file) {
+			fput(pdv->pdv_bdev_file);
+			pdv->pdv_bdev_file = NULL;
 		}
 		/*
 		 * For HBA mode PHV_LLD_SCSI_HOST_NO, release the reference
@@ -994,8 +994,8 @@ static sector_t pscsi_get_blocks(struct se_device *dev)
 {
 	struct pscsi_dev_virt *pdv = PSCSI_DEV(dev);
 
-	if (pdv->pdv_bdev_handle)
-		return bdev_nr_sectors(pdv->pdv_bdev_handle->bdev);
+	if (pdv->pdv_bdev_file)
+		return bdev_nr_sectors(file_bdev(pdv->pdv_bdev_file));
 	return 0;
 }
 
diff --git a/drivers/target/target_core_pscsi.h b/drivers/target/target_core_pscsi.h
index b0a3ef136592..9acaa21e4c78 100644
--- a/drivers/target/target_core_pscsi.h
+++ b/drivers/target/target_core_pscsi.h
@@ -37,7 +37,7 @@ struct pscsi_dev_virt {
 	int	pdv_channel_id;
 	int	pdv_target_id;
 	int	pdv_lun_id;
-	struct bdev_handle *pdv_bdev_handle;
+	struct file *pdv_bdev_file;
 	struct scsi_device *pdv_sd;
 	struct Scsi_Host *pdv_lld_host;
 } ____cacheline_aligned;