clean up is partition checks

clean up is partition checks

[Christoph Hellwig]

Hi Jens,

this series add a new helepr to check if a struct block_device represents
a parition, and removes most direct access to ->bd_contained from
drivers.

Diffstat:
 Documentation/userspace-api/ioctl/hdio.rst |   24 ++++++++++++------------
 block/blk-lib.c                            |    2 +-
 block/genhd.c                              |    2 +-
 block/ioctl.c                              |    4 ++--
 block/scsi_ioctl.c                         |    2 +-
 drivers/block/drbd/drbd_main.c             |    2 --
 drivers/block/drbd/drbd_receiver.c         |    2 +-
 drivers/block/drbd/drbd_worker.c           |    2 +-
 drivers/ide/ide-ioctls.c                   |    4 ++--
 drivers/md/dm-table.c                      |    2 +-
 drivers/md/md.c                            |    9 ++++-----
 drivers/md/md.h                            |    2 +-
 drivers/mmc/core/block.c                   |    2 +-
 drivers/s390/block/dasd_ioctl.c            |    8 ++++----
 drivers/target/target_core_iblock.c        |    5 ++---
 fs/nfsd/blocklayout.c                      |    4 ++--
 include/linux/blkdev.h                     |    9 +++++++--
 kernel/trace/blktrace.c                    |    2 +-
 lib/vsprintf.c                             |    4 ++--
 19 files changed, 46 insertions(+), 45 deletions(-)

[PATCH 1/9] Documentation/hdio: fix up obscure bd_contains references

[Christoph Hellwig]

bd_contains is an implementation detail and should not be mentioned in
a userspace API documentation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 Documentation/userspace-api/ioctl/hdio.rst | 24 +++++++++++-----------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/Documentation/userspace-api/ioctl/hdio.rst b/Documentation/userspace-api/ioctl/hdio.rst
index e822e3dff1769b..817371bf94e948 100644
--- a/Documentation/userspace-api/ioctl/hdio.rst
+++ b/Documentation/userspace-api/ioctl/hdio.rst
@@ -181,7 +181,7 @@ HDIO_SET_UNMASKINTR
 
 
 	error return:
-	  - EINVAL	(bdev != bdev->bd_contains) (not sure what this means)
+	  - EINVAL	Called on a partition instead of the whole disk device
 	  - EACCES	Access denied:  requires CAP_SYS_ADMIN
 	  - EINVAL	value out of range [0 1]
 	  - EBUSY	Controller busy
@@ -231,7 +231,7 @@ HDIO_SET_MULTCOUNT
 
 
 	error return:
-	  - EINVAL	(bdev != bdev->bd_contains) (not sure what this means)
+	  - EINVAL	Called on a partition instead of the whole disk device
 	  - EACCES	Access denied:  requires CAP_SYS_ADMIN
 	  - EINVAL	value out of range supported by disk.
 	  - EBUSY	Controller busy or blockmode already set.
@@ -295,7 +295,7 @@ HDIO_GET_IDENTITY
 		the ATA specification.
 
 	error returns:
-	  - EINVAL	(bdev != bdev->bd_contains) (not sure what this means)
+	  - EINVAL	Called on a partition instead of the whole disk device
 	  - ENOMSG	IDENTIFY DEVICE information not available
 
 	notes:
@@ -355,7 +355,7 @@ HDIO_SET_KEEPSETTINGS
 
 
 	error return:
-	  - EINVAL	(bdev != bdev->bd_contains) (not sure what this means)
+	  - EINVAL	Called on a partition instead of the whole disk device
 	  - EACCES	Access denied:  requires CAP_SYS_ADMIN
 	  - EINVAL	value out of range [0 1]
 	  - EBUSY		Controller busy
@@ -1055,7 +1055,7 @@ HDIO_SET_32BIT
 
 
 	error return:
-	  - EINVAL	(bdev != bdev->bd_contains) (not sure what this means)
+	  - EINVAL	Called on a partition instead of the whole disk device
 	  - EACCES	Access denied:  requires CAP_SYS_ADMIN
 	  - EINVAL	value out of range [0 3]
 	  - EBUSY	Controller busy
@@ -1085,7 +1085,7 @@ HDIO_SET_NOWERR
 
 
 	error return:
-	  - EINVAL	(bdev != bdev->bd_contains) (not sure what this means)
+	  - EINVAL	Called on a partition instead of the whole disk device
 	  - EACCES	Access denied:  requires CAP_SYS_ADMIN
 	  - EINVAL	value out of range [0 1]
 	  - EBUSY		Controller busy
@@ -1113,7 +1113,7 @@ HDIO_SET_DMA
 
 
 	error return:
-	  - EINVAL	(bdev != bdev->bd_contains) (not sure what this means)
+	  - EINVAL	Called on a partition instead of the whole disk device
 	  - EACCES	Access denied:  requires CAP_SYS_ADMIN
 	  - EINVAL	value out of range [0 1]
 	  - EBUSY	Controller busy
@@ -1141,7 +1141,7 @@ HDIO_SET_PIO_MODE
 
 
 	error return:
-	  - EINVAL	(bdev != bdev->bd_contains) (not sure what this means)
+	  - EINVAL	Called on a partition instead of the whole disk device
 	  - EACCES	Access denied:  requires CAP_SYS_ADMIN
 	  - EINVAL	value out of range [0 255]
 	  - EBUSY	Controller busy
@@ -1237,7 +1237,7 @@ HDIO_SET_WCACHE
 
 
 	error return:
-	  - EINVAL	(bdev != bdev->bd_contains) (not sure what this means)
+	  - EINVAL	Called on a partition instead of the whole disk device
 	  - EACCES	Access denied:  requires CAP_SYS_ADMIN
 	  - EINVAL	value out of range [0 1]
 	  - EBUSY	Controller busy
@@ -1265,7 +1265,7 @@ HDIO_SET_ACOUSTIC
 
 
 	error return:
-	  - EINVAL	(bdev != bdev->bd_contains) (not sure what this means)
+	  - EINVAL	Called on a partition instead of the whole disk device
 	  - EACCES	Access denied:  requires CAP_SYS_ADMIN
 	  - EINVAL	value out of range [0 254]
 	  - EBUSY	Controller busy
@@ -1305,7 +1305,7 @@ HDIO_SET_ADDRESS
 
 
 	error return:
-	  - EINVAL	(bdev != bdev->bd_contains) (not sure what this means)
+	  - EINVAL	Called on a partition instead of the whole disk device
 	  - EACCES	Access denied:  requires CAP_SYS_ADMIN
 	  - EINVAL	value out of range [0 2]
 	  - EBUSY		Controller busy
@@ -1331,7 +1331,7 @@ HDIO_SET_IDE_SCSI
 
 
 	error return:
-	  - EINVAL	(bdev != bdev->bd_contains) (not sure what this means)
+	  - EINVAL	Called on a partition instead of the whole disk device
 	  - EACCES	Access denied:  requires CAP_SYS_ADMIN
 	  - EINVAL	value out of range [0 1]
 	  - EBUSY	Controller busy
-- 
2.28.0

[PATCH 2/9] block: add a bdev_is_partition helper

[Christoph Hellwig]

Add a littler helper to make the somewhat arcane bd_contains checks a
little more obvious.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-lib.c                 | 2 +-
 block/ioctl.c                   | 4 ++--
 block/scsi_ioctl.c              | 2 +-
 drivers/ide/ide-ioctls.c        | 4 ++--
 drivers/md/dm-table.c           | 2 +-
 drivers/mmc/core/block.c        | 2 +-
 drivers/s390/block/dasd_ioctl.c | 8 ++++----
 fs/nfsd/blocklayout.c           | 4 ++--
 include/linux/blkdev.h          | 9 +++++++--
 kernel/trace/blktrace.c         | 2 +-
 10 files changed, 22 insertions(+), 17 deletions(-)

diff --git a/block/blk-lib.c b/block/blk-lib.c
index 0d1811e57ac704..e90614fd8d6a42 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -64,7 +64,7 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 		return -EINVAL;
 
 	/* In case the discard request is in a partition */
-	if (bdev->bd_partno)
+	if (bdev_is_partition(bdev))
 		part_offset = bdev->bd_part->start_sect;
 
 	while (nr_sects) {
diff --git a/block/ioctl.c b/block/ioctl.c
index bdb3bbb253d9f8..e4af3df9d28a68 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -23,7 +23,7 @@ static int blkpg_do_ioctl(struct block_device *bdev,
 		return -EACCES;
 	if (copy_from_user(&p, upart, sizeof(struct blkpg_partition)))
 		return -EFAULT;
-	if (bdev != bdev->bd_contains)
+	if (bdev_is_partition(bdev))
 		return -EINVAL;
 
 	if (p.pno <= 0)
@@ -94,7 +94,7 @@ static int blkdev_reread_part(struct block_device *bdev)
 {
 	int ret;
 
-	if (!disk_part_scan_enabled(bdev->bd_disk) || bdev != bdev->bd_contains)
+	if (!disk_part_scan_enabled(bdev->bd_disk) || bdev_is_partition(bdev))
 		return -EINVAL;
 	if (!capable(CAP_SYS_ADMIN))
 		return -EACCES;
diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index ef722f04f88a93..3bb4571385ce21 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -854,7 +854,7 @@ EXPORT_SYMBOL(scsi_cmd_ioctl);
 
 int scsi_verify_blk_ioctl(struct block_device *bd, unsigned int cmd)
 {
-	if (bd && bd == bd->bd_contains)
+	if (bd && !bdev_is_partition(bd))
 		return 0;
 
 	if (capable(CAP_SYS_RAWIO))
diff --git a/drivers/ide/ide-ioctls.c b/drivers/ide/ide-ioctls.c
index 09491098047bff..58994da10c0664 100644
--- a/drivers/ide/ide-ioctls.c
+++ b/drivers/ide/ide-ioctls.c
@@ -49,7 +49,7 @@ int ide_setting_ioctl(ide_drive_t *drive, struct block_device *bdev,
 	return err >= 0 ? put_user_long(err, arg) : err;
 
 set_val:
-	if (bdev != bdev->bd_contains)
+	if (bdev_is_partition(bdev))
 		err = -EINVAL;
 	else {
 		if (!capable(CAP_SYS_ADMIN))
@@ -257,7 +257,7 @@ int generic_ide_ioctl(ide_drive_t *drive, struct block_device *bdev,
 	switch (cmd) {
 	case HDIO_OBSOLETE_IDENTITY:
 	case HDIO_GET_IDENTITY:
-		if (bdev != bdev->bd_contains)
+		if (bdev_is_partition(bdev))
 			return -EINVAL;
 		return ide_get_identity_ioctl(drive, cmd, argp);
 	case HDIO_GET_NICE:
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 5edc3079e7c199..af156256e511ff 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -903,7 +903,7 @@ static int device_is_rq_stackable(struct dm_target *ti, struct dm_dev *dev,
 	struct request_queue *q = bdev_get_queue(bdev);
 
 	/* request-based cannot stack on partitions! */
-	if (bdev != bdev->bd_contains)
+	if (bdev_is_partition(bdev))
 		return false;
 
 	return queue_is_mq(q);
diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index fa313b63413547..8d3df0be0355ce 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -723,7 +723,7 @@ static int mmc_blk_check_blkdev(struct block_device *bdev)
 	 * whole block device, not on a partition.  This prevents overspray
 	 * between sibling partitions.
 	 */
-	if ((!capable(CAP_SYS_RAWIO)) || (bdev != bdev->bd_contains))
+	if (!capable(CAP_SYS_RAWIO) || bdev_is_partition(bdev))
 		return -EPERM;
 	return 0;
 }
diff --git a/drivers/s390/block/dasd_ioctl.c b/drivers/s390/block/dasd_ioctl.c
index faaf5596e31c12..cb6427fb9f3d16 100644
--- a/drivers/s390/block/dasd_ioctl.c
+++ b/drivers/s390/block/dasd_ioctl.c
@@ -277,7 +277,7 @@ dasd_ioctl_format(struct block_device *bdev, void __user *argp)
 		dasd_put_device(base);
 		return -EFAULT;
 	}
-	if (bdev != bdev->bd_contains) {
+	if (bdev_is_partition(bdev)) {
 		pr_warn("%s: The specified DASD is a partition and cannot be formatted\n",
 			dev_name(&base->cdev->dev));
 		dasd_put_device(base);
@@ -304,7 +304,7 @@ static int dasd_ioctl_check_format(struct block_device *bdev, void __user *argp)
 	base = dasd_device_from_gendisk(bdev->bd_disk);
 	if (!base)
 		return -ENODEV;
-	if (bdev != bdev->bd_contains) {
+	if (bdev_is_partition(bdev)) {
 		pr_warn("%s: The specified DASD is a partition and cannot be checked\n",
 			dev_name(&base->cdev->dev));
 		rc = -EINVAL;
@@ -362,7 +362,7 @@ static int dasd_ioctl_release_space(struct block_device *bdev, void __user *argp
 		rc = -EROFS;
 		goto out_err;
 	}
-	if (bdev != bdev->bd_contains) {
+	if (bdev_is_partition(bdev)) {
 		pr_warn("%s: The specified DASD is a partition and tracks cannot be released\n",
 			dev_name(&base->cdev->dev));
 		rc = -EINVAL;
@@ -540,7 +540,7 @@ dasd_ioctl_set_ro(struct block_device *bdev, void __user *argp)
 
 	if (!capable(CAP_SYS_ADMIN))
 		return -EACCES;
-	if (bdev != bdev->bd_contains)
+	if (bdev_is_partition(bdev))
 		// ro setting is not allowed for partitions
 		return -EINVAL;
 	if (get_user(intval, (int __user *)argp))
diff --git a/fs/nfsd/blocklayout.c b/fs/nfsd/blocklayout.c
index 311e5ce80cfc27..a07c39c94bbd03 100644
--- a/fs/nfsd/blocklayout.c
+++ b/fs/nfsd/blocklayout.c
@@ -170,7 +170,7 @@ nfsd4_block_proc_getdeviceinfo(struct super_block *sb,
 		struct nfs4_client *clp,
 		struct nfsd4_getdeviceinfo *gdp)
 {
-	if (sb->s_bdev != sb->s_bdev->bd_contains)
+	if (bdev_is_partition(sb->s_bdev))
 		return nfserr_inval;
 	return nfserrno(nfsd4_block_get_device_info_simple(sb, gdp));
 }
@@ -382,7 +382,7 @@ nfsd4_scsi_proc_getdeviceinfo(struct super_block *sb,
 		struct nfs4_client *clp,
 		struct nfsd4_getdeviceinfo *gdp)
 {
-	if (sb->s_bdev != sb->s_bdev->bd_contains)
+	if (bdev_is_partition(sb->s_bdev))
 		return nfserr_inval;
 	return nfserrno(nfsd4_block_get_device_info_scsi(sb, clp, gdp));
 }
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 7575fa0aae6e5c..0006a78ebc5dde 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1341,6 +1341,11 @@ static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
 
 extern int blk_verify_command(unsigned char *cmd, fmode_t mode);
 
+static inline bool bdev_is_partition(struct block_device *bdev)
+{
+	return bdev->bd_partno;
+}
+
 enum blk_default_limits {
 	BLK_MAX_SEGMENTS	= 128,
 	BLK_SAFE_MAX_SECTORS	= 255,
@@ -1457,7 +1462,7 @@ static inline int bdev_alignment_offset(struct block_device *bdev)
 
 	if (q->limits.misaligned)
 		return -1;
-	if (bdev != bdev->bd_contains)
+	if (bdev_is_partition(bdev))
 		return queue_limit_alignment_offset(&q->limits,
 				bdev->bd_part->start_sect);
 	return q->limits.alignment_offset;
@@ -1498,7 +1503,7 @@ static inline int bdev_discard_alignment(struct block_device *bdev)
 {
 	struct request_queue *q = bdev_get_queue(bdev);
 
-	if (bdev != bdev->bd_contains)
+	if (bdev_is_partition(bdev))
 		return queue_limit_discard_alignment(&q->limits,
 				bdev->bd_part->start_sect);
 	return q->limits.discard_alignment;
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 4b3a42fc3b24f1..157758a88773b9 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -527,7 +527,7 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
 	 * and scsi-generic block devices we create a temporary new debugfs
 	 * directory that will be removed once the trace ends.
 	 */
-	if (bdev && bdev == bdev->bd_contains)
+	if (bdev && !bdev_is_partition(bdev))
 		dir = q->debugfs_dir;
 	else
 		bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
-- 
2.28.0

Re: [PATCH 2/9] block: add a bdev_is_partition helper

[Ulf Hansson]

On Thu, 3 Sep 2020 at 07:42, Christoph Hellwig <hch@lst.de> wrote:
>
> Add a littler helper to make the somewhat arcane bd_contains checks a
> little more obvious.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Not sure why we have both "bd_contains" and "bd_partno", nevertheless,
feel free to add:

Acked-by: Ulf Hansson <ulf.hansson@linaro.org>

Kind regards
Uffe

> ---
>  block/blk-lib.c                 | 2 +-
>  block/ioctl.c                   | 4 ++--
>  block/scsi_ioctl.c              | 2 +-
>  drivers/ide/ide-ioctls.c        | 4 ++--
>  drivers/md/dm-table.c           | 2 +-
>  drivers/mmc/core/block.c        | 2 +-
>  drivers/s390/block/dasd_ioctl.c | 8 ++++----
>  fs/nfsd/blocklayout.c           | 4 ++--
>  include/linux/blkdev.h          | 9 +++++++--
>  kernel/trace/blktrace.c         | 2 +-
>  10 files changed, 22 insertions(+), 17 deletions(-)
>
> diff --git a/block/blk-lib.c b/block/blk-lib.c
> index 0d1811e57ac704..e90614fd8d6a42 100644
> --- a/block/blk-lib.c
> +++ b/block/blk-lib.c
> @@ -64,7 +64,7 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
>                 return -EINVAL;
>
>         /* In case the discard request is in a partition */
> -       if (bdev->bd_partno)
> +       if (bdev_is_partition(bdev))
>                 part_offset = bdev->bd_part->start_sect;
>
>         while (nr_sects) {
> diff --git a/block/ioctl.c b/block/ioctl.c
> index bdb3bbb253d9f8..e4af3df9d28a68 100644
> --- a/block/ioctl.c
> +++ b/block/ioctl.c
> @@ -23,7 +23,7 @@ static int blkpg_do_ioctl(struct block_device *bdev,
>                 return -EACCES;
>         if (copy_from_user(&p, upart, sizeof(struct blkpg_partition)))
>                 return -EFAULT;
> -       if (bdev != bdev->bd_contains)
> +       if (bdev_is_partition(bdev))
>                 return -EINVAL;
>
>         if (p.pno <= 0)
> @@ -94,7 +94,7 @@ static int blkdev_reread_part(struct block_device *bdev)
>  {
>         int ret;
>
> -       if (!disk_part_scan_enabled(bdev->bd_disk) || bdev != bdev->bd_contains)
> +       if (!disk_part_scan_enabled(bdev->bd_disk) || bdev_is_partition(bdev))
>                 return -EINVAL;
>         if (!capable(CAP_SYS_ADMIN))
>                 return -EACCES;
> diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
> index ef722f04f88a93..3bb4571385ce21 100644
> --- a/block/scsi_ioctl.c
> +++ b/block/scsi_ioctl.c
> @@ -854,7 +854,7 @@ EXPORT_SYMBOL(scsi_cmd_ioctl);
>
>  int scsi_verify_blk_ioctl(struct block_device *bd, unsigned int cmd)
>  {
> -       if (bd && bd == bd->bd_contains)
> +       if (bd && !bdev_is_partition(bd))
>                 return 0;
>
>         if (capable(CAP_SYS_RAWIO))
> diff --git a/drivers/ide/ide-ioctls.c b/drivers/ide/ide-ioctls.c
> index 09491098047bff..58994da10c0664 100644
> --- a/drivers/ide/ide-ioctls.c
> +++ b/drivers/ide/ide-ioctls.c
> @@ -49,7 +49,7 @@ int ide_setting_ioctl(ide_drive_t *drive, struct block_device *bdev,
>         return err >= 0 ? put_user_long(err, arg) : err;
>
>  set_val:
> -       if (bdev != bdev->bd_contains)
> +       if (bdev_is_partition(bdev))
>                 err = -EINVAL;
>         else {
>                 if (!capable(CAP_SYS_ADMIN))
> @@ -257,7 +257,7 @@ int generic_ide_ioctl(ide_drive_t *drive, struct block_device *bdev,
>         switch (cmd) {
>         case HDIO_OBSOLETE_IDENTITY:
>         case HDIO_GET_IDENTITY:
> -               if (bdev != bdev->bd_contains)
> +               if (bdev_is_partition(bdev))
>                         return -EINVAL;
>                 return ide_get_identity_ioctl(drive, cmd, argp);
>         case HDIO_GET_NICE:
> diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
> index 5edc3079e7c199..af156256e511ff 100644
> --- a/drivers/md/dm-table.c
> +++ b/drivers/md/dm-table.c
> @@ -903,7 +903,7 @@ static int device_is_rq_stackable(struct dm_target *ti, struct dm_dev *dev,
>         struct request_queue *q = bdev_get_queue(bdev);
>
>         /* request-based cannot stack on partitions! */
> -       if (bdev != bdev->bd_contains)
> +       if (bdev_is_partition(bdev))
>                 return false;
>
>         return queue_is_mq(q);
> diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
> index fa313b63413547..8d3df0be0355ce 100644
> --- a/drivers/mmc/core/block.c
> +++ b/drivers/mmc/core/block.c
> @@ -723,7 +723,7 @@ static int mmc_blk_check_blkdev(struct block_device *bdev)
>          * whole block device, not on a partition.  This prevents overspray
>          * between sibling partitions.
>          */
> -       if ((!capable(CAP_SYS_RAWIO)) || (bdev != bdev->bd_contains))
> +       if (!capable(CAP_SYS_RAWIO) || bdev_is_partition(bdev))
>                 return -EPERM;
>         return 0;
>  }
> diff --git a/drivers/s390/block/dasd_ioctl.c b/drivers/s390/block/dasd_ioctl.c
> index faaf5596e31c12..cb6427fb9f3d16 100644
> --- a/drivers/s390/block/dasd_ioctl.c
> +++ b/drivers/s390/block/dasd_ioctl.c
> @@ -277,7 +277,7 @@ dasd_ioctl_format(struct block_device *bdev, void __user *argp)
>                 dasd_put_device(base);
>                 return -EFAULT;
>         }
> -       if (bdev != bdev->bd_contains) {
> +       if (bdev_is_partition(bdev)) {
>                 pr_warn("%s: The specified DASD is a partition and cannot be formatted\n",
>                         dev_name(&base->cdev->dev));
>                 dasd_put_device(base);
> @@ -304,7 +304,7 @@ static int dasd_ioctl_check_format(struct block_device *bdev, void __user *argp)
>         base = dasd_device_from_gendisk(bdev->bd_disk);
>         if (!base)
>                 return -ENODEV;
> -       if (bdev != bdev->bd_contains) {
> +       if (bdev_is_partition(bdev)) {
>                 pr_warn("%s: The specified DASD is a partition and cannot be checked\n",
>                         dev_name(&base->cdev->dev));
>                 rc = -EINVAL;
> @@ -362,7 +362,7 @@ static int dasd_ioctl_release_space(struct block_device *bdev, void __user *argp
>                 rc = -EROFS;
>                 goto out_err;
>         }
> -       if (bdev != bdev->bd_contains) {
> +       if (bdev_is_partition(bdev)) {
>                 pr_warn("%s: The specified DASD is a partition and tracks cannot be released\n",
>                         dev_name(&base->cdev->dev));
>                 rc = -EINVAL;
> @@ -540,7 +540,7 @@ dasd_ioctl_set_ro(struct block_device *bdev, void __user *argp)
>
>         if (!capable(CAP_SYS_ADMIN))
>                 return -EACCES;
> -       if (bdev != bdev->bd_contains)
> +       if (bdev_is_partition(bdev))
>                 // ro setting is not allowed for partitions
>                 return -EINVAL;
>         if (get_user(intval, (int __user *)argp))
> diff --git a/fs/nfsd/blocklayout.c b/fs/nfsd/blocklayout.c
> index 311e5ce80cfc27..a07c39c94bbd03 100644
> --- a/fs/nfsd/blocklayout.c
> +++ b/fs/nfsd/blocklayout.c
> @@ -170,7 +170,7 @@ nfsd4_block_proc_getdeviceinfo(struct super_block *sb,
>                 struct nfs4_client *clp,
>                 struct nfsd4_getdeviceinfo *gdp)
>  {
> -       if (sb->s_bdev != sb->s_bdev->bd_contains)
> +       if (bdev_is_partition(sb->s_bdev))
>                 return nfserr_inval;
>         return nfserrno(nfsd4_block_get_device_info_simple(sb, gdp));
>  }
> @@ -382,7 +382,7 @@ nfsd4_scsi_proc_getdeviceinfo(struct super_block *sb,
>                 struct nfs4_client *clp,
>                 struct nfsd4_getdeviceinfo *gdp)
>  {
> -       if (sb->s_bdev != sb->s_bdev->bd_contains)
> +       if (bdev_is_partition(sb->s_bdev))
>                 return nfserr_inval;
>         return nfserrno(nfsd4_block_get_device_info_scsi(sb, clp, gdp));
>  }
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index 7575fa0aae6e5c..0006a78ebc5dde 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -1341,6 +1341,11 @@ static inline int sb_issue_zeroout(struct super_block *sb, sector_t block,
>
>  extern int blk_verify_command(unsigned char *cmd, fmode_t mode);
>
> +static inline bool bdev_is_partition(struct block_device *bdev)
> +{
> +       return bdev->bd_partno;
> +}
> +
>  enum blk_default_limits {
>         BLK_MAX_SEGMENTS        = 128,
>         BLK_SAFE_MAX_SECTORS    = 255,
> @@ -1457,7 +1462,7 @@ static inline int bdev_alignment_offset(struct block_device *bdev)
>
>         if (q->limits.misaligned)
>                 return -1;
> -       if (bdev != bdev->bd_contains)
> +       if (bdev_is_partition(bdev))
>                 return queue_limit_alignment_offset(&q->limits,
>                                 bdev->bd_part->start_sect);
>         return q->limits.alignment_offset;
> @@ -1498,7 +1503,7 @@ static inline int bdev_discard_alignment(struct block_device *bdev)
>  {
>         struct request_queue *q = bdev_get_queue(bdev);
>
> -       if (bdev != bdev->bd_contains)
> +       if (bdev_is_partition(bdev))
>                 return queue_limit_discard_alignment(&q->limits,
>                                 bdev->bd_part->start_sect);
>         return q->limits.discard_alignment;
> diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
> index 4b3a42fc3b24f1..157758a88773b9 100644
> --- a/kernel/trace/blktrace.c
> +++ b/kernel/trace/blktrace.c
> @@ -527,7 +527,7 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
>          * and scsi-generic block devices we create a temporary new debugfs
>          * directory that will be removed once the trace ends.
>          */
> -       if (bdev && bdev == bdev->bd_contains)
> +       if (bdev && !bdev_is_partition(bdev))
>                 dir = q->debugfs_dir;
>         else
>                 bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
> --
> 2.28.0
>

Re: [PATCH 2/9] block: add a bdev_is_partition helper

[Christoph Hellwig]

On Thu, Sep 03, 2020 at 10:19:34AM +0200, Ulf Hansson wrote:
> On Thu, 3 Sep 2020 at 07:42, Christoph Hellwig <hch@lst.de> wrote:
> >
> > Add a littler helper to make the somewhat arcane bd_contains checks a
> > little more obvious.
> >
> > Signed-off-by: Christoph Hellwig <hch@lst.de>
> 
> Not sure why we have both "bd_contains" and "bd_partno", nevertheless,
> feel free to add:

Right now both are needed for how blkdev_get/put work.  But I plan to
eventual kill off bd_contains after some major surgery to that code.

[PATCH 3/9] md: compare bd_disk instead of bd_contains

[Christoph Hellwig]

To check for partitions of the same disk bd_contains works as well, but
bd_disk is way more obvious.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/md/md.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 9562ef598ae1f4..3f33562d10d6f5 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -2322,8 +2322,7 @@ static int match_mddev_units(struct mddev *mddev1, struct mddev *mddev2)
 			    test_bit(Journal, &rdev2->flags) ||
 			    rdev2->raid_disk == -1)
 				continue;
-			if (rdev->bdev->bd_contains ==
-			    rdev2->bdev->bd_contains) {
+			if (rdev->bdev->bd_disk == rdev2->bdev->bd_disk) {
 				rcu_read_unlock();
 				return 1;
 			}
@@ -5944,8 +5943,8 @@ int md_run(struct mddev *mddev)
 		rdev_for_each(rdev, mddev)
 			rdev_for_each(rdev2, mddev) {
 				if (rdev < rdev2 &&
-				    rdev->bdev->bd_contains ==
-				    rdev2->bdev->bd_contains) {
+				    rdev->bdev->bd_disk ==
+				    rdev2->bdev->bd_disk) {
 					pr_warn("%s: WARNING: %s appears to be on the same physical disk as %s.\n",
 						mdname(mddev),
 						bdevname(rdev->bdev,b),
-- 
2.28.0

Re: [PATCH 3/9] md: compare bd_disk instead of bd_contains

[Song Liu]

On Wed, Sep 2, 2020 at 10:43 PM Christoph Hellwig <hch@lst.de> wrote:
>
> To check for partitions of the same disk bd_contains works as well, but
> bd_disk is way more obvious.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Acked-by: Song Liu <song@kernel.org>

> ---
>  drivers/md/md.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 9562ef598ae1f4..3f33562d10d6f5 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -2322,8 +2322,7 @@ static int match_mddev_units(struct mddev *mddev1, struct mddev *mddev2)
>                             test_bit(Journal, &rdev2->flags) ||
>                             rdev2->raid_disk == -1)
>                                 continue;
> -                       if (rdev->bdev->bd_contains ==
> -                           rdev2->bdev->bd_contains) {
> +                       if (rdev->bdev->bd_disk == rdev2->bdev->bd_disk) {
>                                 rcu_read_unlock();
>                                 return 1;
>                         }
> @@ -5944,8 +5943,8 @@ int md_run(struct mddev *mddev)
>                 rdev_for_each(rdev, mddev)
>                         rdev_for_each(rdev2, mddev) {
>                                 if (rdev < rdev2 &&
> -                                   rdev->bdev->bd_contains ==
> -                                   rdev2->bdev->bd_contains) {
> +                                   rdev->bdev->bd_disk ==
> +                                   rdev2->bdev->bd_disk) {
>                                         pr_warn("%s: WARNING: %s appears to be on the same physical disk as %s.\n",
>                                                 mdname(mddev),
>                                                 bdevname(rdev->bdev,b),
> --
> 2.28.0
>

[PATCH 4/9] md: don't detour through bd_contains for the gendisk

[Christoph Hellwig]

bd_disk is set on all block devices, including those for partitions.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/md/md.c | 2 +-
 drivers/md/md.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 3f33562d10d6f5..5a0fd93769a70e 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -8444,7 +8444,7 @@ static int is_mddev_idle(struct mddev *mddev, int init)
 	idle = 1;
 	rcu_read_lock();
 	rdev_for_each_rcu(rdev, mddev) {
-		struct gendisk *disk = rdev->bdev->bd_contains->bd_disk;
+		struct gendisk *disk = rdev->bdev->bd_disk;
 		curr_events = (int)part_stat_read_accum(&disk->part0, sectors) -
 			      atomic_read(&disk->sync_io);
 		/* sync IO will cause sync_io to increase before the disk_stats
diff --git a/drivers/md/md.h b/drivers/md/md.h
index f9e2ccdd22c478..2175a5ac4f7c68 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -551,7 +551,7 @@ extern void mddev_unlock(struct mddev *mddev);
 
 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
 {
-	atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
+	atomic_add(nr_sectors, &bdev->bd_disk->sync_io);
 }
 
 static inline void md_sync_acct_bio(struct bio *bio, unsigned long nr_sectors)
-- 
2.28.0

Re: [PATCH 4/9] md: don't detour through bd_contains for the gendisk

[Song Liu]

On Wed, Sep 2, 2020 at 10:43 PM Christoph Hellwig <hch@lst.de> wrote:
>
> bd_disk is set on all block devices, including those for partitions.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Acked-by: Song Liu <song@kernel.org>

> ---
>  drivers/md/md.c | 2 +-
>  drivers/md/md.h | 2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 3f33562d10d6f5..5a0fd93769a70e 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -8444,7 +8444,7 @@ static int is_mddev_idle(struct mddev *mddev, int init)
>         idle = 1;
>         rcu_read_lock();
>         rdev_for_each_rcu(rdev, mddev) {
> -               struct gendisk *disk = rdev->bdev->bd_contains->bd_disk;
> +               struct gendisk *disk = rdev->bdev->bd_disk;
>                 curr_events = (int)part_stat_read_accum(&disk->part0, sectors) -
>                               atomic_read(&disk->sync_io);
>                 /* sync IO will cause sync_io to increase before the disk_stats
> diff --git a/drivers/md/md.h b/drivers/md/md.h
> index f9e2ccdd22c478..2175a5ac4f7c68 100644
> --- a/drivers/md/md.h
> +++ b/drivers/md/md.h
> @@ -551,7 +551,7 @@ extern void mddev_unlock(struct mddev *mddev);
>
>  static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
>  {
> -       atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
> +       atomic_add(nr_sectors, &bdev->bd_disk->sync_io);
>  }
>
>  static inline void md_sync_acct_bio(struct bio *bio, unsigned long nr_sectors)
> --
> 2.28.0
>

[PATCH 5/9] drbd: don't detour through bd_contains for the gendisk

[Christoph Hellwig]

bd_disk is set on all block devices, including those for partitions.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/block/drbd/drbd_receiver.c | 2 +-
 drivers/block/drbd/drbd_worker.c   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 422363daa6180b..2d16fb0905999d 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -2789,7 +2789,7 @@ bool drbd_rs_should_slow_down(struct drbd_device *device, sector_t sector,
 
 bool drbd_rs_c_min_rate_throttle(struct drbd_device *device)
 {
-	struct gendisk *disk = device->ldev->backing_bdev->bd_contains->bd_disk;
+	struct gendisk *disk = device->ldev->backing_bdev->bd_disk;
 	unsigned long db, dt, dbdt;
 	unsigned int c_min_rate;
 	int curr_events;
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 7c903de5c4e103..9107b109ba7bcb 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -1672,7 +1672,7 @@ void drbd_resync_after_changed(struct drbd_device *device)
 
 void drbd_rs_controller_reset(struct drbd_device *device)
 {
-	struct gendisk *disk = device->ldev->backing_bdev->bd_contains->bd_disk;
+	struct gendisk *disk = device->ldev->backing_bdev->bd_disk;
 	struct fifo_buffer *plan;
 
 	atomic_set(&device->rs_sect_in, 0);
-- 
2.28.0

[PATCH 6/9] drbd: don't set ->bd_contains

[Christoph Hellwig]

The ->bd_contains field is set by __blkdev_get and drivers have no
business manipulating it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/block/drbd/drbd_main.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 04b6bde9419d2a..bd8b129196d49a 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2766,8 +2766,6 @@ enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsig
 	disk->private_data = device;
 
 	device->this_bdev = bdget(MKDEV(DRBD_MAJOR, minor));
-	/* we have no partitions. we contain only ourselves. */
-	device->this_bdev->bd_contains = device->this_bdev;
 
 	blk_queue_write_cache(q, true, true);
 	/* Setting the max_hw_sectors to an odd value of 8kibyte here
-- 
2.28.0

[PATCH 7/9] target/iblock: fix holder printing in iblock_show_configfs_dev_params

[Christoph Hellwig]

bd_contains is never NULL for an open block device.  In addition ibd_bd
is always set to a block device that was exclusively opened by the
target code, so the holder is guranteed to be ib_dev as well.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/target/target_core_iblock.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index 1c181d31f4c872..f2bd2e207e0b36 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -611,9 +611,8 @@ static ssize_t iblock_show_configfs_dev_params(struct se_device *dev, char *b)
 	bl += sprintf(b + bl, "        ");
 	if (bd) {
 		bl += sprintf(b + bl, "Major: %d Minor: %d  %s\n",
-			MAJOR(bd->bd_dev), MINOR(bd->bd_dev), (!bd->bd_contains) ?
-			"" : (bd->bd_holder == ib_dev) ?
-			"CLAIMED: IBLOCK" : "CLAIMED: OS");
+			MAJOR(bd->bd_dev), MINOR(bd->bd_dev),
+			"CLAIMED: IBLOCK");
 	} else {
 		bl += sprintf(b + bl, "Major: 0 Minor: 0\n");
 	}
-- 
2.28.0

[PATCH 8/9] block: use bd_partno in bdevname

[Christoph Hellwig]

No need to go through the hd_struct to find the partition number.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/genhd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/genhd.c b/block/genhd.c
index 081f1039d9367f..771aa56b1a8c3d 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -85,7 +85,7 @@ char *disk_name(struct gendisk *hd, int partno, char *buf)
 
 const char *bdevname(struct block_device *bdev, char *buf)
 {
-	return disk_name(bdev->bd_disk, bdev->bd_part->partno, buf);
+	return disk_name(bdev->bd_disk, bdev->bd_partno, buf);
 }
 EXPORT_SYMBOL(bdevname);
 
-- 
2.28.0

[PATCH 9/9] vsprintf: use bd_partno in bdev_name

[Christoph Hellwig]

No need to go through the hd_struct to find the partition number.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 lib/vsprintf.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index afb9521ddf9197..14c9a6af1b239a 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -940,13 +940,13 @@ char *bdev_name(char *buf, char *end, struct block_device *bdev,
 
 	hd = bdev->bd_disk;
 	buf = string(buf, end, hd->disk_name, spec);
-	if (bdev->bd_part->partno) {
+	if (bdev->bd_partno) {
 		if (isdigit(hd->disk_name[strlen(hd->disk_name)-1])) {
 			if (buf < end)
 				*buf = 'p';
 			buf++;
 		}
-		buf = number(buf, end, bdev->bd_part->partno, spec);
+		buf = number(buf, end, bdev->bd_partno, spec);
 	}
 	return buf;
 }
-- 
2.28.0

Re: clean up is partition checks

[Christoph Hellwig]

Jens,

can you pick this series up?

Re: clean up is partition checks

[Jens Axboe]

On 9/2/20 11:40 PM, Christoph Hellwig wrote:
> Hi Jens,
> 
> this series add a new helepr to check if a struct block_device represents
> a parition, and removes most direct access to ->bd_contained from
> drivers.

Applied, thanks.

-- 
Jens Axboe