[5/5] block: remove (__)blkdev_reread_part as an exported API
diff mbox series

Message ID 20191106151439.30056-6-hch@lst.de
State New
Headers show
Series
  • [1/5] block: refactor rescan_partitions
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Commit Message

Christoph Hellwig Nov. 6, 2019, 3:14 p.m. UTC
In general drivers should never mess with partition tables directly.
Unfortunately s390 and loop do for somewhat historic reasons, but they
can use bdev_disk_changed directly instead when we export it as they
satisfy the sanity checks we have in __blkdev_reread_part.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/ioctl.c                   | 35 +++++----------------------------
 drivers/block/loop.c            | 13 +++++++-----
 drivers/s390/block/dasd_genhd.c |  4 +++-
 fs/block_dev.c                  |  7 +++++++
 include/linux/fs.h              |  2 --
 5 files changed, 23 insertions(+), 38 deletions(-)

Comments

Stefan Haberland Nov. 7, 2019, 1:27 p.m. UTC | #1
On 06.11.19 16:14, Christoph Hellwig wrote:
> In general drivers should never mess with partition tables directly.
> Unfortunately s390 and loop do for somewhat historic reasons, but they
> can use bdev_disk_changed directly instead when we export it as they
> satisfy the sanity checks we have in __blkdev_reread_part.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Hi,

tested (the whole patchset) with DASD on s390 and for the DASD part:

Reviewed-by: Stefan Haberland <sth@linux.ibm.com>
Jan Kara Nov. 14, 2019, 2:24 p.m. UTC | #2
On Wed 06-11-19 16:14:39, Christoph Hellwig wrote:
> In general drivers should never mess with partition tables directly.
> Unfortunately s390 and loop do for somewhat historic reasons, but they
> can use bdev_disk_changed directly instead when we export it as they
> satisfy the sanity checks we have in __blkdev_reread_part.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Looks good to me. You can add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  block/ioctl.c                   | 35 +++++----------------------------
>  drivers/block/loop.c            | 13 +++++++-----
>  drivers/s390/block/dasd_genhd.c |  4 +++-
>  fs/block_dev.c                  |  7 +++++++
>  include/linux/fs.h              |  2 --
>  5 files changed, 23 insertions(+), 38 deletions(-)
> 
> diff --git a/block/ioctl.c b/block/ioctl.c
> index 52380c337078..2ed907ef0f01 100644
> --- a/block/ioctl.c
> +++ b/block/ioctl.c
> @@ -155,46 +155,21 @@ static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user
>  	}
>  }
>  
> -/*
> - * This is an exported API for the block driver, and will not
> - * acquire bd_mutex. This API should be used in case that
> - * caller has held bd_mutex already.
> - */
> -int __blkdev_reread_part(struct block_device *bdev)
> +static int blkdev_reread_part(struct block_device *bdev)
>  {
> +	int ret;
> +
>  	if (!disk_part_scan_enabled(bdev->bd_disk) || bdev != bdev->bd_contains)
>  		return -EINVAL;
>  	if (!capable(CAP_SYS_ADMIN))
>  		return -EACCES;
>  
> -	lockdep_assert_held(&bdev->bd_mutex);
> -
> -	return bdev_disk_changed(bdev, false);
> -}
> -EXPORT_SYMBOL(__blkdev_reread_part);
> -
> -/*
> - * This is an exported API for the block driver, and will
> - * try to acquire bd_mutex. If bd_mutex has been held already
> - * in current context, please call __blkdev_reread_part().
> - *
> - * Make sure the held locks in current context aren't required
> - * in open()/close() handler and I/O path for avoiding ABBA deadlock:
> - * - bd_mutex is held before calling block driver's open/close
> - *   handler
> - * - reading partition table may submit I/O to the block device
> - */
> -int blkdev_reread_part(struct block_device *bdev)
> -{
> -	int res;
> -
>  	mutex_lock(&bdev->bd_mutex);
> -	res = __blkdev_reread_part(bdev);
> +	ret = bdev_disk_changed(bdev, false);
>  	mutex_unlock(&bdev->bd_mutex);
>  
> -	return res;
> +	return ret;
>  }
> -EXPORT_SYMBOL(blkdev_reread_part);
>  
>  static int blk_ioctl_discard(struct block_device *bdev, fmode_t mode,
>  		unsigned long arg, unsigned long flags)
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index f6f77eaa7217..64b16abee280 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -630,7 +630,9 @@ static void loop_reread_partitions(struct loop_device *lo,
>  {
>  	int rc;
>  
> -	rc = blkdev_reread_part(bdev);
> +	mutex_lock(&bdev->bd_mutex);
> +	rc = bdev_disk_changed(bdev, false);
> +	mutex_unlock(&bdev->bd_mutex);
>  	if (rc)
>  		pr_warn("%s: partition scan of loop%d (%s) failed (rc=%d)\n",
>  			__func__, lo->lo_number, lo->lo_file_name, rc);
> @@ -1154,10 +1156,11 @@ static int __loop_clr_fd(struct loop_device *lo, bool release)
>  		 * must be at least one and it can only become zero when the
>  		 * current holder is released.
>  		 */
> -		if (release)
> -			err = __blkdev_reread_part(bdev);
> -		else
> -			err = blkdev_reread_part(bdev);
> +		if (!release)
> +			mutex_lock(&bdev->bd_mutex);
> +		err = bdev_disk_changed(bdev, false);
> +		if (!release)
> +			mutex_unlock(&bdev->bd_mutex);
>  		if (err)
>  			pr_warn("%s: partition scan of loop%d failed (rc=%d)\n",
>  				__func__, lo_number, err);
> diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c
> index 5542d9eadfe0..7d079154f849 100644
> --- a/drivers/s390/block/dasd_genhd.c
> +++ b/drivers/s390/block/dasd_genhd.c
> @@ -116,7 +116,9 @@ int dasd_scan_partitions(struct dasd_block *block)
>  		return -ENODEV;
>  	}
>  
> -	rc = blkdev_reread_part(bdev);
> +	mutex_lock(&bdev->bd_mutex);
> +	rc = bdev_disk_changed(bdev, false);
> +	mutex_unlock(&bdev->bd_mutex);
>  	if (rc)
>  		DBF_DEV_EVENT(DBF_ERR, block->base,
>  				"scan partitions error, rc %d", rc);
> diff --git a/fs/block_dev.c b/fs/block_dev.c
> index ae16466a67f7..9558a2f064b1 100644
> --- a/fs/block_dev.c
> +++ b/fs/block_dev.c
> @@ -1513,6 +1513,8 @@ int bdev_disk_changed(struct block_device *bdev, bool invalidate)
>  	struct gendisk *disk = bdev->bd_disk;
>  	int ret;
>  
> +	lockdep_assert_held(&bdev->bd_mutex);
> +
>  rescan:
>  	ret = blk_drop_partitions(disk, bdev);
>  	if (ret)
> @@ -1540,6 +1542,11 @@ int bdev_disk_changed(struct block_device *bdev, bool invalidate)
>  
>  	return ret;
>  }
> +/*
> + * Only exported for for loop and dasd for historic reasons.  Don't use in new
> + * code!
> + */
> +EXPORT_SYMBOL_GPL(bdev_disk_changed);
>  
>  /*
>   * bd_mutex locking:
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index d233dd661df7..ae6c5c37f3ae 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -2632,8 +2632,6 @@ extern void bd_finish_claiming(struct block_device *bdev,
>  extern void bd_abort_claiming(struct block_device *bdev,
>  			      struct block_device *whole, void *holder);
>  extern void blkdev_put(struct block_device *bdev, fmode_t mode);
> -extern int __blkdev_reread_part(struct block_device *bdev);
> -extern int blkdev_reread_part(struct block_device *bdev);
>  
>  #ifdef CONFIG_SYSFS
>  extern int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk);
> -- 
> 2.20.1
>

Patch
diff mbox series

diff --git a/block/ioctl.c b/block/ioctl.c
index 52380c337078..2ed907ef0f01 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -155,46 +155,21 @@  static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user
 	}
 }
 
-/*
- * This is an exported API for the block driver, and will not
- * acquire bd_mutex. This API should be used in case that
- * caller has held bd_mutex already.
- */
-int __blkdev_reread_part(struct block_device *bdev)
+static int blkdev_reread_part(struct block_device *bdev)
 {
+	int ret;
+
 	if (!disk_part_scan_enabled(bdev->bd_disk) || bdev != bdev->bd_contains)
 		return -EINVAL;
 	if (!capable(CAP_SYS_ADMIN))
 		return -EACCES;
 
-	lockdep_assert_held(&bdev->bd_mutex);
-
-	return bdev_disk_changed(bdev, false);
-}
-EXPORT_SYMBOL(__blkdev_reread_part);
-
-/*
- * This is an exported API for the block driver, and will
- * try to acquire bd_mutex. If bd_mutex has been held already
- * in current context, please call __blkdev_reread_part().
- *
- * Make sure the held locks in current context aren't required
- * in open()/close() handler and I/O path for avoiding ABBA deadlock:
- * - bd_mutex is held before calling block driver's open/close
- *   handler
- * - reading partition table may submit I/O to the block device
- */
-int blkdev_reread_part(struct block_device *bdev)
-{
-	int res;
-
 	mutex_lock(&bdev->bd_mutex);
-	res = __blkdev_reread_part(bdev);
+	ret = bdev_disk_changed(bdev, false);
 	mutex_unlock(&bdev->bd_mutex);
 
-	return res;
+	return ret;
 }
-EXPORT_SYMBOL(blkdev_reread_part);
 
 static int blk_ioctl_discard(struct block_device *bdev, fmode_t mode,
 		unsigned long arg, unsigned long flags)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index f6f77eaa7217..64b16abee280 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -630,7 +630,9 @@  static void loop_reread_partitions(struct loop_device *lo,
 {
 	int rc;
 
-	rc = blkdev_reread_part(bdev);
+	mutex_lock(&bdev->bd_mutex);
+	rc = bdev_disk_changed(bdev, false);
+	mutex_unlock(&bdev->bd_mutex);
 	if (rc)
 		pr_warn("%s: partition scan of loop%d (%s) failed (rc=%d)\n",
 			__func__, lo->lo_number, lo->lo_file_name, rc);
@@ -1154,10 +1156,11 @@  static int __loop_clr_fd(struct loop_device *lo, bool release)
 		 * must be at least one and it can only become zero when the
 		 * current holder is released.
 		 */
-		if (release)
-			err = __blkdev_reread_part(bdev);
-		else
-			err = blkdev_reread_part(bdev);
+		if (!release)
+			mutex_lock(&bdev->bd_mutex);
+		err = bdev_disk_changed(bdev, false);
+		if (!release)
+			mutex_unlock(&bdev->bd_mutex);
 		if (err)
 			pr_warn("%s: partition scan of loop%d failed (rc=%d)\n",
 				__func__, lo_number, err);
diff --git a/drivers/s390/block/dasd_genhd.c b/drivers/s390/block/dasd_genhd.c
index 5542d9eadfe0..7d079154f849 100644
--- a/drivers/s390/block/dasd_genhd.c
+++ b/drivers/s390/block/dasd_genhd.c
@@ -116,7 +116,9 @@  int dasd_scan_partitions(struct dasd_block *block)
 		return -ENODEV;
 	}
 
-	rc = blkdev_reread_part(bdev);
+	mutex_lock(&bdev->bd_mutex);
+	rc = bdev_disk_changed(bdev, false);
+	mutex_unlock(&bdev->bd_mutex);
 	if (rc)
 		DBF_DEV_EVENT(DBF_ERR, block->base,
 				"scan partitions error, rc %d", rc);
diff --git a/fs/block_dev.c b/fs/block_dev.c
index ae16466a67f7..9558a2f064b1 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1513,6 +1513,8 @@  int bdev_disk_changed(struct block_device *bdev, bool invalidate)
 	struct gendisk *disk = bdev->bd_disk;
 	int ret;
 
+	lockdep_assert_held(&bdev->bd_mutex);
+
 rescan:
 	ret = blk_drop_partitions(disk, bdev);
 	if (ret)
@@ -1540,6 +1542,11 @@  int bdev_disk_changed(struct block_device *bdev, bool invalidate)
 
 	return ret;
 }
+/*
+ * Only exported for for loop and dasd for historic reasons.  Don't use in new
+ * code!
+ */
+EXPORT_SYMBOL_GPL(bdev_disk_changed);
 
 /*
  * bd_mutex locking:
diff --git a/include/linux/fs.h b/include/linux/fs.h
index d233dd661df7..ae6c5c37f3ae 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2632,8 +2632,6 @@  extern void bd_finish_claiming(struct block_device *bdev,
 extern void bd_abort_claiming(struct block_device *bdev,
 			      struct block_device *whole, void *holder);
 extern void blkdev_put(struct block_device *bdev, fmode_t mode);
-extern int __blkdev_reread_part(struct block_device *bdev);
-extern int blkdev_reread_part(struct block_device *bdev);
 
 #ifdef CONFIG_SYSFS
 extern int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk);