diff mbox series

[12/20] block: simplify the block device claiming interface

Message ID 20201118084800.2339180-13-hch@lst.de (mailing list archive)
State Superseded
Headers show
Series [01/20] blk-cgroup: fix a hd_struct leak in blkcg_fill_root_iostats | expand

Commit Message

Christoph Hellwig Nov. 18, 2020, 8:47 a.m. UTC 
Stop passing the whole device as a separate argument given that it
can be trivially deducted.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/block/loop.c   | 12 +++-----
 fs/block_dev.c         | 69 +++++++++++++++++++-----------------------
 include/linux/blkdev.h |  6 ++--
 3 files changed, 38 insertions(+), 49 deletions(-)

Comments

Jan Kara Nov. 19, 2020, 10:07 a.m. UTC | #1 
On Wed 18-11-20 09:47:52, Christoph Hellwig wrote:
> Stop passing the whole device as a separate argument given that it
> can be trivially deducted.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

The patch looks good to me. You can add:

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

								Honza

> ---
>  drivers/block/loop.c   | 12 +++-----
>  fs/block_dev.c         | 69 +++++++++++++++++++-----------------------
>  include/linux/blkdev.h |  6 ++--
>  3 files changed, 38 insertions(+), 49 deletions(-)
> 
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index b42c728620c9e4..599e94a7e69259 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -1071,7 +1071,6 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
>  	struct file	*file;
>  	struct inode	*inode;
>  	struct address_space *mapping;
> -	struct block_device *claimed_bdev = NULL;
>  	int		error;
>  	loff_t		size;
>  	bool		partscan;
> @@ -1090,8 +1089,7 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
>  	 * here to avoid changing device under exclusive owner.
>  	 */
>  	if (!(mode & FMODE_EXCL)) {
> -		claimed_bdev = bdev->bd_contains;
> -		error = bd_prepare_to_claim(bdev, claimed_bdev, loop_configure);
> +		error = bd_prepare_to_claim(bdev, loop_configure);
>  		if (error)
>  			goto out_putf;
>  	}
> @@ -1178,15 +1176,15 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
>  	mutex_unlock(&loop_ctl_mutex);
>  	if (partscan)
>  		loop_reread_partitions(lo, bdev);
> -	if (claimed_bdev)
> -		bd_abort_claiming(bdev, claimed_bdev, loop_configure);
> +	if (!(mode & FMODE_EXCL))
> +		bd_abort_claiming(bdev, loop_configure);
>  	return 0;
>  
>  out_unlock:
>  	mutex_unlock(&loop_ctl_mutex);
>  out_bdev:
> -	if (claimed_bdev)
> -		bd_abort_claiming(bdev, claimed_bdev, loop_configure);
> +	if (!(mode & FMODE_EXCL))
> +		bd_abort_claiming(bdev, loop_configure);
>  out_putf:
>  	fput(file);
>  out:
> diff --git a/fs/block_dev.c b/fs/block_dev.c
> index e94633dc6ad93b..dd52dbd266cde7 100644
> --- a/fs/block_dev.c
> +++ b/fs/block_dev.c
> @@ -110,24 +110,20 @@ EXPORT_SYMBOL(invalidate_bdev);
>  int truncate_bdev_range(struct block_device *bdev, fmode_t mode,
>  			loff_t lstart, loff_t lend)
>  {
> -	struct block_device *claimed_bdev = NULL;
> -	int err;
> -
>  	/*
>  	 * If we don't hold exclusive handle for the device, upgrade to it
>  	 * while we discard the buffer cache to avoid discarding buffers
>  	 * under live filesystem.
>  	 */
>  	if (!(mode & FMODE_EXCL)) {
> -		claimed_bdev = bdev->bd_contains;
> -		err = bd_prepare_to_claim(bdev, claimed_bdev,
> -					  truncate_bdev_range);
> +		int err = bd_prepare_to_claim(bdev, truncate_bdev_range);
>  		if (err)
>  			return err;
>  	}
> +
>  	truncate_inode_pages_range(bdev->bd_inode->i_mapping, lstart, lend);
> -	if (claimed_bdev)
> -		bd_abort_claiming(bdev, claimed_bdev, truncate_bdev_range);
> +	if (!(mode & FMODE_EXCL))
> +		bd_abort_claiming(bdev, truncate_bdev_range);
>  	return 0;
>  }
>  EXPORT_SYMBOL(truncate_bdev_range);
> @@ -1047,7 +1043,6 @@ static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
>  /**
>   * bd_prepare_to_claim - claim a block device
>   * @bdev: block device of interest
> - * @whole: the whole device containing @bdev, may equal @bdev
>   * @holder: holder trying to claim @bdev
>   *
>   * Claim @bdev.  This function fails if @bdev is already claimed by another
> @@ -1057,9 +1052,10 @@ static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
>   * RETURNS:
>   * 0 if @bdev can be claimed, -EBUSY otherwise.
>   */
> -int bd_prepare_to_claim(struct block_device *bdev, struct block_device *whole,
> -		void *holder)
> +int bd_prepare_to_claim(struct block_device *bdev, void *holder)
>  {
> +	struct block_device *whole = bdev->bd_contains;
> +
>  retry:
>  	spin_lock(&bdev_lock);
>  	/* if someone else claimed, fail */
> @@ -1099,15 +1095,15 @@ static void bd_clear_claiming(struct block_device *whole, void *holder)
>  /**
>   * bd_finish_claiming - finish claiming of a block device
>   * @bdev: block device of interest
> - * @whole: whole block device
>   * @holder: holder that has claimed @bdev
>   *
>   * Finish exclusive open of a block device. Mark the device as exlusively
>   * open by the holder and wake up all waiters for exclusive open to finish.
>   */
> -static void bd_finish_claiming(struct block_device *bdev,
> -		struct block_device *whole, void *holder)
> +static void bd_finish_claiming(struct block_device *bdev, void *holder)
>  {
> +	struct block_device *whole = bdev->bd_contains;
> +
>  	spin_lock(&bdev_lock);
>  	BUG_ON(!bd_may_claim(bdev, whole, holder));
>  	/*
> @@ -1132,11 +1128,10 @@ static void bd_finish_claiming(struct block_device *bdev,
>   * also used when exclusive open is not actually desired and we just needed
>   * to block other exclusive openers for a while.
>   */
> -void bd_abort_claiming(struct block_device *bdev, struct block_device *whole,
> -		       void *holder)
> +void bd_abort_claiming(struct block_device *bdev, void *holder)
>  {
>  	spin_lock(&bdev_lock);
> -	bd_clear_claiming(whole, holder);
> +	bd_clear_claiming(bdev->bd_contains, holder);
>  	spin_unlock(&bdev_lock);
>  }
>  EXPORT_SYMBOL(bd_abort_claiming);
> @@ -1434,7 +1429,7 @@ static void put_disk_and_module(struct gendisk *disk)
>  static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
>  		int for_part)
>  {
> -	struct block_device *whole = NULL, *claiming = NULL;
> +	struct block_device *whole = NULL;
>  	struct gendisk *disk = bdev->bd_disk;
>  	int ret;
>  	bool first_open = false, unblock_events = true, need_restart;
> @@ -1462,11 +1457,7 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
>  
>  	if (!for_part && (mode & FMODE_EXCL)) {
>  		WARN_ON_ONCE(!holder);
> -		if (whole)
> -			claiming = whole;
> -		else
> -			claiming = bdev;
> -		ret = bd_prepare_to_claim(bdev, claiming, holder);
> +		ret = bd_prepare_to_claim(bdev, holder);
>  		if (ret)
>  			goto out_put_whole;
>  	}
> @@ -1543,21 +1534,23 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
>  		}
>  	}
>  	bdev->bd_openers++;
> -	if (for_part)
> +	if (for_part) {
>  		bdev->bd_part_count++;
> -	if (claiming)
> -		bd_finish_claiming(bdev, claiming, holder);
> +	} else if (mode & FMODE_EXCL) {
> +		bd_finish_claiming(bdev, holder);
>  
> -	/*
> -	 * Block event polling for write claims if requested.  Any write holder
> -	 * makes the write_holder state stick until all are released.  This is
> -	 * good enough and tracking individual writeable reference is too
> -	 * fragile given the way @mode is used in blkdev_get/put().
> -	 */
> -	if (claiming && (mode & FMODE_WRITE) && !bdev->bd_write_holder &&
> -	    (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) {
> -		bdev->bd_write_holder = true;
> -		unblock_events = false;
> +		/*
> +		 * Block event polling for write claims if requested.  Any write
> +		 * holder makes the write_holder state stick until all are
> +		 * released.  This is good enough and tracking individual
> +		 * writeable reference is too fragile given the way @mode is
> +		 * used in blkdev_get/put().
> +		 */
> +		if ((mode & FMODE_WRITE) && !bdev->bd_write_holder &&
> +		    (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) {
> +			bdev->bd_write_holder = true;
> +			unblock_events = false;
> +		}
>  	}
>  	mutex_unlock(&bdev->bd_mutex);
>  
> @@ -1578,8 +1571,8 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
>  		__blkdev_put(bdev->bd_contains, mode, 1);
>  	bdev->bd_contains = NULL;
>   out_unlock_bdev:
> -	if (claiming)
> -		bd_abort_claiming(bdev, claiming, holder);
> +	if (!for_part && (mode & FMODE_EXCL))
> +		bd_abort_claiming(bdev, holder);
>  	mutex_unlock(&bdev->bd_mutex);
>  	disk_unblock_events(disk);
>   out_put_whole:
> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
> index 044d9dd159d882..696b2f9c5529d8 100644
> --- a/include/linux/blkdev.h
> +++ b/include/linux/blkdev.h
> @@ -1988,10 +1988,8 @@ void blkdev_show(struct seq_file *seqf, off_t offset);
>  struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
>  		void *holder);
>  struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder);
> -int bd_prepare_to_claim(struct block_device *bdev, struct block_device *whole,
> -		void *holder);
> -void bd_abort_claiming(struct block_device *bdev, struct block_device *whole,
> -		void *holder);
> +int bd_prepare_to_claim(struct block_device *bdev, void *holder);
> +void bd_abort_claiming(struct block_device *bdev, void *holder);
>  void blkdev_put(struct block_device *bdev, fmode_t mode);
>  
>  struct block_device *bdev_alloc(struct gendisk *disk, u8 partno);
> -- 
> 2.29.2
>
diff mbox series

Patch

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index b42c728620c9e4..599e94a7e69259 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1071,7 +1071,6 @@  static int loop_configure(struct loop_device *lo, fmode_t mode,
 	struct file	*file;
 	struct inode	*inode;
 	struct address_space *mapping;
-	struct block_device *claimed_bdev = NULL;
 	int		error;
 	loff_t		size;
 	bool		partscan;
@@ -1090,8 +1089,7 @@  static int loop_configure(struct loop_device *lo, fmode_t mode,
 	 * here to avoid changing device under exclusive owner.
 	 */
 	if (!(mode & FMODE_EXCL)) {
-		claimed_bdev = bdev->bd_contains;
-		error = bd_prepare_to_claim(bdev, claimed_bdev, loop_configure);
+		error = bd_prepare_to_claim(bdev, loop_configure);
 		if (error)
 			goto out_putf;
 	}
@@ -1178,15 +1176,15 @@  static int loop_configure(struct loop_device *lo, fmode_t mode,
 	mutex_unlock(&loop_ctl_mutex);
 	if (partscan)
 		loop_reread_partitions(lo, bdev);
-	if (claimed_bdev)
-		bd_abort_claiming(bdev, claimed_bdev, loop_configure);
+	if (!(mode & FMODE_EXCL))
+		bd_abort_claiming(bdev, loop_configure);
 	return 0;
 
 out_unlock:
 	mutex_unlock(&loop_ctl_mutex);
 out_bdev:
-	if (claimed_bdev)
-		bd_abort_claiming(bdev, claimed_bdev, loop_configure);
+	if (!(mode & FMODE_EXCL))
+		bd_abort_claiming(bdev, loop_configure);
 out_putf:
 	fput(file);
 out:
diff --git a/fs/block_dev.c b/fs/block_dev.c
index e94633dc6ad93b..dd52dbd266cde7 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -110,24 +110,20 @@  EXPORT_SYMBOL(invalidate_bdev);
 int truncate_bdev_range(struct block_device *bdev, fmode_t mode,
 			loff_t lstart, loff_t lend)
 {
-	struct block_device *claimed_bdev = NULL;
-	int err;
-
 	/*
 	 * If we don't hold exclusive handle for the device, upgrade to it
 	 * while we discard the buffer cache to avoid discarding buffers
 	 * under live filesystem.
 	 */
 	if (!(mode & FMODE_EXCL)) {
-		claimed_bdev = bdev->bd_contains;
-		err = bd_prepare_to_claim(bdev, claimed_bdev,
-					  truncate_bdev_range);
+		int err = bd_prepare_to_claim(bdev, truncate_bdev_range);
 		if (err)
 			return err;
 	}
+
 	truncate_inode_pages_range(bdev->bd_inode->i_mapping, lstart, lend);
-	if (claimed_bdev)
-		bd_abort_claiming(bdev, claimed_bdev, truncate_bdev_range);
+	if (!(mode & FMODE_EXCL))
+		bd_abort_claiming(bdev, truncate_bdev_range);
 	return 0;
 }
 EXPORT_SYMBOL(truncate_bdev_range);
@@ -1047,7 +1043,6 @@  static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
 /**
  * bd_prepare_to_claim - claim a block device
  * @bdev: block device of interest
- * @whole: the whole device containing @bdev, may equal @bdev
  * @holder: holder trying to claim @bdev
  *
  * Claim @bdev.  This function fails if @bdev is already claimed by another
@@ -1057,9 +1052,10 @@  static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
  * RETURNS:
  * 0 if @bdev can be claimed, -EBUSY otherwise.
  */
-int bd_prepare_to_claim(struct block_device *bdev, struct block_device *whole,
-		void *holder)
+int bd_prepare_to_claim(struct block_device *bdev, void *holder)
 {
+	struct block_device *whole = bdev->bd_contains;
+
 retry:
 	spin_lock(&bdev_lock);
 	/* if someone else claimed, fail */
@@ -1099,15 +1095,15 @@  static void bd_clear_claiming(struct block_device *whole, void *holder)
 /**
  * bd_finish_claiming - finish claiming of a block device
  * @bdev: block device of interest
- * @whole: whole block device
  * @holder: holder that has claimed @bdev
  *
  * Finish exclusive open of a block device. Mark the device as exlusively
  * open by the holder and wake up all waiters for exclusive open to finish.
  */
-static void bd_finish_claiming(struct block_device *bdev,
-		struct block_device *whole, void *holder)
+static void bd_finish_claiming(struct block_device *bdev, void *holder)
 {
+	struct block_device *whole = bdev->bd_contains;
+
 	spin_lock(&bdev_lock);
 	BUG_ON(!bd_may_claim(bdev, whole, holder));
 	/*
@@ -1132,11 +1128,10 @@  static void bd_finish_claiming(struct block_device *bdev,
  * also used when exclusive open is not actually desired and we just needed
  * to block other exclusive openers for a while.
  */
-void bd_abort_claiming(struct block_device *bdev, struct block_device *whole,
-		       void *holder)
+void bd_abort_claiming(struct block_device *bdev, void *holder)
 {
 	spin_lock(&bdev_lock);
-	bd_clear_claiming(whole, holder);
+	bd_clear_claiming(bdev->bd_contains, holder);
 	spin_unlock(&bdev_lock);
 }
 EXPORT_SYMBOL(bd_abort_claiming);
@@ -1434,7 +1429,7 @@  static void put_disk_and_module(struct gendisk *disk)
 static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
 		int for_part)
 {
-	struct block_device *whole = NULL, *claiming = NULL;
+	struct block_device *whole = NULL;
 	struct gendisk *disk = bdev->bd_disk;
 	int ret;
 	bool first_open = false, unblock_events = true, need_restart;
@@ -1462,11 +1457,7 @@  static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
 
 	if (!for_part && (mode & FMODE_EXCL)) {
 		WARN_ON_ONCE(!holder);
-		if (whole)
-			claiming = whole;
-		else
-			claiming = bdev;
-		ret = bd_prepare_to_claim(bdev, claiming, holder);
+		ret = bd_prepare_to_claim(bdev, holder);
 		if (ret)
 			goto out_put_whole;
 	}
@@ -1543,21 +1534,23 @@  static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
 		}
 	}
 	bdev->bd_openers++;
-	if (for_part)
+	if (for_part) {
 		bdev->bd_part_count++;
-	if (claiming)
-		bd_finish_claiming(bdev, claiming, holder);
+	} else if (mode & FMODE_EXCL) {
+		bd_finish_claiming(bdev, holder);
 
-	/*
-	 * Block event polling for write claims if requested.  Any write holder
-	 * makes the write_holder state stick until all are released.  This is
-	 * good enough and tracking individual writeable reference is too
-	 * fragile given the way @mode is used in blkdev_get/put().
-	 */
-	if (claiming && (mode & FMODE_WRITE) && !bdev->bd_write_holder &&
-	    (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) {
-		bdev->bd_write_holder = true;
-		unblock_events = false;
+		/*
+		 * Block event polling for write claims if requested.  Any write
+		 * holder makes the write_holder state stick until all are
+		 * released.  This is good enough and tracking individual
+		 * writeable reference is too fragile given the way @mode is
+		 * used in blkdev_get/put().
+		 */
+		if ((mode & FMODE_WRITE) && !bdev->bd_write_holder &&
+		    (disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE)) {
+			bdev->bd_write_holder = true;
+			unblock_events = false;
+		}
 	}
 	mutex_unlock(&bdev->bd_mutex);
 
@@ -1578,8 +1571,8 @@  static int __blkdev_get(struct block_device *bdev, fmode_t mode, void *holder,
 		__blkdev_put(bdev->bd_contains, mode, 1);
 	bdev->bd_contains = NULL;
  out_unlock_bdev:
-	if (claiming)
-		bd_abort_claiming(bdev, claiming, holder);
+	if (!for_part && (mode & FMODE_EXCL))
+		bd_abort_claiming(bdev, holder);
 	mutex_unlock(&bdev->bd_mutex);
 	disk_unblock_events(disk);
  out_put_whole:
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 044d9dd159d882..696b2f9c5529d8 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1988,10 +1988,8 @@  void blkdev_show(struct seq_file *seqf, off_t offset);
 struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
 		void *holder);
 struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder);
-int bd_prepare_to_claim(struct block_device *bdev, struct block_device *whole,
-		void *holder);
-void bd_abort_claiming(struct block_device *bdev, struct block_device *whole,
-		void *holder);
+int bd_prepare_to_claim(struct block_device *bdev, void *holder);
+void bd_abort_claiming(struct block_device *bdev, void *holder);
 void blkdev_put(struct block_device *bdev, fmode_t mode);
 
 struct block_device *bdev_alloc(struct gendisk *disk, u8 partno);