block: simplify the block device claiming interface

Stop passing the whole device as a separate argument given that it
can be trivially deducted and cleanup the !holder debug check.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index c0df88b..d643c67 100644 (file)
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1069,7 +1069,6 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
        struct file     *file;
        struct inode    *inode;
        struct address_space *mapping;
        struct file     *file;
        struct inode    *inode;
        struct address_space *mapping;

-       struct block_device *claimed_bdev = NULL;

        int             error;
        loff_t          size;
        bool            partscan;
        int             error;
        loff_t          size;
        bool            partscan;


@@ -1088,8 +1087,7 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
         * here to avoid changing device under exclusive owner.
         */
        if (!(mode & FMODE_EXCL)) {
         * here to avoid changing device under exclusive owner.
         */
        if (!(mode & FMODE_EXCL)) {

-               claimed_bdev = bdev_whole(bdev);
-               error = bd_prepare_to_claim(bdev, claimed_bdev, loop_configure);
+               error = bd_prepare_to_claim(bdev, loop_configure);

                if (error)
                        goto out_putf;
        }
                if (error)
                        goto out_putf;
        }


@@ -1176,15 +1174,15 @@ static int loop_configure(struct loop_device *lo, fmode_t mode,
        mutex_unlock(&loop_ctl_mutex);
        if (partscan)
                loop_reread_partitions(lo, bdev);
        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:
        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:
 out_putf:
        fput(file);
 out:

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 94baee3..0569f5e 100644 (file)
--- 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)
 {
 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)) {
        /*
         * 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_whole(bdev);
-               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;
        }
                if (err)
                        return err;
        }

+

        truncate_inode_pages_range(bdev->bd_inode->i_mapping, lstart, lend);
        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);
        return 0;
 }
 EXPORT_SYMBOL(truncate_bdev_range);


@@ -978,7 +974,6 @@ 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
 /**
  * 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
  * @holder: holder trying to claim @bdev
  *
  * Claim @bdev.  This function fails if @bdev is already claimed by another


@@ -988,9 +983,12 @@ static bool bd_may_claim(struct block_device *bdev, struct block_device *whole,
  * RETURNS:
  * 0 if @bdev can be claimed, -EBUSY otherwise.
  */
  * 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_whole(bdev);
+
+       if (WARN_ON_ONCE(!holder))
+               return -EINVAL;

 retry:
        spin_lock(&bdev_lock);
        /* if someone else claimed, fail */
 retry:
        spin_lock(&bdev_lock);
        /* if someone else claimed, fail */


@@ -1030,15 +1028,15 @@ 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
 /**
  * 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.
  */
  * @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_whole(bdev);
+

        spin_lock(&bdev_lock);
        BUG_ON(!bd_may_claim(bdev, whole, holder));
        /*
        spin_lock(&bdev_lock);
        BUG_ON(!bd_may_claim(bdev, whole, holder));
        /*


@@ -1063,11 +1061,10 @@ 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.
  */
  * 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);
 {
        spin_lock(&bdev_lock);

-       bd_clear_claiming(whole, holder);
+       bd_clear_claiming(bdev_whole(bdev), holder);

        spin_unlock(&bdev_lock);
 }
 EXPORT_SYMBOL(bd_abort_claiming);
        spin_unlock(&bdev_lock);
 }
 EXPORT_SYMBOL(bd_abort_claiming);


@@ -1487,7 +1484,6 @@ void blkdev_put_no_open(struct block_device *bdev)
  */
 struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
 {
  */
 struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
 {

-       struct block_device *claiming;

        bool unblock_events = true;
        struct block_device *bdev;
        struct gendisk *disk;
        bool unblock_events = true;
        struct block_device *bdev;
        struct gendisk *disk;


@@ -1510,15 +1506,9 @@ retry:
        disk = bdev->bd_disk;
 
        if (mode & FMODE_EXCL) {
        disk = bdev->bd_disk;
 
        if (mode & FMODE_EXCL) {

-               WARN_ON_ONCE(!holder);
-       
-               ret = -ENOMEM;
-               claiming = bdget_disk(disk, 0);
-               if (!claiming)
-                       goto put_blkdev;
-               ret = bd_prepare_to_claim(bdev, claiming, holder);
+               ret = bd_prepare_to_claim(bdev, holder);

                if (ret)
                if (ret)

-                       goto put_claiming;
+                       goto put_blkdev;

        }
 
        disk_block_events(disk);
        }
 
        disk_block_events(disk);


@@ -1528,7 +1518,7 @@ retry:
        if (ret)
                goto abort_claiming;
        if (mode & FMODE_EXCL) {
        if (ret)
                goto abort_claiming;
        if (mode & FMODE_EXCL) {

-               bd_finish_claiming(bdev, claiming, holder);
+               bd_finish_claiming(bdev, holder);

 
                /*
                 * Block event polling for write claims if requested.  Any write
 
                /*
                 * Block event polling for write claims if requested.  Any write


@@ -1547,18 +1537,13 @@ retry:
 
        if (unblock_events)
                disk_unblock_events(disk);
 
        if (unblock_events)
                disk_unblock_events(disk);

-       if (mode & FMODE_EXCL)
-               bdput(claiming);

        return bdev;
 
 abort_claiming:
        if (mode & FMODE_EXCL)
        return bdev;
 
 abort_claiming:
        if (mode & FMODE_EXCL)

-               bd_abort_claiming(bdev, claiming, holder);
+               bd_abort_claiming(bdev, holder);

        mutex_unlock(&bdev->bd_mutex);
        disk_unblock_events(disk);
        mutex_unlock(&bdev->bd_mutex);
        disk_unblock_events(disk);

-put_claiming:
-       if (mode & FMODE_EXCL)
-               bdput(claiming);

 put_blkdev:
        blkdev_put_no_open(bdev);
        if (ret == -ERESTARTSYS)
 put_blkdev:
        blkdev_put_no_open(bdev);
        if (ret == -ERESTARTSYS)

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 5d48b92..43a25d8 100644 (file)
--- 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);
 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);
 
 /* just for blk-cgroup, don't use elsewhere */
 void blkdev_put(struct block_device *bdev, fmode_t mode);
 
 /* just for blk-cgroup, don't use elsewhere */