[PATCH] lockdep: annotate blkdev nesting
Teach special (recursive) locking code to the lock validator. Effects on non-lockdep kernels: - the introduction of the following function variants: extern struct block_device *open_partition_by_devnum(dev_t, unsigned); extern int blkdev_put_partition(struct block_device *); static int blkdev_get_whole(struct block_device *bdev, mode_t mode, unsigned flags); which on non-lockdep are the same as open_by_devnum(), blkdev_put() and blkdev_get(). - a subclass parameter to do_open(). [unused on non-lockdep] - a subclass parameter to __blkdev_put(), which is a new internal function for the main blkdev_put*() functions. [parameter unused on non-lockdep kernels, except for two sanity check WARN_ON()s] these functions carry no semantical difference - they only express object dependencies towards the lockdep subsystem. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Cc: Neil Brown <neilb@cse.unsw.edu.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Ingo Molnar
Linus Torvalds
parent
2b2d5493e1
commit
663d440eaa
3 changed files with 107 additions and 18 deletions
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@ -1404,7 +1404,7 @@ static int lock_rdev(mdk_rdev_t *rdev, dev_t dev)
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struct block_device *bdev;
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char b[BDEVNAME_SIZE];
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bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE);
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bdev = open_partition_by_devnum(dev, FMODE_READ|FMODE_WRITE);
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if (IS_ERR(bdev)) {
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printk(KERN_ERR "md: could not open %s.\n",
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__bdevname(dev, b));
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@ -1414,7 +1414,7 @@ static int lock_rdev(mdk_rdev_t *rdev, dev_t dev)
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if (err) {
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printk(KERN_ERR "md: could not bd_claim %s.\n",
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bdevname(bdev, b));
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blkdev_put(bdev);
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blkdev_put_partition(bdev);
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return err;
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}
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rdev->bdev = bdev;
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@ -1428,7 +1428,7 @@ static void unlock_rdev(mdk_rdev_t *rdev)
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if (!bdev)
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MD_BUG();
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bd_release(bdev);
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blkdev_put(bdev);
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blkdev_put_partition(bdev);
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}
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void md_autodetect_dev(dev_t dev);
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102
fs/block_dev.c
102
fs/block_dev.c
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@ -739,7 +739,7 @@ static int bd_claim_by_kobject(struct block_device *bdev, void *holder,
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if (!bo)
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return -ENOMEM;
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mutex_lock(&bdev->bd_mutex);
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mutex_lock_nested(&bdev->bd_mutex, BD_MUTEX_PARTITION);
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res = bd_claim(bdev, holder);
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if (res || !add_bd_holder(bdev, bo))
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free_bd_holder(bo);
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@ -764,7 +764,7 @@ static void bd_release_from_kobject(struct block_device *bdev,
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if (!kobj)
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return;
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mutex_lock(&bdev->bd_mutex);
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mutex_lock_nested(&bdev->bd_mutex, BD_MUTEX_PARTITION);
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bd_release(bdev);
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if ((bo = del_bd_holder(bdev, kobj)))
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free_bd_holder(bo);
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@ -822,6 +822,22 @@ struct block_device *open_by_devnum(dev_t dev, unsigned mode)
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EXPORT_SYMBOL(open_by_devnum);
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static int
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blkdev_get_partition(struct block_device *bdev, mode_t mode, unsigned flags);
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struct block_device *open_partition_by_devnum(dev_t dev, unsigned mode)
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{
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struct block_device *bdev = bdget(dev);
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int err = -ENOMEM;
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int flags = mode & FMODE_WRITE ? O_RDWR : O_RDONLY;
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if (bdev)
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err = blkdev_get_partition(bdev, mode, flags);
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return err ? ERR_PTR(err) : bdev;
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}
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EXPORT_SYMBOL(open_partition_by_devnum);
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/*
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* This routine checks whether a removable media has been changed,
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* and invalidates all buffer-cache-entries in that case. This
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@ -868,7 +884,11 @@ void bd_set_size(struct block_device *bdev, loff_t size)
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}
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EXPORT_SYMBOL(bd_set_size);
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static int do_open(struct block_device *bdev, struct file *file)
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static int
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blkdev_get_whole(struct block_device *bdev, mode_t mode, unsigned flags);
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static int
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do_open(struct block_device *bdev, struct file *file, unsigned int subclass)
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{
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struct module *owner = NULL;
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struct gendisk *disk;
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@ -885,7 +905,8 @@ static int do_open(struct block_device *bdev, struct file *file)
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}
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owner = disk->fops->owner;
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mutex_lock(&bdev->bd_mutex);
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mutex_lock_nested(&bdev->bd_mutex, subclass);
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if (!bdev->bd_openers) {
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bdev->bd_disk = disk;
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bdev->bd_contains = bdev;
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@ -912,11 +933,11 @@ static int do_open(struct block_device *bdev, struct file *file)
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ret = -ENOMEM;
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if (!whole)
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goto out_first;
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ret = blkdev_get(whole, file->f_mode, file->f_flags);
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ret = blkdev_get_whole(whole, file->f_mode, file->f_flags);
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if (ret)
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goto out_first;
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bdev->bd_contains = whole;
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mutex_lock(&whole->bd_mutex);
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mutex_lock_nested(&whole->bd_mutex, BD_MUTEX_WHOLE);
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whole->bd_part_count++;
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p = disk->part[part - 1];
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bdev->bd_inode->i_data.backing_dev_info =
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@ -944,7 +965,8 @@ static int do_open(struct block_device *bdev, struct file *file)
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if (bdev->bd_invalidated)
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rescan_partitions(bdev->bd_disk, bdev);
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} else {
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mutex_lock(&bdev->bd_contains->bd_mutex);
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mutex_lock_nested(&bdev->bd_contains->bd_mutex,
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BD_MUTEX_PARTITION);
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bdev->bd_contains->bd_part_count++;
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mutex_unlock(&bdev->bd_contains->bd_mutex);
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}
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@ -985,11 +1007,49 @@ int blkdev_get(struct block_device *bdev, mode_t mode, unsigned flags)
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fake_file.f_dentry = &fake_dentry;
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fake_dentry.d_inode = bdev->bd_inode;
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return do_open(bdev, &fake_file);
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return do_open(bdev, &fake_file, BD_MUTEX_NORMAL);
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}
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EXPORT_SYMBOL(blkdev_get);
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static int
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blkdev_get_whole(struct block_device *bdev, mode_t mode, unsigned flags)
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{
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/*
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* This crockload is due to bad choice of ->open() type.
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* It will go away.
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* For now, block device ->open() routine must _not_
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* examine anything in 'inode' argument except ->i_rdev.
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*/
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struct file fake_file = {};
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struct dentry fake_dentry = {};
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fake_file.f_mode = mode;
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fake_file.f_flags = flags;
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fake_file.f_dentry = &fake_dentry;
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fake_dentry.d_inode = bdev->bd_inode;
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return do_open(bdev, &fake_file, BD_MUTEX_WHOLE);
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}
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static int
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blkdev_get_partition(struct block_device *bdev, mode_t mode, unsigned flags)
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{
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/*
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* This crockload is due to bad choice of ->open() type.
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* It will go away.
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* For now, block device ->open() routine must _not_
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* examine anything in 'inode' argument except ->i_rdev.
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*/
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struct file fake_file = {};
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struct dentry fake_dentry = {};
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fake_file.f_mode = mode;
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fake_file.f_flags = flags;
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fake_file.f_dentry = &fake_dentry;
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fake_dentry.d_inode = bdev->bd_inode;
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return do_open(bdev, &fake_file, BD_MUTEX_PARTITION);
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}
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static int blkdev_open(struct inode * inode, struct file * filp)
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{
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struct block_device *bdev;
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@ -1005,7 +1065,7 @@ static int blkdev_open(struct inode * inode, struct file * filp)
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bdev = bd_acquire(inode);
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res = do_open(bdev, filp);
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res = do_open(bdev, filp, BD_MUTEX_NORMAL);
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if (res)
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return res;
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@ -1019,13 +1079,13 @@ static int blkdev_open(struct inode * inode, struct file * filp)
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return res;
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}
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int blkdev_put(struct block_device *bdev)
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static int __blkdev_put(struct block_device *bdev, unsigned int subclass)
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{
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int ret = 0;
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struct inode *bd_inode = bdev->bd_inode;
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struct gendisk *disk = bdev->bd_disk;
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mutex_lock(&bdev->bd_mutex);
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mutex_lock_nested(&bdev->bd_mutex, subclass);
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lock_kernel();
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if (!--bdev->bd_openers) {
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sync_blockdev(bdev);
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@ -1035,7 +1095,8 @@ int blkdev_put(struct block_device *bdev)
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if (disk->fops->release)
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ret = disk->fops->release(bd_inode, NULL);
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} else {
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mutex_lock(&bdev->bd_contains->bd_mutex);
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mutex_lock_nested(&bdev->bd_contains->bd_mutex,
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subclass + 1);
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bdev->bd_contains->bd_part_count--;
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mutex_unlock(&bdev->bd_contains->bd_mutex);
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}
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@ -1051,9 +1112,8 @@ int blkdev_put(struct block_device *bdev)
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}
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bdev->bd_disk = NULL;
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bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;
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if (bdev != bdev->bd_contains) {
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blkdev_put(bdev->bd_contains);
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}
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if (bdev != bdev->bd_contains)
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__blkdev_put(bdev->bd_contains, subclass + 1);
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bdev->bd_contains = NULL;
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}
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unlock_kernel();
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@ -1062,8 +1122,20 @@ int blkdev_put(struct block_device *bdev)
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return ret;
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}
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int blkdev_put(struct block_device *bdev)
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{
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return __blkdev_put(bdev, BD_MUTEX_NORMAL);
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}
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EXPORT_SYMBOL(blkdev_put);
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int blkdev_put_partition(struct block_device *bdev)
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{
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return __blkdev_put(bdev, BD_MUTEX_PARTITION);
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}
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EXPORT_SYMBOL(blkdev_put_partition);
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static int blkdev_close(struct inode * inode, struct file * filp)
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{
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struct block_device *bdev = I_BDEV(filp->f_mapping->host);
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@ -435,6 +435,21 @@ struct block_device {
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unsigned long bd_private;
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};
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/*
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* bdev->bd_mutex nesting subclasses for the lock validator:
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*
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* 0: normal
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* 1: 'whole'
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* 2: 'partition'
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*/
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enum bdev_bd_mutex_lock_class
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{
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BD_MUTEX_NORMAL,
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BD_MUTEX_WHOLE,
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BD_MUTEX_PARTITION
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};
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/*
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* Radix-tree tags, for tagging dirty and writeback pages within the pagecache
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* radix trees
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@ -1425,6 +1440,7 @@ extern void bd_set_size(struct block_device *, loff_t size);
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extern void bd_forget(struct inode *inode);
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extern void bdput(struct block_device *);
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extern struct block_device *open_by_devnum(dev_t, unsigned);
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extern struct block_device *open_partition_by_devnum(dev_t, unsigned);
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extern const struct file_operations def_blk_fops;
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extern const struct address_space_operations def_blk_aops;
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extern const struct file_operations def_chr_fops;
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@ -1435,6 +1451,7 @@ extern int blkdev_ioctl(struct inode *, struct file *, unsigned, unsigned long);
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extern long compat_blkdev_ioctl(struct file *, unsigned, unsigned long);
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extern int blkdev_get(struct block_device *, mode_t, unsigned);
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extern int blkdev_put(struct block_device *);
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extern int blkdev_put_partition(struct block_device *);
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extern int bd_claim(struct block_device *, void *);
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extern void bd_release(struct block_device *);
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#ifdef CONFIG_SYSFS
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