Commit 663d440e authored by Ingo Molnar's avatar Ingo Molnar Committed by Linus Torvalds
Browse files

[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: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 2b2d5493

drivers/md/md.c

+3 −3
Original line number Diff line number Diff line
@@ -1404,7 +1404,7 @@ static int lock_rdev(mdk_rdev_t *rdev, dev_t dev) 
	struct block_device *bdev;

	char b[BDEVNAME_SIZE];



	bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE);

	bdev = open_partition_by_devnum(dev, FMODE_READ|FMODE_WRITE);

	if (IS_ERR(bdev)) {

		printk(KERN_ERR "md: could not open %s.\n",

			__bdevname(dev, b));
@@ -1414,7 +1414,7 @@ static int lock_rdev(mdk_rdev_t *rdev, dev_t dev) 
	if (err) {

		printk(KERN_ERR "md: could not bd_claim %s.\n",

			bdevname(bdev, b));

		blkdev_put(bdev);

		blkdev_put_partition(bdev);

		return err;

	}

	rdev->bdev = bdev;
@@ -1428,7 +1428,7 @@ static void unlock_rdev(mdk_rdev_t *rdev) 
	if (!bdev)

		MD_BUG();

	bd_release(bdev);

	blkdev_put(bdev);

	blkdev_put_partition(bdev);

}



void md_autodetect_dev(dev_t dev);

fs/block_dev.c

+87 −15
Original line number Diff line number Diff line
@@ -739,7 +739,7 @@ static int bd_claim_by_kobject(struct block_device *bdev, void *holder, 
	if (!bo)

		return -ENOMEM;



	mutex_lock(&bdev->bd_mutex);

	mutex_lock_nested(&bdev->bd_mutex, BD_MUTEX_PARTITION);

	res = bd_claim(bdev, holder);

	if (res || !add_bd_holder(bdev, bo))

		free_bd_holder(bo);
@@ -764,7 +764,7 @@ static void bd_release_from_kobject(struct block_device *bdev, 
	if (!kobj)

		return;



	mutex_lock(&bdev->bd_mutex);

	mutex_lock_nested(&bdev->bd_mutex, BD_MUTEX_PARTITION);

	bd_release(bdev);

	if ((bo = del_bd_holder(bdev, kobj)))

		free_bd_holder(bo);
@@ -822,6 +822,22 @@ struct block_device *open_by_devnum(dev_t dev, unsigned mode) 


EXPORT_SYMBOL(open_by_devnum);



static int

blkdev_get_partition(struct block_device *bdev, mode_t mode, unsigned flags);



struct block_device *open_partition_by_devnum(dev_t dev, unsigned mode)

{

	struct block_device *bdev = bdget(dev);

	int err = -ENOMEM;

	int flags = mode & FMODE_WRITE ? O_RDWR : O_RDONLY;

	if (bdev)

		err = blkdev_get_partition(bdev, mode, flags);

	return err ? ERR_PTR(err) : bdev;

}



EXPORT_SYMBOL(open_partition_by_devnum);





/*

 * This routine checks whether a removable media has been changed,

 * and invalidates all buffer-cache-entries in that case. This
@@ -868,7 +884,11 @@ void bd_set_size(struct block_device *bdev, loff_t size) 
}

EXPORT_SYMBOL(bd_set_size);



static int do_open(struct block_device *bdev, struct file *file)

static int

blkdev_get_whole(struct block_device *bdev, mode_t mode, unsigned flags);



static int

do_open(struct block_device *bdev, struct file *file, unsigned int subclass)

{

	struct module *owner = NULL;

	struct gendisk *disk;
@@ -885,7 +905,8 @@ static int do_open(struct block_device *bdev, struct file *file) 
	}

	owner = disk->fops->owner;



	mutex_lock(&bdev->bd_mutex);

	mutex_lock_nested(&bdev->bd_mutex, subclass);



	if (!bdev->bd_openers) {

		bdev->bd_disk = disk;

		bdev->bd_contains = bdev;
@@ -912,11 +933,11 @@ static int do_open(struct block_device *bdev, struct file *file) 
			ret = -ENOMEM;

			if (!whole)

				goto out_first;

			ret = blkdev_get(whole, file->f_mode, file->f_flags);

			ret = blkdev_get_whole(whole, file->f_mode, file->f_flags);

			if (ret)

				goto out_first;

			bdev->bd_contains = whole;

			mutex_lock(&whole->bd_mutex);

			mutex_lock_nested(&whole->bd_mutex, BD_MUTEX_WHOLE);

			whole->bd_part_count++;

			p = disk->part[part - 1];

			bdev->bd_inode->i_data.backing_dev_info =
@@ -944,7 +965,8 @@ static int do_open(struct block_device *bdev, struct file *file) 
			if (bdev->bd_invalidated)

				rescan_partitions(bdev->bd_disk, bdev);

		} else {

			mutex_lock(&bdev->bd_contains->bd_mutex);

			mutex_lock_nested(&bdev->bd_contains->bd_mutex,

					  BD_MUTEX_PARTITION);

			bdev->bd_contains->bd_part_count++;

			mutex_unlock(&bdev->bd_contains->bd_mutex);

		}
@@ -985,11 +1007,49 @@ int blkdev_get(struct block_device *bdev, mode_t mode, unsigned flags) 
	fake_file.f_dentry = &fake_dentry;

	fake_dentry.d_inode = bdev->bd_inode;



	return do_open(bdev, &fake_file);

	return do_open(bdev, &fake_file, BD_MUTEX_NORMAL);

}



EXPORT_SYMBOL(blkdev_get);



static int

blkdev_get_whole(struct block_device *bdev, mode_t mode, unsigned flags)

{

	/*

	 * This crockload is due to bad choice of ->open() type.

	 * It will go away.

	 * For now, block device ->open() routine must _not_

	 * examine anything in 'inode' argument except ->i_rdev.

	 */

	struct file fake_file = {};

	struct dentry fake_dentry = {};

	fake_file.f_mode = mode;

	fake_file.f_flags = flags;

	fake_file.f_dentry = &fake_dentry;

	fake_dentry.d_inode = bdev->bd_inode;



	return do_open(bdev, &fake_file, BD_MUTEX_WHOLE);

}



static int

blkdev_get_partition(struct block_device *bdev, mode_t mode, unsigned flags)

{

	/*

	 * This crockload is due to bad choice of ->open() type.

	 * It will go away.

	 * For now, block device ->open() routine must _not_

	 * examine anything in 'inode' argument except ->i_rdev.

	 */

	struct file fake_file = {};

	struct dentry fake_dentry = {};

	fake_file.f_mode = mode;

	fake_file.f_flags = flags;

	fake_file.f_dentry = &fake_dentry;

	fake_dentry.d_inode = bdev->bd_inode;



	return do_open(bdev, &fake_file, BD_MUTEX_PARTITION);

}



static int blkdev_open(struct inode * inode, struct file * filp)

{

	struct block_device *bdev;
@@ -1005,7 +1065,7 @@ static int blkdev_open(struct inode * inode, struct file * filp) 


	bdev = bd_acquire(inode);



	res = do_open(bdev, filp);

	res = do_open(bdev, filp, BD_MUTEX_NORMAL);

	if (res)

		return res;
@@ -1019,13 +1079,13 @@ static int blkdev_open(struct inode * inode, struct file * filp) 
	return res;

}



int blkdev_put(struct block_device *bdev)

static int __blkdev_put(struct block_device *bdev, unsigned int subclass)

{

	int ret = 0;

	struct inode *bd_inode = bdev->bd_inode;

	struct gendisk *disk = bdev->bd_disk;



	mutex_lock(&bdev->bd_mutex);

	mutex_lock_nested(&bdev->bd_mutex, subclass);

	lock_kernel();

	if (!--bdev->bd_openers) {

		sync_blockdev(bdev);
@@ -1035,7 +1095,8 @@ int blkdev_put(struct block_device *bdev) 
		if (disk->fops->release)

			ret = disk->fops->release(bd_inode, NULL);

	} else {

		mutex_lock(&bdev->bd_contains->bd_mutex);

		mutex_lock_nested(&bdev->bd_contains->bd_mutex,

				  subclass + 1);

		bdev->bd_contains->bd_part_count--;

		mutex_unlock(&bdev->bd_contains->bd_mutex);

	}
@@ -1051,9 +1112,8 @@ int blkdev_put(struct block_device *bdev) 
		}

		bdev->bd_disk = NULL;

		bdev->bd_inode->i_data.backing_dev_info = &default_backing_dev_info;

		if (bdev != bdev->bd_contains) {

			blkdev_put(bdev->bd_contains);

		}

		if (bdev != bdev->bd_contains)

			__blkdev_put(bdev->bd_contains, subclass + 1);

		bdev->bd_contains = NULL;

	}

	unlock_kernel();
@@ -1062,8 +1122,20 @@ int blkdev_put(struct block_device *bdev) 
	return ret;

}



int blkdev_put(struct block_device *bdev)

{

	return __blkdev_put(bdev, BD_MUTEX_NORMAL);

}



EXPORT_SYMBOL(blkdev_put);



int blkdev_put_partition(struct block_device *bdev)

{

	return __blkdev_put(bdev, BD_MUTEX_PARTITION);

}



EXPORT_SYMBOL(blkdev_put_partition);



static int blkdev_close(struct inode * inode, struct file * filp)

{

	struct block_device *bdev = I_BDEV(filp->f_mapping->host);

include/linux/fs.h

+17 −0
Original line number Diff line number Diff line
@@ -435,6 +435,21 @@ struct block_device { 
	unsigned long		bd_private;

};



/*

 * bdev->bd_mutex nesting subclasses for the lock validator:

 *

 * 0: normal

 * 1: 'whole'

 * 2: 'partition'

 */

enum bdev_bd_mutex_lock_class

{

	BD_MUTEX_NORMAL,

	BD_MUTEX_WHOLE,

	BD_MUTEX_PARTITION

};





/*

 * Radix-tree tags, for tagging dirty and writeback pages within the pagecache

 * radix trees
@@ -1425,6 +1440,7 @@ extern void bd_set_size(struct block_device *, loff_t size); 
extern void bd_forget(struct inode *inode);

extern void bdput(struct block_device *);

extern struct block_device *open_by_devnum(dev_t, unsigned);

extern struct block_device *open_partition_by_devnum(dev_t, unsigned);

extern const struct file_operations def_blk_fops;

extern const struct address_space_operations def_blk_aops;

extern const struct file_operations def_chr_fops;
@@ -1435,6 +1451,7 @@ extern int blkdev_ioctl(struct inode *, struct file *, unsigned, unsigned long); 
extern long compat_blkdev_ioctl(struct file *, unsigned, unsigned long);

extern int blkdev_get(struct block_device *, mode_t, unsigned);

extern int blkdev_put(struct block_device *);

extern int blkdev_put_partition(struct block_device *);

extern int bd_claim(struct block_device *, void *);

extern void bd_release(struct block_device *);

#ifdef CONFIG_SYSFS

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