Commit 663d440e authored by Ingo Molnar's avatar Ingo Molnar Committed by Linus Torvalds
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[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
......@@ -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);
......
......@@ -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);
......
......@@ -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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