The patch titled
lockdep: fix blkdev_open() warning
has been removed from the -mm tree. Its filename is
lockdep-fix-blkdev_open-warning.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: lockdep: fix blkdev_open() warning
From: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
On Wed, 2006-08-09 at 07:57 +0200, Rolf Eike Beer wrote:
> =============================================
> [ INFO: possible recursive locking detected ]
> ---------------------------------------------
> parted/7929 is trying to acquire lock:
> (&bdev->bd_mutex){--..}, at: [<c105eb8d>] __blkdev_put+0x1e/0x13c
>
> but task is already holding lock:
> (&bdev->bd_mutex){--..}, at: [<c105eec6>] do_open+0x72/0x3a8
>
> other info that might help us debug this:
> 1 lock held by parted/7929:
> #0: (&bdev->bd_mutex){--..}, at: [<c105eec6>] do_open+0x72/0x3a8
> stack backtrace:
> [<c1003aad>] show_trace_log_lvl+0x58/0x15b
> [<c100495f>] show_trace+0xd/0x10
> [<c1004979>] dump_stack+0x17/0x1a
> [<c102dee5>] __lock_acquire+0x753/0x99c
> [<c102e3b0>] lock_acquire+0x4a/0x6a
> [<c1204501>] mutex_lock_nested+0xc8/0x20c
> [<c105eb8d>] __blkdev_put+0x1e/0x13c
> [<c105ecc4>] blkdev_put+0xa/0xc
> [<c105f18a>] do_open+0x336/0x3a8
> [<c105f21b>] blkdev_open+0x1f/0x4c
> [<c1057b40>] __dentry_open+0xc7/0x1aa
> [<c1057c91>] nameidata_to_filp+0x1c/0x2e
> [<c1057cd1>] do_filp_open+0x2e/0x35
> [<c1057dd7>] do_sys_open+0x38/0x68
> [<c1057e33>] sys_open+0x16/0x18
> [<c1002845>] sysenter_past_esp+0x56/0x8d
OK, I'm having a look here; its all new to me so bear with me.
blkdev_open() calls
do_open(bdev, ...,BD_MUTEX_NORMAL) and takes
mutex_lock_nested(&bdev->bd_mutex, BD_MUTEX_NORMAL)
then something fails, and we're thrown to:
out_first: where
if (bdev != bdev->bd_contains)
blkdev_put(bdev->bd_contains) which is
__blkdev_put(bdev->bd_contains, BD_MUTEX_NORMAL) which does
mutex_lock_nested(&bdev->bd_contains->bd_mutex, BD_MUTEX_NORMAL) <--- lockdep trigger
When going to out_first, dbev->bd_contains is either bdev or whole, and
since we take the branch it must be whole. So it seems to me the
following patch would be the right one:
[akpm@xxxxxxxx: compile fix]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>
Acked-by: NeilBrown <neilb@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
fs/block_dev.c | 114 +++++++++++++++++++++++------------------------
1 file changed, 56 insertions(+), 58 deletions(-)
diff -puN fs/block_dev.c~lockdep-fix-blkdev_open-warning fs/block_dev.c
--- a/fs/block_dev.c~lockdep-fix-blkdev_open-warning
+++ a/fs/block_dev.c
@@ -884,6 +884,61 @@ void bd_set_size(struct block_device *bd
}
EXPORT_SYMBOL(bd_set_size);
+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_nested(&bdev->bd_mutex, subclass);
+ lock_kernel();
+ if (!--bdev->bd_openers) {
+ sync_blockdev(bdev);
+ kill_bdev(bdev);
+ }
+ if (bdev->bd_contains == bdev) {
+ if (disk->fops->release)
+ ret = disk->fops->release(bd_inode, NULL);
+ } else {
+ mutex_lock_nested(&bdev->bd_contains->bd_mutex,
+ subclass + 1);
+ bdev->bd_contains->bd_part_count--;
+ mutex_unlock(&bdev->bd_contains->bd_mutex);
+ }
+ if (!bdev->bd_openers) {
+ struct module *owner = disk->fops->owner;
+
+ put_disk(disk);
+ module_put(owner);
+
+ if (bdev->bd_contains != bdev) {
+ kobject_put(&bdev->bd_part->kobj);
+ bdev->bd_part = NULL;
+ }
+ 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, subclass + 1);
+ bdev->bd_contains = NULL;
+ }
+ unlock_kernel();
+ mutex_unlock(&bdev->bd_mutex);
+ bdput(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_get_whole(struct block_device *bdev, mode_t mode, unsigned flags);
@@ -980,7 +1035,7 @@ out_first:
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);
+ __blkdev_put(bdev->bd_contains, BD_MUTEX_WHOLE);
bdev->bd_contains = NULL;
put_disk(disk);
module_put(owner);
@@ -1079,63 +1134,6 @@ static int blkdev_open(struct inode * in
return res;
}
-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_nested(&bdev->bd_mutex, subclass);
- lock_kernel();
- if (!--bdev->bd_openers) {
- sync_blockdev(bdev);
- kill_bdev(bdev);
- }
- if (bdev->bd_contains == bdev) {
- if (disk->fops->release)
- ret = disk->fops->release(bd_inode, NULL);
- } else {
- mutex_lock_nested(&bdev->bd_contains->bd_mutex,
- subclass + 1);
- bdev->bd_contains->bd_part_count--;
- mutex_unlock(&bdev->bd_contains->bd_mutex);
- }
- if (!bdev->bd_openers) {
- struct module *owner = disk->fops->owner;
-
- put_disk(disk);
- module_put(owner);
-
- if (bdev->bd_contains != bdev) {
- kobject_put(&bdev->bd_part->kobj);
- bdev->bd_part = NULL;
- }
- 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, subclass + 1);
- bdev->bd_contains = NULL;
- }
- unlock_kernel();
- mutex_unlock(&bdev->bd_mutex);
- bdput(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);
_
Patches currently in -mm which might be from a.p.zijlstra@xxxxxxxxx are
mm-tracking-shared-dirty-pages.patch
mm-balance-dirty-pages.patch
mm-optimize-the-new-mprotect-code-a-bit.patch
mm-small-cleanup-of-install_page.patch
mm-fixup-do_wp_page.patch
mm-msync-cleanup.patch
mm-tracking-shared-dirty-pages-checks.patch
mm-tracking-shared-dirty-pages-wimp.patch
mm-swap-write-failure-fixup.patch
mm-swap-write-failure-fixup-update.patch
mm-swap-write-failure-fixup-fix.patch
block_devc-mutex_lock_nested-fix.patch
nfsd-lockdep-annotation.patch
-
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