Messages in this thread Patch in this message | | | Subject | [Patch] Lockdep: add parent-child annotations to usbfs | From | Arjan van de Ven <> | Date | Fri, 02 Jun 2006 08:49:09 +0200 |
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Hi,
In usbfs's fs_remove_file() function, the aim is to remove a file or directory from usbfs. This is done by first taking the i_mutex of the parent directory of this file/dir via mutex_lock(&parent->d_inode->i_mutex); and then to call either usbfs_rmdir() for a directory or usbfs_unlink() for a file. Both these functions then take the i_mutex for the to-be-removed object themselves: mutex_lock(&inode->i_mutex);
This is a classical parent->child locking order relationship that the VFS uses all over the place; the VFS locking rule is "you need to take the parent first". This patch annotates the usbfs code to make this explicit and thus informs the lockdep code that those two locks indeed have this relationship.
The rules for unlink that we already use in the VFS for unlink are to use I_MUTEX_PARENT for the parent directory, and a normal mutex for the file itself; this patch follows that convention.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
--- drivers/usb/core/inode.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
Index: linux-2.6.17-rc5-mm1.5/drivers/usb/core/inode.c =================================================================== --- linux-2.6.17-rc5-mm1.5.orig/drivers/usb/core/inode.c +++ linux-2.6.17-rc5-mm1.5/drivers/usb/core/inode.c
@@ -528,7 +528,7 @@ static void fs_remove_file (struct dentr if (!parent || !parent->d_inode) return; - mutex_lock(&parent->d_inode->i_mutex); + mutex_lock_nested(&parent->d_inode->i_mutex, I_MUTEX_PARENT); if (usbfs_positive(dentry)) { if (dentry->d_inode) { if (S_ISDIR(dentry->d_inode->i_mode)) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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