From: Arjan van de Ven Date: Mon, 3 Jul 2006 07:25:21 +0000 (-0700) Subject: [PATCH] lockdep: annotate USBFS X-Git-Tag: v2.6.18-rc1~50 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8e7795ef6b5fd117b22b87ea7d501de2526a25f7;p=linux-2.6 [PATCH] lockdep: annotate USBFS 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. Has no effect on non-lockdep kernels. Signed-off-by: Arjan van de Ven Signed-off-by: Ingo Molnar Cc: Greg KH Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/drivers/usb/core/inode.c b/drivers/usb/core/inode.c index cf11196e01..f48c3dbc36 100644 --- a/drivers/usb/core/inode.c +++ b/drivers/usb/core/inode.c @@ -527,7 +527,7 @@ static void fs_remove_file (struct dentry *dentry) 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))