s_active is released by the thread doing the final sysfs_put() which
can be different from the thread which did sysfs_deactivate(). Make
lockdep think that s_active is unlocked immediately after it's write
locked.
Signed-off-by: Tejun Heo <[EMAIL PROTECTED]>
---
Greg, this patch fixes lockdep error reported by Cornelia. Please add
this to the patch series. Andrew, this is the same one you took
earlier only with comments added.
Thanks.
fs/sysfs/dir.c | 7 ++++++-
fs/sysfs/sysfs.h | 5 +++++
2 files changed, 11 insertions(+), 1 deletion(-)
Index: work/fs/sysfs/dir.c
===================================================================
--- work.orig/fs/sysfs/dir.c
+++ work/fs/sysfs/dir.c
@@ -25,8 +25,13 @@ void release_sysfs_dirent(struct sysfs_d
/* If @sd is being released after deletion, s_active is write
* locked. If @sd is cursor for directory walk or being
* released prematurely, s_active has no reader or writer.
+ *
+ * sysfs_deactivate() lies to lockdep that s_active is
+ * unlocked immediately. Lie one more time to cover the
+ * previous lie.
*/
- down_write_trylock(&sd->s_active);
+ if (!down_write_trylock(&sd->s_active))
+ rwsem_acquire(&sd->s_active.dep_map, 0, 0, _RET_IP_);
up_write(&sd->s_active);
if (sd->s_type & SYSFS_KOBJ_LINK)
Index: work/fs/sysfs/sysfs.h
===================================================================
--- work.orig/fs/sysfs/sysfs.h
+++ work/fs/sysfs/sysfs.h
@@ -171,6 +171,11 @@ static inline void sysfs_put_active_two(
static inline void sysfs_deactivate(struct sysfs_dirent *sd)
{
down_write(&sd->s_active);
+
+ /* s_active will be unlocked by the thread doing the final put
+ * on @sd. Lie to lockdep.
+ */
+ rwsem_release(&sd->s_active.dep_map, 1, _RET_IP_);
}
static inline int sysfs_is_shadowed_inode(struct inode *inode)
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
