Revert "kernfs: make kernfs_get_active() block if the node is deactivated but not removed"
This reverts commit 895a068a524e134900b9d98b519309b7aae7bbb1.
Tejun writes:
I'm sorry but can you please revert the whole series?
get_active() waiting while a node is deactivated has potential
to lead to deadlock and that deactivate/reactivate interface is
something fundamentally flawed and that cgroup will have to work
with the remove_self() like everybody else. IOW, I think the
first posting was correct.
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 37dd640..770d687 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -149,25 +149,12 @@
if (unlikely(!kn))
return NULL;
+ if (!atomic_inc_unless_negative(&kn->active))
+ return NULL;
+
if (kernfs_lockdep(kn))
rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_);
-
- /*
- * Try to obtain an active ref. If @kn is deactivated, we block
- * till either it's reactivated or killed.
- */
- do {
- if (atomic_inc_unless_negative(&kn->active))
- return kn;
-
- wait_event(kernfs_root(kn)->deactivate_waitq,
- atomic_read(&kn->active) >= 0 ||
- RB_EMPTY_NODE(&kn->rb));
- } while (!RB_EMPTY_NODE(&kn->rb));
-
- if (kernfs_lockdep(kn))
- rwsem_release(&kn->dep_map, 1, _RET_IP_);
- return NULL;
+ return kn;
}
/**
@@ -799,7 +786,6 @@
static void __kernfs_remove(struct kernfs_node *kn)
{
- struct kernfs_root *root = kernfs_root(kn);
struct kernfs_node *pos;
lockdep_assert_held(&kernfs_mutex);
@@ -851,9 +837,6 @@
kernfs_put(pos);
} while (pos != kn);
-
- /* some nodes killed, kick get_active waiters */
- wake_up_all(&root->deactivate_waitq);
}
/**