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| author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-01-14 02:39:52 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-01-14 02:39:52 +0400 |
| commit | 0890147fe09ff7e8275a162b1ab76ab5e3158c6d (patch) | |
| tree | 797d8beb9a38fb4580d2ad628571615528f18028 /fs | |
| parent | 798c75a0d44cdbd6e3d82a6a676e6de38525b3bb (diff) | |
| download | linux-0890147fe09ff7e8275a162b1ab76ab5e3158c6d.tar.xz | |
Revert "kernfs: remove KERNFS_ACTIVE_REF and add kernfs_lockdep()"
This reverts commit a69d001cfc712b96ec9d7ba44d6285702a38dabf.
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>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/kernfs/dir.c | 31 |
1 files changed, 11 insertions, 20 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index 1c9130a33048..ed62de6cdf8f 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -22,15 +22,6 @@ DEFINE_MUTEX(kernfs_mutex); #define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb) -static bool kernfs_lockdep(struct kernfs_node *kn) -{ -#ifdef CONFIG_DEBUG_LOCK_ALLOC - return kn->flags & KERNFS_LOCKDEP; -#else - return false; -#endif -} - /** * kernfs_name_hash * @name: Null terminated string to hash @@ -147,7 +138,7 @@ struct kernfs_node *kernfs_get_active(struct kernfs_node *kn) if (!atomic_inc_unless_negative(&kn->active)) return NULL; - if (kernfs_lockdep(kn)) + if (kn->flags & KERNFS_LOCKDEP) rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_); return kn; } @@ -167,7 +158,7 @@ void kernfs_put_active(struct kernfs_node *kn) if (unlikely(!kn)) return; - if (kernfs_lockdep(kn)) + if (kn->flags & KERNFS_LOCKDEP) rwsem_release(&kn->dep_map, 1, _RET_IP_); v = atomic_dec_return(&kn->active); if (likely(v != KN_DEACTIVATED_BIAS)) @@ -188,21 +179,21 @@ static void kernfs_deactivate(struct kernfs_node *kn) BUG_ON(!(kn->flags & KERNFS_REMOVED)); + if (!(kernfs_type(kn) & KERNFS_ACTIVE_REF)) + return; + + rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_); + atomic_add(KN_DEACTIVATED_BIAS, &kn->active); - if (kernfs_lockdep(kn)) { - rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_); - if (atomic_read(&kn->active) != KN_DEACTIVATED_BIAS) - lock_contended(&kn->dep_map, _RET_IP_); - } + if (atomic_read(&kn->active) != KN_DEACTIVATED_BIAS) + lock_contended(&kn->dep_map, _RET_IP_); wait_event(root->deactivate_waitq, atomic_read(&kn->active) == KN_DEACTIVATED_BIAS); - if (kernfs_lockdep(kn)) { - lock_acquired(&kn->dep_map, _RET_IP_); - rwsem_release(&kn->dep_map, 1, _RET_IP_); - } + lock_acquired(&kn->dep_map, _RET_IP_); + rwsem_release(&kn->dep_map, 1, _RET_IP_); } /** |