From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tsutomu Itoh Subject: Re: [PATCH 05/12] btrfs: remove useless mutex lock/unlock sequences Date: Mon, 25 Apr 2011 15:25:58 +0900 Message-ID: <4DB513F6.6040503@jp.fujitsu.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-2022-JP Cc: linux-btrfs@vger.kernel.org, Chris Mason To: David Sterba Return-path: In-Reply-To: List-ID: (2011/04/22 18:41), David Sterba wrote: > Signed-off-by: David Sterba > --- > fs/btrfs/extent-tree.c | 6 ------ > 1 files changed, 0 insertions(+), 6 deletions(-) > > diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c > index 31f33ba..c97ceab 100644 > --- a/fs/btrfs/extent-tree.c > +++ b/fs/btrfs/extent-tree.c > @@ -756,8 +756,6 @@ again: > > btrfs_release_path(root->fs_info->extent_root, path); > > - mutex_lock(&head->mutex); > - mutex_unlock(&head->mutex); > btrfs_put_delayed_ref(&head->node); > goto again; This code tests whether the mutex_lock can be acquired, and when the mutex_lock can be taken, it try again. So I think that it is not a meaningless code. Thanks, Tsutomu > } > @@ -2297,8 +2295,6 @@ again: > atomic_inc(&ref->refs); > > spin_unlock(&delayed_refs->lock); > - mutex_lock(&head->mutex); > - mutex_unlock(&head->mutex); > > btrfs_put_delayed_ref(ref); > cond_resched(); > @@ -2363,8 +2359,6 @@ static noinline int check_delayed_ref(struct btrfs_trans_handle *trans, > > btrfs_release_path(root->fs_info->extent_root, path); > > - mutex_lock(&head->mutex); > - mutex_unlock(&head->mutex); > btrfs_put_delayed_ref(&head->node); > return -EAGAIN; > }