From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Trond Myklebust Subject: [PATCH 3.15 38/66] NFS: Use raw_write_seqcount_begin/end int nfs4_reclaim_open_state Date: Fri, 4 Jul 2014 15:14:37 -0700 Message-Id: <20140704221424.551732478@linuxfoundation.org> In-Reply-To: <20140704221422.813435485@linuxfoundation.org> References: <20140704221422.813435485@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Trond Myklebust commit abbec2da13f0e4c5d9b78b7e2c025a3e617228ba upstream. The addition of lockdep code to write_seqcount_begin/end has lead to a bunch of false positive claims of ABBA deadlocks with the so_lock spinlock. Audits show that this simply cannot happen because the read side code does not spin while holding so_lock. Signed-off-by: Trond Myklebust Signed-off-by: Greg Kroah-Hartman --- fs/nfs/nfs4state.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/fs/nfs/nfs4state.c +++ b/fs/nfs/nfs4state.c @@ -1456,7 +1456,7 @@ static int nfs4_reclaim_open_state(struc * server that doesn't support a grace period. */ spin_lock(&sp->so_lock); - write_seqcount_begin(&sp->so_reclaim_seqcount); + raw_write_seqcount_begin(&sp->so_reclaim_seqcount); restart: list_for_each_entry(state, &sp->so_states, open_states) { if (!test_and_clear_bit(ops->state_flag_bit, &state->flags)) @@ -1519,13 +1519,13 @@ restart: spin_lock(&sp->so_lock); goto restart; } - write_seqcount_end(&sp->so_reclaim_seqcount); + raw_write_seqcount_end(&sp->so_reclaim_seqcount); spin_unlock(&sp->so_lock); return 0; out_err: nfs4_put_open_state(state); spin_lock(&sp->so_lock); - write_seqcount_end(&sp->so_reclaim_seqcount); + raw_write_seqcount_end(&sp->so_reclaim_seqcount); spin_unlock(&sp->so_lock); return status; }