From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753613AbeE3Lhl (ORCPT ); Wed, 30 May 2018 07:37:41 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:60788 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752291AbeE3LHB (ORCPT ); Wed, 30 May 2018 07:07:01 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Takashi Iwai" Date: Wed, 30 May 2018 11:52:41 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 124/153] ALSA: seq: Clear client entry before deleting else at closing In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.102-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Takashi Iwai commit a2ff19f7b70118ced291a28d5313469914de451b upstream. When releasing a client, we need to clear the clienttab[] entry at first, then call snd_seq_queue_client_leave(). Otherwise, the in-flight cell in the queue might be picked up by the timer interrupt via snd_seq_check_queue() before calling snd_seq_queue_client_leave(), and it's delivered to another queue while the client is clearing queues. This may eventually result in an uncleared cell remaining in a queue, and the later snd_seq_pool_delete() may need to wait for a long time until the event gets really processed. By moving the clienttab[] clearance at the beginning of release, any event delivery of a cell belonging to this client will fail at a later point, since snd_seq_client_ptr() returns NULL. Thus the cell that was picked up by the timer interrupt will be returned immediately without further delivery, and the long stall of snd_seq_delete_pool() can be avoided, too. Signed-off-by: Takashi Iwai Signed-off-by: Ben Hutchings --- sound/core/seq/seq_clientmgr.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/sound/core/seq/seq_clientmgr.c +++ b/sound/core/seq/seq_clientmgr.c @@ -270,12 +270,12 @@ static int seq_free_client1(struct snd_s if (!client) return 0; - snd_seq_delete_all_ports(client); - snd_seq_queue_client_leave(client->number); spin_lock_irqsave(&clients_lock, flags); clienttablock[client->number] = 1; clienttab[client->number] = NULL; spin_unlock_irqrestore(&clients_lock, flags); + snd_seq_delete_all_ports(client); + snd_seq_queue_client_leave(client->number); snd_use_lock_sync(&client->use_lock); snd_seq_queue_client_termination(client->number); if (client->pool)