Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965770AbeAOMkj (ORCPT + 1 other); Mon, 15 Jan 2018 07:40:39 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:46700 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965147AbeAOMkf (ORCPT ); Mon, 15 Jan 2018 07:40:35 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Takashi Iwai Subject: [PATCH 4.4 20/87] ALSA: pcm: Allow aborting mutex lock at OSS read/write loops Date: Mon, 15 Jan 2018 13:34:19 +0100 Message-Id: <20180115123351.309626066@linuxfoundation.org> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20180115123349.252309699@linuxfoundation.org> References: <20180115123349.252309699@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Takashi Iwai commit 900498a34a3ac9c611e9b425094c8106bdd7dc1c upstream. PCM OSS read/write loops keep taking the mutex lock for the whole read/write, and this might take very long when the exceptionally high amount of data is given. Also, since it invokes with mutex_lock(), the concurrent read/write becomes unbreakable. This patch tries to address these issues by replacing mutex_lock() with mutex_lock_interruptible(), and also splits / re-takes the lock at each read/write period chunk, so that it can switch the context more finely if requested. Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/core/oss/pcm_oss.c | 36 +++++++++++++++++++++--------------- 1 file changed, 21 insertions(+), 15 deletions(-) --- a/sound/core/oss/pcm_oss.c +++ b/sound/core/oss/pcm_oss.c @@ -1369,8 +1369,11 @@ static ssize_t snd_pcm_oss_write1(struct if ((tmp = snd_pcm_oss_make_ready(substream)) < 0) return tmp; - mutex_lock(&runtime->oss.params_lock); while (bytes > 0) { + if (mutex_lock_interruptible(&runtime->oss.params_lock)) { + tmp = -ERESTARTSYS; + break; + } if (bytes < runtime->oss.period_bytes || runtime->oss.buffer_used > 0) { tmp = bytes; if (tmp + runtime->oss.buffer_used > runtime->oss.period_bytes) @@ -1414,18 +1417,18 @@ static ssize_t snd_pcm_oss_write1(struct xfer += tmp; if ((substream->f_flags & O_NONBLOCK) != 0 && tmp != runtime->oss.period_bytes) - break; + tmp = -EAGAIN; } + err: + mutex_unlock(&runtime->oss.params_lock); + if (tmp < 0) + break; if (signal_pending(current)) { tmp = -ERESTARTSYS; - goto err; + break; } + tmp = 0; } - mutex_unlock(&runtime->oss.params_lock); - return xfer; - - err: - mutex_unlock(&runtime->oss.params_lock); return xfer > 0 ? (snd_pcm_sframes_t)xfer : tmp; } @@ -1473,8 +1476,11 @@ static ssize_t snd_pcm_oss_read1(struct if ((tmp = snd_pcm_oss_make_ready(substream)) < 0) return tmp; - mutex_lock(&runtime->oss.params_lock); while (bytes > 0) { + if (mutex_lock_interruptible(&runtime->oss.params_lock)) { + tmp = -ERESTARTSYS; + break; + } if (bytes < runtime->oss.period_bytes || runtime->oss.buffer_used > 0) { if (runtime->oss.buffer_used == 0) { tmp = snd_pcm_oss_read2(substream, runtime->oss.buffer, runtime->oss.period_bytes, 1); @@ -1505,16 +1511,16 @@ static ssize_t snd_pcm_oss_read1(struct bytes -= tmp; xfer += tmp; } + err: + mutex_unlock(&runtime->oss.params_lock); + if (tmp < 0) + break; if (signal_pending(current)) { tmp = -ERESTARTSYS; - goto err; + break; } + tmp = 0; } - mutex_unlock(&runtime->oss.params_lock); - return xfer; - - err: - mutex_unlock(&runtime->oss.params_lock); return xfer > 0 ? (snd_pcm_sframes_t)xfer : tmp; }