From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_NEOMUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B3DDCC169C4 for ; Fri, 8 Feb 2019 21:12:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8984420855 for ; Fri, 8 Feb 2019 21:12:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726949AbfBHVMc (ORCPT ); Fri, 8 Feb 2019 16:12:32 -0500 Received: from gofer.mess.org ([88.97.38.141]:60581 "EHLO gofer.mess.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726524AbfBHVMc (ORCPT ); Fri, 8 Feb 2019 16:12:32 -0500 Received: by gofer.mess.org (Postfix, from userid 1000) id 22C42601F7; Fri, 8 Feb 2019 21:12:31 +0000 (GMT) Date: Fri, 8 Feb 2019 21:12:30 +0000 From: Sean Young To: hverkuil-cisco@xs4all.nl Cc: linux-media@vger.kernel.org, Michael Ira Krufky , Brad Love , Sakari Ailus Subject: Re: [RFC PATCH 8/8] dvb-core: fix epoll() by calling poll_wait first Message-ID: <20190208211230.xznkkm7ucw7jn3h4@gofer.mess.org> References: <20190207114948.37750-1-hverkuil-cisco@xs4all.nl> <20190207114948.37750-9-hverkuil-cisco@xs4all.nl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190207114948.37750-9-hverkuil-cisco@xs4all.nl> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On Thu, Feb 07, 2019 at 12:49:48PM +0100, hverkuil-cisco@xs4all.nl wrote: > From: Hans Verkuil > > The epoll function expects that whenever the poll file op is > called, the poll_wait function is also called. That didn't > always happen in dvb_demux_poll(), dvb_dvr_poll() and > dvb_ca_en50221_io_poll(). Fix this, otherwise epoll() > can timeout when it shouldn't. > > Signed-off-by: Hans Verkuil Reviewed-by: Sean Young > --- > drivers/media/dvb-core/dmxdev.c | 8 ++++---- > drivers/media/dvb-core/dvb_ca_en50221.c | 5 ++--- > 2 files changed, 6 insertions(+), 7 deletions(-) > > diff --git a/drivers/media/dvb-core/dmxdev.c b/drivers/media/dvb-core/dmxdev.c > index 1544e8cef564..f14a872d1268 100644 > --- a/drivers/media/dvb-core/dmxdev.c > +++ b/drivers/media/dvb-core/dmxdev.c > @@ -1195,13 +1195,13 @@ static __poll_t dvb_demux_poll(struct file *file, poll_table *wait) > struct dmxdev_filter *dmxdevfilter = file->private_data; > __poll_t mask = 0; > > + poll_wait(file, &dmxdevfilter->buffer.queue, wait); > + > if ((!dmxdevfilter) || dmxdevfilter->dev->exit) > return EPOLLERR; > if (dvb_vb2_is_streaming(&dmxdevfilter->vb2_ctx)) > return dvb_vb2_poll(&dmxdevfilter->vb2_ctx, file, wait); > > - poll_wait(file, &dmxdevfilter->buffer.queue, wait); > - > if (dmxdevfilter->state != DMXDEV_STATE_GO && > dmxdevfilter->state != DMXDEV_STATE_DONE && > dmxdevfilter->state != DMXDEV_STATE_TIMEDOUT) > @@ -1346,13 +1346,13 @@ static __poll_t dvb_dvr_poll(struct file *file, poll_table *wait) > > dprintk("%s\n", __func__); > > + poll_wait(file, &dmxdev->dvr_buffer.queue, wait); > + > if (dmxdev->exit) > return EPOLLERR; > if (dvb_vb2_is_streaming(&dmxdev->dvr_vb2_ctx)) > return dvb_vb2_poll(&dmxdev->dvr_vb2_ctx, file, wait); > > - poll_wait(file, &dmxdev->dvr_buffer.queue, wait); > - > if (((file->f_flags & O_ACCMODE) == O_RDONLY) || > dmxdev->may_do_mmap) { > if (dmxdev->dvr_buffer.error) > diff --git a/drivers/media/dvb-core/dvb_ca_en50221.c b/drivers/media/dvb-core/dvb_ca_en50221.c > index 4d371cea0d5d..ebf1e3b03819 100644 > --- a/drivers/media/dvb-core/dvb_ca_en50221.c > +++ b/drivers/media/dvb-core/dvb_ca_en50221.c > @@ -1797,6 +1797,8 @@ static __poll_t dvb_ca_en50221_io_poll(struct file *file, poll_table *wait) > > dprintk("%s\n", __func__); > > + poll_wait(file, &ca->wait_queue, wait); > + > if (dvb_ca_en50221_io_read_condition(ca, &result, &slot) == 1) > mask |= EPOLLIN; > > @@ -1804,9 +1806,6 @@ static __poll_t dvb_ca_en50221_io_poll(struct file *file, poll_table *wait) > if (mask) > return mask; > > - /* wait for something to happen */ > - poll_wait(file, &ca->wait_queue, wait); > - > if (dvb_ca_en50221_io_read_condition(ca, &result, &slot) == 1) > mask |= EPOLLIN; > > -- > 2.20.1