[{"id":21873,"web_url":"https://patchwork.libcamera.org/comment/21873/","msgid":"<164026631773.3986460.4663830835669940653@Monstersaurus>","date":"2021-12-23T13:31:57","subject":"Re: [libcamera-devel] [PATCH 1/2] libcamera: media_device: Move\n\trecursive lock handling to pipeline handler","submitter":{"id":4,"url":"https://patchwork.libcamera.org/api/people/4/","name":"Kieran Bingham","email":"kieran.bingham@ideasonboard.com"},"content":"Quoting Laurent Pinchart (2021-12-23 02:33:30)\n> The MediaDevice lock is meant to prevent concurrent usage of multiple\n> cameras from the same pipeline handlers. As media devices are acquired\n> by pipeline handlers, we can't have multiple pipeline handlers trying to\n> lock the same media device. The recursive locking detection can thus be\n> moved to the pipeline handler. This simplifies the media device\n> implementation that now implements true lock semantics, and prepares for\n> support of concurrent camera usage.\n> \n> Signed-off-by: Laurent Pinchart \n> ---\n> include/libcamera/internal/media_device.h | 1 -\n> include/libcamera/internal/pipeline_handler.h | 2 ++\n> src/libcamera/media_device.cpp | 14 +-------------\n> src/libcamera/pipeline_handler.cpp | 13 ++++++++++++-\n> 4 files changed, 15 insertions(+), 15 deletions(-)\n> \n> diff --git a/include/libcamera/internal/media_device.h b/include/libcamera/internal/media_device.h\n> index af0b25b731eb..6e2a63f38229 100644\n> --- a/include/libcamera/internal/media_device.h\n> +++ b/include/libcamera/internal/media_device.h\n> @@ -86,7 +86,6 @@ private:\n> UniqueFD fd_;\n> bool valid_;\n> bool acquired_;\n> - bool lockOwner_;\n> \n> std::map objects_;\n> std::vector entities_;\n> diff --git a/include/libcamera/internal/pipeline_handler.h b/include/libcamera/internal/pipeline_handler.h\n> index ec986a518b5c..a7331cedfb16 100644\n> --- a/include/libcamera/internal/pipeline_handler.h\n> +++ b/include/libcamera/internal/pipeline_handler.h\n> @@ -88,6 +88,8 @@ private:\n> \n> const char *name_;\n> \n> + bool lockOwner_;\n> +\n> friend class PipelineHandlerFactory;\n> };\n> \n> diff --git a/src/libcamera/media_device.cpp b/src/libcamera/media_device.cpp\n> index 0b7940182d0c..941f86c25f66 100644\n> --- a/src/libcamera/media_device.cpp\n> +++ b/src/libcamera/media_device.cpp\n> @@ -63,8 +63,7 @@ LOG_DEFINE_CATEGORY(MediaDevice)\n> * populate() before the media graph can be queried.\n> */\n> MediaDevice::MediaDevice(const std::string &deviceNode)\n> - : deviceNode_(deviceNode), valid_(false), acquired_(false),\n> - lockOwner_(false)\n> + : deviceNode_(deviceNode), valid_(false), acquired_(false)\n> {\n> }\n> \n> @@ -145,15 +144,9 @@ bool MediaDevice::lock()\n> if (!fd_.isValid())\n> return false;\n> \n> - /* Do not allow nested locking in the same libcamera instance. */\n> - if (lockOwner_)\n> - return false;\n> -\n> if (lockf(fd_.get(), F_TLOCK, 0))\n> return false;\n> \n> - lockOwner_ = true;\n> -\n> return true;\n> }\n> \n> @@ -171,11 +164,6 @@ void MediaDevice::unlock()\n> if (!fd_.isValid())\n> return;\n> \n> - if (!lockOwner_)\n> - return;\n> -\n> - lockOwner_ = false;\n> -\n> lockf(fd_.get(), F_ULOCK, 0);\n> }\n> \n> diff --git a/src/libcamera/pipeline_handler.cpp b/src/libcamera/pipeline_handler.cpp\n> index 0bc0e341b9e7..b2ee4ec0ce87 100644\n> --- a/src/libcamera/pipeline_handler.cpp\n> +++ b/src/libcamera/pipeline_handler.cpp\n> @@ -67,7 +67,7 @@ LOG_DEFINE_CATEGORY(Pipeline)\n> * respective factories.\n> */\n> PipelineHandler::PipelineHandler(CameraManager *manager)\n> - : manager_(manager)\n> + : manager_(manager), lockOwner_(false)\n> {\n> }\n> \n> @@ -155,6 +155,10 @@ MediaDevice *PipelineHandler::acquireMediaDevice(DeviceEnumerator *enumerator,\n> */\n> bool PipelineHandler::lock()\n> {\n> + /* Do not allow nested locking in the same libcamera instance. */\n> + if (lockOwner_)\n> + return false;\n> +\n> for (std::shared_ptr &media : mediaDevices_) {\n> if (!media->lock()) {\n> unlock();\n> @@ -162,6 +166,8 @@ bool PipelineHandler::lock()\n> }\n> }\n> \n> + lockOwner_ = true;\n> +\n> return true;\n> }\n> \n> @@ -177,8 +183,13 @@ bool PipelineHandler::lock()\n> */\n> void PipelineHandler::unlock()\n> {\n> + if (lockOwner_)\n\n if (!lockOwner_) ?\n\n\n> + return;\n> +\n> for (std::shared_ptr &media : mediaDevices_)\n> media->unlock();\n> +\n> + lockOwner_ = false;\n> }\n> \n> /**\n> -- \n> Regards,\n> \n> Laurent Pinchart\n>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 0A7A1BF415\n\tfor ;\n\tThu, 23 Dec 2021 13:32:03 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 3CCAA60115;\n\tThu, 23 Dec 2021 14:32:02 +0100 (CET)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 26F8660115\n\tfor ;\n\tThu, 23 Dec 2021 14:32:00 +0100 (CET)","from pendragon.ideasonboard.com\n\t(cpc89244-aztw30-2-0-cust3082.18-1.cable.virginm.net [86.31.172.11])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id AFAF42C5;\n\tThu, 23 Dec 2021 14:31:59 +0100 (CET)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"h2e3poPi\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1640266319;\n\tbh=aCpRfC1Omf2OP8I/w1sqNXpddOGFtrG13z7J4MjQFsM=;\n\th=In-Reply-To:References:Subject:From:To:Date:From;\n\tb=h2e3poPiAwW8iL3Y+E+0ePKmfGECIcj3ygeiTmwAYexNbrIKEUA6MwXIlcryz8QPg\n\tOGO4aTMWZtqqk4RnvAaGLHTu4O6SBQ9F8OD1Aq/9BE0XvJy8kpTNA0jNilMTub4lPg\n\tqd3cNTNT9BPurN+2iDJwHGMw0/OxN5GBSEKoYWq0=","Content-Type":"text/plain; charset=\"utf-8\"","MIME-Version":"1.0","Content-Transfer-Encoding":"quoted-printable","In-Reply-To":"<20211223023331.13505-2-laurent.pinchart@ideasonboard.com>","References":"<20211223023331.13505-1-laurent.pinchart@ideasonboard.com>\n\t<20211223023331.13505-2-laurent.pinchart@ideasonboard.com>","From":"Kieran Bingham ","To":"Laurent Pinchart ,\n\tlibcamera-devel@lists.libcamera.org","Date":"Thu, 23 Dec 2021 13:31:57 +0000","Message-ID":"<164026631773.3986460.4663830835669940653@Monstersaurus>","User-Agent":"alot/0.10","Subject":"Re: [libcamera-devel] [PATCH 1/2] libcamera: media_device: Move\n\trecursive lock handling to pipeline handler","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":21878,"web_url":"https://patchwork.libcamera.org/comment/21878/","msgid":"","date":"2021-12-26T22:03:04","subject":"Re: [libcamera-devel] [PATCH 1/2] libcamera: media_device: Move\n\trecursive lock handling to pipeline handler","submitter":{"id":2,"url":"https://patchwork.libcamera.org/api/people/2/","name":"Laurent Pinchart","email":"laurent.pinchart@ideasonboard.com"},"content":"On Thu, Dec 23, 2021 at 01:31:57PM +0000, Kieran Bingham wrote:\n> Quoting Laurent Pinchart (2021-12-23 02:33:30)\n> > The MediaDevice lock is meant to prevent concurrent usage of multiple\n> > cameras from the same pipeline handlers. As media devices are acquired\n> > by pipeline handlers, we can't have multiple pipeline handlers trying to\n> > lock the same media device. The recursive locking detection can thus be\n> > moved to the pipeline handler. This simplifies the media device\n> > implementation that now implements true lock semantics, and prepares for\n> > support of concurrent camera usage.\n> > \n> > Signed-off-by: Laurent Pinchart \n> > ---\n> > include/libcamera/internal/media_device.h | 1 -\n> > include/libcamera/internal/pipeline_handler.h | 2 ++\n> > src/libcamera/media_device.cpp | 14 +-------------\n> > src/libcamera/pipeline_handler.cpp | 13 ++++++++++++-\n> > 4 files changed, 15 insertions(+), 15 deletions(-)\n> > \n> > diff --git a/include/libcamera/internal/media_device.h b/include/libcamera/internal/media_device.h\n> > index af0b25b731eb..6e2a63f38229 100644\n> > --- a/include/libcamera/internal/media_device.h\n> > +++ b/include/libcamera/internal/media_device.h\n> > @@ -86,7 +86,6 @@ private:\n> > UniqueFD fd_;\n> > bool valid_;\n> > bool acquired_;\n> > - bool lockOwner_;\n> > \n> > std::map objects_;\n> > std::vector entities_;\n> > diff --git a/include/libcamera/internal/pipeline_handler.h b/include/libcamera/internal/pipeline_handler.h\n> > index ec986a518b5c..a7331cedfb16 100644\n> > --- a/include/libcamera/internal/pipeline_handler.h\n> > +++ b/include/libcamera/internal/pipeline_handler.h\n> > @@ -88,6 +88,8 @@ private:\n> > \n> > const char *name_;\n> > \n> > + bool lockOwner_;\n> > +\n> > friend class PipelineHandlerFactory;\n> > };\n> > \n> > diff --git a/src/libcamera/media_device.cpp b/src/libcamera/media_device.cpp\n> > index 0b7940182d0c..941f86c25f66 100644\n> > --- a/src/libcamera/media_device.cpp\n> > +++ b/src/libcamera/media_device.cpp\n> > @@ -63,8 +63,7 @@ LOG_DEFINE_CATEGORY(MediaDevice)\n> > * populate() before the media graph can be queried.\n> > */\n> > MediaDevice::MediaDevice(const std::string &deviceNode)\n> > - : deviceNode_(deviceNode), valid_(false), acquired_(false),\n> > - lockOwner_(false)\n> > + : deviceNode_(deviceNode), valid_(false), acquired_(false)\n> > {\n> > }\n> > \n> > @@ -145,15 +144,9 @@ bool MediaDevice::lock()\n> > if (!fd_.isValid())\n> > return false;\n> > \n> > - /* Do not allow nested locking in the same libcamera instance. */\n> > - if (lockOwner_)\n> > - return false;\n> > -\n> > if (lockf(fd_.get(), F_TLOCK, 0))\n> > return false;\n> > \n> > - lockOwner_ = true;\n> > -\n> > return true;\n> > }\n> > \n> > @@ -171,11 +164,6 @@ void MediaDevice::unlock()\n> > if (!fd_.isValid())\n> > return;\n> > \n> > - if (!lockOwner_)\n> > - return;\n> > -\n> > - lockOwner_ = false;\n> > -\n> > lockf(fd_.get(), F_ULOCK, 0);\n> > }\n> > \n> > diff --git a/src/libcamera/pipeline_handler.cpp b/src/libcamera/pipeline_handler.cpp\n> > index 0bc0e341b9e7..b2ee4ec0ce87 100644\n> > --- a/src/libcamera/pipeline_handler.cpp\n> > +++ b/src/libcamera/pipeline_handler.cpp\n> > @@ -67,7 +67,7 @@ LOG_DEFINE_CATEGORY(Pipeline)\n> > * respective factories.\n> > */\n> > PipelineHandler::PipelineHandler(CameraManager *manager)\n> > - : manager_(manager)\n> > + : manager_(manager), lockOwner_(false)\n> > {\n> > }\n> > \n> > @@ -155,6 +155,10 @@ MediaDevice *PipelineHandler::acquireMediaDevice(DeviceEnumerator *enumerator,\n> > */\n> > bool PipelineHandler::lock()\n> > {\n> > + /* Do not allow nested locking in the same libcamera instance. */\n> > + if (lockOwner_)\n> > + return false;\n> > +\n> > for (std::shared_ptr &media : mediaDevices_) {\n> > if (!media->lock()) {\n> > unlock();\n> > @@ -162,6 +166,8 @@ bool PipelineHandler::lock()\n> > }\n> > }\n> > \n> > + lockOwner_ = true;\n> > +\n> > return true;\n> > }\n> > \n> > @@ -177,8 +183,13 @@ bool PipelineHandler::lock()\n> > */\n> > void PipelineHandler::unlock()\n> > {\n> > + if (lockOwner_)\n> \n> if (!lockOwner_) ?\n\nOops, indeed. I'll fix it in v2.\n\n> > + return;\n> > +\n> > for (std::shared_ptr &media : mediaDevices_)\n> > media->unlock();\n> > +\n> > + lockOwner_ = false;\n> > }\n> > \n> > /**","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 1F8C6BF415\n\tfor ;\n\tSun, 26 Dec 2021 22:03:10 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id DAAA560911;\n\tSun, 26 Dec 2021 23:03:08 +0100 (CET)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 014F66021B\n\tfor ;\n\tSun, 26 Dec 2021 23:03:07 +0100 (CET)","from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi\n\t[62.78.145.57])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 6CEBB3E7;\n\tSun, 26 Dec 2021 23:03:07 +0100 (CET)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"inTPXNNg\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1640556187;\n\tbh=roMScVh5wI6GmU6EJRFipUhI3NbruMUW6ZkvEKw+nl4=;\n\th=Date:From:To:Cc:Subject:References:In-Reply-To:From;\n\tb=inTPXNNgY4jqmoUn+Ig701Wx4ynatUXgS1b7oISkISdLMkXj07RpgF4y/CliH7C6H\n\tEOezX/V/Dq/lbvDBjW63rIWzJfGbhqGWQuMU7qaWg/MqlelVsSMKPNfAnLpHe4maVd\n\tJk/P3JM30/XvHHYMw4WOxLETB8kgOWIb4o7RKvZE=","Date":"Mon, 27 Dec 2021 00:03:04 +0200","From":"Laurent Pinchart ","To":"Kieran Bingham ","Message-ID":"","References":"<20211223023331.13505-1-laurent.pinchart@ideasonboard.com>\n\t<20211223023331.13505-2-laurent.pinchart@ideasonboard.com>\n\t<164026631773.3986460.4663830835669940653@Monstersaurus>","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Disposition":"inline","In-Reply-To":"<164026631773.3986460.4663830835669940653@Monstersaurus>","Subject":"Re: [libcamera-devel] [PATCH 1/2] libcamera: media_device: Move\n\trecursive lock handling to pipeline handler","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Cc":"libcamera-devel@lists.libcamera.org","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}}]