[{"id":16976,"web_url":"https://patchwork.libcamera.org/comment/16976/","msgid":"","date":"2021-05-17T04:53:45","subject":"Re: [libcamera-devel] [PATCH v2 6/8] android: Guard access to the\n\tcamera state","submitter":{"id":63,"url":"https://patchwork.libcamera.org/api/people/63/","name":"Hirokazu Honda","email":"hiroh@chromium.org"},"content":"Hi Jacopo, thank you for the patch.\n\nOn Thu, May 13, 2021 at 6:22 PM Jacopo Mondi wrote:\n\n> Guard access to the camera state and the start/stop sequences\n> with a mutex.\n>\n> Currently only stop() and the first call to processCaptureRequest()\n> start and stop the camera, and they're not meant to race with each\n> other. With the introduction of flush() the camera can be stopped\n> concurrently to a processCaptureRequest() call, hence access to the\n> camera state will need to be protected.\n>\n> Prepare for that by guarding the existing paths with a mutex.\n>\n> Signed-off-by: Jacopo Mondi \n> Reviewed-by: Niklas Söderlund \n> ---\n> src/android/camera_device.cpp | 23 ++++++++++++++---------\n> src/android/camera_device.h | 1 +\n> 2 files changed, 15 insertions(+), 9 deletions(-)\n>\n> diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp\n> index 8a4543f079eb..c6cd0b6e8be7 100644\n> --- a/src/android/camera_device.cpp\n> +++ b/src/android/camera_device.cpp\n> @@ -759,6 +759,7 @@ void CameraDevice::close()\n>\n> void CameraDevice::stop()\n> {\n> + MutexLocker cameraLock(cameraMutex_);\n> if (state_ == CameraStopped)\n> return;\n>\n> @@ -1915,17 +1916,21 @@ int\n> CameraDevice::processCaptureRequest(camera3_capture_request_t *camera3Reques\n> if (!isValidRequest(camera3Request))\n> return -EINVAL;\n>\n> - /* Start the camera if that's the first request we handle. */\n> - if (state_ == CameraStopped) {\n> - worker_.start();\n> + {\n> + MutexLocker cameraLock(cameraMutex_);\n>\n> - int ret = camera_->start();\n> - if (ret) {\n> - LOG(HAL, Error) << \"Failed to start camera\";\n> - return ret;\n> - }\n> + /* Start the camera if that's the first request we handle.\n> */\n> + if (state_ == CameraStopped) {\n> + worker_.start();\n>\n> - state_ = CameraRunning;\n> + int ret = camera_->start();\n> + if (ret) {\n> + LOG(HAL, Error) << \"Failed to start\n> camera\";\n> + return ret;\n> + }\n> +\n> + state_ = CameraRunning;\n> + }\n> }\n>\n> /*\n> diff --git a/src/android/camera_device.h b/src/android/camera_device.h\n> index 30b364decaab..f263fdae472a 100644\n> --- a/src/android/camera_device.h\n> +++ b/src/android/camera_device.h\n> @@ -120,6 +120,7 @@ private:\n>\n> CameraWorker worker_;\n>\n> + libcamera::Mutex cameraMutex_; /* Protects access to the camera\n> state. */\n>\n\nI wonder if this should be used to protect camera_ and worker_.\n\n\n> State state_;\n>\n> std::shared_ptr camera_;\n> --\n> 2.31.1\n>\n> _______________________________________________\n> libcamera-devel mailing list\n> libcamera-devel@lists.libcamera.org\n> https://lists.libcamera.org/listinfo/libcamera-devel\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 52092C31FC\n\tfor ;\n\tMon, 17 May 2021 04:54:00 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id C4C116891E;\n\tMon, 17 May 2021 06:53:59 +0200 (CEST)","from mail-ed1-x530.google.com (mail-ed1-x530.google.com\n\t[IPv6:2a00:1450:4864:20::530])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 2E9D3602B1\n\tfor ;\n\tMon, 17 May 2021 06:53:58 +0200 (CEST)","by mail-ed1-x530.google.com with SMTP id n25so5245953edr.5\n\tfor ;\n\tSun, 16 May 2021 21:53:58 -0700 (PDT)"],"Authentication-Results":"lancelot.ideasonboard.com; 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\n\tSun, 16 May 2021 21:53:57 -0700 (PDT)","MIME-Version":"1.0","References":"<20210513092246.42847-1-jacopo@jmondi.org>\n\t<20210513092246.42847-7-jacopo@jmondi.org>","In-Reply-To":"<20210513092246.42847-7-jacopo@jmondi.org>","From":"Hirokazu Honda ","Date":"Mon, 17 May 2021 13:53:45 +0900","Message-ID":"","To":"Jacopo Mondi ","Content-Type":"multipart/alternative; boundary=\"0000000000009d805c05c27f61da\"","Subject":"Re: [libcamera-devel] [PATCH v2 6/8] android: Guard access to the\n\tcamera state","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 ","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}}]