From patchwork Fri Aug 30 11:12:06 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hans de Goede X-Patchwork-Id: 21077 Return-Path: X-Original-To: parsemail@patchwork.libcamera.org Delivered-To: parsemail@patchwork.libcamera.org Received: from lancelot.ideasonboard.com (lancelot.ideasonboard.com [92.243.16.209]) by patchwork.libcamera.org (Postfix) with ESMTPS id CDC27C32C2 for ; Fri, 30 Aug 2024 11:12:29 +0000 (UTC) Received: from lancelot.ideasonboard.com (localhost [IPv6:::1]) by lancelot.ideasonboard.com (Postfix) with ESMTP id 4B519634CC; Fri, 30 Aug 2024 13:12:29 +0200 (CEST) Authentication-Results: lancelot.ideasonboard.com; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.b="YvWZqXTK"; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lancelot.ideasonboard.com (Postfix) with ESMTPS id 7ADAF6341E for ; Fri, 30 Aug 2024 13:12:24 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1725016343; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=sp6s1+UJtIvT5Ha33B41edOQJjVcHMpRWZ9VIqSlOas=; b=YvWZqXTKcXs2KwMx1M5H9raCS3/ps+cEQ446IUBT0aNI4cdlPNpGvlTyo9O+D3Bt3C4JR3 1461gp7YoZ70Xt86V1Rsg27t5sBsAOPQKz6A0H+TY1RWNruyQ9HRuvLdvsfTNv/wA9kKol 2g42Rk8EDozS+RT9Pf1SW9NxOoXQGjE= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-517-2B86pn5JPpizPv6TUk2FLQ-1; Fri, 30 Aug 2024 07:12:20 -0400 X-MC-Unique: 2B86pn5JPpizPv6TUk2FLQ-1 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.15]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 6970D1956064; Fri, 30 Aug 2024 11:12:19 +0000 (UTC) Received: from localhost.localdomain (unknown [10.39.193.217]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id CBCAD1955F1B; Fri, 30 Aug 2024 11:12:17 +0000 (UTC) From: Hans de Goede To: libcamera-devel@lists.libcamera.org Cc: Milan Zamazal , Maxime Ripard , Hans de Goede , Laurent Pinchart Subject: [PATCH v3 2/3] camera: Use invokeMethod() for pipe_->acquire() and pipe_->release() Date: Fri, 30 Aug 2024 13:12:06 +0200 Message-ID: <20240830111207.46455-3-hdegoede@redhat.com> In-Reply-To: <20240830111207.46455-1-hdegoede@redhat.com> References: <20240830111207.46455-1-hdegoede@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-BeenThere: libcamera-devel@lists.libcamera.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: libcamera-devel-bounces@lists.libcamera.org Sender: "libcamera-devel" The uvcvideo driver needs to open / close its /dev/video# node from pipe_->acquireDevices() / pipe_->releaseDevices(). V4L2VideoDevice::open() creates an EventNotifier and this notifier needs to be created from the CameraManager thread. Use invokeMethod() for pipe_->acquire() and pipe_->release() so that the EventNotifiers are created from the CameraManager thread context. Running pipe_->acquire() and pipe_->release() from the CameraManager thread context serializes all calls to them. Drop PipelineHandler::lock_ this now is no longer necessary and update the "\context" part of the documentation for acquire[Device]() and release[Device]() to match. Note the delayed opening of /dev/video# is a special case because the kernel uvcvideo driver powers on the USB device as soon as /dev/video# is opened. This behavior should *not* be copied by other pipeline handlers. Reviewed-by: Laurent Pinchart Signed-off-by: Hans de Goede --- Changes in v2: - Add a note to the commit message that opening/closing /dev/video# from acquire()/release() as the uvcvideo pipeline handler does is an exception and that this behavior should not be copied by other pipeline handlers - Drop lock_, update "\context" in doxygen docs --- include/libcamera/internal/pipeline_handler.h | 5 +---- src/libcamera/camera.cpp | 6 ++++-- src/libcamera/pipeline_handler.cpp | 12 ++++++------ 3 files changed, 11 insertions(+), 12 deletions(-) diff --git a/include/libcamera/internal/pipeline_handler.h b/include/libcamera/internal/pipeline_handler.h index 597f7c3e..c33cf715 100644 --- a/include/libcamera/internal/pipeline_handler.h +++ b/include/libcamera/internal/pipeline_handler.h @@ -14,7 +14,6 @@ #include #include -#include #include #include @@ -99,9 +98,7 @@ private: std::queue waitingRequests_; const char *name_; - - Mutex lock_; - unsigned int useCount_ LIBCAMERA_TSA_GUARDED_BY(lock_); + unsigned int useCount_; friend class PipelineHandlerFactoryBase; }; diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp index 4e393f89..61925e83 100644 --- a/src/libcamera/camera.cpp +++ b/src/libcamera/camera.cpp @@ -995,7 +995,8 @@ int Camera::acquire() if (ret < 0) return ret == -EACCES ? -EBUSY : ret; - if (!d->pipe_->acquire(this)) { + if (!d->pipe_->invokeMethod(&PipelineHandler::acquire, + ConnectionTypeBlocking, this)) { LOG(Camera, Info) << "Pipeline handler in use by another process"; return -EBUSY; @@ -1030,7 +1031,8 @@ int Camera::release() return ret == -EACCES ? -EBUSY : ret; if (d->isAcquired()) - d->pipe_->release(this); + d->pipe_->invokeMethod(&PipelineHandler::release, + ConnectionTypeBlocking, this); d->setState(Private::CameraAvailable); diff --git a/src/libcamera/pipeline_handler.cpp b/src/libcamera/pipeline_handler.cpp index 861815cb..b18b6d0b 100644 --- a/src/libcamera/pipeline_handler.cpp +++ b/src/libcamera/pipeline_handler.cpp @@ -157,7 +157,7 @@ MediaDevice *PipelineHandler::acquireMediaDevice(DeviceEnumerator *enumerator, * Pipeline handlers shall not call this function directly as the Camera class * handles access internally. * - * \context This function is \threadsafe. + * \context This function is called from the CameraManager thread. * * \return True if the pipeline handler was acquired, false if another process * has already acquired it @@ -165,8 +165,6 @@ MediaDevice *PipelineHandler::acquireMediaDevice(DeviceEnumerator *enumerator, */ bool PipelineHandler::acquire(Camera *camera) { - MutexLocker locker(lock_); - if (useCount_ == 0) { for (std::shared_ptr &media : mediaDevices_) { if (!media->lock()) { @@ -199,14 +197,12 @@ bool PipelineHandler::acquire(Camera *camera) * Pipeline handlers shall not call this function directly as the Camera class * handles access internally. * - * \context This function is \threadsafe. + * \context This function is called from the CameraManager thread. * * \sa acquire() */ void PipelineHandler::release(Camera *camera) { - MutexLocker locker(lock_); - ASSERT(useCount_); releaseDevice(camera); @@ -230,6 +226,8 @@ void PipelineHandler::release(Camera *camera) * powers on the USB device as soon as /dev/video# is opened. This behavior * should *not* be copied by other pipeline handlers. * + * \context This function is called from the CameraManager thread. + * * \return True on success, false on failure * \sa releaseDevice() */ @@ -250,6 +248,8 @@ bool PipelineHandler::acquireDevice([[maybe_unused]] Camera *camera) * release them until releaseDevice() has been called for all previously * acquired cameras. * + * \context This function is called from the CameraManager thread. + * * \sa acquireDevice() */ void PipelineHandler::releaseDevice([[maybe_unused]] Camera *camera)