From patchwork Wed Mar 25 21:34:32 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ezequiel Garcia X-Patchwork-Id: 11458673 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 916C692A for ; Wed, 25 Mar 2020 21:35:08 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 705F62070A for ; Wed, 25 Mar 2020 21:35:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="I5GXK0VN" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 705F62070A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=collabora.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-rockchip-bounces+patchwork-linux-rockchip=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=2D1JduLDO5muRl94t+9ODKTkHLCQvtWXHvgzc+XOfPM=; b=I5GXK0VNGN73wh R3kPHaPvJRgokoRkSMYHxj6XhPLVmKav53K/t7T/gWDdentqkWg7poFWKmvwb3Jg3IS/OO3gaCa2M BJENnF0koqOSrINIAzqcGcAe9MA1XB0rN9tI18hO2O8Z6mSSJr8lHpdX8i7wntRKox6qoAmXQjVru NSh/qPkV4fLshOajrnWWuFIgUcB43gWwB+8RddTdfpr72YQYzgx2Lmj2OrrT8xXc/xUY1X8q8ju5w +gfjzS/aBt0J1DHNfHzZ3F99+Xoq2ulRMziW4/drpfmcPZvKNKywNdYRROXnBhe2zuTOMn6YQm5QU HW64H38TLb3FpaWx68xQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jHDg0-0006gJ-MH; Wed, 25 Mar 2020 21:35:04 +0000 Received: from bhuna.collabora.co.uk ([2a00:1098:0:82:1000:25:2eeb:e3e3]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jHDfx-0006Lz-GH for linux-rockchip@lists.infradead.org; Wed, 25 Mar 2020 21:35:03 +0000 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: ezequiel) with ESMTPSA id 63A5B293EA9 From: Ezequiel Garcia To: linux-media@vger.kernel.org, linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 1/7] v4l2-mem2mem: return CAPTURE buffer first Date: Wed, 25 Mar 2020 18:34:32 -0300 Message-Id: <20200325213439.16509-2-ezequiel@collabora.com> X-Mailer: git-send-email 2.26.0.rc2 In-Reply-To: <20200325213439.16509-1-ezequiel@collabora.com> References: <20200325213439.16509-1-ezequiel@collabora.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200325_143501_671937_D0D0A034 X-CRM114-Status: UNSURE ( 9.58 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -0.0 (/) X-Spam-Report: SpamAssassin version 3.4.4 on bombadil.infradead.org summary: Content analysis details: (-0.0 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 SPF_PASS SPF: sender matches SPF record -0.0 SPF_HELO_PASS SPF: HELO matches SPF record 0.0 UNPARSEABLE_RELAY Informational: message has unparseable relay lines X-BeenThere: linux-rockchip@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Upstream kernel work for Rockchip platforms List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Rob Herring , Tomasz Figa , Heiko Stuebner , Alexandre Courbot , Jonas Karlman , Nicolas Dufresne , Hans Verkuil , devicetree@vger.kernel.org, Jeffrey Kardatzke , Nicolas Dufresne , kernel@collabora.com, Ezequiel Garcia Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+patchwork-linux-rockchip=patchwork.kernel.org@lists.infradead.org When the request API is used, typically an OUTPUT (src) buffer will be part of a request. A userspace process will be typically blocked, waiting on the request file descriptor. Returning the OUTPUT (src) buffer will wake-up such processes, who will immediately attempt to dequeue the CAPTURE buffer, only to find it's still unavailable. Therefore, change v4l2_m2m_buf_done_and_job_finish returning the CAPTURE (dst) buffer first, to avoid signalling the request file descriptor prematurely, i.e. before the CAPTURE buffer is done. When the request API is not used, this change should have no impact. Tested-by: Nicolas Dufresne Signed-off-by: Ezequiel Garcia --- drivers/media/v4l2-core/v4l2-mem2mem.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/media/v4l2-core/v4l2-mem2mem.c b/drivers/media/v4l2-core/v4l2-mem2mem.c index 8986c31176e9..62ac9424c92a 100644 --- a/drivers/media/v4l2-core/v4l2-mem2mem.c +++ b/drivers/media/v4l2-core/v4l2-mem2mem.c @@ -504,12 +504,21 @@ void v4l2_m2m_buf_done_and_job_finish(struct v4l2_m2m_dev *m2m_dev, if (WARN_ON(!src_buf || !dst_buf)) goto unlock; - v4l2_m2m_buf_done(src_buf, state); dst_buf->is_held = src_buf->flags & V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF; if (!dst_buf->is_held) { v4l2_m2m_dst_buf_remove(m2m_ctx); v4l2_m2m_buf_done(dst_buf, state); } + /* + * If the request API is being used, returning the OUTPUT + * (src) buffer will wake-up any process waiting on the + * request file descriptor. + * + * Therefore, return the CAPTURE (dst) buffer first, + * to avoid signalling the request file descriptor + * before the CAPTURE buffer is done. + */ + v4l2_m2m_buf_done(src_buf, state); schedule_next = _v4l2_m2m_job_finish(m2m_dev, m2m_ctx); unlock: spin_unlock_irqrestore(&m2m_dev->job_spinlock, flags);