From patchwork Mon Sep 11 14:05:30 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michael Grzeschik X-Patchwork-Id: 13379815 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0E41DCA0EC5 for ; Mon, 11 Sep 2023 21:06:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229700AbjIKUrA (ORCPT ); Mon, 11 Sep 2023 16:47:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42974 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238827AbjIKOFs (ORCPT ); Mon, 11 Sep 2023 10:05:48 -0400 Received: from metis.whiteo.stw.pengutronix.de (metis.whiteo.stw.pengutronix.de [IPv6:2a0a:edc0:2:b01:1d::104]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D8747CF0 for ; Mon, 11 Sep 2023 07:05:43 -0700 (PDT) Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.whiteo.stw.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1qfhXq-0006np-AR; Mon, 11 Sep 2023 16:05:42 +0200 Received: from [2a0a:edc0:0:1101:1d::ac] (helo=dude04.red.stw.pengutronix.de) by drehscheibe.grey.stw.pengutronix.de with esmtp (Exim 4.94.2) (envelope-from ) id 1qfhXp-005ZV7-T7; Mon, 11 Sep 2023 16:05:41 +0200 Received: from mgr by dude04.red.stw.pengutronix.de with local (Exim 4.96) (envelope-from ) id 1qfhXp-002tVj-0x; Mon, 11 Sep 2023 16:05:41 +0200 From: Michael Grzeschik To: laurent.pinchart@ideasonboard.com Cc: linux-usb@vger.kernel.org, linux-media@vger.kernel.org, dan.scally@ideasonboard.com, gregkh@linuxfoundation.org, nicolas@ndufresne.ca, kernel@pengutronix.de Subject: [PATCH v2 3/3] usb: gadget: uvc: rework pump worker to avoid while loop Date: Mon, 11 Sep 2023 16:05:30 +0200 Message-Id: <20230911140530.2995138-4-m.grzeschik@pengutronix.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230911140530.2995138-1-m.grzeschik@pengutronix.de> References: <20230911140530.2995138-1-m.grzeschik@pengutronix.de> MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: mgr@pengutronix.de X-SA-Exim-Scanned: No (on metis.whiteo.stw.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-media@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org The uvc_video_enable function is calling cancel_work_sync which will be blocking as long as new requests will be queued with the while loop. To ensure an earlier stop in the pumping loop in this particular case we rework the worker to requeue itself on every requests. Since the worker is already running prioritized, the scheduling overhad did not have real impact on the performance. Signed-off-by: Michael Grzeschik --- v1 == v2 drivers/usb/gadget/function/uvc_video.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/drivers/usb/gadget/function/uvc_video.c b/drivers/usb/gadget/function/uvc_video.c index c48c904f500fff..97d875c27dcf9a 100644 --- a/drivers/usb/gadget/function/uvc_video.c +++ b/drivers/usb/gadget/function/uvc_video.c @@ -397,7 +397,7 @@ static void uvcg_video_pump(struct work_struct *work) bool buf_done; int ret; - while (video->ep->enabled && uvc->state == UVC_STATE_STREAMING) { + if (video->ep->enabled && uvc->state == UVC_STATE_STREAMING) { /* * Retrieve the first available USB request, protected by the * request lock. @@ -409,6 +409,11 @@ static void uvcg_video_pump(struct work_struct *work) } req = list_first_entry(&video->req_free, struct usb_request, list); + if (!req) { + spin_unlock_irqrestore(&video->req_lock, flags); + return; + } + list_del(&req->list); spin_unlock_irqrestore(&video->req_lock, flags); @@ -437,7 +442,7 @@ static void uvcg_video_pump(struct work_struct *work) * further. */ spin_unlock_irqrestore(&queue->irqlock, flags); - break; + goto out; } /* @@ -470,20 +475,23 @@ static void uvcg_video_pump(struct work_struct *work) /* Queue the USB request */ ret = uvcg_video_ep_queue(video, req); spin_unlock_irqrestore(&queue->irqlock, flags); - if (ret < 0) { uvcg_queue_cancel(queue, 0); - break; + goto out; } /* Endpoint now owns the request */ req = NULL; video->req_int_count++; + } else { + return; } - if (!req) - return; + if (uvc->state == UVC_STATE_STREAMING) + queue_work(video->async_wq, &video->pump); + return; +out: spin_lock_irqsave(&video->req_lock, flags); list_add_tail(&req->list, &video->req_free); spin_unlock_irqrestore(&video->req_lock, flags);