From mboxrd@z Thu Jan 1 00:00:00 1970 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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 2FDA9CD8CB9 for ; Wed, 10 Jun 2026 13:30:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:References: Subject:From:To:Cc:Message-Id:Date:Content-Type:Content-Transfer-Encoding: Mime-Version:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=shrZ7CpTKyIgEFXVs/ZXsWjGHpF8pSdJAOdanCrWqrg=; b=2drCG9l7/VzFMISXSojHlzIqTk 2/smNyXAZbXP0fK6iU+CJWzmBMO77vTAdOkrA4IDZD+v2vrG1gQNcKeFy/urBAfGlv82R2Wm5OC95 9+6UynakmqalumaBmFHIAEl88scdOrtHpem2eAzZrndWqmALOWQ7RWy4FFm42ZrR5eBCCUXiLPFU3 n4uH6F36F+AhxXfd/nCohPoIBaw4xQlPJjr0oAUC4qrmq8KZ8mTYANCxKpL4b0ONHZISky/Ye/mhV Hn4a+X81IkOvuLfoKLjCuQKJMaOCCX5iw7BJ1Yv5c+PV//GSpr6+Fql3alc+Bq618qSi20bzZdABx eoL59IwQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wXJ0j-00000007mUs-2XZX; Wed, 10 Jun 2026 13:30:25 +0000 Received: from smtpout-03.galae.net ([185.246.85.4]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wXJ0g-00000007mUK-1SdR for linux-arm-kernel@lists.infradead.org; Wed, 10 Jun 2026 13:30:24 +0000 Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-03.galae.net (Postfix) with ESMTPS id 181C84E42DFB; Wed, 10 Jun 2026 13:30:20 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id DC5A65FFC9; Wed, 10 Jun 2026 13:30:19 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 69C2A106B82D9; Wed, 10 Jun 2026 15:30:11 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1781098218; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=shrZ7CpTKyIgEFXVs/ZXsWjGHpF8pSdJAOdanCrWqrg=; b=RpL3FUhPUcKqrnMh5NSyakg6RJXeX2sWTGp1hyfNIQYIEfnK6eyJbhv448ghySEjepxq8J JYrNz5epUEzxjS2cLc4hdYPhBVjfngOPS0+pFuqKPn0kQejY+G3j5dzI+06FkZaFMddDg7 lndOEhaZkCidVj9Dip0DQiIlblX5NHGUQTvGTC4f3N0cxvrVCyUJfeYemclTa2hSrGRsUZ Gx5yWMSQKwsjfdMBnPh96uo4TCAP7yr2neSIwdBGg9O92IO019jRRQMRBp7Y519+92QaDa 7n2/BQFsQpUw+yBiuj2mV6XVQUUpCem8KHzXzYL5S3cjz3Fu8O5MkVh3/EscWQ== Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Wed, 10 Jun 2026 15:30:10 +0200 Message-Id: Cc: "Maarten Lankhorst" , "Thomas Zimmermann" , "David Airlie" , "Simona Vetter" , "Andrzej Hajda" , "Neil Armstrong" , "Robert Foss" , "Laurent Pinchart" , "Jonas Karlman" , "Jernej Skrabec" , "Inki Dae" , "Jagan Teki" , "Marek Szyprowski" , "Marek Vasut" , "Stefan Agner" , "Frank Li" , "Sascha Hauer" , "Pengutronix Kernel Team" , "Fabio Estevam" , "Hui Pu" , "Ian Ray" , "Thomas Petazzoni" , , , , To: "Maxime Ripard" , "Luca Ceresoli" From: "Luca Ceresoli" Subject: Re: [PATCH 17/37] drm/display: bridge-connector: protect dynconn creation and destruction with a mutex X-Mailer: aerc 0.21.0 References: <20260519-drm-bridge-hotplug-v1-0-45e2bdb3dfb4@bootlin.com> <20260519-drm-bridge-hotplug-v1-17-45e2bdb3dfb4@bootlin.com> <20260608-garrulous-silver-junglefowl-ea4dbe@houat> In-Reply-To: <20260608-garrulous-silver-junglefowl-ea4dbe@houat> X-Last-TLS-Session-Version: TLSv1.3 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260610_063022_531187_2247DFC9 X-CRM114-Status: GOOD ( 11.57 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon Jun 8, 2026 at 1:49 PM CEST, Maxime Ripard wrote: > On Tue, May 19, 2026 at 12:37:34PM +0200, Luca Ceresoli wrote: >> Bridge hotplug will make the connector dynamically created and destroyed >> based on hotplug events. >> >> In preparation for that, add a mutex to mutually exclude connector creat= ion >> and destruction. >> >> Signed-off-by: Luca Ceresoli > > What is the source of concurrency, and what are you protecting against > exactly with that lock? With bridge hotplug, the connector creation and destruction can be triggered by different code paths, so we need to prevent to: * start destroying a connector that has not been created fully yet * start creating a connector while the previous one is still being destroyed Both conditions might happen startig with patch 36. So I guess I'll just squash this patch into patch 36. The commit message will become quite verbose but it amkes sense to do it all at once. Luca -- Luca Ceresoli, Bootlin Embedded Linux and Kernel engineering https://bootlin.com