From nobody Wed Dec 17 19:16:26 2025 Received: from smtpout-02.galae.net (smtpout-02.galae.net [185.246.84.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 525962EB5C4 for ; Fri, 3 Oct 2025 10:39:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.246.84.56 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759487989; cv=none; b=VIxfwZjkjL/bgMzPzV9kpC4vnJM8ZsX5nIRPUpTRWc2RwOiCoMTM1wV0Xd1d+kNjBWx+mRXFfB8Lq6XzYjXoNOFP9GTOjettlMkgLHiTs4/gSJqd1ljT4DY5hswbQfeUXXJ5AlcZR9Gijsx+Jfq0LbtJYOzLtEEMmWLn4Nv2uCU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759487989; c=relaxed/simple; bh=sgR/vk9NFVTq9/RGQC8Ws+41fPZiEQ+J5+Vd7L06AeU=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=TofrC5QHCh1Isa71SAzCJXpaNt/wfsO2ZSUoul+21p3x+kt5Yil6601Fijrt0PyOT5zUZVvX5QQRQ73/m1IclKI2khTg8tpS8tDRfGF7D/JIw/ZTc2S/hvmXrm5Tq3v7ili5OYyGvx71lQSoxxIkq/XAP9/uS3zKqqnRGGXm0Hs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=TavQ+tKW; arc=none smtp.client-ip=185.246.84.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="TavQ+tKW" Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-02.galae.net (Postfix) with ESMTPS id B81071A10C7; Fri, 3 Oct 2025 10:39:45 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id 87D9160683; Fri, 3 Oct 2025 10:39:45 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 44522102F1C34; Fri, 3 Oct 2025 12:39:43 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1759487984; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=i5fUEUgIVWMunz1YPOYTWYL3LVH7gS/tsB8DL80Sfco=; b=TavQ+tKW/HRQ5PLxtRACT02jNmQLru465Io0wcsbv+cPYz6k/sFZUzp6HlYCS+RETRuqTl p+mC5LXxgAB6pPEEKBB1pg9kLsaEmrnNpDQ3jRsxenZ+7CMyJn3lBjWYle/qdjd+dl2gGF bFHUQZuajWIi1KTBuvk0J/j9HMAuPOBHV+4WjLp24x1pAeTWqLAFMk04RKQ8nSfS8NNf2o H1XX8UKGEpT6+XPnMoWS3eOoRzoLhcjdWc3RJK8DudQnJ4i3duha3dkRn8TgVFpvbrqQRX 4dP0OMpgDaPTOVVizDgSvuJGYGg75oOHibkKay+1nayWwWSStQPcj6G2wDrzhA== From: Luca Ceresoli Date: Fri, 03 Oct 2025 12:39:25 +0200 Subject: [PATCH v2 3/7] drm/bridge: lock the encoder bridge chain mutex during insertion Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20251003-drm-bridge-alloc-encoder-chain-mutex-v2-3-78bf61580a06@bootlin.com> References: <20251003-drm-bridge-alloc-encoder-chain-mutex-v2-0-78bf61580a06@bootlin.com> In-Reply-To: <20251003-drm-bridge-alloc-encoder-chain-mutex-v2-0-78bf61580a06@bootlin.com> To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec Cc: Hui Pu , Thomas Petazzoni , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Luca Ceresoli X-Mailer: b4 0.14.2 X-Last-TLS-Session-Version: TLSv1.3 drm_bridge_attach() modifies the encoder bridge chain, so take a mutex around such operations to allow users of the chain to protect themselves from chain modifications while iterating. Signed-off-by: Luca Ceresoli --- Changes in v2: - Removed comment before on drm_bridge_detach() --- drivers/gpu/drm/drm_bridge.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index 53e7ece36dd940aabd1c0880f296fce7224a12ac..d2ab7cef0b768b0ff674a779778= 33da27133912f 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -453,10 +453,12 @@ int drm_bridge_attach(struct drm_encoder *encoder, st= ruct drm_bridge *bridge, bridge->dev =3D encoder->dev; bridge->encoder =3D encoder; =20 + drm_encoder_chain_lock(encoder); if (previous) list_add(&bridge->chain_node, &previous->chain_node); else list_add(&bridge->chain_node, &encoder->bridge_chain); + drm_encoder_chain_unlock(encoder); =20 if (bridge->funcs->attach) { ret =3D bridge->funcs->attach(bridge, encoder, flags); @@ -487,7 +489,9 @@ int drm_bridge_attach(struct drm_encoder *encoder, stru= ct drm_bridge *bridge, err_reset_bridge: bridge->dev =3D NULL; bridge->encoder =3D NULL; + drm_encoder_chain_lock(encoder); list_del(&bridge->chain_node); + drm_encoder_chain_unlock(encoder); =20 if (ret !=3D -EPROBE_DEFER) DRM_ERROR("failed to attach bridge %pOF to encoder %s: %d\n", --=20 2.51.0