From patchwork Fri Mar 14 10:31:13 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luca Ceresoli X-Patchwork-Id: 14016628 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 AD116C282EC for ; Fri, 14 Mar 2025 10:33:32 +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:Cc:To: Content-Transfer-Encoding:Content-Type:MIME-Version:Message-Id:Date:Subject: From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; 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t=1741948294; 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; bh=yEpZ4juRT6fBQZCKbXYpQBMIgNr/IaPoGPb+iKoyN+0=; b=FZ1oz6ZJsLewFtIdk4nCngYSG2+5EYWvhjJqyQfghuW7BeHzHc8uCudW8yTbDISu0ZadgA WGx8ZuM1LNfHJUODHwoqKB2jjwlpDiDzvm7aXT1vqK9Dfhq8461JWNG9+ppm8xA7yyerZ8 +e7Uj1i3s+LStsWWjUQbGEZ5W1Q2aFXaQdK2d56rPTwEEydTtZ90PzZayYL/Nszxp847oG zqZsoL6sr/fgNa1jZIE4t1rfWg+8+DHy9QdaDp0kbulKPTnVWDqolVf/r1jSyjvgeWsV7B v+lsG7N3ktEu1PI0FL07j6D343uTXU3VEOnS1Dz/X/hA6i/FfVXeTubtmybGsA== From: Luca Ceresoli Subject: [PATCH v7 00/11] drm/bridge: add devm_drm_bridge_alloc() with bridge refcount Date: Fri, 14 Mar 2025 11:31:13 +0100 Message-Id: <20250314-drm-bridge-refcount-v7-0-152571f8c694@bootlin.com> MIME-Version: 1.0 X-B4-Tracking: v=1; b=H4sIAHEF1GcC/6tWKk4tykwtVrJSqFYqSi3LLM7MzwNyzHUUlJIzE vPSU3UzU4B8JSMDI1MDY0MT3ZSiXN2koswUoExRalpyfmleia6pRYolUBaI0syUgDoLgDKZFWB To2NrawGhZXyjZQAAAA== X-Change-ID: 20250314-drm-bridge-refcount-58d9503503f6 To: Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Marek Vasut , Stefan Agner , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , Inki Dae , Jagan Teki , Marek Szyprowski Cc: Thomas Petazzoni , Anusha Srivatsa , Paul Kocialkowski , Dmitry Baryshkov , =?utf-8?q?Herv=C3=A9_Codina?= , Hui Pu , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, Luca Ceresoli X-Mailer: b4 0.14.2 X-GND-State: clean X-GND-Score: -100 X-GND-Cause: gggruggvucftvghtrhhoucdtuddrgeefvddrtddtgddufedtiedtucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuifetpfffkfdpucggtfgfnhhsuhgsshgtrhhisggvnecuuegrihhlohhuthemuceftddunecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjughrpefhufffkfggtgfgvfevofesthejredtredtjeenucfhrhhomhepnfhutggrucevvghrvghsohhlihcuoehluhgtrgdrtggvrhgvshholhhisegsohhothhlihhnrdgtohhmqeenucggtffrrghtthgvrhhnpefgieetkeekgfdtudevueffueffveekheeiudfhfedvhfeukeeuhffhtddtvdekfeenucffohhmrghinhepkhgvrhhnvghlrdhorhhgnecukfhppedvrgdtvdemieejtdemvddtvddtmegvrgdtudemrgdttddvmedusggrjeemgeekfhejmedulegtheenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepihhnvghtpedvrgdtvdemieejtdemvddtvddtmegvrgdtudemrgdttddvmedusggrjeemgeekfhejmedulegthedphhgvlhhopegludelvddrudeikedrudejkedruddukegnpdhmrghilhhfrhhomheplhhutggrrdgtvghrvghsohhlihessghoohhtlhhinhdrtghomhdpnhgspghrtghpthhtohepfedupdhrtghpthhtohepjfhuihdrrfhusehgvghhvggrlhhthhgtrghrvgdrtghomhdprhgtphhtthhopehinhhkihdruggrvgesshgrmhhsuhhnghdrtghomhdprhgtphhtthhopehmrghrvgigseguv ghngidruggvpdhrtghpthhtohepjhgvrhhnvghjrdhskhhrrggsvggtsehgmhgrihhlrdgtohhmpdhrtghpthhtohepphgruhhlkhesshihshdqsggrshgvrdhiohdprhgtphhtthhopegrshhrihhvrghtshesrhgvughhrghtrdgtohhmpdhrtghpthhtohepmhhrihhprghrugeskhgvrhhnvghlrdhorhhgpdhrtghpthhtohepjhhonhgrsheskhifihgsohhordhsvg X-GND-Sasl: luca.ceresoli@bootlin.com X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250314_033138_360824_26BD6A97 X-CRM114-Status: GOOD ( 11.76 ) 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 This series improves the way DRM bridges are allocated and initialized and makes them reference-counted. The goal of reference counting is to avoid use-after-free by drivers which got a pointer to a bridge and keep it stored and used even after the bridge has been deallocated. The overall goal is supporting Linux devices with a DRM pipeline whose final components can be hot-plugged and hot-unplugged, including one or more bridges. For more details see the big picture [0]. DRM bridge drivers will have to be adapted to the new API, which is pretty simple for most cases. Refcounting will have to be adopted on the two sides: all functions returning a bridge pointer and all code obtaining such a pointer. This series has just an overview of some of those conversions, because for now the main goal is to agree on the API. Series layout: 1. Add the new API and refcounting: drm/bridge: add devm_drm_bridge_alloc() drm/bridge: add support for refcounting 2. get/put the reference in basic operations in the bridge core: drm/bridge: get/put the bridge reference in drm_bridge_add/remove() drm/bridge: get/put the bridge reference in drm_bridge_attach/detach() 3. as an example of changes for bridge consumers, get a reference for the bridge returned by drm_bridge_chain_get_first_bridge(), have it put by all callers (all users will be covered later on separately): drm/bridge: add a cleanup action for scope-based drm_bridge_put() invocation drm/bridge: get the bridge returned by drm_bridge_chain_get_first_bridge() drm/mxsfb: put the bridge returned by drm_bridge_chain_get_first_bridge() drm/atomic-helper: put the bridge returned by drm_bridge_chain_get_first_bridge() drm/probe-helper: put the bridge returned by drm_bridge_chain_get_first_bridge() 4. convert a few bridge drivers (bridge providers) to the new API: drm/bridge: ti-sn65dsi83: use dynamic lifetime management drm/bridge: samsung-dsim: use dynamic lifetime management This work was formerly a part of my v6 DRM bridge hotplug series[0], now split as a standalone series with many improvements, hence the "v7" version number. [0] https://lore.kernel.org/dri-devel/20250206-hotplug-drm-bridge-v6-0-9d6f2c9c3058@bootlin.com/ Signed-off-by: Luca Ceresoli --- Luca Ceresoli (11): drm/bridge: add devm_drm_bridge_alloc() drm/bridge: add support for refcounting drm/bridge: get/put the bridge reference in drm_bridge_add/remove() drm/bridge: get/put the bridge reference in drm_bridge_attach/detach() drm/bridge: add a cleanup action for scope-based drm_bridge_put() invocation drm/bridge: get the bridge returned by drm_bridge_chain_get_first_bridge() drm/mxsfb: put the bridge returned by drm_bridge_chain_get_first_bridge() drm/atomic-helper: put the bridge returned by drm_bridge_chain_get_first_bridge() drm/probe-helper: put the bridge returned by drm_bridge_chain_get_first_bridge() drm/bridge: ti-sn65dsi83: use dynamic lifetime management drm/bridge: samsung-dsim: use dynamic lifetime management drivers/gpu/drm/bridge/samsung-dsim.c | 7 +- drivers/gpu/drm/bridge/ti-sn65dsi83.c | 7 +- drivers/gpu/drm/drm_atomic_helper.c | 5 ++ drivers/gpu/drm/drm_bridge.c | 74 +++++++++++++++++++-- drivers/gpu/drm/drm_probe_helper.c | 1 + drivers/gpu/drm/mxsfb/lcdif_kms.c | 3 +- include/drm/drm_bridge.h | 119 +++++++++++++++++++++++++++++++++- 7 files changed, 201 insertions(+), 15 deletions(-) --- base-commit: 9e6d91c60b0d64a4f945663993b3bbf4f3fb7392 change-id: 20250314-drm-bridge-refcount-58d9503503f6 Best regards,