From patchwork Wed Jan 15 09:25:40 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Romain Gantois X-Patchwork-Id: 13940112 Received: from relay9-d.mail.gandi.net (relay9-d.mail.gandi.net [217.70.183.199]) (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 B755124819C; Wed, 15 Jan 2025 09:26:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.183.199 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736933171; cv=none; b=l5pu+FMG4CnTRpdlI/czqQjA4AWJ2R/+pI/Gb+2GVrnFQMZbiXJt8sOK0SV3wLU/OW3vTCK0Y/GxoDNsowiLMUKYWCp0mS4Ig4S1qVk32/HMiTkUQ4Ld62WiWsydXvY3X2oKncknp7TuSHtKreT/LnRJL6b/lAgOWXvTnGkvy2Q= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736933171; c=relaxed/simple; bh=ASQ6Fw5qjJ/O0iPC+m3DVBcrmxyvL2adNzVtUrBPFi0=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=WZj3V0HQyiuODyMeZsCF/yEcIQpxM8BVcIfvzJyBaYp1KSS9cuHIEpwf5kbuU2+Iw31I4TYKtpC+1u0fyqySQxyzScEUx6bJIHyHuVlsWDMufiuX4O3eOxVrzacEXdAQXZXLdHZGBKCj00aixKVeGDR1ZtGAbd8fWynnc3hx8l0= 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=AIBLcUZP; arc=none smtp.client-ip=217.70.183.199 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="AIBLcUZP" Received: by mail.gandi.net (Postfix) with ESMTPSA id 367B1FF80E; Wed, 15 Jan 2025 09:26:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1736933167; 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: in-reply-to:in-reply-to:references:references; bh=MOSmciKpV7p8jAIDgx8nyxSnPVuTNrLy1iE6XeNvccY=; b=AIBLcUZPJSPEnUMDAI9qnDicfpwFRAV6b1gctWIOmhwFrcKvxsUjRl7MS3ILBYszv4vNjO xFM5ZgBFf3sU1e7UZeNKf8FmupgAZQUtcudzUetUE/upmu8SMPWSrcUrqV9//GcaTnmNVF YVT+NSmSsTHnOl6Dum2toC3uUw0V3h2feyLefyGmZM3z3vggIeHENUX8BgYqNwzqZraVLd bcw+EGoWStIpcOJ5/EfllVwLy6It23ABjK2CyeYNhLlE1Kk+8fpPTZ8Fqb3kRcCa6PC9v5 m4xVh8HAyQApuZRkJrFXgIpW+HLg0SBkvp9GJptINBQjy7lwl6LwJck4AExRiA== From: Romain Gantois Date: Wed, 15 Jan 2025 10:25:40 +0100 Subject: [PATCH v6 3/9] media: i2c: ds90ub960: Protect alias_use_mask with a mutex Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250115-fpc202-v6-3-d47a34820753@bootlin.com> References: <20250115-fpc202-v6-0-d47a34820753@bootlin.com> In-Reply-To: <20250115-fpc202-v6-0-d47a34820753@bootlin.com> To: Wolfram Sang , Tomi Valkeinen , Luca Ceresoli , Andi Shyti , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Derek Kiernan , Dragan Cvetic , Arnd Bergmann , Greg Kroah-Hartman , Mauro Carvalho Chehab , Linus Walleij , Bartosz Golaszewski Cc: Thomas Petazzoni , Kory Maincent , linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-media@vger.kernel.org, linux-gpio@vger.kernel.org, Romain Gantois X-Mailer: b4 0.14.2 X-GND-Sasl: romain.gantois@bootlin.com The aliased_addrs list represents the occupation of an RX port's hardware alias table. This list and the underlying hardware table are only accessed in the attach/detach_client() callbacks. These functions are only called from a bus notifier handler in i2c-atr.c, which is always called with the notifier chain's semaphore held. This indirectly prevents concurrent access to the aliased_addrs list. However, more explicit and direct locking is preferable. Moreover, with the introduction of dynamic address translation in a future patch, the attach/detach_client() callbacks will be called from outside of the notifier chain's read section. Introduce a mutex to protect access to the aliased_addrs list and its underlying hardware table. Signed-off-by: Romain Gantois --- drivers/media/i2c/ds90ub960.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/media/i2c/ds90ub960.c b/drivers/media/i2c/ds90ub960.c index 13fb6020364d2b2d774400755f65da19365f220b..0c83c07c287c5eb168ec5d761f3d803c96d1e649 100644 --- a/drivers/media/i2c/ds90ub960.c +++ b/drivers/media/i2c/ds90ub960.c @@ -27,6 +27,7 @@ */ #include +#include #include #include #include @@ -467,6 +468,8 @@ struct ub960_rxport { }; } eq; + /* lock for aliased_addrs and associated registers */ + struct mutex aliased_addrs_lock; u16 aliased_addrs[UB960_MAX_PORT_ALIASES]; }; @@ -1031,6 +1034,8 @@ static int ub960_atr_attach_client(struct i2c_atr *atr, u32 chan_id, struct device *dev = &priv->client->dev; unsigned int reg_idx; + guard(mutex)(&rxport->aliased_addrs_lock); + for (reg_idx = 0; reg_idx < ARRAY_SIZE(rxport->aliased_addrs); reg_idx++) { if (!rxport->aliased_addrs[reg_idx]) break; @@ -1062,6 +1067,8 @@ static void ub960_atr_detach_client(struct i2c_atr *atr, u32 chan_id, struct device *dev = &priv->client->dev; unsigned int reg_idx; + guard(mutex)(&rxport->aliased_addrs_lock); + for (reg_idx = 0; reg_idx < ARRAY_SIZE(rxport->aliased_addrs); reg_idx++) { if (rxport->aliased_addrs[reg_idx] == client->addr) break; @@ -3181,6 +3188,8 @@ static void ub960_rxport_free_ports(struct ub960_data *priv) fwnode_handle_put(rxport->source.ep_fwnode); fwnode_handle_put(rxport->ser.fwnode); + mutex_destroy(&rxport->aliased_addrs_lock); + kfree(rxport); priv->rxports[nport] = NULL; } @@ -3401,6 +3410,8 @@ static int ub960_parse_dt_rxport(struct ub960_data *priv, unsigned int nport, if (ret) goto err_put_remote_fwnode; + mutex_init(&rxport->aliased_addrs_lock); + return 0; err_put_remote_fwnode: