From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 C2A441741E0 for ; Mon, 7 Oct 2024 09:27:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728293235; cv=none; b=MZ1LdfkqCRd4BBSw/E6TvHji1zFYjSSgGB+uHfwGDvtkO99CFrpKeSFxTx917Un0Ec/E3o2PLe00QZhiVE/KpFkbfs3EB9WaS8tu72X6LQRFsoIJCngVSvfLuPKs9OfaLTxxlteKZjpKV2QZ4L4M6zqH40a5Y2eztpBv/WScV3c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728293235; c=relaxed/simple; bh=A+RPNifFqXmtQsdEdXdUWwI5tkU0NZG+Sggv80gvsdk=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=mTeYqcWAnOX+0qoVdyMn8V3o5seh26wW+V+dipuux+iKRhaj3NRSx8/5ktrfRENP61miF/5bd4STbnFxASJBH43qdEOZjP0vu28ow9c/rsDP54nweUUBZ4/DVHIUiU0B40Dk41PiOVHqXxjE0DU9TnJeWaijzd6wM0AvT0vLdtI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=fvc70dH8; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="fvc70dH8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 00D06C4CEC6; Mon, 7 Oct 2024 09:27:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1728293235; bh=A+RPNifFqXmtQsdEdXdUWwI5tkU0NZG+Sggv80gvsdk=; h=Subject:To:Cc:From:Date:From; b=fvc70dH8/yxwrcgHimg6ehNBcbErumamBiS8kK01P18Dx+c/kB4mqEYENxkHjZigo 2Np6FX6LMze2pAlrRTm4lRBCfiq0xWBYAa+KuNnwiNX3BbSyDrymuFFSWahyefT+X4 c0bMN7KCKgcjfTpBDGv027jzmh8xgDIPx83BpZHk= Subject: FAILED: patch "[PATCH] i2c: core: Lock address during client device instantiation" failed to apply to 6.6-stable tree To: hkallweit1@gmail.com,ole@ans.pl,wsa+renesas@sang-engineering.com Cc: From: Date: Mon, 07 Oct 2024 11:27:12 +0200 Message-ID: <2024100712-pranker-disband-ee25@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 8d3cefaf659265aa82b0373a563fdb9d16a2b947 # git commit -s git send-email --to '' --in-reply-to '2024100712-pranker-disband-ee25@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: 8d3cefaf6592 ("i2c: core: Lock address during client device instantiation") 73febd775bdb ("i2c: create debugfs entry per adapter") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 8d3cefaf659265aa82b0373a563fdb9d16a2b947 Mon Sep 17 00:00:00 2001 From: Heiner Kallweit Date: Thu, 15 Aug 2024 21:44:50 +0200 Subject: [PATCH] i2c: core: Lock address during client device instantiation Krzysztof reported an issue [0] which is caused by parallel attempts to instantiate the same I2C client device. This can happen if driver supports auto-detection, but certain devices are also instantiated explicitly. The original change isn't actually wrong, it just revealed that I2C core isn't prepared yet to handle this scenario. Calls to i2c_new_client_device() can be nested, therefore we can't use a simple mutex here. Parallel instantiation of devices at different addresses is ok, so we just have to prevent parallel instantiation at the same address. We can use a bitmap with one bit per 7-bit I2C client address, and atomic bit operations to set/check/clear bits. Now a parallel attempt to instantiate a device at the same address will result in -EBUSY being returned, avoiding the "sysfs: cannot create duplicate filename" splash. Note: This patch version includes small cosmetic changes to the Tested-by version, only functional change is that address locking is supported for slave addresses too. [0] https://lore.kernel.org/linux-i2c/9479fe4e-eb0c-407e-84c0-bd60c15baf74@ans.pl/T/#m12706546e8e2414d8f1a0dc61c53393f731685cc Fixes: caba40ec3531 ("eeprom: at24: Probe for DDR3 thermal sensor in the SPD case") Cc: stable@vger.kernel.org Tested-by: Krzysztof Piotr Oledzki Signed-off-by: Heiner Kallweit Signed-off-by: Wolfram Sang diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c index b63f75e44296..e39e8d792d03 100644 --- a/drivers/i2c/i2c-core-base.c +++ b/drivers/i2c/i2c-core-base.c @@ -915,6 +915,27 @@ int i2c_dev_irq_from_resources(const struct resource *resources, return 0; } +/* + * Serialize device instantiation in case it can be instantiated explicitly + * and by auto-detection + */ +static int i2c_lock_addr(struct i2c_adapter *adap, unsigned short addr, + unsigned short flags) +{ + if (!(flags & I2C_CLIENT_TEN) && + test_and_set_bit(addr, adap->addrs_in_instantiation)) + return -EBUSY; + + return 0; +} + +static void i2c_unlock_addr(struct i2c_adapter *adap, unsigned short addr, + unsigned short flags) +{ + if (!(flags & I2C_CLIENT_TEN)) + clear_bit(addr, adap->addrs_in_instantiation); +} + /** * i2c_new_client_device - instantiate an i2c device * @adap: the adapter managing the device @@ -962,6 +983,10 @@ i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *inf goto out_err_silent; } + status = i2c_lock_addr(adap, client->addr, client->flags); + if (status) + goto out_err_silent; + /* Check for address business */ status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client)); if (status) @@ -993,6 +1018,8 @@ i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *inf dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n", client->name, dev_name(&client->dev)); + i2c_unlock_addr(adap, client->addr, client->flags); + return client; out_remove_swnode: @@ -1004,6 +1031,7 @@ i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *inf dev_err(&adap->dev, "Failed to register i2c client %s at 0x%02x (%d)\n", client->name, client->addr, status); + i2c_unlock_addr(adap, client->addr, client->flags); out_err_silent: if (need_put) put_device(&client->dev); diff --git a/include/linux/i2c.h b/include/linux/i2c.h index 7eedd0c662da..8d79440cd8ce 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -761,6 +761,9 @@ struct i2c_adapter { struct regulator *bus_regulator; struct dentry *debugfs; + + /* 7bit address space */ + DECLARE_BITMAP(addrs_in_instantiation, 1 << 7); }; #define to_i2c_adapter(d) container_of(d, struct i2c_adapter, dev)