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Tue, 28 May 2019 09:08:21 +0000 From: "Adamski, Krzysztof (Nokia - PL/Wroclaw)" To: Wolfram Sang CC: "linux-kernel@vger.kernel.org" , "linux-i2c@vger.kernel.org" Subject: [PATCH] hwmon: pmbus: protect read-modify-write with lock Thread-Topic: [PATCH] hwmon: pmbus: protect read-modify-write with lock Thread-Index: AQHVFTTlNgEhk1J/hUaHnYTTiQ8+FA== Date: Tue, 28 May 2019 09:08:21 +0000 Message-ID: <20190528090746.GA31184@localhost.localdomain> Accept-Language: pl-PL, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-clientproxiedby: HE1PR0701CA0079.eurprd07.prod.outlook.com (2603:10a6:3:64::23) To HE1PR07MB3337.eurprd07.prod.outlook.com (2603:10a6:7:2d::12) authentication-results: spf=none (sender IP is ) smtp.mailfrom=krzysztof.adamski@nokia.com; x-ms-exchange-messagesentrepresentingtype: 1 x-originating-ip: [131.228.32.164] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: f07689c8-a65b-4c00-e856-08d6e34c07d2 x-ms-office365-filtering-ht: Tenant x-microsoft-antispam: BCL:0; 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FPR:; SPF:None; LANG:en; PTR:InfoNoRecords; MX:1; A:1; received-spf: None (protection.outlook.com: nokia.com does not designate permitted sender hosts) x-ms-exchange-senderadcheck: 1 x-microsoft-antispam-message-info: rDC2uIWCk1dmLgwF9YFxDgKO0QktPlHOfHpKpiEQGCpgRQFnl8Vfw1MKpGfpthAgvwT87V1mqyk5x9CVHPS/yj6Ej9lOrkUG87x4ZLnx/asaHFE49nZ2/vB3x41freCEOf8nK44mUuZbQMskjNBVRdzZQ3t8xPToi+34tHBFsCOqhaVzPvO9qZ7DWCZtDt3UWHxL/SD2qYxmogmdBit58A94dwSCh+hWU0uMmLGWSdBMhQAgbYMLfLttFVXv51oANFIN58Xkd1h/qMnVmtVQ0uwKnLBcycMd1gRUoh2fbiV0ibI7iFI7VCfSVfkJxf+sv566HpnFhOj2z5OOLrzwZncZEpvh7xbRCU9OJ3PLpb2f4bwq4bS5wZzSNrqMEnDyJQ+QgrrpbVfDAnu7dj10UvCfcLwDXcN9cJnhu+51cck= Content-ID: <3E7B0680287AFA4E9AFE88ABE2A0BAC9@eurprd07.prod.outlook.com> MIME-Version: 1.0 X-OriginatorOrg: nokia.com X-MS-Exchange-CrossTenant-Network-Message-Id: f07689c8-a65b-4c00-e856-08d6e34c07d2 X-MS-Exchange-CrossTenant-originalarrivaltime: 28 May 2019 09:08:21.3182 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 5d471751-9675-428d-917b-70f44f9630b0 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: krzysztof.adamski@nokia.com X-MS-Exchange-Transport-CrossTenantHeadersStamped: HE1PR07MB4250 Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org The operation done in the pmbus_update_fan() function is a read-modify-write operation but it lacks any kind of lock protection which may cause problems if run more than once simultaneously. This patch uses an existing update_lock mutex to fix this problem. Signed-off-by: Krzysztof Adamski --- drivers/hwmon/pmbus/pmbus_core.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c index ef7ee90ee785..94adbede7912 100644 --- a/drivers/hwmon/pmbus/pmbus_core.c +++ b/drivers/hwmon/pmbus/pmbus_core.c @@ -268,6 +268,7 @@ int pmbus_update_fan(struct i2c_client *client, int page, int id, int rv; u8 to; + mutex_lock(&data->update_lock); from = pmbus_read_byte_data(client, page, pmbus_fan_config_registers[id]); if (from < 0) @@ -278,11 +279,15 @@ int pmbus_update_fan(struct i2c_client *client, int page, int id, rv = pmbus_write_byte_data(client, page, pmbus_fan_config_registers[id], to); if (rv < 0) - return rv; + goto out; } - return _pmbus_write_word_data(client, page, - pmbus_fan_command_registers[id], command); + rv = _pmbus_write_word_data(client, page, + pmbus_fan_command_registers[id], command); + +out: + mutex_lock(&data->update_lock); + return rv; } EXPORT_SYMBOL_GPL(pmbus_update_fan);