From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from DUZPR83CU001.outbound.protection.outlook.com (mail-northeuropeazon11012057.outbound.protection.outlook.com [52.101.66.57]) (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 0023E295DA9; Thu, 3 Jul 2025 13:34:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.66.57 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751549701; cv=fail; b=mRzAzZa+Q8b9AGH7t8+nfvQWsma0P1JVOoZYvVzsCvHSFsfCqodPGdzlYvAu22X9qHGE0Stna+AD96SPZb9n7GlQ+UncvZvK7YNm0aEHcnQsQP2MGYcCAbhqtd60hBScvKqfxibfakiX/65k0ntzQX0rmnoGSyF6+I8UEBg3+e4= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751549701; c=relaxed/simple; bh=haU5CHY14aE2xh3RsSkWXCWeP/Tf8tyLWpHWfUZW3IY=; h=Date:From:To:Cc:Subject:Message-ID:References:Content-Type: Content-Disposition:In-Reply-To:MIME-Version; b=AU3/wqdiIB0OAV0L8rbWMD/wktXj6OKC6Qsp8ISnnCF9DfI4HIUgwxawLUqSwc+pOGHgXaQcCxEhEKWeusCGnv2eYtN1bOYOF59JXyKTqBJv8Ga7xFacHlmLiu1UE8uP3SKSsFqof5JFgvPzuC4a0WGlvbGIeescO+qyZ/zWrTY= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=nxp.com; spf=pass smtp.mailfrom=nxp.com; dkim=pass (2048-bit key) header.d=nxp.com header.i=@nxp.com header.b=GkLk8fVp; arc=fail smtp.client-ip=52.101.66.57 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=nxp.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=nxp.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=nxp.com header.i=@nxp.com header.b="GkLk8fVp" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=YDYfaga8X3AQ5eLbjE6WbPMlrgA4BP9oq/3I0cOWkADQXw2A2EE217ySFT5IPt4FTDT0BcNl14ETJ4g/K9VKebYhUf4iZbHI6uZ+Bv8NBsRNhil02EITa1Ut4jiH8SNPYK3IDKqCirH0Z1ZaprlpfyL9cTYMHTdFRq/HHgedBQcwWklHos0yTsesZerU2HO1OiDCsTDp1e6rH3fiAveyPJr1Thp8qG63EN9YeZnbMxVtD4BbgiKGbj92n2qIWqKS6OmoJZlzkO5qEkTJQLtHTI/9nyIB+XBVr4+N+kMwomPlW/qHxtCkAvlIxFXZYADCk3flaQYZBH/dzXbI5O0B+Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=CoIQjxIPTPjyizk2YRmFaBAKkrTHVVibNIhNp7mhWd4=; b=xdxHO9SuUHGBey9/a5G/lAP2kh9+cErTAjSppvbQuaP8DX81+fhIH6/KQ8EaOUdemph+MdfWZZqC0uuCTeQZrQ+LoVnrwV1ty8WEF8kMQdAVqrESyp0lFcbT2FT4kLfupPoR9lipxIpGeE+eC10P9wTM3wmdxEGN4ucX8wxywitlevySr/QO33eSjnsOl29vvbp0MnYRT2Wnk4InKyUsgfPnutqqwSTTJmE11qHfH8/Yt6ZLuMWVv95ZzQb0v9B4ovUugZTjIdREj5HFs53NyBRhK2Ua/HVXWrCajWWbSOGx8O5oy0lqQ0lYLP48m7DylyNcMkLPyNyeZbgCu8VZYA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nxp.com; dmarc=pass action=none header.from=nxp.com; dkim=pass header.d=nxp.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nxp.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=CoIQjxIPTPjyizk2YRmFaBAKkrTHVVibNIhNp7mhWd4=; b=GkLk8fVp6NyUq+fSFChcLvgku9rWEt/U0lAnrFqt/k4YjDPYxYF4TWUHs1CNM1Vqv05EH2n5l79xSKxtU0tJz48XMKd9Pfywk2YlzkcVq0kZZA5r8xypYuaNcDYt81jygwYi2ILZdRT0scBwyu0Ch+vo9gOd8vjXKk61UUQ+c+BlNRAAPC9CufNWdjWDPt4tctjtN8cpC0kbQVbCvdIQvMWAU5PX/qOdQT68gBEgITlNIXbD9uDvLMIkHGHZ3bwd9qI8dJ06WsAi3nsC/pG/UAroAaSuG463eET6N6Q/PwrjvI0Gvykke9w+epnJD8aNE+jf0xNaWICT0eZmkC3gBA== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nxp.com; Received: from AM8PR04MB7779.eurprd04.prod.outlook.com (2603:10a6:20b:24b::14) by DU2PR04MB8600.eurprd04.prod.outlook.com (2603:10a6:10:2db::12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8901.20; Thu, 3 Jul 2025 13:34:56 +0000 Received: from AM8PR04MB7779.eurprd04.prod.outlook.com ([fe80::7417:d17f:8d97:44d2]) by AM8PR04MB7779.eurprd04.prod.outlook.com ([fe80::7417:d17f:8d97:44d2%7]) with mapi id 15.20.8901.018; Thu, 3 Jul 2025 13:34:56 +0000 Date: Thu, 3 Jul 2025 16:34:50 +0300 From: Vladimir Oltean To: Jeongjun Park Cc: richardcochran@gmail.com, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next v2] ptp: remove unnecessary mutex lock in ptp_clock_unregister() Message-ID: <20250703133450.kaoncopz3i2ileug@skbuf> References: <20250703055340.55158-1-aha310510@gmail.com> <20250703055340.55158-1-aha310510@gmail.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250703055340.55158-1-aha310510@gmail.com> <20250703055340.55158-1-aha310510@gmail.com> X-ClientProxiedBy: VI1PR09CA0138.eurprd09.prod.outlook.com (2603:10a6:803:12c::22) To AM8PR04MB7779.eurprd04.prod.outlook.com (2603:10a6:20b:24b::14) Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: AM8PR04MB7779:EE_|DU2PR04MB8600:EE_ X-MS-Office365-Filtering-Correlation-Id: 38216377-a02b-4efc-cf22-08ddba36665d X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|10070799003|376014|366016|1800799024|19092799006; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?1NHERNDsAMozpfC6F+lkrvdkv7GD40t5gIpR7ISCSddAWYrKN9iBgfNq8UuM?= =?us-ascii?Q?EMeddjNu7NY3YtpGs97Gqfp2I6XPCNQmXD4iwCPvpNW17cWw4WtLW2boOuia?= =?us-ascii?Q?dll6Un3y9EpiwMB6uy7BcoNiTAc8qj//MeHkYjniZVieWXPYCl4jksood/ZO?= =?us-ascii?Q?6u1vq0K4tWyxgSxxuypEzNcKNJahwY/KUfa1xTY8ISsvZ1od/s1ZWhd886VK?= =?us-ascii?Q?Ec1/ghj9f1t+5XXVPNsDPMlmh57cg3tzdIcAOil59D4/knM6tCogBwix/Wu9?= =?us-ascii?Q?1FexxTqZVGkJkZwpd3VLgDkFXs39edYkRwD4YfPXRJ8ejfONOmTkXpRGwAkp?= =?us-ascii?Q?DrQDr5u3mjC11NrmoIkgpKHaZpvI2s83d0n76k0OTgvspHLpnKErHLy8ZiFX?= =?us-ascii?Q?dVYpMUVklg5tFa1M8RMvrTWjRYbWyXW34Zo7BPACPoekHjjfTtMvIWdN19ZU?= =?us-ascii?Q?elC8kNhqn6SXTIro1Pil85iIMEDTa2nMkrR7zGaow9NM3CXH2hbsIPpIqxfY?= =?us-ascii?Q?NcmRY73SrtE3/mmA3yiBcyd3EuoEwpUWa1EwuyhTrqavBCkuX/QcMqVMbW/k?= =?us-ascii?Q?7ckH6copNgJm3ZCrP7cFMrZtfdCCGgq9HZGnTcZ9So0bRCIXm8sbgsMYh7j9?= =?us-ascii?Q?KguFyVZN0zkfU18OaV08IUH4WS+JsurDQ8aipfMuCaL+tHDLOmaJhr7/D//w?= =?us-ascii?Q?4AXHKaURo40/nl+fedsQ6WQg395vjqU4Qe7Eu4XRrH3gBQJDy/rgtSa2Gnzt?= =?us-ascii?Q?TQe9Yv+uZdvibNUS65UF8sMZg8s2reoVtIYSxyKJdJEoDDliX9g2o8IxCzzh?= =?us-ascii?Q?RCwPRBMJE0e7jdIoDx88N0K3S4JOHsyCvZa52CWSBs/6YqUxOCT3NY+t4nfj?= =?us-ascii?Q?IIRGwVDv75s3ndQhxzFI7ALx/xbSzp0i/pS1lEvgBRVK30Q6C4yk7JfCh4q5?= =?us-ascii?Q?zxtmKPjKyiwjDoQrLooS2j22ePik9ydvf1kP0YoapFFegZO4vnVBzAbrk1AW?= =?us-ascii?Q?CNg1tLm5ruyqy3oPqVfs3ADnmjaLnLr7opheH4t2fRH+Gng+7wHXwr80jJXx?= =?us-ascii?Q?+ZYuGCQ2ZBjPl/cv6/rfpirTBxyXtJ6fq8oH86L3yP1xiwMwQtxLxnGxyNmK?= =?us-ascii?Q?d7ox7Beerd0s1cnKYK9L/clf2ujeQ57fyvlXNUkE1hHpXCOCqfj7kBiXulra?= =?us-ascii?Q?pS8Jkos/yGQalfT256la8SipY5Tu4AS1GJYcVxV1i1w/Jbd14NYtKiVMEQm+?= =?us-ascii?Q?ZaUiAGNYDIo2VWec3mSkAOjoWzbvb1z7h7YCAmK2g1AVk9KhfMCqpeYEAwxA?= =?us-ascii?Q?zlpqX4SnJcL+GtY6DDT9LeOpgaGrHT3EFiKxptF322zuY6iD1AqgQbmRyUcs?= =?us-ascii?Q?vmhKwkwPph6Wf0AzQY/8OlUcOOqFKmDz97O2V4jwAldsTMKadQ=3D=3D?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:AM8PR04MB7779.eurprd04.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(10070799003)(376014)(366016)(1800799024)(19092799006);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?RiFrzf4Bx/lXSE1vbS7Devih96amdZ4PZVhUmuLksx4OTqC7q2/v2gguxXHm?= =?us-ascii?Q?xw52euVPbNcTAUmfsKSjjwS9FKa0oMhEk9XdwN2oSpFiIxD9qW5vi+igaz/u?= =?us-ascii?Q?m84Cq2NsoywBR0tWzGBKHnFUc1UM6ZkN3c2XsAsWpjiD3KcQXlDHhD9aS0hA?= =?us-ascii?Q?V2DfSpj1r1q32qqzB3RdOjACDuhyrtILlYFiaUyTQYQ5PKdrh0pzjCvTCgee?= =?us-ascii?Q?K+N5q8gjU1gj/tw0hO3mKblNYVe7aJH0IqQ6fNhpVJPjVE5SS01/luwIaM6P?= =?us-ascii?Q?MlEATZpj8KTkNJGLaBIXdzZF2oHq9voZhY2CYklqbTMwTH+jkhhSJvSmwVgI?= =?us-ascii?Q?4XoL4iuY1N8URX18LgcMLO7AeBnxzjB65mLLJJ2iWs9cfPM2ZylagkNmj/br?= =?us-ascii?Q?luP4F+LXNWhqtiU71s8DLlEknd6DYFxzkkn9CwfJakBDiHdGcWANoMhaCw87?= =?us-ascii?Q?raohNwHeeJrkR88GnXJ9ZahBqexY1gmwN/On10FAXbKsfiiD2cW6lQTMPu0K?= =?us-ascii?Q?cY1JeuKsMEEm1t1NGXA3Jmrw0mUM+61F3tUb4+6VnuA+WyyiEnqPIYG70Ez4?= =?us-ascii?Q?UmRFeLprcOeYQUyKG6m12gRDe90qYB2cbzXeJx7CDC68s1Me/iztcBlATptC?= =?us-ascii?Q?8NjzBJc55WfqZ8+HBlp6wBXj+qdxOsJiP6jkGriQitI5VvBwKc9wDKvoSvXz?= =?us-ascii?Q?VYXzMMprKJ/uNGYEPSNsGYwEhZ0sT6YjE4a8ZshHhKaq+riOFCgnWO/7sqeD?= =?us-ascii?Q?GifRQ7qxmKTjpIt/wdt/b45d8G0L75IG5jGIIgdM+Lo/RnlVgOKZ+e+X8JGe?= =?us-ascii?Q?ffrElJk8g9sXnWfzsWnOFR9zIy+eiBdETqsQ2yMXeEYkxbtwFlmzdFI57fx2?= =?us-ascii?Q?vMXwcK7v2gQaDT8PtDzgHoWq7r7DHrIu+OESfvIRgkwOiExM1vqiB7XNJVis?= =?us-ascii?Q?WkjHLysun0Asr4UkoQXbN8SczDH6+omT05qvbYx7L/dv93LfgZxqlNpc3tPH?= =?us-ascii?Q?JqhY4DC5ss642/LodIr38nSoYg0ik+z3XGDnClaUnDqFG+eRXnkbI+/pw/6Z?= =?us-ascii?Q?xxHr205ZGxpP0e07Ti+KpHURlvp/2mTTcW8mZvHRbcdzvQa61QCVIOzW/bXi?= =?us-ascii?Q?TBvbcbvPhG896NgFSnJFxhy0Oia3Fj6Xy9D2EPfFonTHSJr61bQ/IVbOKMMF?= =?us-ascii?Q?o4gZSnB580tI4ou6BS5vH/6cJ4+hJBExXtpRYBpZtaPtbz0ZeZcARL+xmIPC?= =?us-ascii?Q?W2Bi1JfxnGC5T+fq80rc7vuoLQfVvfAGyiuszP+fnuFLdgTXzNl9rlvm8wGy?= =?us-ascii?Q?VgHHw+Jx5tfelXF2C/z5qoWZYF4QOwltsN53jkmYkny5L6UAKZwDC+SXyNkC?= =?us-ascii?Q?5WGrxLQgSgLbwZPDefG9dZF+YzSo9BVgnwWke2bj1q3hqEVwUcd0VzQwyL/5?= =?us-ascii?Q?hvdRFRERaJShgbRpq/7vayPSAjIZLrGChdAqzCZwn77vi7dwpMYHIxQ+2kMn?= =?us-ascii?Q?OKYnlwbw9HKPyPoYEJe4B4P6jaAJ8VI/ISGo2og3+B2DhaFcDVXBE5JAZQ6z?= =?us-ascii?Q?u9jxnMCvVCl+QzNT3a1OMJFMzhkaZgQgx3JFBh7SaW/y2F9BU6D2LwzHbv1f?= =?us-ascii?Q?J55FhduNWSfc95/R6doVGNr70uctu2I1Y9FJFeJvZvGDyRMvqM6UJogByo4B?= =?us-ascii?Q?7kUErg=3D=3D?= X-OriginatorOrg: nxp.com X-MS-Exchange-CrossTenant-Network-Message-Id: 38216377-a02b-4efc-cf22-08ddba36665d X-MS-Exchange-CrossTenant-AuthSource: AM8PR04MB7779.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 03 Jul 2025 13:34:56.6290 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 0vJRyvsY5gzA/zjvzs5VbkKWF23vzzCFZpMG25M0QautDToDfaKuCXOkLfVqYO3ZHFyh/kxY7n1w10/acufn3A== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DU2PR04MB8600 On Thu, Jul 03, 2025 at 02:53:40PM +0900, Jeongjun Park wrote: > ptp_clock_unregister() is called by ptp core and several drivers that > require ptp clock feature. And in this function, ptp_vclock_in_use() > is called to check if ptp virtual clock is in use, and > ptp->is_virtual_clock, ptp->n_vclocks are checked. > > It is true that you should always check ptp->is_virtual_clock to see if > you are using ptp virtual clock, but you do not necessarily need to > check ptp->n_vclocks. > > ptp->n_vclocks is a feature need by ptp sysfs or some ptp cores, so in > most cases, except for these callers, it is not necessary to check. > > The problem is that ptp_clock_unregister() checks ptp->n_vclocks even > when called by a driver other than the ptp core, and acquires > ptp->n_vclocks_mux to avoid concurrency issues when checking. > > I think this logic is inefficient, Can you present a single metric by which you qualify this logic as inefficient? > so I think it would be appropriate to modify the caller function that > must check ptp->n_vclocks to check ptp->n_vclocks in advance before > calling ptp_clock_unregister(). And which are the call sites of ptp_clock_unregister() which should check ptp->n_vclocks in advance, in your proposal?