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Miller" , Eric Dumazet , Jakub Kicinski , netdev@vger.kernel.org, Paolo Abeni Subject: Re: [PATCH net] net: phy: fix phy_uses_state_machine() Message-ID: <20250901093530.v5surl2wgpusedph@skbuf> References: <20250901084225.pmkcmn3xa7fngxvp@skbuf> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: VI1PR0202CA0003.eurprd02.prod.outlook.com (2603:10a6:803:14::16) 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_|VE1PR04MB7376:EE_ X-MS-Office365-Filtering-Correlation-Id: ddc133cb-24a3-4a15-29b0-08dde93ae651 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|10070799003|1800799024|376014|19092799006; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?sgLoet2mI16ai4SQbusK2QGFjs1k8TmF8n+wC6HZJ4szovWAU0Sj0yyEDVWC?= =?us-ascii?Q?LXrahTEBz89UxkgvbEWt2ktDxMCL0CJJ9IKPsfncoh4T8DSj5+29WtwFTj3x?= =?us-ascii?Q?//bResiJUU3rOQTp//wt01l3tT5pa0jLuvbECPHaFY5rLCXxd7jEanGAA9++?= =?us-ascii?Q?EsWpP7pscjMj8vqmBxLfSdUbyvlVhEzxGAe9Z57LPEakwCpVEX7iE/jlrags?= =?us-ascii?Q?ZI7k8PaVHNzMuitD1RCLU73zQ0hw+SIzUoFhvQLWWNFeon8gc1LvUtrRMZcE?= =?us-ascii?Q?+yjS4RemcEqNRXa9aCXgjxw9tm5v5Fdvw+DbrxXlsOj6b+0Dbr8scER9WxpO?= =?us-ascii?Q?7xcHAILhpDcl8owaHhqER5FO6ZDqXm738Hzj4DHuVqzAdaDCYfN3Hm7TxHdw?= =?us-ascii?Q?k46I7IUnirOjS5gkX7QnBEOztPuYLGcqq6wRuEktsuPbSpwbzmZcuxFbsnhW?= =?us-ascii?Q?EASLCpD79WVXiZX61ER5GaCVR+CEJ30H8pmcp20yM4WRtc1RreVjckff8qQO?= =?us-ascii?Q?QORoC6qSCuOnU8OzLFXGxfnMJDDZxu21/5EOKE53G6AKc353OMz89L5dSWH8?= =?us-ascii?Q?dvXfOiZmvEcbv5FgmtBokgn+uwPS91UXNPdQBzt4JbhmAc6WsHC8qaZOg+72?= =?us-ascii?Q?126LaTaIl6PJx2hnd6xXeK0Bz65+K6RXNWQkgLoen5555ay7Fetsr0YuV/zV?= =?us-ascii?Q?gkjLGl1vt7KaMACVh5q7iQtv0qKcFwi8gt+Q0FhwJDOmvOWn37s446i01TW6?= =?us-ascii?Q?kKBzhK9BZXT/1+i8ZgEj88u9edrAx8y+LExsNmZkrcqA50nNNZ//PNp9i7v7?= =?us-ascii?Q?qnpje+5IlVTNNpDMGdX7xfPTbUjg4ivaN+Hyrr6CR/N4PiHrJ4/8ypI3PJH7?= =?us-ascii?Q?0sU7GxHuZwJF3mO4gfAammrF+60kZjwEBgaPySd3vl2jVPRXXvgFKEN6f/1G?= =?us-ascii?Q?kZguFL7RiCqzjVWhXMqZ3lutaWkpulVJT2oVjJshEzDHjfr9Ps0RRbq9bh6v?= =?us-ascii?Q?uLFUSWmg1bjl0o9wsu87qLlU3ja9F5sao874Yg9buQI/0QVUmQvWSlBNAFBu?= =?us-ascii?Q?H+vyteYTEd43OWlldX9dvCYgLT5cYKOiDjYKtisKSBTgMqfBobeiOb/1nj6G?= =?us-ascii?Q?IsNg+rPcC+YYD7GYKb9NIpvnshtsEgVDmNfxc/7Le8CYg+sBLmAUzIuiPxPz?= =?us-ascii?Q?luP9ve35IY538hWCV9ikc+XMAqx1BNhayENktGGPcskSiGV9Y5Nl400VbGPU?= =?us-ascii?Q?3JnA5mAVDfXxrtCnmlUfKqzlfRrPW2O8XHo70Z9WcNkeS8Yt88efXlxWNdqg?= =?us-ascii?Q?wSSAhS2+5kQtpusMte1arvtU5/fxzI6WWEQibIG9pqRDMAAKVIXlvro2nUBv?= =?us-ascii?Q?sCkUxds=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)(366016)(10070799003)(1800799024)(376014)(19092799006);DIR:OUT;SFP:1101; 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This means that a never-connected PHY will > > > have phydev->phy_link_change set to NULL, which causes > > > phy_uses_state_machine() to return true. This is incorrect. > > > > Another nitpick regarding phrasing here: the never-connected PHY doesn't > > _cause_ phy_uses_state_machine() to return true. It returns true _in > > spite_ of the PHY never being connected: the non-NULL quality of > > phydev->phy_link_change is not something that phy_uses_state_machine() > > tests for. > > No. What I'm saying is that if phydev->phy_link_change is set to NULL, > _this_ causes phy_uses_state_machine() to return true and that > behaviour incorrect. > > The first part is describing _when_ phydev->phy_link_change is set to > NULL. > > It is not saying that a never-connected PHY directly causes > phy_uses_state_machine() to return true. > > I think my phrasing of this is totally fine, even re-reading it now. > > -- > RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ > FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last! I think the language is sufficiently flexible for us to find a phrasing that avoids all ambiguity. What about: "It was assumed the only two valid values for phydev->phy_link_change are phy_link_change() and phylink_phy_change(), thus phy_uses_state_machine() was oversimplified to only compare with one of these values. There is a third possible value (NULL), meaning that the PHY is unconnected, and does not use the state machine. This logic misinterprets this case as phy_uses_state_machine() == true, but in reality it should return false."