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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?6aIa/Tlah9PunQP6btaBmJ6mBI7OnzWJUN+1bH0O2QJowecMHeLkrqZH9ibn?= =?us-ascii?Q?G/4DgBVSmAMjA6xBLZHZDiam28PZP5uKmgKKgIW6BUmt2r/pXSsT6zEmw/wI?= =?us-ascii?Q?9QptVDMOCDJu/oFRkjfKQeMmMI1f+n9EB/BKxjQ6MdB7o+M/qrCDP/zm9RUI?= =?us-ascii?Q?i8QrIbzkdXBv1zYTp0x7wU7nKvGR3tc4DwhvviDr4HZO8wrVsqluQtAY9owT?= =?us-ascii?Q?qkPra+FNMNlT8YREidiXmRNqMgVbKR00lteCH8HU5wmb3n2Gya1qA+AXNxmM?= =?us-ascii?Q?Ob5f5eCdtkUPlhimLLL/b+CaY639fgvjHVPZBuGwDcrYyETNX5yAdSrPVYAB?= =?us-ascii?Q?rncaIstm3bk/ofm6Sv9gfWnd0KmkDwHpD1A0pOL6BPuyjM3coRKILlKm9/p/?= =?us-ascii?Q?FCa30+Gp6eKKKR8EeGJTqYKkAHN5q2rrbG5A6uzQtuGU/0E6njovDShpOgrk?= =?us-ascii?Q?/U2lGaQGLEfvOMhEokDobQBIicc92zJoNWOYydLCMnO+sUF1MOjEgjzuXyBN?= =?us-ascii?Q?HW/KPtFtTCGS5ecp8jMeXJAhISPE16KISi6pLmHmNIwxYlMewfapV4yLHb42?= =?us-ascii?Q?Eco7oaoHQRH891U2Sc+bb+6tQQDtWd+jRHT8uiFdamu5B8tz4B5QkMHcUJbp?= =?us-ascii?Q?QPhWxYCSPQxw3kmLF2VaIvjFpzobACog/LJHdFUkCorRwLx1n8qVjsA9SwX6?= =?us-ascii?Q?b918dryDHzb9A/cOhsA9ZnWySCGcRFQ5qyoqSvlPKy42qmQxbkVoaeoeXRSP?= =?us-ascii?Q?S+jVq65jtjhi6fVE+18CrJdxrUgUpQ8Cj65Zj27zkqYg1M2vDEAEWAPVIE6K?= =?us-ascii?Q?u3l+I+JJqxV2RlGJlwe+l1+igkt4hJZzWvoyJTJICyQ4yJDJpC3pXHyUduRy?= =?us-ascii?Q?zm6TEkK/tsGyLzwnFRY3TqjvEGO9zLuZIz77A5RSUApluEd2F/XxaGcAzyIS?= =?us-ascii?Q?3NCIQ0F74PLxdC1UlUaAG9Ev2Zidj5kkC2oau1ZIhzT/xYWPWYXPl67R/B9n?= =?us-ascii?Q?K3fnUifBx5CE4UhedbEWgQy6woygOczZVaW7TZesARqTVmu2ECgAbh+q6kTC?= =?us-ascii?Q?s7YlTi8wyHGiSc/oggS5wxY8BgiEVugbetwnZYPPZK1Kzv+OQ1QnFPL+Ltwy?= =?us-ascii?Q?6jFX5Fe+E8HDFX54zwdAzOEpHVElVzvjx82Tn3miPNWhWmt3FZal1gisRvjZ?= =?us-ascii?Q?8L3fA5GtLNbyFUKWaNxXERxS90+iTFkEjcSwIP9aUg4AZ9/31BLWclvuWgCi?= =?us-ascii?Q?6bgZ3Fau+WES7dZXdVGCAJXbVwCZcXyFPVa3w17R6ApYgjRcx6YWxCs2IHKL?= =?us-ascii?Q?2NWDHRBEqORrpK9wazlM3uvdYVkPcuA2dfk6qD6INWAT29Nctev63RWnLpup?= =?us-ascii?Q?4OkvNOJj1cmQ4gJ68q2k07W5oGWXpY74xvEmfufkEaGx/m9MR7qwm3SaMl2C?= =?us-ascii?Q?xFeYpWulCi6ZKQ64FzkJ6x6E8z0zbeoB6f5o+Yu31ExMEO3ISXTUxC22/uVW?= =?us-ascii?Q?c4QAwGNkrkO0QHvldVRyv8N75m4aTSiqxhjStZ55j4QUyMIw3cQKioqBJQRz?= =?us-ascii?Q?/TWA2xttrn7X3EGQy64=3D?= X-OriginatorOrg: zenithal.me X-MS-Exchange-CrossTenant-Network-Message-Id: 4f64d819-fbb7-4ac7-8bfa-08da55fac987 X-MS-Exchange-CrossTenant-AuthSource: TYCP286MB1393.JPNP286.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 24 Jun 2022 16:01:23.9665 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 436d481c-43b1-4418-8d7f-84c1e4887cf0 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: ZEcmpra68uHL6MGfZlwbAhMOVrJ1kBd7sapYh0AGR1qoXjzoZGCM0XCiDId92OSb X-MS-Exchange-Transport-CrossTenantHeadersStamped: TYCP286MB2733 Precedence: bulk List-ID: X-Mailing-List: linux-can@vger.kernel.org On Fri, Jun 24, 2022 at 10:43:34AM -0400, Alan Stern wrote: > > > > > One way to solve this issue for usbip > > > is to add some boilerplate transform > > > from URB_* to USBIP_FLAGS_* > > > as it is de facto uapi now. > > > > It doesn't sound like a there is a compelling reason other than > > "it would be nice to keep the flag values in numerical order". > > > > I would not recommend this option. I am not seeing any value to adding > > change URB_* to USBIP_FLAGS_* layer without some serious techinical > > concerns. The transfer_flag in usbip is de facto uapi, That's why I'm proposing the USBIP_FLAGS_* way and further more I think usbip could move some flags/structs in usbip_common.h to include/uapi/linux/usb/usbip.h, instead of the userspace copying them into their own header. I will start a new thread if Shuah think that is acceptable. If this patch is to be landed, I think it should be landed along with the usbip change so there would be no userspace change; Even without this patch, making usbip flags/structs uapi alone is still worth doing. > > > > > > > > Another way is to use 0x0400 for FREE_COHERENT. > > > usbip will not take care of this bit as > > > it would be masked. > > > > > > > I would go with this option adding a clear comment with link to this > > discussion. > > > > > Cc Shuah Khan here since she is the maintainer > > > on usbip. > > > > > > > Thank you adding me to the discussion. > > I can see this causing more problems in the future. There's no hint in > include/linux/usb.h that any of the values it defines are part of a user > API. If they are, they should be moved to include/uapi/linux/usb/. I agree with this argument. > > In general, if a user program depends on kernel details that are not > designed to be part of a user API, you should expect that the program > will sometimes break from one kernel version to another. > > Yes, I know Linus insists that kernel changes should not cause > regressions in userspace, but the line has to be drawn somewhere. > Otherwise the kernel could never change at all. > > Alan Stern