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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?WIrm7lyr11ondb9zM/aFtj1gKgk8kypk8TAM2g+Ohof+5WQlgtD6zGVPj+Qj?= =?us-ascii?Q?Fl/MRzepnMFlWaP+kwU9gjhd02anG8z5ZTflf6LYu+ClIguvgmZIH1trgYIR?= =?us-ascii?Q?xpyX4jFk+mQH/otJqXtEelOmF0//lkOX7LVVqlCazvFwry5EU7dmu7JNJT/W?= =?us-ascii?Q?IbGi6+a3YEyzdP/EZUUe3nrTxRbrRZDNSHUnwQzjhjLJiSehNgJ8L+6UzAPV?= =?us-ascii?Q?dDiNnwHotXKiFihodbBo+fEfI9W9aOKkkT0AlLxUbPwVzVgwuLl/IAV6kHSk?= =?us-ascii?Q?Kzy9/VaCvcedh+Ekb8EKVC7l56CzmOv5ObfYMSjBWAnrfSoPrNwnCy5NnRdU?= =?us-ascii?Q?+FtCnuU/ZC3EWU1Q5bSAez3Rz0iUWDmQskAPeHnSo6sutK7XR5O2RLiUuC/r?= =?us-ascii?Q?TIh2Opz5P54jcYUxkqzjzr+dfuklzkPQHeF1CQUTNTlOgTAHwWNUkyQLDi3E?= =?us-ascii?Q?NDPoW5DvCmJyWmxlu3tHIfhbRrBWcq2jwEo4eXMYF6sudilgr+NzPPVAXOBs?= =?us-ascii?Q?W6uDfUElRNq/ZzmcZcSEdDnPL0FMBctSTiRLhtrsd3gRRYkZvoBJZH9wsh0x?= =?us-ascii?Q?GbgOffPEcvqnuzeH3DQD7hxNGedeVFBu5LMfUDfI8tj0JD0NoO/jMCEwwEGj?= =?us-ascii?Q?7Zi4xjZGRB85BK8gVagzsgxl6saeseYWtOB89bfaFHfEn7HIk8Qq6sZMkaUV?= =?us-ascii?Q?yJP5GoHZqlylAB4zzpIdOnati8J4GDK/OEUABB6jkmNyPeclWcz3JebExSLH?= =?us-ascii?Q?ojb86TGjorvvhaPeWb0Yty2WVHv32UrZhDB58hWeKWGUhdof5c/zfJOiZVOT?= =?us-ascii?Q?CJZCc/8139A05YvEL0fjDybsXnGcOzdz+mYd84MuTyf9vfyb2aP1taw2oHX/?= =?us-ascii?Q?K0wCh7XR/H/K7aaltZN8NRbRjuDiXGsAQd9dLyhJq4YfT2SK73apbNYHwsJd?= =?us-ascii?Q?3zR8++zrasGafDCm+TTNhPJkSJ1MDgMJtjv+Y9PwKG/4VF+yZvV3vgJGVFPt?= =?us-ascii?Q?4YicrggVdQoDsPXtMFzhWO14linokl4iwe5aTOUhxYvXZaAyowQpt5wfurCs?= =?us-ascii?Q?Ayh9RyF73+nepCUQNc4DUAy07tlFq34oGBkP1+a3753zs4MtmQJulZf3OBuZ?= =?us-ascii?Q?8F1Z190YLYL3QKV3jRJoJFKhU2RgBcxzG8PxQBDiQn2AWAUsEQLhYhcpZcuj?= =?us-ascii?Q?53L9khHWvM6P9qP8xVFd7/dphsBE6M7uEjQ2JGmn1fKCkKJBY/FtpAUEIEY5?= =?us-ascii?Q?dYVWF6lgfU0RkNfTzK7/pit+VVUkKfk4YFbI1g+As9p6XbLpIHR9no3K8oRY?= =?us-ascii?Q?v33Wt8tpGQ/3QrvQJMeRlNrgwRWMxq3uLTATB4vDm1ilG0jimpQPBgxrT/2X?= =?us-ascii?Q?VPGoCPEn4HUnV1Mf+lE7vxxp/vFpjRqDvwJGbqps0Rn8nFvgrd5mY4EHSgZ6?= =?us-ascii?Q?smSLlB6AP2eTUV01HAxRBefOvYtdF0qSe93p9Fi3Qzo4FDMJkG8BRLxDyuov?= =?us-ascii?Q?k8rLzPpoXpCwmf+kEClhjVMbMDbLikFkJlonRdZYJawiYwXY05H8rZBhQLWP?= =?us-ascii?Q?0feHNzp89zyUqPHP7LbSe0EVRO2Kaec+AqlfTVYtXHhrn6dgv4ER9PjPwQYz?= =?us-ascii?Q?SGZWHJfMP3Dwbx/9JF7Ar0+yL48OyXDsjmJqC5FYyMLMeziXXEes+OYa4KgX?= =?us-ascii?Q?5okmJIxxdB9AxsqQWPd+OzFWlm0XzrT0CAAYw0BwF9WQUj40YsjQQ+uWqIJ+?= =?us-ascii?Q?MlBpJt8puB7ETX/Bjze8q8/K1KeWGNB4KYXANyzSR2LWPBEqi39e?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: bdfef69d-b376-4a04-fa4d-08dea4995fc0 X-MS-Exchange-CrossTenant-AuthSource: CY8PR12MB8300.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 Apr 2026 20:12:57.8040 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: L4Ck4zF95sPRkpw+1DBvmDDt+EvJGjHXhYAqkKsZVyTO5WLUeoARd7Y3XQH+qd9LnDnkEcQd9xWJtVVZZwcboA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: LV3PR12MB9166 On Mon, Apr 27, 2026 at 07:13:50PM +0200, Christophe Leroy (CS GROUP) wrote: > copy_{to/from}_user() is a heavy function optimised for copy of large > blocs of memory between user and kernel space. > > When the number of bytes to be copied is known at build time and small, > using scoped user access removes the burden of that optimisation. > > Signed-off-by: Christophe Leroy (CS GROUP) > --- > include/linux/uaccess.h | 47 +++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 47 insertions(+) > > diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h > index 33b7d0f5f808..3ac544527af2 100644 > --- a/include/linux/uaccess.h > +++ b/include/linux/uaccess.h > @@ -50,6 +50,8 @@ > #define mask_user_address(src) (src) > #endif > > +#define SMALL_COPY_USER 64 Let's make it L1_CACHE_BYTES, and maybe configurable?