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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?N8APAuMzrEzSO9hQcK950ZbXSTGdftQ1k1kd8SDSVs7HEaj9D9uwImmv26Va?= =?us-ascii?Q?ajPsVjutP6l6AbknpXIBuQPVVWTX8dnu1mEP4bsOMAF5/zhSYrFJn9E3T1s9?= =?us-ascii?Q?nahGeshBiQFNFJhuzGG8vAekJzpukKxTUAmai9Tp2HqTenBcLBOg58WL63uw?= =?us-ascii?Q?Lkk0C8s6ChTJtVMbspHUZ2IDSk2GjLSU0q1hgiRN1aE9CgUHb7X0pZwovW45?= =?us-ascii?Q?VomX55uceC/6Qruf0WnJ85Ov8YA0WICSiC9F/i6Zx9gUhnpx3Hb53RoYU++Z?= =?us-ascii?Q?CSkbm5Q0yFqKpRVgmcuMnIIXPvl65kft9OXSC989i0ki2qOFin4rFJzwqF8/?= =?us-ascii?Q?LX3tKTc08PvU/DyNLLlUoVwmUomGntkfFhwIsNEnl9GcHajH4haqQ2T0Uezm?= =?us-ascii?Q?sAgwmvsVTztAWBm/Y+8YB2cpzqgyegwrYF1HZCIe6EkV2jPd3VpLCNAX68hQ?= =?us-ascii?Q?J36hcznKo1m4DLiOMhqIbpcIIbYg9NR6xa+MpWLnNaBadr2THbbLZnR8TL8R?= =?us-ascii?Q?xmp2b/DQMKTADjAvgoTKeyS9A7VcYalzUIg5B8Z6twUZ5swDqMYWVlFZQGyC?= =?us-ascii?Q?sdO2y9+1nPKp4VN/21wi899WHfQgnUgZjLZ9GKO9SsBsC27t/NQ57jN7gNa/?= =?us-ascii?Q?2aGwGXZAGLOkTKrjpZnaIo077gJBPjP4Or/ZgwcmlE4lkuObBO303/Kmz30Q?= =?us-ascii?Q?uXOVSXy1ZdUzYxpFo8v1Ucyp0q+S6pic8HkL7vWwCuFl5dGNu7x4mFxAgzFB?= =?us-ascii?Q?PVv+HKvGwPv7JEnwz0DDjViiWni/E8SAlPkjo0qlc4MKsEt+Mb0+YxPtR4kt?= =?us-ascii?Q?Qq6Dhf1xPUAXRaOQCKJlefNua6+hOaEpLSS+XJR1cEztrzr21fj5MFGQm05r?= =?us-ascii?Q?EL10VY9QHQakoHmuGVwTebnO0ir0/a+WmV5o6xww7ZHAIdPrOe7gRupfwe5J?= =?us-ascii?Q?pZjY5gp4fP6rIVocx1S+9jcSY9aHvco1SiKYwBhX/VjrnsFiaQG5TUz+lGeu?= =?us-ascii?Q?oIDaDAfMk8WjH0pNs0YPSqjSljpefrKwTZ5gtkVgLYrGLaseN4+0f+DJHxEt?= =?us-ascii?Q?Ip3o/HSFTGqQv6W7HwMYLgvnpJ9IS3Le4pY1tHqrB//DFl1SuYCRe1Xvrqx4?= =?us-ascii?Q?9jofoeP1vj04Z5iH30L+0Z026qHFHTrL93/Pb6An4jyc3InJqExD1tCKMlF3?= =?us-ascii?Q?2Ct8w6yWkcAp5EVq+5hUNF3SHavP0DWgMzETfKWKtL7rh459QgSXbfS8Ssw7?= =?us-ascii?Q?lIY5vDCaX2tr2OAVFCThw4N8LZvcAs680tIe23Dzp0zPibcjEP54MRDZgf5W?= =?us-ascii?Q?muFkwcTUgZ9FOrLnZQvo1nlk?= X-OriginatorOrg: suse.com X-MS-Exchange-CrossTenant-Network-Message-Id: 1da4eb61-7fcd-48d8-ca7f-08d97c34317a X-MS-Exchange-CrossTenant-AuthSource: AM7PR04MB6821.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Sep 2021 12:43:06.1184 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: f7a17af6-1c5c-4a36-aa8b-f5be247aa4ba X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: LWrfybYe2rwv75r9pR457S6E7jwYNlEB8njAabaHCvNfu3O2bsc1XpC7+hpQsmsN X-MS-Exchange-Transport-CrossTenantHeadersStamped: AS8PR04MB8167 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 2021/9/20 20:41, David Sterba wrote: > On Mon, Sep 20, 2021 at 06:33:14PM +0800, Qu Wenruo wrote: >> >> >> On 2021/9/17 20:49, Nikolay Borisov wrote: >>> >>> >>> On 17.09.21 =D0=B3. 15:43, David Sterba wrote: >>>> So should we add another helper that takes the exact number and drop t= he >>>> parameter everwhere is 0 so it's just btrfs_io_bio_alloc() with the >>>> fallback? >>> >>> But by adding another helper we just introduce more indirection. >>> >>> Actually I'd argue that if 0 is a sane default then BIO_MAX_VECS cannot >>> be any worse because: >>> >>> a) It's a number which is as good as 0 >>> b) It's even named. So this is technically better than a plain 0 >>> >> >> Any final call on this? >> >> I hope this could be an example for future optional parameters. >> >> We have some existing codes using two different inline functions, and >> both of them call a internal but exported function with "__" prefix. >> >> We also have call sites passing all needed parameters just like Nikolay >> suggested. >=20 > I'm fine with explicitly using BIO_MAX_VECS instead of 0. I'll update it > in the patch, no need to resend. >=20 Thank you very much. I'll no longer use this tricky way any more. Thanks, Qu