18c2ecf20Sopenharmony_ci============================ 28c2ecf20Sopenharmony_cistruct request documentation 38c2ecf20Sopenharmony_ci============================ 48c2ecf20Sopenharmony_ci 58c2ecf20Sopenharmony_ciJens Axboe <jens.axboe@oracle.com> 27/05/02 68c2ecf20Sopenharmony_ci 78c2ecf20Sopenharmony_ci 88c2ecf20Sopenharmony_ci.. FIXME: 98c2ecf20Sopenharmony_ci No idea about what does mean - seems just some noise, so comment it 108c2ecf20Sopenharmony_ci 118c2ecf20Sopenharmony_ci 1.0 128c2ecf20Sopenharmony_ci Index 138c2ecf20Sopenharmony_ci 148c2ecf20Sopenharmony_ci 2.0 Struct request members classification 158c2ecf20Sopenharmony_ci 168c2ecf20Sopenharmony_ci 2.1 struct request members explanation 178c2ecf20Sopenharmony_ci 188c2ecf20Sopenharmony_ci 3.0 198c2ecf20Sopenharmony_ci 208c2ecf20Sopenharmony_ci 218c2ecf20Sopenharmony_ci 2.0 228c2ecf20Sopenharmony_ci 238c2ecf20Sopenharmony_ci 248c2ecf20Sopenharmony_ci 258c2ecf20Sopenharmony_ciShort explanation of request members 268c2ecf20Sopenharmony_ci==================================== 278c2ecf20Sopenharmony_ci 288c2ecf20Sopenharmony_ciClassification flags: 298c2ecf20Sopenharmony_ci 308c2ecf20Sopenharmony_ci = ==================== 318c2ecf20Sopenharmony_ci D driver member 328c2ecf20Sopenharmony_ci B block layer member 338c2ecf20Sopenharmony_ci I I/O scheduler member 348c2ecf20Sopenharmony_ci = ==================== 358c2ecf20Sopenharmony_ci 368c2ecf20Sopenharmony_ciUnless an entry contains a D classification, a device driver must not access 378c2ecf20Sopenharmony_cithis member. Some members may contain D classifications, but should only be 388c2ecf20Sopenharmony_ciaccess through certain macros or functions (eg ->flags). 398c2ecf20Sopenharmony_ci 408c2ecf20Sopenharmony_ci<linux/blkdev.h> 418c2ecf20Sopenharmony_ci 428c2ecf20Sopenharmony_ci=============================== ======= ======================================= 438c2ecf20Sopenharmony_ciMember Flag Comment 448c2ecf20Sopenharmony_ci=============================== ======= ======================================= 458c2ecf20Sopenharmony_cistruct list_head queuelist BI Organization on various internal 468c2ecf20Sopenharmony_ci queues 478c2ecf20Sopenharmony_ci 488c2ecf20Sopenharmony_ci``void *elevator_private`` I I/O scheduler private data 498c2ecf20Sopenharmony_ci 508c2ecf20Sopenharmony_ciunsigned char cmd[16] D Driver can use this for setting up 518c2ecf20Sopenharmony_ci a cdb before execution, see 528c2ecf20Sopenharmony_ci blk_queue_prep_rq 538c2ecf20Sopenharmony_ci 548c2ecf20Sopenharmony_ciunsigned long flags DBI Contains info about data direction, 558c2ecf20Sopenharmony_ci request type, etc. 568c2ecf20Sopenharmony_ci 578c2ecf20Sopenharmony_ciint rq_status D Request status bits 588c2ecf20Sopenharmony_ci 598c2ecf20Sopenharmony_cikdev_t rq_dev DBI Target device 608c2ecf20Sopenharmony_ci 618c2ecf20Sopenharmony_ciint errors DB Error counts 628c2ecf20Sopenharmony_ci 638c2ecf20Sopenharmony_cisector_t sector DBI Target location 648c2ecf20Sopenharmony_ci 658c2ecf20Sopenharmony_ciunsigned long hard_nr_sectors B Used to keep sector sane 668c2ecf20Sopenharmony_ci 678c2ecf20Sopenharmony_ciunsigned long nr_sectors DBI Total number of sectors in request 688c2ecf20Sopenharmony_ci 698c2ecf20Sopenharmony_ciunsigned long hard_nr_sectors B Used to keep nr_sectors sane 708c2ecf20Sopenharmony_ci 718c2ecf20Sopenharmony_ciunsigned short nr_phys_segments DB Number of physical scatter gather 728c2ecf20Sopenharmony_ci segments in a request 738c2ecf20Sopenharmony_ci 748c2ecf20Sopenharmony_ciunsigned short nr_hw_segments DB Number of hardware scatter gather 758c2ecf20Sopenharmony_ci segments in a request 768c2ecf20Sopenharmony_ci 778c2ecf20Sopenharmony_ciunsigned int current_nr_sectors DB Number of sectors in first segment 788c2ecf20Sopenharmony_ci of request 798c2ecf20Sopenharmony_ci 808c2ecf20Sopenharmony_ciunsigned int hard_cur_sectors B Used to keep current_nr_sectors sane 818c2ecf20Sopenharmony_ci 828c2ecf20Sopenharmony_ciint tag DB TCQ tag, if assigned 838c2ecf20Sopenharmony_ci 848c2ecf20Sopenharmony_ci``void *special`` D Free to be used by driver 858c2ecf20Sopenharmony_ci 868c2ecf20Sopenharmony_ci``char *buffer`` D Map of first segment, also see 878c2ecf20Sopenharmony_ci section on bouncing SECTION 888c2ecf20Sopenharmony_ci 898c2ecf20Sopenharmony_ci``struct completion *waiting`` D Can be used by driver to get signalled 908c2ecf20Sopenharmony_ci on request completion 918c2ecf20Sopenharmony_ci 928c2ecf20Sopenharmony_ci``struct bio *bio`` DBI First bio in request 938c2ecf20Sopenharmony_ci 948c2ecf20Sopenharmony_ci``struct bio *biotail`` DBI Last bio in request 958c2ecf20Sopenharmony_ci 968c2ecf20Sopenharmony_ci``struct request_queue *q`` DB Request queue this request belongs to 978c2ecf20Sopenharmony_ci 988c2ecf20Sopenharmony_ci``struct request_list *rl`` B Request list this request came from 998c2ecf20Sopenharmony_ci=============================== ======= ======================================= 100