From 898bd37a92063e46bc8d7b870781cecd66234f92 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Thu, 18 Apr 2019 19:45:00 -0300 Subject: docs: block: convert to ReST Rename the block documentation files to ReST, add an index for them and adjust in order to produce a nice html output via the Sphinx build system. At its new index.rst, let's add a :orphan: while this is not linked to the main index.rst file, in order to avoid build warnings. Signed-off-by: Mauro Carvalho Chehab --- Documentation/block/request.rst | 99 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 99 insertions(+) create mode 100644 Documentation/block/request.rst (limited to 'Documentation/block/request.rst') diff --git a/Documentation/block/request.rst b/Documentation/block/request.rst new file mode 100644 index 000000000000..747021e1ffdb --- /dev/null +++ b/Documentation/block/request.rst @@ -0,0 +1,99 @@ +============================ +struct request documentation +============================ + +Jens Axboe 27/05/02 + + +.. FIXME: + No idea about what does mean - seems just some noise, so comment it + + 1.0 + Index + + 2.0 Struct request members classification + + 2.1 struct request members explanation + + 3.0 + + + 2.0 + + + +Short explanation of request members +==================================== + +Classification flags: + + = ==================== + D driver member + B block layer member + I I/O scheduler member + = ==================== + +Unless an entry contains a D classification, a device driver must not access +this member. Some members may contain D classifications, but should only be +access through certain macros or functions (eg ->flags). + + + +=============================== ======= ======================================= +Member Flag Comment +=============================== ======= ======================================= +struct list_head queuelist BI Organization on various internal + queues + +``void *elevator_private`` I I/O scheduler private data + +unsigned char cmd[16] D Driver can use this for setting up + a cdb before execution, see + blk_queue_prep_rq + +unsigned long flags DBI Contains info about data direction, + request type, etc. + +int rq_status D Request status bits + +kdev_t rq_dev DBI Target device + +int errors DB Error counts + +sector_t sector DBI Target location + +unsigned long hard_nr_sectors B Used to keep sector sane + +unsigned long nr_sectors DBI Total number of sectors in request + +unsigned long hard_nr_sectors B Used to keep nr_sectors sane + +unsigned short nr_phys_segments DB Number of physical scatter gather + segments in a request + +unsigned short nr_hw_segments DB Number of hardware scatter gather + segments in a request + +unsigned int current_nr_sectors DB Number of sectors in first segment + of request + +unsigned int hard_cur_sectors B Used to keep current_nr_sectors sane + +int tag DB TCQ tag, if assigned + +``void *special`` D Free to be used by driver + +``char *buffer`` D Map of first segment, also see + section on bouncing SECTION + +``struct completion *waiting`` D Can be used by driver to get signalled + on request completion + +``struct bio *bio`` DBI First bio in request + +``struct bio *biotail`` DBI Last bio in request + +``struct request_queue *q`` DB Request queue this request belongs to + +``struct request_list *rl`` B Request list this request came from +=============================== ======= ======================================= -- cgit v1.2.3-55-g7522