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+============================
+struct request documentation
+============================
+
+Jens Axboe <jens.axboe@oracle.com> 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).
+
+<linux/blkdev.h>
+
+=============================== ======= =======================================
+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
+=============================== ======= =======================================