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Member "aoe-aoe6-86/conf/31.txt" (4 Jul 2015, 1801 Bytes) of archive /linux/misc/aoe-aoe6-86.tar.gz:


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    1 In 2.6.31, elv_next_request and blk_dequeue_request are gone.
    2 
    3 commit 9934c8c04561413609d2bc38c6b9f268cba774a4
    4 Author: Tejun Heo <tj@kernel.org>
    5 Date:   Fri May 8 11:54:16 2009 +0900
    6 
    7     block: implement and enforce request peek/start/fetch
    8     
    9     Till now block layer allowed two separate modes of request execution.
   10     A request is always acquired from the request queue via
   11     elv_next_request().  After that, drivers are free to either dequeue it
   12     or process it without dequeueing.  Dequeue allows elv_next_request()
   13     to return the next request so that multiple requests can be in flight.
   14     
   15     Executing requests without dequeueing has its merits mostly in
   16     allowing drivers for simpler devices which can't do sg to deal with
   17     segments only without considering request boundary.  However, the
   18     benefit this brings is dubious and declining while the cost of the API
   19     ambiguity is increasing.  Segment based drivers are usually for very
   20     old or limited devices and as converting to dequeueing model isn't
   21     difficult, it doesn't justify the API overhead it puts on block layer
   22     and its more modern users.
   23     
   24     Previous patches converted all block low level drivers to dequeueing
   25     model.  This patch completes the API transition by...
   26     
   27     * renaming elv_next_request() to blk_peek_request()
   28     
   29     * renaming blkdev_dequeue_request() to blk_start_request()
   30     
   31     * adding blk_fetch_request() which is combination of peek and start
   32     
   33     * disallowing completion of queued (not started) requests
   34     
   35     * applying new API to all LLDs
   36     
   37     Renamings are for consistency and to break out of tree code so that
   38     it's apparent that out of tree drivers need updating.
   39     
   40     [ Impact: block request issue API cleanup, no functional change ]