tree 679af09dde4d2659bc6a7dcd1d3dc34752899fa6
parent 313e42999dbc0f234ca5909a236f78f082cb43b1
author Tejun Heo <tj@kernel.org> 1227846723 +0900
committer Jens Axboe <jens.axboe@oracle.com> 1230535724 +0100

block: remove duplicate or unused barrier/discard error paths

* Because barrier mode can be changed dynamically, whether barrier is
  supported or not can be determined only when actually issuing the
  barrier and there is no point in checking it earlier.  Drop barrier
  support check in generic_make_request() and __make_request(), and
  update comment around the support check in blk_do_ordered().

* There is no reason to check discard support in both
  generic_make_request() and __make_request().  Drop the check in
  __make_request().  While at it, move error action block to the end
  of the function and add unlikely() to q existence test.

* Barrier request, be it empty or not, is never passed to low level
  driver and thus it's meaningless to try to copy back req->sector to
  bio->bi_sector on error.  In addition, the notion of failed sector
  doesn't make any sense for empty barrier to begin with.  Drop the
  code block from __end_that_request_first().

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>