From: Tejun Heo <htejun@gmail.com>
Date: Tue, 19 Feb 2008 10:35:38 +0000 (+0100)
Subject: block: update bio according to DMA alignment padding
X-Git-Tag: v2.6.25-rc3~122^2~5
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=40b01b9bbdf51ae543a04744283bf2d56c4a6afa;p=pandora-kernel.git

block: update bio according to DMA alignment padding

DMA start address and transfer size alignment for PC requests are
achieved using bio_copy_user() instead of bio_map_user().  This works
because bio_copy_user() always uses full pages and block DMA alignment
isn't allowed to go over PAGE_SIZE.

However, the implementation didn't update the last bio of the request
to make this padding visible to lower layers.  This patch makes
blk_rq_map_user() extend the last bio such that it includes the
padding area and the size of area pointed to by the request is
properly aligned.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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