From: Ming Lin Date: Thu, 7 May 2015 05:51:24 +0000 (-0700) Subject: md/raid5: split bio for chunk_aligned_read X-Git-Tag: omap-for-v4.3/fixes-rc1~114^2~11 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7ef6b12a1966f273afb750e19e1e8129bea48fec;p=pandora-kernel.git md/raid5: split bio for chunk_aligned_read If a read request fits entirely in a chunk, it will be passed directly to the underlying device (providing it hasn't failed of course). If it doesn't fit, the slightly less efficient path that uses the stripe_cache is used. Requests that get to the stripe cache are always completely split up as necessary. So with RAID5, ripping out the merge_bvec_fn doesn't cause it to stop work, but could cause it to take the less efficient path more often. All that is needed to manage this is for 'chunk_aligned_read' do some bio splitting, much like the RAID0 code does. Cc: Neil Brown Cc: linux-raid@vger.kernel.org Acked-by: NeilBrown Signed-off-by: Ming Lin Signed-off-by: Jens Axboe --- Reading git-diff-tree failed