From: NeilBrown Date: Mon, 8 Mar 2010 05:44:38 +0000 (+1100) Subject: md: deal with merge_bvec_fn in component devices better. X-Git-Tag: v2.6.34-rc2~17^2 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=627a2d3c29427637f4c5d31ccc7fcbd8d312cd71;p=pandora-kernel.git md: deal with merge_bvec_fn in component devices better. If a component device has a merge_bvec_fn then as we never call it we must ensure we never need to. Currently this is done by setting max_sector to 1 PAGE, however this does not stop a bio being created with several sub-page iovecs that would violate the merge_bvec_fn. So instead set max_segments to 1 and set the segment boundary to the same as a page boundary to ensure there is only ever one single-page segment of IO requested at a time. This can particularly be an issue when 'xen' is used as it is known to submit multiple small buffers in a single bio. Signed-off-by: NeilBrown Cc: stable@kernel.org --- Reading git-diff-tree failed