tree 91c098468b96b959f88e1e2a386c6e8911db7c09
parent 768a418db102bb6aa6064e6090892b5c21ff1f9e
author NeilBrown <neilb@suse.de> 1275385048 +1000
committer NeilBrown <neilb@suse.de> 1280112747 +1000

raid5: Don't set read-ahead when there is no queue

dm-raid456 does not provide a 'queue' for raid5 to use,
so we must make raid5 stop depending on the queue.

First: read_ahead
dm handles read-ahead adjustment fully in userspace, so
simply don't do any readahead adjustments if there is
no queue.

Also re-arrange code slightly so all the accesses to ->queue are
together.

Finally, move the blk_queue_merge_bvec function into the 'if' as
the ->split_io setting in dm-raid456 has the same effect.

Signed-off-by: NeilBrown <neilb@suse.de>