tree e17aa5d2a7220cfe7466cc4f8c74af5ed672a591
parent 46a06401f6ba13e59d24746fa9ffa6773b69eee3
author NeilBrown <neilb@suse.de> 1343860400 +1000
committer NeilBrown <neilb@suse.de> 1343860400 +1000

md/raid1: submit IO from originating thread instead of md thread.

queuing writes to the md thread means that all requests go through the
one processor which may not be able to keep up with very high request
rates.

So use the plugging infrastructure to submit all requests on unplug.
If a 'schedule' is needed, we fall back on the old approach of handing
the requests to the thread for it to handle.

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