From: NeilBrown <neilb@suse.de>
Date: Tue, 11 Jun 2013 04:57:09 +0000 (+1000)
Subject: md/raid10: locking changes for 'enough()'.
X-Git-Tag: v3.11-rc1~91^2~7
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=635f6416a2e983adac8ccf90bffbeed0c1a76454;p=pandora-kernel.git

md/raid10: locking changes for 'enough()'.

As 'enough' accesses conf->prev and conf->geo, which can change
spontanously, it should guard against changes.
This can be done with device_lock as start_reshape holds device_lock
while updating 'geo' and end_reshape holds it while updating 'prev'.

So 'error' needs to hold 'device_lock'.

On the other hand, raid10_end_read_request knows which of the two it
really wants to access, and as it is an active request on that one,
the value cannot change underneath it.

So change _enough to take flag rather than a pointer, pass the
appropriate flag from raid10_end_read_request(), and remove the locking.

All other calls to 'enough' are made with reconfig_mutex held, so
neither 'prev' nor 'geo' can change.

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

Reading git-diff-tree failed