From: NeilBrown <neilb@suse.com>
Date: Mon, 3 Aug 2015 07:09:57 +0000 (+1000)
Subject: md/raid5: don't let shrink_slab shrink too far.
X-Git-Tag: omap-for-v4.3/fixes-merge-window~137^2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=49895bcc7e566ba455eb2996607d6fbd3447ce16;p=pandora-kernel.git

md/raid5: don't let shrink_slab shrink too far.

I have a report of drop_one_stripe() called from
raid5_cache_scan() apparently finding ->max_nr_stripes == 0.

This should not be allowed.

So add a test to keep max_nr_stripes above min_nr_stripes.

Also use a 'mask' rather than a 'mod' in drop_one_stripe
to ensure 'hash' is valid even if max_nr_stripes does reach zero.


Fixes: edbe83ab4c27 ("md/raid5: allow the stripe_cache to grow and shrink.")
Cc: stable@vger.kernel.org (4.1 - please release with 2d5b569b665)
Reported-by: Tomas Papan <tomas.papan@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.com>
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