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: email@example.com (4.1 - please release with 2d5b569b665)
Reported-by: Tomas Papan <firstname.lastname@example.org>
Signed-off-by: NeilBrown <email@example.com>
1 file changed