md: linear: Fix a division by zero bug for very small arrays.
authorAndre Noll <maan@systemlinux.org>
Thu, 6 Nov 2008 08:41:24 +0000 (19:41 +1100)
committerNeilBrown <neilb@suse.de>
Thu, 6 Nov 2008 08:41:24 +0000 (19:41 +1100)
commitf1cd14ae52985634d0389e934eba25b5ecf24565
tree131e1fedd27d63d30896233d695594508bdbd04f
parenta53a6c85756339f82ff19e001e90cfba2d6299a8
md: linear: Fix a division by zero bug for very small arrays.

We currently oops with a divide error on starting a linear software
raid array consisting of at least two very small (< 500K) devices.

The bug is caused by the calculation of the hash table size which
tries to compute sector_div(sz, base) with "base" being zero due to
the small size of the component devices of the array.

Fix this by requiring the hash spacing to be at least one which
implies that also "base" is non-zero.

This bug has existed since about 2.6.14.

Cc: stable@kernel.org
Signed-off-by: Andre Noll <maan@systemlinux.org>
Signed-off-by: NeilBrown <neilb@suse.de>
drivers/md/linear.c