Fix the lockdep error reported by Fengguang where down_read slqb_lock
is taken twice when reading /proc/slabinfo, with the possibility for a
deadlock.
Reported-by: Wu Fengguang <fengguang.wu@intel.com>
Tested-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>