slab: Fix off by one in object max number tests.
If freelist_idx_t is a byte, SLAB_OBJ_MAX_NUM should be 255 not 256, and likewise if freelist_idx_t is a short, then it should be 65535 not 65536. This was leading to all kinds of random crashes on sparc64 where PAGE_SIZE is 8192. One problem shown was that if spinlock debugging was enabled, we'd get deadlocks in copy_pte_range() or do_wp_page() with the same cpu already holding a lock it shouldn't hold, or the lock belonging to a completely unrelated process. Fixes: a41adfaa ("slab: introduce byte sized index for the freelist of a slab") Signed-off-by: NDavid S. Miller <davem@davemloft.net> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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