[PATCH] fix kmem_cache_size() for new slab poisoning

[Christoph Hellwig <hch@xxxxxxx>]

The new slab poisoning code broke kmem_cache_size(), it now returns
a too large size as the poisoning area after the object is includes.
XFS's kmem_zone_zalloc thus overwrites exactly that area and triggers
the new checks everytime such an object is freed again.

I don't recommend using XFS on BK-current without this patch applied :)


--- 1.68/mm/slab.c      Sat Mar  8 23:50:36 2003
+++ edited/mm/slab.c    Tue Mar 11 15:15:44 2003
@@ -2041,11 +2041,16 @@
 
 unsigned int kmem_cache_size(kmem_cache_t *cachep)
 {
+       unsigned int objlen = cachep->objsize;
+
 #if DEBUG
        if (cachep->flags & SLAB_RED_ZONE)
-               return (cachep->objsize - 2*BYTES_PER_WORD);
+               objlen -= 2*BYTES_PER_WORD;
+       if (cachep->flags & SLAB_STORE_USER)
+               objlen -= BYTES_PER_WORD;
 #endif
-       return cachep->objsize;
+
+       return objlen;
 }
 
 kmem_cache_t * kmem_find_general_cachep (size_t size, int gfpflags)