[XFS] fix a couple of kmem issues, check for OOM in kmem_relalloc more

and in the out of mem case, panic in the sleep case, not the 
non-sleep case.

SGI Modid: 2.5.x-xfs:slinx:140364a

fs/xfs/support/kmem.c

@@ -139,7 +139,7 @@ kmem_alloc(size_t size, int flags)
 	}
 
 	rval = __vmalloc(size, flag_convert(flags), PAGE_KERNEL);
-	if (!rval && !(flags & KM_SLEEP))
+	if (!rval && (flags & KM_SLEEP))
 		panic("kmem_alloc: NULL memory on KM_SLEEP request!");
 
 	return rval;
@@ -176,7 +176,9 @@ kmem_realloc(void *ptr, size_t newsize, size_t oldsize, int flags)
 
 	new = kmem_alloc(newsize, flags);
 	if (ptr) {
-		memcpy(new, ptr, ((oldsize < newsize) ? oldsize : newsize));
+		if (new)
+			memcpy(new, ptr,
+				((oldsize < newsize) ? oldsize : newsize));
 		kmem_free(ptr, oldsize);
 	}