On Thu, 30 Dec 2004 03:48:35 -0500
David Dillow [off-list ref] wrote:

+static inline struct xfrm_offload *
+xfrm_offload_alloc(int sizeof_priv, struct net_device *dev)

This whole scheme looks buggy.  The intent is to 8-byte align
the object, but look at what the code is actually doing.

Whatever kmalloc() returns to xfrm_offload_alloc() is directly
used as the xfrm_offload pointer, and the members are initialized.

Then xfrm_offload_priv() does the alignments.

It is clear that kmalloc() is always giving you 8-byte aligned
data else the first time xfrm_offload_priv() is used you'd
get a bogus pointer since xfrm_offload_alloc() initialized
the object without first aligning the pointer.

We do something similar when we allocate netdevs, so have a look
at how net/core/dev.c:alloc_netdev() works.