[PATCH AUTOSEL for 3.18 008/101] xen: avoid type warning in xchg_xen_ulong

From: Arnd Bergmann [ Upstream commit 9cc91f212111cdcbefa02dcdb7dd443f224bf52c ] The improved type-checking version of container_of() triggers a warning for xchg_xen_ulong, pointing out that 'xen_ulong_t' is unsigned, but atomic64_t contains a signed value:

[PATCH AUTOSEL for 3.18 008/101] xen: avoid type warning in xchg_xen_ulong

From: Arnd Bergmann [ Upstream commit 9cc91f212111cdcbefa02dcdb7dd443f224bf52c ] The improved type-checking version of container_of() triggers a warning for xchg_xen_ulong, pointing out that 'xen_ulong_t' is unsigned, but atomic64_t contains a signed value: drivers/xen/events/events_2l.c: In