The attribute came from the FreeBSD structure this was copied from, which ends in a flexible array member for the ring data and is asserted to be page sized. DPDK computes the data offset from the page size instead and never declared that member, so nothing is left that packing affects: all remaining members are naturally aligned and the layout is identical without it.
Byte alignment does prevent atomic access to the ring indexes, which clang rejects with -Watomic-alignment. Signed-off-by: Stephen Hemminger <[email protected]> --- drivers/bus/vmbus/rte_vmbus_reg.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/bus/vmbus/rte_vmbus_reg.h b/drivers/bus/vmbus/rte_vmbus_reg.h index 6370a07f95..210328c877 100644 --- a/drivers/bus/vmbus/rte_vmbus_reg.h +++ b/drivers/bus/vmbus/rte_vmbus_reg.h @@ -69,7 +69,7 @@ struct __rte_packed_begin vmbus_mon_page { * Buffer ring */ -struct __rte_packed_begin vmbus_bufring { +struct vmbus_bufring { volatile uint32_t windex; volatile uint32_t rindex; @@ -111,7 +111,7 @@ struct __rte_packed_begin vmbus_bufring { * page aligned and starts at rte_mem_page_size() from the beginning * of this structure */ -} __rte_packed_end; +}; /* * Channel packets -- 2.53.0
