On 06/19/2018 09:54 AM, Moritz Fischer wrote:
> Add __packed attribute to DMA descriptor structure in order to
> make sure that the DMA engine's alignemnt requirements are met.
>
> Fixes commit 492caffa8a1a ("net: ethernet: nixge: Add support for
> National Instruments XGE netdev")
> Signed-off-by: Moritz Fischer <m...@kernel.org>
> ---
>
> Hi David,
>
> this addresses an issue where padding occured breaking the alignment
> in the array the descriptors are allocated in coherent memory.
> This was discovered when we tried to bring up the driver via a PCIe
> bridge on x86.
How could padding be inserted given than all of the structure members
are naturally aligned (all u32 type). Compiler bug?
Also
>
> Thanks,
>
> Moritz
>
> ---
> drivers/net/ethernet/ni/nixge.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/ni/nixge.c b/drivers/net/ethernet/ni/nixge.c
> index 09f674ec0f9e..fea0e994324b 100644
> --- a/drivers/net/ethernet/ni/nixge.c
> +++ b/drivers/net/ethernet/ni/nixge.c
> @@ -122,7 +122,7 @@ struct nixge_hw_dma_bd {
> u32 sw_id_offset;
> u32 reserved5;
> u32 reserved6;
> -};
> +} __packed;
>
> struct nixge_tx_skb {
> struct sk_buff *skb;
>
--
Florian
