[dpdk-dev] [PATCH 03/10] net/virtio: fix compilation with -Og

[Ferruh Yigit]

On 9/11/2017 4:13 PM, Olivier Matz wrote:
> The compilation with gcc-6.3.0 and EXTRA_CFLAGS=-Og gives the following
> error:
> 
>   CC virtio_rxtx.o
>   virtio_rxtx.c: In function ‘virtio_rx_offload’:
>   virtio_rxtx.c:680:10: error: ‘csum’ may be used uninitialized in
>                         this function [-Werror=maybe-uninitialized]
>        csum = ~csum;
>        ~~~~~^~~~~~~
> 
> The function rte_raw_cksum_mbuf() may indeed return an error, and
> in this case, csum won't be initialized. Fix it by initializing csum
> to 0.

After this fix if rte_raw_cksum_mbuf() returns error csum still will be
wrong and since compiler warning suppressed it may be harder to find the
root cause.

For this case checking rte_raw_cksum_mbuf() return value seems better
idea but I will cc the maintainer for decision.

> 
> Fixes: 96cb6711939e ("net/virtio: support Rx checksum offload")
> Signed-off-by: Olivier Matz <olivier.matz at 6wind.com>
> ---
>  drivers/net/virtio/virtio_rxtx.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c
> index 45a9c919a..cab3a1675 100644
> --- a/drivers/net/virtio/virtio_rxtx.c
> +++ b/drivers/net/virtio/virtio_rxtx.c
> @@ -671,7 +671,7 @@ virtio_rx_offload(struct rte_mbuf *m, struct virtio_net_hdr *hdr)
>  			 * In case of SCTP, this will be wrong since it's a CRC
>  			 * but there's nothing we can do.
>  			 */
> -			uint16_t csum, off;
> +			uint16_t csum = 0, off;
>  
>  			rte_raw_cksum_mbuf(m, hdr->csum_start,
>  				rte_pktmbuf_pkt_len(m) - hdr->csum_start,
>