Re: [PATCH AUTOSEL 4.19 204/205] s390/qeth: limit csum offload erratum to L3 devices

From: Julian Wiedmann
Date: Fri Nov 08 2019 - 06:50:37 EST


On 08.11.19 12:37, Sasha Levin wrote:
> From: Julian Wiedmann <jwi@xxxxxxxxxxxxx>
>
> [ Upstream commit f231dc9dbd789b0f98a15941e3cebedb4ad72ad5 ]
>
> Combined L3+L4 csum offload is only required for some L3 HW. So for
> L2 devices, don't offload the IP header csum calculation.
>

NACK, this has no relevance for stable.


> Signed-off-by: Julian Wiedmann <jwi@xxxxxxxxxxxxx>
> Reference-ID: JUP 394553
> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> ---
> drivers/s390/net/qeth_core.h | 5 -----
> drivers/s390/net/qeth_l3_main.c | 5 +++++
> 2 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/s390/net/qeth_core.h b/drivers/s390/net/qeth_core.h
> index b2657582cfcfd..41a2f901ccee5 100644
> --- a/drivers/s390/net/qeth_core.h
> +++ b/drivers/s390/net/qeth_core.h
> @@ -902,11 +902,6 @@ static inline void qeth_tx_csum(struct sk_buff *skb, u8 *flags, int ipv)
> if ((ipv == 4 && ip_hdr(skb)->protocol == IPPROTO_UDP) ||
> (ipv == 6 && ipv6_hdr(skb)->nexthdr == IPPROTO_UDP))
> *flags |= QETH_HDR_EXT_UDP;
> - if (ipv == 4) {
> - /* some HW requires combined L3+L4 csum offload: */
> - *flags |= QETH_HDR_EXT_CSUM_HDR_REQ;
> - ip_hdr(skb)->check = 0;
> - }
> }
>
> static inline void qeth_put_buffer_pool_entry(struct qeth_card *card,
> diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c
> index 9c5e801b3f6cb..c60660cb5a031 100644
> --- a/drivers/s390/net/qeth_l3_main.c
> +++ b/drivers/s390/net/qeth_l3_main.c
> @@ -2054,6 +2054,11 @@ static void qeth_l3_fill_header(struct qeth_card *card, struct qeth_hdr *hdr,
>
> if (!skb_is_gso(skb) && skb->ip_summed == CHECKSUM_PARTIAL) {
> qeth_tx_csum(skb, &hdr->hdr.l3.ext_flags, ipv);
> + /* some HW requires combined L3+L4 csum offload: */
> + if (ipv == 4) {
> + hdr->hdr.l3.ext_flags |= QETH_HDR_EXT_CSUM_HDR_REQ;
> + ip_hdr(skb)->check = 0;
> + }
> if (card->options.performance_stats)
> card->perf_stats.tx_csum++;
> }
>