From: Julian Wiedmann <jwi@linux.ibm.com>
Subject: s390/qeth: try harder to get packets from RX buffer
Patch-mainline: v4.15-rc1
Git-commit: 864c17c3d83be6a1f6a2888566e93e114986abca
References: FATE#326350, LTC#169511, bsc#1113509
Summary: qeth: performance improvements
Description: This adds recent functional and performance improvements for the
qeth network driver.
Primarily this brings Scatter-Gather support for HiperSockets,
reduced CPU consumption in the L3 IPv4 transmit path for OSA,
improved Promiscuous Mode performance due to IFF_UNICAST_FLT,
support for Scatter-Gather on z/VM virtual NICs, and
support for delayed GRO flushing.
For sanity & stability reasons, this effectively constitutes a
backport of the qeth device driver from 4.19 mainline.
Upstream-Description:
s390/qeth: try harder to get packets from RX buffer
Current code bails out when two subsequent buffer elements hold
insufficient data to contain a qeth_hdr packet descriptor.
This seems reasonable, but it would be legal for quirky hardware to
leave a few elements empty and then present packets in a subsequent
element. These packets would currently be dropped.
So make sure to check all buffer elements, until we hit the LAST_ENTRY
indication.
Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
drivers/s390/net/qeth_core_main.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -5231,13 +5231,11 @@ struct sk_buff *qeth_core_get_next_skb(s
int use_rx_sg = 0;
/* qeth_hdr must not cross element boundaries */
- if (element->length < offset + sizeof(struct qeth_hdr)) {
+ while (element->length < offset + sizeof(struct qeth_hdr)) {
if (qeth_is_last_sbale(element))
return NULL;
element++;
offset = 0;
- if (element->length < sizeof(struct qeth_hdr))
- return NULL;
}
*hdr = element->addr + offset;