[PATCH net-next 11/13] s390/qeth: try harder to get packets from RX buffer

Julian Wiedmann
2017-10-18T15:40:23Z

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>
---
drivers/s390/net/qeth_core_main.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 23b439fb5f2c..8855bc8534d2 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -5214,13 +5214,11 @@ struct sk_buff *qeth_core_get_next_skb(struct qeth_card *card,
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;

--
2.13.5