[PATCH 5.5 125/176] s390/qeth: fix off-by-one in RX copybreak check

From: Greg Kroah-Hartman
Date: Tue Mar 03 2020 - 13:11:44 EST


From: Julian Wiedmann <jwi@xxxxxxxxxxxxx>

commit 54a61fbc020fd2e305680871c453abcf7fc0339b upstream.

The RX copybreak is intended as the _max_ value where the frame's data
should be copied. So for frame_len == copybreak, don't build an SG skb.

Fixes: 4a71df50047f ("qeth: new qeth device driver")
Signed-off-by: Julian Wiedmann <jwi@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/s390/net/qeth_core_main.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -5142,7 +5142,7 @@ next_packet:
}

use_rx_sg = (card->options.cq == QETH_CQ_ENABLED) ||
- ((skb_len >= card->options.rx_sg_cb) &&
+ (skb_len > card->options.rx_sg_cb &&
!atomic_read(&card->force_alloc_skb) &&
!IS_OSN(card));