From 1dfd2c79ec99679fa8c03164449c26081d95e6ec Mon Sep 17 00:00:00 2001
From: mbuhl <mbuhl@openbsd.org>
Date: Fri, 11 Nov 2022 16:41:44 +0000
Subject: [PATCH] Due to checksum offloading one more element could be written
 to the ring than there is space available. ok dlg

---
 sys/dev/pci/if_igc.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/sys/dev/pci/if_igc.c b/sys/dev/pci/if_igc.c
index 734bc8b0275..a904d43c66b 100644
--- a/sys/dev/pci/if_igc.c
+++ b/sys/dev/pci/if_igc.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_igc.c,v 1.9 2022/06/02 07:41:17 mbuhl Exp $	*/
+/*	$OpenBSD: if_igc.c,v 1.10 2022/11/11 16:41:44 mbuhl Exp $	*/
 /*-
  * SPDX-License-Identifier: BSD-2-Clause
  *
@@ -978,7 +978,7 @@ igc_start(struct ifqueue *ifq)
 	mask = sc->num_tx_desc - 1;
 
 	for (;;) {
-		if (free <= IGC_MAX_SCATTER) {
+		if (free <= IGC_MAX_SCATTER + 1) {
 			ifq_set_oactive(ifq);
 			break;
 		}
@@ -1005,6 +1005,7 @@ igc_start(struct ifqueue *ifq)
 			/* Consume the first descriptor */
 			prod++;
 			prod &= mask;
+			free--;
 		}
 
 		for (i = 0; i < map->dm_nsegs; i++) {
-- 
2.20.1