[PATCH net-next 04/13] bnxt_en: Prevent TX timeout with a very small TX ring

[Michael Chan <michael.chan@broadcom.com>]

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If xmit_more condition is true, the driver may set the
TX_BD_FLAGS_NO_CMPL flag.  If after this packet, the TX ring can no
longer hold a packet with maximum fragments, we will stop the TX
queue.  When this happens, we must clear the TX_BD_FLAGS_NO_CMPL flag
on the last packet or there will be no completion and cause TX
timeout.

Fixes: c1056a59aee1 ("bnxt_en: Optimize xmit_more TX path")
Reviewed-by: Somnath Kotur <somnath.kotur@broadcom.com>
Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
Reviewed-by: Hongguang Gao <hongguang.gao@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
---
 drivers/net/ethernet/broadcom/bnxt/bnxt.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index 83a47feaf869..cc6cab340423 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -666,8 +666,11 @@ static netdev_tx_t bnxt_start_xmit(struct sk_buff *skb, struct net_device *dev)
 tx_done:
 
 	if (unlikely(bnxt_tx_avail(bp, txr) <= MAX_SKB_FRAGS + 1)) {
-		if (netdev_xmit_more() && !tx_buf->is_push)
+		if (netdev_xmit_more() && !tx_buf->is_push) {
+			txbd0->tx_bd_len_flags_type &=
+				cpu_to_le32(~TX_BD_FLAGS_NO_CMPL);
 			bnxt_txr_db_kick(bp, txr, prod);
+		}
 
 		netif_txq_try_stop(txq, bnxt_tx_avail(bp, txr),
 				   bp->tx_wake_thresh);
-- 
2.30.1


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