[PATCH] net: atl1c: fix soft lockup on out-of-range tpd_cons read

[PATCH] net: atl1c: fix soft lockup on out-of-range tpd_cons read

[Gajdos Tamás]

The hardware can report an out-of-range tpd_cons (seen as 0xffff)
while the PCIe link/MAC is resetting. An out-of-range value can
never be reached and the loop below would spin forever. To avoid
a soft lockup treat it as "nothing new to clean" instead.

Signed-off-by: Gajdos Tamás <tamas@rimpianto.com>
---
 drivers/net/ethernet/atheros/atl1c/atl1c_main.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/atheros/atl1c/atl1c_main.c b/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
index 7efa3fc257..e58f1d2c26 100644
--- a/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
+++ b/drivers/net/ethernet/atheros/atl1c/atl1c_main.c
@@ -1602,6 +1602,9 @@ static int atl1c_clean_tx(struct napi_struct *napi, int budget)
 	AT_READ_REGW(&adapter->hw, atl1c_qregs[tpd_ring->num].tpd_cons,
 		     &hw_next_to_clean);
 
+	if (unlikely(hw_next_to_clean >= tpd_ring->count))
+		hw_next_to_clean = next_to_clean;
+
 	while (next_to_clean != hw_next_to_clean) {
 		buffer_info = &tpd_ring->buffer_info[next_to_clean];
 		if (buffer_info->skb) {
-- 
2.53.0