net: mvpp2: fix a txq_done race condition

[ Upstream commit 774268f3e51b53ed432a1ec516574fd5ba469398 ]

When no Tx IRQ is available, the txq_done() routine (called from
tx_done()) shouldn't be called from the polling function, as in such
case it is already called in the Tx path thanks to an hrtimer. This
mostly occurred when using PPv2.1, as the engine then do not have Tx
IRQs.

Fixes: edc660fa09e2 ("net: mvpp2: replace TX coalescing interrupts with hrtimer")
Reported-by: Stefan Chulski <stefanc@marvell.com>
Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/ethernet/marvell/mvpp2.c b/drivers/net/ethernet/marvell/mvpp2.c
index c5e9a897fbdf9dc4ea9399fd1ab456a7e601c97b..00e6f1d155a6ffc00a4897ff3a9a02741520c576 100644 (file)
--- a/drivers/net/ethernet/marvell/mvpp2.c
+++ b/drivers/net/ethernet/marvell/mvpp2.c
@@ -6534,10 +6534,12 @@ static int mvpp2_poll(struct napi_struct *napi, int budget)
                                   cause_rx_tx & ~MVPP2_CAUSE_MISC_SUM_MASK);
        }
 
-       cause_tx = cause_rx_tx & MVPP2_CAUSE_TXQ_OCCUP_DESC_ALL_MASK;
-       if (cause_tx) {
-               cause_tx >>= MVPP2_CAUSE_TXQ_OCCUP_DESC_ALL_OFFSET;
-               mvpp2_tx_done(port, cause_tx, qv->sw_thread_id);
+       if (port->has_tx_irqs) {
+               cause_tx = cause_rx_tx & MVPP2_CAUSE_TXQ_OCCUP_DESC_ALL_MASK;
+               if (cause_tx) {
+                       cause_tx >>= MVPP2_CAUSE_TXQ_OCCUP_DESC_ALL_OFFSET;
+                       mvpp2_tx_done(port, cause_tx, qv->sw_thread_id);
+               }
        }
 
        /* Process RX packets */