sfc: push partner queue for skb->xmit_more

Orabug: 22623841

[ Upstream commit b2663a4f30e85ec606b806f5135413e6d5c78d1e ]

When the IP stack passes SKBs the sfc driver puts them in 2 different TX
queues (called partners), one for checksummed and one for not checksummed.
If the SKB has xmit_more set the driver will delay pushing the work to the
NIC.

When later it does decide to push the buffers this patch ensures it also
pushes the partner queue, if that also has any delayed work. Before this
fix the work in the partner queue would be left for a long time and cause
a netdev watchdog.

Fixes: 70b33fb ("sfc: add support for skb->xmit_more")
Reported-by: Jianlin Shi <jishi@redhat.com>
Signed-off-by: Martin Habets <mhabets@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 20975f42a7933b489c0ef463e913c9742cfe2235)
Signed-off-by: Dan Duval <dan.duval@oracle.com>

diff --git a/drivers/net/ethernet/sfc/ef10.c b/drivers/net/ethernet/sfc/ef10.c
index fbb6cfa0f5f1d634c22eee11d3d62ca52bfef96e..feca46efa12f83059d2ac3ff1d63acd1b06615bb 100644 (file)
--- a/drivers/net/ethernet/sfc/ef10.c
+++ b/drivers/net/ethernet/sfc/ef10.c
@@ -1344,7 +1344,9 @@ static void efx_ef10_tx_write(struct efx_tx_queue *tx_queue)
        unsigned int write_ptr;
        efx_qword_t *txd;
 
-       BUG_ON(tx_queue->write_count == tx_queue->insert_count);
+       tx_queue->xmit_more_available = false;
+       if (unlikely(tx_queue->write_count == tx_queue->insert_count))
+               return;
 
        do {
                write_ptr = tx_queue->write_count & tx_queue->ptr_mask;

diff --git a/drivers/net/ethernet/sfc/farch.c b/drivers/net/ethernet/sfc/farch.c
index bb89e96a125eab7bf0e5d8569f6119adb720dbb5..6d4e0047a31d528cf11a06dec682ce63cfe428c0 100644 (file)
--- a/drivers/net/ethernet/sfc/farch.c
+++ b/drivers/net/ethernet/sfc/farch.c
@@ -319,7 +319,9 @@ void efx_farch_tx_write(struct efx_tx_queue *tx_queue)
        unsigned write_ptr;
        unsigned old_write_count = tx_queue->write_count;
 
-       BUG_ON(tx_queue->write_count == tx_queue->insert_count);
+       tx_queue->xmit_more_available = false;
+       if (unlikely(tx_queue->write_count == tx_queue->insert_count))
+               return;
 
        do {
                write_ptr = tx_queue->write_count & tx_queue->ptr_mask;

diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h
index 325dd94bca465ef99efe00b9d829b63c1abab3a0..0bdef4a074dd316c4abee8d53dd9084c7e6939d7 100644 (file)
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -218,6 +218,7 @@ struct efx_tx_buffer {
  * @tso_packets: Number of packets via the TSO xmit path
  * @pushes: Number of times the TX push feature has been used
  * @pio_packets: Number of times the TX PIO feature has been used
+ * @xmit_more_available: Are any packets waiting to be pushed to the NIC
  * @empty_read_count: If the completion path has seen the queue as empty
  *     and the transmission path has not yet checked this, the value of
  *     @read_count bitwise-added to %EFX_EMPTY_COUNT_VALID; otherwise 0.
@@ -250,6 +251,7 @@ struct efx_tx_queue {
        unsigned int tso_packets;
        unsigned int pushes;
        unsigned int pio_packets;
+       bool xmit_more_available;
        /* Statistics to supplement MAC stats */
        unsigned long tx_packets;
 

diff --git a/drivers/net/ethernet/sfc/tx.c b/drivers/net/ethernet/sfc/tx.c
index aaf2987512b5db7472bdef518c4aa4c510612ef7..e70edc3dea7e083f84142210f8b834e200e45b72 100644 (file)
--- a/drivers/net/ethernet/sfc/tx.c
+++ b/drivers/net/ethernet/sfc/tx.c
@@ -431,8 +431,20 @@ finish_packet:
        efx_tx_maybe_stop_queue(tx_queue);
 
        /* Pass off to hardware */
-       if (!skb->xmit_more || netif_xmit_stopped(tx_queue->core_txq))
+       if (!skb->xmit_more || netif_xmit_stopped(tx_queue->core_txq)) {
+               struct efx_tx_queue *txq2 = efx_tx_queue_partner(tx_queue);
+
+               /* There could be packets left on the partner queue if those
+                * SKBs had skb->xmit_more set. If we do not push those they
+                * could be left for a long time and cause a netdev watchdog.
+                */
+               if (txq2->xmit_more_available)
+                       efx_nic_push_buffers(txq2);
+
                efx_nic_push_buffers(tx_queue);
+       } else {
+               tx_queue->xmit_more_available = skb->xmit_more;
+       }
 
        tx_queue->tx_packets++;
 
@@ -721,6 +733,7 @@ void efx_init_tx_queue(struct efx_tx_queue *tx_queue)
        tx_queue->read_count = 0;
        tx_queue->old_read_count = 0;
        tx_queue->empty_read_count = 0 | EFX_EMPTY_COUNT_VALID;
+       tx_queue->xmit_more_available = false;
 
        /* Set up TX descriptor ring */
        efx_nic_init_tx(tx_queue);
@@ -746,6 +759,7 @@ void efx_fini_tx_queue(struct efx_tx_queue *tx_queue)
 
                ++tx_queue->read_count;
        }
+       tx_queue->xmit_more_available = false;
        netdev_tx_reset_queue(tx_queue->core_txq);
 }
 
@@ -1301,8 +1315,20 @@ static int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue,
        efx_tx_maybe_stop_queue(tx_queue);
 
        /* Pass off to hardware */
-       if (!skb->xmit_more || netif_xmit_stopped(tx_queue->core_txq))
+       if (!skb->xmit_more || netif_xmit_stopped(tx_queue->core_txq)) {
+               struct efx_tx_queue *txq2 = efx_tx_queue_partner(tx_queue);
+
+               /* There could be packets left on the partner queue if those
+                * SKBs had skb->xmit_more set. If we do not push those they
+                * could be left for a long time and cause a netdev watchdog.
+                */
+               if (txq2->xmit_more_available)
+                       efx_nic_push_buffers(txq2);
+
                efx_nic_push_buffers(tx_queue);
+       } else {
+               tx_queue->xmit_more_available = skb->xmit_more;
+       }
 
        tx_queue->tso_bursts++;
        return NETDEV_TX_OK;