ixgb: Maybe stop TX if not enough free descriptors
A similar patch to commit 65c7973fa5b46b024f38be208aa477e8daf9a603
but now for ixgb.
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
diff --git a/drivers/net/ixgb/ixgb_main.c b/drivers/net/ixgb/ixgb_main.c
index 70ac9d4..16317b5 100644
--- a/drivers/net/ixgb/ixgb_main.c
+++ b/drivers/net/ixgb/ixgb_main.c
@@ -1411,6 +1411,37 @@
IXGB_WRITE_REG(&adapter->hw, TDT, i);
}
+static int __ixgb_maybe_stop_tx(struct net_device *netdev, int size)
+{
+ struct ixgb_adapter *adapter = netdev_priv(netdev);
+ struct ixgb_desc_ring *tx_ring = &adapter->tx_ring;
+
+ netif_stop_queue(netdev);
+ /* Herbert's original patch had:
+ * smp_mb__after_netif_stop_queue();
+ * but since that doesn't exist yet, just open code it. */
+ smp_mb();
+
+ /* We need to check again in a case another CPU has just
+ * made room available. */
+ if (likely(IXGB_DESC_UNUSED(tx_ring) < size))
+ return -EBUSY;
+
+ /* A reprieve! */
+ netif_start_queue(netdev);
+ ++adapter->restart_queue;
+ return 0;
+}
+
+static int ixgb_maybe_stop_tx(struct net_device *netdev,
+ struct ixgb_desc_ring *tx_ring, int size)
+{
+ if (likely(IXGB_DESC_UNUSED(tx_ring) >= size))
+ return 0;
+ return __ixgb_maybe_stop_tx(netdev, size);
+}
+
+
/* Tx Descriptors needed, worst case */
#define TXD_USE_COUNT(S) (((S) >> IXGB_MAX_TXD_PWR) + \
(((S) & (IXGB_MAX_DATA_PER_TXD - 1)) ? 1 : 0))
@@ -1444,7 +1475,8 @@
spin_lock_irqsave(&adapter->tx_lock, flags);
#endif
- if(unlikely(IXGB_DESC_UNUSED(&adapter->tx_ring) < DESC_NEEDED)) {
+ if (unlikely(ixgb_maybe_stop_tx(netdev, &adapter->tx_ring,
+ DESC_NEEDED))) {
netif_stop_queue(netdev);
spin_unlock_irqrestore(&adapter->tx_lock, flags);
return NETDEV_TX_BUSY;
@@ -1482,8 +1514,7 @@
#ifdef NETIF_F_LLTX
/* Make sure there is space in the ring for the next send. */
- if(unlikely(IXGB_DESC_UNUSED(&adapter->tx_ring) < DESC_NEEDED))
- netif_stop_queue(netdev);
+ ixgb_maybe_stop_tx(netdev, &adapter->tx_ring, DESC_NEEDED);
spin_unlock_irqrestore(&adapter->tx_lock, flags);