From 2367a17390138f68b3aa28f2f220b8d7ff8d91f4 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Tue, 26 Aug 2014 19:34:18 +0200 Subject: [PATCH] ixgbe: flush when in xmit_more mode and under descriptor pressure When xmit_more mode is being used and the ring is about to become full or the stack has stopped the ring, enforce a tail pointer write to the hw. Otherwise, we could risk a TX hang. Code suggested by Alexander Duyck. Signed-off-by: Alexander Duyck Signed-off-by: Daniel Borkmann Signed-off-by: David S. Miller --- drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 63 +++++++++++++++------------ 1 file changed, 34 insertions(+), 29 deletions(-) diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c index ba9ceaa..53fbf06 100644 --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c @@ -6837,6 +6837,36 @@ static void ixgbe_tx_olinfo_status(union ixgbe_adv_tx_desc *tx_desc, tx_desc->read.olinfo_status = cpu_to_le32(olinfo_status); } +static int __ixgbe_maybe_stop_tx(struct ixgbe_ring *tx_ring, u16 size) +{ + netif_stop_subqueue(tx_ring->netdev, tx_ring->queue_index); + + /* 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(ixgbe_desc_unused(tx_ring) < size)) + return -EBUSY; + + /* A reprieve! - use start_queue because it doesn't call schedule */ + netif_start_subqueue(tx_ring->netdev, tx_ring->queue_index); + ++tx_ring->tx_stats.restart_queue; + return 0; +} + +static inline int ixgbe_maybe_stop_tx(struct ixgbe_ring *tx_ring, u16 size) +{ + if (likely(ixgbe_desc_unused(tx_ring) >= size)) + return 0; + + return __ixgbe_maybe_stop_tx(tx_ring, size); +} + #define IXGBE_TXD_CMD (IXGBE_TXD_CMD_EOP | \ IXGBE_TXD_CMD_RS) @@ -6958,10 +6988,13 @@ static void ixgbe_tx_map(struct ixgbe_ring *tx_ring, tx_ring->next_to_use = i; - if (!skb->xmit_more) { + ixgbe_maybe_stop_tx(tx_ring, DESC_NEEDED); + + if (netif_xmit_stopped(txring_txq(tx_ring)) || !skb->xmit_more) { /* notify HW of packet */ ixgbe_write_tail(tx_ring, i); } + return; dma_error: dev_err(tx_ring->dev, "TX DMA map failed\n"); @@ -7068,32 +7101,6 @@ static void ixgbe_atr(struct ixgbe_ring *ring, input, common, ring->queue_index); } -static int __ixgbe_maybe_stop_tx(struct ixgbe_ring *tx_ring, u16 size) -{ - netif_stop_subqueue(tx_ring->netdev, tx_ring->queue_index); - /* 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(ixgbe_desc_unused(tx_ring) < size)) - return -EBUSY; - - /* A reprieve! - use start_queue because it doesn't call schedule */ - netif_start_subqueue(tx_ring->netdev, tx_ring->queue_index); - ++tx_ring->tx_stats.restart_queue; - return 0; -} - -static inline int ixgbe_maybe_stop_tx(struct ixgbe_ring *tx_ring, u16 size) -{ - if (likely(ixgbe_desc_unused(tx_ring) >= size)) - return 0; - return __ixgbe_maybe_stop_tx(tx_ring, size); -} - static u16 ixgbe_select_queue(struct net_device *dev, struct sk_buff *skb, void *accel_priv, select_queue_fallback_t fallback) { @@ -7262,8 +7269,6 @@ xmit_fcoe: #endif /* IXGBE_FCOE */ ixgbe_tx_map(tx_ring, first, hdr_len); - ixgbe_maybe_stop_tx(tx_ring, DESC_NEEDED); - return NETDEV_TX_OK; out_drop: -- 2.7.4