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authorYevgeny Petrilin <yevgenyp@mellanox.co.il>2012-08-03 04:38:37 +0400
committerDavid S. Miller <davem@davemloft.net>2012-08-04 03:49:02 +0400
commitc18520bd1b244fe8e3ac5358137321780a70d6e7 (patch)
tree99610de8cfed12e7be3ad2b7f03996e66b7ca8a0 /drivers/net/ethernet
parentc8c40b7f32abe0878ee693480fb2f7453d80add5 (diff)
downloadlinux-c18520bd1b244fe8e3ac5358137321780a70d6e7.tar.xz
net/mlx4_en: Fixing TX queue stop/wake flow
Removing the ring->blocked flag, it is redundant and leads to a race: We close the TX queue and then set the "blocked" flag. Between those 2 operations the completion function can check the "blocked" flag, sees that it is 0, and wouldn't open the TX queue. Using netif_tx_queue_stopped to check the state of the queue to avoid this race. Signed-off-by: Yevgeny Petrilin <yevgenyp@mellanox.co.il> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet')
-rw-r--r--drivers/net/ethernet/mellanox/mlx4/en_tx.c17
-rw-r--r--drivers/net/ethernet/mellanox/mlx4/mlx4_en.h1
2 files changed, 7 insertions, 11 deletions
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index 019d856b1334..10bba09c44ea 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -164,7 +164,6 @@ int mlx4_en_activate_tx_ring(struct mlx4_en_priv *priv,
ring->cons = 0xffffffff;
ring->last_nr_txbb = 1;
ring->poll_cnt = 0;
- ring->blocked = 0;
memset(ring->tx_info, 0, ring->size * sizeof(struct mlx4_en_tx_info));
memset(ring->buf, 0, ring->buf_size);
@@ -365,14 +364,13 @@ static void mlx4_en_process_tx_cq(struct net_device *dev, struct mlx4_en_cq *cq)
ring->cons += txbbs_skipped;
netdev_tx_completed_queue(ring->tx_queue, packets, bytes);
- /* Wakeup Tx queue if this ring stopped it */
- if (unlikely(ring->blocked)) {
- if ((u32) (ring->prod - ring->cons) <=
- ring->size - HEADROOM - MAX_DESC_TXBBS) {
- ring->blocked = 0;
- netif_tx_wake_queue(ring->tx_queue);
- priv->port_stats.wake_queue++;
- }
+ /*
+ * Wakeup Tx queue if this stopped, and at least 1 packet
+ * was completed
+ */
+ if (netif_tx_queue_stopped(ring->tx_queue) && txbbs_skipped > 0) {
+ netif_tx_wake_queue(ring->tx_queue);
+ priv->port_stats.wake_queue++;
}
}
@@ -592,7 +590,6 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
ring->size - HEADROOM - MAX_DESC_TXBBS)) {
/* every full Tx ring stops queue */
netif_tx_stop_queue(ring->tx_queue);
- ring->blocked = 1;
priv->port_stats.queue_stopped++;
return NETDEV_TX_BUSY;
diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
index 5f1ab105debc..9d27e42264e2 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
@@ -248,7 +248,6 @@ struct mlx4_en_tx_ring {
u32 doorbell_qpn;
void *buf;
u16 poll_cnt;
- int blocked;
struct mlx4_en_tx_info *tx_info;
u8 *bounce_buf;
u32 last_nr_txbb;