amd-xgbe: Remove need for Tx path spinlock
Since the Tx ring cleanup can run at the same time that data is being
transmitted, a spin lock was used to protect the ring. This patch
eliminates the need for Tx spinlocks by updating the current ring
position only after all ownership bits for data being transmitted have
been set. This will insure that ring operations in the Tx cleanup path
do not interfere with the ring operations in the Tx transmit path.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c b/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
index e2f560f..c036a0e 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-drv.c
@@ -415,17 +415,13 @@
struct xgbe_channel *channel = container_of(timer,
struct xgbe_channel,
tx_timer);
- struct xgbe_ring *ring = channel->tx_ring;
struct xgbe_prv_data *pdata = channel->pdata;
struct napi_struct *napi;
- unsigned long flags;
DBGPR("-->xgbe_tx_timer\n");
napi = (pdata->per_channel_irq) ? &channel->napi : &pdata->napi;
- spin_lock_irqsave(&ring->lock, flags);
-
if (napi_schedule_prep(napi)) {
/* Disable Tx and Rx interrupts */
if (pdata->per_channel_irq)
@@ -439,8 +435,6 @@
channel->tx_timer_active = 0;
- spin_unlock_irqrestore(&ring->lock, flags);
-
DBGPR("<--xgbe_tx_timer\n");
return HRTIMER_NORESTART;
@@ -1450,7 +1444,6 @@
struct xgbe_ring *ring;
struct xgbe_packet_data *packet;
struct netdev_queue *txq;
- unsigned long flags;
int ret;
DBGPR("-->xgbe_xmit: skb->len = %d\n", skb->len);
@@ -1462,8 +1455,6 @@
ret = NETDEV_TX_OK;
- spin_lock_irqsave(&ring->lock, flags);
-
if (skb->len == 0) {
netdev_err(netdev, "empty skb received from stack\n");
dev_kfree_skb_any(skb);
@@ -1510,10 +1501,6 @@
ret = NETDEV_TX_OK;
tx_netdev_return:
- spin_unlock_irqrestore(&ring->lock, flags);
-
- DBGPR("<--xgbe_xmit\n");
-
return ret;
}
@@ -1841,7 +1828,6 @@
struct xgbe_ring_desc *rdesc;
struct net_device *netdev = pdata->netdev;
struct netdev_queue *txq;
- unsigned long flags;
int processed = 0;
unsigned int tx_packets = 0, tx_bytes = 0;
@@ -1853,8 +1839,6 @@
txq = netdev_get_tx_queue(netdev, channel->queue_index);
- spin_lock_irqsave(&ring->lock, flags);
-
while ((processed < XGBE_TX_DESC_MAX_PROC) &&
(ring->dirty != ring->cur)) {
rdata = XGBE_GET_DESC_DATA(ring, ring->dirty);
@@ -1885,7 +1869,7 @@
}
if (!processed)
- goto unlock;
+ return 0;
netdev_tx_completed_queue(txq, tx_packets, tx_bytes);
@@ -1897,9 +1881,6 @@
DBGPR("<--xgbe_tx_poll: processed=%d\n", processed);
-unlock:
- spin_unlock_irqrestore(&ring->lock, flags);
-
return processed;
}