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-dev.c b/drivers/net/ethernet/amd/xgbe/xgbe-dev.c
index e424997..5dff127 100644
--- a/drivers/net/ethernet/amd/xgbe/xgbe-dev.c
+++ b/drivers/net/ethernet/amd/xgbe/xgbe-dev.c
@@ -1359,6 +1359,7 @@
unsigned int tso_context, vlan_context;
unsigned int tx_set_ic;
int start_index = ring->cur;
+ int cur_index = ring->cur;
int i;
DBGPR("-->xgbe_dev_xmit\n");
@@ -1401,7 +1402,7 @@
else
tx_set_ic = 0;
- rdata = XGBE_GET_DESC_DATA(ring, ring->cur);
+ rdata = XGBE_GET_DESC_DATA(ring, cur_index);
rdesc = rdata->rdesc;
/* Create a context descriptor if this is a TSO packet */
@@ -1444,8 +1445,8 @@
ring->tx.cur_vlan_ctag = packet->vlan_ctag;
}
- ring->cur++;
- rdata = XGBE_GET_DESC_DATA(ring, ring->cur);
+ cur_index++;
+ rdata = XGBE_GET_DESC_DATA(ring, cur_index);
rdesc = rdata->rdesc;
}
@@ -1473,7 +1474,7 @@
XGMAC_SET_BITS_LE(rdesc->desc3, TX_NORMAL_DESC3, CTXT, 0);
/* Set OWN bit if not the first descriptor */
- if (ring->cur != start_index)
+ if (cur_index != start_index)
XGMAC_SET_BITS_LE(rdesc->desc3, TX_NORMAL_DESC3, OWN, 1);
if (tso) {
@@ -1497,9 +1498,9 @@
packet->length);
}
- for (i = ring->cur - start_index + 1; i < packet->rdesc_count; i++) {
- ring->cur++;
- rdata = XGBE_GET_DESC_DATA(ring, ring->cur);
+ for (i = cur_index - start_index + 1; i < packet->rdesc_count; i++) {
+ cur_index++;
+ rdata = XGBE_GET_DESC_DATA(ring, cur_index);
rdesc = rdata->rdesc;
/* Update buffer address */
@@ -1551,7 +1552,7 @@
/* Make sure ownership is written to the descriptor */
wmb();
- ring->cur++;
+ ring->cur = cur_index + 1;
if (!packet->skb->xmit_more ||
netif_xmit_stopped(netdev_get_tx_queue(pdata->netdev,
channel->queue_index)))