[PATCH 3.16 223/370] net: systemport: Decouple flow control from __bcm_sysport_tx_reclaim

Ben Hutchings
2017-03-10T12:43:18Z

From: Florian Fainelli <f.fainelli@gmail.com>

commit 148d3d021cf9724fcf189ce4e525a094bbf5ce89 upstream.

The __bcm_sysport_tx_reclaim() function is used to reclaim transmit
resources in different places within the driver. Most of them should
not affect the state of the transit flow control.

Introduce bcm_sysport_tx_clean() which cleans the ring, but does not
re-enable flow control towards the networking stack, and make
bcm_sysport_tx_reclaim() do the actual transmit queue flow control.

Fixes: 80105befdb4b ("net: systemport: add Broadcom SYSTEMPORT Ethernet MAC driver")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/net/ethernet/broadcom/bcmsysport.c | 25 ++++++++++++++++++-------
1 file changed, 18 insertions(+), 7 deletions(-)

--- a/drivers/net/ethernet/broadcom/bcmsysport.c
+++ b/drivers/net/ethernet/broadcom/bcmsysport.c
@@ -587,11 +587,8 @@ static unsigned int __bcm_sysport_tx_rec
unsigned int c_index, last_c_index, last_tx_cn, num_tx_cbs;
unsigned int pkts_compl = 0, bytes_compl = 0;
struct bcm_sysport_cb *cb;
- struct netdev_queue *txq;
u32 hw_ind;

- txq = netdev_get_tx_queue(ndev, ring->index);
-
/* Compute how many descriptors have been processed since last call */
hw_ind = tdma_readl(priv, TDMA_DESC_RING_PROD_CONS_INDEX(ring->index));
c_index = (hw_ind >> RING_CONS_INDEX_SHIFT) & RING_CONS_INDEX_MASK;
@@ -622,9 +619,6 @@ static unsigned int __bcm_sysport_tx_rec

ring->c_index = c_index;

- if (netif_tx_queue_stopped(txq) && pkts_compl)
- netif_tx_wake_queue(txq);
-
netif_dbg(priv, tx_done, ndev,
"ring=%d c_index=%d pkts_compl=%d, bytes_compl=%d\n",
ring->index, ring->c_index, pkts_compl, bytes_compl);
@@ -636,16 +630,33 @@ static unsigned int __bcm_sysport_tx_rec
static unsigned int bcm_sysport_tx_reclaim(struct bcm_sysport_priv *priv,
struct bcm_sysport_tx_ring *ring)
{
+ struct netdev_queue *txq;
unsigned int released;
unsigned long flags;

+ txq = netdev_get_tx_queue(priv->netdev, ring->index);
+
spin_lock_irqsave(&ring->lock, flags);
released = __bcm_sysport_tx_reclaim(priv, ring);
+ if (released)
+ netif_tx_wake_queue(txq);
+
spin_unlock_irqrestore(&ring->lock, flags);

return released;
}

+/* Locked version of the per-ring TX reclaim, but does not wake the queue */
+static void bcm_sysport_tx_clean(struct bcm_sysport_priv *priv,
+ struct bcm_sysport_tx_ring *ring)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&ring->lock, flags);
+ __bcm_sysport_tx_reclaim(priv, ring);
+ spin_unlock_irqrestore(&ring->lock, flags);
+}
+
static int bcm_sysport_tx_poll(struct napi_struct *napi, int budget)
{
struct bcm_sysport_tx_ring *ring =
@@ -1072,7 +1083,7 @@ static void bcm_sysport_fini_tx_ring(str
napi_disable(&ring->napi);
netif_napi_del(&ring->napi);

- bcm_sysport_tx_reclaim(priv, ring);
+ bcm_sysport_tx_clean(priv, ring);

kfree(ring->cbs);
ring->cbs = NULL;