net: systemport: Decouple flow control from __bcm_sysport_tx_reclaim

[ Upstream commit 148d3d021cf9724fcf189ce4e525a094bbf5ce89 ]

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/ethernet/broadcom/bcmsysport.c b/drivers/net/ethernet/broadcom/bcmsysport.c
index 858106352ce9c5bad35da49ed2d5d41c16cda144..8860e74aa28f6cfaee0a514aa567199cd293ee2a 100644 (file)
--- a/drivers/net/ethernet/broadcom/bcmsysport.c
+++ b/drivers/net/ethernet/broadcom/bcmsysport.c
@@ -732,11 +732,8 @@ static unsigned int __bcm_sysport_tx_reclaim(struct bcm_sysport_priv *priv,
        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;
@@ -767,9 +764,6 @@ static unsigned int __bcm_sysport_tx_reclaim(struct bcm_sysport_priv *priv,
 
        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);
@@ -781,16 +775,33 @@ static unsigned int __bcm_sysport_tx_reclaim(struct bcm_sysport_priv *priv,
 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 =
@@ -1275,7 +1286,7 @@ static void bcm_sysport_fini_tx_ring(struct bcm_sysport_priv *priv,
        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;