4 files changed, 106 insertions, 66 deletions

diff --git a/drivers/staging/octeon/ethernet-defines.h b/drivers/staging/octeon/ethernet-defines.h
index 8f7374e7664..f13131b03c3 100644
--- a/drivers/staging/octeon/ethernet-defines.h
+++ b/drivers/staging/octeon/ethernet-defines.h
@@ -117,6 +117,8 @@
 
 /* Maximum number of packets to process per interrupt. */
 #define MAX_RX_PACKETS 120
+/* Maximum number of SKBs to try to free per xmit packet. */
+#define MAX_SKB_TO_FREE 10
 #define MAX_OUT_QUEUE_DEPTH 1000
 
 #ifndef CONFIG_SMP
diff --git a/drivers/staging/octeon/ethernet-tx.c b/drivers/staging/octeon/ethernet-tx.c
index bfd3dd2fcef..81a851390f1 100644
--- a/drivers/staging/octeon/ethernet-tx.c
+++ b/drivers/staging/octeon/ethernet-tx.c
@@ -47,6 +47,7 @@
 
 #include "ethernet-defines.h"
 #include "octeon-ethernet.h"
+#include "ethernet-tx.h"
 #include "ethernet-util.h"
 
 #include "cvmx-wqe.h"
@@ -82,8 +83,10 @@ int cvm_oct_xmit(struct sk_buff *skb, struct net_device *dev)
         uint64_t old_scratch2;
         int dropped;
         int qos;
+        int queue_it_up;
         struct octeon_ethernet *priv = netdev_priv(dev);
-        int32_t in_use;
+        int32_t skb_to_free;
+        int32_t undo;
         int32_t buffers_to_free;
 #if REUSE_SKBUFFS_WITHOUT_FREE
         unsigned char *fpa_head;
@@ -120,15 +123,15 @@ int cvm_oct_xmit(struct sk_buff *skb, struct net_device *dev)
                 old_scratch2 = cvmx_scratch_read64(CVMX_SCR_SCRATCH + 8);
 
                 /*
-                 * Assume we're going to be able t osend this
-                 * packet. Fetch and increment the number of pending
-                 * packets for output.
+                 * Fetch and increment the number of packets to be
+                 * freed.
                  */
                 cvmx_fau_async_fetch_and_add32(CVMX_SCR_SCRATCH + 8,
                                                FAU_NUM_PACKET_BUFFERS_TO_FREE,
                                                0);
                 cvmx_fau_async_fetch_and_add32(CVMX_SCR_SCRATCH,
-                                               priv->fau + qos * 4, 1);
+                                               priv->fau + qos * 4,
+                                               MAX_SKB_TO_FREE);
         }
 
         /*
@@ -286,16 +289,30 @@ dont_put_skbuff_in_hw:
         if (USE_ASYNC_IOBDMA) {
                 /* Get the number of skbuffs in use by the hardware */
                 CVMX_SYNCIOBDMA;
-                in_use = cvmx_scratch_read64(CVMX_SCR_SCRATCH);
+                skb_to_free = cvmx_scratch_read64(CVMX_SCR_SCRATCH);
                 buffers_to_free = cvmx_scratch_read64(CVMX_SCR_SCRATCH + 8);
         } else {
                 /* Get the number of skbuffs in use by the hardware */
-                in_use = cvmx_fau_fetch_and_add32(priv->fau + qos * 4, 1);
+                skb_to_free = cvmx_fau_fetch_and_add32(priv->fau + qos * 4,
+                                                       MAX_SKB_TO_FREE);
                 buffers_to_free =
                     cvmx_fau_fetch_and_add32(FAU_NUM_PACKET_BUFFERS_TO_FREE, 0);
         }
 
         /*
+         * We try to claim MAX_SKB_TO_FREE buffers.  If there were not
+         * that many available, we have to un-claim (undo) any that
+         * were in excess.  If skb_to_free is positive we will free
+         * that many buffers.
+         */
+        undo = skb_to_free > 0 ?
+                MAX_SKB_TO_FREE : skb_to_free + MAX_SKB_TO_FREE;
+        if (undo > 0)
+                cvmx_fau_atomic_add32(priv->fau+qos*4, -undo);
+        skb_to_free = -skb_to_free > MAX_SKB_TO_FREE ?
+                MAX_SKB_TO_FREE : -skb_to_free;
+
+        /*
          * If we're sending faster than the receive can free them then
          * don't do the HW free.
          */
@@ -330,38 +347,31 @@ dont_put_skbuff_in_hw:
                 cvmx_scratch_write64(CVMX_SCR_SCRATCH + 8, old_scratch2);
         }
 
+        queue_it_up = 0;
         if (unlikely(dropped)) {
                 dev_kfree_skb_any(skb);
-                cvmx_fau_atomic_add32(priv->fau + qos * 4, -1);
                 priv->stats.tx_dropped++;
         } else {
                 if (USE_SKBUFFS_IN_HW) {
                         /* Put this packet on the queue to be freed later */
                         if (pko_command.s.dontfree)
-                                skb_queue_tail(&priv->tx_free_list[qos], skb);
-                        else {
+                                queue_it_up = 1;
+                        else
                                 cvmx_fau_atomic_add32
                                     (FAU_NUM_PACKET_BUFFERS_TO_FREE, -1);
-                                cvmx_fau_atomic_add32(priv->fau + qos * 4, -1);
-                        }
                 } else {
                         /* Put this packet on the queue to be freed later */
-                        skb_queue_tail(&priv->tx_free_list[qos], skb);
+                        queue_it_up = 1;
                 }
         }
 
-        /* Free skbuffs not in use by the hardware, possibly two at a time */
-        if (skb_queue_len(&priv->tx_free_list[qos]) > in_use) {
+        if (queue_it_up) {
                 spin_lock(&priv->tx_free_list[qos].lock);
-                /*
-                 * Check again now that we have the lock. It might
-                 * have changed.
-                 */
-                if (skb_queue_len(&priv->tx_free_list[qos]) > in_use)
-                        dev_kfree_skb(__skb_dequeue(&priv->tx_free_list[qos]));
-                if (skb_queue_len(&priv->tx_free_list[qos]) > in_use)
-                        dev_kfree_skb(__skb_dequeue(&priv->tx_free_list[qos]));
+                __skb_queue_tail(&priv->tx_free_list[qos], skb);
+                cvm_oct_free_tx_skbs(priv, skb_to_free, qos, 0);
                 spin_unlock(&priv->tx_free_list[qos].lock);
+        } else {
+                cvm_oct_free_tx_skbs(priv, skb_to_free, qos, 1);
         }
 
         return 0;
diff --git a/drivers/staging/octeon/ethernet-tx.h b/drivers/staging/octeon/ethernet-tx.h
index 5106236fe98..c0bebf750bc 100644
--- a/drivers/staging/octeon/ethernet-tx.h
+++ b/drivers/staging/octeon/ethernet-tx.h
@@ -30,3 +30,28 @@ int cvm_oct_xmit_pow(struct sk_buff *skb, struct net_device *dev);
 int cvm_oct_transmit_qos(struct net_device *dev, void *work_queue_entry,
                          int do_free, int qos);
 void cvm_oct_tx_shutdown(struct net_device *dev);
+
+/**
+ * Free dead transmit skbs.
+ *
+ * @priv:               The driver data
+ * @skb_to_free:        The number of SKBs to free (free none if negative).
+ * @qos:                The queue to free from.
+ * @take_lock:          If true, acquire the skb list lock.
+ */
+static inline void cvm_oct_free_tx_skbs(struct octeon_ethernet *priv,
+                                        int skb_to_free,
+                                        int qos, int take_lock)
+{
+        /* Free skbuffs not in use by the hardware.  */
+        if (skb_to_free > 0) {
+                if (take_lock)
+                        spin_lock(&priv->tx_free_list[qos].lock);
+                while (skb_to_free > 0) {
+                        dev_kfree_skb(__skb_dequeue(&priv->tx_free_list[qos]));
+                        skb_to_free--;
+                }
+                if (take_lock)
+                        spin_unlock(&priv->tx_free_list[qos].lock);
+        }
+}
diff --git a/drivers/staging/octeon/ethernet.c b/drivers/staging/octeon/ethernet.c
index 2d9356dfbca..b8479517dce 100644
--- a/drivers/staging/octeon/ethernet.c
+++ b/drivers/staging/octeon/ethernet.c
@@ -37,13 +37,14 @@
 #include <asm/octeon/octeon.h>
 
 #include "ethernet-defines.h"
+#include "octeon-ethernet.h"
 #include "ethernet-mem.h"
 #include "ethernet-rx.h"
 #include "ethernet-tx.h"
 #include "ethernet-mdio.h"
 #include "ethernet-util.h"
 #include "ethernet-proc.h"
-#include "octeon-ethernet.h"
+
 
 #include "cvmx-pip.h"
 #include "cvmx-pko.h"
@@ -130,53 +131,55 @@ extern struct semaphore mdio_sem;
  */
 static void cvm_do_timer(unsigned long arg)
 {
+        int32_t skb_to_free, undo;
+        int queues_per_port;
+        int qos;
+        struct octeon_ethernet *priv;
         static int port;
-        if (port < CVMX_PIP_NUM_INPUT_PORTS) {
-                if (cvm_oct_device[port]) {
-                        int queues_per_port;
-                        int qos;
-                        struct octeon_ethernet *priv =
-                                netdev_priv(cvm_oct_device[port]);
-                        if (priv->poll) {
-                                /* skip polling if we don't get the lock */
-                                if (!down_trylock(&mdio_sem)) {
-                                        priv->poll(cvm_oct_device[port]);
-                                        up(&mdio_sem);
-                                }
-                        }
 
-                        queues_per_port = cvmx_pko_get_num_queues(port);
-                        /* Drain any pending packets in the free list */
-                        for (qos = 0; qos < queues_per_port; qos++) {
-                                if (skb_queue_len(&priv->tx_free_list[qos])) {
-                                        spin_lock(&priv->tx_free_list[qos].
-                                                  lock);
-                                        while (skb_queue_len
-                                               (&priv->tx_free_list[qos]) >
-                                               cvmx_fau_fetch_and_add32(priv->
-                                                                        fau +
-                                                                        qos * 4,
-                                                                        0))
-                                                dev_kfree_skb(__skb_dequeue
-                                                              (&priv->
-                                                               tx_free_list
-                                                               [qos]));
-                                        spin_unlock(&priv->tx_free_list[qos].
-                                                    lock);
-                                }
-                        }
-                        cvm_oct_device[port]->netdev_ops->ndo_get_stats(cvm_oct_device[port]);
-                }
-                port++;
-                /* Poll the next port in a 50th of a second.
-                   This spreads the polling of ports out a little bit */
-                mod_timer(&cvm_oct_poll_timer, jiffies + HZ / 50);
-        } else {
+        if (port >= CVMX_PIP_NUM_INPUT_PORTS) {
+                /*
+                 * All ports have been polled. Start the next
+                 * iteration through the ports in one second.
+                 */
                 port = 0;
-                /* All ports have been polled. Start the next iteration through
-                   the ports in one second */
                 mod_timer(&cvm_oct_poll_timer, jiffies + HZ);
+                return;
+        }
+        if (!cvm_oct_device[port])
+                goto out;
+
+        priv = netdev_priv(cvm_oct_device[port]);
+        if (priv->poll) {
+                /* skip polling if we don't get the lock */
+                if (!down_trylock(&mdio_sem)) {
+                        priv->poll(cvm_oct_device[port]);
+                        up(&mdio_sem);
+                }
+        }
+
+        queues_per_port = cvmx_pko_get_num_queues(port);
+        /* Drain any pending packets in the free list */
+        for (qos = 0; qos < queues_per_port; qos++) {
+                if (skb_queue_len(&priv->tx_free_list[qos]) == 0)
+                        continue;
+                skb_to_free = cvmx_fau_fetch_and_add32(priv->fau + qos * 4,
+                                                       MAX_SKB_TO_FREE);
+                undo = skb_to_free > 0 ?
+                        MAX_SKB_TO_FREE : skb_to_free + MAX_SKB_TO_FREE;
+                if (undo > 0)
+                        cvmx_fau_atomic_add32(priv->fau+qos*4, -undo);
+                skb_to_free = -skb_to_free > MAX_SKB_TO_FREE ?
+                        MAX_SKB_TO_FREE : -skb_to_free;
+                cvm_oct_free_tx_skbs(priv, skb_to_free, qos, 1);
         }
+        cvm_oct_device[port]->netdev_ops->ndo_get_stats(cvm_oct_device[port]);
+
+out:
+        port++;
+        /* Poll the next port in a 50th of a second.
+           This spreads the polling of ports out a little bit */
+        mod_timer(&cvm_oct_poll_timer, jiffies + HZ / 50);
 }
 
 /**