1 files changed, 63 insertions, 9 deletions

diff --git a/drivers/net/e100.c b/drivers/net/e100.c
index 61696637a21e..763810c7f33a 100644
--- a/drivers/net/e100.c
+++ b/drivers/net/e100.c
@@ -285,6 +285,12 @@ enum scb_status {
         rus_mask         = 0x3C,
 };
 
+enum ru_state  {
+        RU_SUSPENDED = 0,
+        RU_RUNNING       = 1,
+        RU_UNINITIALIZED = -1,
+};
+
 enum scb_stat_ack {
         stat_ack_not_ours    = 0x00,
         stat_ack_sw_gen      = 0x04,
@@ -526,6 +532,7 @@ struct nic {
         struct rx *rx_to_use;
         struct rx *rx_to_clean;
         struct rfd blank_rfd;
+        enum ru_state ru_running;
 
         spinlock_t cb_lock                      ____cacheline_aligned;
         spinlock_t cmd_lock;
@@ -947,7 +954,7 @@ static void e100_get_defaults(struct nic *nic)
                 ((nic->mac >= mac_82558_D101_A4) ? cb_cid : cb_i));
 
         /* Template for a freshly allocated RFD */
-        nic->blank_rfd.command = cpu_to_le16(cb_el & cb_s);
+        nic->blank_rfd.command = cpu_to_le16(cb_el);
         nic->blank_rfd.rbd = 0xFFFFFFFF;
         nic->blank_rfd.size = cpu_to_le16(VLAN_ETH_FRAME_LEN);
 
@@ -1742,11 +1749,19 @@ static int e100_alloc_cbs(struct nic *nic)
         return 0;
 }
 
-static inline void e100_start_receiver(struct nic *nic)
+static inline void e100_start_receiver(struct nic *nic, struct rx *rx)
 {
-        /* Start if RFA is non-NULL */
-        if(nic->rx_to_clean->skb)
-                e100_exec_cmd(nic, ruc_start, nic->rx_to_clean->dma_addr);
+        if(!nic->rxs) return;
+        if(RU_SUSPENDED != nic->ru_running) return;
+
+        /* handle init time starts */
+        if(!rx) rx = nic->rxs;
+
+        /* (Re)start RU if suspended or idle and RFA is non-NULL */
+        if(rx->skb) {
+                e100_exec_cmd(nic, ruc_start, rx->dma_addr);
+                nic->ru_running = RU_RUNNING;
+        }
 }
 
 #define RFD_BUF_LEN (sizeof(struct rfd) + VLAN_ETH_FRAME_LEN)
@@ -1775,7 +1790,7 @@ static int e100_rx_alloc_skb(struct nic *nic, struct rx *rx)
                 put_unaligned(cpu_to_le32(rx->dma_addr),
                         (u32 *)&prev_rfd->link);
                 wmb();
-                prev_rfd->command &= ~cpu_to_le16(cb_el & cb_s);
+                prev_rfd->command &= ~cpu_to_le16(cb_el);
                 pci_dma_sync_single_for_device(nic->pdev, rx->prev->dma_addr,
                         sizeof(struct rfd), PCI_DMA_TODEVICE);
         }
@@ -1813,6 +1828,10 @@ static int e100_rx_indicate(struct nic *nic, struct rx *rx,
         pci_unmap_single(nic->pdev, rx->dma_addr,
                 RFD_BUF_LEN, PCI_DMA_FROMDEVICE);
 
+        /* this allows for a fast restart without re-enabling interrupts */
+        if(le16_to_cpu(rfd->command) & cb_el)
+                nic->ru_running = RU_SUSPENDED;
+
         /* Pull off the RFD and put the actual data (minus eth hdr) */
         skb_reserve(skb, sizeof(struct rfd));
         skb_put(skb, actual_size);
@@ -1843,18 +1862,45 @@ static void e100_rx_clean(struct nic *nic, unsigned int *work_done,
         unsigned int work_to_do)
 {
         struct rx *rx;
+        int restart_required = 0;
+        struct rx *rx_to_start = NULL;
+
+        /* are we already rnr? then pay attention!!! this ensures that
+         * the state machine progression never allows a start with a
+         * partially cleaned list, avoiding a race between hardware
+         * and rx_to_clean when in NAPI mode */
+        if(RU_SUSPENDED == nic->ru_running)
+                restart_required = 1;
 
         /* Indicate newly arrived packets */
         for(rx = nic->rx_to_clean; rx->skb; rx = nic->rx_to_clean = rx->next) {
-                if(e100_rx_indicate(nic, rx, work_done, work_to_do))
+                int err = e100_rx_indicate(nic, rx, work_done, work_to_do);
+                if(-EAGAIN == err) {
+                        /* hit quota so have more work to do, restart once
+                         * cleanup is complete */
+                        restart_required = 0;
+                        break;
+                } else if(-ENODATA == err)
                         break; /* No more to clean */
         }
 
+        /* save our starting point as the place we'll restart the receiver */
+        if(restart_required)
+                rx_to_start = nic->rx_to_clean;
+
         /* Alloc new skbs to refill list */
         for(rx = nic->rx_to_use; !rx->skb; rx = nic->rx_to_use = rx->next) {
                 if(unlikely(e100_rx_alloc_skb(nic, rx)))
                         break; /* Better luck next time (see watchdog) */
         }
+
+        if(restart_required) {
+                // ack the rnr?
+                writeb(stat_ack_rnr, &nic->csr->scb.stat_ack);
+                e100_start_receiver(nic, rx_to_start);
+                if(work_done)
+                        (*work_done)++;
+        }
 }
 
 static void e100_rx_clean_list(struct nic *nic)
@@ -1862,6 +1908,8 @@ static void e100_rx_clean_list(struct nic *nic)
         struct rx *rx;
         unsigned int i, count = nic->params.rfds.count;
 
+        nic->ru_running = RU_UNINITIALIZED;
+
         if(nic->rxs) {
                 for(rx = nic->rxs, i = 0; i < count; rx++, i++) {
                         if(rx->skb) {
@@ -1883,6 +1931,7 @@ static int e100_rx_alloc_list(struct nic *nic)
         unsigned int i, count = nic->params.rfds.count;
 
         nic->rx_to_use = nic->rx_to_clean = NULL;
+        nic->ru_running = RU_UNINITIALIZED;
 
         if(!(nic->rxs = kcalloc(count, sizeof(struct rx), GFP_ATOMIC)))
                 return -ENOMEM;
@@ -1897,6 +1946,7 @@ static int e100_rx_alloc_list(struct nic *nic)
         }
 
         nic->rx_to_use = nic->rx_to_clean = nic->rxs;
+        nic->ru_running = RU_SUSPENDED;
 
         return 0;
 }
@@ -1916,6 +1966,10 @@ static irqreturn_t e100_intr(int irq, void *dev_id)
         /* Ack interrupt(s) */
         iowrite8(stat_ack, &nic->csr->scb.stat_ack);
 
+        /* We hit Receive No Resource (RNR); restart RU after cleaning */
+        if(stat_ack & stat_ack_rnr)
+                nic->ru_running = RU_SUSPENDED;
+
         if(likely(netif_rx_schedule_prep(netdev))) {
                 e100_disable_irq(nic);
                 __netif_rx_schedule(netdev);
@@ -2007,7 +2061,7 @@ static int e100_up(struct nic *nic)
         if((err = e100_hw_init(nic)))
                 goto err_clean_cbs;
         e100_set_multicast_list(nic->netdev);
-        e100_start_receiver(nic);
+        e100_start_receiver(nic, NULL);
         mod_timer(&nic->watchdog, jiffies);
         if((err = request_irq(nic->pdev->irq, e100_intr, IRQF_SHARED,
                 nic->netdev->name, nic->netdev)))
@@ -2088,7 +2142,7 @@ static int e100_loopback_test(struct nic *nic, enum loopback loopback_mode)
                 mdio_write(nic->netdev, nic->mii.phy_id, MII_BMCR,
                         BMCR_LOOPBACK);
 
-        e100_start_receiver(nic);
+        e100_start_receiver(nic, NULL);
 
         if(!(skb = netdev_alloc_skb(nic->netdev, ETH_DATA_LEN))) {
                 err = -ENOMEM;