r8152: reduce the frequency of spin_lock

Replace getting one item from a list with getting the whole list one time.

Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
index 3847c3507624d494dc9eba0a07360421b1437c9b..2a778faa96307888fd53e9a8b76b845dce8853cb 100644 (file)
--- a/drivers/net/usb/r8152.c
+++ b/drivers/net/usb/r8152.c
@@ -1299,9 +1299,16 @@ r8152_tx_csum(struct r8152 *tp, struct tx_desc *desc, struct sk_buff *skb)
 
 static int r8152_tx_agg_fill(struct r8152 *tp, struct tx_agg *agg)
 {
+       struct sk_buff_head skb_head, *tx_queue = &tp->tx_queue;
+       unsigned long flags;
        int remain;
        u8 *tx_data;
 
+       __skb_queue_head_init(&skb_head);
+       spin_lock_irqsave(&tx_queue->lock, flags);
+       skb_queue_splice_init(tx_queue, &skb_head);
+       spin_unlock_irqrestore(&tx_queue->lock, flags);
+
        tx_data = agg->head;
        agg->skb_num = agg->skb_len = 0;
        remain = rx_buf_sz;
@@ -1311,14 +1318,14 @@ static int r8152_tx_agg_fill(struct r8152 *tp, struct tx_agg *agg)
                struct sk_buff *skb;
                unsigned int len;
 
-               skb = skb_dequeue(&tp->tx_queue);
+               skb = __skb_dequeue(&skb_head);
                if (!skb)
                        break;
 
                remain -= sizeof(*tx_desc);
                len = skb->len;
                if (remain < len) {
-                       skb_queue_head(&tp->tx_queue, skb);
+                       __skb_queue_head(&skb_head, skb);
                        break;
                }
 
@@ -1336,6 +1343,12 @@ static int r8152_tx_agg_fill(struct r8152 *tp, struct tx_agg *agg)
                remain = rx_buf_sz - (int)(tx_agg_align(tx_data) - agg->head);
        }
 
+       if (!skb_queue_empty(&skb_head)) {
+               spin_lock_irqsave(&tx_queue->lock, flags);
+               skb_queue_splice(&skb_head, tx_queue);
+               spin_unlock_irqrestore(&tx_queue->lock, flags);
+       }
+
        netif_tx_lock(tp->netdev);
 
        if (netif_queue_stopped(tp->netdev) &&
@@ -1354,10 +1367,17 @@ static int r8152_tx_agg_fill(struct r8152 *tp, struct tx_agg *agg)
 static void rx_bottom(struct r8152 *tp)
 {
        unsigned long flags;
-       struct list_head *cursor, *next;
+       struct list_head *cursor, *next, rx_queue;
 
+       if (list_empty(&tp->rx_done))
+               return;
+
+       INIT_LIST_HEAD(&rx_queue);
        spin_lock_irqsave(&tp->rx_lock, flags);
-       list_for_each_safe(cursor, next, &tp->rx_done) {
+       list_splice_init(&tp->rx_done, &rx_queue);
+       spin_unlock_irqrestore(&tp->rx_lock, flags);
+
+       list_for_each_safe(cursor, next, &rx_queue) {
                struct rx_desc *rx_desc;
                struct rx_agg *agg;
                int len_used = 0;
@@ -1366,7 +1386,6 @@ static void rx_bottom(struct r8152 *tp)
                int ret;
 
                list_del_init(cursor);
-               spin_unlock_irqrestore(&tp->rx_lock, flags);
 
                agg = list_entry(cursor, struct rx_agg, list);
                urb = agg->urb;
@@ -1416,13 +1435,13 @@ static void rx_bottom(struct r8152 *tp)
 
 submit:
                ret = r8152_submit_rx(tp, agg, GFP_ATOMIC);
-               spin_lock_irqsave(&tp->rx_lock, flags);
                if (ret && ret != -ENODEV) {
-                       list_add_tail(&agg->list, next);
+                       spin_lock_irqsave(&tp->rx_lock, flags);
+                       list_add_tail(&agg->list, &tp->rx_done);
+                       spin_unlock_irqrestore(&tp->rx_lock, flags);
                        tasklet_schedule(&tp->tl);
                }
        }
-       spin_unlock_irqrestore(&tp->rx_lock, flags);
 }
 
 static void tx_bottom(struct r8152 *tp)
@@ -1496,9 +1515,19 @@ int r8152_submit_rx(struct r8152 *tp, struct rx_agg *agg, gfp_t mem_flags)
 static void rtl_drop_queued_tx(struct r8152 *tp)
 {
        struct net_device_stats *stats = &tp->netdev->stats;
+       struct sk_buff_head skb_head, *tx_queue = &tp->tx_queue;
+       unsigned long flags;
        struct sk_buff *skb;
 
-       while ((skb = skb_dequeue(&tp->tx_queue))) {
+       if (skb_queue_empty(tx_queue))
+               return;
+
+       __skb_queue_head_init(&skb_head);
+       spin_lock_irqsave(&tx_queue->lock, flags);
+       skb_queue_splice_init(tx_queue, &skb_head);
+       spin_unlock_irqrestore(&tx_queue->lock, flags);
+
+       while ((skb = __skb_dequeue(&skb_head))) {
                dev_kfree_skb(skb);
                stats->tx_dropped++;
        }