[NETFILTER]: nfnetlink_queue: avoid unnecessary atomic operation
Patrick McHardy [Wed, 5 Dec 2007 09:28:10 +0000 (01:28 -0800)]
The sequence counter doesn't need to be an atomic_t, just move the increment
inside the locked section.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/netfilter/nfnetlink_queue.c

index d9ce394..bd18de7 100644 (file)
@@ -56,7 +56,7 @@ struct nfqnl_instance {
        unsigned int queue_dropped;
        unsigned int queue_user_dropped;
 
-       atomic_t id_sequence;                   /* 'sequence' of pkt ids */
+       unsigned int id_sequence;               /* 'sequence' of pkt ids */
 
        u_int16_t queue_num;                    /* number of this queue */
        u_int8_t copy_mode;
@@ -139,7 +139,6 @@ instance_create(u_int16_t queue_num, int pid)
        inst->queue_maxlen = NFQNL_QMAX_DEFAULT;
        inst->copy_range = 0xfffff;
        inst->copy_mode = NFQNL_COPY_NONE;
-       atomic_set(&inst->id_sequence, 0);
        /* needs to be two, since we _put() after creation */
        atomic_set(&inst->use, 2);
        spin_lock_init(&inst->lock);
@@ -340,6 +339,8 @@ nfqnl_build_packet_message(struct nfqnl_instance *queue,
                return NULL;
        }
 
+       entry->id = queue->id_sequence++;
+
        spin_unlock_bh(&queue->lock);
 
        skb = alloc_skb(size, GFP_ATOMIC);
@@ -496,8 +497,6 @@ nfqnl_enqueue_packet(struct nf_queue_entry *entry, unsigned int queuenum)
                goto err_out_put;
        }
 
-       entry->id = atomic_inc_return(&queue->id_sequence);
-
        nskb = nfqnl_build_packet_message(queue, entry, &status);
        if (nskb == NULL)
                goto err_out_put;
@@ -948,7 +947,7 @@ static int seq_show(struct seq_file *s, void *v)
                          inst->peer_pid, inst->queue_total,
                          inst->copy_mode, inst->copy_range,
                          inst->queue_dropped, inst->queue_user_dropped,
-                         atomic_read(&inst->id_sequence),
+                         inst->id_sequence,
                          atomic_read(&inst->use));
 }