net_dma: convert to dma_find_channel
Dan Williams [Tue, 6 Jan 2009 18:38:15 +0000 (11:38 -0700)]
Use the general-purpose channel allocation provided by dmaengine.

Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

include/linux/netdevice.h
include/net/netdma.h
net/core/dev.c
net/ipv4/tcp.c
net/ipv4/tcp_input.c
net/ipv4/tcp_ipv4.c
net/ipv6/tcp_ipv6.c

index 41e1224..bac2c45 100644 (file)
@@ -1113,9 +1113,6 @@ struct softnet_data
        struct sk_buff          *completion_queue;
 
        struct napi_struct      backlog;
-#ifdef CONFIG_NET_DMA
-       struct dma_chan         *net_dma;
-#endif
 };
 
 DECLARE_PER_CPU(struct softnet_data,softnet_data);
index cbe2737..8ba8ce2 100644 (file)
 #include <linux/dmaengine.h>
 #include <linux/skbuff.h>
 
-static inline struct dma_chan *get_softnet_dma(void)
-{
-       struct dma_chan *chan;
-
-       rcu_read_lock();
-       chan = rcu_dereference(__get_cpu_var(softnet_data).net_dma);
-       rcu_read_unlock();
-
-       return chan;
-}
-
 int dma_skb_copy_datagram_iovec(struct dma_chan* chan,
                struct sk_buff *skb, int offset, struct iovec *to,
                size_t len, struct dma_pinned_list *pinned_list);
index e40b0d5..bbb07db 100644 (file)
@@ -4828,44 +4828,6 @@ static int dev_cpu_callback(struct notifier_block *nfb,
 
 #ifdef CONFIG_NET_DMA
 /**
- * net_dma_rebalance - try to maintain one DMA channel per CPU
- * @net_dma: DMA client and associated data (lock, channels, channel_mask)
- *
- * This is called when the number of channels allocated to the net_dma client
- * changes.  The net_dma client tries to have one DMA channel per CPU.
- */
-
-static void net_dma_rebalance(struct net_dma *net_dma)
-{
-       unsigned int cpu, i, n, chan_idx;
-       struct dma_chan *chan;
-
-       if (cpus_empty(net_dma->channel_mask)) {
-               for_each_online_cpu(cpu)
-                       rcu_assign_pointer(per_cpu(softnet_data, cpu).net_dma, NULL);
-               return;
-       }
-
-       i = 0;
-       cpu = first_cpu(cpu_online_map);
-
-       for_each_cpu_mask_nr(chan_idx, net_dma->channel_mask) {
-               chan = net_dma->channels[chan_idx];
-
-               n = ((num_online_cpus() / cpus_weight(net_dma->channel_mask))
-                  + (i < (num_online_cpus() %
-                       cpus_weight(net_dma->channel_mask)) ? 1 : 0));
-
-               while(n) {
-                       per_cpu(softnet_data, cpu).net_dma = chan;
-                       cpu = next_cpu(cpu, cpu_online_map);
-                       n--;
-               }
-               i++;
-       }
-}
-
-/**
  * netdev_dma_event - event callback for the net_dma_client
  * @client: should always be net_dma_client
  * @chan: DMA channel for the event
@@ -4894,7 +4856,6 @@ netdev_dma_event(struct dma_client *client, struct dma_chan *chan,
                        ack = DMA_ACK;
                        net_dma->channels[pos] = chan;
                        cpu_set(pos, net_dma->channel_mask);
-                       net_dma_rebalance(net_dma);
                }
                break;
        case DMA_RESOURCE_REMOVED:
@@ -4909,7 +4870,6 @@ netdev_dma_event(struct dma_client *client, struct dma_chan *chan,
                        ack = DMA_ACK;
                        cpu_clear(pos, net_dma->channel_mask);
                        net_dma->channels[i] = NULL;
-                       net_dma_rebalance(net_dma);
                }
                break;
        default:
index 75e0e0a..9b275ab 100644 (file)
@@ -1317,7 +1317,7 @@ int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
                if ((available < target) &&
                    (len > sysctl_tcp_dma_copybreak) && !(flags & MSG_PEEK) &&
                    !sysctl_tcp_low_latency &&
-                   __get_cpu_var(softnet_data).net_dma) {
+                   dma_find_channel(DMA_MEMCPY)) {
                        preempt_enable_no_resched();
                        tp->ucopy.pinned_list =
                                        dma_pin_iovec_pages(msg->msg_iov, len);
@@ -1527,7 +1527,7 @@ do_prequeue:
                if (!(flags & MSG_TRUNC)) {
 #ifdef CONFIG_NET_DMA
                        if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
-                               tp->ucopy.dma_chan = get_softnet_dma();
+                               tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
 
                        if (tp->ucopy.dma_chan) {
                                tp->ucopy.dma_cookie = dma_skb_copy_datagram_iovec(
index 99b7ecb..a6961d7 100644 (file)
@@ -5005,7 +5005,7 @@ static int tcp_dma_try_early_copy(struct sock *sk, struct sk_buff *skb,
                return 0;
 
        if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
-               tp->ucopy.dma_chan = get_softnet_dma();
+               tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
 
        if (tp->ucopy.dma_chan && skb_csum_unnecessary(skb)) {
 
index 9d839fa..19d7b42 100644 (file)
@@ -1594,7 +1594,7 @@ process:
 #ifdef CONFIG_NET_DMA
                struct tcp_sock *tp = tcp_sk(sk);
                if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
-                       tp->ucopy.dma_chan = get_softnet_dma();
+                       tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
                if (tp->ucopy.dma_chan)
                        ret = tcp_v4_do_rcv(sk, skb);
                else
index e8b8337..71cd709 100644 (file)
@@ -1640,7 +1640,7 @@ process:
 #ifdef CONFIG_NET_DMA
                struct tcp_sock *tp = tcp_sk(sk);
                if (!tp->ucopy.dma_chan && tp->ucopy.pinned_list)
-                       tp->ucopy.dma_chan = get_softnet_dma();
+                       tp->ucopy.dma_chan = dma_find_channel(DMA_MEMCPY);
                if (tp->ucopy.dma_chan)
                        ret = tcp_v6_do_rcv(sk, skb);
                else