net_dma: convert to dma_find_channel

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>

7 files changed, 5 insertions, 59 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 41e1224651cf..bac2c458d9b8 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -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);
diff --git a/include/net/netdma.h b/include/net/netdma.h
index cbe2737f4a61..8ba8ce284eeb 100644
--- a/include/net/netdma.h
+++ b/include/net/netdma.h
@@ -24,17 +24,6 @@
 #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);
diff --git a/net/core/dev.c b/net/core/dev.c
index e40b0d57f8ff..bbb07dbe1740 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -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:
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 75e0e0a2d8db..9b275abc8eb9 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -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(
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 99b7ecbe8893..a6961d75c7ea 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -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)) {
 
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 9d839fa9331e..19d7b429a262 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -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
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index e8b8337a8310..71cd70951d7d 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -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