[PATCH 06/13] net_dma: convert to dma_find_channel

From: Dan Williams
Date: Fri Nov 14 2008 - 16:37:49 EST


Use the general-purpose channel allocation provided by dmaengine.

Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---

include/linux/netdevice.h | 3 ---
include/net/netdma.h | 11 -----------
net/core/dev.c | 40 ----------------------------------------
net/ipv4/tcp.c | 4 ++--
net/ipv4/tcp_input.c | 2 +-
net/ipv4/tcp_ipv4.c | 2 +-
net/ipv6/tcp_ipv6.c | 2 +-
7 files changed, 5 insertions(+), 59 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 9d77b1d..800866e 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1004,9 +1004,6 @@ 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 cbe2737..8ba8ce2 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 301a449..56e6965 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4591,44 +4591,6 @@ 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
@@ -4657,7 +4619,6 @@ 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:
@@ -4672,7 +4633,6 @@ 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 40ec69f..5da9edb 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1315,7 +1315,7 @@ 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);
@@ -1525,7 +1525,7 @@ 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 d77c0d2..620ca4e 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4682,7 +4682,7 @@ 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 5c8fa7f..b671d49 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1600,7 +1600,7 @@ 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 b6b356b..d41a896 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

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