Commit f67b4599 authored by Dan Williams's avatar Dan Williams
Browse files

net_dma: convert to dma_find_channel 



Use the general-purpose channel allocation provided by dmaengine.

Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 2ba05622

include/linux/netdevice.h

+0 −3
Original line number Diff line number Diff line
@@ -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);

include/net/netdma.h

+0 −11
Original line number Diff line number Diff line
@@ -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);

net/core/dev.c

+0 −40
Original line number Diff line number Diff line
@@ -4827,44 +4827,6 @@ 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
@@ -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:

net/ipv4/tcp.c

+2 −2
Original line number Diff line number Diff line
@@ -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 @@ int tcp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg, 
		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(

net/ipv4/tcp_input.c

+1 −1
Original line number Diff line number Diff line
@@ -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)) {