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Commit 0db1d6fc authored by Matt Mackall's avatar Matt Mackall Committed by David S. Miller
Browse files

[NETPOLL]: add retry timeout 



Add limited retry logic to netpoll_send_skb

Each time we attempt to send, decrement our per-device retry counter.
On every successful send, we reset the counter. 

We delay 50us between attempts with up to 20000 retries for a total of
1 second. After we've exhausted our retries, subsequent failed
attempts will try only once until reset by success.

Signed-off-by: default avatarMatt Mackall <mpm@selenic.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f0d3459d

include/linux/netpoll.h

+1 −0
Original line number Diff line number Diff line
@@ -26,6 +26,7 @@ struct netpoll { 
struct netpoll_info {

	spinlock_t poll_lock;

	int poll_owner;

	int tries;

	int rx_flags;

	spinlock_t rx_lock;

	struct netpoll *rx_np; /* netpoll that registered an rx_hook */

net/core/netpoll.c

+10 −3
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ 
#define MAX_UDP_CHUNK 1460

#define MAX_SKBS 32

#define MAX_QUEUE_DEPTH (MAX_SKBS / 2)

#define MAX_RETRIES 20000



static DEFINE_SPINLOCK(skb_list_lock);

static int nr_skbs;
@@ -265,7 +266,8 @@ static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb) 
		return;

	}



	while (1) {

	do {

		npinfo->tries--;

		spin_lock(&np->dev->xmit_lock);

		np->dev->xmit_lock_owner = smp_processor_id();
@@ -277,6 +279,7 @@ static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb) 
			np->dev->xmit_lock_owner = -1;

			spin_unlock(&np->dev->xmit_lock);

			netpoll_poll(np);

			udelay(50);

			continue;

		}
@@ -285,12 +288,15 @@ static void netpoll_send_skb(struct netpoll *np, struct sk_buff *skb) 
		spin_unlock(&np->dev->xmit_lock);



		/* success */

		if(!status)

		if(!status) {

			npinfo->tries = MAX_RETRIES; /* reset */

			return;

		}



		/* transmit busy */

		netpoll_poll(np);

	}

		udelay(50);

	} while (npinfo->tries > 0);

}



void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
@@ -642,6 +648,7 @@ int netpoll_setup(struct netpoll *np) 
		npinfo->rx_np = NULL;

		npinfo->poll_lock = SPIN_LOCK_UNLOCKED;

		npinfo->poll_owner = -1;

		npinfo->tries = MAX_RETRIES;

		npinfo->rx_lock = SPIN_LOCK_UNLOCKED;

	} else

		npinfo = ndev->npinfo;