[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: Matt Mackall <mpm@selenic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h
index bcd0ac3..be68d94 100644
--- a/include/linux/netpoll.h
+++ b/include/linux/netpoll.h
@@ -26,6 +26,7 @@
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 */
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 59ed186..d09affdb 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -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 @@
return;
}
- while (1) {
+ do {
+ npinfo->tries--;
spin_lock(&np->dev->xmit_lock);
np->dev->xmit_lock_owner = smp_processor_id();
@@ -277,6 +279,7 @@
np->dev->xmit_lock_owner = -1;
spin_unlock(&np->dev->xmit_lock);
netpoll_poll(np);
+ udelay(50);
continue;
}
@@ -285,12 +288,15 @@
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 @@
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;