netpoll: Don't drop all received packets.

Change the strategy of netpoll from dropping all packets received
during netpoll_poll_dev to calling napi poll with a budget of 0
(to avoid processing drivers rx queue), and to ignore packets received
with netif_rx (those will safely be placed on the backlog queue).

All of the netpoll supporting drivers have been reviewed to ensure
either thay use netif_rx or that a budget of 0 is supported by their
napi poll routine and that a budget of 0 will not process the drivers
rx queues.

Not dropping packets makes NETPOLL_RX_DROP unnecesary so it is removed.

npinfo->rx_flags is removed  as rx_flags with just the NETPOLL_RX_ENABLED
flag becomes just a redundant mirror of list_empty(&npinfo->rx_np).

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 2 deletions

diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h
index 479d15c97770..154f9776056c 100644
--- a/include/linux/netpoll.h
+++ b/include/linux/netpoll.h
@@ -39,7 +39,6 @@ struct netpoll {
 struct netpoll_info {
         atomic_t refcnt;
 
-        unsigned long rx_flags;
         spinlock_t rx_lock;
         struct semaphore dev_lock;
         struct list_head rx_np; /* netpolls that registered an rx_skb_hook */
@@ -99,7 +98,7 @@ static inline bool netpoll_rx_on(struct sk_buff *skb)
 {
         struct netpoll_info *npinfo = rcu_dereference_bh(skb->dev->npinfo);
 
-        return npinfo && (netpoll_rx_processing(npinfo) || npinfo->rx_flags);
+        return npinfo && netpoll_rx_processing(npinfo);
 }
 
 static inline bool netpoll_rx(struct sk_buff *skb)