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authorEric W. Biederman <ebiederm@xmission.com>2014-03-14 20:48:28 -0700
committerDavid S. Miller <davem@davemloft.net>2014-03-17 15:47:22 -0400
commitb6bacd550c33124ea76291bd84ac42c8d30767eb (patch)
tree19a5fb4f432141125a0bbc16254f8e83b57f3645
parentff6076314339e079806d9d2f3de9c9b768e94db1 (diff)
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>
-rw-r--r--include/linux/netpoll.h3
-rw-r--r--net/core/netpoll.c17
2 files changed, 7 insertions, 13 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)
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index ef83a2530e98..793dc04d2f19 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -51,8 +51,6 @@ static atomic_t trapped;
DEFINE_STATIC_SRCU(netpoll_srcu);
#define USEC_PER_POLL 50
-#define NETPOLL_RX_ENABLED 1
-#define NETPOLL_RX_DROP 2
#define MAX_SKB_SIZE \
(sizeof(struct ethhdr) + \
@@ -193,7 +191,8 @@ static void netpoll_poll_dev(struct net_device *dev)
{
const struct net_device_ops *ops;
struct netpoll_info *ni = rcu_dereference_bh(dev->npinfo);
- int budget = 16;
+ bool rx_processing = netpoll_rx_processing(ni);
+ int budget = rx_processing? 16 : 0;
/* Don't do any rx activity if the dev_lock mutex is held
* the dev_open/close paths use this to block netpoll activity
@@ -207,8 +206,8 @@ static void netpoll_poll_dev(struct net_device *dev)
return;
}
- ni->rx_flags |= NETPOLL_RX_DROP;
- atomic_inc(&trapped);
+ if (rx_processing)
+ atomic_inc(&trapped);
ops = dev->netdev_ops;
if (!ops->ndo_poll_controller) {
@@ -221,8 +220,8 @@ static void netpoll_poll_dev(struct net_device *dev)
poll_napi(dev, budget);
- atomic_dec(&trapped);
- ni->rx_flags &= ~NETPOLL_RX_DROP;
+ if (rx_processing)
+ atomic_dec(&trapped);
up(&ni->dev_lock);
@@ -1050,7 +1049,6 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev, gfp_t gfp)
goto out;
}
- npinfo->rx_flags = 0;
INIT_LIST_HEAD(&npinfo->rx_np);
spin_lock_init(&npinfo->rx_lock);
@@ -1076,7 +1074,6 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev, gfp_t gfp)
if (np->rx_skb_hook) {
spin_lock_irqsave(&npinfo->rx_lock, flags);
- npinfo->rx_flags |= NETPOLL_RX_ENABLED;
list_add_tail(&np->rx, &npinfo->rx_np);
spin_unlock_irqrestore(&npinfo->rx_lock, flags);
}
@@ -1258,8 +1255,6 @@ void __netpoll_cleanup(struct netpoll *np)
if (!list_empty(&npinfo->rx_np)) {
spin_lock_irqsave(&npinfo->rx_lock, flags);
list_del(&np->rx);
- if (list_empty(&npinfo->rx_np))
- npinfo->rx_flags &= ~NETPOLL_RX_ENABLED;
spin_unlock_irqrestore(&npinfo->rx_lock, flags);
}