[NETPOLL]: fix initialization/NAPI race
This fixes a race during initialization with the NAPI softirq processing by using an RCU approach. This race was discovered when refill_skbs() was added to the setup code. Signed-off-by: Matt Mackall <mpm@selenic.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
2652076507
commit
53fb95d3c1
|
@ -9,6 +9,7 @@
|
|||
|
||||
#include <linux/netdevice.h>
|
||||
#include <linux/interrupt.h>
|
||||
#include <linux/rcupdate.h>
|
||||
#include <linux/list.h>
|
||||
|
||||
struct netpoll;
|
||||
|
@ -61,25 +62,31 @@ static inline int netpoll_rx(struct sk_buff *skb)
|
|||
return ret;
|
||||
}
|
||||
|
||||
static inline void netpoll_poll_lock(struct net_device *dev)
|
||||
static inline void *netpoll_poll_lock(struct net_device *dev)
|
||||
{
|
||||
rcu_read_lock(); /* deal with race on ->npinfo */
|
||||
if (dev->npinfo) {
|
||||
spin_lock(&dev->npinfo->poll_lock);
|
||||
dev->npinfo->poll_owner = smp_processor_id();
|
||||
return dev->npinfo;
|
||||
}
|
||||
return NULL;
|
||||
}
|
||||
|
||||
static inline void netpoll_poll_unlock(struct net_device *dev)
|
||||
static inline void netpoll_poll_unlock(void *have)
|
||||
{
|
||||
if (dev->npinfo) {
|
||||
dev->npinfo->poll_owner = -1;
|
||||
spin_unlock(&dev->npinfo->poll_lock);
|
||||
struct netpoll_info *npi = have;
|
||||
|
||||
if (npi) {
|
||||
npi->poll_owner = -1;
|
||||
spin_unlock(&npi->poll_lock);
|
||||
}
|
||||
rcu_read_unlock();
|
||||
}
|
||||
|
||||
#else
|
||||
#define netpoll_rx(a) 0
|
||||
#define netpoll_poll_lock(a)
|
||||
#define netpoll_poll_lock(a) 0
|
||||
#define netpoll_poll_unlock(a)
|
||||
#endif
|
||||
|
||||
|
|
|
@ -1696,6 +1696,7 @@ static void net_rx_action(struct softirq_action *h)
|
|||
struct softnet_data *queue = &__get_cpu_var(softnet_data);
|
||||
unsigned long start_time = jiffies;
|
||||
int budget = netdev_budget;
|
||||
void *have;
|
||||
|
||||
local_irq_disable();
|
||||
|
||||
|
@ -1709,10 +1710,10 @@ static void net_rx_action(struct softirq_action *h)
|
|||
|
||||
dev = list_entry(queue->poll_list.next,
|
||||
struct net_device, poll_list);
|
||||
netpoll_poll_lock(dev);
|
||||
have = netpoll_poll_lock(dev);
|
||||
|
||||
if (dev->quota <= 0 || dev->poll(dev, &budget)) {
|
||||
netpoll_poll_unlock(dev);
|
||||
netpoll_poll_unlock(have);
|
||||
local_irq_disable();
|
||||
list_del(&dev->poll_list);
|
||||
list_add_tail(&dev->poll_list, &queue->poll_list);
|
||||
|
@ -1721,7 +1722,7 @@ static void net_rx_action(struct softirq_action *h)
|
|||
else
|
||||
dev->quota = dev->weight;
|
||||
} else {
|
||||
netpoll_poll_unlock(dev);
|
||||
netpoll_poll_unlock(have);
|
||||
dev_put(dev);
|
||||
local_irq_disable();
|
||||
}
|
||||
|
|
|
@ -732,6 +732,9 @@ int netpoll_setup(struct netpoll *np)
|
|||
/* last thing to do is link it to the net device structure */
|
||||
ndev->npinfo = npinfo;
|
||||
|
||||
/* avoid racing with NAPI reading npinfo */
|
||||
synchronize_rcu();
|
||||
|
||||
return 0;
|
||||
|
||||
release:
|
||||
|
|
Loading…
Reference in a new issue