diff options
| author | Matt Mackall <mpm@selenic.com> | 2005-08-12 02:27:43 (GMT) |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2005-08-12 02:27:43 (GMT) |
| commit | 53fb95d3c14290fd6ee808b221e35493f096246f (patch) | |
| tree | 146c31c79bbc66d8fde3afa5ae37a04b63041eba | |
| parent | 2652076507b662fc88ba16c27b59c7bdd9ccd956 (diff) | |
| download | linux-53fb95d3c14290fd6ee808b221e35493f096246f.tar.xz | |
[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>
| -rw-r--r-- | include/linux/netpoll.h | 19 | ||||
| -rw-r--r-- | net/core/dev.c | 9 | ||||
| -rw-r--r-- | net/core/netpoll.c | 3 |
3 files changed, 21 insertions, 10 deletions
diff --git a/include/linux/netpoll.h b/include/linux/netpoll.h index be68d94..5ade54a 100644 --- a/include/linux/netpoll.h +++ b/include/linux/netpoll.h @@ -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 diff --git a/net/core/dev.c b/net/core/dev.c index 52a3bf7a..faf59b0 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1696,7 +1696,8 @@ 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(); while (!list_empty(&queue->poll_list)) { @@ -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(); } diff --git a/net/core/netpoll.c b/net/core/netpoll.c index c02a08d..996787b 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -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: |