diff options
Diffstat (limited to 'net/core/gro_cells.c')
| -rw-r--r-- | net/core/gro_cells.c | 36 |
1 files changed, 31 insertions, 5 deletions
diff --git a/net/core/gro_cells.c b/net/core/gro_cells.c index 6eb2e5ec2c50..8462f926ab45 100644 --- a/net/core/gro_cells.c +++ b/net/core/gro_cells.c @@ -89,8 +89,23 @@ int gro_cells_init(struct gro_cells *gcells, struct net_device *dev) } EXPORT_SYMBOL(gro_cells_init); +struct percpu_free_defer { + struct rcu_head rcu; + void __percpu *ptr; +}; + +static void percpu_free_defer_callback(struct rcu_head *head) +{ + struct percpu_free_defer *defer; + + defer = container_of(head, struct percpu_free_defer, rcu); + free_percpu(defer->ptr); + kfree(defer); +} + void gro_cells_destroy(struct gro_cells *gcells) { + struct percpu_free_defer *defer; int i; if (!gcells->cells) @@ -102,12 +117,23 @@ void gro_cells_destroy(struct gro_cells *gcells) __netif_napi_del(&cell->napi); __skb_queue_purge(&cell->napi_skbs); } - /* This barrier is needed because netpoll could access dev->napi_list - * under rcu protection. + /* We need to observe an rcu grace period before freeing ->cells, + * because netpoll could access dev->napi_list under rcu protection. + * Try hard using call_rcu() instead of synchronize_rcu(), + * because we might be called from cleanup_net(), and we + * definitely do not want to block this critical task. */ - synchronize_net(); - - free_percpu(gcells->cells); + defer = kmalloc(sizeof(*defer), GFP_KERNEL | __GFP_NOWARN); + if (likely(defer)) { + defer->ptr = gcells->cells; + call_rcu(&defer->rcu, percpu_free_defer_callback); + } else { + /* We do not hold RTNL at this point, synchronize_net() + * would not be able to expedite this sync. + */ + synchronize_rcu_expedited(); + free_percpu(gcells->cells); + } gcells->cells = NULL; } EXPORT_SYMBOL(gro_cells_destroy); |