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-rw-r--r--net/core/gro_cells.c43
1 files changed, 34 insertions, 9 deletions
diff --git a/net/core/gro_cells.c b/net/core/gro_cells.c
index 6eb2e5ec2c50..ed5ec5de47f6 100644
--- a/net/core/gro_cells.c
+++ b/net/core/gro_cells.c
@@ -26,9 +26,9 @@ int gro_cells_receive(struct gro_cells *gcells, struct sk_buff *skb)
cell = this_cpu_ptr(gcells->cells);
- if (skb_queue_len(&cell->napi_skbs) > netdev_max_backlog) {
+ if (skb_queue_len(&cell->napi_skbs) > READ_ONCE(netdev_max_backlog)) {
drop:
- atomic_long_inc(&dev->rx_dropped);
+ dev_core_stats_rx_dropped_inc(dev);
kfree_skb(skb);
res = NET_RX_DROP;
goto unlock;
@@ -81,16 +81,30 @@ int gro_cells_init(struct gro_cells *gcells, struct net_device *dev)
set_bit(NAPI_STATE_NO_BUSY_POLL, &cell->napi.state);
- netif_napi_add(dev, &cell->napi, gro_cell_poll,
- NAPI_POLL_WEIGHT);
+ netif_napi_add(dev, &cell->napi, gro_cell_poll);
napi_enable(&cell->napi);
}
return 0;
}
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 +116,23 @@ 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);