On Thu, 2016-08-25 at 16:58 +0200, Paolo Abeni wrote:
> On Thu, 2016-08-25 at 07:47 -0700, Eric Dumazet wrote:
> > On Thu, 2016-08-25 at 07:32 -0700, Eric Dumazet wrote:
> >
> > > In a future patch, we could change this so that we kick
> > > flush_all_backlogs() once for all devices, instead of one device at a
> > > time.
> > >
> > > We would not pass @dev anymore as a parameter and simply look at
> > > skb->dev->reg_state to decide to remove packets from queues in
> > > flush_backlog()
> >
> > This would be something like :
>
> This is actually a nice cleanup. I hope to test it later.
>
> > diff --git a/net/core/dev.c b/net/core/dev.c
> > index 7feae74ca928..793ace2c600f 100644
> > --- a/net/core/dev.c
> > +++ b/net/core/dev.c
> > @@ -4293,7 +4293,6 @@ int netif_receive_skb(struct sk_buff *skb)
> > EXPORT_SYMBOL(netif_receive_skb);
> >
> > struct flush_work {
> > - struct net_device *dev;
> > struct work_struct work;
> > };
>
> With 'dev' removal, I think we can use directly 'work_struct' and avoid
> 'container_of' usage in flush_backlog().
Sure. Here is the patch I will propose :
diff --git a/net/core/dev.c b/net/core/dev.c
index 7feae74ca928..996107f041a3 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4292,18 +4292,11 @@ int netif_receive_skb(struct sk_buff *skb)
}
EXPORT_SYMBOL(netif_receive_skb);
-struct flush_work {
- struct net_device *dev;
- struct work_struct work;
-};
-
-DEFINE_PER_CPU(struct flush_work, flush_works);
+DEFINE_PER_CPU(struct work_struct, flush_works);
/* Network device is going away, flush any packets still pending */
static void flush_backlog(struct work_struct *work)
{
- struct flush_work *flush = container_of(work, typeof(*flush), work);
- struct net_device *dev = flush->dev;
struct sk_buff *skb, *tmp;
struct softnet_data *sd;
@@ -4313,7 +4306,7 @@ static void flush_backlog(struct work_struct *work)
local_irq_disable();
rps_lock(sd);
skb_queue_walk_safe(&sd->input_pkt_queue, skb, tmp) {
- if (skb->dev == dev) {
+ if (skb->dev->reg_state == NETREG_UNREGISTERING) {
__skb_unlink(skb, &sd->input_pkt_queue);
kfree_skb(skb);
input_queue_head_incr(sd);
@@ -4323,7 +4316,7 @@ static void flush_backlog(struct work_struct *work)
local_irq_enable();
skb_queue_walk_safe(&sd->process_queue, skb, tmp) {
- if (skb->dev == dev) {
+ if (skb->dev->reg_state == NETREG_UNREGISTERING) {
__skb_unlink(skb, &sd->process_queue);
kfree_skb(skb);
input_queue_head_incr(sd);
@@ -4332,22 +4325,18 @@ static void flush_backlog(struct work_struct *work)
local_bh_enable();
}
-static void flush_all_backlogs(struct net_device *dev)
+static void flush_all_backlogs(void)
{
unsigned int cpu;
get_online_cpus();
- for_each_online_cpu(cpu) {
- struct flush_work *flush = per_cpu_ptr(&flush_works, cpu);
-
- INIT_WORK(&flush->work, flush_backlog);
- flush->dev = dev;
- queue_work_on(cpu, system_highpri_wq, &flush->work);
- }
+ for_each_online_cpu(cpu)
+ queue_work_on(cpu, system_highpri_wq,
+ per_cpu_ptr(&flush_works, cpu));
for_each_online_cpu(cpu)
- flush_work(&per_cpu_ptr(&flush_works, cpu)->work);
+ flush_work(per_cpu_ptr(&flush_works, cpu));
put_online_cpus();
}
@@ -6735,8 +6724,8 @@ static void rollback_registered_many(struct list_head
*head)
unlist_netdevice(dev);
dev->reg_state = NETREG_UNREGISTERING;
- flush_all_backlogs(dev);
}
+ flush_all_backlogs();
synchronize_net();
@@ -8301,8 +8290,11 @@ static int __init net_dev_init(void)
*/
for_each_possible_cpu(i) {
+ struct work_struct *flush = per_cpu_ptr(&flush_works, i);
struct softnet_data *sd = &per_cpu(softnet_data, i);
+ INIT_WORK(flush, flush_backlog);
+
skb_queue_head_init(&sd->input_pkt_queue);
skb_queue_head_init(&sd->process_queue);
INIT_LIST_HEAD(&sd->poll_list);
