[NETPOLL]: Fixups for 'fix soft lockup when removing module'

>From my recent patch:

> >    #1
> >    Until kernel ver. 2.6.21 (including) cancel_rearming_delayed_work()
> >    required a work function should always (unconditionally) rearm with
> >    delay > 0 - otherwise it would endlessly loop. This patch replaces
> >    this function with cancel_delayed_work(). Later kernel versions don't
> >    require this, so here it's only for uniformity.

But Oleg Nesterov <oleg@tv-sign.ru> found:

> But 2.6.22 doesn't need this change, why it was merged?
> 
> In fact, I suspect this change adds a race,
...

His description was right (thanks), so this patch reverts #1.

Signed-off-by: Jarek Poplawski <jarkao2@o2.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 4 deletions

diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index cf40ff91ac01..a0efdd7a6b37 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -72,8 +72,7 @@ static void queue_process(struct work_struct *work)
                         netif_tx_unlock(dev);
                         local_irq_restore(flags);
 
-                        if (atomic_read(&npinfo->refcnt))
-                                schedule_delayed_work(&npinfo->tx_work, HZ/10);
+                        schedule_delayed_work(&npinfo->tx_work, HZ/10);
                         return;
                 }
                 netif_tx_unlock(dev);
@@ -786,8 +785,7 @@ void netpoll_cleanup(struct netpoll *np)
                         if (atomic_dec_and_test(&npinfo->refcnt)) {
                                 skb_queue_purge(&npinfo->arp_tx);
                                 skb_queue_purge(&npinfo->txq);
-                                cancel_delayed_work(&npinfo->tx_work);
-                                flush_scheduled_work();
+                                cancel_rearming_delayed_work(&npinfo->tx_work);
 
                                 /* clean after last, unfinished work */
                                 if (!skb_queue_empty(&npinfo->txq)) {