netdev - Re: [PATCH net-next 2/4] bonding: Do not ignore notifications for miimon-work-queue

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Date:	Thu, 12 Mar 2015 02:34:40 -0700
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Mahesh Bandewar <maheshb@...gle.com>
Cc:	Jay Vosburgh <j.vosburgh@...il.com>,
	Andy Gospodarek <andy@...yhouse.net>,
	Veaceslav Falico <vfalico@...il.com>,
	Nikolay Aleksandrov <nikolay@...hat.com>,
	David Miller <davem@...emloft.net>,
	Maciej Zenczykowski <maze@...gle.com>,
	netdev <netdev@...r.kernel.org>,
	Eric Dumazet <edumazet@...gle.com>
Subject: Re: [PATCH net-next 2/4] bonding: Do not ignore notifications for
 miimon-work-queue

On Wed, 2015-03-11 at 22:54 -0700, Mahesh Bandewar wrote:
> This patch adds code to reschedule the mii-work (aggressively)
> just to handle the notification before resuming the regular
> cycle.
> 
> Signed-off-by: Mahesh Bandewar <maheshb@...gle.com>
> ---
>  drivers/net/bonding/bond_main.c | 24 +++++++++++++++---------
>  1 file changed, 15 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
> index 19eabea2d7d9..54ecb7a22bae 100644
> --- a/drivers/net/bonding/bond_main.c
> +++ b/drivers/net/bonding/bond_main.c
> @@ -2143,10 +2143,13 @@ static void bond_mii_monitor(struct work_struct *work)
>  	if (!bond_has_slaves(bond))
>  		goto re_arm;
>  
> -	rcu_read_lock();
> -
> +	if (bond_get_notif_pending(bond, BOND_MII_NOTIF)) {
> +		should_notify_peers = true;
> +		goto re_arm;
> +	}
>  	should_notify_peers = bond_should_notify_peers(bond);
>  
> +	rcu_read_lock();
>  	if (bond_miimon_inspect(bond)) {
>  		rcu_read_unlock();
>  
> @@ -2164,15 +2167,18 @@ static void bond_mii_monitor(struct work_struct *work)
>  		rcu_read_unlock();
>  
>  re_arm:
> -	if (bond->params.miimon)
> -		queue_delayed_work(bond->wq, &bond->mii_work, delay);
> -
>  	if (should_notify_peers) {
> -		if (!rtnl_trylock())
> -			return;
> -		call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, bond->dev);
> -		rtnl_unlock();
> +		if (!rtnl_trylock()) {
> +			delay = 1;
> +			bond_set_notif_pending(bond, BOND_MII_NOTIF, 1);
> +		} else {
> +			call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, bond->dev);
> +			rtnl_unlock();
> +			bond_set_notif_pending(bond, BOND_MII_NOTIF, 0);

You probably should clear notif bit before releasing rtnl

(same remark for patches 3 & 4)

> +		}
>  	}
> +	if (bond->params.miimon)
> +		queue_delayed_work(bond->wq, &bond->mii_work, delay);
>  }
>  
>  static bool bond_has_this_ip(struct bonding *bond, __be32 ip)


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