netdev - Re: [PATCH net 2/4] hv_netvsc: reset vf

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Message-ID: <87lh038q26.fsf@vitty.brq.redhat.com>
Date:	Thu, 11 Aug 2016 14:09:53 +0200
From:	Vitaly Kuznetsov <vkuznets@...hat.com>
To:	Yuval Mintz <Yuval.Mintz@...gic.com>
Cc:	netdev <netdev@...r.kernel.org>,
	"devel\@linuxdriverproject.org" <devel@...uxdriverproject.org>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	Haiyang Zhang <haiyangz@...rosoft.com>,
	"K. Y. Srinivasan" <kys@...rosoft.com>
Subject: Re: [PATCH net 2/4] hv_netvsc: reset vf_inject on VF removal

Yuval Mintz <Yuval.Mintz@...gic.com> writes:

>> +static void netvsc_inject_enable(struct net_device_context
>> +*net_device_ctx) {
>> +	net_device_ctx->vf_inject = true;
>> +}
>> +
>> +static void netvsc_inject_disable(struct net_device_context
>> +*net_device_ctx) {
>> +	net_device_ctx->vf_inject = false;
>> +
>> +	/* Wait for currently active users to drain out. */
>> +	while (atomic_read(&net_device_ctx->vf_use_cnt) != 0)
>> +		udelay(50);
>> +}
>
> That was already the behavior before, but are you certain you
> want to unconditionally block without any possible timeout?

Yes, this is OK. After PATCH4 of this series there is only one place
which takes the vf_use_cnt (netvsc_recv_callback()) and it is an
interrupt handler, there are no sleepable operations there.

-- 
  Vitaly