linux-kernel - Re: [PATCH 1/1] drivers/hv: cleanup synic msrs if vmbus connect failed

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Date:	Wed, 07 Oct 2015 19:25:34 +0200
From:	Vitaly Kuznetsov <vkuznets@...hat.com>
To:	"Denis V. Lunev" <den@...nvz.org>
Cc:	devel@...uxdriverproject.org, linux-kernel@...r.kernel.org,
	Andrey Smetanin <asmetanin@...tuozzo.com>,
	"K. Y. Srinivasan" <kys@...rosoft.com>,
	Haiyang Zhang <haiyangz@...rosoft.com>
Subject: Re: [PATCH 1/1] drivers/hv: cleanup synic msrs if vmbus connect failed

"Denis V. Lunev" <den@...nvz.org> writes:

> From: Andrey Smetanin <asmetanin@...tuozzo.com>
>
> Before vmbus_connect() synic is setup per vcpu - this means
> hypervisor receives writes at synic msr's and probably allocate
> hypervisor resources per synic setup.
>
> If vmbus_connect() failed for some reason it's neccessary to cleanup
> synic setup by call hv_synic_cleanup() at each vcpu to get a chance
> to free allocated resources by hypervisor per synic.

"to make sure it is safe to free previously allocated resources" (as we
can free them anyway)?

>
> This patch does appropriate cleanup in case of vmbus_connect() failure.
>
> Signed-off-by: Andrey Smetanin <asmetanin@...tuozzo.com>
> Signed-off-by: Denis V. Lunev <den@...nvz.org>
> CC: "K. Y. Srinivasan" <kys@...rosoft.com>
> CC: Haiyang Zhang <haiyangz@...rosoft.com>
> CC: Vitaly Kuznetsov <vkuznets@...hat.com>

Reviewed-by: Vitaly Kuznetsov <vkuznets@...hat.com>

> ---
>  drivers/hv/vmbus_drv.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index f19b6f7..3297731 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -867,7 +867,7 @@ static int vmbus_bus_init(int irq)
>  	on_each_cpu(hv_synic_init, NULL, 1);
>  	ret = vmbus_connect();
>  	if (ret)
> -		goto err_alloc;
> +		goto err_connect;
>
>  	if (vmbus_proto_version > VERSION_WIN7)
>  		cpu_hotplug_disable();
> @@ -885,6 +885,8 @@ static int vmbus_bus_init(int irq)
>
>  	return 0;
>
> +err_connect:
> +	on_each_cpu(hv_synic_cleanup, NULL, 1);
>  err_alloc:
>  	hv_synic_free();
>  	hv_remove_vmbus_irq();

-- 
  Vitaly
--
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