linux-kernel - Re: [PATCH 1/3] Drivers: hv: vmbus: do cleanup on all vmbus

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Date:	Tue, 21 Apr 2015 13:35:08 +0200
From:	Vitaly Kuznetsov <vkuznets@...hat.com>
To:	Dexuan Cui <decui@...rosoft.com>
Cc:	KY Srinivasan <kys@...rosoft.com>,
	Haiyang Zhang <haiyangz@...rosoft.com>,
	"devel\@linuxdriverproject.org" <devel@...uxdriverproject.org>,
	"linux-kernel\@vger.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/3] Drivers: hv: vmbus: do cleanup on all vmbus_open() failure paths

Dexuan Cui <decui@...rosoft.com> writes:

>> -----Original Message-----
>> From: Vitaly Kuznetsov [mailto:vkuznets@...hat.com]
>> Sent: Tuesday, April 21, 2015 16:18
>> To: KY Srinivasan
>> Cc: Haiyang Zhang; devel@...uxdriverproject.org; linux-
>> kernel@...r.kernel.org; Dexuan Cui
>> Subject: [PATCH 1/3] Drivers: hv: vmbus: do cleanup on all vmbus_open()
>> failure paths
>> 
>> In case there was an error reported in the response to the
>> CHANNELMSG_OPENCHANNEL
>> call we need to do the cleanup as a vmbus_open() user won't be doing it
>> after
>> receiving an error. The cleanup should be done on all failure paths.
>> 
>> Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.com>
>> ---
>>  drivers/hv/channel.c | 7 ++++---
>>  1 file changed, 4 insertions(+), 3 deletions(-)
>> 
>> diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
>> index 54da66d..836386f 100644
>> --- a/drivers/hv/channel.c
>> +++ b/drivers/hv/channel.c
>> @@ -186,11 +186,12 @@ int vmbus_open(struct vmbus_channel
>> *newchannel, u32 send_ringbuffer_size,
>>  	list_del(&open_info->msglistentry);
>>  	spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock,
>> flags);
>> 
>> -	if (err == 0)
>> -		newchannel->state = CHANNEL_OPENED_STATE;
>> +	if (err != 0)
>> +		goto error_gpadl;
>> 
>> +	newchannel->state = CHANNEL_OPENED_STATE;
>>  	kfree(open_info);
>> -	return err;
>> +	return 0;
>> 
>>  error1:
>>  	spin_lock_irqsave(&vmbus_connection.channelmsg_lock, flags);
>> --
>
> Thanks for the patch, Vitaly!
>
> The patch looks good to me except for 1 small issue:
> I suppose open_info->response.open_result.status is different from
> Linux-style -EXXX error codes.
>
> Maybe here we can return -EAGAIN if err != 0 ?

I think I inspected all vmbus_open() callers and they all just check ret
!= 0 but I agree we'd better return some -EXXXX code here. I'm not
exactly sure if open_result.status != 0 usually means a permanent or a
temporary failure but if it's temporary -EAGAIN here seems reasonable.

I'll send v2, thanks for the review!

>
> -- Dexuan

-- 
  Vitaly
--
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