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Message-ID: <d2696256-639b-4b20-3612-6dcfe68313a1@mev.co.uk>
Date:   Tue, 7 Jun 2022 17:50:11 +0100
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Subject: Re: [PATCH] comedi: vmk80xx: fix expression for tx buffer size
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To:     Johan Hovold <johan@kernel.org>
Cc:     linux-kernel@vger.kernel.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        H Hartley Sweeten <hsweeten@visionengravers.com>,
        stable@vger.kernel.org
References: <20220606105237.13937-1-abbotti@mev.co.uk>
 <Yp95+QKSqeH5AG0a@hovoldconsulting.com>
From:   Ian Abbott <abbotti@mev.co.uk>
Organization: MEV Ltd.
In-Reply-To: <Yp95+QKSqeH5AG0a@hovoldconsulting.com>
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On 07/06/2022 17:16, Johan Hovold wrote:
> On Mon, Jun 06, 2022 at 11:52:37AM +0100, Ian Abbott wrote:
>> The expression for setting the size of the allocated bulk TX buffer
>> (`devpriv->usb_tx_buf`) is calling `usb_endpoint_maxp(devpriv->ep_rx)`,
>> which is using the wrong endpoint (should be `devpriv->ep_tx`).  Fix it.
> 
> Bah. Good catch.
> 
>> Fixes: a23461c47482 ("comedi: vmk80xx: fix transfer-buffer overflow")
>> Cc: Johan Hovold <johan@kernel.org>
>> Cc: stable@vger.kernel.org # 5.10, 5.15+
> 
> I believe this one is needed in all stable trees (e.g. 4.9+).

True.  I didn't think the patch it fixes had been applied yet, but I 
didn't look hard enough.  I'll send a v2 with amended Cc line.

> 
>> Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
>> ---
>>   drivers/comedi/drivers/vmk80xx.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/comedi/drivers/vmk80xx.c b/drivers/comedi/drivers/vmk80xx.c
>> index 46023adc5395..4536ed43f65b 100644
>> --- a/drivers/comedi/drivers/vmk80xx.c
>> +++ b/drivers/comedi/drivers/vmk80xx.c
>> @@ -684,7 +684,7 @@ static int vmk80xx_alloc_usb_buffers(struct comedi_device *dev)
>>   	if (!devpriv->usb_rx_buf)
>>   		return -ENOMEM;
>>   
>> -	size = max(usb_endpoint_maxp(devpriv->ep_rx), MIN_BUF_SIZE);
>> +	size = max(usb_endpoint_maxp(devpriv->ep_tx), MIN_BUF_SIZE);
>>   	devpriv->usb_tx_buf = kzalloc(size, GFP_KERNEL);
>>   	if (!devpriv->usb_tx_buf)
>>   		return -ENOMEM;
> 
> Looks good otherwise:
> 
> Reviewed-by: Johan Hovold <johan@kernel.org>

Thanks for the review!

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