Subject: Re: [PATCH] kvaser_usb: fix "dma on the stack" errors

From: Marc Kleine-Budde <[email-masked]>
Date: Fri, 23 Nov 2012 14:48:39 +0100

On 11/23/2012 02:40 PM, Olivier Sobrie wrote:
> On Fri, Nov 23, 2012 at 02:30:28PM +0100, Olivier Sobrie wrote:
>> The dma buffer given to usb_bulk_msg() must be allocated and not on
>> the stack.
>> See Documentation/DMA-API-HOWTO.txt section "What memory is DMA'able?"
>>
>> Signed-off-by: Olivier Sobrie <[email-masked]>
>> ---
>> Here is the incremental patch.
>> Thank you Greg !
>>
>> Olivier
>>
>>  drivers/net/can/usb/kvaser_usb.c |  110 ++++++++++++++++++++++++--------------
>>  1 file changed, 69 insertions(+), 41 deletions(-)
>>
>> diff --git a/drivers/net/can/usb/kvaser_usb.c b/drivers/net/can/usb/kvaser_usb.c
>> index 8807bf8..7ac6e82 100644
>> --- a/drivers/net/can/usb/kvaser_usb.c
>> +++ b/drivers/net/can/usb/kvaser_usb.c
>> @@ -421,14 +421,21 @@ end:
>>  static int kvaser_usb_send_simple_msg(const struct kvaser_usb *dev,
>>  				      u8 msg_id, int channel)
>>  {
>> -	struct kvaser_msg msg = {
>> -		.len = MSG_HEADER_LEN + sizeof(struct kvaser_msg_simple),
>> -		.id = msg_id,
>> -		.u.simple.channel = channel,
>> -		.u.simple.tid = 0xff,
>> -	};
>> -
>> -	return kvaser_usb_send_msg(dev, &msg);
>> +	struct kvaser_msg *msg;
>> +	int rc;
>> +
>> +	msg = kmalloc(sizeof(*msg), GFP_KERNEL);
>> +	if (!msg)
>> +		return -ENOMEM;
>> +
> 
> Doh! I removed by mistake the line "msg->id = msg_id"... grr

Please send a v2 version of this patch with this problem fixed.

MarcMarc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |