On 02/03/2017 11:28 AM, Christoph Hellwig wrote:
> On Fri, Feb 03, 2017 at 09:54:50AM +0100, Hannes Reinecke wrote:
>> From: Johannes Thumshirn <jthumshirn@xxxxxxx>
>>
>> Check for a valid direction before starting the request, otherwise we risk
>> running into an assertion in the scsi midlayer checking for vaild requests.
>
> Good idea, but..
>
>> +static bool sg_is_valid_direction(int dxfer_direction)
>> +{
>> + switch (dxfer_direction) {
>> + case SG_DXFER_NONE:
>> + case SG_DXFER_TO_DEV:
>> + case SG_DXFER_FROM_DEV:
>> + case SG_DXFER_TO_FROM_DEV:
>
> This isn't strictly valid as sg doesn't actually handle real bidi
> commands, but we work around it.
>
> It might be a good idea to move the warning about it from sg_write
> to here and use printk_ratelimited instead of the hand-rolled
> per-thread warning there.
>
>> + case SG_DXFER_UNKNOWN:
>> + return true;
>
> And how valid is this one (Question to Doug I guess): for a 0-sized
> transfer we should be fine, but otherwise it should probably be
> rejected.
>
yes, we should be checking for dxferp and dxfer_len here, too.
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@xxxxxxx +49 911 74053 688
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