Re: Oops in scsi_send_eh_cmnd 2.6.21-rc5-git6,7,10,13

Douglas Gilbert
2007-04-06T16:32:31Z

James Bottomley wrote:
> On Fri, 2007-04-06 at 08:51 -0700, Andrew Burgess wrote:
>> James Bottomley wrote:
>>
>>> It's actually a long standing bug in the 3w-xxxx driver. Apparently it
>>> assumes request sense is always the use_sg == 0 case. This is what it
>>> does on a request sense:
>>> static int tw_scsiop_request_sense(TW_Device_Extension *tw_dev, int request_id)
>>> {
>>> dprintk(KERN_NOTICE "3w-xxxx: tw_scsiop_request_sense()\n");
>>> /* For now we just zero the request buffer */
>>> memset(tw_dev->srb[request_id]->request_buffer, 0, tw_dev->srb[request_id]->request_bufflen);
>>> tw_dev->state[request_id] = TW_S_COMPLETED;
>>> tw_state_request_finish(tw_dev, request_id);
>>> ....
>>> Note that it's clearing the request buffer, which is actually zeroing the scatterlist, hence the problem.
>> OK. Is there a quick workaround or should I just wait for
>> Adam & Company to make a patch?
>
> Try this ... I think it's roughly the correct fix.
>
>> You said your earlier patch would hide it, and then said you
>> had a length wrong in it and I'm not sure what length you
>> mean.
>
> It's the length specifier in the error handler request sense command ...
> I'll fix it up and redo my patch through scsi-misc, since it's not going
> to fix the root cause of the problem.
>
> James
>
> diff --git a/drivers/scsi/3w-xxxx.c b/drivers/scsi/3w-xxxx.c
> index bf5d63e..6b303ba 100644
> --- a/drivers/scsi/3w-xxxx.c
> +++ b/drivers/scsi/3w-xxxx.c
> @@ -1864,10 +1864,17 @@ static int tw_scsiop_read_write(TW_Device_Extension *tw_dev, int request_id)
> /* This function will handle the request sense scsi command */
> static int tw_scsiop_request_sense(TW_Device_Extension *tw_dev, int request_id)
> {
> + char request_buffer[18];
> +
> dprintk(KERN_NOTICE "3w-xxxx: tw_scsiop_request_sense()\n");
>
> - /* For now we just zero the request buffer */
> - memset(tw_dev->srb[request_id]->request_buffer, 0, tw_dev->srb[request_id]->request_bufflen);
> + memset(request_buffer, 0, sizeof(request_buffer));
> + request_buffer[0] = 0x70; /* Immediate fixed format */
> + request_buffer[7] = 11; /* minimum size per SPC: 18 bytes */

James,
That last line should be:
request_buffer[7] = 10; /* minimum size per SPC: 18 bytes */

Doug Gilbert