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

James Bottomley
2007-04-06T16:14:56Z

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 */
+ /* leave all other fields zero, giving effectively NO_SENSE return */
+ tw_transfer_internal(tw_dev, request_id, request_buffer,
+ sizeof(request_buffer));
+
tw_dev->state[request_id] = TW_S_COMPLETED;
tw_state_request_finish(tw_dev, request_id);