Re: [PATCH] megaraid2 bad queuecommand return

[Jens Axboe <axboe@suse.de>]

On Fri, Nov 19 2004, Mukker, Atul wrote:
> Linux/Documentation/scsi/scsi_mid_low_api.txt
> 
> "
> ...
> /**
>  *      queuecommand - queue scsi command, invoke 'done' on completion
>  *      @scp: pointer to scsi command object
>  *      @done: function pointer to be invoked on completion
> ...
>  *
>  *      Returns 0 on success.
>  *
>  *      If there's a failure, return either:
>  *
>  *      SCSI_MLQUEUE_DEVICE_BUSY if the device queue is full, or
>  *      SCSI_MLQUEUE_HOST_BUSY if the entire host queue is full
>  *
>  *      On both of these returns, the mid-layer will requeue the I/O
> ...
> "
> 
> So the driver should set the if_busy flag to SCSI_MLQUEUE_DEVICE_BUSY or
> SCSI_MLQUEUE_HOST_BUSY (this is appropriate in this case) instead of setting
> it to 1, isn't it?
> 
> So, the following seems more appropriate
> 
> --- megaraid_mbox.c     2004-09-27 22:14:43.000000000 -0400
> +++ megaraid_mbox.c.mod 2004-11-19 12:15:21.776345776 -0500
> @@ -1675,7 +1675,7 @@
> 
>                         if (!(scb = megaraid_alloc_scb(adapter, scp))) {
>                                 scp->result = (DID_ERROR << 16);
> -                               *busy = 1;
> +                               *busy = SCSI_MLQUEUE_HOST_BUSY;
>                                 return NULL;
>                         }
> 

Nope doesn't work, only if you kill the done() call as well. non-zero
return will always trigger a requeue, which your SCSI done has alread
done. This is the bug.

-- 
Jens Axboe