Re: [PATCH] Eliminate error handler overload of the SCSI serial number

[Mike Christie <michaelc@cs.wisc.edu>]

On 11/17/2010 10:10 AM, James Bottomley wrote:
> -static int scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
> -{
> -	/*
> -	 * scsi_done was called just after the command timed out and before
> -	 * we had a chance to process it. (db)
> -	 */
> -	if (scmd->serial_number == 0)
> -		return SUCCESS;
> -	return __scsi_try_to_abort_cmd(scmd);
> -}

Does it matter that with this patch we now call the driver's abort 
handler when the command has been added to the eh list when going 
through scsi_softirq_done-> scsi_decide_disposition returns FAILED -> 
scsi_eh_scmd_add?

It looks like most drivers will not send an abort, because they check 
something like the scsi_cmnd SCp pointer for their internal info and 
when it is not there they assume the command completed and just return 
(do some return FAILED and some return SUCCESS through). I did not check 
all drivers.

It seems like this is a really rare case that we get FAILED from 
scsi_decide_disposition so I thought it might not matter.