Re: [PATCH] scsi: mpt3sas: fix hang on ata passthru commands

[James Bottomley]

On Tue, 2017-01-03 at 15:46 -0500, Jason Baron wrote:
> On 01/01/2017 12:39 PM, James Bottomley wrote:
> > +	/*
> > +	 * Bug work around for firmware SATL handling
> > +	 */
> > +	if (sas_device_priv_data->ata_command_pending) {
> > +		scmd->result = SAM_STAT_BUSY;
> > +		scmd->scsi_done(scmd);
> > +		return 0;
> > +	}
> > +	set_satl_pending(scmd, true);
> > +
> >  	sas_target_priv_data = sas_device_priv_data->sas_target;
> > 
> >  	/* invalid device handle */
> 
> 
> I was also wondering if 2 threads could both fall through and do:
> 'set_satl_pending(scmd, true)'; ?
> 
> Afaict there is nothing preventing that race?

Yes, it does look like queuecommand is lockless in the mpt3sas.  How
about this version using bitops for atomicity?

James

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