linux-kernel - Re: [PATCH 24/24] scsi: aic7xxx: aic79xx_osm: Remove set but unused variabes 'saved_scsiid' and 'saved

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Date:   Thu, 9 Jul 2020 20:30:55 +0100
From:   Lee Jones <lee.jones@...aro.org>
To:     James Bottomley <jejb@...ux.ibm.com>
Cc:     martin.petersen@...cle.com, linux-scsi@...r.kernel.org,
        linux-kernel@...r.kernel.org, Hannes Reinecke <hare@...e.com>
Subject: Re: [PATCH 24/24] scsi: aic7xxx: aic79xx_osm: Remove set but unused
 variabes 'saved_scsiid' and 'saved_modes'

On Thu, 09 Jul 2020, James Bottomley wrote:

> On Thu, 2020-07-09 at 18:45 +0100, Lee Jones wrote:
> > Haven't been used since 2006.
> > 
> > Fixes the following W=1 kernel build warning(s):
> > 
> >  drivers/scsi/aic7xxx/aic79xx_osm.c: In function
> > ‘ahd_linux_queue_abort_cmd’:
> >  drivers/scsi/aic7xxx/aic79xx_osm.c:2155:17: warning: variable
> > ‘saved_modes’ set but not used [-Wunused-but-set-variable]
> >  drivers/scsi/aic7xxx/aic79xx_osm.c:2148:9: warning: variable
> > ‘saved_scsiid’ set but not used [-Wunused-but-set-variable]
> > 
> > Cc: Hannes Reinecke <hare@...e.com>
> > Signed-off-by: Lee Jones <lee.jones@...aro.org>
> > ---
> >  drivers/scsi/aic7xxx/aic79xx_osm.c | 6 ++----
> >  1 file changed, 2 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/scsi/aic7xxx/aic79xx_osm.c
> > b/drivers/scsi/aic7xxx/aic79xx_osm.c
> > index 3782a20d58885..b0c6701f64a83 100644
> > --- a/drivers/scsi/aic7xxx/aic79xx_osm.c
> > +++ b/drivers/scsi/aic7xxx/aic79xx_osm.c
> > @@ -2141,14 +2141,12 @@ ahd_linux_queue_abort_cmd(struct scsi_cmnd
> > *cmd)
> >  	u_int  saved_scbptr;
> >  	u_int  active_scbptr;
> >  	u_int  last_phase;
> > -	u_int  saved_scsiid;
> >  	u_int  cdb_byte;
> >  	int    retval;
> >  	int    was_paused;
> >  	int    paused;
> >  	int    wait;
> >  	int    disconnected;
> > -	ahd_mode_state saved_modes;
> >  	unsigned long flags;
> >  
> >  	pending_scb = NULL;
> > @@ -2239,7 +2237,7 @@ ahd_linux_queue_abort_cmd(struct scsi_cmnd
> > *cmd)
> >  		goto done;
> >  	}
> >  
> > -	saved_modes = ahd_save_modes(ahd);
> > +	ahd_save_modes(ahd);
> 
> Well, this is clearly wrong, since ahd_save_modes has no side effects.

Great.  Thanks for letting me know.

I tend to err on the side of caution with these types of fix-ups.

I will remove it.

> However, I think it also means there's a bug in this code:
> 
> >  	ahd_set_modes(ahd, AHD_MODE_SCSI, AHD_MODE_SCSI);
> 
> You can't do this without later restoring the mode, so someone needs to
> figure out where the missing ahd_restore_modes() should go.
> 
> >  	last_phase = ahd_inb(ahd, LASTPHASE);
> >  	saved_scbptr = ahd_get_scbptr(ahd);
> > @@ -2257,7 +2255,7 @@ ahd_linux_queue_abort_cmd(struct scsi_cmnd
> > *cmd)
> >  	 * passed in command.  That command is currently active on
> > the
> >  	 * bus or is in the disconnected state.
> >  	 */
> > -	saved_scsiid = ahd_inb(ahd, SAVED_SCSIID);
> > +	ahd_inb(ahd, SAVED_SCSIID);
> 
> I think this can just go.

Happy to remove it also.

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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