| Message ID | 20200713080001.128044-25-lee.jones@linaro.org (mailing list archive) |
|---|---|
| State | Rejected |
| Headers | show |
| Series | Set 3: Fix another set of SCSI related W=1 warnings | expand |
On 7/13/20 10:00 AM, 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@suse.com> > Signed-off-by: Lee Jones <lee.jones@linaro.org> > --- > drivers/scsi/aic7xxx/aic79xx_osm.c | 4 ---- > 1 file changed, 4 deletions(-) > > diff --git a/drivers/scsi/aic7xxx/aic79xx_osm.c b/drivers/scsi/aic7xxx/aic79xx_osm.c > index 3782a20d58885..140c4e74ddd7e 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 +2237,6 @@ ahd_linux_queue_abort_cmd(struct scsi_cmnd *cmd) > goto done; > } > > - saved_modes = ahd_save_modes(ahd); > ahd_set_modes(ahd, AHD_MODE_SCSI, AHD_MODE_SCSI); > last_phase = ahd_inb(ahd, LASTPHASE); > saved_scbptr = ahd_get_scbptr(ahd); > @@ -2257,7 +2254,6 @@ 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); > if (last_phase != P_BUSFREE > && SCB_GET_TAG(pending_scb) == active_scbptr) { > > Reviewed-by: Hannes Reinecke <hare@suse.de> Cheers, Hannes
On Tue, 2020-07-14 at 09:46 +0200, Hannes Reinecke wrote: > On 7/13/20 10:00 AM, 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@suse.com> > > Signed-off-by: Lee Jones <lee.jones@linaro.org> > > --- > > drivers/scsi/aic7xxx/aic79xx_osm.c | 4 ---- > > 1 file changed, 4 deletions(-) > > > > diff --git a/drivers/scsi/aic7xxx/aic79xx_osm.c > > b/drivers/scsi/aic7xxx/aic79xx_osm.c > > index 3782a20d58885..140c4e74ddd7e 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 +2237,6 @@ ahd_linux_queue_abort_cmd(struct scsi_cmnd > > *cmd) > > goto done; > > } > > > > - saved_modes = ahd_save_modes(ahd); > > ahd_set_modes(ahd, AHD_MODE_SCSI, AHD_MODE_SCSI); > > last_phase = ahd_inb(ahd, LASTPHASE); > > saved_scbptr = ahd_get_scbptr(ahd); > > @@ -2257,7 +2254,6 @@ 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); > > if (last_phase != P_BUSFREE > > && SCB_GET_TAG(pending_scb) == active_scbptr) { > > > > > > Reviewed-by: Hannes Reinecke <hare@suse.de> Hey, you don't get to do that ... I asked you to figure out why we're missing an ahd_restore_modes(). Removing the ahd_save_modes() is cosmetic: it gets rid of a warning but doesn't fix the problem. I'd rather keep the warning until the problem is fixed and the problem is we need a mode save/restore around the ahd_set_modes() which is only partially implemented in this function. James
On Tue, 14 Jul 2020, James Bottomley wrote: > On Tue, 2020-07-14 at 09:46 +0200, Hannes Reinecke wrote: > > On 7/13/20 10:00 AM, 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@suse.com> > > > Signed-off-by: Lee Jones <lee.jones@linaro.org> > > > --- > > > drivers/scsi/aic7xxx/aic79xx_osm.c | 4 ---- > > > 1 file changed, 4 deletions(-) > > > > > > diff --git a/drivers/scsi/aic7xxx/aic79xx_osm.c > > > b/drivers/scsi/aic7xxx/aic79xx_osm.c > > > index 3782a20d58885..140c4e74ddd7e 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 +2237,6 @@ ahd_linux_queue_abort_cmd(struct scsi_cmnd > > > *cmd) > > > goto done; > > > } > > > > > > - saved_modes = ahd_save_modes(ahd); > > > ahd_set_modes(ahd, AHD_MODE_SCSI, AHD_MODE_SCSI); > > > last_phase = ahd_inb(ahd, LASTPHASE); > > > saved_scbptr = ahd_get_scbptr(ahd); > > > @@ -2257,7 +2254,6 @@ 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); > > > if (last_phase != P_BUSFREE > > > && SCB_GET_TAG(pending_scb) == active_scbptr) { > > > > > > > > > > Reviewed-by: Hannes Reinecke <hare@suse.de> > > Hey, you don't get to do that ... I asked you to figure out why we're > missing an ahd_restore_modes(). Removing the ahd_save_modes() is > cosmetic: it gets rid of a warning but doesn't fix the problem. I'd > rather keep the warning until the problem is fixed and the problem is > we need a mode save/restore around the ahd_set_modes() which is only > partially implemented in this function. I had a look. Traced it back to the dawn of time (time == Git), then delved even further back by downloading and trawling through ~10-15 tarballs. It looks as though drivers/scsi/aic7xxx/aic79xx_osm.c was upstreamed in v2.5.60, nearly 20 years ago. 'saved_modes' has been unused since at least then. If no one has complained in 2 decades, I'd say it probably isn't an issue worth perusing.
On Tue, 2020-07-14 at 22:39 +0100, Lee Jones wrote: > On Tue, 14 Jul 2020, James Bottomley wrote: > > > On Tue, 2020-07-14 at 09:46 +0200, Hannes Reinecke wrote: > > > On 7/13/20 10:00 AM, 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@suse.com> > > > > Signed-off-by: Lee Jones <lee.jones@linaro.org> > > > > --- > > > > drivers/scsi/aic7xxx/aic79xx_osm.c | 4 ---- > > > > 1 file changed, 4 deletions(-) > > > > > > > > diff --git a/drivers/scsi/aic7xxx/aic79xx_osm.c > > > > b/drivers/scsi/aic7xxx/aic79xx_osm.c > > > > index 3782a20d58885..140c4e74ddd7e 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 +2237,6 @@ ahd_linux_queue_abort_cmd(struct > > > > scsi_cmnd > > > > *cmd) > > > > goto done; > > > > } > > > > > > > > - saved_modes = ahd_save_modes(ahd); > > > > ahd_set_modes(ahd, AHD_MODE_SCSI, AHD_MODE_SCSI); > > > > last_phase = ahd_inb(ahd, LASTPHASE); > > > > saved_scbptr = ahd_get_scbptr(ahd); > > > > @@ -2257,7 +2254,6 @@ 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); > > > > if (last_phase != P_BUSFREE > > > > && SCB_GET_TAG(pending_scb) == active_scbptr) { > > > > > > > > > > > > > > Reviewed-by: Hannes Reinecke <hare@suse.de> > > > > Hey, you don't get to do that ... I asked you to figure out why > > we're missing an ahd_restore_modes(). Removing the > > ahd_save_modes() is cosmetic: it gets rid of a warning but doesn't > > fix the problem. I'd rather keep the warning until the problem is > > fixed and the problem is we need a mode save/restore around the > > ahd_set_modes() which is only partially implemented in this > > function. > > I had a look. Traced it back to the dawn of time (time == Git), then > delved even further back by downloading and trawling through ~10-15 > tarballs. It looks as though drivers/scsi/aic7xxx/aic79xx_osm.c was > upstreamed in v2.5.60, nearly 20 years ago. 'saved_modes' has been > unused since at least then. If no one has complained in 2 decades, > I'd say it probably isn't an issue worth perusing. Well, we have what looks like a fix now. The reason it matters is that if the bus is not in AHD_MODE_SCSI when the routine is called, it ends up being in a wrong state when the routine exits, so you abort one command and screw up another. Ultimately I bet escalation to bus reset fixes it, so everything appears to work, but it might have worked a lot better if the original mode were restored. This is error handling code, so most installations run just fine without ever invoking it. James
On 7/14/20 11:39 PM, Lee Jones wrote: > On Tue, 14 Jul 2020, James Bottomley wrote: > >> On Tue, 2020-07-14 at 09:46 +0200, Hannes Reinecke wrote: >>> On 7/13/20 10:00 AM, 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@suse.com> >>>> Signed-off-by: Lee Jones <lee.jones@linaro.org> >>>> --- >>>> drivers/scsi/aic7xxx/aic79xx_osm.c | 4 ---- >>>> 1 file changed, 4 deletions(-) >>>> >>>> diff --git a/drivers/scsi/aic7xxx/aic79xx_osm.c >>>> b/drivers/scsi/aic7xxx/aic79xx_osm.c >>>> index 3782a20d58885..140c4e74ddd7e 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 +2237,6 @@ ahd_linux_queue_abort_cmd(struct scsi_cmnd >>>> *cmd) >>>> goto done; >>>> } >>>> >>>> - saved_modes = ahd_save_modes(ahd); >>>> ahd_set_modes(ahd, AHD_MODE_SCSI, AHD_MODE_SCSI); >>>> last_phase = ahd_inb(ahd, LASTPHASE); >>>> saved_scbptr = ahd_get_scbptr(ahd); >>>> @@ -2257,7 +2254,6 @@ 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); >>>> if (last_phase != P_BUSFREE >>>> && SCB_GET_TAG(pending_scb) == active_scbptr) { >>>> >>>> >>> >>> Reviewed-by: Hannes Reinecke <hare@suse.de> >> >> Hey, you don't get to do that ... I asked you to figure out why we're >> missing an ahd_restore_modes(). Removing the ahd_save_modes() is >> cosmetic: it gets rid of a warning but doesn't fix the problem. I'd >> rather keep the warning until the problem is fixed and the problem is >> we need a mode save/restore around the ahd_set_modes() which is only >> partially implemented in this function. > > I had a look. Traced it back to the dawn of time (time == Git), then > delved even further back by downloading and trawling through ~10-15 > tarballs. It looks as though drivers/scsi/aic7xxx/aic79xx_osm.c was > upstreamed in v2.5.60, nearly 20 years ago. 'saved_modes' has been > unused since at least then. If no one has complained in 2 decades, > I'd say it probably isn't an issue worth perusing. > That's not really the point; this function is the first stage of error recovery. And the only real way of exercising this is to inject a command timeout, which is nearly impossible without dedicated hardware. So this function will have a very limited exposure, but nevertheless a quite crucial function. Hence I'm not quite agree with your reasoning, and rather would have it fixed. But as we're having an alternative fix now, it might be best if you could drop it from your patchset and we'll fix it separately. Cheers, Hannes
On Tue, 14 Jul 2020, James Bottomley wrote: > On Tue, 2020-07-14 at 22:39 +0100, Lee Jones wrote: > > On Tue, 14 Jul 2020, James Bottomley wrote: > > > > > On Tue, 2020-07-14 at 09:46 +0200, Hannes Reinecke wrote: > > > > On 7/13/20 10:00 AM, 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@suse.com> > > > > > Signed-off-by: Lee Jones <lee.jones@linaro.org> > > > > > --- > > > > > drivers/scsi/aic7xxx/aic79xx_osm.c | 4 ---- > > > > > 1 file changed, 4 deletions(-) > > > > > > > > > > diff --git a/drivers/scsi/aic7xxx/aic79xx_osm.c > > > > > b/drivers/scsi/aic7xxx/aic79xx_osm.c > > > > > index 3782a20d58885..140c4e74ddd7e 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 +2237,6 @@ ahd_linux_queue_abort_cmd(struct > > > > > scsi_cmnd > > > > > *cmd) > > > > > goto done; > > > > > } > > > > > > > > > > - saved_modes = ahd_save_modes(ahd); > > > > > ahd_set_modes(ahd, AHD_MODE_SCSI, AHD_MODE_SCSI); > > > > > last_phase = ahd_inb(ahd, LASTPHASE); > > > > > saved_scbptr = ahd_get_scbptr(ahd); > > > > > @@ -2257,7 +2254,6 @@ 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); > > > > > if (last_phase != P_BUSFREE > > > > > && SCB_GET_TAG(pending_scb) == active_scbptr) { > > > > > > > > > > > > > > > > > > Reviewed-by: Hannes Reinecke <hare@suse.de> > > > > > > Hey, you don't get to do that ... I asked you to figure out why > > > we're missing an ahd_restore_modes(). Removing the > > > ahd_save_modes() is cosmetic: it gets rid of a warning but doesn't > > > fix the problem. I'd rather keep the warning until the problem is > > > fixed and the problem is we need a mode save/restore around the > > > ahd_set_modes() which is only partially implemented in this > > > function. > > > > I had a look. Traced it back to the dawn of time (time == Git), then > > delved even further back by downloading and trawling through ~10-15 > > tarballs. It looks as though drivers/scsi/aic7xxx/aic79xx_osm.c was > > upstreamed in v2.5.60, nearly 20 years ago. 'saved_modes' has been > > unused since at least then. If no one has complained in 2 decades, > > I'd say it probably isn't an issue worth perusing. > > Well, we have what looks like a fix now. The reason it matters is that > if the bus is not in AHD_MODE_SCSI when the routine is called, it ends > up being in a wrong state when the routine exits, so you abort one > command and screw up another. Ultimately I bet escalation to bus reset > fixes it, so everything appears to work, but it might have worked a lot > better if the original mode were restored. > > This is error handling code, so most installations run just fine > without ever invoking it. Understood. Obviously a *real* fix is better than this warning suppression one. I was just explaining that, try as I might, I couldn't find any non-broken code to use to use as a reference to author a proper fix for this. This being the first mail in my inbox, so I don't know if the proper fix you reference above was a) sent as a patch and/or b) sent to me, but it's great news that you have one either way. Please drop this patch.
On Wed, 15 Jul 2020, Hannes Reinecke wrote: > On 7/14/20 11:39 PM, Lee Jones wrote: > > On Tue, 14 Jul 2020, James Bottomley wrote: > > > > > On Tue, 2020-07-14 at 09:46 +0200, Hannes Reinecke wrote: > > > > On 7/13/20 10:00 AM, 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@suse.com> > > > > > Signed-off-by: Lee Jones <lee.jones@linaro.org> > > > > > --- > > > > > drivers/scsi/aic7xxx/aic79xx_osm.c | 4 ---- > > > > > 1 file changed, 4 deletions(-) > > > > > > > > > > diff --git a/drivers/scsi/aic7xxx/aic79xx_osm.c > > > > > b/drivers/scsi/aic7xxx/aic79xx_osm.c > > > > > index 3782a20d58885..140c4e74ddd7e 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 +2237,6 @@ ahd_linux_queue_abort_cmd(struct scsi_cmnd > > > > > *cmd) > > > > > goto done; > > > > > } > > > > > - saved_modes = ahd_save_modes(ahd); > > > > > ahd_set_modes(ahd, AHD_MODE_SCSI, AHD_MODE_SCSI); > > > > > last_phase = ahd_inb(ahd, LASTPHASE); > > > > > saved_scbptr = ahd_get_scbptr(ahd); > > > > > @@ -2257,7 +2254,6 @@ 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); > > > > > if (last_phase != P_BUSFREE > > > > > && SCB_GET_TAG(pending_scb) == active_scbptr) { > > > > > > > > > > > > > Reviewed-by: Hannes Reinecke <hare@suse.de> > > > > > > Hey, you don't get to do that ... I asked you to figure out why we're > > > missing an ahd_restore_modes(). Removing the ahd_save_modes() is > > > cosmetic: it gets rid of a warning but doesn't fix the problem. I'd > > > rather keep the warning until the problem is fixed and the problem is > > > we need a mode save/restore around the ahd_set_modes() which is only > > > partially implemented in this function. > > > > I had a look. Traced it back to the dawn of time (time == Git), then > > delved even further back by downloading and trawling through ~10-15 > > tarballs. It looks as though drivers/scsi/aic7xxx/aic79xx_osm.c was > > upstreamed in v2.5.60, nearly 20 years ago. 'saved_modes' has been > > unused since at least then. If no one has complained in 2 decades, > > I'd say it probably isn't an issue worth perusing. > > > That's not really the point; this function is the first stage of error > recovery. And the only real way of exercising this is to inject a command > timeout, which is nearly impossible without dedicated hardware. > So this function will have a very limited exposure, but nevertheless a quite > crucial function. > Hence I'm not quite agree with your reasoning, and rather would have it > fixed. 100% agree. > But as we're having an alternative fix now, it might be best if you could > drop it from your patchset and we'll fix it separately. Sounds good. Thanks.
On 7/15/20 1:03 AM, James Bottomley wrote: > On Tue, 2020-07-14 at 22:39 +0100, Lee Jones wrote: >> On Tue, 14 Jul 2020, James Bottomley wrote: >> >>> On Tue, 2020-07-14 at 09:46 +0200, Hannes Reinecke wrote: >>>> On 7/13/20 10:00 AM, 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@suse.com> >>>>> Signed-off-by: Lee Jones <lee.jones@linaro.org> >>>>> --- >>>>> drivers/scsi/aic7xxx/aic79xx_osm.c | 4 ---- >>>>> 1 file changed, 4 deletions(-) >>>>> >>>>> diff --git a/drivers/scsi/aic7xxx/aic79xx_osm.c >>>>> b/drivers/scsi/aic7xxx/aic79xx_osm.c >>>>> index 3782a20d58885..140c4e74ddd7e 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 +2237,6 @@ ahd_linux_queue_abort_cmd(struct >>>>> scsi_cmnd >>>>> *cmd) >>>>> goto done; >>>>> } >>>>> >>>>> - saved_modes = ahd_save_modes(ahd); >>>>> ahd_set_modes(ahd, AHD_MODE_SCSI, AHD_MODE_SCSI); >>>>> last_phase = ahd_inb(ahd, LASTPHASE); >>>>> saved_scbptr = ahd_get_scbptr(ahd); >>>>> @@ -2257,7 +2254,6 @@ 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); >>>>> if (last_phase != P_BUSFREE >>>>> && SCB_GET_TAG(pending_scb) == active_scbptr) { >>>>> >>>>> >>>> >>>> Reviewed-by: Hannes Reinecke <hare@suse.de> >>> >>> Hey, you don't get to do that ... I asked you to figure out why >>> we're missing an ahd_restore_modes(). Removing the >>> ahd_save_modes() is cosmetic: it gets rid of a warning but doesn't >>> fix the problem. I'd rather keep the warning until the problem is >>> fixed and the problem is we need a mode save/restore around the >>> ahd_set_modes() which is only partially implemented in this >>> function. >> >> I had a look. Traced it back to the dawn of time (time == Git), then >> delved even further back by downloading and trawling through ~10-15 >> tarballs. It looks as though drivers/scsi/aic7xxx/aic79xx_osm.c was >> upstreamed in v2.5.60, nearly 20 years ago. 'saved_modes' has been >> unused since at least then. If no one has complained in 2 decades, >> I'd say it probably isn't an issue worth perusing. > > Well, we have what looks like a fix now. The reason it matters is that > if the bus is not in AHD_MODE_SCSI when the routine is called, it ends > up being in a wrong state when the routine exits, so you abort one > command and screw up another. Ultimately I bet escalation to bus reset > fixes it, so everything appears to work, but it might have worked a lot > better if the original mode were restored. > > This is error handling code, so most installations run just fine > without ever invoking it. > And since you mention it, it might also explain why every time this routine got invoked it failed to fixup anything and got escalated to bus reset. (And yes, I _did_ have some customer issues with aic79xx EH escalations over the years). Testing will be tricky, though, as you'd have to inject timeouts onto the parallel bus or device. Cheers, Hannes
diff --git a/drivers/scsi/aic7xxx/aic79xx_osm.c b/drivers/scsi/aic7xxx/aic79xx_osm.c index 3782a20d58885..140c4e74ddd7e 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 +2237,6 @@ ahd_linux_queue_abort_cmd(struct scsi_cmnd *cmd) goto done; } - saved_modes = ahd_save_modes(ahd); ahd_set_modes(ahd, AHD_MODE_SCSI, AHD_MODE_SCSI); last_phase = ahd_inb(ahd, LASTPHASE); saved_scbptr = ahd_get_scbptr(ahd); @@ -2257,7 +2254,6 @@ 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); if (last_phase != P_BUSFREE && SCB_GET_TAG(pending_scb) == active_scbptr) {
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@suse.com> Signed-off-by: Lee Jones <lee.jones@linaro.org> --- drivers/scsi/aic7xxx/aic79xx_osm.c | 4 ---- 1 file changed, 4 deletions(-)