[PATCH] mpt2sas: Fix &&/|| confusion in _scsih_sas_device_status_change_event()

[PATCH] mpt2sas: Fix &&/|| confusion in _scsih_sas_device_status_change_event()

[Roel Kluin]

This never evaluates to true.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
---
 drivers/scsi/mpt2sas/mpt2sas_scsih.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/scsi/mpt2sas/mpt2sas_scsih.c b/drivers/scsi/mpt2sas/mpt2sas_scsih.c
index efabea1..82c5474 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_scsih.c
+++ b/drivers/scsi/mpt2sas/mpt2sas_scsih.c
@@ -4363,7 +4363,7 @@ _scsih_sas_device_status_change_event(struct MPT2SAS_ADAPTER *ioc,
 #endif
 
 	if (!(event_data->ReasonCode ==
-	    MPI2_EVENT_SAS_DEV_STAT_RC_INTERNAL_DEVICE_RESET &&
+	    MPI2_EVENT_SAS_DEV_STAT_RC_INTERNAL_DEVICE_RESET ||
 	   event_data->ReasonCode ==
 	    MPI2_EVENT_SAS_DEV_STAT_RC_CMP_INTERNAL_DEV_RESET))
 		return;

RE: [PATCH] mpt2sas: Fix &&/|| confusion in _scsih_sas_device_status_change_event()

[Moore, Eric]

nack

The code beyond this check is intended for either INTERNAL_DEVICE_RESET or CMP_DEVICE_RESET.   If the reason code is something else, we will want to return.  There are 10 other types of reason codes besides these two. This proposed patch means we return only when the reason code is either INTERNAL_DEVICE_RESET or CMP_INTERNAL_RESET. 

Eric Moore

-----Original Message-----
From: linux-scsi-owner@vger.kernel.org [mailto:linux-scsi-owner@vger.kernel.org] On Behalf Of Roel Kluin
Sent: Wednesday, December 30, 2009 9:59 AM
To: James E.J. Bottomley; linux-scsi@vger.kernel.org; Andrew Morton; LKML; Desai, Kashyap
Subject: [PATCH] mpt2sas: Fix &&/|| confusion in _scsih_sas_device_status_change_event()

This never evaluates to true.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
---
 drivers/scsi/mpt2sas/mpt2sas_scsih.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/scsi/mpt2sas/mpt2sas_scsih.c b/drivers/scsi/mpt2sas/mpt2sas_scsih.c
index efabea1..82c5474 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_scsih.c
+++ b/drivers/scsi/mpt2sas/mpt2sas_scsih.c
@@ -4363,7 +4363,7 @@ _scsih_sas_device_status_change_event(struct MPT2SAS_ADAPTER *ioc,
 #endif
 
 	if (!(event_data->ReasonCode ==
-	    MPI2_EVENT_SAS_DEV_STAT_RC_INTERNAL_DEVICE_RESET &&
+	    MPI2_EVENT_SAS_DEV_STAT_RC_INTERNAL_DEVICE_RESET ||
 	   event_data->ReasonCode ==
 	    MPI2_EVENT_SAS_DEV_STAT_RC_CMP_INTERNAL_DEV_RESET))
 		return;
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Re: [PATCH] mpt2sas: Fix &&/|| confusion in _scsih_sas_device_status_change_event()

[roel kluin]

On Thu, Jan 7, 2010 at 8:31 PM, Moore, Eric <Eric.Moore@lsi.com> wrote:
> nack
>
> The code beyond this check is intended for either INTERNAL_DEVICE_RESET or CMP_DEVICE_RESET.   If the reason code is something else, we will want to return.  There are 10 other types of reason codes besides these two. This proposed patch means we return only when the reason code is either INTERNAL_DEVICE_RESET or CMP_INTERNAL_RESET.
>
> Eric Moore

my patch is correct but my changelog was wrong. Sorry for the
confusion. It should have been:

Even if the ReasonCode is not INTERNAL_DEVICE_RESET nor CMP_DEVICE_RESET
this still evaluates to true.

you can test this with:

#include <stdio.h>

int main()
{
        int d;
        for (d=0;d<4;++d)
                printf("!(%d == 1 && %d == 2) = %d\n", d, d, !(d == 1
&& d == 2));
        for (d=0;d<4;++d)
                printf("!(%d == 1 || %d == 2) = %d\n", d, d, !(d == 1
|| d == 2));
        return 0;
}

Roel

Re: [PATCH] mpt2sas: Fix &&/|| confusion in _scsih_sas_device_status_change_event()

[Andrew Morton]

On Thu, 7 Jan 2010 20:58:10 +0100
roel kluin <roel.kluin@gmail.com> wrote:

> On Thu, Jan 7, 2010 at 8:31 PM, Moore, Eric <Eric.Moore@lsi.com> wrote:
> > nack
> >
> > The code beyond this check is intended for either INTERNAL_DEVICE_RESET or CMP_DEVICE_RESET. __ If the reason code is something else, we will want to return. __There are 10 other types of reason codes besides these two. This proposed patch means we return only when the reason code is either INTERNAL_DEVICE_RESET or CMP_INTERNAL_RESET.
> >
> > Eric Moore
> 
> my patch is correct but my changelog was wrong. Sorry for the
> confusion. It should have been:
> 
> Even if the ReasonCode is not INTERNAL_DEVICE_RESET nor CMP_DEVICE_RESET
> this still evaluates to true.
> 

yup, the current code is wrong.

	if (!(event_data->ReasonCode ==
	    MPI2_EVENT_SAS_DEV_STAT_RC_INTERNAL_DEVICE_RESET &&
	   event_data->ReasonCode ==
	    MPI2_EVENT_SAS_DEV_STAT_RC_CMP_INTERNAL_DEV_RESET))
		return;

ReasonCode cannot equal two different things at the same time.

This is what we want:

	if (event_data->ReasonCode !=
	      MPI2_EVENT_SAS_DEV_STAT_RC_INTERNAL_DEVICE_RESET &&
	    event_data->ReasonCode !=
	      MPI2_EVENT_SAS_DEV_STAT_RC_CMP_INTERNAL_DEV_RESET)
		return;

Eric, the fix needs runtime testing please - it enables code which
hasn't been executed in a long time, if ever.

In fact the compiler wasn't even emitting any code for the second half
of _scsih_sas_device_status_change_event() because it worked out that
there was no path to it.

RE: [PATCH] mpt2sas: Fix &&/|| confusion in _scsih_sas_device_status_change_event()

[Moore, Eric]

Yes your patch will work.  I just have tested it by sending INTERNAL_DEVICE_RESETS events, and the code is getting executed.

Regards,
Eric

-----Original Message-----
From: Andrew Morton [mailto:akpm@linux-foundation.org] 
Sent: Tuesday, January 12, 2010 2:54 PM
To: roel kluin
Cc: Moore, Eric; James E.J. Bottomley; linux-scsi@vger.kernel.org; LKML; Desai, Kashyap
Subject: Re: [PATCH] mpt2sas: Fix &&/|| confusion in _scsih_sas_device_status_change_event()

On Thu, 7 Jan 2010 20:58:10 +0100
roel kluin <roel.kluin@gmail.com> wrote:

> On Thu, Jan 7, 2010 at 8:31 PM, Moore, Eric <Eric.Moore@lsi.com> wrote:
> > nack
> >
> > The code beyond this check is intended for either INTERNAL_DEVICE_RESET or CMP_DEVICE_RESET. __ If the reason code is something else, we will want to return. __There are 10 other types of reason codes besides these two. This proposed patch means we return only when the reason code is either INTERNAL_DEVICE_RESET or CMP_INTERNAL_RESET.
> >
> > Eric Moore
> 
> my patch is correct but my changelog was wrong. Sorry for the
> confusion. It should have been:
> 
> Even if the ReasonCode is not INTERNAL_DEVICE_RESET nor CMP_DEVICE_RESET
> this still evaluates to true.
> 

yup, the current code is wrong.

	if (!(event_data->ReasonCode ==
	    MPI2_EVENT_SAS_DEV_STAT_RC_INTERNAL_DEVICE_RESET &&
	   event_data->ReasonCode ==
	    MPI2_EVENT_SAS_DEV_STAT_RC_CMP_INTERNAL_DEV_RESET))
		return;

ReasonCode cannot equal two different things at the same time.

This is what we want:

	if (event_data->ReasonCode !=
	      MPI2_EVENT_SAS_DEV_STAT_RC_INTERNAL_DEVICE_RESET &&
	    event_data->ReasonCode !=
	      MPI2_EVENT_SAS_DEV_STAT_RC_CMP_INTERNAL_DEV_RESET)
		return;

Eric, the fix needs runtime testing please - it enables code which
hasn't been executed in a long time, if ever.

In fact the compiler wasn't even emitting any code for the second half
of _scsih_sas_device_status_change_event() because it worked out that
there was no path to it.

Re: [PATCH] mpt2sas: Fix &&/|| confusion in _scsih_sas_device_status_change_event()

[Andrew Morton]

On Tue, 12 Jan 2010 17:23:41 -0700
"Moore, Eric" <Eric.Moore@lsi.com> wrote:

> > -----Original Message-----
> > From: Andrew Morton [mailto:akpm@linux-foundation.org] 
> > Sent: Tuesday, January 12, 2010 2:54 PM
> > To: roel kluin
> > Cc: Moore, Eric; James E.J. Bottomley; linux-scsi@vger.kernel.org; LKML; Desai, Kashyap
> > Subject: Re: [PATCH] mpt2sas: Fix &&/|| confusion in _scsih_sas_device_status_change_event()
> > 
> > On Thu, 7 Jan 2010 20:58:10 +0100
> > roel kluin <roel.kluin@gmail.com> wrote:
> > 
> > > On Thu, Jan 7, 2010 at 8:31 PM, Moore, Eric <Eric.Moore@lsi.com> wrote:
> > > > nack
> > > >
> > > > The code beyond this check is intended for either INTERNAL_DEVICE_RESET or CMP_DEVICE_RESET. __ If the reason code is something else, we will want to return. __There are 10 other types of reason codes besides these two. This proposed patch means we return only when the reason code is either INTERNAL_DEVICE_RESET or CMP_INTERNAL_RESET.
> > > >
> > > > Eric Moore
> > > 
> > > my patch is correct but my changelog was wrong. Sorry for the
> > > confusion. It should have been:
> > > 
> > > Even if the ReasonCode is not INTERNAL_DEVICE_RESET nor CMP_DEVICE_RESET
> > > this still evaluates to true.
> > > 
> > 
> > yup, the current code is wrong.
> > 
> > 	if (!(event_data->ReasonCode ==
> > 	    MPI2_EVENT_SAS_DEV_STAT_RC_INTERNAL_DEVICE_RESET &&
> > 	   event_data->ReasonCode ==
> > 	    MPI2_EVENT_SAS_DEV_STAT_RC_CMP_INTERNAL_DEV_RESET))
> > 		return;
> > 
> > ReasonCode cannot equal two different things at the same time.
> > 
> > This is what we want:
> > 
> > 	if (event_data->ReasonCode !=
> > 	      MPI2_EVENT_SAS_DEV_STAT_RC_INTERNAL_DEVICE_RESET &&
> > 	    event_data->ReasonCode !=
> > 	      MPI2_EVENT_SAS_DEV_STAT_RC_CMP_INTERNAL_DEV_RESET)
> > 		return;
> > 
> > Eric, the fix needs runtime testing please - it enables code which
> > hasn't been executed in a long time, if ever.
> > 
> > In fact the compiler wasn't even emitting any code for the second half
> > of _scsih_sas_device_status_change_event() because it worked out that
> > there was no path to it.
> > 
>
> Yes your patch will work.  I just have tested it by sending INTERNAL_DEVICE_RESETS events, and the code is getting executed.
> 

(top-posting and quoting fixed)

Thanks.  Was that an ack to merge?

RE: [PATCH] mpt2sas: Fix &&/|| confusion in _scsih_sas_device_status_change_event()

[Moore, Eric]

>> Thanks.  Was that an ack to merge?

Yes, please merge in the code.  

ack