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* [patch 17/17] drivers/scsi/device_handler/scsi_dh_emc.c: suppress warning
@ 2008-09-22 21:56 akpm
  2008-09-23 14:58 ` James Bottomley
  2008-10-14  7:33 ` Hannes Reinecke
  0 siblings, 2 replies; 4+ messages in thread
From: akpm @ 2008-09-22 21:56 UTC (permalink / raw)
  To: James.Bottomley; +Cc: linux-scsi, akpm, hare, schwidefsky

From: Andrew Morton <akpm@linux-foundation.org>

s390:

drivers/scsi/device_handler/scsi_dh_emc.c: In function 'parse_sp_info_reply':
drivers/scsi/device_handler/scsi_dh_emc.c:179: warning: comparison is always false due to limited range of data type

because chars are unsigned, I assume.

Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/scsi/device_handler/scsi_dh_emc.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff -puN drivers/scsi/device_handler/scsi_dh_emc.c~drivers-scsi-device_handler-scsi_dh_emcc-suppress-warning drivers/scsi/device_handler/scsi_dh_emc.c
--- a/drivers/scsi/device_handler/scsi_dh_emc.c~drivers-scsi-device_handler-scsi_dh_emcc-suppress-warning
+++ a/drivers/scsi/device_handler/scsi_dh_emc.c
@@ -176,7 +176,7 @@ static int parse_sp_info_reply(struct sc
 		err = SCSI_DH_DEV_TEMP_BUSY;
 		goto out;
 	}
-	if (csdev->buffer[4] < 0 || csdev->buffer[4] > 2) {
+	if (csdev->buffer[4] & ~3) {
 		/* Invalid buffer format */
 		sdev_printk(KERN_NOTICE, sdev,
 			    "%s: invalid VPD page 0xC0 format\n",
_

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [patch 17/17] drivers/scsi/device_handler/scsi_dh_emc.c: suppress warning
  2008-09-22 21:56 [patch 17/17] drivers/scsi/device_handler/scsi_dh_emc.c: suppress warning akpm
@ 2008-09-23 14:58 ` James Bottomley
  2008-09-23 17:50   ` Andrew Morton
  2008-10-14  7:33 ` Hannes Reinecke
  1 sibling, 1 reply; 4+ messages in thread
From: James Bottomley @ 2008-09-23 14:58 UTC (permalink / raw)
  To: akpm; +Cc: linux-scsi, hare, schwidefsky, Chandra Seetharaman

On Mon, 2008-09-22 at 14:56 -0700, akpm@linux-foundation.org wrote:
> From: Andrew Morton <akpm@linux-foundation.org>
> 
> s390:
> 
> drivers/scsi/device_handler/scsi_dh_emc.c: In function 'parse_sp_info_reply':
> drivers/scsi/device_handler/scsi_dh_emc.c:179: warning: comparison is always false due to limited range of data type
> 
> because chars are unsigned, I assume.

Actually, no, they're architecture implementation defined (another
cockup of the C standard) ... which must be why we don't see this on any
of the other architectures I compile on.

> Cc: Hannes Reinecke <hare@suse.de>
> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
> Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
> 
>  drivers/scsi/device_handler/scsi_dh_emc.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff -puN drivers/scsi/device_handler/scsi_dh_emc.c~drivers-scsi-device_handler-scsi_dh_emcc-suppress-warning drivers/scsi/device_handler/scsi_dh_emc.c
> --- a/drivers/scsi/device_handler/scsi_dh_emc.c~drivers-scsi-device_handler-scsi_dh_emcc-suppress-warning
> +++ a/drivers/scsi/device_handler/scsi_dh_emc.c
> @@ -176,7 +176,7 @@ static int parse_sp_info_reply(struct sc
>  		err = SCSI_DH_DEV_TEMP_BUSY;
>  		goto out;
>  	}
> -	if (csdev->buffer[4] < 0 || csdev->buffer[4] > 2) {
> +	if (csdev->buffer[4] & ~3) {

I'm afraid this isn't quite correct: ~3 will pass if csdev->buffer[4] ==
3 which is beyond the range of the original comparison.

How about this: it doesn't depend on the architecture to define the
signedness and it covers the original range?

James

---

diff --git a/drivers/scsi/device_handler/scsi_dh_emc.c b/drivers/scsi/device_handler/scsi_dh_emc.c
index ef693e8..a4055c4 100644
--- a/drivers/scsi/device_handler/scsi_dh_emc.c
+++ b/drivers/scsi/device_handler/scsi_dh_emc.c
@@ -84,7 +84,7 @@ struct clariion_dh_data {
 	/*
 	 * I/O buffer for both MODE_SELECT and INQUIRY commands.
 	 */
-	char buffer[CLARIION_BUFFER_SIZE];
+	unsigned char buffer[CLARIION_BUFFER_SIZE];
 	/*
 	 * SCSI sense buffer for commands -- assumes serial issuance
 	 * and completion sequence of all commands for same multipath.
@@ -176,7 +176,7 @@ static int parse_sp_info_reply(struct scsi_device *sdev,
 		err = SCSI_DH_DEV_TEMP_BUSY;
 		goto out;
 	}
-	if (csdev->buffer[4] < 0 || csdev->buffer[4] > 2) {
+	if (csdev->buffer[4] > 2) {
 		/* Invalid buffer format */
 		sdev_printk(KERN_NOTICE, sdev,
 			    "%s: invalid VPD page 0xC0 format\n",



^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [patch 17/17] drivers/scsi/device_handler/scsi_dh_emc.c: suppress warning
  2008-09-23 14:58 ` James Bottomley
@ 2008-09-23 17:50   ` Andrew Morton
  0 siblings, 0 replies; 4+ messages in thread
From: Andrew Morton @ 2008-09-23 17:50 UTC (permalink / raw)
  To: James Bottomley; +Cc: linux-scsi, hare, schwidefsky, Chandra Seetharaman

On Tue, 23 Sep 2008 07:58:59 -0700 James Bottomley <James.Bottomley@HansenPartnership.com> wrote:

> On Mon, 2008-09-22 at 14:56 -0700, akpm@linux-foundation.org wrote:
> > From: Andrew Morton <akpm@linux-foundation.org>
> > 
> > s390:
> > 
> > drivers/scsi/device_handler/scsi_dh_emc.c: In function 'parse_sp_info_reply':
> > drivers/scsi/device_handler/scsi_dh_emc.c:179: warning: comparison is always false due to limited range of data type
> > 
> > because chars are unsigned, I assume.
> 
> Actually, no, they're architecture implementation defined (another
> cockup of the C standard) ... which must be why we don't see this on any
> of the other architectures I compile on.

that's what I said ;)

> > Cc: Hannes Reinecke <hare@suse.de>
> > Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
> > Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
> > Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> > ---
> > 
> >  drivers/scsi/device_handler/scsi_dh_emc.c |    2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff -puN drivers/scsi/device_handler/scsi_dh_emc.c~drivers-scsi-device_handler-scsi_dh_emcc-suppress-warning drivers/scsi/device_handler/scsi_dh_emc.c
> > --- a/drivers/scsi/device_handler/scsi_dh_emc.c~drivers-scsi-device_handler-scsi_dh_emcc-suppress-warning
> > +++ a/drivers/scsi/device_handler/scsi_dh_emc.c
> > @@ -176,7 +176,7 @@ static int parse_sp_info_reply(struct sc
> >  		err = SCSI_DH_DEV_TEMP_BUSY;
> >  		goto out;
> >  	}
> > -	if (csdev->buffer[4] < 0 || csdev->buffer[4] > 2) {
> > +	if (csdev->buffer[4] & ~3) {
> 
> I'm afraid this isn't quite correct: ~3 will pass if csdev->buffer[4] ==
> 3 which is beyond the range of the original comparison.
> 
> How about this: it doesn't depend on the architecture to define the
> signedness and it covers the original range?
> 
> James
> 
> ---
> 
> diff --git a/drivers/scsi/device_handler/scsi_dh_emc.c b/drivers/scsi/device_handler/scsi_dh_emc.c
> index ef693e8..a4055c4 100644
> --- a/drivers/scsi/device_handler/scsi_dh_emc.c
> +++ b/drivers/scsi/device_handler/scsi_dh_emc.c
> @@ -84,7 +84,7 @@ struct clariion_dh_data {
>  	/*
>  	 * I/O buffer for both MODE_SELECT and INQUIRY commands.
>  	 */
> -	char buffer[CLARIION_BUFFER_SIZE];
> +	unsigned char buffer[CLARIION_BUFFER_SIZE];
>  	/*
>  	 * SCSI sense buffer for commands -- assumes serial issuance
>  	 * and completion sequence of all commands for same multipath.
> @@ -176,7 +176,7 @@ static int parse_sp_info_reply(struct scsi_device *sdev,
>  		err = SCSI_DH_DEV_TEMP_BUSY;
>  		goto out;
>  	}
> -	if (csdev->buffer[4] < 0 || csdev->buffer[4] > 2) {
> +	if (csdev->buffer[4] > 2) {
>  		/* Invalid buffer format */
>  		sdev_printk(KERN_NOTICE, sdev,
>  			    "%s: invalid VPD page 0xC0 format\n",
> 

looks good to me.


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [patch 17/17] drivers/scsi/device_handler/scsi_dh_emc.c: suppress warning
  2008-09-22 21:56 [patch 17/17] drivers/scsi/device_handler/scsi_dh_emc.c: suppress warning akpm
  2008-09-23 14:58 ` James Bottomley
@ 2008-10-14  7:33 ` Hannes Reinecke
  1 sibling, 0 replies; 4+ messages in thread
From: Hannes Reinecke @ 2008-10-14  7:33 UTC (permalink / raw)
  To: akpm; +Cc: James.Bottomley, linux-scsi, schwidefsky

Hi Andrew,

akpm@linux-foundation.org wrote:
> From: Andrew Morton <akpm@linux-foundation.org>
> 
> s390:
> 
> drivers/scsi/device_handler/scsi_dh_emc.c: In function 'parse_sp_info_reply':
> drivers/scsi/device_handler/scsi_dh_emc.c:179: warning: comparison is always false due to limited range of data type
> 
> because chars are unsigned, I assume.
> 
> Cc: Hannes Reinecke <hare@suse.de>
> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
> Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Hannes Reinecke <hare@suse.de>
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@suse.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Markus Rex, HRB 16746 (AG Nürnberg)
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^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2008-10-14  7:33 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2008-09-22 21:56 [patch 17/17] drivers/scsi/device_handler/scsi_dh_emc.c: suppress warning akpm
2008-09-23 14:58 ` James Bottomley
2008-09-23 17:50   ` Andrew Morton
2008-10-14  7:33 ` Hannes Reinecke

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