[PATCH 15/19] sunrpc: don't warn for unused variable 'buf'

[PATCH 15/19] sunrpc: don't warn for unused variable 'buf'

[Arnd Bergmann]

When RPC_DEBUG is unset, the dprintk() macro does nothing,
causing the 'buf' variable in svc_printk to become unused.
Marking it as __maybe_unused avoids a harmless gcc warning.

Without this patch, building at91_dt_defconfig results in:

net/sunrpc/svc.c: In function 'svc_printk':
net/sunrpc/svc.c:1051:7: warning: unused variable 'buf' [-Wunused-variable]

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: "J. Bruce Fields" <bfields@redhat.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: linux-nfs@vger.kernel.org
Cc: netdev@vger.kernel.org
---
 net/sunrpc/svc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index dbf12ac..b1f5223 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1047,7 +1047,7 @@ void svc_printk(struct svc_rqst *rqstp, const char *fmt, ...)
 {
 	struct va_format vaf;
 	va_list args;
-	char 	buf[RPC_MAX_ADDRBUFLEN];
+	char buf[RPC_MAX_ADDRBUFLEN] __maybe_unused;
 
 	va_start(args, fmt);
 
-- 
1.8.0

[PATCH 15/19] sunrpc: don't warn for unused variable 'buf'

[Arnd Bergmann]

When RPC_DEBUG is unset, the dprintk() macro does nothing,
causing the 'buf' variable in svc_printk to become unused.
Marking it as __maybe_unused avoids a harmless gcc warning.

Without this patch, building at91_dt_defconfig results in:

net/sunrpc/svc.c: In function 'svc_printk':
net/sunrpc/svc.c:1051:7: warning: unused variable 'buf' [-Wunused-variable]

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: "J. Bruce Fields" <bfields@redhat.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: linux-nfs@vger.kernel.org
Cc: netdev@vger.kernel.org
---
 net/sunrpc/svc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index dbf12ac..b1f5223 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1047,7 +1047,7 @@ void svc_printk(struct svc_rqst *rqstp, const char *fmt, ...)
 {
 	struct va_format vaf;
 	va_list args;
-	char 	buf[RPC_MAX_ADDRBUFLEN];
+	char buf[RPC_MAX_ADDRBUFLEN] __maybe_unused;
 
 	va_start(args, fmt);
 
-- 
1.8.0

RE: [PATCH 15/19] sunrpc: don't warn for unused variable 'buf'

[Myklebust, Trond]

> -----Original Message-----
> From: Arnd Bergmann [mailto:arnd@arndb.de]
> Sent: Friday, January 25, 2013 5:44 PM
> To: linux-arm-kernel@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org; Arnd Bergmann; J. Bruce Fields;
> Myklebust, Trond; linux-nfs@vger.kernel.org; netdev@vger.kernel.org
> Subject: [PATCH 15/19] sunrpc: don't warn for unused variable 'buf'
> 
> When RPC_DEBUG is unset, the dprintk() macro does nothing, causing the
> 'buf' variable in svc_printk to become unused.
> Marking it as __maybe_unused avoids a harmless gcc warning.
> 
> Without this patch, building at91_dt_defconfig results in:
> 
> net/sunrpc/svc.c: In function 'svc_printk':
> net/sunrpc/svc.c:1051:7: warning: unused variable 'buf' [-Wunused-variable]
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Cc: "J. Bruce Fields" <bfields@redhat.com>
> Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
> Cc: linux-nfs@vger.kernel.org
> Cc: netdev@vger.kernel.org
> ---
>  net/sunrpc/svc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c index dbf12ac..b1f5223
> 100644
> --- a/net/sunrpc/svc.c
> +++ b/net/sunrpc/svc.c
> @@ -1047,7 +1047,7 @@ void svc_printk(struct svc_rqst *rqstp, const char
> *fmt, ...)  {
>  	struct va_format vaf;
>  	va_list args;
> -	char 	buf[RPC_MAX_ADDRBUFLEN];
> +	char buf[RPC_MAX_ADDRBUFLEN] __maybe_unused;
> 
>  	va_start(args, fmt);

Alternatively, just declare it using the RPC_IFDEBUG() macro.

Cheers
  Trond

Re: [PATCH 15/19] sunrpc: don't warn for unused variable 'buf'

[Arnd Bergmann]

On Friday 25 January 2013, Myklebust, Trond wrote:
> > -----Original Message-----
> > From: Arnd Bergmann [mailto:arnd@arndb.de]
> > Marking it as __maybe_unused avoids a harmless gcc warning.
> 
> Alternatively, just declare it using the RPC_IFDEBUG() macro.

Right, makes sense: that's more consistent with other functions
doing the same thing. Thanks for taking a look.

	Arnd

8<----

>From 3b2baeac061bd60dbf14bb61bcc03cbd64c85ac4 Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@arndb.de>
Date: Mon, 26 Nov 2012 22:46:26 +0000
Subject: [PATCH] sunrpc: don't warn for unused variable 'buf'

When RPC_DEBUG is unset, the dprintk() macro does nothing,
causing the 'buf' variable in svc_printk to become unused.
Enclosing it in RPC_IFDEBUG avoids a harmless gcc warning.

Without this patch, building at91_dt_defconfig results in:

net/sunrpc/svc.c: In function 'svc_printk':
net/sunrpc/svc.c:1051:7: warning: unused variable 'buf' [-Wunused-variable]

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: "J. Bruce Fields" <bfields@redhat.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: linux-nfs@vger.kernel.org
Cc: netdev@vger.kernel.org

diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index dbf12ac..9485e66 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1047,7 +1047,7 @@ void svc_printk(struct svc_rqst *rqstp, const char *fmt, ...)
 {
 	struct va_format vaf;
 	va_list args;
-	char 	buf[RPC_MAX_ADDRBUFLEN];
+	RPC_IFDEBUG(char buf[RPC_MAX_ADDRBUFLEN]);
 
 	va_start(args, fmt);
 

Re: [PATCH 15/19] sunrpc: don't warn for unused variable 'buf'

[Russell King - ARM Linux]

On Fri, Jan 25, 2013 at 11:45:25PM +0000, Arnd Bergmann wrote:
> On Friday 25 January 2013, Myklebust, Trond wrote:
> > > -----Original Message-----
> > > From: Arnd Bergmann [mailto:arnd@arndb.de]
> > > Marking it as __maybe_unused avoids a harmless gcc warning.
> > 
> > Alternatively, just declare it using the RPC_IFDEBUG() macro.
> 
> Right, makes sense: that's more consistent with other functions
> doing the same thing. Thanks for taking a look.

NAK.

There is already a fix queued up as a result of a previous report I
sent, but for some reason (which I didn't question) it was decided
not to queue it for -rc.

See Bruce's reply on lkml: 20130108212816.GA24572@fieldses.org

Re: [PATCH 15/19] sunrpc: don't warn for unused variable 'buf'

[Arnd Bergmann]

On Saturday 26 January 2013, Russell King - ARM Linux wrote:
> On Fri, Jan 25, 2013 at 11:45:25PM +0000, Arnd Bergmann wrote:
> > On Friday 25 January 2013, Myklebust, Trond wrote:
> > > > -----Original Message-----
> > > > From: Arnd Bergmann [mailto:arnd@arndb.de]
> > > > Marking it as __maybe_unused avoids a harmless gcc warning.
> > > 
> > > Alternatively, just declare it using the RPC_IFDEBUG() macro.
> > 
> > Right, makes sense: that's more consistent with other functions
> > doing the same thing. Thanks for taking a look.
> 
> NAK.
> 
> There is already a fix queued up as a result of a previous report I
> sent, but for some reason (which I didn't question) it was decided
> not to queue it for -rc.
> 
> See Bruce's reply on lkml: 20130108212816.GA24572@fieldses.org

Ok, makes sense. Then again, if that fix is queued for 3.9, maybe
it still makes sense to take the simpler fix into 3.8, and remove
it in 3.9 along with the other instances of RPC_IFDEBUG.

	Arnd

Re: [PATCH 15/19] sunrpc: don't warn for unused variable 'buf'

[J. Bruce Fields]

On Sat, Jan 26, 2013 at 01:34:56PM +0000, Arnd Bergmann wrote:
> On Saturday 26 January 2013, Russell King - ARM Linux wrote:
> > On Fri, Jan 25, 2013 at 11:45:25PM +0000, Arnd Bergmann wrote:
> > > On Friday 25 January 2013, Myklebust, Trond wrote:
> > > > > -----Original Message-----
> > > > > From: Arnd Bergmann [mailto:arnd@arndb.de]
> > > > > Marking it as __maybe_unused avoids a harmless gcc warning.
> > > > 
> > > > Alternatively, just declare it using the RPC_IFDEBUG() macro.
> > > 
> > > Right, makes sense: that's more consistent with other functions
> > > doing the same thing. Thanks for taking a look.
> > 
> > NAK.
> > 
> > There is already a fix queued up as a result of a previous report I
> > sent, but for some reason (which I didn't question) it was decided
> > not to queue it for -rc.
> > 
> > See Bruce's reply on lkml: 20130108212816.GA24572@fieldses.org

Apologies, I've seen so many "stop sending me post-rc1 patches that
don't fix serious crashes!" flames.

I guess obviousl compile fixes should be an exception--if nothing else
it'd save a lot of duplicated work as this is something like the 3rd
patch I've seen for this.

--b.

> 
> Ok, makes sense. Then again, if that fix is queued for 3.9, maybe
> it still makes sense to take the simpler fix into 3.8, and remove
> it in 3.9 along with the other instances of RPC_IFDEBUG.