[PATCH] net/xdp: remove unused macro REG_STATE_NEW

[PATCH] net/xdp: remove unused macro REG_STATE_NEW

[Alex Shi]

To tame gcc warning on it:
net/core/xdp.c:20:0: warning: macro "REG_STATE_NEW" is not used
[-Wunused-macros]

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: "David S. Miller" <davem@davemloft.net> 
Cc: Jakub Kicinski <kuba@kernel.org> 
Cc: Alexei Starovoitov <ast@kernel.org> 
Cc: Daniel Borkmann <daniel@iogearbox.net> 
Cc: Jesper Dangaard Brouer <hawk@kernel.org> 
Cc: John Fastabend <john.fastabend@gmail.com> 
Cc: netdev@vger.kernel.org 
Cc: bpf@vger.kernel.org 
Cc: linux-kernel@vger.kernel.org 
---
 net/core/xdp.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/net/core/xdp.c b/net/core/xdp.c
index 48aba933a5a8..3d88aab19c89 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -19,7 +19,6 @@
 #include <trace/events/xdp.h>
 #include <net/xdp_sock_drv.h>
 
-#define REG_STATE_NEW		0x0
 #define REG_STATE_REGISTERED	0x1
 #define REG_STATE_UNREGISTERED	0x2
 #define REG_STATE_UNUSED	0x3
-- 
1.8.3.1

Re: [PATCH] net/xdp: remove unused macro REG_STATE_NEW

[Jesper Dangaard Brouer]

On Fri,  6 Nov 2020 13:43:51 +0800
Alex Shi <alex.shi@linux.alibaba.com> wrote:

> To tame gcc warning on it:
> net/core/xdp.c:20:0: warning: macro "REG_STATE_NEW" is not used
> [-Wunused-macros]

Hmm... REG_STATE_NEW is zero, so it is implicitly set via memset zero.
But it is true that it is technically not directly used or referenced.

It is mentioned in a comment, so please send V2 with this additional change:

$ git diff
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 48aba933a5a8..6e1430971ac2 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -175,7 +175,7 @@ int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
                return -ENODEV;
        }
 
-       /* State either UNREGISTERED or NEW */
+       /* State either UNREGISTERED or zero */
        xdp_rxq_info_init(xdp_rxq);
        xdp_rxq->dev = dev;
        xdp_rxq->queue_index = queue_index;


> Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
> Cc: "David S. Miller" <davem@davemloft.net> 
> Cc: Jakub Kicinski <kuba@kernel.org> 
> Cc: Alexei Starovoitov <ast@kernel.org> 
> Cc: Daniel Borkmann <daniel@iogearbox.net> 
> Cc: Jesper Dangaard Brouer <hawk@kernel.org> 
> Cc: John Fastabend <john.fastabend@gmail.com> 
> Cc: netdev@vger.kernel.org 
> Cc: bpf@vger.kernel.org 
> Cc: linux-kernel@vger.kernel.org 
> ---
>  net/core/xdp.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/net/core/xdp.c b/net/core/xdp.c
> index 48aba933a5a8..3d88aab19c89 100644
> --- a/net/core/xdp.c
> +++ b/net/core/xdp.c
> @@ -19,7 +19,6 @@
>  #include <trace/events/xdp.h>
>  #include <net/xdp_sock_drv.h>
>  
> -#define REG_STATE_NEW		0x0
>  #define REG_STATE_REGISTERED	0x1
>  #define REG_STATE_UNREGISTERED	0x2
>  #define REG_STATE_UNUSED	0x3



-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer

Re: [PATCH] net/xdp: remove unused macro REG_STATE_NEW

[Alex Shi]

在 2020/11/7 上午12:13, Jesper Dangaard Brouer 写道:
> Hmm... REG_STATE_NEW is zero, so it is implicitly set via memset zero.
> But it is true that it is technically not directly used or referenced.
> 
> It is mentioned in a comment, so please send V2 with this additional change:

Hi Jesper,

Thanks a lot for comments. here is the v2:

From 2908d25bf2e1c90ad71a83ba056743f45da283e8 Mon Sep 17 00:00:00 2001
From: Alex Shi <alex.shi@linux.alibaba.com>
Date: Fri, 6 Nov 2020 13:41:58 +0800
Subject: [PATCH v2] net/xdp: remove unused macro REG_STATE_NEW

To tame gcc warning on it:
net/core/xdp.c:20:0: warning: macro "REG_STATE_NEW" is not used
[-Wunused-macros]
And change related comments as Jesper Dangaard Brouer suggested.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
---
 net/core/xdp.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/core/xdp.c b/net/core/xdp.c
index 48aba933a5a8..0df5ee5682d9 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -19,7 +19,6 @@
 #include <trace/events/xdp.h>
 #include <net/xdp_sock_drv.h>
 
-#define REG_STATE_NEW		0x0
 #define REG_STATE_REGISTERED	0x1
 #define REG_STATE_UNREGISTERED	0x2
 #define REG_STATE_UNUSED	0x3
@@ -175,7 +174,7 @@ int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
 		return -ENODEV;
 	}
 
-	/* State either UNREGISTERED or NEW */
+	/* State either UNREGISTERED or zero */
 	xdp_rxq_info_init(xdp_rxq);
 	xdp_rxq->dev = dev;
 	xdp_rxq->queue_index = queue_index;
-- 
1.8.3.1

Re: [PATCH] net/xdp: remove unused macro REG_STATE_NEW

[John Fastabend]

Alex Shi wrote:
> 
> 
> 在 2020/11/7 上午12:13, Jesper Dangaard Brouer 写道:
> > Hmm... REG_STATE_NEW is zero, so it is implicitly set via memset zero.
> > But it is true that it is technically not directly used or referenced.
> > 
> > It is mentioned in a comment, so please send V2 with this additional change:
> 
> Hi Jesper,
> 
> Thanks a lot for comments. here is the v2:
> 
> From 2908d25bf2e1c90ad71a83ba056743f45da283e8 Mon Sep 17 00:00:00 2001
> From: Alex Shi <alex.shi@linux.alibaba.com>
> Date: Fri, 6 Nov 2020 13:41:58 +0800
> Subject: [PATCH v2] net/xdp: remove unused macro REG_STATE_NEW
> 
> To tame gcc warning on it:
> net/core/xdp.c:20:0: warning: macro "REG_STATE_NEW" is not used
> [-Wunused-macros]
> And change related comments as Jesper Dangaard Brouer suggested.
> 
> Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
> ---

>  net/core/xdp.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/net/core/xdp.c b/net/core/xdp.c
> index 48aba933a5a8..0df5ee5682d9 100644
> --- a/net/core/xdp.c
> +++ b/net/core/xdp.c
> @@ -19,7 +19,6 @@
>  #include <trace/events/xdp.h>
>  #include <net/xdp_sock_drv.h>
>  
> -#define REG_STATE_NEW		0x0
>  #define REG_STATE_REGISTERED	0x1
>  #define REG_STATE_UNREGISTERED	0x2
>  #define REG_STATE_UNUSED	0x3

I think having the define there makes it more readable and clear what
the zero state is. But if we run with unused-macros I guess its even
uglier to try and mark it with unused attribute.

Acked-by: John Fastabend <john.fastabend@gmail.com>

> @@ -175,7 +174,7 @@ int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
>  		return -ENODEV;
>  	}
>  
> -	/* State either UNREGISTERED or NEW */
> +	/* State either UNREGISTERED or zero */
>  	xdp_rxq_info_init(xdp_rxq);
>  	xdp_rxq->dev = dev;
>  	xdp_rxq->queue_index = queue_index;
> -- 
> 1.8.3.1
> 

Re: [PATCH] net/xdp: remove unused macro REG_STATE_NEW

[Jesper Dangaard Brouer]

On Mon, 09 Nov 2020 13:44:48 -0800
John Fastabend <john.fastabend@gmail.com> wrote:

> Alex Shi wrote:
> > 
> > 
> > 在 2020/11/7 上午12:13, Jesper Dangaard Brouer 写道:  
> > > Hmm... REG_STATE_NEW is zero, so it is implicitly set via memset zero.
> > > But it is true that it is technically not directly used or referenced.
> > > 
> > > It is mentioned in a comment, so please send V2 with this additional change:  
> > 
> > Hi Jesper,
> > 
> > Thanks a lot for comments. here is the v2:
> > 
> > From 2908d25bf2e1c90ad71a83ba056743f45da283e8 Mon Sep 17 00:00:00 2001
> > From: Alex Shi <alex.shi@linux.alibaba.com>
> > Date: Fri, 6 Nov 2020 13:41:58 +0800
> > Subject: [PATCH v2] net/xdp: remove unused macro REG_STATE_NEW
> > 
> > To tame gcc warning on it:
> > net/core/xdp.c:20:0: warning: macro "REG_STATE_NEW" is not used
> > [-Wunused-macros]
> > And change related comments as Jesper Dangaard Brouer suggested.
> > 
> > Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
> > ---  
> 
> >  net/core/xdp.c | 3 +--
> >  1 file changed, 1 insertion(+), 2 deletions(-)
> > 
> > diff --git a/net/core/xdp.c b/net/core/xdp.c
> > index 48aba933a5a8..0df5ee5682d9 100644
> > --- a/net/core/xdp.c
> > +++ b/net/core/xdp.c
> > @@ -19,7 +19,6 @@
> >  #include <trace/events/xdp.h>
> >  #include <net/xdp_sock_drv.h>
> >  
> > -#define REG_STATE_NEW		0x0
> >  #define REG_STATE_REGISTERED	0x1
> >  #define REG_STATE_UNREGISTERED	0x2
> >  #define REG_STATE_UNUSED	0x3  
> 
> I think having the define there makes it more readable and clear what
> the zero state is. But if we run with unused-macros I guess its even
> uglier to try and mark it with unused attribute.

I  agree having the define there makes it more readable and clear what
the zero state is.

We can also add code that replace the comment, that check/use these
defines.  It is slow-path code, so it doesn't hurt to add this extra
code.  Generally I find it strange to "fix" these kind of warnings, but
also don't care that we do fix them if it helps someone else spot code
where it actually matters.

> Acked-by: John Fastabend <john.fastabend@gmail.com>
> 
> > @@ -175,7 +174,7 @@ int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
> >  		return -ENODEV;
> >  	}
> >  
> > -	/* State either UNREGISTERED or NEW */
> > +	/* State either UNREGISTERED or zero */
> >  	xdp_rxq_info_init(xdp_rxq);
> >  	xdp_rxq->dev = dev;
> >  	xdp_rxq->queue_index = queue_index;
> > -- 
> > 1.8.3.1
> >   
> 
> 



-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer