[PATCH] blackhole_dev: Fix buil warning

[PATCH] blackhole_dev: Fix buil warning

[Breno Leitao]

lib/test_blackhole_dev.c sets a variable that is never read, causing
this following building warning:

	lib/test_blackhole_dev.c:32:17: warning: variable 'ethh' set but not used [-Wunused-but-set-variable]

Remove the variable struct ethhdr *ethh, which is unused.

Fixes: 509e56b37cc3 ("blackhole_dev: add a selftest")
Signed-off-by: Breno Leitao <leitao@debian.org>
---
 lib/test_blackhole_dev.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/lib/test_blackhole_dev.c b/lib/test_blackhole_dev.c
index 4c40580a99a3..f247089d63c0 100644
--- a/lib/test_blackhole_dev.c
+++ b/lib/test_blackhole_dev.c
@@ -29,7 +29,6 @@ static int __init test_blackholedev_init(void)
 {
 	struct ipv6hdr *ip6h;
 	struct sk_buff *skb;
-	struct ethhdr *ethh;
 	struct udphdr *uh;
 	int data_len;
 	int ret;
@@ -61,7 +60,7 @@ static int __init test_blackholedev_init(void)
 	ip6h->saddr = in6addr_loopback;
 	ip6h->daddr = in6addr_loopback;
 	/* Ether */
-	ethh = (struct ethhdr *)skb_push(skb, sizeof(struct ethhdr));
+	skb_push(skb, sizeof(struct ethhdr));
 	skb_set_mac_header(skb, 0);
 
 	skb->protocol = htons(ETH_P_IPV6);
-- 
2.39.3

Re: [PATCH] blackhole_dev: Fix buil warning

[Jiri Pirko]

s/buil/build/ in the subject.

Also, indicate which tree are you targetting. In this case, should be:
[patch net-next] xxx


Thu, Feb 01, 2024 at 02:32:37PM CET, leitao@debian.org wrote:
>lib/test_blackhole_dev.c sets a variable that is never read, causing
>this following building warning:
>
>	lib/test_blackhole_dev.c:32:17: warning: variable 'ethh' set but not used [-Wunused-but-set-variable]
>
>Remove the variable struct ethhdr *ethh, which is unused.
>
>Fixes: 509e56b37cc3 ("blackhole_dev: add a selftest")
>Signed-off-by: Breno Leitao <leitao@debian.org>

The patch itself looks good. Feel free to attach
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
with the v2 with fixed subject. Thanks!


>---
> lib/test_blackhole_dev.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
>diff --git a/lib/test_blackhole_dev.c b/lib/test_blackhole_dev.c
>index 4c40580a99a3..f247089d63c0 100644
>--- a/lib/test_blackhole_dev.c
>+++ b/lib/test_blackhole_dev.c
>@@ -29,7 +29,6 @@ static int __init test_blackholedev_init(void)
> {
> 	struct ipv6hdr *ip6h;
> 	struct sk_buff *skb;
>-	struct ethhdr *ethh;
> 	struct udphdr *uh;
> 	int data_len;
> 	int ret;
>@@ -61,7 +60,7 @@ static int __init test_blackholedev_init(void)
> 	ip6h->saddr = in6addr_loopback;
> 	ip6h->daddr = in6addr_loopback;
> 	/* Ether */
>-	ethh = (struct ethhdr *)skb_push(skb, sizeof(struct ethhdr));
>+	skb_push(skb, sizeof(struct ethhdr));
> 	skb_set_mac_header(skb, 0);
> 
> 	skb->protocol = htons(ETH_P_IPV6);
>-- 
>2.39.3
>
>

Re: [PATCH] blackhole_dev: Fix buil warning

[Jakub Kicinski]

On Thu,  1 Feb 2024 05:32:37 -0800 Breno Leitao wrote:
> Subject: [PATCH] blackhole_dev: Fix buil warning

Since Jiri suggested a title fix I reckon we should be a bit more
specific, still. Imagine this title ending up in a quote or a Fixes
tag, could be many things.. How about:

  net: blackhole_dev: fix build warning for ethh set but not used

?

Re: [PATCH] blackhole_dev: Fix buil warning

[Breno Leitao]

On Thu, Feb 01, 2024 at 08:55:09AM -0800, Jakub Kicinski wrote:
> On Thu,  1 Feb 2024 05:32:37 -0800 Breno Leitao wrote:
> > Subject: [PATCH] blackhole_dev: Fix buil warning
> 
> Since Jiri suggested a title fix I reckon we should be a bit more
> specific, still. Imagine this title ending up in a quote or a Fixes
> tag, could be many things.. How about:
> 
>   net: blackhole_dev: fix build warning for ethh set but not used

Sure, let me resend it.

I suppose I should recent to `net` given it is a building warning,
right?

Re: [PATCH] blackhole_dev: Fix buil warning

[Jakub Kicinski]

On Thu, 1 Feb 2024 10:46:08 -0800 Breno Leitao wrote:
> > Since Jiri suggested a title fix I reckon we should be a bit more
> > specific, still. Imagine this title ending up in a quote or a Fixes
> > tag, could be many things.. How about:
> > 
> >   net: blackhole_dev: fix build warning for ethh set but not used  
> 
> Sure, let me resend it.
> 
> I suppose I should recent to `net` given it is a building warning,
> right?

Not necessarily, net-next is good enough for W=1 warnings in general.
Compiler warnings only show up if the file in question or some header
it includes was modified. The linker warnings are a bit special.
If you touch any file in any module you'll see all linker warnings.