| Message ID | 20240105173920.1041474-1-leitao@debian.org (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next] net/ipv6: resolve warning in ip6_fib.c | expand |
On 1/5/24 10:39 AM, Breno Leitao wrote: > In some configurations, the 'iter' variable in function > fib6_repair_tree() is unused, resulting the following warning when > compiled with W=1. > > net/ipv6/ip6_fib.c:1781:6: warning: variable 'iter' set but not used [-Wunused-but-set-variable] > 1781 | int iter = 0; > | ^ > > Rewrite RT6_TRACE() macro to keep the variable in scope. > > Clang 18 removes the trace completely from the binary when the trace is > disabled[1], so, no overhead is expected with this change. > > [1] Link: https://paste.debian.net/1303162/ > > Signed-off-by: Breno Leitao <leitao@debian.org> > --- > include/net/ip6_fib.h | 6 +----- > 1 file changed, 1 insertion(+), 5 deletions(-) > > diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h > index 9ba6413fd2e3..d2ef60ebeb25 100644 > --- a/include/net/ip6_fib.h > +++ b/include/net/ip6_fib.h > @@ -30,11 +30,7 @@ > > #define RT6_DEBUG 2 > > -#if RT6_DEBUG >= 3 > -#define RT6_TRACE(x...) pr_debug(x) > -#else > -#define RT6_TRACE(x...) do { ; } while (0) > -#endif > +#define RT6_TRACE(x...) do { if (RT6_DEBUG > 3) pr_debug(x); } while (0) > > struct rt6_info; > struct fib6_info; I question the value of RT6_TRACE vs just using pr_debug; pr_debug has zero cost until enabled and can be enabled by file or line. Not requiring a kernel build is actual better. [cc'ed Wei who added the macro]
On Sat, Jan 06, 2024 at 09:13:53AM -0700, David Ahern wrote: > On 1/5/24 10:39 AM, Breno Leitao wrote: > > -#if RT6_DEBUG >= 3 > > -#define RT6_TRACE(x...) pr_debug(x) > > -#else > > -#define RT6_TRACE(x...) do { ; } while (0) > > -#endif > > +#define RT6_TRACE(x...) do { if (RT6_DEBUG > 3) pr_debug(x); } while (0) > > > > struct rt6_info; > > struct fib6_info; > > I question the value of RT6_TRACE vs just using pr_debug; pr_debug has > zero cost until enabled and can be enabled by file or line. Not > requiring a kernel build is actual better. > > [cc'ed Wei who added the macro] I also questioned it. Anyway, if we don't hear any strong opinion in favor of RT6_TRACE(), I will replace it by pr_debug() in a v2.
diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h index 9ba6413fd2e3..d2ef60ebeb25 100644 --- a/include/net/ip6_fib.h +++ b/include/net/ip6_fib.h @@ -30,11 +30,7 @@ #define RT6_DEBUG 2 -#if RT6_DEBUG >= 3 -#define RT6_TRACE(x...) pr_debug(x) -#else -#define RT6_TRACE(x...) do { ; } while (0) -#endif +#define RT6_TRACE(x...) do { if (RT6_DEBUG > 3) pr_debug(x); } while (0) struct rt6_info; struct fib6_info;
In some configurations, the 'iter' variable in function fib6_repair_tree() is unused, resulting the following warning when compiled with W=1. net/ipv6/ip6_fib.c:1781:6: warning: variable 'iter' set but not used [-Wunused-but-set-variable] 1781 | int iter = 0; | ^ Rewrite RT6_TRACE() macro to keep the variable in scope. Clang 18 removes the trace completely from the binary when the trace is disabled[1], so, no overhead is expected with this change. [1] Link: https://paste.debian.net/1303162/ Signed-off-by: Breno Leitao <leitao@debian.org> --- include/net/ip6_fib.h | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-)