[PATCH RESEND net-next 1/2] net/ipv6: Remove unnecessary pr_debug() logs

[PATCH RESEND net-next 1/2] net/ipv6: Remove unnecessary pr_debug() logs

[Breno Leitao]

In the ipv6 system, we have some logs basically dumping the name of the
function that is being called. This is not ideal, since ftrace give us
"for free". Moreover, checkpatch is not happy when touching that code:

	WARNING: Unnecessary ftrace-like logging - prefer using ftrace

Remove debug functions that only print the current function name.

Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
---
 net/ipv6/ip6_fib.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 4fc2cae0d116..fb41bec6b4b5 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -751,8 +751,6 @@ static struct fib6_node *fib6_add_1(struct net *net,
 	int	bit;
 	__be32	dir = 0;
 
-	RT6_TRACE("fib6_add_1\n");
-
 	/* insert node in tree */
 
 	fn = root;
@@ -1905,8 +1903,6 @@ static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn,
 	struct net *net = info->nl_net;
 	bool notify_del = false;
 
-	RT6_TRACE("fib6_del_route\n");
-
 	/* If the deleted route is the first in the node and it is not part of
 	 * a multipath route, then we need to replace it with the next route
 	 * in the node, if exists.
-- 
2.39.3

[PATCH RESEND net-next 2/2] net/ipv6: resolve warning in ip6_fib.c

[Breno Leitao]

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;
	  |             ^

It is unclear what is the advantage of this RT6_TRACE() macro[1], since
users can control pr_debug() in runtime, which is better than at
compilation time. pr_debug() has no overhead when disabled.

Remove the RT6_TRACE() in favor of simple pr_debug() helpers.

[1] Link: https://lore.kernel.org/all/ZZwSEJv2HgI0cD4J@gmail.com/
Signed-off-by: Breno Leitao <leitao@debian.org>
---
 include/net/ip6_fib.h |  6 ------
 net/ipv6/ip6_fib.c    | 15 +++++++++------
 net/ipv6/route.c      |  8 ++++----
 3 files changed, 13 insertions(+), 16 deletions(-)

diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index 9ba6413fd2e3..360b12e61850 100644
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -30,12 +30,6 @@
 
 #define RT6_DEBUG 2
 
-#if RT6_DEBUG >= 3
-#define RT6_TRACE(x...) pr_debug(x)
-#else
-#define RT6_TRACE(x...) do { ; } while (0)
-#endif
-
 struct rt6_info;
 struct fib6_info;
 
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index fb41bec6b4b5..38a0348b1d17 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -1801,7 +1801,7 @@ static struct fib6_node *fib6_repair_tree(struct net *net,
 					    lockdep_is_held(&table->tb6_lock));
 		struct fib6_info *new_fn_leaf;
 
-		RT6_TRACE("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
+		pr_debug("fixing tree: plen=%d iter=%d\n", fn->fn_bit, iter);
 		iter++;
 
 		WARN_ON(fn->fn_flags & RTN_RTINFO);
@@ -1864,7 +1864,8 @@ static struct fib6_node *fib6_repair_tree(struct net *net,
 		FOR_WALKERS(net, w) {
 			if (!child) {
 				if (w->node == fn) {
-					RT6_TRACE("W %p adjusted by delnode 1, s=%d/%d\n", w, w->state, nstate);
+					pr_debug("W %p adjusted by delnode 1, s=%d/%d\n",
+						 w, w->state, nstate);
 					w->node = pn;
 					w->state = nstate;
 				}
@@ -1872,10 +1873,12 @@ static struct fib6_node *fib6_repair_tree(struct net *net,
 				if (w->node == fn) {
 					w->node = child;
 					if (children&2) {
-						RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
+						pr_debug("W %p adjusted by delnode 2, s=%d\n",
+							 w, w->state);
 						w->state = w->state >= FWS_R ? FWS_U : FWS_INIT;
 					} else {
-						RT6_TRACE("W %p adjusted by delnode 2, s=%d\n", w, w->state);
+						pr_debug("W %p adjusted by delnode 2, s=%d\n",
+							 w, w->state);
 						w->state = w->state >= FWS_C ? FWS_U : FWS_INIT;
 					}
 				}
@@ -1951,7 +1954,7 @@ static void fib6_del_route(struct fib6_table *table, struct fib6_node *fn,
 	read_lock(&net->ipv6.fib6_walker_lock);
 	FOR_WALKERS(net, w) {
 		if (w->state == FWS_C && w->leaf == rt) {
-			RT6_TRACE("walker %p adjusted by delroute\n", w);
+			pr_debug("walker %p adjusted by delroute\n", w);
 			w->leaf = rcu_dereference_protected(rt->fib6_next,
 					    lockdep_is_held(&table->tb6_lock));
 			if (!w->leaf)
@@ -2289,7 +2292,7 @@ static int fib6_age(struct fib6_info *rt, void *arg)
 
 	if (rt->fib6_flags & RTF_EXPIRES && rt->expires) {
 		if (time_after(now, rt->expires)) {
-			RT6_TRACE("expiring %p\n", rt);
+			pr_debug("expiring %p\n", rt);
 			return -1;
 		}
 		gc_args->more++;
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index ea1dec8448fc..63b4c6056582 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2085,12 +2085,12 @@ static void rt6_age_examine_exception(struct rt6_exception_bucket *bucket,
 	 */
 	if (!(rt->rt6i_flags & RTF_EXPIRES)) {
 		if (time_after_eq(now, rt->dst.lastuse + gc_args->timeout)) {
-			RT6_TRACE("aging clone %p\n", rt);
+			pr_debug("aging clone %p\n", rt);
 			rt6_remove_exception(bucket, rt6_ex);
 			return;
 		}
 	} else if (time_after(jiffies, rt->dst.expires)) {
-		RT6_TRACE("purging expired route %p\n", rt);
+		pr_debug("purging expired route %p\n", rt);
 		rt6_remove_exception(bucket, rt6_ex);
 		return;
 	}
@@ -2101,8 +2101,8 @@ static void rt6_age_examine_exception(struct rt6_exception_bucket *bucket,
 		neigh = __ipv6_neigh_lookup_noref(rt->dst.dev, &rt->rt6i_gateway);
 
 		if (!(neigh && (neigh->flags & NTF_ROUTER))) {
-			RT6_TRACE("purging route %p via non-router but gateway\n",
-				  rt);
+			pr_debug("purging route %p via non-router but gateway\n",
+				 rt);
 			rt6_remove_exception(bucket, rt6_ex);
 			return;
 		}
-- 
2.39.3

Re: [PATCH RESEND net-next 2/2] net/ipv6: resolve warning in ip6_fib.c

[David Ahern]

On 1/22/24 11:19 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;
> 	  |             ^
> 
> It is unclear what is the advantage of this RT6_TRACE() macro[1], since
> users can control pr_debug() in runtime, which is better than at
> compilation time. pr_debug() has no overhead when disabled.
> 
> Remove the RT6_TRACE() in favor of simple pr_debug() helpers.
> 
> [1] Link: https://lore.kernel.org/all/ZZwSEJv2HgI0cD4J@gmail.com/
> Signed-off-by: Breno Leitao <leitao@debian.org>
> ---
>  include/net/ip6_fib.h |  6 ------
>  net/ipv6/ip6_fib.c    | 15 +++++++++------
>  net/ipv6/route.c      |  8 ++++----
>  3 files changed, 13 insertions(+), 16 deletions(-)
> 

Reviewed-by: David Ahern <dsahern@kernel.org>

Re: [PATCH RESEND net-next 1/2] net/ipv6: Remove unnecessary pr_debug() logs

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Mon, 22 Jan 2024 10:19:54 -0800 you wrote:
> In the ipv6 system, we have some logs basically dumping the name of the
> function that is being called. This is not ideal, since ftrace give us
> "for free". Moreover, checkpatch is not happy when touching that code:
> 
> 	WARNING: Unnecessary ftrace-like logging - prefer using ftrace
> 
> Remove debug functions that only print the current function name.
> 
> [...]

Here is the summary with links:
  - [RESEND,net-next,1/2] net/ipv6: Remove unnecessary pr_debug() logs
    https://git.kernel.org/netdev/net-next/c/a6348a7104e0
  - [RESEND,net-next,2/2] net/ipv6: resolve warning in ip6_fib.c
    https://git.kernel.org/netdev/net-next/c/20df28fb5bd8

You are awesome, thank you!
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