[PATCH net-next] net: ipv6: use the new fib6_nh_release_dsts helper in fib6_nh_release

[PATCH net-next] net: ipv6: use the new fib6_nh_release_dsts helper in fib6_nh_release

[Nikolay Aleksandrov]

From: Nikolay Aleksandrov <nikolay@nvidia.com>

We can remove a bit of code duplication by reusing the new
fib6_nh_release_dsts helper in fib6_nh_release. Their only difference is
that fib6_nh_release's version doesn't use atomic operation to swap the
pointers because it assumes the fib6_nh is no longer visible, while
fib6_nh_release_dsts can be used anywhere.

Suggested-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
---
 net/ipv6/route.c | 19 ++-----------------
 1 file changed, 2 insertions(+), 17 deletions(-)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 62f1e16eea2b..b44438b9a030 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -3656,24 +3656,9 @@ void fib6_nh_release(struct fib6_nh *fib6_nh)
 
 	rcu_read_unlock();
 
-	if (fib6_nh->rt6i_pcpu) {
-		int cpu;
-
-		for_each_possible_cpu(cpu) {
-			struct rt6_info **ppcpu_rt;
-			struct rt6_info *pcpu_rt;
-
-			ppcpu_rt = per_cpu_ptr(fib6_nh->rt6i_pcpu, cpu);
-			pcpu_rt = *ppcpu_rt;
-			if (pcpu_rt) {
-				dst_dev_put(&pcpu_rt->dst);
-				dst_release(&pcpu_rt->dst);
-				*ppcpu_rt = NULL;
-			}
-		}
-
+	fib6_nh_release_dsts(fib6_nh);
+	if (fib6_nh->rt6i_pcpu)
 		free_percpu(fib6_nh->rt6i_pcpu);
-	}
 
 	fib_nh_common_release(&fib6_nh->nh_common);
 }
-- 
2.31.1

Re: [PATCH net-next] net: ipv6: use the new fib6_nh_release_dsts helper in fib6_nh_release

[Nikolay Aleksandrov]

On 29/11/2021 14:09, Nikolay Aleksandrov wrote:
> From: Nikolay Aleksandrov <nikolay@nvidia.com>
> 
> We can remove a bit of code duplication by reusing the new
> fib6_nh_release_dsts helper in fib6_nh_release. Their only difference is
> that fib6_nh_release's version doesn't use atomic operation to swap the
> pointers because it assumes the fib6_nh is no longer visible, while
> fib6_nh_release_dsts can be used anywhere.
> 
> Suggested-by: David Ahern <dsahern@gmail.com>
> Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
> ---
>  net/ipv6/route.c | 19 ++-----------------
>  1 file changed, 2 insertions(+), 17 deletions(-)
> 
> diff --git a/net/ipv6/route.c b/net/ipv6/route.c
> index 62f1e16eea2b..b44438b9a030 100644
> --- a/net/ipv6/route.c
> +++ b/net/ipv6/route.c
> @@ -3656,24 +3656,9 @@ void fib6_nh_release(struct fib6_nh *fib6_nh)
>  
>  	rcu_read_unlock();
>  
> -	if (fib6_nh->rt6i_pcpu) {
> -		int cpu;
> -
> -		for_each_possible_cpu(cpu) {
> -			struct rt6_info **ppcpu_rt;
> -			struct rt6_info *pcpu_rt;
> -
> -			ppcpu_rt = per_cpu_ptr(fib6_nh->rt6i_pcpu, cpu);
> -			pcpu_rt = *ppcpu_rt;
> -			if (pcpu_rt) {
> -				dst_dev_put(&pcpu_rt->dst);
> -				dst_release(&pcpu_rt->dst);
> -				*ppcpu_rt = NULL;
> -			}
> -		}
> -
> +	fib6_nh_release_dsts(fib6_nh);
> +	if (fib6_nh->rt6i_pcpu)

Actually I can even drop the conditional here, free_percpu() is a noop
if called with NULL. Will respin in a few..

[PATCH net-next v2] net: ipv6: use the new fib6_nh_release_dsts helper in fib6_nh_release

[Nikolay Aleksandrov]

From: Nikolay Aleksandrov <nikolay@nvidia.com>

We can remove a bit of code duplication by reusing the new
fib6_nh_release_dsts helper in fib6_nh_release. Their only difference is
that fib6_nh_release's version doesn't use atomic operation to swap the
pointers because it assumes the fib6_nh is no longer visible, while
fib6_nh_release_dsts can be used anywhere.

Suggested-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
---
v2: no need to check for NULL rt6i_pcpu before calling free_percpu

 net/ipv6/route.c | 20 ++------------------
 1 file changed, 2 insertions(+), 18 deletions(-)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 62f1e16eea2b..f0d29fcb2094 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -3656,24 +3656,8 @@ void fib6_nh_release(struct fib6_nh *fib6_nh)
 
 	rcu_read_unlock();
 
-	if (fib6_nh->rt6i_pcpu) {
-		int cpu;
-
-		for_each_possible_cpu(cpu) {
-			struct rt6_info **ppcpu_rt;
-			struct rt6_info *pcpu_rt;
-
-			ppcpu_rt = per_cpu_ptr(fib6_nh->rt6i_pcpu, cpu);
-			pcpu_rt = *ppcpu_rt;
-			if (pcpu_rt) {
-				dst_dev_put(&pcpu_rt->dst);
-				dst_release(&pcpu_rt->dst);
-				*ppcpu_rt = NULL;
-			}
-		}
-
-		free_percpu(fib6_nh->rt6i_pcpu);
-	}
+	fib6_nh_release_dsts(fib6_nh);
+	free_percpu(fib6_nh->rt6i_pcpu);
 
 	fib_nh_common_release(&fib6_nh->nh_common);
 }
-- 
2.31.1

Re: [PATCH net-next v2] net: ipv6: use the new fib6_nh_release_dsts helper in fib6_nh_release

[David Ahern]

On 11/29/21 8:44 AM, Nikolay Aleksandrov wrote:
> From: Nikolay Aleksandrov <nikolay@nvidia.com>
> 
> We can remove a bit of code duplication by reusing the new
> fib6_nh_release_dsts helper in fib6_nh_release. Their only difference is
> that fib6_nh_release's version doesn't use atomic operation to swap the
> pointers because it assumes the fib6_nh is no longer visible, while
> fib6_nh_release_dsts can be used anywhere.
> 
> Suggested-by: David Ahern <dsahern@gmail.com>
> Signed-off-by: Nikolay Aleksandrov <nikolay@nvidia.com>
> ---
> v2: no need to check for NULL rt6i_pcpu before calling free_percpu
> 
>  net/ipv6/route.c | 20 ++------------------
>  1 file changed, 2 insertions(+), 18 deletions(-)
> 



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

Re: [PATCH net-next v2] net: ipv6: use the new fib6_nh_release_dsts helper in fib6_nh_release

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (master)
by David S. Miller <davem@davemloft.net>:

On Mon, 29 Nov 2021 17:44:11 +0200 you wrote:
> From: Nikolay Aleksandrov <nikolay@nvidia.com>
> 
> We can remove a bit of code duplication by reusing the new
> fib6_nh_release_dsts helper in fib6_nh_release. Their only difference is
> that fib6_nh_release's version doesn't use atomic operation to swap the
> pointers because it assumes the fib6_nh is no longer visible, while
> fib6_nh_release_dsts can be used anywhere.
> 
> [...]

Here is the summary with links:
  - [net-next,v2] net: ipv6: use the new fib6_nh_release_dsts helper in fib6_nh_release
    https://git.kernel.org/netdev/net-next/c/613080506665

You are awesome, thank you!
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