diff mbox series

[net-next,2/6] ipv6: fib6_new_sernum() optimization

Message ID 20221115091101.2234482-3-edumazet@google.com (mailing list archive)
State Accepted
Commit 30189806fbb945c4cb753878aab0aa5af07bc921
Delegated to: Netdev Maintainers
Headers show
Series net: more try_cmpxchg() conversions | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1 this patch: 1
netdev/cc_maintainers warning 1 maintainers not CCed: yoshfuji@linux-ipv6.org
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1 this patch: 1
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 16 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Eric Dumazet Nov. 15, 2022, 9:10 a.m. UTC 
Adopt atomic_try_cmpxchg() which is slightly more efficient.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: David Ahern <dsahern@kernel.org>
---
 net/ipv6/ip6_fib.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

Comments

David Ahern Nov. 17, 2022, 12:05 a.m. UTC | #1 
On 11/15/22 2:10 AM, Eric Dumazet wrote:
> Adopt atomic_try_cmpxchg() which is slightly more efficient.
> 
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: David Ahern <dsahern@kernel.org>
> ---
>  net/ipv6/ip6_fib.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
> index 413f66781e50de62d6b20042d84798e7da59165a..2438da5ff6da810d9f612fc66df4d28510f50f10 100644
> --- a/net/ipv6/ip6_fib.c
> +++ b/net/ipv6/ip6_fib.c
> @@ -91,13 +91,12 @@ static void fib6_walker_unlink(struct net *net, struct fib6_walker *w)
>  
>  static int fib6_new_sernum(struct net *net)
>  {
> -	int new, old;
> +	int new, old = atomic_read(&net->ipv6.fib6_sernum);
>  
>  	do {
> -		old = atomic_read(&net->ipv6.fib6_sernum);
>  		new = old < INT_MAX ? old + 1 : 1;
> -	} while (atomic_cmpxchg(&net->ipv6.fib6_sernum,
> -				old, new) != old);
> +	} while (!atomic_try_cmpxchg(&net->ipv6.fib6_sernum, &old, new));
> +
>  	return new;
>  }
>  

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

Patch

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 413f66781e50de62d6b20042d84798e7da59165a..2438da5ff6da810d9f612fc66df4d28510f50f10 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -91,13 +91,12 @@  static void fib6_walker_unlink(struct net *net, struct fib6_walker *w)
 
 static int fib6_new_sernum(struct net *net)
 {
-	int new, old;
+	int new, old = atomic_read(&net->ipv6.fib6_sernum);
 
 	do {
-		old = atomic_read(&net->ipv6.fib6_sernum);
 		new = old < INT_MAX ? old + 1 : 1;
-	} while (atomic_cmpxchg(&net->ipv6.fib6_sernum,
-				old, new) != old);
+	} while (!atomic_try_cmpxchg(&net->ipv6.fib6_sernum, &old, new));
+
 	return new;
 }