diff mbox series

[net-next,3/4] tcp: simplify tcp_set_congestion_control(): always reinitialize

Message ID 20200909181556.2945496-4-ncardwell@google.com
State Changes Requested
Delegated to: BPF Maintainers
Headers show
Series tcp: increase flexibility of EBPF congestion control initialization | expand

Commit Message

Neal Cardwell Sept. 9, 2020, 6:15 p.m. UTC 
Now that the previous patches ensure that all call sites for
tcp_set_congestion_control() want to initialize congestion control, we
can simplify tcp_set_congestion_control() by removing the reinit
argument and the code to support it.

Signed-off-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Kevin Yang <yyd@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Lawrence Brakmo <brakmo@fb.com>
---
 include/net/tcp.h   |  2 +-
 net/core/filter.c   |  3 +--
 net/ipv4/tcp.c      |  2 +-
 net/ipv4/tcp_cong.c | 11 ++---------
 4 files changed, 5 insertions(+), 13 deletions(-)

Comments

Martin KaFai Lau Sept. 10, 2020, 12:29 a.m. UTC | #1 
On Wed, Sep 09, 2020 at 02:15:55PM -0400, Neal Cardwell wrote:
> Now that the previous patches ensure that all call sites for
> tcp_set_congestion_control() want to initialize congestion control, we
> can simplify tcp_set_congestion_control() by removing the reinit
> argument and the code to support it.
> 
> Signed-off-by: Neal Cardwell <ncardwell@google.com>
> Acked-by: Yuchung Cheng <ycheng@google.com>
> Acked-by: Kevin Yang <yyd@google.com>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: Lawrence Brakmo <brakmo@fb.com>
> ---
>  include/net/tcp.h   |  2 +-
>  net/core/filter.c   |  3 +--
>  net/ipv4/tcp.c      |  2 +-
>  net/ipv4/tcp_cong.c | 11 ++---------
>  4 files changed, 5 insertions(+), 13 deletions(-)
> 
> diff --git a/include/net/tcp.h b/include/net/tcp.h
> index e85d564446c6..f857146c17a5 100644
> --- a/include/net/tcp.h
> +++ b/include/net/tcp.h
> @@ -1104,7 +1104,7 @@ void tcp_get_available_congestion_control(char *buf, size_t len);
>  void tcp_get_allowed_congestion_control(char *buf, size_t len);
>  int tcp_set_allowed_congestion_control(char *allowed);
>  int tcp_set_congestion_control(struct sock *sk, const char *name, bool load,
> -			       bool reinit, bool cap_net_admin);
> +			       bool cap_net_admin);
>  u32 tcp_slow_start(struct tcp_sock *tp, u32 acked);
>  void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w, u32 acked);
>  
> diff --git a/net/core/filter.c b/net/core/filter.c
> index b26c04924fa3..0bd0a97ee951 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -4451,8 +4451,7 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname,
>  			strncpy(name, optval, min_t(long, optlen,
>  						    TCP_CA_NAME_MAX-1));
>  			name[TCP_CA_NAME_MAX-1] = 0;
> -			ret = tcp_set_congestion_control(sk, name, false,
> -							 true, true);
> +			ret = tcp_set_congestion_control(sk, name, false, true);
>  		} else {
>  			struct inet_connection_sock *icsk = inet_csk(sk);
>  			struct tcp_sock *tp = tcp_sk(sk);
> diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
> index 7360d3db2b61..e58ab9db73ff 100644
> --- a/net/ipv4/tcp.c
> +++ b/net/ipv4/tcp.c
> @@ -3050,7 +3050,7 @@ static int do_tcp_setsockopt(struct sock *sk, int level, int optname,
>  		name[val] = 0;
>  
>  		lock_sock(sk);
> -		err = tcp_set_congestion_control(sk, name, true, true,
> +		err = tcp_set_congestion_control(sk, name, true,
>  						 ns_capable(sock_net(sk)->user_ns,
>  							    CAP_NET_ADMIN));
>  		release_sock(sk);
> diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
> index d18d7a1ce4ce..a9b0fb52a1ec 100644
> --- a/net/ipv4/tcp_cong.c
> +++ b/net/ipv4/tcp_cong.c
> @@ -341,7 +341,7 @@ int tcp_set_allowed_congestion_control(char *val)
>   * already initialized.
>   */
>  int tcp_set_congestion_control(struct sock *sk, const char *name, bool load,
> -			       bool reinit, bool cap_net_admin)
> +			       bool cap_net_admin)
>  {
>  	struct inet_connection_sock *icsk = inet_csk(sk);
>  	const struct tcp_congestion_ops *ca;
> @@ -365,15 +365,8 @@ int tcp_set_congestion_control(struct sock *sk, const char *name, bool load,
>  	if (!ca) {
>  		err = -ENOENT;
>  	} else if (!load) {
nit.

I think this "else if (!load)" case can be completely removed and simply
allow it to fall through to the last
"else { tcp_reinit_congestion_control(sk, ca); }" .

> -		const struct tcp_congestion_ops *old_ca = icsk->icsk_ca_ops;
> -
>  		if (bpf_try_module_get(ca, ca->owner)) {
> -			if (reinit) {
> -				tcp_reinit_congestion_control(sk, ca);
> -			} else {
> -				icsk->icsk_ca_ops = ca;
> -				bpf_module_put(old_ca, old_ca->owner);
> -			}
> +			tcp_reinit_congestion_control(sk, ca);
>  		} else {
>  			err = -EBUSY;
>  		}
> -- 
> 2.28.0.526.ge36021eeef-goog
>
Neal Cardwell Sept. 10, 2020, 3:17 a.m. UTC | #2 
On Wed, Sep 9, 2020 at 8:29 PM Martin KaFai Lau <kafai@fb.com> wrote:
>
> On Wed, Sep 09, 2020 at 02:15:55PM -0400, Neal Cardwell wrote:
> > Now that the previous patches ensure that all call sites for
> > tcp_set_congestion_control() want to initialize congestion control, we
> > can simplify tcp_set_congestion_control() by removing the reinit
> > argument and the code to support it.
> >
> > Signed-off-by: Neal Cardwell <ncardwell@google.com>
> > Acked-by: Yuchung Cheng <ycheng@google.com>
> > Acked-by: Kevin Yang <yyd@google.com>
> > Signed-off-by: Eric Dumazet <edumazet@google.com>
> > Cc: Lawrence Brakmo <brakmo@fb.com>
> > ---
> >  include/net/tcp.h   |  2 +-
> >  net/core/filter.c   |  3 +--
> >  net/ipv4/tcp.c      |  2 +-
> >  net/ipv4/tcp_cong.c | 11 ++---------
> >  4 files changed, 5 insertions(+), 13 deletions(-)
> >
> > diff --git a/include/net/tcp.h b/include/net/tcp.h
> > index e85d564446c6..f857146c17a5 100644
> > --- a/include/net/tcp.h
> > +++ b/include/net/tcp.h
> > @@ -1104,7 +1104,7 @@ void tcp_get_available_congestion_control(char *buf, size_t len);
> >  void tcp_get_allowed_congestion_control(char *buf, size_t len);
> >  int tcp_set_allowed_congestion_control(char *allowed);
> >  int tcp_set_congestion_control(struct sock *sk, const char *name, bool load,
> > -                            bool reinit, bool cap_net_admin);
> > +                            bool cap_net_admin);
> >  u32 tcp_slow_start(struct tcp_sock *tp, u32 acked);
> >  void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w, u32 acked);
> >
> > diff --git a/net/core/filter.c b/net/core/filter.c
> > index b26c04924fa3..0bd0a97ee951 100644
> > --- a/net/core/filter.c
> > +++ b/net/core/filter.c
> > @@ -4451,8 +4451,7 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname,
> >                       strncpy(name, optval, min_t(long, optlen,
> >                                                   TCP_CA_NAME_MAX-1));
> >                       name[TCP_CA_NAME_MAX-1] = 0;
> > -                     ret = tcp_set_congestion_control(sk, name, false,
> > -                                                      true, true);
> > +                     ret = tcp_set_congestion_control(sk, name, false, true);
> >               } else {
> >                       struct inet_connection_sock *icsk = inet_csk(sk);
> >                       struct tcp_sock *tp = tcp_sk(sk);
> > diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
> > index 7360d3db2b61..e58ab9db73ff 100644
> > --- a/net/ipv4/tcp.c
> > +++ b/net/ipv4/tcp.c
> > @@ -3050,7 +3050,7 @@ static int do_tcp_setsockopt(struct sock *sk, int level, int optname,
> >               name[val] = 0;
> >
> >               lock_sock(sk);
> > -             err = tcp_set_congestion_control(sk, name, true, true,
> > +             err = tcp_set_congestion_control(sk, name, true,
> >                                                ns_capable(sock_net(sk)->user_ns,
> >                                                           CAP_NET_ADMIN));
> >               release_sock(sk);
> > diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
> > index d18d7a1ce4ce..a9b0fb52a1ec 100644
> > --- a/net/ipv4/tcp_cong.c
> > +++ b/net/ipv4/tcp_cong.c
> > @@ -341,7 +341,7 @@ int tcp_set_allowed_congestion_control(char *val)
> >   * already initialized.
> >   */
> >  int tcp_set_congestion_control(struct sock *sk, const char *name, bool load,
> > -                            bool reinit, bool cap_net_admin)
> > +                            bool cap_net_admin)
> >  {
> >       struct inet_connection_sock *icsk = inet_csk(sk);
> >       const struct tcp_congestion_ops *ca;
> > @@ -365,15 +365,8 @@ int tcp_set_congestion_control(struct sock *sk, const char *name, bool load,
> >       if (!ca) {
> >               err = -ENOENT;
> >       } else if (!load) {
> nit.
>
> I think this "else if (!load)" case can be completely removed and simply
> allow it to fall through to the last
> "else { tcp_reinit_congestion_control(sk, ca); }" .

Thanks, Martin. That is a very nice observation, and I think you are
right that we can make the additional refactor/simplification/clean-up
that you mention, without changing behavior. For clarity I think that
would be nice to have as a separate follow-on commit. Are you
interested in posting a follow-on patch for that, since it's your nice
idea?

thanks,
neal
diff mbox series

Patch

diff --git a/include/net/tcp.h b/include/net/tcp.h
index e85d564446c6..f857146c17a5 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1104,7 +1104,7 @@  void tcp_get_available_congestion_control(char *buf, size_t len);
 void tcp_get_allowed_congestion_control(char *buf, size_t len);
 int tcp_set_allowed_congestion_control(char *allowed);
 int tcp_set_congestion_control(struct sock *sk, const char *name, bool load,
-			       bool reinit, bool cap_net_admin);
+			       bool cap_net_admin);
 u32 tcp_slow_start(struct tcp_sock *tp, u32 acked);
 void tcp_cong_avoid_ai(struct tcp_sock *tp, u32 w, u32 acked);
 
diff --git a/net/core/filter.c b/net/core/filter.c
index b26c04924fa3..0bd0a97ee951 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4451,8 +4451,7 @@  static int _bpf_setsockopt(struct sock *sk, int level, int optname,
 			strncpy(name, optval, min_t(long, optlen,
 						    TCP_CA_NAME_MAX-1));
 			name[TCP_CA_NAME_MAX-1] = 0;
-			ret = tcp_set_congestion_control(sk, name, false,
-							 true, true);
+			ret = tcp_set_congestion_control(sk, name, false, true);
 		} else {
 			struct inet_connection_sock *icsk = inet_csk(sk);
 			struct tcp_sock *tp = tcp_sk(sk);
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 7360d3db2b61..e58ab9db73ff 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3050,7 +3050,7 @@  static int do_tcp_setsockopt(struct sock *sk, int level, int optname,
 		name[val] = 0;
 
 		lock_sock(sk);
-		err = tcp_set_congestion_control(sk, name, true, true,
+		err = tcp_set_congestion_control(sk, name, true,
 						 ns_capable(sock_net(sk)->user_ns,
 							    CAP_NET_ADMIN));
 		release_sock(sk);
diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index d18d7a1ce4ce..a9b0fb52a1ec 100644
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -341,7 +341,7 @@  int tcp_set_allowed_congestion_control(char *val)
  * already initialized.
  */
 int tcp_set_congestion_control(struct sock *sk, const char *name, bool load,
-			       bool reinit, bool cap_net_admin)
+			       bool cap_net_admin)
 {
 	struct inet_connection_sock *icsk = inet_csk(sk);
 	const struct tcp_congestion_ops *ca;
@@ -365,15 +365,8 @@  int tcp_set_congestion_control(struct sock *sk, const char *name, bool load,
 	if (!ca) {
 		err = -ENOENT;
 	} else if (!load) {
-		const struct tcp_congestion_ops *old_ca = icsk->icsk_ca_ops;
-
 		if (bpf_try_module_get(ca, ca->owner)) {
-			if (reinit) {
-				tcp_reinit_congestion_control(sk, ca);
-			} else {
-				icsk->icsk_ca_ops = ca;
-				bpf_module_put(old_ca, old_ca->owner);
-			}
+			tcp_reinit_congestion_control(sk, ca);
 		} else {
 			err = -EBUSY;
 		}