[tipc-discussion][net 0/2] improvement for wait and wakeup

[tipc-discussion][net 0/2] improvement for wait and wakeup

[Tung Nguyen]

Some improvements for tipc_wait_for_xzy().

Tung Nguyen (2):
  tipc: improve function tipc_wait_for_cond()
  tipc: improve function tipc_wait_for_rcvmsg()

 net/tipc/socket.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

-- 
2.17.1

[tipc-discussion][net 1/2] tipc: improve function tipc_wait_for_cond()

[Tung Nguyen]

Commit 844cf763fba6 ("tipc: make macro tipc_wait_for_cond() smp safe")
replaced finish_wait() with remove_wait_queue() but still used
prepare_to_wait(). This causes unnecessary conditional
checking  before adding to wait queue in prepare_to_wait().

This commit replaces prepare_to_wait() with add_wait_queue()
as the pair function with remove_wait_queue().

Acked-by: Ying Xue <ying.xue@windriver.com>
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: Tung Nguyen <tung.q.nguyen@dektech.com.au>
---
 net/tipc/socket.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 1217c90a363b..81b87916a0eb 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -388,7 +388,7 @@ static int tipc_sk_sock_err(struct socket *sock, long *timeout)
 		rc_ = tipc_sk_sock_err((sock_), timeo_);		       \
 		if (rc_)						       \
 			break;						       \
-		prepare_to_wait(sk_sleep(sk_), &wait_, TASK_INTERRUPTIBLE);    \
+		add_wait_queue(sk_sleep(sk_), &wait_);                         \
 		release_sock(sk_);					       \
 		*(timeo_) = wait_woken(&wait_, TASK_INTERRUPTIBLE, *(timeo_)); \
 		sched_annotate_sleep();				               \
-- 
2.17.1

[tipc-discussion][net 2/2] tipc: improve function tipc_wait_for_rcvmsg()

[Tung Nguyen]

This commit replaces schedule_timeout() with wait_woken()
in function tipc_wait_for_rcvmsg(). wait_woken() uses
memory barriers in its implementation to avoid potential
race condition when putting a process into sleeping state
and then waking it up.

Acked-by: Ying Xue <ying.xue@windriver.com>
Acked-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: Tung Nguyen <tung.q.nguyen@dektech.com.au>
---
 net/tipc/socket.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 81b87916a0eb..684f2125fc6b 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -1677,7 +1677,7 @@ static void tipc_sk_send_ack(struct tipc_sock *tsk)
 static int tipc_wait_for_rcvmsg(struct socket *sock, long *timeop)
 {
 	struct sock *sk = sock->sk;
-	DEFINE_WAIT(wait);
+	DEFINE_WAIT_FUNC(wait, woken_wake_function);
 	long timeo = *timeop;
 	int err = sock_error(sk);
 
@@ -1685,15 +1685,17 @@ static int tipc_wait_for_rcvmsg(struct socket *sock, long *timeop)
 		return err;
 
 	for (;;) {
-		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
 		if (timeo && skb_queue_empty(&sk->sk_receive_queue)) {
 			if (sk->sk_shutdown & RCV_SHUTDOWN) {
 				err = -ENOTCONN;
 				break;
 			}
+			add_wait_queue(sk_sleep(sk), &wait);
 			release_sock(sk);
-			timeo = schedule_timeout(timeo);
+			timeo = wait_woken(&wait, TASK_INTERRUPTIBLE, timeo);
+			sched_annotate_sleep();
 			lock_sock(sk);
+			remove_wait_queue(sk_sleep(sk), &wait);
 		}
 		err = 0;
 		if (!skb_queue_empty(&sk->sk_receive_queue))
@@ -1709,7 +1711,6 @@ static int tipc_wait_for_rcvmsg(struct socket *sock, long *timeop)
 		if (err)
 			break;
 	}
-	finish_wait(sk_sleep(sk), &wait);
 	*timeop = timeo;
 	return err;
 }
-- 
2.17.1

Re: [tipc-discussion][net 0/2] improvement for wait and wakeup

[David Miller]

From: Tung Nguyen <tung.q.nguyen@dektech.com.au>
Date: Tue, 19 Feb 2019 11:20:46 +0700

> Some improvements for tipc_wait_for_xzy().

Series applied.

[STABLE REQUEST] tipc: improve function tipc_wait_for_cond()

[Lee Jones]

Dear Stable,

> Commit 844cf763fba6 ("tipc: make macro tipc_wait_for_cond() smp safe")
> replaced finish_wait() with remove_wait_queue() but still used
> prepare_to_wait(). This causes unnecessary conditional
> checking  before adding to wait queue in prepare_to_wait().
>
> This commit replaces prepare_to_wait() with add_wait_queue()
> as the pair function with remove_wait_queue().
>
> Acked-by: Ying Xue <ying.xue@windriver.com>
> Acked-by: Jon Maloy <jon.maloy@ericsson.com>
> Signed-off-by: Tung Nguyen <tung.q.nguyen@dektech.com.au>
> ---
>  net/tipc/socket.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/tipc/socket.c b/net/tipc/socket.c
> index 1217c90a363b..81b87916a0eb 100644
> --- a/net/tipc/socket.c
> +++ b/net/tipc/socket.c
> @@ -388,7 +388,7 @@ static int tipc_sk_sock_err(struct socket *sock, long *timeout)
>  		rc_ = tipc_sk_sock_err((sock_), timeo_);		       \
>  		if (rc_)						       \
>  			break;						       \
> -		prepare_to_wait(sk_sleep(sk_), &wait_, TASK_INTERRUPTIBLE);    \
> +		add_wait_queue(sk_sleep(sk_), &wait_);                         \
>  		release_sock(sk_);					       \
>  		*(timeo_) = wait_woken(&wait_, TASK_INTERRUPTIBLE, *(timeo_)); \
>  		sched_annotate_sleep();				               \

Could we have this ol' classic backported to v4.19 and v4.14 please?

--
Lee Jones [李琼斯]

Re: [STABLE REQUEST] tipc: improve function tipc_wait_for_cond()

[Greg KH]

On Tue, Mar 14, 2023 at 05:45:37PM +0000, Lee Jones wrote:
> Dear Stable,
> 
> > Commit 844cf763fba6 ("tipc: make macro tipc_wait_for_cond() smp safe")
> > replaced finish_wait() with remove_wait_queue() but still used
> > prepare_to_wait(). This causes unnecessary conditional
> > checking  before adding to wait queue in prepare_to_wait().
> >
> > This commit replaces prepare_to_wait() with add_wait_queue()
> > as the pair function with remove_wait_queue().
> >
> > Acked-by: Ying Xue <ying.xue@windriver.com>
> > Acked-by: Jon Maloy <jon.maloy@ericsson.com>
> > Signed-off-by: Tung Nguyen <tung.q.nguyen@dektech.com.au>
> > ---
> >  net/tipc/socket.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/net/tipc/socket.c b/net/tipc/socket.c
> > index 1217c90a363b..81b87916a0eb 100644
> > --- a/net/tipc/socket.c
> > +++ b/net/tipc/socket.c
> > @@ -388,7 +388,7 @@ static int tipc_sk_sock_err(struct socket *sock, long *timeout)
> >  		rc_ = tipc_sk_sock_err((sock_), timeo_);		       \
> >  		if (rc_)						       \
> >  			break;						       \
> > -		prepare_to_wait(sk_sleep(sk_), &wait_, TASK_INTERRUPTIBLE);    \
> > +		add_wait_queue(sk_sleep(sk_), &wait_);                         \
> >  		release_sock(sk_);					       \
> >  		*(timeo_) = wait_woken(&wait_, TASK_INTERRUPTIBLE, *(timeo_)); \
> >  		sched_annotate_sleep();				               \
> 
> Could we have this ol' classic backported to v4.19 and v4.14 please?

What is the git commit id?

Re: [STABLE REQUEST] tipc: improve function tipc_wait_for_cond()

[Lee Jones]

On Tue, 14 Mar 2023, Greg KH wrote:

> On Tue, Mar 14, 2023 at 05:45:37PM +0000, Lee Jones wrote:
> > Dear Stable,
> >
> > > Commit 844cf763fba6 ("tipc: make macro tipc_wait_for_cond() smp safe")
> > > replaced finish_wait() with remove_wait_queue() but still used
> > > prepare_to_wait(). This causes unnecessary conditional
> > > checking  before adding to wait queue in prepare_to_wait().
> > >
> > > This commit replaces prepare_to_wait() with add_wait_queue()
> > > as the pair function with remove_wait_queue().
> > >
> > > Acked-by: Ying Xue <ying.xue@windriver.com>
> > > Acked-by: Jon Maloy <jon.maloy@ericsson.com>
> > > Signed-off-by: Tung Nguyen <tung.q.nguyen@dektech.com.au>
> > > ---
> > >  net/tipc/socket.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/net/tipc/socket.c b/net/tipc/socket.c
> > > index 1217c90a363b..81b87916a0eb 100644
> > > --- a/net/tipc/socket.c
> > > +++ b/net/tipc/socket.c
> > > @@ -388,7 +388,7 @@ static int tipc_sk_sock_err(struct socket *sock, long *timeout)
> > >  		rc_ = tipc_sk_sock_err((sock_), timeo_);		       \
> > >  		if (rc_)						       \
> > >  			break;						       \
> > > -		prepare_to_wait(sk_sleep(sk_), &wait_, TASK_INTERRUPTIBLE);    \
> > > +		add_wait_queue(sk_sleep(sk_), &wait_);                         \
> > >  		release_sock(sk_);					       \
> > >  		*(timeo_) = wait_woken(&wait_, TASK_INTERRUPTIBLE, *(timeo_)); \
> > >  		sched_annotate_sleep();				               \
> >
> > Could we have this ol' classic backported to v4.19 and v4.14 please?
>
> What is the git commit id?

Sorry, it's 223b7329ec6a0.

--
Lee Jones [李琼斯]

Re: [STABLE REQUEST] tipc: improve function tipc_wait_for_cond()

[Greg KH]

On Tue, Mar 14, 2023 at 06:04:30PM +0000, Lee Jones wrote:
> On Tue, 14 Mar 2023, Greg KH wrote:
> 
> > On Tue, Mar 14, 2023 at 05:45:37PM +0000, Lee Jones wrote:
> > > Dear Stable,
> > >
> > > > Commit 844cf763fba6 ("tipc: make macro tipc_wait_for_cond() smp safe")
> > > > replaced finish_wait() with remove_wait_queue() but still used
> > > > prepare_to_wait(). This causes unnecessary conditional
> > > > checking  before adding to wait queue in prepare_to_wait().
> > > >
> > > > This commit replaces prepare_to_wait() with add_wait_queue()
> > > > as the pair function with remove_wait_queue().
> > > >
> > > > Acked-by: Ying Xue <ying.xue@windriver.com>
> > > > Acked-by: Jon Maloy <jon.maloy@ericsson.com>
> > > > Signed-off-by: Tung Nguyen <tung.q.nguyen@dektech.com.au>
> > > > ---
> > > >  net/tipc/socket.c | 2 +-
> > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > >
> > > > diff --git a/net/tipc/socket.c b/net/tipc/socket.c
> > > > index 1217c90a363b..81b87916a0eb 100644
> > > > --- a/net/tipc/socket.c
> > > > +++ b/net/tipc/socket.c
> > > > @@ -388,7 +388,7 @@ static int tipc_sk_sock_err(struct socket *sock, long *timeout)
> > > >  		rc_ = tipc_sk_sock_err((sock_), timeo_);		       \
> > > >  		if (rc_)						       \
> > > >  			break;						       \
> > > > -		prepare_to_wait(sk_sleep(sk_), &wait_, TASK_INTERRUPTIBLE);    \
> > > > +		add_wait_queue(sk_sleep(sk_), &wait_);                         \
> > > >  		release_sock(sk_);					       \
> > > >  		*(timeo_) = wait_woken(&wait_, TASK_INTERRUPTIBLE, *(timeo_)); \
> > > >  		sched_annotate_sleep();				               \
> > >
> > > Could we have this ol' classic backported to v4.19 and v4.14 please?
> >
> > What is the git commit id?
> 
> Sorry, it's 223b7329ec6a0.

Now queued up, thanks.

greg k-h