Re: [MPTCP][PATCH mptcp-next] Squash to "mptcp: fix ADD_ADDR and RM_ADDR maybe flush addr_signal each other"

[Geliang Tang <geliangtang@gmail.com>]

Yonglong Li <liyonglong@chinatelecom.cn> 于2021年7月12日周一 下午5:55写道：
>
>
>
> On 2021/7/11 23:15, Geliang Tang wrote:
> > Add READ_ONCE() for reading msk->pm.addr_signal.
> >
> > Use mptcp_pm_should_add_signal_echo instead of open coding.
> >
> > Use '&=' to clear flag.
> >
> > Signed-off-by: Geliang Tang <geliangtang@gmail.com>
> > ---
> >  net/mptcp/pm.c | 12 ++++++++----
> >  1 file changed, 8 insertions(+), 4 deletions(-)
> >
> > diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
> > index c9622696716e..be16da2dcb6b 100644
> > --- a/net/mptcp/pm.c
> > +++ b/net/mptcp/pm.c
> > @@ -257,6 +257,7 @@ bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
> >                             struct mptcp_addr_info *saddr, bool *echo, bool *port)
> >  {
> >       int ret = false;
> > +     u8 add_addr;
> >
> >       spin_lock_bh(&msk->pm.lock);
> >
> > @@ -271,10 +272,12 @@ bool mptcp_pm_add_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
> >               goto out_unlock;
> >
> >       *saddr = msk->pm.local;
> > -     if ((msk->pm.addr_signal & BIT(MPTCP_ADD_ADDR_ECHO)))
> > -             WRITE_ONCE(msk->pm.addr_signal, msk->pm.addr_signal & ~BIT(MPTCP_ADD_ADDR_ECHO));
> > +     add_addr = READ_ONCE(msk->pm.addr_signal);
> > +     if (mptcp_pm_should_add_signal_echo(msk))
> > +             add_addr &= ~BIT(MPTCP_ADD_ADDR_ECHO);
> >       else
> > -             WRITE_ONCE(msk->pm.addr_signal, msk->pm.addr_signal & ~BIT(MPTCP_ADD_ADDR_SIGNAL));
> > +             add_addr &= ~BIT(MPTCP_ADD_ADDR_SIGNAL);
> > +     WRITE_ONCE(msk->pm.addr_signal, add_addr);
> >       ret = true;
> >
> >  out_unlock:
> > @@ -294,7 +297,8 @@ bool mptcp_pm_rm_addr_signal(struct mptcp_sock *msk, unsigned int remaining,
> >       if (!mptcp_pm_should_rm_signal(msk))
> >               goto out_unlock;
> >
> > -     rm_addr = msk->pm.addr_signal & ~BIT(MPTCP_RM_ADDR_SIGNAL);
> > +     rm_addr = READ_ONCE(msk->pm.addr_signal);
> > +     rm_addr &= ~BIT(MPTCP_RM_ADDR_SIGNAL);
> >       len = mptcp_rm_addr_len(&msk->pm.rm_list_tx);
> >       if (len < 0) {
> >               WRITE_ONCE(msk->pm.addr_signal, rm_addr);
> >
>
> These chunk of code is under the pm.lock so It is no need to use READ_ONCE() as Paolo saied before.

I'll drop this READ_ONCE() in v2.

>
> --
> Li YongLong