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

[Yonglong Li <liyonglong@chinatelecom.cn>]

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.

-- 
Li YongLong