Re: [PATCH mptcp-net v2 2/3] mptcp: use READ/WRITE_ONCE for allow_subflows

Hi Chenguang,

On 15/07/2026 08:18, Chenguang Zhao wrote:
> From: Chenguang Zhao <[email protected]>
> 
> mptcp_is_fully_established() may read allow_subflows without holding
> fallback_lock. Annotate all allow_subflows accesses with READ_ONCE and
> WRITE_ONCE to avoid data-race warnings and make the concurrency model
> explicit.

Is it not enough to use READ_ONCE only with mptcp_is_fully_established?

The others read this variable with fallback_lock. WRITE_ONCE is still
needed.

Or maybe mptcp_is_fully_established should check allow_subflows while
holding fallback_lock? (I didn't check what's best, but I don't think
this helper is used in fast paths)

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.