Re: [PATCH bpf-next 1/2] srcu: Add lock guard for srcu_fast_updown flavor

[Oleg Nesterov]

On 07/06, Puranjay Mohan wrote:
>
> Add a guard(srcu_fast_updown) definition for scoped
> SRCU-fast-updown read-side critical sections, following the
> existing pattern of guard(srcu) and guard(srcu_fast).
>
> Signed-off-by: Puranjay Mohan <puranjay@xxxxxxxxxx>
> ---
>  include/linux/srcu.h | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/include/linux/srcu.h b/include/linux/srcu.h
> index a54ce9e808b92..72c86d3b23f2e 100644
> --- a/include/linux/srcu.h
> +++ b/include/linux/srcu.h
> @@ -638,4 +638,11 @@ DEFINE_LOCK_GUARD_1(srcu_fast_notrace, struct srcu_struct,
>  DECLARE_LOCK_GUARD_1_ATTRS(srcu_fast_notrace, __acquires_shared(_T), __releases_shared(*(struct srcu_struct **)_T))
>  #define class_srcu_fast_notrace_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(srcu_fast_notrace, _T)
>
> +DEFINE_LOCK_GUARD_1(srcu_fast_updown, struct srcu_struct,
> +		    _T->scp = srcu_read_lock_fast_updown(_T->lock),
> +		    srcu_read_unlock_fast_updown(_T->lock, _T->scp),
> +		    struct srcu_ctr __percpu *scp)
> +DECLARE_LOCK_GUARD_1_ATTRS(srcu_fast_updown, __acquires_shared(_T), __releases_shared(*(struct srcu_struct **)_T))
> +#define class_srcu_fast_updown_constructor(_T) WITH_LOCK_GUARD_1_ATTRS(srcu_fast_updown, _T)

Looks "obviously correct" to me. FWIW,

Reviewed-by: Oleg Nesterov <oleg@xxxxxxxxxx>