Re: [PATCH 1/1] rcu/sync: remove un-used rcu_sync_enter_start function

[Paul E. McKenney]

On Thu, Jan 11, 2024 at 02:57:22PM +0530, Onkarnarth wrote:
> From: Onkarnath <onkarnath.1@xxxxxxxxxxx>
> 
> With commit '6a010a49b63a ("cgroup: Make !percpu threadgroup_rwsem
> operations optional")' usage of rcu_sync_enter_start is removed.
> 
> So this function can also be removed.
> 
> Signed-off-by: Onkarnath <onkarnath.1@xxxxxxxxxxx>
> Signed-off-by: Maninder Singh <maninder1.s@xxxxxxxxxxx>

Adding Oleg, Peter, and Tejun for their thoughts.  Any objections?

							Thanx, Paul

> ---
>  include/linux/rcu_sync.h |  1 -
>  kernel/rcu/sync.c        | 16 ----------------
>  2 files changed, 17 deletions(-)
> 
> diff --git a/include/linux/rcu_sync.h b/include/linux/rcu_sync.h
> index 0027d4c8087c..3860dbb9107a 100644
> --- a/include/linux/rcu_sync.h
> +++ b/include/linux/rcu_sync.h
> @@ -37,7 +37,6 @@ static inline bool rcu_sync_is_idle(struct rcu_sync *rsp)
>  }
>  
>  extern void rcu_sync_init(struct rcu_sync *);
> -extern void rcu_sync_enter_start(struct rcu_sync *);
>  extern void rcu_sync_enter(struct rcu_sync *);
>  extern void rcu_sync_exit(struct rcu_sync *);
>  extern void rcu_sync_dtor(struct rcu_sync *);
> diff --git a/kernel/rcu/sync.c b/kernel/rcu/sync.c
> index e550f97779b8..86df878a2fee 100644
> --- a/kernel/rcu/sync.c
> +++ b/kernel/rcu/sync.c
> @@ -24,22 +24,6 @@ void rcu_sync_init(struct rcu_sync *rsp)
>  	init_waitqueue_head(&rsp->gp_wait);
>  }
>  
> -/**
> - * rcu_sync_enter_start - Force readers onto slow path for multiple updates
> - * @rsp: Pointer to rcu_sync structure to use for synchronization
> - *
> - * Must be called after rcu_sync_init() and before first use.
> - *
> - * Ensures rcu_sync_is_idle() returns false and rcu_sync_{enter,exit}()
> - * pairs turn into NO-OPs.
> - */
> -void rcu_sync_enter_start(struct rcu_sync *rsp)
> -{
> -	rsp->gp_count++;
> -	rsp->gp_state = GP_PASSED;
> -}
> -
> -
>  static void rcu_sync_func(struct rcu_head *rhp);
>  
>  static void rcu_sync_call(struct rcu_sync *rsp)
> -- 
> 2.25.1
>