Re: [PATCH] spinlock: alter inlining of _spin_lock_cb()

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Wed, 14 Jun 2023, Jan Beulich wrote:
> To comply with Misra rule 8.10 ("An inline function shall be declared
> with the static storage class"), convert what is presently
> _spin_lock_cb() to an always-inline (and static) helper, while making
> the function itself a thin wrapper, just like _spin_lock() is.
> 
> While there drop the unlikely() from the callback check, and correct
> indentation in _spin_lock().
> 
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> --- a/xen/common/spinlock.c
> +++ b/xen/common/spinlock.c
> @@ -304,7 +304,8 @@ static always_inline u16 observe_head(sp
>      return read_atomic(&t->head);
>  }
>  
> -void inline _spin_lock_cb(spinlock_t *lock, void (*cb)(void *), void *data)
> +static void always_inline spin_lock_common(spinlock_t *lock,
> +                                           void (*cb)(void *), void *data)
>  {
>      spinlock_tickets_t tickets = SPINLOCK_TICKET_INC;
>      LOCK_PROFILE_VAR;
> @@ -316,7 +317,7 @@ void inline _spin_lock_cb(spinlock_t *lo
>      while ( tickets.tail != observe_head(&lock->tickets) )
>      {
>          LOCK_PROFILE_BLOCK;
> -        if ( unlikely(cb) )
> +        if ( cb )
>              cb(data);
>          arch_lock_relax();
>      }
> @@ -327,7 +328,12 @@ void inline _spin_lock_cb(spinlock_t *lo
>  
>  void _spin_lock(spinlock_t *lock)
>  {
> -     _spin_lock_cb(lock, NULL, NULL);
> +    spin_lock_common(lock, NULL, NULL);
> +}
> +
> +void _spin_lock_cb(spinlock_t *lock, void (*cb)(void *), void *data)
> +{
> +    spin_lock_common(lock, cb, data);
>  }
>  
>  void _spin_lock_irq(spinlock_t *lock)
>