linux-kernel - Re: [PATCH v2 1/2] locking/lockdep: Provide lockdep_assert{,

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Date:   Mon, 2 Aug 2021 11:49:19 +0200
From:   Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>
To:     Desmond Cheong Zhi Xi <desmondcheongzx@...il.com>,
        mripard@...nel.org, tzimmermann@...e.de, airlied@...ux.ie,
        daniel@...ll.ch, peterz@...radead.org, mingo@...hat.com,
        will@...nel.org, longman@...hat.com, boqun.feng@...il.com
Cc:     dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        skhan@...uxfoundation.org, gregkh@...uxfoundation.org,
        linux-kernel-mentees@...ts.linuxfoundation.org
Subject: Re: [PATCH v2 1/2] locking/lockdep: Provide lockdep_assert{,_once}()
 helpers

Op 31-07-2021 om 10:24 schreef Desmond Cheong Zhi Xi:
> From: Peter Zijlstra <peterz@...radead.org>
>
> Extract lockdep_assert{,_once}() helpers to more easily write composite
> assertions like, for example:
>
> 	lockdep_assert(lockdep_is_held(&drm_device.master_mutex) ||
> 		       lockdep_is_held(&drm_file.master_lookup_lock));
>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
> Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@...il.com>
> Acked-by: Boqun Feng <boqun.feng@...il.com>
> Acked-by: Waiman Long <longman@...hat.com>
> ---
>  include/linux/lockdep.h | 41 +++++++++++++++++++++--------------------
>  1 file changed, 21 insertions(+), 20 deletions(-)
>
> diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
> index 5cf387813754..9fe165beb0f9 100644
> --- a/include/linux/lockdep.h
> +++ b/include/linux/lockdep.h
> @@ -306,31 +306,29 @@ extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie);
>  
>  #define lockdep_depth(tsk)	(debug_locks ? (tsk)->lockdep_depth : 0)
>  
> -#define lockdep_assert_held(l)	do {					\
> -		WARN_ON(debug_locks &&					\
> -			lockdep_is_held(l) == LOCK_STATE_NOT_HELD);	\
> -	} while (0)
> +#define lockdep_assert(cond)		\
> +	do { WARN_ON(debug_locks && !(cond)); } while (0)
>  
> -#define lockdep_assert_not_held(l)	do {				\
> -		WARN_ON(debug_locks &&					\
> -			lockdep_is_held(l) == LOCK_STATE_HELD);		\
> -	} while (0)
> +#define lockdep_assert_once(cond)	\
> +	do { WARN_ON_ONCE(debug_locks && !(cond)); } while (0)
>  
> -#define lockdep_assert_held_write(l)	do {			\
> -		WARN_ON(debug_locks && !lockdep_is_held_type(l, 0));	\
> -	} while (0)
> +#define lockdep_assert_held(l)		\
> +	lockdep_assert(lockdep_is_held(l) != LOCK_STATE_NOT_HELD)
>  
> -#define lockdep_assert_held_read(l)	do {				\
> -		WARN_ON(debug_locks && !lockdep_is_held_type(l, 1));	\
> -	} while (0)
> +#define lockdep_assert_not_held(l)	\
> +	lockdep_assert(lockdep_is_held(l) != LOCK_STATE_HELD)
>  
> -#define lockdep_assert_held_once(l)	do {				\
> -		WARN_ON_ONCE(debug_locks && !lockdep_is_held(l));	\
> -	} while (0)
> +#define lockdep_assert_held_write(l)	\
> +	lockdep_assert(lockdep_is_held_type(l, 0))
>  
> -#define lockdep_assert_none_held_once()	do {				\
> -		WARN_ON_ONCE(debug_locks && current->lockdep_depth);	\
> -	} while (0)
> +#define lockdep_assert_held_read(l)	\
> +	lockdep_assert(lockdep_is_held_type(l, 1))
> +
> +#define lockdep_assert_held_once(l)		\
> +	lockdep_assert_once(lockdep_is_held(l) != LOCK_STATE_NOT_HELD)
> +
> +#define lockdep_assert_none_held_once()		\
> +	lockdep_assert_once(!current->lockdep_depth)
>  
>  #define lockdep_recursing(tsk)	((tsk)->lockdep_recursion)
>  
> @@ -407,6 +405,9 @@ extern int lock_is_held(const void *);
>  extern int lockdep_is_held(const void *);
>  #define lockdep_is_held_type(l, r)		(1)
>  
> +#define lockdep_assert(c)			do { } while (0)
> +#define lockdep_assert_once(c)			do { } while (0)
> +
>  #define lockdep_assert_held(l)			do { (void)(l); } while (0)
>  #define lockdep_assert_not_held(l)		do { (void)(l); } while (0)
>  #define lockdep_assert_held_write(l)		do { (void)(l); } while (0)

All other macros seem to do (void)(c); in this case?


Otherwise looks good.