linux-kernel - Re: [PATCH 1/3] cleanup: provide DEFINE_LOCK_GUARD

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Date: Wed, 10 Jan 2024 14:00:41 -0800
From: Boqun Feng <boqun.feng@...il.com>
To: Bartosz Golaszewski <brgl@...ev.pl>
Cc: Linus Walleij <linus.walleij@...aro.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>, Will Deacon <will@...nel.org>,
	Waiman Long <longman@...hat.com>, linux-gpio@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: Re: [PATCH 1/3] cleanup: provide DEFINE_LOCK_GUARD_ARGS()

On Wed, Jan 10, 2024 at 09:32:13PM +0100, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> 
> This macro allows defining lock guard with additional arguments that
> can be passed to the locking function. This is useful for implementing
> guards for nested locking.
> 
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> ---
>  include/linux/cleanup.h | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/include/linux/cleanup.h b/include/linux/cleanup.h
> index c2d09bc4f976..921db45023bb 100644
> --- a/include/linux/cleanup.h
> +++ b/include/linux/cleanup.h
> @@ -246,5 +246,11 @@ __DEFINE_LOCK_GUARD_0(_name, _lock)
>  	static inline void * class_##_name##_ext##_lock_ptr(class_##_name##_t *_T) \
>  	{ return class_##_name##_lock_ptr(_T); }
>  
> +/*
> + * Helper for implementing guard locks with additional arguments passed to
> + * the locking function.
> + */
> +#define DEFINE_LOCK_GUARD_ARGS(_name, _type, _lock, _unlock, _args...)	\
> +DEFINE_CLASS(_name, _type, _unlock, ({ _lock; _T; }), _type _T, _args)
>  

First I think the name should really be DEFINE_GUARD_ARGS(), these
DEFINE_LOCK_GUARD_*() functions have different meaning. Also this should
really be a more generic case than DEFINE_GUARD(), so how about the
following:

diff --git a/include/linux/cleanup.h b/include/linux/cleanup.h
index c2d09bc4f976..4fcdcb478fd1 100644
--- a/include/linux/cleanup.h
+++ b/include/linux/cleanup.h
@@ -148,11 +148,14 @@ static inline class_##_name##_t class_##_name##ext##_constructor(_init_args) \
  *
  */
 
-#define DEFINE_GUARD(_name, _type, _lock, _unlock) \
-	DEFINE_CLASS(_name, _type, if (_T) { _unlock; }, ({ _lock; _T; }), _type _T); \
+#define DEFINE_GUARD_ARGS(_name, _type, _lock, _unlock, _args...) \
+	DEFINE_CLASS(_name, _type, if (_T) { _unlock; }, ({ _lock; _T; }), _type _T, ##_args) \
 	static inline void * class_##_name##_lock_ptr(class_##_name##_t *_T) \
 	{ return *_T; }
 
+#define DEFINE_GUARD(_name, _type, _lock, _unlock) \
+	DEFINE_GUARD_ARGS(_name, _type, _lock, _unlock)
+
 #define DEFINE_GUARD_COND(_name, _ext, _condlock) \
 	EXTEND_CLASS(_name, _ext, \
 		     ({ void *_t = _T; if (_T && !(_condlock)) _t = NULL; _t; }), \

Thoughts?

Regards,
Boqun


>  #endif /* __LINUX_GUARDS_H */
> -- 
> 2.40.1
>