Commit 5cdd2557 authored by Ahmed S. Darwish's avatar Ahmed S. Darwish Committed by Peter Zijlstra
Browse files

seqlock: Use unique prefix for seqcount_t property accessors 



At seqlock.h, the following set of functions:

    - __seqcount_ptr()
    - __seqcount_preemptible()
    - __seqcount_assert()

act as plain seqcount_t "property" accessors. Meanwhile, the following
group:

    - __seqcount_ptr()
    - __seqcount_lock_preemptible()
    - __seqcount_assert_lock_held()

act as the equivalent set, but in the generic form, taking either
seqcount_t or any of the seqcount_LOCKNAME_t variants.

This is quite confusing, especially the first member where it is called
exactly the same in both groups.

Differentiate the first group by using "__seqprop" as prefix, and also
use that same prefix for all of seqcount_LOCKNAME_t property accessors.

While at it, constify the property accessors first parameter when
appropriate.

References: 55f3560d ("seqlock: Extend seqcount API with associated locks")
Signed-off-by: default avatarAhmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200904153231.11994-3-a.darwish@linutronix.de
parent 6dd699b1

include/linux/seqlock.h

+11 −9
Original line number Diff line number Diff line
@@ -158,6 +158,8 @@ static inline void seqcount_lockdep_reader_access(const seqcount_t *s) 


/*

 * SEQCOUNT_LOCKNAME()	- Instantiate seqcount_LOCKNAME_t and helpers

 * seqprop_LOCKNAME_*()	- Property accessors for seqcount_LOCKNAME_t

 *

 * @lockname:		"LOCKNAME" part of seqcount_LOCKNAME_t

 * @locktype:		LOCKNAME canonical C data type

 * @preemptible:	preemptibility of above lockname
@@ -177,19 +179,19 @@ seqcount_##lockname##_init(seqcount_##lockname##_t *s, locktype *lock) \ 
}									\

									\

static __always_inline seqcount_t *					\

__seqcount_##lockname##_ptr(seqcount_##lockname##_t *s)			\

__seqprop_##lockname##_ptr(seqcount_##lockname##_t *s)			\

{									\

	return &s->seqcount;						\

}									\

									\

static __always_inline bool						\

__seqcount_##lockname##_preemptible(seqcount_##lockname##_t *s)		\

__seqprop_##lockname##_preemptible(const seqcount_##lockname##_t *s)	\

{									\

	return preemptible;						\

}									\

									\

static __always_inline void						\

__seqcount_##lockname##_assert(seqcount_##lockname##_t *s)		\

__seqprop_##lockname##_assert(const seqcount_##lockname##_t *s)		\

{									\

	__SEQ_LOCK(lockdep_assert_held(lockmember));			\

}
@@ -198,17 +200,17 @@ __seqcount_##lockname##_assert(seqcount_##lockname##_t *s) \ 
 * __seqprop() for seqcount_t

 */



static inline seqcount_t *__seqcount_ptr(seqcount_t *s)

static inline seqcount_t *__seqprop_ptr(seqcount_t *s)

{

	return s;

}



static inline bool __seqcount_preemptible(seqcount_t *s)

static inline bool __seqprop_preemptible(const seqcount_t *s)

{

	return false;

}



static inline void __seqcount_assert(seqcount_t *s)

static inline void __seqprop_assert(const seqcount_t *s)

{

	lockdep_assert_preemption_disabled();

}
@@ -237,10 +239,10 @@ SEQCOUNT_LOCKNAME(ww_mutex, struct ww_mutex, true, &s->lock->base) 
#define SEQCNT_WW_MUTEX_ZERO(name, lock) 	SEQCOUNT_LOCKNAME_ZERO(name, lock)



#define __seqprop_case(s, lockname, prop)				\

	seqcount_##lockname##_t: __seqcount_##lockname##_##prop((void *)(s))

	seqcount_##lockname##_t: __seqprop_##lockname##_##prop((void *)(s))



#define __seqprop(s, prop) _Generic(*(s),				\

	seqcount_t:		__seqcount_##prop((void *)(s)),		\

	seqcount_t:		__seqprop_##prop((void *)(s)),		\

	__seqprop_case((s),	raw_spinlock,	prop),			\

	__seqprop_case((s),	spinlock,	prop),			\

	__seqprop_case((s),	rwlock,		prop),			\

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