[PATCH v2 2/5] seqlock: Use unique prefix for seqcount_t property accessors

From: Ahmed S. Darwish
Date: Fri Sep 04 2020 - 11:32:32 EST


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: 55f3560df975 ("seqlock: Extend seqcount API with associated locks")
Signed-off-by: Ahmed S. Darwish <a.darwish@xxxxxxxxxxxxx>
---
include/linux/seqlock.h | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h
index 4f219df659b1..96198da7debc 100644
--- a/include/linux/seqlock.h
+++ b/include/linux/seqlock.h
@@ -157,7 +157,9 @@ static inline void seqcount_lockdep_reader_access(const seqcount_t *s)
*/

/*
- * SEQCOUNT_LOCKNAME() - Instantiate seqcount_LOCKNAME_t and helpers
+ * SEQCOUNT_LOCKNAME() - Instantiate seqcount_LOCKNAME_t and helpers
+ * seqprop_seqcount_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_seqcount_##lockname##_ptr(seqcount_##lockname##_t *s) \
{ \
return &s->seqcount; \
} \
\
static __always_inline bool \
-__seqcount_##lockname##_preemptible(seqcount_##lockname##_t *s) \
+__seqprop_seqcount_##lockname##_preemptible(const seqcount_##lockname##_t *s)\
{ \
return preemptible; \
} \
\
static __always_inline void \
-__seqcount_##lockname##_assert(seqcount_##lockname##_t *s) \
+__seqprop_seqcount_##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_seqcount_ptr(seqcount_t *s)
{
return s;
}

-static inline bool __seqcount_preemptible(seqcount_t *s)
+static inline bool __seqprop_seqcount_preemptible(const seqcount_t *s)
{
return false;
}

-static inline void __seqcount_assert(seqcount_t *s)
+static inline void __seqprop_seqcount_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_seqcount_##lockname##_##prop((void *)(s))

#define __seqprop(s, prop) _Generic(*(s), \
- seqcount_t: __seqcount_##prop((void *)(s)), \
+ seqcount_t: __seqprop_seqcount_##prop((void *)(s)), \
__seqprop_case((s), raw_spinlock, prop), \
__seqprop_case((s), spinlock, prop), \
__seqprop_case((s), rwlock, prop), \
--
2.28.0