Messages in this thread Patch in this message | | | From | Alexander Aring <> | Subject | [RFC 1/2] refcount: introduce generic lockptr funcs | Date | Fri, 3 Nov 2023 12:16:34 -0400 |
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This patch introduce lockptr refcount operations. Currently refcount has a lot of refcount_dec_and_lock() functionality for most common used locktype. Those functions look mostly all the same and is duplicated inside the refcount implementation. Instead of introducing a new whole refcount_dec_and_lock() functionality e.g. for rwlock_t and their _bh variants this patch will introduce lockptr. A lockptr is just a void * and refers to the actual locking instance that can even be an own locking type. Over the passed callbacks for lock and unlock operations the void *lockptr becomes to the real thing by casting it and do the locktype specific lock operation.
Signed-off-by: Alexander Aring <aahringo@redhat.com> --- include/linux/refcount.h | 15 +++++++ lib/refcount.c | 92 ++++++++++++++++++++++++++++------------ 2 files changed, 80 insertions(+), 27 deletions(-)
diff --git a/include/linux/refcount.h b/include/linux/refcount.h index a62fcca97486..7b1fb85212cc 100644 --- a/include/linux/refcount.h +++ b/include/linux/refcount.h @@ -366,4 +366,19 @@ extern __must_check bool refcount_dec_and_lock(refcount_t *r, spinlock_t *lock) extern __must_check bool refcount_dec_and_lock_irqsave(refcount_t *r, spinlock_t *lock, unsigned long *flags) __cond_acquires(lock); +extern bool refcount_dec_and_lockptr(refcount_t *r, void (*lock)(void *lockptr), + void (*unlock)(void *lockptr), void *lockptr) __cond_acquires(lockptr); + +extern void lockptr_mutex_lock(void *lockptr) __acquires(lockptr); +extern void lockptr_mutex_unlock(void *lockptr) __releases(lockptr); +extern void lockptr_spin_lock(void *lockptr) __acquires(lockptr); +extern void lockptr_spin_unlock(void *lockptr) __releases(lockptr); + +struct lockptr_irqsave_data { + void *lockptr; + unsigned long *flags; +}; +extern void lockptr_irqsave(void *lockptr) __acquires(lockptr); +extern void lockptr_irqsave(void *lockptr) __releases(lockptr); + #endif /* _LINUX_REFCOUNT_H */ diff --git a/lib/refcount.c b/lib/refcount.c index a207a8f22b3c..e28678f0f473 100644 --- a/lib/refcount.c +++ b/lib/refcount.c @@ -94,6 +94,34 @@ bool refcount_dec_not_one(refcount_t *r) } EXPORT_SYMBOL(refcount_dec_not_one); +bool refcount_dec_and_lockptr(refcount_t *r, void (*lock)(void *lockptr), + void (*unlock)(void *lockptr), void *lockptr) +{ + if (refcount_dec_not_one(r)) + return false; + + lock(lockptr); + if (!refcount_dec_and_test(r)) { + unlock(lockptr); + return false; + } + + return true; +} +EXPORT_SYMBOL(refcount_dec_and_lockptr); + +void lockptr_mutex_lock(void *lockptr) +{ + mutex_lock(lockptr); +} +EXPORT_SYMBOL(lockptr_mutex_lock); + +void lockptr_mutex_unlock(void *lockptr) +{ + mutex_unlock(lockptr); +} +EXPORT_SYMBOL(lockptr_mutex_unlock); + /** * refcount_dec_and_mutex_lock - return holding mutex if able to decrement * refcount to 0 @@ -112,18 +140,22 @@ EXPORT_SYMBOL(refcount_dec_not_one); */ bool refcount_dec_and_mutex_lock(refcount_t *r, struct mutex *lock) { - if (refcount_dec_not_one(r)) - return false; + return refcount_dec_and_lockptr(r, lockptr_mutex_lock, + lockptr_mutex_unlock, lock); +} +EXPORT_SYMBOL(refcount_dec_and_mutex_lock); - mutex_lock(lock); - if (!refcount_dec_and_test(r)) { - mutex_unlock(lock); - return false; - } +void lockptr_spin_lock(void *lockptr) +{ + spin_lock(lockptr); +} +EXPORT_SYMBOL(lockptr_spin_lock); - return true; +void lockptr_spin_unlock(void *lockptr) +{ + spin_unlock(lockptr); } -EXPORT_SYMBOL(refcount_dec_and_mutex_lock); +EXPORT_SYMBOL(lockptr_spin_unlock); /** * refcount_dec_and_lock - return holding spinlock if able to decrement @@ -143,18 +175,26 @@ EXPORT_SYMBOL(refcount_dec_and_mutex_lock); */ bool refcount_dec_and_lock(refcount_t *r, spinlock_t *lock) { - if (refcount_dec_not_one(r)) - return false; + return refcount_dec_and_lockptr(r, lockptr_spin_lock, + lockptr_spin_unlock, lock); +} +EXPORT_SYMBOL(refcount_dec_and_lock); - spin_lock(lock); - if (!refcount_dec_and_test(r)) { - spin_unlock(lock); - return false; - } +void lockptr_lock_irqsave(void *lockptr) +{ + struct lockptr_irqsave_data *d = lockptr; - return true; + spin_lock_irqsave(d->lockptr, *d->flags); } -EXPORT_SYMBOL(refcount_dec_and_lock); +EXPORT_SYMBOL(lockptr_lock_irqsave); + +void lockptr_unlock_irqsave(void *lockptr) +{ + struct lockptr_irqsave_data *d = lockptr; + + spin_unlock_irqrestore(d->lockptr, *d->flags); +} +EXPORT_SYMBOL(lockptr_unlock_irqsave); /** * refcount_dec_and_lock_irqsave - return holding spinlock with disabled @@ -172,15 +212,13 @@ EXPORT_SYMBOL(refcount_dec_and_lock); bool refcount_dec_and_lock_irqsave(refcount_t *r, spinlock_t *lock, unsigned long *flags) { - if (refcount_dec_not_one(r)) - return false; + struct lockptr_irqsave_data d = { + .lockptr = lock, + .flags = flags, + }; - spin_lock_irqsave(lock, *flags); - if (!refcount_dec_and_test(r)) { - spin_unlock_irqrestore(lock, *flags); - return false; - } - - return true; + return refcount_dec_and_lockptr(r, lockptr_lock_irqsave, + lockptr_unlock_irqsave, &d); } EXPORT_SYMBOL(refcount_dec_and_lock_irqsave); + -- 2.39.3
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