diff options
Diffstat (limited to 'include/linux/seqlock.h')
| -rw-r--r-- | include/linux/seqlock.h | 464 |
1 files changed, 395 insertions, 69 deletions
diff --git a/include/linux/seqlock.h b/include/linux/seqlock.h index 54bc20496392..8c16a494c968 100644 --- a/include/linux/seqlock.h +++ b/include/linux/seqlock.h @@ -10,13 +10,17 @@ * * Copyrights: * - Based on x86_64 vsyscall gettimeofday: Keith Owens, Andrea Arcangeli + * - Sequence counters with associated locks, (C) 2020 Linutronix GmbH */ -#include <linux/spinlock.h> -#include <linux/preempt.h> -#include <linux/lockdep.h> #include <linux/compiler.h> #include <linux/kcsan-checks.h> +#include <linux/lockdep.h> +#include <linux/mutex.h> +#include <linux/preempt.h> +#include <linux/spinlock.h> +#include <linux/ww_mutex.h> + #include <asm/processor.h> /* @@ -48,6 +52,10 @@ * This mechanism can't be used if the protected data contains pointers, * as the writer can invalidate a pointer that a reader is following. * + * If the write serialization mechanism is one of the common kernel + * locking primitives, use a sequence counter with associated lock + * (seqcount_LOCKTYPE_t) instead. + * * If it's desired to automatically handle the sequence counter writer * serialization and non-preemptibility requirements, use a sequential * lock (seqlock_t) instead. @@ -108,9 +116,267 @@ static inline void seqcount_lockdep_reader_access(const seqcount_t *s) */ #define SEQCNT_ZERO(name) { .sequence = 0, SEQCOUNT_DEP_MAP_INIT(name) } +/* + * Sequence counters with associated locks (seqcount_LOCKTYPE_t) + * + * A sequence counter which associates the lock used for writer + * serialization at initialization time. This enables lockdep to validate + * that the write side critical section is properly serialized. + * + * For associated locks which do not implicitly disable preemption, + * preemption protection is enforced in the write side function. + * + * Lockdep is never used in any for the raw write variants. + * + * See Documentation/locking/seqlock.rst + */ + +#ifdef CONFIG_LOCKDEP +#define __SEQ_LOCKDEP(expr) expr +#else +#define __SEQ_LOCKDEP(expr) +#endif + +#define SEQCOUNT_LOCKTYPE_ZERO(seq_name, assoc_lock) { \ + .seqcount = SEQCNT_ZERO(seq_name.seqcount), \ + __SEQ_LOCKDEP(.lock = (assoc_lock)) \ +} + +#define seqcount_locktype_init(s, assoc_lock) \ +do { \ + seqcount_init(&(s)->seqcount); \ + __SEQ_LOCKDEP((s)->lock = (assoc_lock)); \ +} while (0) + +/** + * typedef seqcount_spinlock_t - sequence counter with spinlock associated + * @seqcount: The real sequence counter + * @lock: Pointer to the associated spinlock + * + * A plain sequence counter with external writer synchronization by a + * spinlock. The spinlock is associated to the sequence count in the + * static initializer or init function. This enables lockdep to validate + * that the write side critical section is properly serialized. + */ +typedef struct seqcount_spinlock { + seqcount_t seqcount; + __SEQ_LOCKDEP(spinlock_t *lock); +} seqcount_spinlock_t; + +/** + * SEQCNT_SPINLOCK_ZERO - static initializer for seqcount_spinlock_t + * @name: Name of the seqcount_spinlock_t instance + * @lock: Pointer to the associated spinlock + */ +#define SEQCNT_SPINLOCK_ZERO(name, lock) \ + SEQCOUNT_LOCKTYPE_ZERO(name, lock) + +/** + * seqcount_spinlock_init - runtime initializer for seqcount_spinlock_t + * @s: Pointer to the seqcount_spinlock_t instance + * @lock: Pointer to the associated spinlock + */ +#define seqcount_spinlock_init(s, lock) \ + seqcount_locktype_init(s, lock) + +/** + * typedef seqcount_raw_spinlock_t - sequence count with raw spinlock associated + * @seqcount: The real sequence counter + * @lock: Pointer to the associated raw spinlock + * + * A plain sequence counter with external writer synchronization by a + * raw spinlock. The raw spinlock is associated to the sequence count in + * the static initializer or init function. This enables lockdep to + * validate that the write side critical section is properly serialized. + */ +typedef struct seqcount_raw_spinlock { + seqcount_t seqcount; + __SEQ_LOCKDEP(raw_spinlock_t *lock); +} seqcount_raw_spinlock_t; + +/** + * SEQCNT_RAW_SPINLOCK_ZERO - static initializer for seqcount_raw_spinlock_t + * @name: Name of the seqcount_raw_spinlock_t instance + * @lock: Pointer to the associated raw_spinlock + */ +#define SEQCNT_RAW_SPINLOCK_ZERO(name, lock) \ + SEQCOUNT_LOCKTYPE_ZERO(name, lock) + +/** + * seqcount_raw_spinlock_init - runtime initializer for seqcount_raw_spinlock_t + * @s: Pointer to the seqcount_raw_spinlock_t instance + * @lock: Pointer to the associated raw_spinlock + */ +#define seqcount_raw_spinlock_init(s, lock) \ + seqcount_locktype_init(s, lock) + +/** + * typedef seqcount_rwlock_t - sequence count with rwlock associated + * @seqcount: The real sequence counter + * @lock: Pointer to the associated rwlock + * + * A plain sequence counter with external writer synchronization by a + * rwlock. The rwlock is associated to the sequence count in the static + * initializer or init function. This enables lockdep to validate that + * the write side critical section is properly serialized. + */ +typedef struct seqcount_rwlock { + seqcount_t seqcount; + __SEQ_LOCKDEP(rwlock_t *lock); +} seqcount_rwlock_t; + +/** + * SEQCNT_RWLOCK_ZERO - static initializer for seqcount_rwlock_t + * @name: Name of the seqcount_rwlock_t instance + * @lock: Pointer to the associated rwlock + */ +#define SEQCNT_RWLOCK_ZERO(name, lock) \ + SEQCOUNT_LOCKTYPE_ZERO(name, lock) + +/** + * seqcount_rwlock_init - runtime initializer for seqcount_rwlock_t + * @s: Pointer to the seqcount_rwlock_t instance + * @lock: Pointer to the associated rwlock + */ +#define seqcount_rwlock_init(s, lock) \ + seqcount_locktype_init(s, lock) + +/** + * typedef seqcount_mutex_t - sequence count with mutex associated + * @seqcount: The real sequence counter + * @lock: Pointer to the associated mutex + * + * A plain sequence counter with external writer synchronization by a + * mutex. The mutex is associated to the sequence counter in the static + * initializer or init function. This enables lockdep to validate that + * the write side critical section is properly serialized. + * + * The write side API functions write_seqcount_begin()/end() automatically + * disable and enable preemption when used with seqcount_mutex_t. + */ +typedef struct seqcount_mutex { + seqcount_t seqcount; + __SEQ_LOCKDEP(struct mutex *lock); +} seqcount_mutex_t; + +/** + * SEQCNT_MUTEX_ZERO - static initializer for seqcount_mutex_t + * @name: Name of the seqcount_mutex_t instance + * @lock: Pointer to the associated mutex + */ +#define SEQCNT_MUTEX_ZERO(name, lock) \ + SEQCOUNT_LOCKTYPE_ZERO(name, lock) + +/** + * seqcount_mutex_init - runtime initializer for seqcount_mutex_t + * @s: Pointer to the seqcount_mutex_t instance + * @lock: Pointer to the associated mutex + */ +#define seqcount_mutex_init(s, lock) \ + seqcount_locktype_init(s, lock) + +/** + * typedef seqcount_ww_mutex_t - sequence count with ww_mutex associated + * @seqcount: The real sequence counter + * @lock: Pointer to the associated ww_mutex + * + * A plain sequence counter with external writer synchronization by a + * ww_mutex. The ww_mutex is associated to the sequence counter in the static + * initializer or init function. This enables lockdep to validate that + * the write side critical section is properly serialized. + * + * The write side API functions write_seqcount_begin()/end() automatically + * disable and enable preemption when used with seqcount_ww_mutex_t. + */ +typedef struct seqcount_ww_mutex { + seqcount_t seqcount; + __SEQ_LOCKDEP(struct ww_mutex *lock); +} seqcount_ww_mutex_t; + +/** + * SEQCNT_WW_MUTEX_ZERO - static initializer for seqcount_ww_mutex_t + * @name: Name of the seqcount_ww_mutex_t instance + * @lock: Pointer to the associated ww_mutex + */ +#define SEQCNT_WW_MUTEX_ZERO(name, lock) \ + SEQCOUNT_LOCKTYPE_ZERO(name, lock) + +/** + * seqcount_ww_mutex_init - runtime initializer for seqcount_ww_mutex_t + * @s: Pointer to the seqcount_ww_mutex_t instance + * @lock: Pointer to the associated ww_mutex + */ +#define seqcount_ww_mutex_init(s, lock) \ + seqcount_locktype_init(s, lock) + +/* + * @preempt: Is the associated write serialization lock preemtpible? + */ +#define SEQCOUNT_LOCKTYPE(locktype, preempt, lockmember) \ +static inline seqcount_t * \ +__seqcount_##locktype##_ptr(seqcount_##locktype##_t *s) \ +{ \ + return &s->seqcount; \ +} \ + \ +static inline bool \ +__seqcount_##locktype##_preemptible(seqcount_##locktype##_t *s) \ +{ \ + return preempt; \ +} \ + \ +static inline void \ +__seqcount_##locktype##_assert(seqcount_##locktype##_t *s) \ +{ \ + __SEQ_LOCKDEP(lockdep_assert_held(lockmember)); \ +} + +/* + * Similar hooks, but for plain seqcount_t + */ + +static inline seqcount_t *__seqcount_ptr(seqcount_t *s) +{ + return s; +} + +static inline bool __seqcount_preemptible(seqcount_t *s) +{ + return false; +} + +static inline void __seqcount_assert(seqcount_t *s) +{ + lockdep_assert_preemption_disabled(); +} + +/* + * @s: Pointer to seqcount_locktype_t, generated hooks first parameter. + */ +SEQCOUNT_LOCKTYPE(raw_spinlock, false, s->lock) +SEQCOUNT_LOCKTYPE(spinlock, false, s->lock) +SEQCOUNT_LOCKTYPE(rwlock, false, s->lock) +SEQCOUNT_LOCKTYPE(mutex, true, s->lock) +SEQCOUNT_LOCKTYPE(ww_mutex, true, &s->lock->base) + +#define __seqprop_case(s, locktype, prop) \ + seqcount_##locktype##_t: __seqcount_##locktype##_##prop((void *)(s)) + +#define __seqprop(s, prop) _Generic(*(s), \ + seqcount_t: __seqcount_##prop((void *)(s)), \ + __seqprop_case((s), raw_spinlock, prop), \ + __seqprop_case((s), spinlock, prop), \ + __seqprop_case((s), rwlock, prop), \ + __seqprop_case((s), mutex, prop), \ + __seqprop_case((s), ww_mutex, prop)) + +#define __to_seqcount_t(s) __seqprop(s, ptr) +#define __associated_lock_exists_and_is_preemptible(s) __seqprop(s, preemptible) +#define __assert_write_section_is_protected(s) __seqprop(s, assert) + /** * __read_seqcount_begin() - begin a seqcount_t read section w/o barrier - * @s: Pointer to seqcount_t + * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants * * __read_seqcount_begin is like read_seqcount_begin, but has no smp_rmb() * barrier. Callers should ensure that smp_rmb() or equivalent ordering is @@ -122,7 +388,10 @@ static inline void seqcount_lockdep_reader_access(const seqcount_t *s) * * Return: count to be passed to read_seqcount_retry() */ -static inline unsigned __read_seqcount_begin(const seqcount_t *s) +#define __read_seqcount_begin(s) \ + __read_seqcount_t_begin(__to_seqcount_t(s)) + +static inline unsigned __read_seqcount_t_begin(const seqcount_t *s) { unsigned ret; @@ -138,32 +407,38 @@ repeat: /** * raw_read_seqcount_begin() - begin a seqcount_t read section w/o lockdep - * @s: Pointer to seqcount_t + * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants * * Return: count to be passed to read_seqcount_retry() */ -static inline unsigned raw_read_seqcount_begin(const seqcount_t *s) +#define raw_read_seqcount_begin(s) \ + raw_read_seqcount_t_begin(__to_seqcount_t(s)) + +static inline unsigned raw_read_seqcount_t_begin(const seqcount_t *s) { - unsigned ret = __read_seqcount_begin(s); + unsigned ret = __read_seqcount_t_begin(s); smp_rmb(); return ret; } /** * read_seqcount_begin() - begin a seqcount_t read critical section - * @s: Pointer to seqcount_t + * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants * * Return: count to be passed to read_seqcount_retry() */ -static inline unsigned read_seqcount_begin(const seqcount_t *s) +#define read_seqcount_begin(s) \ + read_seqcount_t_begin(__to_seqcount_t(s)) + +static inline unsigned read_seqcount_t_begin(const seqcount_t *s) { seqcount_lockdep_reader_access(s); - return raw_read_seqcount_begin(s); + return raw_read_seqcount_t_begin(s); } /** * raw_read_seqcount() - read the raw seqcount_t counter value - * @s: Pointer to seqcount_t + * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants * * raw_read_seqcount opens a read critical section of the given * seqcount_t, without any lockdep checking, and without checking or @@ -172,7 +447,10 @@ static inline unsigned read_seqcount_begin(const seqcount_t *s) * * Return: count to be passed to read_seqcount_retry() */ -static inline unsigned raw_read_seqcount(const seqcount_t *s) +#define raw_read_seqcount(s) \ + raw_read_seqcount_t(__to_seqcount_t(s)) + +static inline unsigned raw_read_seqcount_t(const seqcount_t *s) { unsigned ret = READ_ONCE(s->sequence); smp_rmb(); @@ -183,7 +461,7 @@ static inline unsigned raw_read_seqcount(const seqcount_t *s) /** * raw_seqcount_begin() - begin a seqcount_t read critical section w/o * lockdep and w/o counter stabilization - * @s: Pointer to seqcount_t + * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants * * raw_seqcount_begin opens a read critical section of the given * seqcount_t. Unlike read_seqcount_begin(), this function will not wait @@ -197,18 +475,21 @@ static inline unsigned raw_read_seqcount(const seqcount_t *s) * * Return: count to be passed to read_seqcount_retry() */ -static inline unsigned raw_seqcount_begin(const seqcount_t *s) +#define raw_seqcount_begin(s) \ + raw_seqcount_t_begin(__to_seqcount_t(s)) + +static inline unsigned raw_seqcount_t_begin(const seqcount_t *s) { /* * If the counter is odd, let read_seqcount_retry() fail * by decrementing the counter. */ - return raw_read_seqcount(s) & ~1; + return raw_read_seqcount_t(s) & ~1; } /** * __read_seqcount_retry() - end a seqcount_t read section w/o barrier - * @s: Pointer to seqcount_t + * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants * @start: count, from read_seqcount_begin() * * __read_seqcount_retry is like read_seqcount_retry, but has no smp_rmb() @@ -221,7 +502,10 @@ static inline unsigned raw_seqcount_begin(const seqcount_t *s) * * Return: true if a read section retry is required, else false */ -static inline int __read_seqcount_retry(const seqcount_t *s, unsigned start) +#define __read_seqcount_retry(s, start) \ + __read_seqcount_t_retry(__to_seqcount_t(s), start) + +static inline int __read_seqcount_t_retry(const seqcount_t *s, unsigned start) { kcsan_atomic_next(0); return unlikely(READ_ONCE(s->sequence) != start); @@ -229,7 +513,7 @@ static inline int __read_seqcount_retry(const seqcount_t *s, unsigned start) /** * read_seqcount_retry() - end a seqcount_t read critical section - * @s: Pointer to seqcount_t + * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants * @start: count, from read_seqcount_begin() * * read_seqcount_retry closes the read critical section of given @@ -238,17 +522,28 @@ static inline int __read_seqcount_retry(const seqcount_t *s, unsigned start) * * Return: true if a read section retry is required, else false */ -static inline int read_seqcount_retry(const seqcount_t *s, unsigned start) +#define read_seqcount_retry(s, start) \ + read_seqcount_t_retry(__to_seqcount_t(s), start) + +static inline int read_seqcount_t_retry(const seqcount_t *s, unsigned start) { smp_rmb(); - return __read_seqcount_retry(s, start); + return __read_seqcount_t_retry(s, start); } /** * raw_write_seqcount_begin() - start a seqcount_t write section w/o lockdep - * @s: Pointer to seqcount_t + * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants */ -static inline void raw_write_seqcount_begin(seqcount_t *s) +#define raw_write_seqcount_begin(s) \ +do { \ + if (__associated_lock_exists_and_is_preemptible(s)) \ + preempt_disable(); \ + \ + raw_write_seqcount_t_begin(__to_seqcount_t(s)); \ +} while (0) + +static inline void raw_write_seqcount_t_begin(seqcount_t *s) { kcsan_nestable_atomic_begin(); s->sequence++; @@ -257,49 +552,50 @@ static inline void raw_write_seqcount_begin(seqcount_t *s) /** * raw_write_seqcount_end() - end a seqcount_t write section w/o lockdep - * @s: Pointer to seqcount_t + * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants */ -static inline void raw_write_seqcount_end(seqcount_t *s) +#define raw_write_seqcount_end(s) \ +do { \ + raw_write_seqcount_t_end(__to_seqcount_t(s)); \ + \ + if (__associated_lock_exists_and_is_preemptible(s)) \ + preempt_enable(); \ +} while (0) + +static inline void raw_write_seqcount_t_end(seqcount_t *s) { smp_wmb(); s->sequence++; kcsan_nestable_atomic_end(); } -static inline void __write_seqcount_begin_nested(seqcount_t *s, int subclass) -{ - raw_write_seqcount_begin(s); - seqcount_acquire(&s->dep_map, subclass, 0, _RET_IP_); -} - /** * write_seqcount_begin_nested() - start a seqcount_t write section with * custom lockdep nesting level - * @s: Pointer to seqcount_t + * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants * @subclass: lockdep nesting level * * See Documentation/locking/lockdep-design.rst */ -static inline void write_seqcount_begin_nested(seqcount_t *s, int subclass) -{ - lockdep_assert_preemption_disabled(); - __write_seqcount_begin_nested(s, subclass); -} - -/* - * A write_seqcount_begin() variant w/o lockdep non-preemptibility checks. - * - * Use for internal seqlock.h code where it's known that preemption is - * already disabled. For example, seqlock_t write side functions. - */ -static inline void __write_seqcount_begin(seqcount_t *s) +#define write_seqcount_begin_nested(s, subclass) \ +do { \ + __assert_write_section_is_protected(s); \ + \ + if (__associated_lock_exists_and_is_preemptible(s)) \ + preempt_disable(); \ + \ + write_seqcount_t_begin_nested(__to_seqcount_t(s), subclass); \ +} while (0) + +static inline void write_seqcount_t_begin_nested(seqcount_t *s, int subclass) { - __write_seqcount_begin_nested(s, 0); + raw_write_seqcount_t_begin(s); + seqcount_acquire(&s->dep_map, subclass, 0, _RET_IP_); } /** * write_seqcount_begin() - start a seqcount_t write side critical section - * @s: Pointer to seqcount_t + * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants * * write_seqcount_begin opens a write side critical section of the given * seqcount_t. @@ -308,26 +604,44 @@ static inline void __write_seqcount_begin(seqcount_t *s) * non-preemptible. If readers can be invoked from hardirq or softirq * context, interrupts or bottom halves must be respectively disabled. */ -static inline void write_seqcount_begin(seqcount_t *s) +#define write_seqcount_begin(s) \ +do { \ + __assert_write_section_is_protected(s); \ + \ + if (__associated_lock_exists_and_is_preemptible(s)) \ + preempt_disable(); \ + \ + write_seqcount_t_begin(__to_seqcount_t(s)); \ +} while (0) + +static inline void write_seqcount_t_begin(seqcount_t *s) { - write_seqcount_begin_nested(s, 0); + write_seqcount_t_begin_nested(s, 0); } /** * write_seqcount_end() - end a seqcount_t write side critical section - * @s: Pointer to seqcount_t + * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants * * The write section must've been opened with write_seqcount_begin(). */ -static inline void write_seqcount_end(seqcount_t *s) +#define write_seqcount_end(s) \ +do { \ + write_seqcount_t_end(__to_seqcount_t(s)); \ + \ + if (__associated_lock_exists_and_is_preemptible(s)) \ + preempt_enable(); \ +} while (0) + +static inline void write_seqcount_t_end(seqcount_t *s) { seqcount_release(&s->dep_map, _RET_IP_); - raw_write_seqcount_end(s); + raw_write_seqcount_t_end(s); } /** * raw_write_seqcount_barrier() - do a seqcount_t write barrier - * @s: Pointer to seqcount_t + * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants * * This can be used to provide an ordering guarantee instead of the usual * consistency guarantee. It is one wmb cheaper, because it can collapse @@ -366,7 +680,10 @@ static inline void write_seqcount_end(seqcount_t *s) * WRITE_ONCE(X, false); * } */ -static inline void raw_write_seqcount_barrier(seqcount_t *s) +#define raw_write_seqcount_barrier(s) \ + raw_write_seqcount_t_barrier(__to_seqcount_t(s)) + +static inline void raw_write_seqcount_t_barrier(seqcount_t *s) { kcsan_nestable_atomic_begin(); s->sequence++; @@ -378,12 +695,15 @@ static inline void raw_write_seqcount_barrier(seqcount_t *s) /** * write_seqcount_invalidate() - invalidate in-progress seqcount_t read * side operations - * @s: Pointer to seqcount_t + * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants * * After write_seqcount_invalidate, no seqcount_t read side operations * will complete successfully and see data older than this. */ -static inline void write_seqcount_invalidate(seqcount_t *s) +#define write_seqcount_invalidate(s) \ + write_seqcount_t_invalidate(__to_seqcount_t(s)) + +static inline void write_seqcount_t_invalidate(seqcount_t *s) { smp_wmb(); kcsan_nestable_atomic_begin(); @@ -393,7 +713,7 @@ static inline void write_seqcount_invalidate(seqcount_t *s) /** * raw_read_seqcount_latch() - pick even/odd seqcount_t latch data copy - * @s: Pointer to seqcount_t + * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants * * Use seqcount_t latching to switch between two storage places protected * by a sequence counter. Doing so allows having interruptible, preemptible, @@ -406,7 +726,10 @@ static inline void write_seqcount_invalidate(seqcount_t *s) * picking which data copy to read. The full counter value must then be * checked with read_seqcount_retry(). */ -static inline int raw_read_seqcount_latch(seqcount_t *s) +#define raw_read_seqcount_latch(s) \ + raw_read_seqcount_t_latch(__to_seqcount_t(s)) + +static inline int raw_read_seqcount_t_latch(seqcount_t *s) { /* Pairs with the first smp_wmb() in raw_write_seqcount_latch() */ int seq = READ_ONCE(s->sequence); /* ^^^ */ @@ -415,7 +738,7 @@ static inline int raw_read_seqcount_latch(seqcount_t *s) /** * raw_write_seqcount_latch() - redirect readers to even/odd copy - * @s: Pointer to seqcount_t + * @s: Pointer to seqcount_t or any of the seqcount_locktype_t variants * * The latch technique is a multiversion concurrency control method that allows * queries during non-atomic modifications. If you can guarantee queries never @@ -494,7 +817,10 @@ static inline int raw_read_seqcount_latch(seqcount_t *s) * When data is a dynamic data structure; one should use regular RCU * patterns to manage the lifetimes of the objects within. */ -static inline void raw_write_seqcount_latch(seqcount_t *s) +#define raw_write_seqcount_latch(s) \ + raw_write_seqcount_t_latch(__to_seqcount_t(s)) + +static inline void raw_write_seqcount_t_latch(seqcount_t *s) { smp_wmb(); /* prior stores before incrementing "sequence" */ s->sequence++; @@ -592,7 +918,7 @@ static inline unsigned read_seqretry(const seqlock_t *sl, unsigned start) static inline void write_seqlock(seqlock_t *sl) { spin_lock(&sl->lock); - __write_seqcount_begin(&sl->seqcount); + write_seqcount_t_begin(&sl->seqcount); } /** @@ -604,7 +930,7 @@ static inline void write_seqlock(seqlock_t *sl) */ static inline void write_sequnlock(seqlock_t *sl) { - write_seqcount_end(&sl->seqcount); + write_seqcount_t_end(&sl->seqcount); spin_unlock(&sl->lock); } @@ -618,7 +944,7 @@ static inline void write_sequnlock(seqlock_t *sl) static inline void write_seqlock_bh(seqlock_t *sl) { spin_lock_bh(&sl->lock); - __write_seqcount_begin(&sl->seqcount); + write_seqcount_t_begin(&sl->seqcount); } /** @@ -631,7 +957,7 @@ static inline void write_seqlock_bh(seqlock_t *sl) */ static inline void write_sequnlock_bh(seqlock_t *sl) { - write_seqcount_end(&sl->seqcount); + write_seqcount_t_end(&sl->seqcount); spin_unlock_bh(&sl->lock); } @@ -645,7 +971,7 @@ static inline void write_sequnlock_bh(seqlock_t *sl) static inline void write_seqlock_irq(seqlock_t *sl) { spin_lock_irq(&sl->lock); - __write_seqcount_begin(&sl->seqcount); + write_seqcount_t_begin(&sl->seqcount); } /** @@ -657,7 +983,7 @@ static inline void write_seqlock_irq(seqlock_t *sl) */ static inline void write_sequnlock_irq(seqlock_t *sl) { - write_seqcount_end(&sl->seqcount); + write_seqcount_t_end(&sl->seqcount); spin_unlock_irq(&sl->lock); } @@ -666,7 +992,7 @@ static inline unsigned long __write_seqlock_irqsave(seqlock_t *sl) unsigned long flags; spin_lock_irqsave(&sl->lock, flags); - __write_seqcount_begin(&sl->seqcount); + write_seqcount_t_begin(&sl->seqcount); return flags; } @@ -695,13 +1021,13 @@ static inline unsigned long __write_seqlock_irqsave(seqlock_t *sl) static inline void write_sequnlock_irqrestore(seqlock_t *sl, unsigned long flags) { - write_seqcount_end(&sl->seqcount); + write_seqcount_t_end(&sl->seqcount); spin_unlock_irqrestore(&sl->lock, flags); } /** * read_seqlock_excl() - begin a seqlock_t locking reader section - * @sl: Pointer to seqlock_t + * @sl: Pointer to seqlock_t * * read_seqlock_excl opens a seqlock_t locking reader critical section. A * locking reader exclusively locks out *both* other writers *and* other |