The content of kernel/locking/rwsem.h is now specific to rwsem-xadd. So we can just move the its content into rwsem-xadd.h and remove it. Signed-off-by: Waiman Long <longman@xxxxxxxxxx> --- kernel/locking/percpu-rwsem.c | 4 ++- kernel/locking/rwsem-xadd.c | 2 +- kernel/locking/rwsem-xadd.h | 66 +++++++++++++++++++++++++++++++++++++++++ kernel/locking/rwsem.c | 4 ++- kernel/locking/rwsem.h | 69 ------------------------------------------- 5 files changed, 73 insertions(+), 72 deletions(-) delete mode 100644 kernel/locking/rwsem.h diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c index f17dad9..d06f7c3 100644 --- a/kernel/locking/percpu-rwsem.c +++ b/kernel/locking/percpu-rwsem.c @@ -7,7 +7,9 @@ #include <linux/sched.h> #include <linux/errno.h> -#include "rwsem.h" +#ifdef CONFIG_RWSEM_XCHGADD_ALGORITHM +#include "rwsem-xadd.h" +#endif int __percpu_init_rwsem(struct percpu_rw_semaphore *sem, const char *name, struct lock_class_key *rwsem_key) diff --git a/kernel/locking/rwsem-xadd.c b/kernel/locking/rwsem-xadd.c index 30bc163..e3ab430 100644 --- a/kernel/locking/rwsem-xadd.c +++ b/kernel/locking/rwsem-xadd.c @@ -18,7 +18,7 @@ #include <linux/sched/debug.h> #include <linux/osq_lock.h> -#include "rwsem.h" +#include "rwsem-xadd.h" /* * Guide to the rw_semaphore's count field. diff --git a/kernel/locking/rwsem-xadd.h b/kernel/locking/rwsem-xadd.h index abcb484..4c19539 100644 --- a/kernel/locking/rwsem-xadd.h +++ b/kernel/locking/rwsem-xadd.h @@ -4,6 +4,72 @@ #include <linux/rwsem.h> /* + * The owner field of the rw_semaphore structure will be set to + * RWSEM_READ_OWNED when a reader grabs the lock. A writer will clear + * the owner field when it unlocks. A reader, on the other hand, will + * not touch the owner field when it unlocks. + * + * In essence, the owner field now has the following 3 states: + * 1) 0 + * - lock is free or the owner hasn't set the field yet + * 2) RWSEM_READER_OWNED + * - lock is currently or previously owned by readers (lock is free + * or not set by owner yet) + * 3) Other non-zero value + * - a writer owns the lock + */ +#define RWSEM_READER_OWNED ((struct task_struct *)1UL) + +#ifdef CONFIG_RWSEM_SPIN_ON_OWNER +/* + * All writes to owner are protected by WRITE_ONCE() to make sure that + * store tearing can't happen as optimistic spinners may read and use + * the owner value concurrently without lock. Read from owner, however, + * may not need READ_ONCE() as long as the pointer value is only used + * for comparison and isn't being dereferenced. + */ +static inline void rwsem_set_owner(struct rw_semaphore *sem) +{ + WRITE_ONCE(sem->owner, current); +} + +static inline void rwsem_clear_owner(struct rw_semaphore *sem) +{ + WRITE_ONCE(sem->owner, NULL); +} + +/* + * This should only be called by the first reader that acquires the read lock. + */ +static inline void rwsem_set_reader_owned(struct rw_semaphore *sem) +{ + WRITE_ONCE(sem->owner, RWSEM_READER_OWNED); +} + +static inline bool rwsem_owner_is_writer(struct task_struct *owner) +{ + return owner && owner != RWSEM_READER_OWNED; +} + +static inline bool rwsem_owner_is_reader(struct task_struct *owner) +{ + return owner == RWSEM_READER_OWNED; +} +#else +static inline void rwsem_set_owner(struct rw_semaphore *sem) +{ +} + +static inline void rwsem_clear_owner(struct rw_semaphore *sem) +{ +} + +static inline void rwsem_set_reader_owned(struct rw_semaphore *sem) +{ +} +#endif + +/* * The definition of the atomic counter in the semaphore: * * Bit 0 - writer locked bit diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c index 0a32725..2ad3af8 100644 --- a/kernel/locking/rwsem.c +++ b/kernel/locking/rwsem.c @@ -12,7 +12,9 @@ #include <linux/rwsem.h> #include <linux/atomic.h> -#include "rwsem.h" +#ifdef CONFIG_RWSEM_XCHGADD_ALGORITHM +#include "rwsem-xadd.h" +#endif /* * lock for reading diff --git a/kernel/locking/rwsem.h b/kernel/locking/rwsem.h deleted file mode 100644 index 612109f..0000000 --- a/kernel/locking/rwsem.h +++ /dev/null @@ -1,69 +0,0 @@ -/* - * The owner field of the rw_semaphore structure will be set to - * RWSEM_READ_OWNED when a reader grabs the lock. A writer will clear - * the owner field when it unlocks. A reader, on the other hand, will - * not touch the owner field when it unlocks. - * - * In essence, the owner field now has the following 3 states: - * 1) 0 - * - lock is free or the owner hasn't set the field yet - * 2) RWSEM_READER_OWNED - * - lock is currently or previously owned by readers (lock is free - * or not set by owner yet) - * 3) Other non-zero value - * - a writer owns the lock - */ -#define RWSEM_READER_OWNED ((struct task_struct *)1UL) - -#ifdef CONFIG_RWSEM_SPIN_ON_OWNER -/* - * All writes to owner are protected by WRITE_ONCE() to make sure that - * store tearing can't happen as optimistic spinners may read and use - * the owner value concurrently without lock. Read from owner, however, - * may not need READ_ONCE() as long as the pointer value is only used - * for comparison and isn't being dereferenced. - */ -static inline void rwsem_set_owner(struct rw_semaphore *sem) -{ - WRITE_ONCE(sem->owner, current); -} - -static inline void rwsem_clear_owner(struct rw_semaphore *sem) -{ - WRITE_ONCE(sem->owner, NULL); -} - -/* - * This should only be called by the first reader that acquires the read lock. - */ -static inline void rwsem_set_reader_owned(struct rw_semaphore *sem) -{ - WRITE_ONCE(sem->owner, RWSEM_READER_OWNED); -} - -static inline bool rwsem_owner_is_writer(struct task_struct *owner) -{ - return owner && owner != RWSEM_READER_OWNED; -} - -static inline bool rwsem_owner_is_reader(struct task_struct *owner) -{ - return owner == RWSEM_READER_OWNED; -} -#else -static inline void rwsem_set_owner(struct rw_semaphore *sem) -{ -} - -static inline void rwsem_clear_owner(struct rw_semaphore *sem) -{ -} - -static inline void rwsem_set_reader_owned(struct rw_semaphore *sem) -{ -} -#endif - -#ifdef CONFIG_RWSEM_XCHGADD_ALGORITHM -#include "rwsem-xadd.h" -#endif -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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