[PATCH] add sem_is_read/write_locked()

Add sem_is_read/write_locked functions to the read/write semaphores, along the
same lines of the *_is_locked spinlock functions.  The swap token tuning patch
uses sem_is_read_locked; sem_is_write_locked is added for completeness.

Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

10 files changed, 50 insertions, 0 deletions

diff --git a/include/asm-alpha/rwsem.h b/include/asm-alpha/rwsem.h
index 8e058a67c9a48..fafdd4f7010a8 100644
--- a/include/asm-alpha/rwsem.h
+++ b/include/asm-alpha/rwsem.h
@@ -262,5 +262,10 @@ static inline long rwsem_atomic_update(long val, struct rw_semaphore *sem)
 #endif
 }
 
+static inline int rwsem_is_locked(struct rw_semaphore *sem)
+{
+	return (sem->count != 0);
+}
+
 #endif /* __KERNEL__ */
 #endif /* _ALPHA_RWSEM_H */
diff --git a/include/asm-i386/rwsem.h b/include/asm-i386/rwsem.h
index 7625a675852f8..be4ab859238ec 100644
--- a/include/asm-i386/rwsem.h
+++ b/include/asm-i386/rwsem.h
@@ -284,5 +284,10 @@ LOCK_PREFIX	"xadd %0,(%2)"
 	return tmp+delta;
 }
 
+static inline int rwsem_is_locked(struct rw_semaphore *sem)
+{
+	return (sem->count != 0);
+}
+
 #endif /* __KERNEL__ */
 #endif /* _I386_RWSEM_H */
diff --git a/include/asm-ia64/rwsem.h b/include/asm-ia64/rwsem.h
index e18b5ab0cb75c..1327c91ea39c7 100644
--- a/include/asm-ia64/rwsem.h
+++ b/include/asm-ia64/rwsem.h
@@ -186,4 +186,9 @@ __downgrade_write (struct rw_semaphore *sem)
 #define rwsem_atomic_add(delta, sem)	atomic64_add(delta, (atomic64_t *)(&(sem)->count))
 #define rwsem_atomic_update(delta, sem)	atomic64_add_return(delta, (atomic64_t *)(&(sem)->count))
 
+static inline int rwsem_is_locked(struct rw_semaphore *sem)
+{
+	return (sem->count != 0);
+}
+
 #endif /* _ASM_IA64_RWSEM_H */
diff --git a/include/asm-ppc/rwsem.h b/include/asm-ppc/rwsem.h
index 3e738f483c11b..3501ea72f88ce 100644
--- a/include/asm-ppc/rwsem.h
+++ b/include/asm-ppc/rwsem.h
@@ -168,5 +168,10 @@ static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem)
 	return atomic_add_return(delta, (atomic_t *)(&sem->count));
 }
 
+static inline int rwsem_is_locked(struct rw_semaphore *sem)
+{
+	return (sem->count != 0);
+}
+
 #endif /* __KERNEL__ */
 #endif /* _PPC_RWSEM_XADD_H */
diff --git a/include/asm-ppc64/rwsem.h b/include/asm-ppc64/rwsem.h
index bd5c2f0935753..7a647fae3765b 100644
--- a/include/asm-ppc64/rwsem.h
+++ b/include/asm-ppc64/rwsem.h
@@ -163,5 +163,10 @@ static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem)
 	return atomic_add_return(delta, (atomic_t *)(&sem->count));
 }
 
+static inline int rwsem_is_locked(struct rw_semaphore *sem)
+{
+	return (sem->count != 0);
+}
+
 #endif /* __KERNEL__ */
 #endif /* _PPC_RWSEM_XADD_H */
diff --git a/include/asm-s390/rwsem.h b/include/asm-s390/rwsem.h
index 8c0cebbfc034e..0422a085dd56a 100644
--- a/include/asm-s390/rwsem.h
+++ b/include/asm-s390/rwsem.h
@@ -351,5 +351,10 @@ static inline long rwsem_atomic_update(long delta, struct rw_semaphore *sem)
 	return new;
 }
 
+static inline int rwsem_is_locked(struct rw_semaphore *sem)
+{
+	return (sem->count != 0);
+}
+
 #endif /* __KERNEL__ */
 #endif /* _S390_RWSEM_H */
diff --git a/include/asm-sh/rwsem.h b/include/asm-sh/rwsem.h
index 1be4337f52595..0262d3d1e5e01 100644
--- a/include/asm-sh/rwsem.h
+++ b/include/asm-sh/rwsem.h
@@ -166,5 +166,10 @@ static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem)
 	return atomic_add_return(delta, (atomic_t *)(&sem->count));
 }
 
+static inline int rwsem_is_locked(struct rw_semaphore *sem)
+{
+	return (sem->count != 0);
+}
+
 #endif /* __KERNEL__ */
 #endif /* _ASM_SH_RWSEM_H */
diff --git a/include/asm-sparc64/rwsem.h b/include/asm-sparc64/rwsem.h
index 4568ee4022df0..cef5e8270421b 100644
--- a/include/asm-sparc64/rwsem.h
+++ b/include/asm-sparc64/rwsem.h
@@ -56,6 +56,11 @@ static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem)
 	atomic_add(delta, (atomic_t *)(&sem->count));
 }
 
+static inline int rwsem_is_locked(struct rw_semaphore *sem)
+{
+	return (sem->count != 0);
+}
+
 #endif /* __KERNEL__ */
 
 #endif /* _SPARC64_RWSEM_H */
diff --git a/include/asm-x86_64/rwsem.h b/include/asm-x86_64/rwsem.h
index c002175b6e82f..46077e9c1910b 100644
--- a/include/asm-x86_64/rwsem.h
+++ b/include/asm-x86_64/rwsem.h
@@ -274,5 +274,10 @@ LOCK_PREFIX	"xaddl %0,(%2)"
 	return tmp+delta;
 }
 
+static inline int rwsem_is_locked(struct rw_semaphore *sem)
+{
+	return (sem->count != 0);
+}
+
 #endif /* __KERNEL__ */
 #endif /* _X8664_RWSEM_H */
diff --git a/include/linux/rwsem-spinlock.h b/include/linux/rwsem-spinlock.h
index b52a2af25f1fb..f30f805080ae4 100644
--- a/include/linux/rwsem-spinlock.h
+++ b/include/linux/rwsem-spinlock.h
@@ -61,5 +61,10 @@ extern void FASTCALL(__up_read(struct rw_semaphore *sem));
 extern void FASTCALL(__up_write(struct rw_semaphore *sem));
 extern void FASTCALL(__downgrade_write(struct rw_semaphore *sem));
 
+static inline int rwsem_is_locked(struct rw_semaphore *sem)
+{
+	return (sem->activity != 0);
+}
+
 #endif /* __KERNEL__ */
 #endif /* _LINUX_RWSEM_SPINLOCK_H */