[tip:locking/rwsem] locking/rwsem: Get rid of __down_write_nested()

[tip-bot for Michal Hocko]

Commit-ID:  f8e04d854506ddfeba9cb41b601972b28521f104
Gitweb:     http://git.kernel.org/tip/f8e04d854506ddfeba9cb41b601972b28521f104
Author:     Michal Hocko <mhocko@xxxxxxxx>
AuthorDate: Thu, 7 Apr 2016 17:12:21 +0200
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 13 Apr 2016 10:42:16 +0200

locking/rwsem: Get rid of __down_write_nested()

This is no longer used anywhere and all callers (__down_write()) use
0 as a subclass. Ditch __down_write_nested() to make the code easier
to follow.

This shouldn't introduce any functional change.

Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
Acked-by: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Chris Zankel <chris@xxxxxxxxxx>
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Max Filippov <jcmvbkbc@xxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx>
Cc: Signed-off-by: Jason Low <jason.low2@xxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: linux-alpha@xxxxxxxxxxxxxxx
Cc: linux-arch@xxxxxxxxxxxxxxx
Cc: linux-ia64@xxxxxxxxxxxxxxx
Cc: linux-s390@xxxxxxxxxxxxxxx
Cc: linux-sh@xxxxxxxxxxxxxxx
Cc: linux-xtensa@xxxxxxxxxxxxxxxx
Cc: sparclinux@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1460041951-22347-2-git-send-email-mhocko@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 arch/s390/include/asm/rwsem.h   | 7 +------
 arch/sh/include/asm/rwsem.h     | 5 -----
 arch/sparc/include/asm/rwsem.h  | 7 +------
 arch/x86/include/asm/rwsem.h    | 7 +------
 include/asm-generic/rwsem.h     | 7 +------
 include/linux/rwsem-spinlock.h  | 1 -
 kernel/locking/rwsem-spinlock.c | 7 +------
 7 files changed, 5 insertions(+), 36 deletions(-)

diff --git a/arch/s390/include/asm/rwsem.h b/arch/s390/include/asm/rwsem.h
index fead491..555d23b 100644
--- a/arch/s390/include/asm/rwsem.h
+++ b/arch/s390/include/asm/rwsem.h
@@ -90,7 +90,7 @@ static inline int __down_read_trylock(struct rw_semaphore *sem)
 /*
  * lock for writing
  */
-static inline void __down_write_nested(struct rw_semaphore *sem, int subclass)
+static inline void __down_write(struct rw_semaphore *sem)
 {
 	signed long old, new, tmp;
 
@@ -108,11 +108,6 @@ static inline void __down_write_nested(struct rw_semaphore *sem, int subclass)
 		rwsem_down_write_failed(sem);
 }
 
-static inline void __down_write(struct rw_semaphore *sem)
-{
-	__down_write_nested(sem, 0);
-}
-
 /*
  * trylock for writing -- returns 1 if successful, 0 if contention
  */
diff --git a/arch/sh/include/asm/rwsem.h b/arch/sh/include/asm/rwsem.h
index edab572..a5104be 100644
--- a/arch/sh/include/asm/rwsem.h
+++ b/arch/sh/include/asm/rwsem.h
@@ -114,11 +114,6 @@ static inline void __downgrade_write(struct rw_semaphore *sem)
 		rwsem_downgrade_wake(sem);
 }
 
-static inline void __down_write_nested(struct rw_semaphore *sem, int subclass)
-{
-	__down_write(sem);
-}
-
 /*
  * implement exchange and add functionality
  */
diff --git a/arch/sparc/include/asm/rwsem.h b/arch/sparc/include/asm/rwsem.h
index 069bf4d..e5a0d57 100644
--- a/arch/sparc/include/asm/rwsem.h
+++ b/arch/sparc/include/asm/rwsem.h
@@ -45,7 +45,7 @@ static inline int __down_read_trylock(struct rw_semaphore *sem)
 /*
  * lock for writing
  */
-static inline void __down_write_nested(struct rw_semaphore *sem, int subclass)
+static inline void __down_write(struct rw_semaphore *sem)
 {
 	long tmp;
 
@@ -55,11 +55,6 @@ static inline void __down_write_nested(struct rw_semaphore *sem, int subclass)
 		rwsem_down_write_failed(sem);
 }
 
-static inline void __down_write(struct rw_semaphore *sem)
-{
-	__down_write_nested(sem, 0);
-}
-
 static inline int __down_write_trylock(struct rw_semaphore *sem)
 {
 	long tmp;
diff --git a/arch/x86/include/asm/rwsem.h b/arch/x86/include/asm/rwsem.h
index ceec86eb..4a8292a 100644
--- a/arch/x86/include/asm/rwsem.h
+++ b/arch/x86/include/asm/rwsem.h
@@ -99,7 +99,7 @@ static inline int __down_read_trylock(struct rw_semaphore *sem)
 /*
  * lock for writing
  */
-static inline void __down_write_nested(struct rw_semaphore *sem, int subclass)
+static inline void __down_write(struct rw_semaphore *sem)
 {
 	long tmp;
 	asm volatile("# beginning down_write\n\t"
@@ -116,11 +116,6 @@ static inline void __down_write_nested(struct rw_semaphore *sem, int subclass)
 		     : "memory", "cc");
 }
 
-static inline void __down_write(struct rw_semaphore *sem)
-{
-	__down_write_nested(sem, 0);
-}
-
 /*
  * trylock for writing -- returns 1 if successful, 0 if contention
  */
diff --git a/include/asm-generic/rwsem.h b/include/asm-generic/rwsem.h
index d6d5dc9..b8d8a6c 100644
--- a/include/asm-generic/rwsem.h
+++ b/include/asm-generic/rwsem.h
@@ -53,7 +53,7 @@ static inline int __down_read_trylock(struct rw_semaphore *sem)
 /*
  * lock for writing
  */
-static inline void __down_write_nested(struct rw_semaphore *sem, int subclass)
+static inline void __down_write(struct rw_semaphore *sem)
 {
 	long tmp;
 
@@ -63,11 +63,6 @@ static inline void __down_write_nested(struct rw_semaphore *sem, int subclass)
 		rwsem_down_write_failed(sem);
 }
 
-static inline void __down_write(struct rw_semaphore *sem)
-{
-	__down_write_nested(sem, 0);
-}
-
 static inline int __down_write_trylock(struct rw_semaphore *sem)
 {
 	long tmp;
diff --git a/include/linux/rwsem-spinlock.h b/include/linux/rwsem-spinlock.h
index 561e861..a733a54 100644
--- a/include/linux/rwsem-spinlock.h
+++ b/include/linux/rwsem-spinlock.h
@@ -34,7 +34,6 @@ struct rw_semaphore {
 extern void __down_read(struct rw_semaphore *sem);
 extern int __down_read_trylock(struct rw_semaphore *sem);
 extern void __down_write(struct rw_semaphore *sem);
-extern void __down_write_nested(struct rw_semaphore *sem, int subclass);
 extern int __down_write_trylock(struct rw_semaphore *sem);
 extern void __up_read(struct rw_semaphore *sem);
 extern void __up_write(struct rw_semaphore *sem);
diff --git a/kernel/locking/rwsem-spinlock.c b/kernel/locking/rwsem-spinlock.c
index 3a50485..bab2610 100644
--- a/kernel/locking/rwsem-spinlock.c
+++ b/kernel/locking/rwsem-spinlock.c
@@ -191,7 +191,7 @@ int __down_read_trylock(struct rw_semaphore *sem)
 /*
  * get a write lock on the semaphore
  */
-void __sched __down_write_nested(struct rw_semaphore *sem, int subclass)
+void __sched __down_write(struct rw_semaphore *sem)
 {
 	struct rwsem_waiter waiter;
 	struct task_struct *tsk;
@@ -227,11 +227,6 @@ void __sched __down_write_nested(struct rw_semaphore *sem, int subclass)
 	raw_spin_unlock_irqrestore(&sem->wait_lock, flags);
 }
 
-void __sched __down_write(struct rw_semaphore *sem)
-{
-	__down_write_nested(sem, 0);
-}
-
 /*
  * trylock for writing -- returns 1 if successful, 0 if contention
  */