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Message-Id: <1507744922-15196-5-git-send-email-longman@redhat.com>
Date: Wed, 11 Oct 2017 14:01:55 -0400
From: Waiman Long <longman@...hat.com>
To: Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>
Cc: linux-kernel@...r.kernel.org, x86@...nel.org,
linux-alpha@...r.kernel.org, linux-ia64@...r.kernel.org,
linux-s390@...r.kernel.org, linux-arch@...r.kernel.org,
Davidlohr Bueso <dave@...olabs.net>,
Dave Chinner <david@...morbit.com>,
Waiman Long <longman@...hat.com>
Subject: [PATCH v6 04/11] locking/rwsem: Remove kernel/locking/rwsem.h
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@...hat.com>
---
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
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