Merge branch 'next' into for-linus

Prepare input updates for 5.4 merge window.

1 files changed, 10 insertions, 8 deletions

diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h
index 2ea18a3def04..9d9c663987d8 100644
--- a/include/linux/rwsem.h
+++ b/include/linux/rwsem.h
@@ -34,12 +34,13 @@
  */
 struct rw_semaphore {
 	atomic_long_t count;
-#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
 	/*
-	 * Write owner. Used as a speculative check to see
-	 * if the owner is running on the cpu.
+	 * Write owner or one of the read owners as well flags regarding
+	 * the current state of the rwsem. Can be used as a speculative
+	 * check to see if the write owner is running on the cpu.
 	 */
-	struct task_struct *owner;
+	atomic_long_t owner;
+#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
 	struct optimistic_spin_queue osq; /* spinner MCS lock */
 #endif
 	raw_spinlock_t wait_lock;
@@ -50,10 +51,10 @@ struct rw_semaphore {
 };
 
 /*
- * Setting bit 1 of the owner field but not bit 0 will indicate
+ * Setting all bits of the owner field except bit 0 will indicate
  * that the rwsem is writer-owned with an unknown owner.
  */
-#define RWSEM_OWNER_UNKNOWN	((struct task_struct *)-2L)
+#define RWSEM_OWNER_UNKNOWN	(-2L)
 
 /* In all implementations count != 0 means locked */
 static inline int rwsem_is_locked(struct rw_semaphore *sem)
@@ -73,13 +74,14 @@ static inline int rwsem_is_locked(struct rw_semaphore *sem)
 #endif
 
 #ifdef CONFIG_RWSEM_SPIN_ON_OWNER
-#define __RWSEM_OPT_INIT(lockname) , .osq = OSQ_LOCK_UNLOCKED, .owner = NULL
+#define __RWSEM_OPT_INIT(lockname) , .osq = OSQ_LOCK_UNLOCKED
 #else
 #define __RWSEM_OPT_INIT(lockname)
 #endif
 
 #define __RWSEM_INITIALIZER(name)				\
 	{ __RWSEM_INIT_COUNT(name),				\
+	  .owner = ATOMIC_LONG_INIT(0),				\
 	  .wait_list = LIST_HEAD_INIT((name).wait_list),	\
 	  .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock)	\
 	  __RWSEM_OPT_INIT(name)				\
@@ -158,7 +160,7 @@ extern void downgrade_write(struct rw_semaphore *sem);
  * static then another method for expressing nested locking is
  * the explicit definition of lock class keys and the use of
  * lockdep_set_class() at lock initialization time.
- * See Documentation/locking/lockdep-design.txt for more details.)
+ * See Documentation/locking/lockdep-design.rst for more details.)
  */
 extern void down_read_nested(struct rw_semaphore *sem, int subclass);
 extern void down_write_nested(struct rw_semaphore *sem, int subclass);