On 7/30/2019 9:32 PM, Peter Zijlstra wrote:
On Tue, Jul 30, 2019 at 06:10:49PM +0530, Mukesh Ojha wrote:
To make it static , i have to export mutex_is_locked() after moving it
inside mutex.c, so that other module can use it.
Yep, see below -- completely untested.
Also are we thinking of removing
static inline /* __deprecated */ __must_check enum
mutex_trylock_recursive_enum
mutex_trylock_recursive(struct mutex *lock)
inside linux/mutex.h in future ?
As i see it is used at one or two places and there is a check inside
checkpatch guarding its further use .
That was the idea; recursive locking is evil, but we have these two
legacy sites.
---
diff --git a/include/linux/mutex.h b/include/linux/mutex.h
index dcd03fee6e01..eb8c62aba263 100644
--- a/include/linux/mutex.h
+++ b/include/linux/mutex.h
@@ -65,29 +65,6 @@ struct mutex {
#endif
};
-/*
- * Internal helper function; C doesn't allow us to hide it :/
- *
- * DO NOT USE (outside of mutex code).
- */
-static inline struct task_struct *__mutex_owner(struct mutex *lock)
-{
- return (struct task_struct *)(atomic_long_read(&lock->owner) & ~0x07);
-}
-
-/*
- * This is the control structure for tasks blocked on mutex,
- * which resides on the blocked task's kernel stack:
- */
-struct mutex_waiter {
- struct list_head list;
- struct task_struct *task;
- struct ww_acquire_ctx *ww_ctx;
-#ifdef CONFIG_DEBUG_MUTEXES
- void *magic;
-#endif
-};
-
#ifdef CONFIG_DEBUG_MUTEXES
#define __DEBUG_MUTEX_INITIALIZER(lockname) \
@@ -144,10 +121,7 @@ extern void __mutex_init(struct mutex *lock, const char
*name,
*
* Returns true if the mutex is locked, false if unlocked.
*/
-static inline bool mutex_is_locked(struct mutex *lock)
-{
- return __mutex_owner(lock) != NULL;
-}
+extern bool mutex_is_locked(struct mutex *lock);
/*
* See kernel/locking/mutex.c for detailed documentation of these APIs.
@@ -220,13 +194,7 @@ enum mutex_trylock_recursive_enum {
* - MUTEX_TRYLOCK_SUCCESS - lock acquired,
* - MUTEX_TRYLOCK_RECURSIVE - we already owned the lock.
*/
-static inline /* __deprecated */ __must_check enum mutex_trylock_recursive_enum
-mutex_trylock_recursive(struct mutex *lock)
-{
- if (unlikely(__mutex_owner(lock) == current))
- return MUTEX_TRYLOCK_RECURSIVE;
-
- return mutex_trylock(lock);
-}
+extern /* __deprecated */ __must_check enum mutex_trylock_recursive_enum
+mutex_trylock_recursive(struct mutex *lock);
#endif /* __LINUX_MUTEX_H */
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index 5e069734363c..2f73935a6053 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -36,6 +36,19 @@
# include "mutex.h"
#endif
+/*
+ * This is the control structure for tasks blocked on mutex,
+ * which resides on the blocked task's kernel stack:
+ */
+struct mutex_waiter {
+ struct list_head list;
+ struct task_struct *task;
+ struct ww_acquire_ctx *ww_ctx;
+#ifdef CONFIG_DEBUG_MUTEXES
+ void *magic;
+#endif
+};
i already did in v2 except this above waiter struct, will do it in v3.
Cheers,
Mukesh
+
void
__mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key)
{
@@ -65,6 +78,16 @@ EXPORT_SYMBOL(__mutex_init);
#define MUTEX_FLAGS 0x07
+/*
+ * Internal helper function; C doesn't allow us to hide it :/
+ *
+ * DO NOT USE (outside of mutex code).
+ */
+static inline struct task_struct *__mutex_owner(struct mutex *lock)
+{
+ return (struct task_struct *)(atomic_long_read(&lock->owner) &
~MUTEX_FLAGS);
+}
+
static inline struct task_struct *__owner_task(unsigned long owner)
{
return (struct task_struct *)(owner & ~MUTEX_FLAGS);
@@ -75,6 +98,22 @@ static inline unsigned long __owner_flags(unsigned long
owner)
return owner & MUTEX_FLAGS;
}
+bool mutex_is_locked(struct mutex *lock)
+{
+ return __mutex_owner(lock) != NULL;
+}
+EXPORT_SYMBOL(mutex_is_locked);
+
+__must_check enum mutex_trylock_recursive_enum
+mutex_trylock_recursive(struct mutex *lock)
+{
+ if (unlikely(__mutex_owner(lock) == current))
+ return MUTEX_TRYLOCK_RECURSIVE;
+
+ return mutex_trylock(lock);
+}
+EXPORT_SYMBOL(mutex_trylock_recursive);
+
/*
* Trylock variant that retuns the owning task on failure.
*/
