[tip: locking/core] locking/rtmutex: Add rt_mutex_lock_nest_lock() and rt_mutex_lock_killable().

tip-bot2 for Sebastian Andrzej Siewior
2021-12-06T15:29:52Z

The following commit has been merged into the locking/core branch of tip:

Commit-ID: a3642021923b26d86bb27d88c826494827612c06
Gitweb: https://git.kernel.org/tip/a3642021923b26d86bb27d88c826494827612c06
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
AuthorDate: Mon, 29 Nov 2021 18:46:47 +01:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Sat, 04 Dec 2021 10:56:23 +01:00

locking/rtmutex: Add rt_mutex_lock_nest_lock() and rt_mutex_lock_killable().

The locking selftest for ww-mutex expects to operate directly on the
base-mutex which becomes a rtmutex on PREEMPT_RT.

Add a rtmutex based implementation of mutex_lock_nest_lock() and
mutex_lock_killable() named rt_mutex_lock_nest_lock() abd
rt_mutex_lock_killable().

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20211129174654.668506-5-bigeasy@linutronix.de
---
include/linux/rtmutex.h | 9 +++++++++
kernel/locking/rtmutex_api.c | 30 ++++++++++++++++++++++++++----
2 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/include/linux/rtmutex.h b/include/linux/rtmutex.h
index 9deedfe..7d04988 100644
--- a/include/linux/rtmutex.h
+++ b/include/linux/rtmutex.h
@@ -99,13 +99,22 @@ extern void __rt_mutex_init(struct rt_mutex *lock, const char *name, struct lock

#ifdef CONFIG_DEBUG_LOCK_ALLOC
extern void rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int subclass);
+extern void _rt_mutex_lock_nest_lock(struct rt_mutex *lock, struct lockdep_map *nest_lock);
#define rt_mutex_lock(lock) rt_mutex_lock_nested(lock, 0)
+#define rt_mutex_lock_nest_lock(lock, nest_lock) \
+ do { \
+ typecheck(struct lockdep_map *, &(nest_lock)->dep_map); \
+ _rt_mutex_lock_nest_lock(lock, &(nest_lock)->dep_map); \
+ } while (0)
+
#else
extern void rt_mutex_lock(struct rt_mutex *lock);
#define rt_mutex_lock_nested(lock, subclass) rt_mutex_lock(lock)
+#define rt_mutex_lock_nest_lock(lock, nest_lock) rt_mutex_lock(lock)
#endif

extern int rt_mutex_lock_interruptible(struct rt_mutex *lock);
+extern int rt_mutex_lock_killable(struct rt_mutex *lock);
extern int rt_mutex_trylock(struct rt_mutex *lock);

extern void rt_mutex_unlock(struct rt_mutex *lock);
diff --git a/kernel/locking/rtmutex_api.c b/kernel/locking/rtmutex_api.c
index 5c9299a..9002209 100644
--- a/kernel/locking/rtmutex_api.c
+++ b/kernel/locking/rtmutex_api.c
@@ -21,12 +21,13 @@ int max_lock_depth = 1024;
*/
static __always_inline int __rt_mutex_lock_common(struct rt_mutex *lock,
unsigned int state,
+ struct lockdep_map *nest_lock,
unsigned int subclass)
{
int ret;

might_sleep();
- mutex_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
+ mutex_acquire_nest(&lock->dep_map, subclass, 0, nest_lock, _RET_IP_);
ret = __rt_mutex_lock(&lock->rtmutex, state);
if (ret)
mutex_release(&lock->dep_map, _RET_IP_);
@@ -48,10 +49,16 @@ EXPORT_SYMBOL(rt_mutex_base_init);
*/
void __sched rt_mutex_lock_nested(struct rt_mutex *lock, unsigned int subclass)
{
- __rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, subclass);
+ __rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, NULL, subclass);
}
EXPORT_SYMBOL_GPL(rt_mutex_lock_nested);

+void __sched _rt_mutex_lock_nest_lock(struct rt_mutex *lock, struct lockdep_map *nest_lock)
+{
+ __rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, nest_lock, 0);
+}
+EXPORT_SYMBOL_GPL(_rt_mutex_lock_nest_lock);
+
#else /* !CONFIG_DEBUG_LOCK_ALLOC */

/**
@@ -61,7 +68,7 @@ EXPORT_SYMBOL_GPL(rt_mutex_lock_nested);
*/
void __sched rt_mutex_lock(struct rt_mutex *lock)
{
- __rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, 0);
+ __rt_mutex_lock_common(lock, TASK_UNINTERRUPTIBLE, NULL, 0);
}
EXPORT_SYMBOL_GPL(rt_mutex_lock);
#endif
@@ -77,11 +84,26 @@ EXPORT_SYMBOL_GPL(rt_mutex_lock);
*/
int __sched rt_mutex_lock_interruptible(struct rt_mutex *lock)
{
- return __rt_mutex_lock_common(lock, TASK_INTERRUPTIBLE, 0);
+ return __rt_mutex_lock_common(lock, TASK_INTERRUPTIBLE, NULL, 0);
}
EXPORT_SYMBOL_GPL(rt_mutex_lock_interruptible);

/**
+ * rt_mutex_lock_killable - lock a rt_mutex killable
+ *
+ * @lock: the rt_mutex to be locked
+ *
+ * Returns:
+ * 0 on success
+ * -EINTR when interrupted by a signal
+ */
+int __sched rt_mutex_lock_killable(struct rt_mutex *lock)
+{
+ return __rt_mutex_lock_common(lock, TASK_KILLABLE, NULL, 0);
+}
+EXPORT_SYMBOL_GPL(rt_mutex_lock_killable);
+
+/**
* rt_mutex_trylock - try to lock a rt_mutex
*
* @lock: the rt_mutex to be locked