Add an interruptible version of down_write. It's the other
side of the already implemented down_read_interruptible.
It allows drivers which used custom locking code to
support interruptible rw semaphores to switch over
to rwsem.
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
---
include/linux/rwsem.h | 1 +
kernel/locking/rwsem.c | 23 +++++++++++++++++++++++
2 files changed, 24 insertions(+)
diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h
index 4c715be48717..753ae2cb8677 100644
--- a/include/linux/rwsem.h
+++ b/include/linux/rwsem.h
@@ -135,6 +135,7 @@ extern int down_read_trylock(struct rw_semaphore *sem);
* lock for writing
*/
extern void down_write(struct rw_semaphore *sem);
+extern int __must_check down_write_interruptible(struct rw_semaphore *sem);
extern int __must_check down_write_killable(struct rw_semaphore *sem);
/*
diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index abba5df50006..0eadd20347de 100644
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -1270,6 +1270,11 @@ static inline void __down_write(struct rw_semaphore *sem)
__down_write_common(sem, TASK_UNINTERRUPTIBLE);
}
+static inline int __down_write_interruptible(struct rw_semaphore *sem)
+{
+ return __down_write_common(sem, TASK_INTERRUPTIBLE);
+}
+
static inline int __down_write_killable(struct rw_semaphore *sem)
{
return __down_write_common(sem, TASK_KILLABLE);
@@ -1408,6 +1413,24 @@ void __sched down_write(struct rw_semaphore *sem)
}
EXPORT_SYMBOL(down_write);
+/*
+ * interruptible lock for writing
+ */
+int __sched down_write_interruptible(struct rw_semaphore *sem)
+{
+ might_sleep();
+ rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);
+
+ if (LOCK_CONTENDED_RETURN(sem, __down_write_trylock,
+ __down_write_interruptible)) {
+ rwsem_release(&sem->dep_map, _RET_IP_);
+ return -EINTR;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(down_write_interruptible);
+
/*
* lock for writing
*/
--
2.27.0
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