[PATCH RT 13/15] rt/locking: allow recursive local_trylock()

From: Steven Rostedt
Date: Fri Dec 01 2017 - 10:57:16 EST


4.9.65-rt57-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>

required for following networking patch which does recursive try-lock.
While at it, add the !RT version of it because it did not yet exist.

Cc: rt-stable@xxxxxxxxxxxxxxx
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
---
include/linux/locallock.h | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/include/linux/locallock.h b/include/linux/locallock.h
index 845c77f1a5ca..280f884a05a3 100644
--- a/include/linux/locallock.h
+++ b/include/linux/locallock.h
@@ -77,6 +77,9 @@ static inline int __local_trylock(struct local_irq_lock *lv)
lv->owner = current;
lv->nestcnt = 1;
return 1;
+ } else if (lv->owner == current) {
+ lv->nestcnt++;
+ return 1;
}
return 0;
}
@@ -250,6 +253,12 @@ static inline int __local_unlock_irqrestore(struct local_irq_lock *lv,

static inline void local_irq_lock_init(int lvar) { }

+#define local_trylock(lvar) \
+ ({ \
+ preempt_disable(); \
+ 1; \
+ })
+
#define local_lock(lvar) preempt_disable()
#define local_unlock(lvar) preempt_enable()
#define local_lock_irq(lvar) local_irq_disable()
--
2.13.2