[PATCH 2/2] xen/rwlock: add check_lock() handling to rwlocks

[Juergen Gross <jgross@xxxxxxxx>]

Checking whether a lock is consistently used regarding interrupts on
or off is beneficial for rwlocks, too.

So add check_lock() calls to rwlock functions. For this purpose make
check_lock() globally accessible.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 xen/common/spinlock.c      |  3 +--
 xen/include/xen/rwlock.h   | 14 ++++++++++++++
 xen/include/xen/spinlock.h |  2 ++
 3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/xen/common/spinlock.c b/xen/common/spinlock.c
index 54f0c55dc2..acb3f86339 100644
--- a/xen/common/spinlock.c
+++ b/xen/common/spinlock.c
@@ -13,7 +13,7 @@
 
 static atomic_t spin_debug __read_mostly = ATOMIC_INIT(0);
 
-static void check_lock(union lock_debug *debug, bool try)
+void check_lock(union lock_debug *debug, bool try)
 {
     bool irq_safe = !local_irq_is_enabled();
 
@@ -108,7 +108,6 @@ void spin_debug_disable(void)
 
 #else /* CONFIG_DEBUG_LOCKS */
 
-#define check_lock(l, t) ((void)0)
 #define check_barrier(l) ((void)0)
 #define got_lock(l) ((void)0)
 #define rel_lock(l) ((void)0)
diff --git a/xen/include/xen/rwlock.h b/xen/include/xen/rwlock.h
index 427664037a..c302644705 100644
--- a/xen/include/xen/rwlock.h
+++ b/xen/include/xen/rwlock.h
@@ -65,7 +65,11 @@ static inline int _read_trylock(rwlock_t *lock)
          * arch_lock_acquire_barrier().
          */
         if ( likely(_can_read_lock(cnts)) )
+        {
+            check_lock(&lock->lock.debug, true);
             return 1;
+        }
+
         atomic_sub(_QR_BIAS, &lock->cnts);
     }
     preempt_enable();
@@ -87,7 +91,10 @@ static inline void _read_lock(rwlock_t *lock)
      * arch_lock_acquire_barrier().
      */
     if ( likely(_can_read_lock(cnts)) )
+    {
+        check_lock(&lock->lock.debug, false);
         return;
+    }
 
     /* The slowpath will decrement the reader count, if necessary. */
     queue_read_lock_slowpath(lock);
@@ -162,7 +169,10 @@ static inline void _write_lock(rwlock_t *lock)
      * arch_lock_acquire_barrier().
      */
     if ( atomic_cmpxchg(&lock->cnts, 0, _write_lock_val()) == 0 )
+    {
+        check_lock(&lock->lock.debug, false);
         return;
+    }
 
     queue_write_lock_slowpath(lock);
     /*
@@ -205,6 +215,8 @@ static inline int _write_trylock(rwlock_t *lock)
         return 0;
     }
 
+    check_lock(&lock->lock.debug, true);
+
     /*
      * atomic_cmpxchg() is a full barrier so no need for an
      * arch_lock_acquire_barrier().
@@ -328,6 +340,8 @@ static inline void _percpu_read_lock(percpu_rwlock_t 
**per_cpudata,
         /* Drop the read lock because we don't need it anymore. */
         read_unlock(&percpu_rwlock->rwlock);
     }
+    else
+        check_lock(&percpu_rwlock->rwlock.lock.debug, false);
 }
 
 static inline void _percpu_read_unlock(percpu_rwlock_t **per_cpudata,
diff --git a/xen/include/xen/spinlock.h b/xen/include/xen/spinlock.h
index ca13b600a0..9fa4e600c1 100644
--- a/xen/include/xen/spinlock.h
+++ b/xen/include/xen/spinlock.h
@@ -21,11 +21,13 @@ union lock_debug {
     };
 };
 #define _LOCK_DEBUG { LOCK_DEBUG_INITVAL }
+void check_lock(union lock_debug *debug, bool try);
 void spin_debug_enable(void);
 void spin_debug_disable(void);
 #else
 union lock_debug { };
 #define _LOCK_DEBUG { }
+#define check_lock(l, t) ((void)0)
 #define spin_debug_enable() ((void)0)
 #define spin_debug_disable() ((void)0)
 #endif
-- 
2.26.2