[PATCH 1/2] xen/spinlock: use lock address for lock debug functions

[Juergen Gross <jgross@xxxxxxxx>]

Instead of only passing the lock_debug address to check_lock() et al
use the address of the spinlock.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 xen/common/spinlock.c      | 34 +++++++++++++++++-----------------
 xen/include/xen/rwlock.h   | 10 +++++-----
 xen/include/xen/spinlock.h | 10 ++++++++--
 3 files changed, 30 insertions(+), 24 deletions(-)

diff --git a/xen/common/spinlock.c b/xen/common/spinlock.c
index 62c83aaa6a..53d6ab6853 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);
 
-void check_lock(union lock_debug *debug, bool try)
+void check_lock(spinlock_t *lock, bool try)
 {
     bool irq_safe = !local_irq_is_enabled();
 
@@ -49,12 +49,12 @@ void check_lock(union lock_debug *debug, bool try)
     if ( try && irq_safe )
         return;
 
-    if ( unlikely(debug->irq_safe != irq_safe) )
+    if ( unlikely(lock->debug.irq_safe != irq_safe) )
     {
         union lock_debug seen, new = { 0 };
 
         new.irq_safe = irq_safe;
-        seen.val = cmpxchg(&debug->val, LOCK_DEBUG_INITVAL, new.val);
+        seen.val = cmpxchg(&lock->debug.val, LOCK_DEBUG_INITVAL, new.val);
 
         if ( !seen.unseen && seen.irq_safe == !irq_safe )
         {
@@ -65,7 +65,7 @@ void check_lock(union lock_debug *debug, bool try)
     }
 }
 
-static void check_barrier(union lock_debug *debug)
+static void check_barrier(spinlock_t *lock)
 {
     if ( unlikely(atomic_read(&spin_debug) <= 0) )
         return;
@@ -81,19 +81,19 @@ static void check_barrier(union lock_debug *debug)
      * However, if we spin on an IRQ-unsafe lock with IRQs disabled then that
      * is clearly wrong, for the same reason outlined in check_lock() above.
      */
-    BUG_ON(!local_irq_is_enabled() && !debug->irq_safe);
+    BUG_ON(!local_irq_is_enabled() && !lock->debug.irq_safe);
 }
 
-static void got_lock(union lock_debug *debug)
+static void got_lock(spinlock_t *lock)
 {
-    debug->cpu = smp_processor_id();
+    lock->debug.cpu = smp_processor_id();
 }
 
-static void rel_lock(union lock_debug *debug)
+static void rel_lock(spinlock_t *lock)
 {
     if ( atomic_read(&spin_debug) > 0 )
-        BUG_ON(debug->cpu != smp_processor_id());
-    debug->cpu = SPINLOCK_NO_CPU;
+        BUG_ON(lock->debug.cpu != smp_processor_id());
+    lock->debug.cpu = SPINLOCK_NO_CPU;
 }
 
 void spin_debug_enable(void)
@@ -164,7 +164,7 @@ void inline _spin_lock_cb(spinlock_t *lock, void (*cb)(void 
*), void *data)
     spinlock_tickets_t tickets = SPINLOCK_TICKET_INC;
     LOCK_PROFILE_VAR;
 
-    check_lock(&lock->debug, false);
+    check_lock(lock, false);
     preempt_disable();
     tickets.head_tail = arch_fetch_and_add(&lock->tickets.head_tail,
                                            tickets.head_tail);
@@ -176,7 +176,7 @@ void inline _spin_lock_cb(spinlock_t *lock, void (*cb)(void 
*), void *data)
         arch_lock_relax();
     }
     arch_lock_acquire_barrier();
-    got_lock(&lock->debug);
+    got_lock(lock);
     LOCK_PROFILE_GOT;
 }
 
@@ -204,7 +204,7 @@ unsigned long _spin_lock_irqsave(spinlock_t *lock)
 void _spin_unlock(spinlock_t *lock)
 {
     LOCK_PROFILE_REL;
-    rel_lock(&lock->debug);
+    rel_lock(lock);
     arch_lock_release_barrier();
     add_sized(&lock->tickets.head, 1);
     arch_lock_signal();
@@ -240,7 +240,7 @@ int _spin_trylock(spinlock_t *lock)
     spinlock_tickets_t old, new;
 
     preempt_disable();
-    check_lock(&lock->debug, true);
+    check_lock(lock, true);
     old = observe_lock(&lock->tickets);
     if ( old.head != old.tail )
     {
@@ -259,7 +259,7 @@ int _spin_trylock(spinlock_t *lock)
      * cmpxchg() is a full barrier so no need for an
      * arch_lock_acquire_barrier().
      */
-    got_lock(&lock->debug);
+    got_lock(lock);
 #ifdef CONFIG_DEBUG_LOCK_PROFILE
     if (lock->profile)
         lock->profile->time_locked = NOW();
@@ -274,7 +274,7 @@ void _spin_barrier(spinlock_t *lock)
     s_time_t block = NOW();
 #endif
 
-    check_barrier(&lock->debug);
+    check_barrier(lock);
     smp_mb();
     sample = observe_lock(&lock->tickets);
     if ( sample.head != sample.tail )
@@ -300,7 +300,7 @@ int _spin_trylock_recursive(spinlock_t *lock)
     BUILD_BUG_ON(NR_CPUS > SPINLOCK_NO_CPU);
     BUILD_BUG_ON(SPINLOCK_RECURSE_BITS < 3);
 
-    check_lock(&lock->debug, true);
+    check_lock(lock, true);
 
     if ( likely(lock->recurse_cpu != cpu) )
     {
diff --git a/xen/include/xen/rwlock.h b/xen/include/xen/rwlock.h
index 0cc9167715..188fc809dc 100644
--- a/xen/include/xen/rwlock.h
+++ b/xen/include/xen/rwlock.h
@@ -56,7 +56,7 @@ static inline int _read_trylock(rwlock_t *lock)
     u32 cnts;
 
     preempt_disable();
-    check_lock(&lock->lock.debug, true);
+    check_lock(&lock->lock, true);
     cnts = atomic_read(&lock->cnts);
     if ( likely(_can_read_lock(cnts)) )
     {
@@ -90,7 +90,7 @@ static inline void _read_lock(rwlock_t *lock)
     if ( likely(_can_read_lock(cnts)) )
     {
         /* The slow path calls check_lock() via spin_lock(). */
-        check_lock(&lock->lock.debug, false);
+        check_lock(&lock->lock, false);
         return;
     }
 
@@ -169,7 +169,7 @@ static inline void _write_lock(rwlock_t *lock)
     if ( atomic_cmpxchg(&lock->cnts, 0, _write_lock_val()) == 0 )
     {
         /* The slow path calls check_lock() via spin_lock(). */
-        check_lock(&lock->lock.debug, false);
+        check_lock(&lock->lock, false);
         return;
     }
 
@@ -206,7 +206,7 @@ static inline int _write_trylock(rwlock_t *lock)
     u32 cnts;
 
     preempt_disable();
-    check_lock(&lock->lock.debug, true);
+    check_lock(&lock->lock, true);
     cnts = atomic_read(&lock->cnts);
     if ( unlikely(cnts) ||
          unlikely(atomic_cmpxchg(&lock->cnts, 0, _write_lock_val()) != 0) )
@@ -341,7 +341,7 @@ static inline void _percpu_read_lock(percpu_rwlock_t 
**per_cpudata,
     else
     {
         /* All other paths have implicit check_lock() calls via read_lock(). */
-        check_lock(&percpu_rwlock->rwlock.lock.debug, false);
+        check_lock(&percpu_rwlock->rwlock.lock, false);
     }
 }
 
diff --git a/xen/include/xen/spinlock.h b/xen/include/xen/spinlock.h
index 961891bea4..5b6b73732f 100644
--- a/xen/include/xen/spinlock.h
+++ b/xen/include/xen/spinlock.h
@@ -21,13 +21,11 @@ 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
@@ -189,6 +187,14 @@ int _spin_trylock_recursive(spinlock_t *lock);
 void _spin_lock_recursive(spinlock_t *lock);
 void _spin_unlock_recursive(spinlock_t *lock);
 
+#ifdef CONFIG_DEBUG_LOCKS
+void check_lock(spinlock_t *lock, bool try);
+#else
+static inline void check_lock(spinlock_t *lock, bool try)
+{
+}
+#endif
+
 #define spin_lock(l)                  _spin_lock(l)
 #define spin_lock_cb(l, c, d)         _spin_lock_cb(l, c, d)
 #define spin_lock_irq(l)              _spin_lock_irq(l)
-- 
2.34.1