[PATCH 2/2] kern/lock.h: XXX quiet GCC warnings about set but unused variables during simple locks

[Marin Ramesa]

* kern/lock.h (decl_simple_lock_data): Define macro.
(simple_unlock): Define so that lock is assigned to itself and add a comment 
saying why this was done.
(simple_lock_try): Define so that lock data is cast to a boolean with the value 
TRUE and assigned to itself. Add a comment saying why this was done.
* kern/sched_prim.c [!MACH_SLOCKS] (lock): Declare and initialize. 

---
 kern/lock.h       | 20 +++++++++++++++++---
 kern/sched_prim.c | 12 ++++++++++++++--
 2 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/kern/lock.h b/kern/lock.h
index 4f38ea3..f02ae8b 100644
--- a/kern/lock.h
+++ b/kern/lock.h
@@ -91,10 +91,13 @@ extern void         check_simple_locks(void);
 #endif /* NCPUS > 1 */
 
 #else  /* MACH_SLOCKS */
+
+#define        decl_simple_lock_data(class,name) \
+class simple_lock_t name;
+
 /*
  * Do not allocate storage for locks if not needed.
  */
-#define        decl_simple_lock_data(class,name)
 #define        simple_lock_addr(lock)          ((simple_lock_t)0)
 
 /*
@@ -102,8 +105,19 @@ extern void                check_simple_locks(void);
  */
 #define simple_lock_init(l)
 #define simple_lock(l)
-#define simple_unlock(l)
-#define simple_lock_try(l)     (TRUE)  /* always succeeds */
+
+/* Quiet GCC warnings about
+ * set but unused variables during
+ * simple_unlock().
+ */
+#define simple_unlock(l)       (*l = *l)
+
+/* Quiet GCC warnings about
+ * set but unused variables during
+ * simple_lock_try(). Always succeeds.
+ */
+#define simple_lock_try(l)     (*(boolean_t *)l->lock_data = *(boolean_t 
*)l->lock_data = TRUE)         
+
 #define simple_lock_taken(l)   (1)     /* always succeeds */
 #define check_simple_locks()
 #define simple_lock_pause()
diff --git a/kern/sched_prim.c b/kern/sched_prim.c
index 2946701..f91c5c9 100644
--- a/kern/sched_prim.c
+++ b/kern/sched_prim.c
@@ -238,6 +238,8 @@ void assert_wait(
        thread_t                thread;
 #if    MACH_SLOCKS
        simple_lock_t           lock;
+#else /* MACH_SLOCKS */
+       decl_simple_lock_data( , lock);
 #endif /* MACH_SLOCKS */
        spl_t                   s;
 
@@ -252,8 +254,10 @@ void assert_wait(
                q = &wait_queue[index];
 #if    MACH_SLOCKS
                lock = &wait_lock[index];
+#else /* MACH_SLOCKS */
+               lock = wait_lock[index];
 #endif /* MACH_SLOCKS */
                simple_lock(lock);
                thread_lock(thread);
                enqueue_tail(q, (queue_entry_t) thread);
@@ -296,6 +300,8 @@ void clear_wait(
        queue_t                 q;
 #if    MACH_SLOCKS
        simple_lock_t           lock;
+#else /* MACH_SLOCKS */
+       decl_simple_lock_data( , lock);
 #endif /* MACH_SLOCKS */
        event_t                 event;
        spl_t                   s;
@@ -318,6 +324,8 @@ void clear_wait(
                q = &wait_queue[index];
 #if    MACH_SLOCKS
                lock = &wait_lock[index];
+#else /* MACH_SLOCKS */
+               lock = wait_lock[index];
 #endif /* MACH_SLOCKS */
                simple_lock(lock);
                /*
@@ -399,6 +407,8 @@ void thread_wakeup_prim(
        thread_t                thread, next_th;
 #if    MACH_SLOCKS
        simple_lock_t           lock;
+#else /* MACH_SLOCKS */
+       decl_simple_lock_data( , lock);
 #endif  /* MACH_SLOCKS */
        spl_t                   s;
        int                     state;
@@ -408,6 +418,8 @@ void thread_wakeup_prim(
        s = splsched();
 #if    MACH_SLOCKS
        lock = &wait_lock[index];
+#else /* MACH_SLOCKS */
+       lock = wait_lock[index];
 #endif /* MACH_SLOCKS */
        simple_lock(lock);
        thread = (thread_t) queue_first(q);
-- 
1.8.1.4