Introduce macro stubs in the mutex implementation that will be always

defined and will allow consumers, willing to provide options, file and
line to locking requests, to not worry about options redefining the
interfaces.
This is typically useful when there is the need to build another
locking interface on top of the mutex one.

The introduced functions that consumers can use are:
- mtx_lock_flags_
- mtx_unlock_flags_
- mtx_lock_spin_flags_
- mtx_unlock_spin_flags_
- mtx_assert_
- thread_lock_flags_

Spare notes:
- Likely we can get rid of all the 'INVARIANTS' specification in the
  ppbus code by using the same macro as done in this patch (but this is
  left to the ppbus maintainer)
- all the other locking interfaces may require a similar cleanup, where
  the most notable case is sx which will allow a further cleanup of
  vm_map locking facilities
- The patch should be fully compatible with older branches, thus a MFC
  is previewed (infact it uses all the underlying mechanisms already
  present).

Comments review by:	eadler, Ben Kaduk
Discussed with:		kib, jhb
MFC after:	1 month

1 files changed, 45 insertions, 30 deletions

diff --git a/sys/sys/mutex.h b/sys/sys/mutex.h
index 7a9d5d7..1e88e10 100644
--- a/sys/sys/mutex.h
+++ b/sys/sys/mutex.h
@@ -81,6 +81,10 @@
  *	 of the kernel via macros, thus allowing us to use the cpp LOCK_FILE
  *	 and LOCK_LINE. These functions should not be called directly by any
  *	 code using the API. Their macros cover their functionality.
+ *	 Functions with a `_' suffix are the entrypoint for the common
+ *	 KPI covering both compat shims and fast path case.  These can be
+ *	 used by consumers willing to pass options, file and line
+ *	 informations, in an option-independent way.
  *
  * [See below for descriptions]
  *
@@ -88,6 +92,8 @@
 void	mtx_init(struct mtx *m, const char *name, const char *type, int opts);
 void	mtx_destroy(struct mtx *m);
 void	mtx_sysinit(void *arg);
+int	mtx_trylock_flags_(struct mtx *m, int opts, const char *file,
+	    int line);
 void	mutex_init(void);
 void	_mtx_lock_sleep(struct mtx *m, uintptr_t tid, int opts,
 	    const char *file, int line);
@@ -97,7 +103,6 @@ void	_mtx_lock_spin(struct mtx *m, uintptr_t tid, int opts,
 	    const char *file, int line);
 #endif
 void	_mtx_unlock_spin(struct mtx *m, int opts, const char *file, int line);
-int	_mtx_trylock(struct mtx *m, int opts, const char *file, int line);
 void	_mtx_lock_flags(struct mtx *m, int opts, const char *file, int line);
 void	_mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line);
 void	_mtx_lock_spin_flags(struct mtx *m, int opts, const char *file,
@@ -107,12 +112,12 @@ void	_mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file,
 #if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
 void	_mtx_assert(const struct mtx *m, int what, const char *file, int line);
 #endif
-void	_thread_lock_flags(struct thread *, int, const char *, int);
+void	thread_lock_flags_(struct thread *, int, const char *, int);
 
 #define	thread_lock(tdp)						\
-    _thread_lock_flags((tdp), 0, __FILE__, __LINE__)
+	thread_lock_flags_((tdp), 0, __FILE__, __LINE__)
 #define	thread_lock_flags(tdp, opt)					\
-    _thread_lock_flags((tdp), (opt), __FILE__, __LINE__)
+	thread_lock_flags_((tdp), (opt), __FILE__, __LINE__)
 #define	thread_unlock(tdp)						\
        mtx_unlock_spin((tdp)->td_lock)
 
@@ -290,27 +295,48 @@ extern struct mtx_pool *mtxpool_sleep;
 #error LOCK_DEBUG not defined, include <sys/lock.h> before <sys/mutex.h>
 #endif
 #if LOCK_DEBUG > 0 || defined(MUTEX_NOINLINE)
-#define	mtx_lock_flags(m, opts)						\
-	_mtx_lock_flags((m), (opts), LOCK_FILE, LOCK_LINE)
-#define	mtx_unlock_flags(m, opts)					\
-	_mtx_unlock_flags((m), (opts), LOCK_FILE, LOCK_LINE)
-#define	mtx_lock_spin_flags(m, opts)					\
-	_mtx_lock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE)
-#define	mtx_unlock_spin_flags(m, opts)					\
-	_mtx_unlock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE)
+#define	mtx_lock_flags_(m, opts, file, line)				\
+	_mtx_lock_flags((m), (opts), (file), (line))
+#define	mtx_unlock_flags_(m, opts, file, line)				\
+	_mtx_unlock_flags((m), (opts), (file), (line))
+#define	mtx_lock_spin_flags_(m, opts, file, line)			\
+	_mtx_lock_spin_flags((m), (opts), (file), (line))
+#define	mtx_unlock_spin_flags_(m, opts, file, line)			\
+	_mtx_unlock_spin_flags((m), (opts), (file), (line))
 #else	/* LOCK_DEBUG == 0 && !MUTEX_NOINLINE */
+#define	mtx_lock_flags_(m, opts, file, line)				\
+	__mtx_lock((m), curthread, (opts), (file), (line))
+#define	mtx_unlock_flags_(m, opts, file, line)				\
+	__mtx_unlock((m), curthread, (opts), (file), (line))
+#define	mtx_lock_spin_flags_(m, opts, file, line)			\
+	__mtx_lock_spin((m), curthread, (opts), (file), (line))
+#define	mtx_unlock_spin_flags_(m, opts, file, line)			\
+	__mtx_unlock_spin((m))
+#endif	/* LOCK_DEBUG > 0 || MUTEX_NOINLINE */
+
+#ifdef INVARIANTS
+#define	mtx_assert_(m, what, file, line)				\
+	_mtx_assert((m), (what), (file), (line))
+
+#define GIANT_REQUIRED	mtx_assert_(&Giant, MA_OWNED, __FILE__, __LINE__)
+
+#else	/* INVARIANTS */
+#define mtx_assert_(m, what, file, line)	(void)0
+#define GIANT_REQUIRED
+#endif	/* INVARIANTS */
+
 #define	mtx_lock_flags(m, opts)						\
-	__mtx_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
+	mtx_lock_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
 #define	mtx_unlock_flags(m, opts)					\
-	__mtx_unlock((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
+	mtx_unlock_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
 #define	mtx_lock_spin_flags(m, opts)					\
-	__mtx_lock_spin((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
+	mtx_lock_spin_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
 #define	mtx_unlock_spin_flags(m, opts)					\
-	__mtx_unlock_spin((m))
-#endif	/* LOCK_DEBUG > 0 || MUTEX_NOINLINE */
-
+	mtx_unlock_spin_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
 #define mtx_trylock_flags(m, opts)					\
-	_mtx_trylock((m), (opts), LOCK_FILE, LOCK_LINE)
+	mtx_trylock_flags_((m), (opts), LOCK_FILE, LOCK_LINE)
+#define	mtx_assert(m, what)						\
+	mtx_assert_((m), (what), __FILE__, __LINE__)
 
 #define	mtx_sleep(chan, mtx, pri, wmesg, timo)				\
 	_sleep((chan), &(mtx)->lock_object, (pri), (wmesg), (timo))
@@ -398,17 +424,6 @@ struct mtx_args {
 #define MA_NOTRECURSED	LA_NOTRECURSED
 #endif
 
-#ifdef INVARIANTS
-#define	mtx_assert(m, what)						\
-	_mtx_assert((m), (what), __FILE__, __LINE__)
-
-#define GIANT_REQUIRED	mtx_assert(&Giant, MA_OWNED)
-
-#else	/* INVARIANTS */
-#define mtx_assert(m, what)	(void)0
-#define GIANT_REQUIRED
-#endif	/* INVARIANTS */
-
 /*
  * Common lock type names.
  */