Make the rmlock(9) interface a bit more like the rwlock(9) interface:

- Add rm_init_flags() and accept extended options only for that variation.
- Add a flags space specifically for rm_init_flags(), rather than borrowing
  the lock_init() flag space.
- Define flag RM_RECURSE to use instead of LO_RECURSABLE.
- Define flag RM_NOWITNESS to allow an rmlock to be exempt from WITNESS
  checking; this wasn't possible previously as rm_init() always passed
  LO_WITNESS when initializing an rmlock's struct lock.
- Add RM_SYSINIT_FLAGS().
- Rename embedded mutex in rmlocks to make it more obvious what it is.
- Update consumers.
- Update man page.

share/man/man9/rmlock.9

@@ -32,6 +32,7 @@
 .Sh NAME
 .Nm rmlock ,
 .Nm rm_init ,
+.Nm rm_init_flags ,
 .Nm rm_destroy ,
 .Nm rm_rlock ,
 .Nm rm_wlock ,
@@ -45,7 +46,9 @@
 .In sys/lock.h
 .In sys/rmlock.h
 .Ft void
-.Fn rm_init "struct rmlock *rm" "const char *name" "int opts"
+.Fn rm_init "struct rmlock *rm" "const char *name"
+.Ft void
+.Fn rm_init_flags "struct rmlock *rm" "const char *name" "int opts"
 .Ft void
 .Fn rm_destroy "struct rmlock *rm"
 .Ft void
@@ -106,18 +109,33 @@ can recurse if the lock has been initialized with the
 option, however exclusive locks are not allowed to recurse.
 .Ss Macros and Functions
 .Bl -tag -width indent
-.It Fn rm_init "struct rmlock *rm" "const char *name" "int opts"
+.It Fn rm_init "struct rmlock *rm" "const char *name"
 Initialize structure located at
 .Fa rm
 as mostly reader lock, described by
 .Fa name .
-Optionally allowing readers to recurse by setting
-.Dv LO_RECURSABLE
-in
-.Fa opts .
 The name description is used solely for debugging purposes.
 This function must be called before any other operations
 on the lock.
+.It Fn rm_init_flags "struct rmlock *rm" "const char *name" "int opts"
+Initialize the rm lock just like the
+.Fn rm_init
+function, but specifying a set of optional flags to alter the
+behaviour of
+.Fa rm ,
+through the
+.Fa opts
+argument.
+It contains one or more of the following flags:
+.Bl -tag -width ".Dv RM_NOWITNESS"
+.It Dv RM_NOWITNESS
+Instruct
+.Xr witness 4
+to ignore this lock.
+.It Dv RM_RECURSE
+Allow threads to recursively acquire exclusive locks for
+.Fa rm .
+.El
 .It Fn rm_rlock "struct rmlock *rm" "struct rm_priotracker* tracker"
 Lock
 .Fa rm

sys/kern/kern_osd.c

@@ -394,7 +394,7 @@ osd_init(void *arg __unused)
 		osd_nslots[i] = 0;
 		LIST_INIT(&osd_list[i]);
 		sx_init(&osd_module_lock[i], "osd_module");
-		rm_init(&osd_object_lock[i], "osd_object", 0);
+		rm_init(&osd_object_lock[i], "osd_object");
 		mtx_init(&osd_list_lock[i], "osd_list", NULL, MTX_DEF);
 		osd_destructors[i] = NULL;
 		osd_methods[i] = NULL;

sys/kern/kern_rmlock.c

@@ -188,14 +188,26 @@ rm_cleanIPI(void *arg)
 }
 
 void
-rm_init(struct rmlock *rm, const char *name, int opts)
+rm_init_flags(struct rmlock *rm, const char *name, int opts)
 {
+	int liflags;
 
+	liflags = 0;
+	if (!(opts & RM_NOWITNESS))
+		liflags |= LO_WITNESS;
+	if (opts & RM_RECURSE)
+		liflags |= LO_RECURSABLE;
 	rm->rm_noreadtoken = 1;
 	LIST_INIT(&rm->rm_activeReaders);
-	mtx_init(&rm->rm_lock, name, "RM_MTX",MTX_NOWITNESS);
-	lock_init(&rm->lock_object, &lock_class_rm, name, NULL,
-	    (opts & LO_RECURSABLE)| LO_WITNESS);
+	mtx_init(&rm->rm_lock, name, "rmlock_mtx", MTX_NOWITNESS);
+	lock_init(&rm->lock_object, &lock_class_rm, name, NULL, liflags);
+}
+
+void
+rm_init(struct rmlock *rm, const char *name)
+{
+
+	rm_init_flags(rm, name, 0);
 }
 
 void
@@ -216,9 +228,17 @@ rm_wowned(struct rmlock *rm)
 void
 rm_sysinit(void *arg)
 {
-
 	struct rm_args *args = arg;
-	rm_init(args->ra_rm, args->ra_desc, args->ra_opts);
+
+	rm_init(args->ra_rm, args->ra_desc);
+}
+
+void
+rm_sysinit_flags(void *arg)
+{
+	struct rm_args_flags *args = arg;
+
+	rm_init_flags(args->ra_rm, args->ra_desc, args->ra_opts);
 }
 
 static void

sys/net/pfil.h

@@ -95,7 +95,7 @@ struct pfil_head *pfil_head_get(int, u_long);
 
 #define	PFIL_HOOKED(p) ((p)->ph_nhooks > 0)
 #define	PFIL_LOCK_INIT(p) \
-    rm_init(&(p)->ph_lock, "PFil hook read/write mutex", LO_RECURSABLE)
+    rm_init_flags(&(p)->ph_lock, "PFil hook read/write mutex", RM_RECURSE)
 #define	PFIL_LOCK_DESTROY(p) rm_destroy(&(p)->ph_lock)
 #define PFIL_RLOCK(p, t) rm_rlock(&(p)->ph_lock, (t))
 #define PFIL_WLOCK(p) rm_wlock(&(p)->ph_lock)

sys/security/mac/mac_framework.c

@@ -289,7 +289,7 @@ mac_init(void)
 	mac_labelzone_init();
 
 #ifndef MAC_STATIC
-	rm_init(&mac_policy_rm, "mac_policy_rm", 0);
+	rm_init(&mac_policy_rm, "mac_policy_rm");
 	sx_init(&mac_policy_sx, "mac_policy_sx");
 #endif
 }

sys/sys/rmlock.h

@@ -38,10 +38,18 @@
 
 #ifdef _KERNEL
 
-void	rm_init(struct rmlock *rm, const char *name, int opts);
+/*
+ * Flags passed to rm_init(9).
+ */
+#define	RM_NOWITNESS	0x00000001
+#define	RM_RECURSE	0x00000002
+
+void	rm_init(struct rmlock *rm, const char *name);
+void	rm_init_flags(struct rmlock *rm, const char *name, int opts);
 void	rm_destroy(struct rmlock *rm);
 int	rm_wowned(struct rmlock *rm);
 void	rm_sysinit(void *arg);
+void	rm_sysinit_flags(void *arg);
 
 void	_rm_wlock_debug(struct rmlock *rm, const char *file, int line);
 void	_rm_wunlock_debug(struct rmlock *rm, const char *file, int line);
@@ -79,19 +87,35 @@ void	_rm_runlock(struct rmlock *rm,  struct rm_priotracker *tracker);
 struct rm_args {
 	struct rmlock	*ra_rm;
 	const char 	*ra_desc;
+};
+
+struct rm_args_flags {
+	struct rmlock	*ra_rm;
+	const char 	*ra_desc;
 	int		ra_opts;
 };
 
-#define	RM_SYSINIT(name, rm, desc, opts)       				\
+#define	RM_SYSINIT(name, rm, desc)       				\
 	static struct rm_args name##_args = {				\
 		(rm),							\
 		(desc),							\
-                (opts),							\
 	};								\
 	SYSINIT(name##_rm_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE,	\
 	    rm_sysinit, &name##_args);					\
 	SYSUNINIT(name##_rm_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE,	\
 	    rm_destroy, (rm))
 
+
+#define	RM_SYSINIT_FLAGS(name, rm, desc, opts)       			\
+	static struct rm_args name##_args = {				\
+		(rm),							\
+		(desc),							\
+                (opts),							\
+	};								\
+	SYSINIT(name##_rm_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE,	\
+	    rm_sysinit_flags, &name##_args);				\
+	SYSUNINIT(name##_rm_sysuninit, SI_SUB_LOCK, SI_ORDER_MIDDLE,	\
+	    rm_destroy, (rm))
+
 #endif /* _KERNEL */
 #endif /* !_SYS_RMLOCK_H_ */