sys/bitset.h: reduce visibility of BIT_* macros

Add two underscore characters "__" to names of BIT_* and BITSET_*
macros to move them to the implementation name space and to prevent
a name space pollution due to BIT_* macros in 3rd party programs with
conflicting parameter signatures.

These prefixed macro names are used in kernel header files to define
macros in e.g. sched.h, sys/cpuset.h and sys/domainset.h.

If C programs are built with either -D_KERNEL (automatically passed
when building a kernel or kernel modules) or -D_WANT_FREENBSD_BITSET
(or this macros is defined in the source code before including the
bitset macros), then all macros are made visible with their previous
names, too. E.g., both __BIT_SET() and BIT_SET() are visible with
either of _KERNEL or _WANT_FREEBSD_BITSET defined.

The main reason for this change is that some 3rd party sources
including sched.h have been found to contain conflicting BIT_*
macros.

As a work-around, parts of shed.h have been made conditional and
depend on _WITH_CPU_SET_T being set when sched.h is included.
Ports that expect the full functionality provided by sched.h need
to be built with -D_WITH_CPU_SET_T. But this leads to conflicts if
BIT_* macros are defined in that program, too.

This patch set makes all of sched.h visible again without this
parameter being passed and without any name space pollution due
to BIT_* macros becoming visible when sched.h is included.

This patch set will be backported to the STABLE branches, but ports
will need to use -D_WITH_CPU_SET_T as long as there are supported
releases that do not contain these patches.

Reviewed by:	kib, markj
MFC after:	1 month
Relnotes:	yes
Differential Revision:	https://reviews.freebsd.org/D33235

freebsd/sbin/pfctl/pfctl_altq.c

@@ -31,6 +31,7 @@
 __FBSDID("$FreeBSD$");
 
 #define PFIOC_USE_LATEST
+#define _WANT_FREEBSD_BITSET
 
 #include <sys/types.h>
 #include <sys/bitset.h>

freebsd/sbin/pfctl/pfctl_parser.h

@@ -178,7 +178,7 @@ struct node_queue_opt {
 };
 
 #define QPRI_BITSET_SIZE	256
-BITSET_DEFINE(qpri_bitset, QPRI_BITSET_SIZE);
+__BITSET_DEFINE(qpri_bitset, QPRI_BITSET_SIZE);
 LIST_HEAD(gen_sc, segment);
 
 struct pfctl_altq {

freebsd/sys/sys/_domainset.h

@@ -43,7 +43,7 @@
 #define	DOMAINSET_SETSIZE	DOMAINSET_MAXSIZE
 #endif
 
-BITSET_DEFINE(_domainset, DOMAINSET_SETSIZE);
+__BITSET_DEFINE(_domainset, DOMAINSET_SETSIZE);
 typedef struct _domainset domainset_t;
 
 /*

freebsd/sys/sys/domainset.h

@@ -44,34 +44,34 @@
 	    sizeof(__XSTRING(MAXMEMDOM)))
 
 
-#define	DOMAINSET_CLR(n, p)		BIT_CLR(DOMAINSET_SETSIZE, n, p)
-#define	DOMAINSET_COPY(f, t)		BIT_COPY(DOMAINSET_SETSIZE, f, t)
-#define	DOMAINSET_ISSET(n, p)		BIT_ISSET(DOMAINSET_SETSIZE, n, p)
-#define	DOMAINSET_SET(n, p)		BIT_SET(DOMAINSET_SETSIZE, n, p)
-#define	DOMAINSET_ZERO(p) 		BIT_ZERO(DOMAINSET_SETSIZE, p)
-#define	DOMAINSET_FILL(p) 		BIT_FILL(DOMAINSET_SETSIZE, p)
-#define	DOMAINSET_SETOF(n, p)		BIT_SETOF(DOMAINSET_SETSIZE, n, p)
-#define	DOMAINSET_EMPTY(p)		BIT_EMPTY(DOMAINSET_SETSIZE, p)
-#define	DOMAINSET_ISFULLSET(p)		BIT_ISFULLSET(DOMAINSET_SETSIZE, p)
-#define	DOMAINSET_SUBSET(p, c)		BIT_SUBSET(DOMAINSET_SETSIZE, p, c)
-#define	DOMAINSET_OVERLAP(p, c)		BIT_OVERLAP(DOMAINSET_SETSIZE, p, c)
-#define	DOMAINSET_CMP(p, c)		BIT_CMP(DOMAINSET_SETSIZE, p, c)
-#define	DOMAINSET_OR(d, s)		BIT_OR(DOMAINSET_SETSIZE, d, s)
-#define	DOMAINSET_AND(d, s)		BIT_AND(DOMAINSET_SETSIZE, d, s)
-#define	DOMAINSET_NAND(d, s)		BIT_NAND(DOMAINSET_SETSIZE, d, s)
-#define	DOMAINSET_CLR_ATOMIC(n, p)	BIT_CLR_ATOMIC(DOMAINSET_SETSIZE, n, p)
-#define	DOMAINSET_SET_ATOMIC(n, p)	BIT_SET_ATOMIC(DOMAINSET_SETSIZE, n, p)
+#define	DOMAINSET_CLR(n, p)		__BIT_CLR(DOMAINSET_SETSIZE, n, p)
+#define	DOMAINSET_COPY(f, t)		__BIT_COPY(DOMAINSET_SETSIZE, f, t)
+#define	DOMAINSET_ISSET(n, p)		__BIT_ISSET(DOMAINSET_SETSIZE, n, p)
+#define	DOMAINSET_SET(n, p)		__BIT_SET(DOMAINSET_SETSIZE, n, p)
+#define	DOMAINSET_ZERO(p) 		__BIT_ZERO(DOMAINSET_SETSIZE, p)
+#define	DOMAINSET_FILL(p) 		__BIT_FILL(DOMAINSET_SETSIZE, p)
+#define	DOMAINSET_SETOF(n, p)		__BIT_SETOF(DOMAINSET_SETSIZE, n, p)
+#define	DOMAINSET_EMPTY(p)		__BIT_EMPTY(DOMAINSET_SETSIZE, p)
+#define	DOMAINSET_ISFULLSET(p)		__BIT_ISFULLSET(DOMAINSET_SETSIZE, p)
+#define	DOMAINSET_SUBSET(p, c)		__BIT_SUBSET(DOMAINSET_SETSIZE, p, c)
+#define	DOMAINSET_OVERLAP(p, c)		__BIT_OVERLAP(DOMAINSET_SETSIZE, p, c)
+#define	DOMAINSET_CMP(p, c)		__BIT_CMP(DOMAINSET_SETSIZE, p, c)
+#define	DOMAINSET_OR(d, s)		__BIT_OR(DOMAINSET_SETSIZE, d, s)
+#define	DOMAINSET_AND(d, s)		__BIT_AND(DOMAINSET_SETSIZE, d, s)
+#define	DOMAINSET_NAND(d, s)		__BIT_NAND(DOMAINSET_SETSIZE, d, s)
+#define	DOMAINSET_CLR_ATOMIC(n, p)	__BIT_CLR_ATOMIC(DOMAINSET_SETSIZE, n, p)
+#define	DOMAINSET_SET_ATOMIC(n, p)	__BIT_SET_ATOMIC(DOMAINSET_SETSIZE, n, p)
 #define	DOMAINSET_SET_ATOMIC_ACQ(n, p)					\
-	    BIT_SET_ATOMIC_ACQ(DOMAINSET_SETSIZE, n, p)
-#define	DOMAINSET_AND_ATOMIC(n, p)	BIT_AND_ATOMIC(DOMAINSET_SETSIZE, n, p)
-#define	DOMAINSET_OR_ATOMIC(d, s)	BIT_OR_ATOMIC(DOMAINSET_SETSIZE, d, s)
+	    __BIT_SET_ATOMIC_ACQ(DOMAINSET_SETSIZE, n, p)
+#define	DOMAINSET_AND_ATOMIC(n, p)	__BIT_AND_ATOMIC(DOMAINSET_SETSIZE, n, p)
+#define	DOMAINSET_OR_ATOMIC(d, s)	__BIT_OR_ATOMIC(DOMAINSET_SETSIZE, d, s)
 #define	DOMAINSET_COPY_STORE_REL(f, t)					\
-	    BIT_COPY_STORE_REL(DOMAINSET_SETSIZE, f, t)
-#define	DOMAINSET_FFS(p)		BIT_FFS(DOMAINSET_SETSIZE, p)
-#define	DOMAINSET_FLS(p)		BIT_FLS(DOMAINSET_SETSIZE, p)
-#define	DOMAINSET_COUNT(p)		BIT_COUNT(DOMAINSET_SETSIZE, p)
-#define	DOMAINSET_FSET			BITSET_FSET(_NDOMAINSETWORDS)
-#define	DOMAINSET_T_INITIALIZER		BITSET_T_INITIALIZER
+	    __BIT_COPY_STORE_REL(DOMAINSET_SETSIZE, f, t)
+#define	DOMAINSET_FFS(p)		__BIT_FFS(DOMAINSET_SETSIZE, p)
+#define	DOMAINSET_FLS(p)		__BIT_FLS(DOMAINSET_SETSIZE, p)
+#define	DOMAINSET_COUNT(p)		__BIT_COUNT(DOMAINSET_SETSIZE, p)
+#define	DOMAINSET_FSET			__BITSET_FSET(_NDOMAINSETWORDS)
+#define	DOMAINSET_T_INITIALIZER		__BITSET_T_INITIALIZER
 
 #define	DOMAINSET_POLICY_INVALID	0
 #define	DOMAINSET_POLICY_ROUNDROBIN	1