Introduce no_poll() default method for device drivers. Have it

do exactly the same as vop_nopoll() for consistency and put a
comment in the two pointing at each other.

Retire seltrue() in favour of no_poll().

Create private default functions in kern_conf.c instead of public
ones.

Change default strategy to return the bio with ENODEV instead of
doing nothing which would lead the bio stranded.

Retire public nullopen() and nullclose() as well as the entire band
of public no{read,write,ioctl,mmap,kqfilter,strategy,poll,dump}
funtions, they are the default actions now.

Move the final two trivial functions from subr_xxx.c to kern_conf.c
and retire the now empty subr_xxx.c

8 files changed, 76 insertions, 236 deletions

diff --git a/sys/conf/files b/sys/conf/files
index b465e44..8adf4dc 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -1147,7 +1147,6 @@ kern/subr_smp.c		optional smp
 kern/subr_taskqueue.c	standard
 kern/subr_trap.c	standard
 kern/subr_witness.c	optional witness
-kern/subr_xxx.c		standard
 kern/sys_generic.c	standard
 kern/sys_pipe.c		standard
 kern/sys_process.c	standard
diff --git a/sys/kern/kern_conf.c b/sys/kern/kern_conf.c
index 56eaf11..d578077 100644
--- a/sys/kern/kern_conf.c
+++ b/sys/kern/kern_conf.c
@@ -39,6 +39,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/conf.h>
 #include <sys/vnode.h>
 #include <sys/queue.h>
+#include <sys/poll.h>
 #include <sys/ctype.h>
 #include <machine/stdarg.h>
 
@@ -68,7 +69,19 @@ static int ready_for_devs;
 static int free_devt;
 SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, "");
 
-/* Define a dead_cdevsw for use when devices leave unexpectedly. */
+int
+nullop(void)
+{
+
+	return (0);
+}
+
+int
+eopnotsupp(void)
+{
+
+	return (EOPNOTSUPP);
+}
 
 static int
 enxio(void)
@@ -76,13 +89,21 @@ enxio(void)
 	return (ENXIO);
 }
 
+static int
+enodev(void)
+{
+	return (ENODEV);
+}
+
+/* Define a dead_cdevsw for use when devices leave unexpectedly. */
+
 #define dead_open	(d_open_t *)enxio
 #define dead_close	(d_close_t *)enxio
 #define dead_read	(d_read_t *)enxio
 #define dead_write	(d_write_t *)enxio
 #define dead_ioctl	(d_ioctl_t *)enxio
-#define dead_poll	nopoll
-#define dead_mmap	nommap
+#define dead_poll	(d_poll_t *)enodev
+#define dead_mmap	(d_mmap_t *)enodev
 
 static void
 dead_strategy(struct bio *bp)
@@ -92,7 +113,6 @@ dead_strategy(struct bio *bp)
 }
 
 #define dead_dump	(dumper_t *)enxio
-
 #define dead_kqfilter	(d_kqfilter_t *)enxio
 
 static struct cdevsw dead_cdevsw = {
@@ -110,6 +130,47 @@ static struct cdevsw dead_cdevsw = {
 	.d_kqfilter =	dead_kqfilter
 };
 
+/* Default methods if driver does not specify method */
+
+#define null_open	(d_open_t *)nullop
+#define null_close	(d_close_t *)nullop
+#define no_read		(d_read_t *)enodev
+#define no_write	(d_write_t *)enodev
+#define no_ioctl	(d_ioctl_t *)enodev
+#define no_mmap		(d_mmap_t *)enodev
+
+static int
+no_kqfilter(dev_t dev __unused, struct knote *kn __unused)
+{
+
+	return (1);
+}
+
+static void
+no_strategy(struct bio *bp)
+{
+
+	biofinish(bp, NULL, ENODEV);
+}
+
+static int
+no_poll(dev_t dev __unused, int events, struct thread *td __unused)
+{
+	/*
+	 * Return true for read/write.  If the user asked for something
+	 * special, return POLLNVAL, so that clients have a way of
+	 * determining reliably whether or not the extended
+	 * functionality is present without hard-coding knowledge
+	 * of specific filesystem implementations.
+	 * Stay in sync with vop_nopoll().
+	 */
+	if (events & ~POLLSTANDARD)
+		return (POLLNVAL);
+
+	return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
+}
+
+#define no_dump		(dumper_t *)enodev
 
 struct cdevsw *
 devsw(dev_t dev)
@@ -276,16 +337,16 @@ make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, const
 	KASSERT((minor & ~0xffff00ff) == 0,
 	    ("Invalid minor (0x%x) in make_dev", minor));
 
-	if (devsw->d_open == NULL)	devsw->d_open = nullopen;
-	if (devsw->d_close == NULL)	devsw->d_close = nullclose;
-	if (devsw->d_read == NULL)	devsw->d_read = noread;
-	if (devsw->d_write == NULL)	devsw->d_write = nowrite;
-	if (devsw->d_ioctl == NULL)	devsw->d_ioctl = noioctl;
-	if (devsw->d_poll == NULL)	devsw->d_poll = nopoll;
-	if (devsw->d_mmap == NULL)	devsw->d_mmap = nommap;
-	if (devsw->d_strategy == NULL)	devsw->d_strategy = nostrategy;
-	if (devsw->d_dump == NULL)	devsw->d_dump = nodump;
-	if (devsw->d_kqfilter == NULL)	devsw->d_kqfilter = nokqfilter;
+	if (devsw->d_open == NULL)	devsw->d_open = null_open;
+	if (devsw->d_close == NULL)	devsw->d_close = null_close;
+	if (devsw->d_read == NULL)	devsw->d_read = no_read;
+	if (devsw->d_write == NULL)	devsw->d_write = no_write;
+	if (devsw->d_ioctl == NULL)	devsw->d_ioctl = no_ioctl;
+	if (devsw->d_poll == NULL)	devsw->d_poll = no_poll;
+	if (devsw->d_mmap == NULL)	devsw->d_mmap = no_mmap;
+	if (devsw->d_strategy == NULL)	devsw->d_strategy = no_strategy;
+	if (devsw->d_dump == NULL)	devsw->d_dump = no_dump;
+	if (devsw->d_kqfilter == NULL)	devsw->d_kqfilter = no_kqfilter;
 
 	if (devsw->d_maj == MAJOR_AUTO) {
 		for (i = NUMCDEVSW - 1; i > 0; i--)
diff --git a/sys/kern/subr_xxx.c b/sys/kern/subr_xxx.c
deleted file mode 100644
index 186cc0b..0000000
--- a/sys/kern/subr_xxx.c
+++ /dev/null
@@ -1,185 +0,0 @@
-/*
- * Copyright (c) 1982, 1986, 1991, 1993
- *	The Regents of the University of California.  All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- *    must display the following acknowledgement:
- *	This product includes software developed by the University of
- *	California, Berkeley and its contributors.
- * 4. Neither the name of the University nor the names of its contributors
- *    may be used to endorse or promote products derived from this software
- *    without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- *	@(#)subr_xxx.c	8.1 (Berkeley) 6/10/93
- */
-
-/*
- * Miscellaneous trivial functions.
- */
-
-#include <sys/cdefs.h>
-__FBSDID("$FreeBSD$");
-
-#include <sys/param.h>
-#include <sys/systm.h>
-
-/*
- * Return error for operation not supported
- * on a specific object or file type.
- */
-int
-eopnotsupp()
-{
-
-	return (EOPNOTSUPP);
-}
-
-/*
- * Generic null operation, always returns success.
- */
-int
-nullop()
-{
-
-	return (0);
-}
-
-#include <sys/conf.h>
-
-/*
- * Unsupported devswitch functions (e.g. for writing to read-only device).
- * XXX may belong elsewhere.
- */
-
-int
-noopen(dev, flags, fmt, td)
-	dev_t dev;
-	int flags;
-	int fmt;
-	struct thread *td;
-{
-
-	return (ENODEV);
-}
-
-int
-noclose(dev, flags, fmt, td)
-	dev_t dev;
-	int flags;
-	int fmt;
-	struct thread *td;
-{
-
-	return (ENODEV);
-}
-
-int
-noread(dev, uio, ioflag)
-	dev_t dev;
-	struct uio *uio;
-	int ioflag;
-{
-
-	return (ENODEV);
-}
-
-int
-nowrite(dev, uio, ioflag)
-	dev_t dev;
-	struct uio *uio;
-	int ioflag;
-{
-
-	return (ENODEV);
-}
-
-int
-noioctl(dev, cmd, data, flags, td)
-	dev_t dev;
-	u_long cmd;
-	caddr_t data;
-	int flags;
-	struct thread *td;
-{
-
-	return (ENODEV);
-}
-
-int
-nokqfilter(dev, kn)
-	dev_t dev;
-	struct knote *kn;
-{
-
-	return (1);
-}
-
-int
-nommap(dev, offset, paddr, nprot)
-	dev_t dev;
-	vm_offset_t offset;
-	vm_paddr_t *paddr;
-	int nprot;
-{
-
-	return (ENODEV);
-}
-
-int
-nodump(void *arg, void *virtual __unused, vm_offset_t physical __unused, off_t offset __unused, size_t length __unused)
-{
-
-	return (ENODEV);
-}
-
-/*
- * Null devswitch functions (for when the operation always succeeds).
- * XXX may belong elsewhere.
- * XXX not all are here (e.g., seltrue() isn't).
- */
-
-/*
- * XXX this is probably bogus.  Any device that uses it isn't checking the
- * minor number.
- */
-int
-nullopen(dev, flags, fmt, td)
-	dev_t dev;
-	int flags;
-	int fmt;
-	struct thread *td;
-{
-
-	return (0);
-}
-
-int
-nullclose(dev, flags, fmt, td)
-	dev_t dev;
-	int flags;
-	int fmt;
-	struct thread *td;
-{
-
-	return (0);
-}
diff --git a/sys/kern/sys_generic.c b/sys/kern/sys_generic.c
index eec9c76..221ec00 100644
--- a/sys/kern/sys_generic.c
+++ b/sys/kern/sys_generic.c
@@ -1132,17 +1132,6 @@ clear_selinfo_list(td)
 	TAILQ_INIT(&td->td_selq);
 }
 
-/*ARGSUSED*/
-int
-seltrue(dev, events, td)
-	dev_t dev;
-	int events;
-	struct thread *td;
-{
-
-	return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
-}
-
 /*
  * Record a select request.
  */
diff --git a/sys/kern/vfs_default.c b/sys/kern/vfs_default.c
index 7626228..41c4040 100644
--- a/sys/kern/vfs_default.c
+++ b/sys/kern/vfs_default.c
@@ -343,6 +343,7 @@ vop_nopoll(ap)
 	 * determining reliably whether or not the extended
 	 * functionality is present without hard-coding knowledge
 	 * of specific filesystem implementations.
+	 * Stay in sync with kern_conf.c::no_poll().
 	 */
 	if (ap->a_events & ~POLLSTANDARD)
 		return (POLLNVAL);
diff --git a/sys/sys/conf.h b/sys/sys/conf.h
index 14facba..c18d5b4 100644
--- a/sys/sys/conf.h
+++ b/sys/sys/conf.h
@@ -258,23 +258,11 @@ void ldisc_deregister(int);
 #endif /* _KERNEL */
 
 #ifdef _KERNEL
-d_read_t	noread;
-d_write_t	nowrite;
-d_ioctl_t	noioctl;
-d_mmap_t	nommap;
-d_kqfilter_t	nokqfilter;
-#define	nostrategy	((d_strategy_t *)NULL)
-#define	nopoll	seltrue
-
-dumper_t	nodump;
 
 #define NUMCDEVSW 256
 
 #define	MAJOR_AUTO	0	/* XXX: Not GM */
 
-d_open_t	nullopen;
-d_close_t	nullclose;
-
 l_ioctl_t	l_nullioctl;
 l_read_t	l_noread;
 l_write_t	l_nowrite;
diff --git a/sys/sys/linedisc.h b/sys/sys/linedisc.h
index 14facba..c18d5b4 100644
--- a/sys/sys/linedisc.h
+++ b/sys/sys/linedisc.h
@@ -258,23 +258,11 @@ void ldisc_deregister(int);
 #endif /* _KERNEL */
 
 #ifdef _KERNEL
-d_read_t	noread;
-d_write_t	nowrite;
-d_ioctl_t	noioctl;
-d_mmap_t	nommap;
-d_kqfilter_t	nokqfilter;
-#define	nostrategy	((d_strategy_t *)NULL)
-#define	nopoll	seltrue
-
-dumper_t	nodump;
 
 #define NUMCDEVSW 256
 
 #define	MAJOR_AUTO	0	/* XXX: Not GM */
 
-d_open_t	nullopen;
-d_close_t	nullclose;
-
 l_ioctl_t	l_nullioctl;
 l_read_t	l_noread;
 l_write_t	l_nowrite;
diff --git a/sys/sys/systm.h b/sys/sys/systm.h
index e3e8dc4..bd034ea 100644
--- a/sys/sys/systm.h
+++ b/sys/sys/systm.h
@@ -126,7 +126,6 @@ void	Debugger(const char *msg) __nonnull(1);
 int	dumpstatus(vm_offset_t addr, off_t count);
 int	nullop(void);
 int	eopnotsupp(void);
-int	seltrue(dev_t dev, int which, struct thread *td);
 int	ureadc(int, struct uio *);
 void	hashdestroy(void *, struct malloc_type *, u_long);
 void	*hashinit(int count, struct malloc_type *type, u_long *hashmask);