mod.h: make consistent across all three platforms

mod.h only exists to include the platform-specific mod_os.h, so we can
get rid of it and just call the platform header mod.h.

Then, create a libspl mod.h, and move the relevant items to it so we can
start building on it.

Sponsored-by: https://despairlabs.com/sponsor/
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Closes #17537

include/Makefile.am

@@ -69,7 +69,6 @@ COMMON_H = \
 	sys/metaslab_impl.h \
 	sys/mmp.h \
 	sys/mntent.h \
-	sys/mod.h \
 	sys/multilist.h \
 	sys/nvpair.h \
 	sys/nvpair_impl.h \

include/os/freebsd/Makefile.am

@@ -33,7 +33,7 @@ noinst_HEADERS = \
 	%D%/spl/sys/list_impl.h \
 	%D%/spl/sys/lock.h \
 	%D%/spl/sys/misc.h \
-	%D%/spl/sys/mod_os.h \
+	%D%/spl/sys/mod.h \
 	%D%/spl/sys/mode.h \
 	%D%/spl/sys/mount.h \
 	%D%/spl/sys/mutex.h \

include/os/linux/Makefile.am

@@ -75,7 +75,7 @@ kernel_spl_sys_HEADERS = \
 	%D%/spl/sys/kstat.h \
 	%D%/spl/sys/list.h \
 	%D%/spl/sys/misc.h \
-	%D%/spl/sys/mod_os.h \
+	%D%/spl/sys/mod.h \
 	%D%/spl/sys/mutex.h \
 	%D%/spl/sys/param.h \
 	%D%/spl/sys/proc.h \

include/sys/mod.h

@@ -1,36 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
- *  Copyright (C) 2007 The Regents of the University of California.
- *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
- *  Written by Brian Behlendorf <behlendorf1@llnl.gov>.
- *  UCRL-CODE-235197
- *
- *  This file is part of the SPL, Solaris Porting Layer.
- *
- *  The SPL is free software; you can redistribute it and/or modify it
- *  under the terms of the GNU General Public License as published by the
- *  Free Software Foundation; either version 2 of the License, or (at your
- *  option) any later version.
- *
- *  The SPL is distributed in the hope that it will be useful, but WITHOUT
- *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- *  for more details.
- *
- *  You should have received a copy of the GNU General Public License along
- *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
- */
-#ifndef _SYS_MOD_H
-#define	_SYS_MOD_H
-
-#ifdef _KERNEL
-#include <sys/mod_os.h>
-#else
-/*
- * Exported symbols
- */
-#define	EXPORT_SYMBOL(x)
-#endif
-
-#endif /* SYS_MOD_H */

include/sys/vdev_impl.h

@@ -645,7 +645,7 @@ extern int vdev_obsolete_counts_are_precise(vdev_t *vd, boolean_t *are_precise);
 int vdev_checkpoint_sm_object(vdev_t *vd, uint64_t *sm_obj);
 void vdev_metaslab_group_create(vdev_t *vd);
 uint64_t vdev_best_ashift(uint64_t logical, uint64_t a, uint64_t b);
-#if defined(__linux__)
+#if defined(__linux__) && defined(_KERNEL)
 int param_get_raidz_impl(char *buf, zfs_kernel_param_t *kp);
 #endif
 int param_set_raidz_impl(ZFS_MODULE_PARAM_ARGS);

include/sys/zfs_context.h

@@ -204,18 +204,6 @@ extern void vpanic(const char *, va_list)
 #endif	/* DTRACE_PROBE4 */
 #define	DTRACE_PROBE4(a, b, c, d, e, f, g, h, i)
 
-/*
- * Tunables.
- */
-typedef struct zfs_kernel_param {
-	const char *name;	/* unused stub */
-} zfs_kernel_param_t;
-
-#define	ZFS_MODULE_PARAM(scope_prefix, name_prefix, name, type, perm, desc)
-#define	ZFS_MODULE_PARAM_ARGS void
-#define	ZFS_MODULE_PARAM_CALL(scope_prefix, name_prefix, name, setfunc, \
-	getfunc, perm, desc)
-
 /*
  * Threads.
  */