Factor Linux specific code out of spa_misc.c

Move these Linux module parameter get/set helpers in to
platform specific code.

Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes #9457

include/os/linux/kernel/linux/mod_compat.h

@@ -53,6 +53,7 @@ enum scope_prefix_types {
 	zfs_condense,
 	zfs_dbuf,
 	zfs_dbuf_cache,
+	zfs_deadman,
 	zfs_l2arc,
 	zfs_livelist,
 	zfs_livelist_condense,
@@ -71,6 +72,7 @@ enum scope_prefix_types {
 	zfs_vdev_mirror,
 	zfs_zio,
 	zfs_zil,
+	spa
 };
 
 /*

include/sys/spa.h

@@ -1171,6 +1171,11 @@ extern int spa_wait_tag(const char *name, zpool_wait_activity_t activity,
 extern void spa_notify_waiters(spa_t *spa);
 extern void spa_wake_waiters(spa_t *spa);
 
+/* module param call functions */
+int param_set_deadman_ziotime(const char *val, zfs_kernel_param_t *kp);
+int param_set_deadman_synctime(const char *val, zfs_kernel_param_t *kp);
+int param_set_slop_shift(const char *buf, zfs_kernel_param_t *kp);
+
 #ifdef ZFS_DEBUG
 #define	dprintf_bp(bp, fmt, ...) do {				\
 	if (zfs_flags & ZFS_DEBUG_DPRINTF) {			\

include/sys/spa_impl.h

@@ -433,7 +433,7 @@ struct spa {
 };
 
 extern char *spa_config_path;
-
+extern int spa_slop_shift;
 extern void spa_taskq_dispatch_ent(spa_t *spa, zio_type_t t, zio_taskq_type_t q,
     task_func_t *func, void *arg, uint_t flags, taskq_ent_t *ent);
 extern void spa_taskq_dispatch_sync(spa_t *, zio_type_t t, zio_taskq_type_t q,