Replace cv_{timed}wait_sig with cv_{timed}wait_idle where appropriate

There are a number of places where cv_?_sig is used simply for
accounting purposes but the surrounding code has no ability to
cope with actually receiving a signal. On FreeBSD it is possible
to send signals to individual kernel threads so this could
enable undesirable behavior.

This patch adds routines on Linux that will do the same idle
accounting as _sig without making the task interruptible. On
FreeBSD cv_*_idle  are all aliases for cv_*

Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes #10843

include/os/freebsd/spl/sys/condvar.h

@@ -142,8 +142,14 @@ cv_timedwait_sig(kcondvar_t *cvp, kmutex_t *mp, clock_t timo)
 	return (1);
 }
 
-#define	cv_timedwait_io cv_timedwait
-#define	cv_timedwait_sig_io cv_timedwait_sig
+#define	cv_timedwait_io		cv_timedwait
+#define	cv_timedwait_idle	cv_timedwait
+#define	cv_timedwait_sig_io	cv_timedwait_sig
+#define	cv_wait_io		cv_wait
+#define	cv_wait_io_sig		cv_wait_sig
+#define	cv_wait_idle		cv_wait
+#define	cv_timedwait_io_hires	cv_timedwait_hires
+#define	cv_timedwait_idle_hires cv_timedwait_hires
 
 static inline int
 cv_timedwait_hires(kcondvar_t *cvp, kmutex_t *mp, hrtime_t tim, hrtime_t res,

include/os/freebsd/zfs/sys/zfs_context_os.h

@@ -41,9 +41,6 @@
 #include <sys/ccompat.h>
 #include <linux/types.h>
 
-#define	cv_wait_io(cv, mp)			cv_wait(cv, mp)
-#define	cv_wait_io_sig(cv, mp)			cv_wait_sig(cv, mp)
-
 #define	cond_resched()		kern_yield(PRI_USER)
 
 #define	taskq_create_sysdc(a, b, d, e, p, dc, f) \
@@ -84,7 +81,6 @@ typedef int fstrans_cookie_t;
 #define	signal_pending(x) SIGPENDING(x)
 #define	current curthread
 #define	thread_join(x)
-#define	cv_wait_io(cv, mp)			cv_wait(cv, mp)
 typedef struct opensolaris_utsname	utsname_t;
 extern utsname_t *utsname(void);
 extern int spa_import_rootpool(const char *name, bool checkpointrewind);