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 <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Matt Macy <[email protected]>
Closes #10843

1 files changed, 44 insertions, 0 deletions

diff --git a/module/os/linux/spl/spl-condvar.c b/module/os/linux/spl/spl-condvar.c
index 9d045e3e8..49f486645 100644
--- a/module/os/linux/spl/spl-condvar.c
+++ b/module/os/linux/spl/spl-condvar.c
@@ -198,6 +198,18 @@ __cv_wait_sig(kcondvar_t *cvp, kmutex_t *mp)
 }
 EXPORT_SYMBOL(__cv_wait_sig);
 
+void
+__cv_wait_idle(kcondvar_t *cvp, kmutex_t *mp)
+{
+	sigset_t blocked, saved;
+
+	sigfillset(&blocked);
+	(void) sigprocmask(SIG_BLOCK, &blocked, &saved);
+	cv_wait_common(cvp, mp, TASK_INTERRUPTIBLE, 0);
+	(void) sigprocmask(SIG_SETMASK, &saved, NULL);
+}
+EXPORT_SYMBOL(__cv_wait_idle);
+
 #if defined(HAVE_IO_SCHEDULE_TIMEOUT)
 #define	spl_io_schedule_timeout(t)	io_schedule_timeout(t)
 #else
@@ -330,6 +342,21 @@ __cv_timedwait_sig(kcondvar_t *cvp, kmutex_t *mp, clock_t exp_time)
 }
 EXPORT_SYMBOL(__cv_timedwait_sig);
 
+int
+__cv_timedwait_idle(kcondvar_t *cvp, kmutex_t *mp, clock_t exp_time)
+{
+	sigset_t blocked, saved;
+	int rc;
+
+	sigfillset(&blocked);
+	(void) sigprocmask(SIG_BLOCK, &blocked, &saved);
+	rc = __cv_timedwait_common(cvp, mp, exp_time,
+	    TASK_INTERRUPTIBLE, 0);
+	(void) sigprocmask(SIG_SETMASK, &saved, NULL);
+
+	return (rc);
+}
+EXPORT_SYMBOL(__cv_timedwait_idle);
 /*
  * 'expire_time' argument is an absolute clock time in nanoseconds.
  * Return value is time left (expire_time - now) or -1 if timeout occurred.
@@ -427,6 +454,23 @@ cv_timedwait_sig_hires(kcondvar_t *cvp, kmutex_t *mp, hrtime_t tim,
 }
 EXPORT_SYMBOL(cv_timedwait_sig_hires);
 
+int
+cv_timedwait_idle_hires(kcondvar_t *cvp, kmutex_t *mp, hrtime_t tim,
+    hrtime_t res, int flag)
+{
+	sigset_t blocked, saved;
+	int rc;
+
+	sigfillset(&blocked);
+	(void) sigprocmask(SIG_BLOCK, &blocked, &saved);
+	rc = cv_timedwait_hires_common(cvp, mp, tim, res, flag,
+	    TASK_INTERRUPTIBLE);
+	(void) sigprocmask(SIG_SETMASK, &saved, NULL);
+
+	return (rc);
+}
+EXPORT_SYMBOL(cv_timedwait_idle_hires);
+
 void
 __cv_signal(kcondvar_t *cvp)
 {