Condition variable usage, zevent_cv

The following incorrect usage of cv_broadcast() was caught by
code inspection.  The cv_broadcast() function must be called
under the associated mutex to preventing racing with cv_wait().

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>

diff --git a/module/zfs/fm.c b/module/zfs/fm.c
index ce0ebe0..c004032 100644 (file)
--- a/module/zfs/fm.c
+++ b/module/zfs/fm.c
@@ -481,14 +481,13 @@ zfs_zevent_drain_all(int *count)
 static void
 zfs_zevent_insert(zevent_t *ev)
 {
-       mutex_enter(&zevent_lock);
+       ASSERT(MUTEX_HELD(&zevent_lock));
        list_insert_head(&zevent_list, ev);
+
        if (zevent_len_cur >= zfs_zevent_len_max)
                zfs_zevent_drain(list_tail(&zevent_list));
        else
                zevent_len_cur++;
-
-       mutex_exit(&zevent_lock);
 }
 
 /*
@@ -528,8 +527,11 @@ zfs_zevent_post(nvlist_t *nvl, nvlist_t *detector, zevent_cb_t *cb)
         ev->ev_nvl = nvl;
        ev->ev_detector = detector;
        ev->ev_cb = cb;
+
+       mutex_enter(&zevent_lock);
        zfs_zevent_insert(ev);
        cv_broadcast(&zevent_cv);
+       mutex_exit(&zevent_lock);
 }
 
 static int
@@ -1520,9 +1522,10 @@ fm_fini(void)
        int count;
 
        zfs_zevent_drain_all(&count);
-       cv_broadcast(&zevent_cv);
 
        mutex_enter(&zevent_lock);
+       cv_broadcast(&zevent_cv);
+
        zevent_flags |= ZEVENT_SHUTDOWN;
        while (zevent_waiters > 0) {
                mutex_exit(&zevent_lock);