Fix: support duplicate health type

Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>

diff --git a/src/bin/lttng-sessiond/health.c b/src/bin/lttng-sessiond/health.c
index b36ddc4a337b6bc6c5aa389d45c004a0c3be9580..dcf3b96e2b48c7fc4030005818d2bb92b4dda71a 100644 (file)
--- a/src/bin/lttng-sessiond/health.c
+++ b/src/bin/lttng-sessiond/health.c
@@ -107,51 +107,17 @@ static int time_diff_gt(const struct timespec *time_a,
 }
 
 /*
- * Health mutex MUST be held across use of the returned struct health_state to
- * provide existence guarantee.
- *
- * Return the health_state object or NULL if not found.
- */
-static struct health_state *find_health_state(enum health_type type)
-{
-       struct health_state *state;
-
-       /* Find the right health state in the global TLS list. */
-       cds_list_for_each_entry(state, &health_state_list.head, node) {
-               if (state->type == type) {
-                       return state;
-               }
-       }
-
-       return NULL;
-}
-
-/*
- * Check health of a specific health type. Note that if a thread has not yet
- * initialize its health subsystem or has quit, it's considered in a good
- * state.
+ * Validate health state. Checks for the error flag or health conditions.
  *
  * Return 0 if health is bad or else 1.
  */
-int health_check_state(enum health_type type)
+static int validate_state(struct health_state *state)
 {
        int retval = 1, ret;
        unsigned long current, last;
        struct timespec current_time;
-       struct health_state *state;
-
-       assert(type < HEALTH_NUM_TYPE);
-
-       state_lock();
 
-       state = find_health_state(type);
-       if (!state) {
-               /* Check the global state since the state is not visiable anymore. */
-               if (global_error_state[type] & HEALTH_ERROR) {
-                       retval = 0;
-               }
-               goto not_found;
-       }
+       assert(state);
 
        last = state->last;
        current = uatomic_read(&state->current);
@@ -192,15 +158,60 @@ int health_check_state(enum health_type type)
                        /* update last counter and last sample time */
                        state->last = current;
                        memcpy(&state->last_time, &current_time, sizeof(current_time));
+
+                       /* On error, stop right now and notify caller. */
+                       if (retval == 0) {
+                               goto end;
+                       }
                }
        }
 
 end:
        DBG("Health state current %lu, last %lu, ret %d",
                        current, last, ret);
-not_found:
+       return retval;
+}
+
+/*
+ * Check health of a specific health type. Note that if a thread has not yet
+ * initialize its health subsystem or has quit, it's considered in a good
+ * state.
+ *
+ * Return 0 if health is bad or else 1.
+ */
+int health_check_state(enum health_type type)
+{
+       int retval = 1;
+       struct health_state *state;
+
+       assert(type < HEALTH_NUM_TYPE);
+
+       state_lock();
+
+       cds_list_for_each_entry(state, &health_state_list.head, node) {
+               int ret;
+
+               if (state->type != type) {
+                       continue;
+               }
+
+               ret = validate_state(state);
+               if (!ret) {
+                       retval = 0;
+                       goto end;
+               }
+       }
+
+       /* Check the global state since some state might not be visible anymore. */
+       if (global_error_state[type] & HEALTH_ERROR) {
+               retval = 0;
+       }
+
+end:
        state_unlock();
 
+       DBG("Health check for type %d is %s", (int) type,
+                       (retval == 0) ? "BAD" : "GOOD");
        return retval;
 }
 
@@ -209,8 +220,6 @@ not_found:
  */
 void health_register(enum health_type type)
 {
-       struct health_state *state;
-
        assert(type < HEALTH_NUM_TYPE);
 
        /* Init TLS state. */
@@ -223,13 +232,6 @@ void health_register(enum health_type type)
 
        /* Add it to the global TLS state list. */
        state_lock();
-       state = find_health_state(type);
-       /*
-        * Duplicates are not accepted, since lookups don't handle them at the
-        * moment.
-        */
-       assert(!state);
-
        cds_list_add(&URCU_TLS(health_state).node, &health_state_list.head);
        state_unlock();
 }