thread: add spdk_thread_has_pollers()

This function add possibility to check if there are registered pollers
on particular thread.

Change-Id: I80af06a10c5c1b54fed5bb28a3aa769a52d8a206
Signed-off-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-on: https://review.gerrithub.io/c/446624
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>

CHANGELOG.md

@@ -12,6 +12,11 @@ spdk_nvme_probe_poll_async() were added to enable this feature.
 Added new strip_size_kb rpc param on create to replace the more ambiguous
 strip_size. The strip_size rpc param is deprecated.
 
+### thread
+
+Added spdk_thread_has_pollers() function to verify if there are
+any registered pollers to be run on the thread.
+
 ## v19.01:
 
 ### ocf bdev

include/spdk/thread.h

@@ -267,6 +267,16 @@ uint64_t spdk_thread_next_poller_expiration(struct spdk_thread *thread);
  */
 int spdk_thread_has_active_pollers(struct spdk_thread *thread);
 
+/**
+ * Returns whether there are any pollers registered to be run
+ * on the thread.
+ *
+ * \param thread The thread to check.
+ *
+ * \return true if there is any active poller, false otherwise.
+ */
+bool spdk_thread_has_pollers(struct spdk_thread *thread);
+
 /**
  * Get count of allocated threads.
  */

lib/thread/thread.c

@@ -549,6 +549,17 @@ spdk_thread_has_active_pollers(struct spdk_thread *thread)
 	return !TAILQ_EMPTY(&thread->active_pollers);
 }
 
+bool
+spdk_thread_has_pollers(struct spdk_thread *thread)
+{
+	if (TAILQ_EMPTY(&thread->active_pollers) &&
+	    TAILQ_EMPTY(&thread->timer_pollers)) {
+		return false;
+	}
+
+	return true;
+}
+
 uint32_t
 spdk_thread_get_count(void)
 {