Revert "loop: don't call the hooks around blocking wait"

This reverts commit 09fafdfc01.

spa/include/spa/support/loop.h

@@ -109,11 +109,8 @@ struct spa_loop_methods {
 	 *             an object that has identity.
 	 * \param size The size of data to copy.
 	 * \param block If \true, do not return until func has been called. Otherwise,
-	 *              returns immediately. Passing \true can cause a deadlock when
-	 *              the calling thread is holding the loop context lock. A blocking
-	 *              invoke should never be done from a realtime thread. Also beware
-	 *              of blocking invokes between 2 threads as you can easily end up
-	 *              in a deadly embrace.
+	 *              returns immediately. Passing \true does not risk a deadlock because
+	 *              the data thread is never allowed to wait on any other thread.
 	 * \param user_data An opaque pointer passed to func.
 	 * \return `-EPIPE` if the internal ring buffer filled up,
 	 *         if block is \false, 0 if seq was SPA_ID_INVALID or

spa/plugins/support/loop.c

@@ -365,10 +365,14 @@ retry:
 		if (block && queue->ack_fd != -1) {
 			uint64_t count = 1;
 
+			spa_loop_control_hook_before(&impl->hooks_list);
+
 			if ((res = spa_system_eventfd_read(impl->system, queue->ack_fd, &count)) < 0)
 				spa_log_warn(impl->log, "%p: failed to read event fd:%d: %s",
 						queue, queue->ack_fd, spa_strerror(res));
 
+			spa_loop_control_hook_after(&impl->hooks_list);
+
 			res = item->res;
 		}
 		else {