sunrpc: convert sp_task_pending flag to use atomic bitops

In a later patch, we'll want to be able to handle this flag without
holding the sp_lock. Change this field to an unsigned long flags
field, and declare a new flag in it that can be managed with atomic
bitops.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 8054a30..5f0ab39 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -50,7 +50,9 @@
 	unsigned int		sp_nrthreads;	/* # of threads in pool */
 	struct list_head	sp_all_threads;	/* all server threads */
 	struct svc_pool_stats	sp_stats;	/* statistics on pool operation */
-	int			sp_task_pending;/* has pending task */
+#define	SP_TASK_PENDING		(0)		/* still work to do even if no
+						 * xprt is queued. */
+	unsigned long		sp_flags;
 } ____cacheline_aligned_in_smp;
 
 /*