SUNRPC: change svc_pool::sp_flags bits to enum

When a sequence of numbers are needed for internal-use only, an enum is
typically best.  The sequence will inevitably need to be changed one
day, and having an enum means the developer doesn't need to think about
renumbering after insertion or deletion.  Such patches will be easier
to review.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

include/linux/sunrpc/svc.h

@@ -42,12 +42,16 @@ struct svc_pool {
 	struct percpu_counter	sp_sockets_queued;
 	struct percpu_counter	sp_threads_woken;
 
-#define	SP_TASK_PENDING		(0)		/* still work to do even if no
-						 * xprt is queued. */
-#define SP_CONGESTED		(1)
 	unsigned long		sp_flags;
 } ____cacheline_aligned_in_smp;
 
+/* bits for sp_flags */
+enum {
+	SP_TASK_PENDING,	/* still work to do even if no xprt is queued */
+	SP_CONGESTED,		/* all threads are busy, none idle */
+};
+
+
 /*
  * RPC service.
  *