SUNRPC: discard SP_CONGESTED

We can tell if a pool is congested by checking if the idle list is
empty.  We don't need a separate flag.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

include/linux/sunrpc/svc.h

@@ -50,7 +50,6 @@ struct svc_pool {
 /* 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 */
 	SP_NEED_VICTIM,		/* One thread needs to agree to exit */
 	SP_VICTIM_REMAINS,	/* One thread needs to actually exit */
 };

net/sunrpc/svc.c

@@ -719,7 +719,6 @@ void svc_pool_wake_idle_thread(struct svc_pool *pool)
 	}
 	rcu_read_unlock();
 
-	set_bit(SP_CONGESTED, &pool->sp_flags);
 }
 EXPORT_SYMBOL_GPL(svc_pool_wake_idle_thread);
 

net/sunrpc/svc_xprt.c

@@ -735,8 +735,6 @@ static void svc_rqst_wait_for_work(struct svc_rqst *rqstp)
 
 	if (rqst_should_sleep(rqstp)) {
 		set_current_state(TASK_IDLE);
-		smp_mb__before_atomic();
-		clear_bit(SP_CONGESTED, &pool->sp_flags);
 		spin_lock_bh(&pool->sp_lock);
 		list_add(&rqstp->rq_idle, &pool->sp_idle_threads);
 		spin_unlock_bh(&pool->sp_lock);
@@ -874,7 +872,7 @@ void svc_recv(struct svc_rqst *rqstp)
 		/* Normally we will wait up to 5 seconds for any required
 		 * cache information to be provided.
 		 */
-		if (!test_bit(SP_CONGESTED, &pool->sp_flags))
+		if (!list_empty(&pool->sp_idle_threads))
 			rqstp->rq_chandle.thread_wait = 5 * HZ;
 		else
 			rqstp->rq_chandle.thread_wait = 1 * HZ;