Commit 580a2575 authored by NeilBrown's avatar NeilBrown Committed by Chuck Lever
Browse files

SUNRPC: discard sp_lock 



sp_lock is now only used to protect sp_all_threads.  This isn't needed
as sp_all_threads is only manipulated through svc_set_num_threads(),
which is already serialized.  Read-acccess only requires rcu_read_lock().
So no more locking is needed.

Signed-off-by: default avatarNeilBrown <neilb@suse.de>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent 2e8fc923

include/linux/sunrpc/svc.h

+0 −1
Original line number Diff line number Diff line
@@ -34,7 +34,6 @@ 
 */

struct svc_pool {

	unsigned int		sp_id;	    	/* pool id; also node id on NUMA */

	spinlock_t		sp_lock;	/* protects all fields */

	struct lwq		sp_xprts;	/* pending transports */

	atomic_t		sp_nrthreads;	/* # of threads in pool */

	struct list_head	sp_all_threads;	/* all server threads */

net/sunrpc/svc.c

+5 −5
Original line number Diff line number Diff line
@@ -511,7 +511,6 @@ __svc_create(struct svc_program *prog, unsigned int bufsize, int npools, 
		lwq_init(&pool->sp_xprts);

		INIT_LIST_HEAD(&pool->sp_all_threads);

		init_llist_head(&pool->sp_idle_threads);

		spin_lock_init(&pool->sp_lock);



		percpu_counter_init(&pool->sp_messages_arrived, 0, GFP_KERNEL);

		percpu_counter_init(&pool->sp_sockets_queued, 0, GFP_KERNEL);
@@ -682,9 +681,12 @@ svc_prepare_thread(struct svc_serv *serv, struct svc_pool *pool, int node) 
	spin_unlock_bh(&serv->sv_lock);



	atomic_inc(&pool->sp_nrthreads);

	spin_lock_bh(&pool->sp_lock);



	/* Protected by whatever lock the service uses when calling

	 * svc_set_num_threads()

	 */

	list_add_rcu(&rqstp->rq_all, &pool->sp_all_threads);

	spin_unlock_bh(&pool->sp_lock);



	return rqstp;

}
@@ -922,9 +924,7 @@ svc_exit_thread(struct svc_rqst *rqstp) 
	struct svc_serv	*serv = rqstp->rq_server;

	struct svc_pool	*pool = rqstp->rq_pool;



	spin_lock_bh(&pool->sp_lock);

	list_del_rcu(&rqstp->rq_all);

	spin_unlock_bh(&pool->sp_lock);



	atomic_dec(&pool->sp_nrthreads);