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: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This commit is contained in:
NeilBrown 2023-09-11 10:40:15 -04:00 committed by Chuck Lever
parent 2e8fc923fe
commit 580a25756a
2 changed files with 5 additions and 6 deletions

View file

@ -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 */

View file

@ -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);