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Diffstat (limited to 'net/sunrpc/svc.c')
-rw-r--r--net/sunrpc/svc.c155
1 files changed, 72 insertions, 83 deletions
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 812fda9d45..3f2ea7a049 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -438,9 +438,7 @@ EXPORT_SYMBOL_GPL(svc_bind);
static void
__svc_init_bc(struct svc_serv *serv)
{
- INIT_LIST_HEAD(&serv->sv_cb_list);
- spin_lock_init(&serv->sv_cb_lock);
- init_waitqueue_head(&serv->sv_cb_waitq);
+ lwq_init(&serv->sv_cb_list);
}
#else
static void
@@ -509,9 +507,9 @@ __svc_create(struct svc_program *prog, unsigned int bufsize, int npools,
i, serv->sv_name);
pool->sp_id = i;
- INIT_LIST_HEAD(&pool->sp_sockets);
+ lwq_init(&pool->sp_xprts);
INIT_LIST_HEAD(&pool->sp_all_threads);
- spin_lock_init(&pool->sp_lock);
+ init_llist_head(&pool->sp_idle_threads);
percpu_counter_init(&pool->sp_messages_arrived, 0, GFP_KERNEL);
percpu_counter_init(&pool->sp_sockets_queued, 0, GFP_KERNEL);
@@ -575,11 +573,12 @@ svc_destroy(struct kref *ref)
timer_shutdown_sync(&serv->sv_temptimer);
/*
- * The last user is gone and thus all sockets have to be destroyed to
- * the point. Check this.
+ * Remaining transports at this point are not expected.
*/
- BUG_ON(!list_empty(&serv->sv_permsocks));
- BUG_ON(!list_empty(&serv->sv_tempsocks));
+ WARN_ONCE(!list_empty(&serv->sv_permsocks),
+ "SVC: permsocks remain for %s\n", serv->sv_program->pg_name);
+ WARN_ONCE(!list_empty(&serv->sv_tempsocks),
+ "SVC: tempsocks remain for %s\n", serv->sv_program->pg_name);
cache_clean_deferred(serv);
@@ -642,7 +641,6 @@ svc_rqst_alloc(struct svc_serv *serv, struct svc_pool *pool, int node)
folio_batch_init(&rqstp->rq_fbatch);
- __set_bit(RQ_BUSY, &rqstp->rq_flags);
rqstp->rq_server = serv;
rqstp->rq_pool = pool;
@@ -682,10 +680,13 @@ svc_prepare_thread(struct svc_serv *serv, struct svc_pool *pool, int node)
serv->sv_nrthreads += 1;
spin_unlock_bh(&serv->sv_lock);
- spin_lock_bh(&pool->sp_lock);
- pool->sp_nrthreads++;
+ atomic_inc(&pool->sp_nrthreads);
+
+ /* 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;
}
@@ -701,23 +702,25 @@ svc_prepare_thread(struct svc_serv *serv, struct svc_pool *pool, int node)
void svc_pool_wake_idle_thread(struct svc_pool *pool)
{
struct svc_rqst *rqstp;
+ struct llist_node *ln;
rcu_read_lock();
- list_for_each_entry_rcu(rqstp, &pool->sp_all_threads, rq_all) {
- if (test_and_set_bit(RQ_BUSY, &rqstp->rq_flags))
- continue;
-
+ ln = READ_ONCE(pool->sp_idle_threads.first);
+ if (ln) {
+ rqstp = llist_entry(ln, struct svc_rqst, rq_idle);
WRITE_ONCE(rqstp->rq_qtime, ktime_get());
- wake_up_process(rqstp->rq_task);
+ if (!task_is_running(rqstp->rq_task)) {
+ wake_up_process(rqstp->rq_task);
+ trace_svc_wake_up(rqstp->rq_task->pid);
+ percpu_counter_inc(&pool->sp_threads_woken);
+ }
rcu_read_unlock();
- percpu_counter_inc(&pool->sp_threads_woken);
- trace_svc_wake_up(rqstp->rq_task->pid);
return;
}
rcu_read_unlock();
- set_bit(SP_CONGESTED, &pool->sp_flags);
}
+EXPORT_SYMBOL_GPL(svc_pool_wake_idle_thread);
static struct svc_pool *
svc_pool_next(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
@@ -725,36 +728,38 @@ svc_pool_next(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
return pool ? pool : &serv->sv_pools[(*state)++ % serv->sv_nrpools];
}
-static struct task_struct *
-svc_pool_victim(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
+static struct svc_pool *
+svc_pool_victim(struct svc_serv *serv, struct svc_pool *target_pool,
+ unsigned int *state)
{
+ struct svc_pool *pool;
unsigned int i;
- struct task_struct *task = NULL;
+
+retry:
+ pool = target_pool;
if (pool != NULL) {
- spin_lock_bh(&pool->sp_lock);
+ if (atomic_inc_not_zero(&pool->sp_nrthreads))
+ goto found_pool;
+ return NULL;
} else {
for (i = 0; i < serv->sv_nrpools; i++) {
pool = &serv->sv_pools[--(*state) % serv->sv_nrpools];
- spin_lock_bh(&pool->sp_lock);
- if (!list_empty(&pool->sp_all_threads))
+ if (atomic_inc_not_zero(&pool->sp_nrthreads))
goto found_pool;
- spin_unlock_bh(&pool->sp_lock);
}
return NULL;
}
found_pool:
- if (!list_empty(&pool->sp_all_threads)) {
- struct svc_rqst *rqstp;
-
- rqstp = list_entry(pool->sp_all_threads.next, struct svc_rqst, rq_all);
- set_bit(RQ_VICTIM, &rqstp->rq_flags);
- list_del_rcu(&rqstp->rq_all);
- task = rqstp->rq_task;
- }
- spin_unlock_bh(&pool->sp_lock);
- return task;
+ set_bit(SP_VICTIM_REMAINS, &pool->sp_flags);
+ set_bit(SP_NEED_VICTIM, &pool->sp_flags);
+ if (!atomic_dec_and_test(&pool->sp_nrthreads))
+ return pool;
+ /* Nothing left in this pool any more */
+ clear_bit(SP_NEED_VICTIM, &pool->sp_flags);
+ clear_bit(SP_VICTIM_REMAINS, &pool->sp_flags);
+ goto retry;
}
static int
@@ -795,18 +800,16 @@ svc_start_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
static int
svc_stop_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
{
- struct svc_rqst *rqstp;
- struct task_struct *task;
unsigned int state = serv->sv_nrthreads-1;
+ struct svc_pool *victim;
do {
- task = svc_pool_victim(serv, pool, &state);
- if (task == NULL)
+ victim = svc_pool_victim(serv, pool, &state);
+ if (!victim)
break;
- rqstp = kthread_data(task);
- /* Did we lose a race to svo_function threadfn? */
- if (kthread_stop(task) == -EINTR)
- svc_exit_thread(rqstp);
+ svc_pool_wake_idle_thread(victim);
+ wait_on_bit(&victim->sp_flags, SP_VICTIM_REMAINS,
+ TASK_IDLE);
nrservs++;
} while (nrservs < 0);
return 0;
@@ -832,13 +835,10 @@ svc_stop_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
int
svc_set_num_threads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
{
- if (pool == NULL) {
+ if (!pool)
nrservs -= serv->sv_nrthreads;
- } else {
- spin_lock_bh(&pool->sp_lock);
- nrservs -= pool->sp_nrthreads;
- spin_unlock_bh(&pool->sp_lock);
- }
+ else
+ nrservs -= atomic_read(&pool->sp_nrthreads);
if (nrservs > 0)
return svc_start_kthreads(serv, pool, nrservs);
@@ -924,11 +924,9 @@ 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);
- pool->sp_nrthreads--;
- if (!test_and_set_bit(RQ_VICTIM, &rqstp->rq_flags))
- list_del_rcu(&rqstp->rq_all);
- spin_unlock_bh(&pool->sp_lock);
+ list_del_rcu(&rqstp->rq_all);
+
+ atomic_dec(&pool->sp_nrthreads);
spin_lock_bh(&serv->sv_lock);
serv->sv_nrthreads -= 1;
@@ -938,6 +936,11 @@ svc_exit_thread(struct svc_rqst *rqstp)
svc_rqst_free(rqstp);
svc_put(serv);
+ /* That svc_put() cannot be the last, because the thread
+ * waiting for SP_VICTIM_REMAINS to clear must hold
+ * a reference. So it is still safe to access pool.
+ */
+ clear_and_wake_up_bit(SP_VICTIM_REMAINS, &pool->sp_flags);
}
EXPORT_SYMBOL_GPL(svc_exit_thread);
@@ -1544,24 +1547,20 @@ out_drop:
}
#if defined(CONFIG_SUNRPC_BACKCHANNEL)
-/*
- * Process a backchannel RPC request that arrived over an existing
- * outbound connection
+/**
+ * svc_process_bc - process a reverse-direction RPC request
+ * @req: RPC request to be used for client-side processing
+ * @rqstp: server-side execution context
+ *
*/
-int
-bc_svc_process(struct svc_serv *serv, struct rpc_rqst *req,
- struct svc_rqst *rqstp)
+void svc_process_bc(struct rpc_rqst *req, struct svc_rqst *rqstp)
{
struct rpc_task *task;
int proc_error;
- int error;
-
- dprintk("svc: %s(%p)\n", __func__, req);
/* Build the svc_rqst used by the common processing routine */
rqstp->rq_xid = req->rq_xid;
rqstp->rq_prot = req->rq_xprt->prot;
- rqstp->rq_server = serv;
rqstp->rq_bc_net = req->rq_xprt->xprt_net;
rqstp->rq_addrlen = sizeof(req->rq_xprt->addr);
@@ -1590,10 +1589,8 @@ bc_svc_process(struct svc_serv *serv, struct rpc_rqst *req,
* been processed by the caller.
*/
svcxdr_init_decode(rqstp);
- if (!xdr_inline_decode(&rqstp->rq_arg_stream, XDR_UNIT * 2)) {
- error = -EINVAL;
- goto out;
- }
+ if (!xdr_inline_decode(&rqstp->rq_arg_stream, XDR_UNIT * 2))
+ return;
/* Parse and execute the bc call */
proc_error = svc_process_common(rqstp);
@@ -1602,26 +1599,18 @@ bc_svc_process(struct svc_serv *serv, struct rpc_rqst *req,
if (!proc_error) {
/* Processing error: drop the request */
xprt_free_bc_request(req);
- error = -EINVAL;
- goto out;
+ return;
}
/* Finally, send the reply synchronously */
memcpy(&req->rq_snd_buf, &rqstp->rq_res, sizeof(req->rq_snd_buf));
task = rpc_run_bc_task(req);
- if (IS_ERR(task)) {
- error = PTR_ERR(task);
- goto out;
- }
+ if (IS_ERR(task))
+ return;
WARN_ON_ONCE(atomic_read(&task->tk_count) != 1);
- error = task->tk_status;
rpc_put_task(task);
-
-out:
- dprintk("svc: %s(), error=%d\n", __func__, error);
- return error;
}
-EXPORT_SYMBOL_GPL(bc_svc_process);
+EXPORT_SYMBOL_GPL(svc_process_bc);
#endif /* CONFIG_SUNRPC_BACKCHANNEL */
/**