Merge tag 'nfsd-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux

Pull nfsd updates from Chuck Lever:
 "I'm thrilled to announce that the Linux in-kernel NFS server now
  offers NFSv4 write delegations. A write delegation enables a client to
  cache data and metadata for a single file more aggressively, reducing
  network round trips and server workload. Many thanks to Dai Ngo for
  contributing this facility, and to Jeff Layton and Neil Brown for
  reviewing and testing it.

  This release also sees the removal of all support for DES- and
  triple-DES-based Kerberos encryption types in the kernel's SunRPC
  implementation. These encryption types have been deprecated by the
  Internet community for years and are considered insecure. This change
  affects both the in-kernel NFS client and server.

  The server's UDP and TCP socket transports have now fully adopted
  David Howells' new bio_vec iterator so that no more than one sendmsg()
  call is needed to transmit each RPC message. In particular, this helps
  kTLS optimize record boundaries when sending RPC-with-TLS replies, and
  it takes the server a baby step closer to handling file I/O via
  folios.

  We've begun work on overhauling the SunRPC thread scheduler to remove
  a costly linked-list walk when looking for an idle RPC service thread
  to wake. The pre-requisites are included in this release. Thanks to
  Neil Brown for his ongoing work on this improvement"

* tag 'nfsd-6.6' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux: (56 commits)
  Documentation: Add missing documentation for EXPORT_OP flags
  SUNRPC: Remove unused declaration rpc_modcount()
  SUNRPC: Remove unused declarations
  NFSD: da_addr_body field missing in some GETDEVICEINFO replies
  SUNRPC: Remove return value of svc_pool_wake_idle_thread()
  SUNRPC: make rqst_should_sleep() idempotent()
  SUNRPC: Clean up svc_set_num_threads
  SUNRPC: Count ingress RPC messages per svc_pool
  SUNRPC: Deduplicate thread wake-up code
  SUNRPC: Move trace_svc_xprt_enqueue
  SUNRPC: Add enum svc_auth_status
  SUNRPC: change svc_xprt::xpt_flags bits to enum
  SUNRPC: change svc_rqst::rq_flags bits to enum
  SUNRPC: change svc_pool::sp_flags bits to enum
  SUNRPC: change cache_head.flags bits to enum
  SUNRPC: remove timeout arg from svc_recv()
  SUNRPC: change svc_recv() to return void.
  SUNRPC: call svc_process() from svc_recv().
  nfsd: separate nfsd_last_thread() from nfsd_put()
  nfsd: Simplify code around svc_exit_thread() call in nfsd()
  ...

1 files changed, 60 insertions, 37 deletions

diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 587811a002c9..dc21e6c732db 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -513,9 +513,9 @@ __svc_create(struct svc_program *prog, unsigned int bufsize, int npools,
 		INIT_LIST_HEAD(&pool->sp_all_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);
 		percpu_counter_init(&pool->sp_threads_woken, 0, GFP_KERNEL);
-		percpu_counter_init(&pool->sp_threads_timedout, 0, GFP_KERNEL);
 	}
 
 	return serv;
@@ -588,9 +588,9 @@ svc_destroy(struct kref *ref)
 	for (i = 0; i < serv->sv_nrpools; i++) {
 		struct svc_pool *pool = &serv->sv_pools[i];
 
+		percpu_counter_destroy(&pool->sp_messages_arrived);
 		percpu_counter_destroy(&pool->sp_sockets_queued);
 		percpu_counter_destroy(&pool->sp_threads_woken);
-		percpu_counter_destroy(&pool->sp_threads_timedout);
 	}
 	kfree(serv->sv_pools);
 	kfree(serv);
@@ -689,23 +689,44 @@ svc_prepare_thread(struct svc_serv *serv, struct svc_pool *pool, int node)
 	return rqstp;
 }
 
-/*
- * Choose a pool in which to create a new thread, for svc_set_num_threads
+/**
+ * svc_pool_wake_idle_thread - Awaken an idle thread in @pool
+ * @pool: service thread pool
+ *
+ * Can be called from soft IRQ or process context. Finding an idle
+ * service thread and marking it BUSY is atomic with respect to
+ * other calls to svc_pool_wake_idle_thread().
+ *
  */
-static inline struct svc_pool *
-choose_pool(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
+void svc_pool_wake_idle_thread(struct svc_pool *pool)
 {
-	if (pool != NULL)
-		return pool;
+	struct svc_rqst	*rqstp;
+
+	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;
+
+		WRITE_ONCE(rqstp->rq_qtime, ktime_get());
+		wake_up_process(rqstp->rq_task);
+		rcu_read_unlock();
+		percpu_counter_inc(&pool->sp_threads_woken);
+		trace_svc_wake_up(rqstp->rq_task->pid);
+		return;
+	}
+	rcu_read_unlock();
 
-	return &serv->sv_pools[(*state)++ % serv->sv_nrpools];
+	set_bit(SP_CONGESTED, &pool->sp_flags);
 }
 
-/*
- * Choose a thread to kill, for svc_set_num_threads
- */
-static inline struct task_struct *
-choose_victim(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
+static struct svc_pool *
+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)
 {
 	unsigned int i;
 	struct task_struct *task = NULL;
@@ -713,7 +734,6 @@ choose_victim(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
 	if (pool != NULL) {
 		spin_lock_bh(&pool->sp_lock);
 	} else {
-		/* choose a pool in round-robin fashion */
 		for (i = 0; i < serv->sv_nrpools; i++) {
 			pool = &serv->sv_pools[--(*state) % serv->sv_nrpools];
 			spin_lock_bh(&pool->sp_lock);
@@ -728,21 +748,15 @@ found_pool:
 	if (!list_empty(&pool->sp_all_threads)) {
 		struct svc_rqst *rqstp;
 
-		/*
-		 * Remove from the pool->sp_all_threads list
-		 * so we don't try to kill it again.
-		 */
 		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;
 }
 
-/* create new threads */
 static int
 svc_start_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
 {
@@ -754,13 +768,12 @@ svc_start_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
 
 	do {
 		nrservs--;
-		chosen_pool = choose_pool(serv, pool, &state);
-
+		chosen_pool = svc_pool_next(serv, pool, &state);
 		node = svc_pool_map_get_node(chosen_pool->sp_id);
+
 		rqstp = svc_prepare_thread(serv, chosen_pool, node);
 		if (IS_ERR(rqstp))
 			return PTR_ERR(rqstp);
-
 		task = kthread_create_on_node(serv->sv_threadfn, rqstp,
 					      node, "%s", serv->sv_name);
 		if (IS_ERR(task)) {
@@ -779,15 +792,6 @@ svc_start_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
 	return 0;
 }
 
-/*
- * Create or destroy enough new threads to make the number
- * of threads the given number.  If `pool' is non-NULL, applies
- * only to threads in that pool, otherwise round-robins between
- * all pools.  Caller must ensure that mutual exclusion between this and
- * server startup or shutdown.
- */
-
-/* destroy old threads */
 static int
 svc_stop_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
 {
@@ -795,9 +799,8 @@ svc_stop_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
 	struct task_struct *task;
 	unsigned int state = serv->sv_nrthreads-1;
 
-	/* destroy old threads */
 	do {
-		task = choose_victim(serv, pool, &state);
+		task = svc_pool_victim(serv, pool, &state);
 		if (task == NULL)
 			break;
 		rqstp = kthread_data(task);
@@ -809,6 +812,23 @@ svc_stop_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
 	return 0;
 }
 
+/**
+ * svc_set_num_threads - adjust number of threads per RPC service
+ * @serv: RPC service to adjust
+ * @pool: Specific pool from which to choose threads, or NULL
+ * @nrservs: New number of threads for @serv (0 or less means kill all threads)
+ *
+ * Create or destroy threads to make the number of threads for @serv the
+ * given number. If @pool is non-NULL, change only threads in that pool;
+ * otherwise, round-robin between all pools for @serv. @serv's
+ * sv_nrthreads is adjusted for each thread created or destroyed.
+ *
+ * Caller must ensure mutual exclusion between this and server startup or
+ * shutdown.
+ *
+ * Returns zero on success or a negative errno if an error occurred while
+ * starting a thread.
+ */
 int
 svc_set_num_threads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
 {
@@ -1277,8 +1297,9 @@ svc_process_common(struct svc_rqst *rqstp)
 	const struct svc_procedure *procp = NULL;
 	struct svc_serv		*serv = rqstp->rq_server;
 	struct svc_process_info process;
-	int			auth_res, rc;
+	enum svc_auth_status	auth_res;
 	unsigned int		aoffset;
+	int			rc;
 	__be32			*p;
 
 	/* Will be turned off by GSS integrity and privacy services */
@@ -1333,6 +1354,9 @@ svc_process_common(struct svc_rqst *rqstp)
 		goto dropit;
 	case SVC_COMPLETE:
 		goto sendit;
+	default:
+		pr_warn_once("Unexpected svc_auth_status (%d)\n", auth_res);
+		goto err_system_err;
 	}
 
 	if (progp == NULL)
@@ -1516,7 +1540,6 @@ out_baddir:
 out_drop:
 	svc_drop(rqstp);
 }
-EXPORT_SYMBOL_GPL(svc_process);
 
 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
 /*