scftorture: Count single_rpc offline failures in statistics outputgrafted

scf_torture_stats_print() aggregates each invoker thread's counters
into a local scf_statistics structure before printing, but the
n_single_rpc_ofl field is missing from the aggregation loop.  As a
result, the "single_rpc_ofl" value printed in the statistics line is
always zero, even when smp_call_function_single() invocations for the
RPC test have failed due to offline CPUs and been counted by the
invoker threads.

Add the missing accumulation so that the printed value reflects the
actual counts.

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

1 files changed, 256 insertions, 0 deletions

diff --git a/fs/netfs/objects.c b/fs/netfs/objects.c
new file mode 100644
index 000000000..b8c4918d3
--- /dev/null
+++ b/fs/netfs/objects.c
@@ -0,0 +1,256 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Object lifetime handling and tracing.
+ *
+ * Copyright (C) 2022 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <linux/slab.h>
+#include <linux/mempool.h>
+#include <linux/delay.h>
+#include "internal.h"
+
+static void netfs_free_request(struct work_struct *work);
+
+/*
+ * Allocate an I/O request and initialise it.
+ */
+struct netfs_io_request *netfs_alloc_request(struct address_space *mapping,
+					     struct file *file,
+					     loff_t start, size_t len,
+					     enum netfs_io_origin origin)
+{
+	static atomic_t debug_ids;
+	struct inode *inode = file ? file_inode(file) : mapping->host;
+	struct netfs_inode *ctx = netfs_inode(inode);
+	struct netfs_io_request *rreq;
+	mempool_t *mempool = ctx->ops->request_pool ?: &netfs_request_pool;
+	struct kmem_cache *cache = mempool->pool_data;
+	int ret;
+
+	for (;;) {
+		rreq = mempool_alloc(mempool, GFP_KERNEL);
+		if (rreq)
+			break;
+		msleep(10);
+	}
+
+	memset(rreq, 0, kmem_cache_size(cache));
+	INIT_WORK(&rreq->cleanup_work, netfs_free_request);
+	rreq->start	= start;
+	rreq->len	= len;
+	rreq->origin	= origin;
+	rreq->netfs_ops	= ctx->ops;
+	rreq->mapping	= mapping;
+	rreq->inode	= inode;
+	rreq->i_size	= i_size_read(inode);
+	rreq->debug_id	= atomic_inc_return(&debug_ids);
+	rreq->wsize	= INT_MAX;
+	rreq->io_streams[0].sreq_max_len = ULONG_MAX;
+	rreq->io_streams[0].sreq_max_segs = 0;
+	spin_lock_init(&rreq->lock);
+	INIT_LIST_HEAD(&rreq->io_streams[0].subrequests);
+	INIT_LIST_HEAD(&rreq->io_streams[1].subrequests);
+	init_waitqueue_head(&rreq->waitq);
+	refcount_set(&rreq->ref, 2);
+
+	if (origin == NETFS_READAHEAD ||
+	    origin == NETFS_READPAGE ||
+	    origin == NETFS_READ_GAPS ||
+	    origin == NETFS_READ_SINGLE ||
+	    origin == NETFS_READ_FOR_WRITE ||
+	    origin == NETFS_UNBUFFERED_READ ||
+	    origin == NETFS_DIO_READ) {
+		INIT_WORK(&rreq->work, netfs_read_collection_worker);
+		rreq->io_streams[0].avail = true;
+	} else {
+		INIT_WORK(&rreq->work, netfs_write_collection_worker);
+	}
+
+	__set_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags);
+	if (rreq->netfs_ops->init_request) {
+		ret = rreq->netfs_ops->init_request(rreq, file);
+		if (ret < 0) {
+			mempool_free(rreq, rreq->netfs_ops->request_pool ?: &netfs_request_pool);
+			return ERR_PTR(ret);
+		}
+	}
+
+	atomic_inc(&ctx->io_count);
+	trace_netfs_rreq_ref(rreq->debug_id, refcount_read(&rreq->ref), netfs_rreq_trace_new);
+	netfs_proc_add_rreq(rreq);
+	netfs_stat(&netfs_n_rh_rreq);
+	return rreq;
+}
+
+void netfs_get_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace what)
+{
+	int r;
+
+	__refcount_inc(&rreq->ref, &r);
+	trace_netfs_rreq_ref(rreq->debug_id, r + 1, what);
+}
+
+void netfs_clear_subrequests(struct netfs_io_request *rreq)
+{
+	struct netfs_io_subrequest *subreq;
+	struct netfs_io_stream *stream;
+	int s;
+
+	for (s = 0; s < ARRAY_SIZE(rreq->io_streams); s++) {
+		stream = &rreq->io_streams[s];
+		while (!list_empty(&stream->subrequests)) {
+			subreq = list_first_entry(&stream->subrequests,
+						  struct netfs_io_subrequest, rreq_link);
+			list_del(&subreq->rreq_link);
+			netfs_put_subrequest(subreq, netfs_sreq_trace_put_clear);
+		}
+	}
+}
+
+static void netfs_free_request_rcu(struct rcu_head *rcu)
+{
+	struct netfs_io_request *rreq = container_of(rcu, struct netfs_io_request, rcu);
+
+	mempool_free(rreq, rreq->netfs_ops->request_pool ?: &netfs_request_pool);
+	netfs_stat_d(&netfs_n_rh_rreq);
+}
+
+static void netfs_deinit_request(struct netfs_io_request *rreq)
+{
+	struct netfs_inode *ictx = netfs_inode(rreq->inode);
+	unsigned int i;
+
+	trace_netfs_rreq(rreq, netfs_rreq_trace_free);
+
+	/* Cancel/flush the result collection worker.  That does not carry a
+	 * ref of its own, so we must wait for it somewhere.
+	 */
+	cancel_work_sync(&rreq->work);
+
+	netfs_proc_del_rreq(rreq);
+	netfs_clear_subrequests(rreq);
+	if (rreq->netfs_ops->free_request)
+		rreq->netfs_ops->free_request(rreq);
+	if (rreq->cache_resources.ops)
+		rreq->cache_resources.ops->end_operation(&rreq->cache_resources);
+	if (rreq->direct_bv) {
+		for (i = 0; i < rreq->direct_bv_count; i++) {
+			if (rreq->direct_bv[i].bv_page) {
+				if (rreq->direct_bv_unpin)
+					unpin_user_page(rreq->direct_bv[i].bv_page);
+			}
+		}
+		kvfree(rreq->direct_bv);
+	}
+	rolling_buffer_clear(&rreq->buffer);
+
+	if (atomic_dec_and_test(&ictx->io_count))
+		wake_up_var(&ictx->io_count);
+}
+
+static void netfs_free_request(struct work_struct *work)
+{
+	struct netfs_io_request *rreq =
+		container_of(work, struct netfs_io_request, cleanup_work);
+
+	netfs_deinit_request(rreq);
+	call_rcu(&rreq->rcu, netfs_free_request_rcu);
+}
+
+void netfs_put_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace what)
+{
+	unsigned int debug_id;
+	bool dead;
+	int r;
+
+	if (rreq) {
+		debug_id = rreq->debug_id;
+		dead = __refcount_dec_and_test(&rreq->ref, &r);
+		trace_netfs_rreq_ref(debug_id, r - 1, what);
+		if (dead)
+			WARN_ON(!queue_work(system_dfl_wq, &rreq->cleanup_work));
+	}
+}
+
+/*
+ * Free a request (synchronously) that was just allocated but has
+ * failed before it could be submitted.
+ */
+void netfs_put_failed_request(struct netfs_io_request *rreq)
+{
+	int r = refcount_read(&rreq->ref);
+
+	/* new requests have two references (see
+	 * netfs_alloc_request(), and this function is only allowed on
+	 * new request objects
+	 */
+	WARN_ON_ONCE(r != 2);
+
+	trace_netfs_rreq_ref(rreq->debug_id, r, netfs_rreq_trace_put_failed);
+	netfs_free_request(&rreq->cleanup_work);
+}
+
+/*
+ * Allocate and partially initialise an I/O request structure.
+ */
+struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq)
+{
+	struct netfs_io_subrequest *subreq;
+	mempool_t *mempool = rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool;
+	struct kmem_cache *cache = mempool->pool_data;
+
+	for (;;) {
+		subreq = mempool_alloc(rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool,
+				       GFP_KERNEL);
+		if (subreq)
+			break;
+		msleep(10);
+	}
+
+	memset(subreq, 0, kmem_cache_size(cache));
+	INIT_WORK(&subreq->work, NULL);
+	INIT_LIST_HEAD(&subreq->rreq_link);
+	refcount_set(&subreq->ref, 2);
+	subreq->rreq = rreq;
+	subreq->debug_index = atomic_inc_return(&rreq->subreq_counter);
+	netfs_get_request(rreq, netfs_rreq_trace_get_subreq);
+	netfs_stat(&netfs_n_rh_sreq);
+	return subreq;
+}
+
+void netfs_get_subrequest(struct netfs_io_subrequest *subreq,
+			  enum netfs_sreq_ref_trace what)
+{
+	int r;
+
+	__refcount_inc(&subreq->ref, &r);
+	trace_netfs_sreq_ref(subreq->rreq->debug_id, subreq->debug_index, r + 1,
+			     what);
+}
+
+static void netfs_free_subrequest(struct netfs_io_subrequest *subreq)
+{
+	struct netfs_io_request *rreq = subreq->rreq;
+
+	trace_netfs_sreq(subreq, netfs_sreq_trace_free);
+	if (rreq->netfs_ops->free_subrequest)
+		rreq->netfs_ops->free_subrequest(subreq);
+	mempool_free(subreq, rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool);
+	netfs_stat_d(&netfs_n_rh_sreq);
+	netfs_put_request(rreq, netfs_rreq_trace_put_subreq);
+}
+
+void netfs_put_subrequest(struct netfs_io_subrequest *subreq,
+			  enum netfs_sreq_ref_trace what)
+{
+	unsigned int debug_index = subreq->debug_index;
+	unsigned int debug_id = subreq->rreq->debug_id;
+	bool dead;
+	int r;
+
+	dead = __refcount_dec_and_test(&subreq->ref, &r);
+	trace_netfs_sreq_ref(debug_id, debug_index, r - 1, what);
+	if (dead)
+		netfs_free_subrequest(subreq);
+}