/*
   * Copyright (c) 2006 Oracle.  All rights reserved.
   *
   * This software is available to you under a choice of one of two
   * licenses.  You may choose to be licensed under the terms of the GNU
   * General Public License (GPL) Version 2, available from the file
   * COPYING in the main directory of this source tree, or the
   * OpenIB.org BSD license below:
   *
   *     Redistribution and use in source and binary forms, with or
   *     without modification, are permitted provided that the following
   *     conditions are met:
   *
   *      - Redistributions of source code must retain the above
   *        copyright notice, this list of conditions and the following
   *        disclaimer.
   *
   *      - Redistributions in binary form must reproduce the above
   *        copyright notice, this list of conditions and the following
   *        disclaimer in the documentation and/or other materials
   *        provided with the distribution.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
   * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
   * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   *
   */
  #include <linux/percpu.h>
  #include <linux/seq_file.h>
  #include <linux/proc_fs.h>
  #include <linux/export.h>
  
  #include "rds.h"
  
  DEFINE_PER_CPU_SHARED_ALIGNED(struct rds_statistics, rds_stats);
  EXPORT_PER_CPU_SYMBOL_GPL(rds_stats);
  
  /* :.,$s/unsigned long\>.*\<s_\(.*\);/"\1",/g */
  
  static const char *const rds_stat_names[] = {
  	"conn_reset",
  	"recv_drop_bad_checksum",
  	"recv_drop_old_seq",
  	"recv_drop_no_sock",
  	"recv_drop_dead_sock",
  	"recv_deliver_raced",
  	"recv_delivered",
  	"recv_queued",
  	"recv_immediate_retry",
  	"recv_delayed_retry",
  	"recv_ack_required",
  	"recv_rdma_bytes",
  	"recv_ping",
  	"send_queue_empty",
  	"send_queue_full",
  	"send_lock_contention",
  	"send_lock_queue_raced",
  	"send_immediate_retry",
  	"send_delayed_retry",
  	"send_drop_acked",
  	"send_ack_required",
  	"send_queued",
  	"send_rdma",
  	"send_rdma_bytes",
  	"send_pong",
  	"page_remainder_hit",
  	"page_remainder_miss",
  	"copy_to_user",
  	"copy_from_user",
  	"cong_update_queued",
  	"cong_update_received",
  	"cong_send_error",
  	"cong_send_blocked",
  };
  
  void rds_stats_info_copy(struct rds_info_iterator *iter,
  			 uint64_t *values, const char *const *names, size_t nr)
  {
  	struct rds_info_counter ctr;
  	size_t i;
  
  	for (i = 0; i < nr; i++) {
  		BUG_ON(strlen(names[i]) >= sizeof(ctr.name));
  		strncpy(ctr.name, names[i], sizeof(ctr.name) - 1);
  		ctr.name[sizeof(ctr.name) - 1] = '\0';
  		ctr.value = values[i];
  
  		rds_info_copy(iter, &ctr, sizeof(ctr));
  	}
  }
  EXPORT_SYMBOL_GPL(rds_stats_info_copy);
  
  /*
   * This gives global counters across all the transports.  The strings
   * are copied in so that the tool doesn't need knowledge of the specific
   * stats that we're exporting.  Some are pretty implementation dependent
   * and may change over time.  That doesn't stop them from being useful.
   *
   * This is the only function in the chain that knows about the byte granular
   * length in userspace.  It converts it to number of stat entries that the
   * rest of the functions operate in.
   */
  static void rds_stats_info(struct socket *sock, unsigned int len,
  			   struct rds_info_iterator *iter,
  			   struct rds_info_lengths *lens)
  {
  	struct rds_statistics stats = {0, };
  	uint64_t *src;
  	uint64_t *sum;
  	size_t i;
  	int cpu;
  	unsigned int avail;
  
  	avail = len / sizeof(struct rds_info_counter);
  
  	if (avail < ARRAY_SIZE(rds_stat_names)) {
  		avail = 0;
  		goto trans;
  	}
  
  	for_each_online_cpu(cpu) {
  		src = (uint64_t *)&(per_cpu(rds_stats, cpu));
  		sum = (uint64_t *)&stats;
  		for (i = 0; i < sizeof(stats) / sizeof(uint64_t); i++)
  			*(sum++) += *(src++);
  	}
  
  	rds_stats_info_copy(iter, (uint64_t *)&stats, rds_stat_names,
  			    ARRAY_SIZE(rds_stat_names));
  	avail -= ARRAY_SIZE(rds_stat_names);
  
  trans:
  	lens->each = sizeof(struct rds_info_counter);
  	lens->nr = rds_trans_stats_info_copy(iter, avail) +
  		   ARRAY_SIZE(rds_stat_names);
  }
  
  void rds_stats_exit(void)
  {
  	rds_info_deregister_func(RDS_INFO_COUNTERS, rds_stats_info);
  }
  
  int rds_stats_init(void)
  {
  	rds_info_register_func(RDS_INFO_COUNTERS, rds_stats_info);
  	return 0;
  }