/*
 * Copyright (c) 2005-2006 Network Appliance, Inc. 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 BSD-type
 * 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.
 *
 *      Neither the name of the Network Appliance, Inc. nor the names of
 *      its contributors may be used to endorse or promote products
 *      derived from this software without specific prior written
 *      permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Author: Tom Tucker <tom@opengridcomputing.com>
 */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/sysctl.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/sched.h>
#include <linux/sunrpc/svc_rdma.h>

#define RPCDBG_FACILITY RPCDBG_SVCXPRT

/* RPC/RDMA parameters */
unsigned int svcrdma_ord = RPCRDMA_ORD;
static unsigned int min_ord = 1;
static unsigned int max_ord = 4096;
unsigned int svcrdma_max_requests = RPCRDMA_MAX_REQUESTS;
static unsigned int min_max_requests = 4;
static unsigned int max_max_requests = 16384;
unsigned int svcrdma_max_req_size = RPCRDMA_MAX_REQ_SIZE;
static unsigned int min_max_inline = 4096;
static unsigned int max_max_inline = 65536;

atomic_t rdma_stat_recv;
atomic_t rdma_stat_read;
atomic_t rdma_stat_write;
atomic_t rdma_stat_sq_starve;
atomic_t rdma_stat_rq_starve;
atomic_t rdma_stat_rq_poll;
atomic_t rdma_stat_rq_prod;
atomic_t rdma_stat_sq_poll;
atomic_t rdma_stat_sq_prod;

/* Temporary NFS request map and context caches */
struct kmem_cache *svc_rdma_map_cachep;
struct kmem_cache *svc_rdma_ctxt_cachep;

/*
 * This function implements reading and resetting an atomic_t stat
 * variable through read/write to a proc file. Any write to the file
 * resets the associated statistic to zero. Any read returns it's
 * current value.
 */
static int read_reset_stat(ctl_table *table, int write,
                           void __user *buffer, size_t *lenp,
                           loff_t *ppos)
{
        atomic_t *stat = (atomic_t *)table->data;

        if (!stat)
                return -EINVAL;

        if (write)
                atomic_set(stat, 0);
        else {
                char str_buf[32];
                char *data;
                int len = snprintf(str_buf, 32, "%d\n", atomic_read(stat));
                if (len >= 32)
                        return -EFAULT;
                len = strlen(str_buf);
                if (*ppos > len) {
                        *lenp = 0;
                        return 0;
                }
                data = &str_buf[*ppos];
                len -= *ppos;
                if (len > *lenp)
                        len = *lenp;
                if (len && copy_to_user(buffer, str_buf, len))
                        return -EFAULT;
                *lenp = len;
                *ppos += len;
        }
        return 0;
}

static struct ctl_table_header *svcrdma_table_header;
static ctl_table svcrdma_parm_table[] = {
        {
                .procname       = "max_requests",
                .data           = &svcrdma_max_requests,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = &sysctl_intvec,
                .extra1         = &min_max_requests,
                .extra2         = &max_max_requests
        },
        {
                .procname       = "max_req_size",
                .data           = &svcrdma_max_req_size,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = &sysctl_intvec,
                .extra1         = &min_max_inline,
                .extra2         = &max_max_inline
        },
        {
                .procname       = "max_outbound_read_requests",
                .data           = &svcrdma_ord,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = &sysctl_intvec,
                .extra1         = &min_ord,
                .extra2         = &max_ord,
        },

        {
                .procname       = "rdma_stat_read",
                .data           = &rdma_stat_read,
                .maxlen         = sizeof(atomic_t),
                .mode           = 0644,
                .proc_handler   = &read_reset_stat,
        },
        {
                .procname       = "rdma_stat_recv",
                .data           = &rdma_stat_recv,
                .maxlen         = sizeof(atomic_t),
                .mode           = 0644,
                .proc_handler   = &read_reset_stat,
        },
        {
                .procname       = "rdma_stat_write",
                .data           = &rdma_stat_write,
                .maxlen         = sizeof(atomic_t),
                .mode           = 0644,
                .proc_handler   = &read_reset_stat,
        },
        {
                .procname       = "rdma_stat_sq_starve",
                .data           = &rdma_stat_sq_starve,
                .maxlen         = sizeof(atomic_t),
                .mode           = 0644,
                .proc_handler   = &read_reset_stat,
        },
        {
                .procname       = "rdma_stat_rq_starve",
                .data           = &rdma_stat_rq_starve,
                .maxlen         = sizeof(atomic_t),
                .mode           = 0644,
                .proc_handler   = &read_reset_stat,
        },
        {
                .procname       = "rdma_stat_rq_poll",
                .data           = &rdma_stat_rq_poll,
                .maxlen         = sizeof(atomic_t),
                .mode           = 0644,
                .proc_handler   = &read_reset_stat,
        },
        {
                .procname       = "rdma_stat_rq_prod",
                .data           = &rdma_stat_rq_prod,
                .maxlen         = sizeof(atomic_t),
                .mode           = 0644,
                .proc_handler   = &read_reset_stat,
        },
        {
                .procname       = "rdma_stat_sq_poll",
                .data           = &rdma_stat_sq_poll,
                .maxlen         = sizeof(atomic_t),
                .mode           = 0644,
                .proc_handler   = &read_reset_stat,
        },
        {
                .procname       = "rdma_stat_sq_prod",
                .data           = &rdma_stat_sq_prod,
                .maxlen         = sizeof(atomic_t),
                .mode           = 0644,
                .proc_handler   = &read_reset_stat,
        },
        {
                .ctl_name = 0,
        },
};

static ctl_table svcrdma_table[] = {
        {
                .procname       = "svc_rdma",
                .mode           = 0555,
                .child          = svcrdma_parm_table
        },
        {
                .ctl_name = 0,
        },
};

static ctl_table svcrdma_root_table[] = {
        {
                .ctl_name       = CTL_SUNRPC,
                .procname       = "sunrpc",
                .mode           = 0555,
                .child          = svcrdma_table
        },
        {
                .ctl_name = 0,
        },
};

void svc_rdma_cleanup(void)
{
        dprintk("SVCRDMA Module Removed, deregister RPC RDMA transport\n");
        flush_scheduled_work();
        if (svcrdma_table_header) {
                unregister_sysctl_table(svcrdma_table_header);
                svcrdma_table_header = NULL;
        }
        svc_unreg_xprt_class(&svc_rdma_class);
        kmem_cache_destroy(svc_rdma_map_cachep);
        kmem_cache_destroy(svc_rdma_ctxt_cachep);
}

int svc_rdma_init(void)
{
        dprintk("SVCRDMA Module Init, register RPC RDMA transport\n");
        dprintk("\tsvcrdma_ord      : %d\n", svcrdma_ord);
        dprintk("\tmax_requests     : %d\n", svcrdma_max_requests);
        dprintk("\tsq_depth         : %d\n",
                svcrdma_max_requests * RPCRDMA_SQ_DEPTH_MULT);
        dprintk("\tmax_inline       : %d\n", svcrdma_max_req_size);
        if (!svcrdma_table_header)
                svcrdma_table_header =
                        register_sysctl_table(svcrdma_root_table);

        /* Create the temporary map cache */
        svc_rdma_map_cachep = kmem_cache_create("svc_rdma_map_cache",
                                                sizeof(struct svc_rdma_req_map),
                                                0,
                                                SLAB_HWCACHE_ALIGN,
                                                NULL);
        if (!svc_rdma_map_cachep) {
                printk(KERN_INFO "Could not allocate map cache.\n");
                goto err0;
        }

        /* Create the temporary context cache */
        svc_rdma_ctxt_cachep =
                kmem_cache_create("svc_rdma_ctxt_cache",
                                  sizeof(struct svc_rdma_op_ctxt),
                                  0,
                                  SLAB_HWCACHE_ALIGN,
                                  NULL);
        if (!svc_rdma_ctxt_cachep) {
                printk(KERN_INFO "Could not allocate WR ctxt cache.\n");
                goto err1;
        }

        /* Register RDMA with the SVC transport switch */
        svc_reg_xprt_class(&svc_rdma_class);
        return 0;
 err1:
        kmem_cache_destroy(svc_rdma_map_cachep);
 err0:
        unregister_sysctl_table(svcrdma_table_header);
        return -ENOMEM;
}
MODULE_AUTHOR("Tom Tucker <tom@opengridcomputing.com>");
MODULE_DESCRIPTION("SVC RDMA Transport");
MODULE_LICENSE("Dual BSD/GPL");
module_init(svc_rdma_init);
module_exit(svc_rdma_cleanup);