linux/net/rds/ib.c
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   1/*
   2 * Copyright (c) 2006 Oracle.  All rights reserved.
   3 *
   4 * This software is available to you under a choice of one of two
   5 * licenses.  You may choose to be licensed under the terms of the GNU
   6 * General Public License (GPL) Version 2, available from the file
   7 * COPYING in the main directory of this source tree, or the
   8 * OpenIB.org BSD license below:
   9 *
  10 *     Redistribution and use in source and binary forms, with or
  11 *     without modification, are permitted provided that the following
  12 *     conditions are met:
  13 *
  14 *      - Redistributions of source code must retain the above
  15 *        copyright notice, this list of conditions and the following
  16 *        disclaimer.
  17 *
  18 *      - Redistributions in binary form must reproduce the above
  19 *        copyright notice, this list of conditions and the following
  20 *        disclaimer in the documentation and/or other materials
  21 *        provided with the distribution.
  22 *
  23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  30 * SOFTWARE.
  31 *
  32 */
  33#include <linux/kernel.h>
  34#include <linux/in.h>
  35#include <linux/if.h>
  36#include <linux/netdevice.h>
  37#include <linux/inetdevice.h>
  38#include <linux/if_arp.h>
  39#include <linux/delay.h>
  40#include <linux/slab.h>
  41#include <linux/module.h>
  42
  43#include "rds.h"
  44#include "ib.h"
  45
  46static unsigned int fmr_pool_size = RDS_FMR_POOL_SIZE;
  47unsigned int fmr_message_size = RDS_FMR_SIZE + 1; /* +1 allows for unaligned MRs */
  48unsigned int rds_ib_retry_count = RDS_IB_DEFAULT_RETRY_COUNT;
  49
  50module_param(fmr_pool_size, int, 0444);
  51MODULE_PARM_DESC(fmr_pool_size, " Max number of fmr per HCA");
  52module_param(fmr_message_size, int, 0444);
  53MODULE_PARM_DESC(fmr_message_size, " Max size of a RDMA transfer");
  54module_param(rds_ib_retry_count, int, 0444);
  55MODULE_PARM_DESC(rds_ib_retry_count, " Number of hw retries before reporting an error");
  56
  57/*
  58 * we have a clumsy combination of RCU and a rwsem protecting this list
  59 * because it is used both in the get_mr fast path and while blocking in
  60 * the FMR flushing path.
  61 */
  62DECLARE_RWSEM(rds_ib_devices_lock);
  63struct list_head rds_ib_devices;
  64
  65/* NOTE: if also grabbing ibdev lock, grab this first */
  66DEFINE_SPINLOCK(ib_nodev_conns_lock);
  67LIST_HEAD(ib_nodev_conns);
  68
  69static void rds_ib_nodev_connect(void)
  70{
  71        struct rds_ib_connection *ic;
  72
  73        spin_lock(&ib_nodev_conns_lock);
  74        list_for_each_entry(ic, &ib_nodev_conns, ib_node)
  75                rds_conn_connect_if_down(ic->conn);
  76        spin_unlock(&ib_nodev_conns_lock);
  77}
  78
  79static void rds_ib_dev_shutdown(struct rds_ib_device *rds_ibdev)
  80{
  81        struct rds_ib_connection *ic;
  82        unsigned long flags;
  83
  84        spin_lock_irqsave(&rds_ibdev->spinlock, flags);
  85        list_for_each_entry(ic, &rds_ibdev->conn_list, ib_node)
  86                rds_conn_drop(ic->conn);
  87        spin_unlock_irqrestore(&rds_ibdev->spinlock, flags);
  88}
  89
  90/*
  91 * rds_ib_destroy_mr_pool() blocks on a few things and mrs drop references
  92 * from interrupt context so we push freing off into a work struct in krdsd.
  93 */
  94static void rds_ib_dev_free(struct work_struct *work)
  95{
  96        struct rds_ib_ipaddr *i_ipaddr, *i_next;
  97        struct rds_ib_device *rds_ibdev = container_of(work,
  98                                        struct rds_ib_device, free_work);
  99
 100        if (rds_ibdev->mr_pool)
 101                rds_ib_destroy_mr_pool(rds_ibdev->mr_pool);
 102        if (rds_ibdev->mr)
 103                ib_dereg_mr(rds_ibdev->mr);
 104        if (rds_ibdev->pd)
 105                ib_dealloc_pd(rds_ibdev->pd);
 106
 107        list_for_each_entry_safe(i_ipaddr, i_next, &rds_ibdev->ipaddr_list, list) {
 108                list_del(&i_ipaddr->list);
 109                kfree(i_ipaddr);
 110        }
 111
 112        kfree(rds_ibdev);
 113}
 114
 115void rds_ib_dev_put(struct rds_ib_device *rds_ibdev)
 116{
 117        BUG_ON(atomic_read(&rds_ibdev->refcount) <= 0);
 118        if (atomic_dec_and_test(&rds_ibdev->refcount))
 119                queue_work(rds_wq, &rds_ibdev->free_work);
 120}
 121
 122static void rds_ib_add_one(struct ib_device *device)
 123{
 124        struct rds_ib_device *rds_ibdev;
 125        struct ib_device_attr *dev_attr;
 126
 127        /* Only handle IB (no iWARP) devices */
 128        if (device->node_type != RDMA_NODE_IB_CA)
 129                return;
 130
 131        dev_attr = kmalloc(sizeof *dev_attr, GFP_KERNEL);
 132        if (!dev_attr)
 133                return;
 134
 135        if (ib_query_device(device, dev_attr)) {
 136                rdsdebug("Query device failed for %s\n", device->name);
 137                goto free_attr;
 138        }
 139
 140        rds_ibdev = kzalloc_node(sizeof(struct rds_ib_device), GFP_KERNEL,
 141                                 ibdev_to_node(device));
 142        if (!rds_ibdev)
 143                goto free_attr;
 144
 145        spin_lock_init(&rds_ibdev->spinlock);
 146        atomic_set(&rds_ibdev->refcount, 1);
 147        INIT_WORK(&rds_ibdev->free_work, rds_ib_dev_free);
 148
 149        rds_ibdev->max_wrs = dev_attr->max_qp_wr;
 150        rds_ibdev->max_sge = min(dev_attr->max_sge, RDS_IB_MAX_SGE);
 151
 152        rds_ibdev->fmr_max_remaps = dev_attr->max_map_per_fmr?: 32;
 153        rds_ibdev->max_fmrs = dev_attr->max_fmr ?
 154                        min_t(unsigned int, dev_attr->max_fmr, fmr_pool_size) :
 155                        fmr_pool_size;
 156
 157        rds_ibdev->max_initiator_depth = dev_attr->max_qp_init_rd_atom;
 158        rds_ibdev->max_responder_resources = dev_attr->max_qp_rd_atom;
 159
 160        rds_ibdev->dev = device;
 161        rds_ibdev->pd = ib_alloc_pd(device);
 162        if (IS_ERR(rds_ibdev->pd)) {
 163                rds_ibdev->pd = NULL;
 164                goto put_dev;
 165        }
 166
 167        rds_ibdev->mr = ib_get_dma_mr(rds_ibdev->pd, IB_ACCESS_LOCAL_WRITE);
 168        if (IS_ERR(rds_ibdev->mr)) {
 169                rds_ibdev->mr = NULL;
 170                goto put_dev;
 171        }
 172
 173        rds_ibdev->mr_pool = rds_ib_create_mr_pool(rds_ibdev);
 174        if (IS_ERR(rds_ibdev->mr_pool)) {
 175                rds_ibdev->mr_pool = NULL;
 176                goto put_dev;
 177        }
 178
 179        INIT_LIST_HEAD(&rds_ibdev->ipaddr_list);
 180        INIT_LIST_HEAD(&rds_ibdev->conn_list);
 181
 182        down_write(&rds_ib_devices_lock);
 183        list_add_tail_rcu(&rds_ibdev->list, &rds_ib_devices);
 184        up_write(&rds_ib_devices_lock);
 185        atomic_inc(&rds_ibdev->refcount);
 186
 187        ib_set_client_data(device, &rds_ib_client, rds_ibdev);
 188        atomic_inc(&rds_ibdev->refcount);
 189
 190        rds_ib_nodev_connect();
 191
 192put_dev:
 193        rds_ib_dev_put(rds_ibdev);
 194free_attr:
 195        kfree(dev_attr);
 196}
 197
 198/*
 199 * New connections use this to find the device to associate with the
 200 * connection.  It's not in the fast path so we're not concerned about the
 201 * performance of the IB call.  (As of this writing, it uses an interrupt
 202 * blocking spinlock to serialize walking a per-device list of all registered
 203 * clients.)
 204 *
 205 * RCU is used to handle incoming connections racing with device teardown.
 206 * Rather than use a lock to serialize removal from the client_data and
 207 * getting a new reference, we use an RCU grace period.  The destruction
 208 * path removes the device from client_data and then waits for all RCU
 209 * readers to finish.
 210 *
 211 * A new connection can get NULL from this if its arriving on a
 212 * device that is in the process of being removed.
 213 */
 214struct rds_ib_device *rds_ib_get_client_data(struct ib_device *device)
 215{
 216        struct rds_ib_device *rds_ibdev;
 217
 218        rcu_read_lock();
 219        rds_ibdev = ib_get_client_data(device, &rds_ib_client);
 220        if (rds_ibdev)
 221                atomic_inc(&rds_ibdev->refcount);
 222        rcu_read_unlock();
 223        return rds_ibdev;
 224}
 225
 226/*
 227 * The IB stack is letting us know that a device is going away.  This can
 228 * happen if the underlying HCA driver is removed or if PCI hotplug is removing
 229 * the pci function, for example.
 230 *
 231 * This can be called at any time and can be racing with any other RDS path.
 232 */
 233static void rds_ib_remove_one(struct ib_device *device)
 234{
 235        struct rds_ib_device *rds_ibdev;
 236
 237        rds_ibdev = ib_get_client_data(device, &rds_ib_client);
 238        if (!rds_ibdev)
 239                return;
 240
 241        rds_ib_dev_shutdown(rds_ibdev);
 242
 243        /* stop connection attempts from getting a reference to this device. */
 244        ib_set_client_data(device, &rds_ib_client, NULL);
 245
 246        down_write(&rds_ib_devices_lock);
 247        list_del_rcu(&rds_ibdev->list);
 248        up_write(&rds_ib_devices_lock);
 249
 250        /*
 251         * This synchronize rcu is waiting for readers of both the ib
 252         * client data and the devices list to finish before we drop
 253         * both of those references.
 254         */
 255        synchronize_rcu();
 256        rds_ib_dev_put(rds_ibdev);
 257        rds_ib_dev_put(rds_ibdev);
 258}
 259
 260struct ib_client rds_ib_client = {
 261        .name   = "rds_ib",
 262        .add    = rds_ib_add_one,
 263        .remove = rds_ib_remove_one
 264};
 265
 266static int rds_ib_conn_info_visitor(struct rds_connection *conn,
 267                                    void *buffer)
 268{
 269        struct rds_info_rdma_connection *iinfo = buffer;
 270        struct rds_ib_connection *ic;
 271
 272        /* We will only ever look at IB transports */
 273        if (conn->c_trans != &rds_ib_transport)
 274                return 0;
 275
 276        iinfo->src_addr = conn->c_laddr;
 277        iinfo->dst_addr = conn->c_faddr;
 278
 279        memset(&iinfo->src_gid, 0, sizeof(iinfo->src_gid));
 280        memset(&iinfo->dst_gid, 0, sizeof(iinfo->dst_gid));
 281        if (rds_conn_state(conn) == RDS_CONN_UP) {
 282                struct rds_ib_device *rds_ibdev;
 283                struct rdma_dev_addr *dev_addr;
 284
 285                ic = conn->c_transport_data;
 286                dev_addr = &ic->i_cm_id->route.addr.dev_addr;
 287
 288                rdma_addr_get_sgid(dev_addr, (union ib_gid *) &iinfo->src_gid);
 289                rdma_addr_get_dgid(dev_addr, (union ib_gid *) &iinfo->dst_gid);
 290
 291                rds_ibdev = ic->rds_ibdev;
 292                iinfo->max_send_wr = ic->i_send_ring.w_nr;
 293                iinfo->max_recv_wr = ic->i_recv_ring.w_nr;
 294                iinfo->max_send_sge = rds_ibdev->max_sge;
 295                rds_ib_get_mr_info(rds_ibdev, iinfo);
 296        }
 297        return 1;
 298}
 299
 300static void rds_ib_ic_info(struct socket *sock, unsigned int len,
 301                           struct rds_info_iterator *iter,
 302                           struct rds_info_lengths *lens)
 303{
 304        rds_for_each_conn_info(sock, len, iter, lens,
 305                                rds_ib_conn_info_visitor,
 306                                sizeof(struct rds_info_rdma_connection));
 307}
 308
 309
 310/*
 311 * Early RDS/IB was built to only bind to an address if there is an IPoIB
 312 * device with that address set.
 313 *
 314 * If it were me, I'd advocate for something more flexible.  Sending and
 315 * receiving should be device-agnostic.  Transports would try and maintain
 316 * connections between peers who have messages queued.  Userspace would be
 317 * allowed to influence which paths have priority.  We could call userspace
 318 * asserting this policy "routing".
 319 */
 320static int rds_ib_laddr_check(__be32 addr)
 321{
 322        int ret;
 323        struct rdma_cm_id *cm_id;
 324        struct sockaddr_in sin;
 325
 326        /* Create a CMA ID and try to bind it. This catches both
 327         * IB and iWARP capable NICs.
 328         */
 329        cm_id = rdma_create_id(NULL, NULL, RDMA_PS_TCP, IB_QPT_RC);
 330        if (IS_ERR(cm_id))
 331                return PTR_ERR(cm_id);
 332
 333        memset(&sin, 0, sizeof(sin));
 334        sin.sin_family = AF_INET;
 335        sin.sin_addr.s_addr = addr;
 336
 337        /* rdma_bind_addr will only succeed for IB & iWARP devices */
 338        ret = rdma_bind_addr(cm_id, (struct sockaddr *)&sin);
 339        /* due to this, we will claim to support iWARP devices unless we
 340           check node_type. */
 341        if (ret || cm_id->device->node_type != RDMA_NODE_IB_CA)
 342                ret = -EADDRNOTAVAIL;
 343
 344        rdsdebug("addr %pI4 ret %d node type %d\n",
 345                &addr, ret,
 346                cm_id->device ? cm_id->device->node_type : -1);
 347
 348        rdma_destroy_id(cm_id);
 349
 350        return ret;
 351}
 352
 353static void rds_ib_unregister_client(void)
 354{
 355        ib_unregister_client(&rds_ib_client);
 356        /* wait for rds_ib_dev_free() to complete */
 357        flush_workqueue(rds_wq);
 358}
 359
 360void rds_ib_exit(void)
 361{
 362        rds_info_deregister_func(RDS_INFO_IB_CONNECTIONS, rds_ib_ic_info);
 363        rds_ib_unregister_client();
 364        rds_ib_destroy_nodev_conns();
 365        rds_ib_sysctl_exit();
 366        rds_ib_recv_exit();
 367        rds_trans_unregister(&rds_ib_transport);
 368}
 369
 370struct rds_transport rds_ib_transport = {
 371        .laddr_check            = rds_ib_laddr_check,
 372        .xmit_complete          = rds_ib_xmit_complete,
 373        .xmit                   = rds_ib_xmit,
 374        .xmit_rdma              = rds_ib_xmit_rdma,
 375        .xmit_atomic            = rds_ib_xmit_atomic,
 376        .recv                   = rds_ib_recv,
 377        .conn_alloc             = rds_ib_conn_alloc,
 378        .conn_free              = rds_ib_conn_free,
 379        .conn_connect           = rds_ib_conn_connect,
 380        .conn_shutdown          = rds_ib_conn_shutdown,
 381        .inc_copy_to_user       = rds_ib_inc_copy_to_user,
 382        .inc_free               = rds_ib_inc_free,
 383        .cm_initiate_connect    = rds_ib_cm_initiate_connect,
 384        .cm_handle_connect      = rds_ib_cm_handle_connect,
 385        .cm_connect_complete    = rds_ib_cm_connect_complete,
 386        .stats_info_copy        = rds_ib_stats_info_copy,
 387        .exit                   = rds_ib_exit,
 388        .get_mr                 = rds_ib_get_mr,
 389        .sync_mr                = rds_ib_sync_mr,
 390        .free_mr                = rds_ib_free_mr,
 391        .flush_mrs              = rds_ib_flush_mrs,
 392        .t_owner                = THIS_MODULE,
 393        .t_name                 = "infiniband",
 394        .t_type                 = RDS_TRANS_IB
 395};
 396
 397int rds_ib_init(void)
 398{
 399        int ret;
 400
 401        INIT_LIST_HEAD(&rds_ib_devices);
 402
 403        ret = ib_register_client(&rds_ib_client);
 404        if (ret)
 405                goto out;
 406
 407        ret = rds_ib_sysctl_init();
 408        if (ret)
 409                goto out_ibreg;
 410
 411        ret = rds_ib_recv_init();
 412        if (ret)
 413                goto out_sysctl;
 414
 415        ret = rds_trans_register(&rds_ib_transport);
 416        if (ret)
 417                goto out_recv;
 418
 419        rds_info_register_func(RDS_INFO_IB_CONNECTIONS, rds_ib_ic_info);
 420
 421        goto out;
 422
 423out_recv:
 424        rds_ib_recv_exit();
 425out_sysctl:
 426        rds_ib_sysctl_exit();
 427out_ibreg:
 428        rds_ib_unregister_client();
 429out:
 430        return ret;
 431}
 432
 433MODULE_LICENSE("GPL");
 434
 435
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