Free Electrons

Embedded Linux Experts

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
/*
 * 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/kernel.h>
#include <linux/in.h>
#include <linux/if.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.h>
#include <linux/if_arp.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/module.h>

#include "rds.h"
#include "ib.h"

static unsigned int fmr_pool_size = RDS_FMR_POOL_SIZE;
unsigned int fmr_message_size = RDS_FMR_SIZE + 1; /* +1 allows for unaligned MRs */
unsigned int rds_ib_retry_count = RDS_IB_DEFAULT_RETRY_COUNT;

module_param(fmr_pool_size, int, 0444);
MODULE_PARM_DESC(fmr_pool_size, " Max number of fmr per HCA");
module_param(fmr_message_size, int, 0444);
MODULE_PARM_DESC(fmr_message_size, " Max size of a RDMA transfer");
module_param(rds_ib_retry_count, int, 0444);
MODULE_PARM_DESC(rds_ib_retry_count, " Number of hw retries before reporting an error");

/*
 * we have a clumsy combination of RCU and a rwsem protecting this list
 * because it is used both in the get_mr fast path and while blocking in
 * the FMR flushing path.
 */
DECLARE_RWSEM(rds_ib_devices_lock);
struct list_head rds_ib_devices;

/* NOTE: if also grabbing ibdev lock, grab this first */
DEFINE_SPINLOCK(ib_nodev_conns_lock);
LIST_HEAD(ib_nodev_conns);

static void rds_ib_nodev_connect(void)
{
	struct rds_ib_connection *ic;

	spin_lock(&ib_nodev_conns_lock);
	list_for_each_entry(ic, &ib_nodev_conns, ib_node)
		rds_conn_connect_if_down(ic->conn);
	spin_unlock(&ib_nodev_conns_lock);
}

static void rds_ib_dev_shutdown(struct rds_ib_device *rds_ibdev)
{
	struct rds_ib_connection *ic;
	unsigned long flags;

	spin_lock_irqsave(&rds_ibdev->spinlock, flags);
	list_for_each_entry(ic, &rds_ibdev->conn_list, ib_node)
		rds_conn_drop(ic->conn);
	spin_unlock_irqrestore(&rds_ibdev->spinlock, flags);
}

/*
 * rds_ib_destroy_mr_pool() blocks on a few things and mrs drop references
 * from interrupt context so we push freing off into a work struct in krdsd.
 */
static void rds_ib_dev_free(struct work_struct *work)
{
	struct rds_ib_ipaddr *i_ipaddr, *i_next;
	struct rds_ib_device *rds_ibdev = container_of(work,
					struct rds_ib_device, free_work);

	if (rds_ibdev->mr_pool)
		rds_ib_destroy_mr_pool(rds_ibdev->mr_pool);
	if (rds_ibdev->mr)
		ib_dereg_mr(rds_ibdev->mr);
	if (rds_ibdev->pd)
		ib_dealloc_pd(rds_ibdev->pd);

	list_for_each_entry_safe(i_ipaddr, i_next, &rds_ibdev->ipaddr_list, list) {
		list_del(&i_ipaddr->list);
		kfree(i_ipaddr);
	}

	kfree(rds_ibdev);
}

void rds_ib_dev_put(struct rds_ib_device *rds_ibdev)
{
	BUG_ON(atomic_read(&rds_ibdev->refcount) <= 0);
	if (atomic_dec_and_test(&rds_ibdev->refcount))
		queue_work(rds_wq, &rds_ibdev->free_work);
}

static void rds_ib_add_one(struct ib_device *device)
{
	struct rds_ib_device *rds_ibdev;
	struct ib_device_attr *dev_attr;

	/* Only handle IB (no iWARP) devices */
	if (device->node_type != RDMA_NODE_IB_CA)
		return;

	dev_attr = kmalloc(sizeof *dev_attr, GFP_KERNEL);
	if (!dev_attr)
		return;

	if (ib_query_device(device, dev_attr)) {
		rdsdebug("Query device failed for %s\n", device->name);
		goto free_attr;
	}

	rds_ibdev = kzalloc_node(sizeof(struct rds_ib_device), GFP_KERNEL,
				 ibdev_to_node(device));
	if (!rds_ibdev)
		goto free_attr;

	spin_lock_init(&rds_ibdev->spinlock);
	atomic_set(&rds_ibdev->refcount, 1);
	INIT_WORK(&rds_ibdev->free_work, rds_ib_dev_free);

	rds_ibdev->max_wrs = dev_attr->max_qp_wr;
	rds_ibdev->max_sge = min(dev_attr->max_sge, RDS_IB_MAX_SGE);

	rds_ibdev->fmr_max_remaps = dev_attr->max_map_per_fmr?: 32;
	rds_ibdev->max_fmrs = dev_attr->max_fmr ?
			min_t(unsigned int, dev_attr->max_fmr, fmr_pool_size) :
			fmr_pool_size;

	rds_ibdev->max_initiator_depth = dev_attr->max_qp_init_rd_atom;
	rds_ibdev->max_responder_resources = dev_attr->max_qp_rd_atom;

	rds_ibdev->dev = device;
	rds_ibdev->pd = ib_alloc_pd(device);
	if (IS_ERR(rds_ibdev->pd)) {
		rds_ibdev->pd = NULL;
		goto put_dev;
	}

	rds_ibdev->mr = ib_get_dma_mr(rds_ibdev->pd, IB_ACCESS_LOCAL_WRITE);
	if (IS_ERR(rds_ibdev->mr)) {
		rds_ibdev->mr = NULL;
		goto put_dev;
	}

	rds_ibdev->mr_pool = rds_ib_create_mr_pool(rds_ibdev);
	if (IS_ERR(rds_ibdev->mr_pool)) {
		rds_ibdev->mr_pool = NULL;
		goto put_dev;
	}

	INIT_LIST_HEAD(&rds_ibdev->ipaddr_list);
	INIT_LIST_HEAD(&rds_ibdev->conn_list);

	down_write(&rds_ib_devices_lock);
	list_add_tail_rcu(&rds_ibdev->list, &rds_ib_devices);
	up_write(&rds_ib_devices_lock);
	atomic_inc(&rds_ibdev->refcount);

	ib_set_client_data(device, &rds_ib_client, rds_ibdev);
	atomic_inc(&rds_ibdev->refcount);

	rds_ib_nodev_connect();

put_dev:
	rds_ib_dev_put(rds_ibdev);
free_attr:
	kfree(dev_attr);
}

/*
 * New connections use this to find the device to associate with the
 * connection.  It's not in the fast path so we're not concerned about the
 * performance of the IB call.  (As of this writing, it uses an interrupt
 * blocking spinlock to serialize walking a per-device list of all registered
 * clients.)
 *
 * RCU is used to handle incoming connections racing with device teardown.
 * Rather than use a lock to serialize removal from the client_data and
 * getting a new reference, we use an RCU grace period.  The destruction
 * path removes the device from client_data and then waits for all RCU
 * readers to finish.
 *
 * A new connection can get NULL from this if its arriving on a
 * device that is in the process of being removed.
 */
struct rds_ib_device *rds_ib_get_client_data(struct ib_device *device)
{
	struct rds_ib_device *rds_ibdev;

	rcu_read_lock();
	rds_ibdev = ib_get_client_data(device, &rds_ib_client);
	if (rds_ibdev)
		atomic_inc(&rds_ibdev->refcount);
	rcu_read_unlock();
	return rds_ibdev;
}

/*
 * The IB stack is letting us know that a device is going away.  This can
 * happen if the underlying HCA driver is removed or if PCI hotplug is removing
 * the pci function, for example.
 *
 * This can be called at any time and can be racing with any other RDS path.
 */
static void rds_ib_remove_one(struct ib_device *device)
{
	struct rds_ib_device *rds_ibdev;

	rds_ibdev = ib_get_client_data(device, &rds_ib_client);
	if (!rds_ibdev)
		return;

	rds_ib_dev_shutdown(rds_ibdev);

	/* stop connection attempts from getting a reference to this device. */
	ib_set_client_data(device, &rds_ib_client, NULL);

	down_write(&rds_ib_devices_lock);
	list_del_rcu(&rds_ibdev->list);
	up_write(&rds_ib_devices_lock);

	/*
	 * This synchronize rcu is waiting for readers of both the ib
	 * client data and the devices list to finish before we drop
	 * both of those references.
	 */
	synchronize_rcu();
	rds_ib_dev_put(rds_ibdev);
	rds_ib_dev_put(rds_ibdev);
}

struct ib_client rds_ib_client = {
	.name   = "rds_ib",
	.add    = rds_ib_add_one,
	.remove = rds_ib_remove_one
};

static int rds_ib_conn_info_visitor(struct rds_connection *conn,
				    void *buffer)
{
	struct rds_info_rdma_connection *iinfo = buffer;
	struct rds_ib_connection *ic;

	/* We will only ever look at IB transports */
	if (conn->c_trans != &rds_ib_transport)
		return 0;

	iinfo->src_addr = conn->c_laddr;
	iinfo->dst_addr = conn->c_faddr;

	memset(&iinfo->src_gid, 0, sizeof(iinfo->src_gid));
	memset(&iinfo->dst_gid, 0, sizeof(iinfo->dst_gid));
	if (rds_conn_state(conn) == RDS_CONN_UP) {
		struct rds_ib_device *rds_ibdev;
		struct rdma_dev_addr *dev_addr;

		ic = conn->c_transport_data;
		dev_addr = &ic->i_cm_id->route.addr.dev_addr;

		rdma_addr_get_sgid(dev_addr, (union ib_gid *) &iinfo->src_gid);
		rdma_addr_get_dgid(dev_addr, (union ib_gid *) &iinfo->dst_gid);

		rds_ibdev = ic->rds_ibdev;
		iinfo->max_send_wr = ic->i_send_ring.w_nr;
		iinfo->max_recv_wr = ic->i_recv_ring.w_nr;
		iinfo->max_send_sge = rds_ibdev->max_sge;
		rds_ib_get_mr_info(rds_ibdev, iinfo);
	}
	return 1;
}

static void rds_ib_ic_info(struct socket *sock, unsigned int len,
			   struct rds_info_iterator *iter,
			   struct rds_info_lengths *lens)
{
	rds_for_each_conn_info(sock, len, iter, lens,
				rds_ib_conn_info_visitor,
				sizeof(struct rds_info_rdma_connection));
}


/*
 * Early RDS/IB was built to only bind to an address if there is an IPoIB
 * device with that address set.
 *
 * If it were me, I'd advocate for something more flexible.  Sending and
 * receiving should be device-agnostic.  Transports would try and maintain
 * connections between peers who have messages queued.  Userspace would be
 * allowed to influence which paths have priority.  We could call userspace
 * asserting this policy "routing".
 */
static int rds_ib_laddr_check(__be32 addr)
{
	int ret;
	struct rdma_cm_id *cm_id;
	struct sockaddr_in sin;

	/* Create a CMA ID and try to bind it. This catches both
	 * IB and iWARP capable NICs.
	 */
	cm_id = rdma_create_id(NULL, NULL, RDMA_PS_TCP, IB_QPT_RC);
	if (IS_ERR(cm_id))
		return PTR_ERR(cm_id);

	memset(&sin, 0, sizeof(sin));
	sin.sin_family = AF_INET;
	sin.sin_addr.s_addr = addr;

	/* rdma_bind_addr will only succeed for IB & iWARP devices */
	ret = rdma_bind_addr(cm_id, (struct sockaddr *)&sin);
	/* due to this, we will claim to support iWARP devices unless we
	   check node_type. */
	if (ret || !cm_id->device ||
	    cm_id->device->node_type != RDMA_NODE_IB_CA)
		ret = -EADDRNOTAVAIL;

	rdsdebug("addr %pI4 ret %d node type %d\n",
		&addr, ret,
		cm_id->device ? cm_id->device->node_type : -1);

	rdma_destroy_id(cm_id);

	return ret;
}

static void rds_ib_unregister_client(void)
{
	ib_unregister_client(&rds_ib_client);
	/* wait for rds_ib_dev_free() to complete */
	flush_workqueue(rds_wq);
}

void rds_ib_exit(void)
{
	rds_info_deregister_func(RDS_INFO_IB_CONNECTIONS, rds_ib_ic_info);
	rds_ib_unregister_client();
	rds_ib_destroy_nodev_conns();
	rds_ib_sysctl_exit();
	rds_ib_recv_exit();
	rds_trans_unregister(&rds_ib_transport);
}

struct rds_transport rds_ib_transport = {
	.laddr_check		= rds_ib_laddr_check,
	.xmit_complete		= rds_ib_xmit_complete,
	.xmit			= rds_ib_xmit,
	.xmit_rdma		= rds_ib_xmit_rdma,
	.xmit_atomic		= rds_ib_xmit_atomic,
	.recv			= rds_ib_recv,
	.conn_alloc		= rds_ib_conn_alloc,
	.conn_free		= rds_ib_conn_free,
	.conn_connect		= rds_ib_conn_connect,
	.conn_shutdown		= rds_ib_conn_shutdown,
	.inc_copy_to_user	= rds_ib_inc_copy_to_user,
	.inc_free		= rds_ib_inc_free,
	.cm_initiate_connect	= rds_ib_cm_initiate_connect,
	.cm_handle_connect	= rds_ib_cm_handle_connect,
	.cm_connect_complete	= rds_ib_cm_connect_complete,
	.stats_info_copy	= rds_ib_stats_info_copy,
	.exit			= rds_ib_exit,
	.get_mr			= rds_ib_get_mr,
	.sync_mr		= rds_ib_sync_mr,
	.free_mr		= rds_ib_free_mr,
	.flush_mrs		= rds_ib_flush_mrs,
	.t_owner		= THIS_MODULE,
	.t_name			= "infiniband",
	.t_type			= RDS_TRANS_IB
};

int rds_ib_init(void)
{
	int ret;

	INIT_LIST_HEAD(&rds_ib_devices);

	ret = ib_register_client(&rds_ib_client);
	if (ret)
		goto out;

	ret = rds_ib_sysctl_init();
	if (ret)
		goto out_ibreg;

	ret = rds_ib_recv_init();
	if (ret)
		goto out_sysctl;

	ret = rds_trans_register(&rds_ib_transport);
	if (ret)
		goto out_recv;

	rds_info_register_func(RDS_INFO_IB_CONNECTIONS, rds_ib_ic_info);

	goto out;

out_recv:
	rds_ib_recv_exit();
out_sysctl:
	rds_ib_sysctl_exit();
out_ibreg:
	rds_ib_unregister_client();
out:
	return ret;
}

MODULE_LICENSE("GPL");