summaryrefslogtreecommitdiff
path: root/drivers/net/ethernet/sfc/rx.c
blob: c01916cff5076e4015fa77e1904ecc8177253fe2 (plain)
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
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
// SPDX-License-Identifier: GPL-2.0-only
/****************************************************************************
 * Driver for Solarflare network controllers and boards
 * Copyright 2005-2006 Fen Systems Ltd.
 * Copyright 2005-2013 Solarflare Communications Inc.
 */

#include <linux/socket.h>
#include <linux/in.h>
#include <linux/slab.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/prefetch.h>
#include <linux/moduleparam.h>
#include <linux/iommu.h>
#include <net/ip.h>
#include <net/checksum.h>
#include <net/xdp.h>
#include <linux/bpf_trace.h>
#include "net_driver.h"
#include "efx.h"
#include "rx_common.h"
#include "filter.h"
#include "nic.h"
#include "selftest.h"
#include "workarounds.h"

/* Preferred number of descriptors to fill at once */
#define EFX_RX_PREFERRED_BATCH 8U

/* Maximum rx prefix used by any architecture. */
#define EFX_MAX_RX_PREFIX_SIZE 16

/* Size of buffer allocated for skb header area. */
#define EFX_SKB_HEADERS  128u

/* Each packet can consume up to ceil(max_frame_len / buffer_size) buffers */
#define EFX_RX_MAX_FRAGS DIV_ROUND_UP(EFX_MAX_FRAME_LEN(EFX_MAX_MTU), \
				      EFX_RX_USR_BUF_SIZE)

static inline void efx_sync_rx_buffer(struct efx_nic *efx,
				      struct efx_rx_buffer *rx_buf,
				      unsigned int len)
{
	dma_sync_single_for_cpu(&efx->pci_dev->dev, rx_buf->dma_addr, len,
				DMA_FROM_DEVICE);
}

static void efx_rx_packet__check_len(struct efx_rx_queue *rx_queue,
				     struct efx_rx_buffer *rx_buf,
				     int len)
{
	struct efx_nic *efx = rx_queue->efx;
	unsigned max_len = rx_buf->len - efx->type->rx_buffer_padding;

	if (likely(len <= max_len))
		return;

	/* The packet must be discarded, but this is only a fatal error
	 * if the caller indicated it was
	 */
	rx_buf->flags |= EFX_RX_PKT_DISCARD;

	if (net_ratelimit())
		netif_err(efx, rx_err, efx->net_dev,
			  "RX queue %d overlength RX event (%#x > %#x)\n",
			  efx_rx_queue_index(rx_queue), len, max_len);

	efx_rx_queue_channel(rx_queue)->n_rx_overlength++;
}

/* Allocate and construct an SKB around page fragments */
static struct sk_buff *efx_rx_mk_skb(struct efx_channel *channel,
				     struct efx_rx_buffer *rx_buf,
				     unsigned int n_frags,
				     u8 *eh, int hdr_len)
{
	struct efx_nic *efx = channel->efx;
	struct sk_buff *skb;

	/* Allocate an SKB to store the headers */
	skb = netdev_alloc_skb(efx->net_dev,
			       efx->rx_ip_align + efx->rx_prefix_size +
			       hdr_len);
	if (unlikely(skb == NULL)) {
		atomic_inc(&efx->n_rx_noskb_drops);
		return NULL;
	}

	EFX_WARN_ON_ONCE_PARANOID(rx_buf->len < hdr_len);

	memcpy(skb->data + efx->rx_ip_align, eh - efx->rx_prefix_size,
	       efx->rx_prefix_size + hdr_len);
	skb_reserve(skb, efx->rx_ip_align + efx->rx_prefix_size);
	__skb_put(skb, hdr_len);

	/* Append the remaining page(s) onto the frag list */
	if (rx_buf->len > hdr_len) {
		rx_buf->page_offset += hdr_len;
		rx_buf->len -= hdr_len;

		for (;;) {
			skb_fill_page_desc(skb, skb_shinfo(skb)->nr_frags,
					   rx_buf->page, rx_buf->page_offset,
					   rx_buf->len);
			rx_buf->page = NULL;
			skb->len += rx_buf->len;
			skb->data_len += rx_buf->len;
			if (skb_shinfo(skb)->nr_frags == n_frags)
				break;

			rx_buf = efx_rx_buf_next(&channel->rx_queue, rx_buf);
		}
	} else {
		__free_pages(rx_buf->page, efx->rx_buffer_order);
		rx_buf->page = NULL;
		n_frags = 0;
	}

	skb->truesize += n_frags * efx->rx_buffer_truesize;

	/* Move past the ethernet header */
	skb->protocol = eth_type_trans(skb, efx->net_dev);

	skb_mark_napi_id(skb, &channel->napi_str);

	return skb;
}

void efx_rx_packet(struct efx_rx_queue *rx_queue, unsigned int index,
		   unsigned int n_frags, unsigned int len, u16 flags)
{
	struct efx_nic *efx = rx_queue->efx;
	struct efx_channel *channel = efx_rx_queue_channel(rx_queue);
	struct efx_rx_buffer *rx_buf;

	rx_queue->rx_packets++;

	rx_buf = efx_rx_buffer(rx_queue, index);
	rx_buf->flags |= flags;

	/* Validate the number of fragments and completed length */
	if (n_frags == 1) {
		if (!(flags & EFX_RX_PKT_PREFIX_LEN))
			efx_rx_packet__check_len(rx_queue, rx_buf, len);
	} else if (unlikely(n_frags > EFX_RX_MAX_FRAGS) ||
		   unlikely(len <= (n_frags - 1) * efx->rx_dma_len) ||
		   unlikely(len > n_frags * efx->rx_dma_len) ||
		   unlikely(!efx->rx_scatter)) {
		/* If this isn't an explicit discard request, either
		 * the hardware or the driver is broken.
		 */
		WARN_ON(!(len == 0 && rx_buf->flags & EFX_RX_PKT_DISCARD));
		rx_buf->flags |= EFX_RX_PKT_DISCARD;
	}

	netif_vdbg(efx, rx_status, efx->net_dev,
		   "RX queue %d received ids %x-%x len %d %s%s\n",
		   efx_rx_queue_index(rx_queue), index,
		   (index + n_frags - 1) & rx_queue->ptr_mask, len,
		   (rx_buf->flags & EFX_RX_PKT_CSUMMED) ? " [SUMMED]" : "",
		   (rx_buf->flags & EFX_RX_PKT_DISCARD) ? " [DISCARD]" : "");

	/* Discard packet, if instructed to do so.  Process the
	 * previous receive first.
	 */
	if (unlikely(rx_buf->flags & EFX_RX_PKT_DISCARD)) {
		efx_rx_flush_packet(channel);
		efx_discard_rx_packet(channel, rx_buf, n_frags);
		return;
	}

	if (n_frags == 1 && !(flags & EFX_RX_PKT_PREFIX_LEN))
		rx_buf->len = len;

	/* Release and/or sync the DMA mapping - assumes all RX buffers
	 * consumed in-order per RX queue.
	 */
	efx_sync_rx_buffer(efx, rx_buf, rx_buf->len);

	/* Prefetch nice and early so data will (hopefully) be in cache by
	 * the time we look at it.
	 */
	prefetch(efx_rx_buf_va(rx_buf));

	rx_buf->page_offset += efx->rx_prefix_size;
	rx_buf->len -= efx->rx_prefix_size;

	if (n_frags > 1) {
		/* Release/sync DMA mapping for additional fragments.
		 * Fix length for last fragment.
		 */
		unsigned int tail_frags = n_frags - 1;

		for (;;) {
			rx_buf = efx_rx_buf_next(rx_queue, rx_buf);
			if (--tail_frags == 0)
				break;
			efx_sync_rx_buffer(efx, rx_buf, efx->rx_dma_len);
		}
		rx_buf->len = len - (n_frags - 1) * efx->rx_dma_len;
		efx_sync_rx_buffer(efx, rx_buf, rx_buf->len);
	}

	/* All fragments have been DMA-synced, so recycle pages. */
	rx_buf = efx_rx_buffer(rx_queue, index);
	efx_recycle_rx_pages(channel, rx_buf, n_frags);

	/* Pipeline receives so that we give time for packet headers to be
	 * prefetched into cache.
	 */
	efx_rx_flush_packet(channel);
	channel->rx_pkt_n_frags = n_frags;
	channel->rx_pkt_index = index;
}

static void efx_rx_deliver(struct efx_channel *channel, u8 *eh,
			   struct efx_rx_buffer *rx_buf,
			   unsigned int n_frags)
{
	struct sk_buff *skb;
	u16 hdr_len = min_t(u16, rx_buf->len, EFX_SKB_HEADERS);

	skb = efx_rx_mk_skb(channel, rx_buf, n_frags, eh, hdr_len);
	if (unlikely(skb == NULL)) {
		struct efx_rx_queue *rx_queue;

		rx_queue = efx_channel_get_rx_queue(channel);
		efx_free_rx_buffers(rx_queue, rx_buf, n_frags);
		return;
	}
	skb_record_rx_queue(skb, channel->rx_queue.core_index);

	/* Set the SKB flags */
	skb_checksum_none_assert(skb);
	if (likely(rx_buf->flags & EFX_RX_PKT_CSUMMED)) {
		skb->ip_summed = CHECKSUM_UNNECESSARY;
		skb->csum_level = !!(rx_buf->flags & EFX_RX_PKT_CSUM_LEVEL);
	}

	efx_rx_skb_attach_timestamp(channel, skb);

	if (channel->type->receive_skb)
		if (channel->type->receive_skb(channel, skb))
			return;

	/* Pass the packet up */
	if (channel->rx_list != NULL)
		/* Add to list, will pass up later */
		list_add_tail(&skb->list, channel->rx_list);
	else
		/* No list, so pass it up now */
		netif_receive_skb(skb);
}

/** efx_do_xdp: perform XDP processing on a received packet
 *
 * Returns true if packet should still be delivered.
 */
static bool efx_do_xdp(struct efx_nic *efx, struct efx_channel *channel,
		       struct efx_rx_buffer *rx_buf, u8 **ehp)
{
	u8 rx_prefix[EFX_MAX_RX_PREFIX_SIZE];
	struct efx_rx_queue *rx_queue;
	struct bpf_prog *xdp_prog;
	struct xdp_frame *xdpf;
	struct xdp_buff xdp;
	u32 xdp_act;
	s16 offset;
	int err;

	rcu_read_lock();
	xdp_prog = rcu_dereference(efx->xdp_prog);
	if (!xdp_prog) {
		rcu_read_unlock();
		return true;
	}

	rx_queue = efx_channel_get_rx_queue(channel);

	if (unlikely(channel->rx_pkt_n_frags > 1)) {
		/* We can't do XDP on fragmented packets - drop. */
		rcu_read_unlock();
		efx_free_rx_buffers(rx_queue, rx_buf,
				    channel->rx_pkt_n_frags);
		if (net_ratelimit())
			netif_err(efx, rx_err, efx->net_dev,
				  "XDP is not possible with multiple receive fragments (%d)\n",
				  channel->rx_pkt_n_frags);
		channel->n_rx_xdp_bad_drops++;
		return false;
	}

	dma_sync_single_for_cpu(&efx->pci_dev->dev, rx_buf->dma_addr,
				rx_buf->len, DMA_FROM_DEVICE);

	/* Save the rx prefix. */
	EFX_WARN_ON_PARANOID(efx->rx_prefix_size > EFX_MAX_RX_PREFIX_SIZE);
	memcpy(rx_prefix, *ehp - efx->rx_prefix_size,
	       efx->rx_prefix_size);

	xdp.data = *ehp;
	xdp.data_hard_start = xdp.data - EFX_XDP_HEADROOM;

	/* No support yet for XDP metadata */
	xdp_set_data_meta_invalid(&xdp);
	xdp.data_end = xdp.data + rx_buf->len;
	xdp.rxq = &rx_queue->xdp_rxq_info;
	xdp.frame_sz = efx->rx_page_buf_step;

	xdp_act = bpf_prog_run_xdp(xdp_prog, &xdp);
	rcu_read_unlock();

	offset = (u8 *)xdp.data - *ehp;

	switch (xdp_act) {
	case XDP_PASS:
		/* Fix up rx prefix. */
		if (offset) {
			*ehp += offset;
			rx_buf->page_offset += offset;
			rx_buf->len -= offset;
			memcpy(*ehp - efx->rx_prefix_size, rx_prefix,
			       efx->rx_prefix_size);
		}
		break;

	case XDP_TX:
		/* Buffer ownership passes to tx on success. */
		xdpf = xdp_convert_buff_to_frame(&xdp);
		err = efx_xdp_tx_buffers(efx, 1, &xdpf, true);
		if (unlikely(err != 1)) {
			efx_free_rx_buffers(rx_queue, rx_buf, 1);
			if (net_ratelimit())
				netif_err(efx, rx_err, efx->net_dev,
					  "XDP TX failed (%d)\n", err);
			channel->n_rx_xdp_bad_drops++;
			trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act);
		} else {
			channel->n_rx_xdp_tx++;
		}
		break;

	case XDP_REDIRECT:
		err = xdp_do_redirect(efx->net_dev, &xdp, xdp_prog);
		if (unlikely(err)) {
			efx_free_rx_buffers(rx_queue, rx_buf, 1);
			if (net_ratelimit())
				netif_err(efx, rx_err, efx->net_dev,
					  "XDP redirect failed (%d)\n", err);
			channel->n_rx_xdp_bad_drops++;
			trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act);
		} else {
			channel->n_rx_xdp_redirect++;
		}
		break;

	default:
		bpf_warn_invalid_xdp_action(xdp_act);
		efx_free_rx_buffers(rx_queue, rx_buf, 1);
		channel->n_rx_xdp_bad_drops++;
		trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act);
		break;

	case XDP_ABORTED:
		trace_xdp_exception(efx->net_dev, xdp_prog, xdp_act);
		/* Fall through */
	case XDP_DROP:
		efx_free_rx_buffers(rx_queue, rx_buf, 1);
		channel->n_rx_xdp_drops++;
		break;
	}

	return xdp_act == XDP_PASS;
}

/* Handle a received packet.  Second half: Touches packet payload. */
void __efx_rx_packet(struct efx_channel *channel)
{
	struct efx_nic *efx = channel->efx;
	struct efx_rx_buffer *rx_buf =
		efx_rx_buffer(&channel->rx_queue, channel->rx_pkt_index);
	u8 *eh = efx_rx_buf_va(rx_buf);

	/* Read length from the prefix if necessary.  This already
	 * excludes the length of the prefix itself.
	 */
	if (rx_buf->flags & EFX_RX_PKT_PREFIX_LEN)
		rx_buf->len = le16_to_cpup((__le16 *)
					   (eh + efx->rx_packet_len_offset));

	/* If we're in loopback test, then pass the packet directly to the
	 * loopback layer, and free the rx_buf here
	 */
	if (unlikely(efx->loopback_selftest)) {
		struct efx_rx_queue *rx_queue;

		efx_loopback_rx_packet(efx, eh, rx_buf->len);
		rx_queue = efx_channel_get_rx_queue(channel);
		efx_free_rx_buffers(rx_queue, rx_buf,
				    channel->rx_pkt_n_frags);
		goto out;
	}

	if (!efx_do_xdp(efx, channel, rx_buf, &eh))
		goto out;

	if (unlikely(!(efx->net_dev->features & NETIF_F_RXCSUM)))
		rx_buf->flags &= ~EFX_RX_PKT_CSUMMED;

	if ((rx_buf->flags & EFX_RX_PKT_TCP) && !channel->type->receive_skb)
		efx_rx_packet_gro(channel, rx_buf, channel->rx_pkt_n_frags, eh);
	else
		efx_rx_deliver(channel, eh, rx_buf, channel->rx_pkt_n_frags);
out:
	channel->rx_pkt_n_frags = 0;
}

#ifdef CONFIG_RFS_ACCEL

static void efx_filter_rfs_work(struct work_struct *data)
{
	struct efx_async_filter_insertion *req = container_of(data, struct efx_async_filter_insertion,
							      work);
	struct efx_nic *efx = netdev_priv(req->net_dev);
	struct efx_channel *channel = efx_get_channel(efx, req->rxq_index);
	int slot_idx = req - efx->rps_slot;
	struct efx_arfs_rule *rule;
	u16 arfs_id = 0;
	int rc;

	rc = efx->type->filter_insert(efx, &req->spec, true);
	if (rc >= 0)
		/* Discard 'priority' part of EF10+ filter ID (mcdi_filters) */
		rc %= efx->type->max_rx_ip_filters;
	if (efx->rps_hash_table) {
		spin_lock_bh(&efx->rps_hash_lock);
		rule = efx_rps_hash_find(efx, &req->spec);
		/* The rule might have already gone, if someone else's request
		 * for the same spec was already worked and then expired before
		 * we got around to our work.  In that case we have nothing
		 * tying us to an arfs_id, meaning that as soon as the filter
		 * is considered for expiry it will be removed.
		 */
		if (rule) {
			if (rc < 0)
				rule->filter_id = EFX_ARFS_FILTER_ID_ERROR;
			else
				rule->filter_id = rc;
			arfs_id = rule->arfs_id;
		}
		spin_unlock_bh(&efx->rps_hash_lock);
	}
	if (rc >= 0) {
		/* Remember this so we can check whether to expire the filter
		 * later.
		 */
		mutex_lock(&efx->rps_mutex);
		if (channel->rps_flow_id[rc] == RPS_FLOW_ID_INVALID)
			channel->rfs_filter_count++;
		channel->rps_flow_id[rc] = req->flow_id;
		mutex_unlock(&efx->rps_mutex);

		if (req->spec.ether_type == htons(ETH_P_IP))
			netif_info(efx, rx_status, efx->net_dev,
				   "steering %s %pI4:%u:%pI4:%u to queue %u [flow %u filter %d id %u]\n",
				   (req->spec.ip_proto == IPPROTO_TCP) ? "TCP" : "UDP",
				   req->spec.rem_host, ntohs(req->spec.rem_port),
				   req->spec.loc_host, ntohs(req->spec.loc_port),
				   req->rxq_index, req->flow_id, rc, arfs_id);
		else
			netif_info(efx, rx_status, efx->net_dev,
				   "steering %s [%pI6]:%u:[%pI6]:%u to queue %u [flow %u filter %d id %u]\n",
				   (req->spec.ip_proto == IPPROTO_TCP) ? "TCP" : "UDP",
				   req->spec.rem_host, ntohs(req->spec.rem_port),
				   req->spec.loc_host, ntohs(req->spec.loc_port),
				   req->rxq_index, req->flow_id, rc, arfs_id);
		channel->n_rfs_succeeded++;
	} else {
		if (req->spec.ether_type == htons(ETH_P_IP))
			netif_dbg(efx, rx_status, efx->net_dev,
				  "failed to steer %s %pI4:%u:%pI4:%u to queue %u [flow %u rc %d id %u]\n",
				  (req->spec.ip_proto == IPPROTO_TCP) ? "TCP" : "UDP",
				  req->spec.rem_host, ntohs(req->spec.rem_port),
				  req->spec.loc_host, ntohs(req->spec.loc_port),
				  req->rxq_index, req->flow_id, rc, arfs_id);
		else
			netif_dbg(efx, rx_status, efx->net_dev,
				  "failed to steer %s [%pI6]:%u:[%pI6]:%u to queue %u [flow %u rc %d id %u]\n",
				  (req->spec.ip_proto == IPPROTO_TCP) ? "TCP" : "UDP",
				  req->spec.rem_host, ntohs(req->spec.rem_port),
				  req->spec.loc_host, ntohs(req->spec.loc_port),
				  req->rxq_index, req->flow_id, rc, arfs_id);
		channel->n_rfs_failed++;
		/* We're overloading the NIC's filter tables, so let's do a
		 * chunk of extra expiry work.
		 */
		__efx_filter_rfs_expire(channel, min(channel->rfs_filter_count,
						     100u));
	}

	/* Release references */
	clear_bit(slot_idx, &efx->rps_slot_map);
	dev_put(req->net_dev);
}

int efx_filter_rfs(struct net_device *net_dev, const struct sk_buff *skb,
		   u16 rxq_index, u32 flow_id)
{
	struct efx_nic *efx = netdev_priv(net_dev);
	struct efx_async_filter_insertion *req;
	struct efx_arfs_rule *rule;
	struct flow_keys fk;
	int slot_idx;
	bool new;
	int rc;

	/* find a free slot */
	for (slot_idx = 0; slot_idx < EFX_RPS_MAX_IN_FLIGHT; slot_idx++)
		if (!test_and_set_bit(slot_idx, &efx->rps_slot_map))
			break;
	if (slot_idx >= EFX_RPS_MAX_IN_FLIGHT)
		return -EBUSY;

	if (flow_id == RPS_FLOW_ID_INVALID) {
		rc = -EINVAL;
		goto out_clear;
	}

	if (!skb_flow_dissect_flow_keys(skb, &fk, 0)) {
		rc = -EPROTONOSUPPORT;
		goto out_clear;
	}

	if (fk.basic.n_proto != htons(ETH_P_IP) && fk.basic.n_proto != htons(ETH_P_IPV6)) {
		rc = -EPROTONOSUPPORT;
		goto out_clear;
	}
	if (fk.control.flags & FLOW_DIS_IS_FRAGMENT) {
		rc = -EPROTONOSUPPORT;
		goto out_clear;
	}

	req = efx->rps_slot + slot_idx;
	efx_filter_init_rx(&req->spec, EFX_FILTER_PRI_HINT,
			   efx->rx_scatter ? EFX_FILTER_FLAG_RX_SCATTER : 0,
			   rxq_index);
	req->spec.match_flags =
		EFX_FILTER_MATCH_ETHER_TYPE | EFX_FILTER_MATCH_IP_PROTO |
		EFX_FILTER_MATCH_LOC_HOST | EFX_FILTER_MATCH_LOC_PORT |
		EFX_FILTER_MATCH_REM_HOST | EFX_FILTER_MATCH_REM_PORT;
	req->spec.ether_type = fk.basic.n_proto;
	req->spec.ip_proto = fk.basic.ip_proto;

	if (fk.basic.n_proto == htons(ETH_P_IP)) {
		req->spec.rem_host[0] = fk.addrs.v4addrs.src;
		req->spec.loc_host[0] = fk.addrs.v4addrs.dst;
	} else {
		memcpy(req->spec.rem_host, &fk.addrs.v6addrs.src,
		       sizeof(struct in6_addr));
		memcpy(req->spec.loc_host, &fk.addrs.v6addrs.dst,
		       sizeof(struct in6_addr));
	}

	req->spec.rem_port = fk.ports.src;
	req->spec.loc_port = fk.ports.dst;

	if (efx->rps_hash_table) {
		/* Add it to ARFS hash table */
		spin_lock(&efx->rps_hash_lock);
		rule = efx_rps_hash_add(efx, &req->spec, &new);
		if (!rule) {
			rc = -ENOMEM;
			goto out_unlock;
		}
		if (new)
			rule->arfs_id = efx->rps_next_id++ % RPS_NO_FILTER;
		rc = rule->arfs_id;
		/* Skip if existing or pending filter already does the right thing */
		if (!new && rule->rxq_index == rxq_index &&
		    rule->filter_id >= EFX_ARFS_FILTER_ID_PENDING)
			goto out_unlock;
		rule->rxq_index = rxq_index;
		rule->filter_id = EFX_ARFS_FILTER_ID_PENDING;
		spin_unlock(&efx->rps_hash_lock);
	} else {
		/* Without an ARFS hash table, we just use arfs_id 0 for all
		 * filters.  This means if multiple flows hash to the same
		 * flow_id, all but the most recently touched will be eligible
		 * for expiry.
		 */
		rc = 0;
	}

	/* Queue the request */
	dev_hold(req->net_dev = net_dev);
	INIT_WORK(&req->work, efx_filter_rfs_work);
	req->rxq_index = rxq_index;
	req->flow_id = flow_id;
	schedule_work(&req->work);
	return rc;
out_unlock:
	spin_unlock(&efx->rps_hash_lock);
out_clear:
	clear_bit(slot_idx, &efx->rps_slot_map);
	return rc;
}

bool __efx_filter_rfs_expire(struct efx_channel *channel, unsigned int quota)
{
	bool (*expire_one)(struct efx_nic *efx, u32 flow_id, unsigned int index);
	struct efx_nic *efx = channel->efx;
	unsigned int index, size, start;
	u32 flow_id;

	if (!mutex_trylock(&efx->rps_mutex))
		return false;
	expire_one = efx->type->filter_rfs_expire_one;
	index = channel->rfs_expire_index;
	start = index;
	size = efx->type->max_rx_ip_filters;
	while (quota) {
		flow_id = channel->rps_flow_id[index];

		if (flow_id != RPS_FLOW_ID_INVALID) {
			quota--;
			if (expire_one(efx, flow_id, index)) {
				netif_info(efx, rx_status, efx->net_dev,
					   "expired filter %d [channel %u flow %u]\n",
					   index, channel->channel, flow_id);
				channel->rps_flow_id[index] = RPS_FLOW_ID_INVALID;
				channel->rfs_filter_count--;
			}
		}
		if (++index == size)
			index = 0;
		/* If we were called with a quota that exceeds the total number
		 * of filters in the table (which shouldn't happen, but could
		 * if two callers race), ensure that we don't loop forever -
		 * stop when we've examined every row of the table.
		 */
		if (index == start)
			break;
	}

	channel->rfs_expire_index = index;
	mutex_unlock(&efx->rps_mutex);
	return true;
}

#endif /* CONFIG_RFS_ACCEL */