xref: /linux/drivers/net/ethernet/sfc/rx_common.c (revision 119ff04864a24470b1e531bb53e5c141aa8fefb0)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /****************************************************************************
3  * Driver for Solarflare network controllers and boards
4  * Copyright 2018 Solarflare Communications Inc.
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms of the GNU General Public License version 2 as published
8  * by the Free Software Foundation, incorporated herein by reference.
9  */
10 
11 #include "net_driver.h"
12 #include <linux/module.h>
13 #include <linux/iommu.h>
14 #include "efx.h"
15 #include "nic.h"
16 #include "rx_common.h"
17 
18 /* This is the percentage fill level below which new RX descriptors
19  * will be added to the RX descriptor ring.
20  */
21 static unsigned int rx_refill_threshold;
22 module_param(rx_refill_threshold, uint, 0444);
23 MODULE_PARM_DESC(rx_refill_threshold,
24 		 "RX descriptor ring refill threshold (%)");
25 
26 /* RX maximum head room required.
27  *
28  * This must be at least 1 to prevent overflow, plus one packet-worth
29  * to allow pipelined receives.
30  */
31 #define EFX_RXD_HEAD_ROOM (1 + EFX_RX_MAX_FRAGS)
32 
33 /* Check the RX page recycle ring for a page that can be reused. */
34 static struct page *efx_reuse_page(struct efx_rx_queue *rx_queue)
35 {
36 	struct efx_nic *efx = rx_queue->efx;
37 	struct efx_rx_page_state *state;
38 	unsigned int index;
39 	struct page *page;
40 
41 	if (unlikely(!rx_queue->page_ring))
42 		return NULL;
43 	index = rx_queue->page_remove & rx_queue->page_ptr_mask;
44 	page = rx_queue->page_ring[index];
45 	if (page == NULL)
46 		return NULL;
47 
48 	rx_queue->page_ring[index] = NULL;
49 	/* page_remove cannot exceed page_add. */
50 	if (rx_queue->page_remove != rx_queue->page_add)
51 		++rx_queue->page_remove;
52 
53 	/* If page_count is 1 then we hold the only reference to this page. */
54 	if (page_count(page) == 1) {
55 		++rx_queue->page_recycle_count;
56 		return page;
57 	} else {
58 		state = page_address(page);
59 		dma_unmap_page(&efx->pci_dev->dev, state->dma_addr,
60 			       PAGE_SIZE << efx->rx_buffer_order,
61 			       DMA_FROM_DEVICE);
62 		put_page(page);
63 		++rx_queue->page_recycle_failed;
64 	}
65 
66 	return NULL;
67 }
68 
69 /* Attempt to recycle the page if there is an RX recycle ring; the page can
70  * only be added if this is the final RX buffer, to prevent pages being used in
71  * the descriptor ring and appearing in the recycle ring simultaneously.
72  */
73 static void efx_recycle_rx_page(struct efx_channel *channel,
74 				struct efx_rx_buffer *rx_buf)
75 {
76 	struct efx_rx_queue *rx_queue = efx_channel_get_rx_queue(channel);
77 	struct efx_nic *efx = rx_queue->efx;
78 	struct page *page = rx_buf->page;
79 	unsigned int index;
80 
81 	/* Only recycle the page after processing the final buffer. */
82 	if (!(rx_buf->flags & EFX_RX_BUF_LAST_IN_PAGE))
83 		return;
84 
85 	index = rx_queue->page_add & rx_queue->page_ptr_mask;
86 	if (rx_queue->page_ring[index] == NULL) {
87 		unsigned int read_index = rx_queue->page_remove &
88 			rx_queue->page_ptr_mask;
89 
90 		/* The next slot in the recycle ring is available, but
91 		 * increment page_remove if the read pointer currently
92 		 * points here.
93 		 */
94 		if (read_index == index)
95 			++rx_queue->page_remove;
96 		rx_queue->page_ring[index] = page;
97 		++rx_queue->page_add;
98 		return;
99 	}
100 	++rx_queue->page_recycle_full;
101 	efx_unmap_rx_buffer(efx, rx_buf);
102 	put_page(rx_buf->page);
103 }
104 
105 /* Recycle the pages that are used by buffers that have just been received. */
106 void efx_recycle_rx_pages(struct efx_channel *channel,
107 			  struct efx_rx_buffer *rx_buf,
108 			  unsigned int n_frags)
109 {
110 	struct efx_rx_queue *rx_queue = efx_channel_get_rx_queue(channel);
111 
112 	if (unlikely(!rx_queue->page_ring))
113 		return;
114 
115 	do {
116 		efx_recycle_rx_page(channel, rx_buf);
117 		rx_buf = efx_rx_buf_next(rx_queue, rx_buf);
118 	} while (--n_frags);
119 }
120 
121 void efx_discard_rx_packet(struct efx_channel *channel,
122 			   struct efx_rx_buffer *rx_buf,
123 			   unsigned int n_frags)
124 {
125 	struct efx_rx_queue *rx_queue = efx_channel_get_rx_queue(channel);
126 
127 	efx_recycle_rx_pages(channel, rx_buf, n_frags);
128 
129 	efx_free_rx_buffers(rx_queue, rx_buf, n_frags);
130 }
131 
132 static void efx_init_rx_recycle_ring(struct efx_rx_queue *rx_queue)
133 {
134 	unsigned int bufs_in_recycle_ring, page_ring_size;
135 	struct efx_nic *efx = rx_queue->efx;
136 
137 	bufs_in_recycle_ring = efx_rx_recycle_ring_size(efx);
138 	page_ring_size = roundup_pow_of_two(bufs_in_recycle_ring /
139 					    efx->rx_bufs_per_page);
140 	rx_queue->page_ring = kcalloc(page_ring_size,
141 				      sizeof(*rx_queue->page_ring), GFP_KERNEL);
142 	if (!rx_queue->page_ring)
143 		rx_queue->page_ptr_mask = 0;
144 	else
145 		rx_queue->page_ptr_mask = page_ring_size - 1;
146 }
147 
148 static void efx_fini_rx_recycle_ring(struct efx_rx_queue *rx_queue)
149 {
150 	struct efx_nic *efx = rx_queue->efx;
151 	int i;
152 
153 	if (unlikely(!rx_queue->page_ring))
154 		return;
155 
156 	/* Unmap and release the pages in the recycle ring. Remove the ring. */
157 	for (i = 0; i <= rx_queue->page_ptr_mask; i++) {
158 		struct page *page = rx_queue->page_ring[i];
159 		struct efx_rx_page_state *state;
160 
161 		if (page == NULL)
162 			continue;
163 
164 		state = page_address(page);
165 		dma_unmap_page(&efx->pci_dev->dev, state->dma_addr,
166 			       PAGE_SIZE << efx->rx_buffer_order,
167 			       DMA_FROM_DEVICE);
168 		put_page(page);
169 	}
170 	kfree(rx_queue->page_ring);
171 	rx_queue->page_ring = NULL;
172 }
173 
174 static void efx_fini_rx_buffer(struct efx_rx_queue *rx_queue,
175 			       struct efx_rx_buffer *rx_buf)
176 {
177 	/* Release the page reference we hold for the buffer. */
178 	if (rx_buf->page)
179 		put_page(rx_buf->page);
180 
181 	/* If this is the last buffer in a page, unmap and free it. */
182 	if (rx_buf->flags & EFX_RX_BUF_LAST_IN_PAGE) {
183 		efx_unmap_rx_buffer(rx_queue->efx, rx_buf);
184 		efx_free_rx_buffers(rx_queue, rx_buf, 1);
185 	}
186 	rx_buf->page = NULL;
187 }
188 
189 int efx_probe_rx_queue(struct efx_rx_queue *rx_queue)
190 {
191 	struct efx_nic *efx = rx_queue->efx;
192 	unsigned int entries;
193 	int rc;
194 
195 	/* Create the smallest power-of-two aligned ring */
196 	entries = max(roundup_pow_of_two(efx->rxq_entries), EFX_MIN_DMAQ_SIZE);
197 	EFX_WARN_ON_PARANOID(entries > EFX_MAX_DMAQ_SIZE);
198 	rx_queue->ptr_mask = entries - 1;
199 
200 	netif_dbg(efx, probe, efx->net_dev,
201 		  "creating RX queue %d size %#x mask %#x\n",
202 		  efx_rx_queue_index(rx_queue), efx->rxq_entries,
203 		  rx_queue->ptr_mask);
204 
205 	/* Allocate RX buffers */
206 	rx_queue->buffer = kcalloc(entries, sizeof(*rx_queue->buffer),
207 				   GFP_KERNEL);
208 	if (!rx_queue->buffer)
209 		return -ENOMEM;
210 
211 	rc = efx_nic_probe_rx(rx_queue);
212 	if (rc) {
213 		kfree(rx_queue->buffer);
214 		rx_queue->buffer = NULL;
215 	}
216 
217 	return rc;
218 }
219 
220 void efx_init_rx_queue(struct efx_rx_queue *rx_queue)
221 {
222 	unsigned int max_fill, trigger, max_trigger;
223 	struct efx_nic *efx = rx_queue->efx;
224 	int rc = 0;
225 
226 	netif_dbg(rx_queue->efx, drv, rx_queue->efx->net_dev,
227 		  "initialising RX queue %d\n", efx_rx_queue_index(rx_queue));
228 
229 	/* Initialise ptr fields */
230 	rx_queue->added_count = 0;
231 	rx_queue->notified_count = 0;
232 	rx_queue->granted_count = 0;
233 	rx_queue->removed_count = 0;
234 	rx_queue->min_fill = -1U;
235 	efx_init_rx_recycle_ring(rx_queue);
236 
237 	rx_queue->page_remove = 0;
238 	rx_queue->page_add = rx_queue->page_ptr_mask + 1;
239 	rx_queue->page_recycle_count = 0;
240 	rx_queue->page_recycle_failed = 0;
241 	rx_queue->page_recycle_full = 0;
242 
243 	/* Initialise limit fields */
244 	max_fill = efx->rxq_entries - EFX_RXD_HEAD_ROOM;
245 	max_trigger =
246 		max_fill - efx->rx_pages_per_batch * efx->rx_bufs_per_page;
247 	if (rx_refill_threshold != 0) {
248 		trigger = max_fill * min(rx_refill_threshold, 100U) / 100U;
249 		if (trigger > max_trigger)
250 			trigger = max_trigger;
251 	} else {
252 		trigger = max_trigger;
253 	}
254 
255 	rx_queue->max_fill = max_fill;
256 	rx_queue->fast_fill_trigger = trigger;
257 	rx_queue->refill_enabled = true;
258 
259 	/* Initialise XDP queue information */
260 	rc = xdp_rxq_info_reg(&rx_queue->xdp_rxq_info, efx->net_dev,
261 			      rx_queue->core_index, 0);
262 
263 	if (rc) {
264 		netif_err(efx, rx_err, efx->net_dev,
265 			  "Failure to initialise XDP queue information rc=%d\n",
266 			  rc);
267 		efx->xdp_rxq_info_failed = true;
268 	} else {
269 		rx_queue->xdp_rxq_info_valid = true;
270 	}
271 
272 	/* Set up RX descriptor ring */
273 	efx_nic_init_rx(rx_queue);
274 }
275 
276 void efx_fini_rx_queue(struct efx_rx_queue *rx_queue)
277 {
278 	struct efx_rx_buffer *rx_buf;
279 	int i;
280 
281 	netif_dbg(rx_queue->efx, drv, rx_queue->efx->net_dev,
282 		  "shutting down RX queue %d\n", efx_rx_queue_index(rx_queue));
283 
284 	del_timer_sync(&rx_queue->slow_fill);
285 	if (rx_queue->grant_credits)
286 		flush_work(&rx_queue->grant_work);
287 
288 	/* Release RX buffers from the current read ptr to the write ptr */
289 	if (rx_queue->buffer) {
290 		for (i = rx_queue->removed_count; i < rx_queue->added_count;
291 		     i++) {
292 			unsigned int index = i & rx_queue->ptr_mask;
293 
294 			rx_buf = efx_rx_buffer(rx_queue, index);
295 			efx_fini_rx_buffer(rx_queue, rx_buf);
296 		}
297 	}
298 
299 	efx_fini_rx_recycle_ring(rx_queue);
300 
301 	if (rx_queue->xdp_rxq_info_valid)
302 		xdp_rxq_info_unreg(&rx_queue->xdp_rxq_info);
303 
304 	rx_queue->xdp_rxq_info_valid = false;
305 }
306 
307 void efx_remove_rx_queue(struct efx_rx_queue *rx_queue)
308 {
309 	netif_dbg(rx_queue->efx, drv, rx_queue->efx->net_dev,
310 		  "destroying RX queue %d\n", efx_rx_queue_index(rx_queue));
311 
312 	efx_nic_remove_rx(rx_queue);
313 
314 	kfree(rx_queue->buffer);
315 	rx_queue->buffer = NULL;
316 }
317 
318 /* Unmap a DMA-mapped page.  This function is only called for the final RX
319  * buffer in a page.
320  */
321 void efx_unmap_rx_buffer(struct efx_nic *efx,
322 			 struct efx_rx_buffer *rx_buf)
323 {
324 	struct page *page = rx_buf->page;
325 
326 	if (page) {
327 		struct efx_rx_page_state *state = page_address(page);
328 
329 		dma_unmap_page(&efx->pci_dev->dev,
330 			       state->dma_addr,
331 			       PAGE_SIZE << efx->rx_buffer_order,
332 			       DMA_FROM_DEVICE);
333 	}
334 }
335 
336 void efx_free_rx_buffers(struct efx_rx_queue *rx_queue,
337 			 struct efx_rx_buffer *rx_buf,
338 			 unsigned int num_bufs)
339 {
340 	do {
341 		if (rx_buf->page) {
342 			put_page(rx_buf->page);
343 			rx_buf->page = NULL;
344 		}
345 		rx_buf = efx_rx_buf_next(rx_queue, rx_buf);
346 	} while (--num_bufs);
347 }
348 
349 void efx_rx_slow_fill(struct timer_list *t)
350 {
351 	struct efx_rx_queue *rx_queue = from_timer(rx_queue, t, slow_fill);
352 
353 	/* Post an event to cause NAPI to run and refill the queue */
354 	efx_nic_generate_fill_event(rx_queue);
355 	++rx_queue->slow_fill_count;
356 }
357 
358 void efx_schedule_slow_fill(struct efx_rx_queue *rx_queue)
359 {
360 	mod_timer(&rx_queue->slow_fill, jiffies + msecs_to_jiffies(10));
361 }
362 
363 /* efx_init_rx_buffers - create EFX_RX_BATCH page-based RX buffers
364  *
365  * @rx_queue:		Efx RX queue
366  *
367  * This allocates a batch of pages, maps them for DMA, and populates
368  * struct efx_rx_buffers for each one. Return a negative error code or
369  * 0 on success. If a single page can be used for multiple buffers,
370  * then the page will either be inserted fully, or not at all.
371  */
372 static int efx_init_rx_buffers(struct efx_rx_queue *rx_queue, bool atomic)
373 {
374 	unsigned int page_offset, index, count;
375 	struct efx_nic *efx = rx_queue->efx;
376 	struct efx_rx_page_state *state;
377 	struct efx_rx_buffer *rx_buf;
378 	dma_addr_t dma_addr;
379 	struct page *page;
380 
381 	count = 0;
382 	do {
383 		page = efx_reuse_page(rx_queue);
384 		if (page == NULL) {
385 			page = alloc_pages(__GFP_COMP |
386 					   (atomic ? GFP_ATOMIC : GFP_KERNEL),
387 					   efx->rx_buffer_order);
388 			if (unlikely(page == NULL))
389 				return -ENOMEM;
390 			dma_addr =
391 				dma_map_page(&efx->pci_dev->dev, page, 0,
392 					     PAGE_SIZE << efx->rx_buffer_order,
393 					     DMA_FROM_DEVICE);
394 			if (unlikely(dma_mapping_error(&efx->pci_dev->dev,
395 						       dma_addr))) {
396 				__free_pages(page, efx->rx_buffer_order);
397 				return -EIO;
398 			}
399 			state = page_address(page);
400 			state->dma_addr = dma_addr;
401 		} else {
402 			state = page_address(page);
403 			dma_addr = state->dma_addr;
404 		}
405 
406 		dma_addr += sizeof(struct efx_rx_page_state);
407 		page_offset = sizeof(struct efx_rx_page_state);
408 
409 		do {
410 			index = rx_queue->added_count & rx_queue->ptr_mask;
411 			rx_buf = efx_rx_buffer(rx_queue, index);
412 			rx_buf->dma_addr = dma_addr + efx->rx_ip_align +
413 					   EFX_XDP_HEADROOM;
414 			rx_buf->page = page;
415 			rx_buf->page_offset = page_offset + efx->rx_ip_align +
416 					      EFX_XDP_HEADROOM;
417 			rx_buf->len = efx->rx_dma_len;
418 			rx_buf->flags = 0;
419 			++rx_queue->added_count;
420 			get_page(page);
421 			dma_addr += efx->rx_page_buf_step;
422 			page_offset += efx->rx_page_buf_step;
423 		} while (page_offset + efx->rx_page_buf_step <= PAGE_SIZE);
424 
425 		rx_buf->flags = EFX_RX_BUF_LAST_IN_PAGE;
426 	} while (++count < efx->rx_pages_per_batch);
427 
428 	return 0;
429 }
430 
431 void efx_rx_config_page_split(struct efx_nic *efx)
432 {
433 	efx->rx_page_buf_step = ALIGN(efx->rx_dma_len + efx->rx_ip_align +
434 				      EFX_XDP_HEADROOM + EFX_XDP_TAILROOM,
435 				      EFX_RX_BUF_ALIGNMENT);
436 	efx->rx_bufs_per_page = efx->rx_buffer_order ? 1 :
437 		((PAGE_SIZE - sizeof(struct efx_rx_page_state)) /
438 		efx->rx_page_buf_step);
439 	efx->rx_buffer_truesize = (PAGE_SIZE << efx->rx_buffer_order) /
440 		efx->rx_bufs_per_page;
441 	efx->rx_pages_per_batch = DIV_ROUND_UP(EFX_RX_PREFERRED_BATCH,
442 					       efx->rx_bufs_per_page);
443 }
444 
445 /* efx_fast_push_rx_descriptors - push new RX descriptors quickly
446  * @rx_queue:		RX descriptor queue
447  *
448  * This will aim to fill the RX descriptor queue up to
449  * @rx_queue->@max_fill. If there is insufficient atomic
450  * memory to do so, a slow fill will be scheduled.
451  *
452  * The caller must provide serialisation (none is used here). In practise,
453  * this means this function must run from the NAPI handler, or be called
454  * when NAPI is disabled.
455  */
456 void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue, bool atomic)
457 {
458 	struct efx_nic *efx = rx_queue->efx;
459 	unsigned int fill_level, batch_size;
460 	int space, rc = 0;
461 
462 	if (!rx_queue->refill_enabled)
463 		return;
464 
465 	/* Calculate current fill level, and exit if we don't need to fill */
466 	fill_level = (rx_queue->added_count - rx_queue->removed_count);
467 	EFX_WARN_ON_ONCE_PARANOID(fill_level > rx_queue->efx->rxq_entries);
468 	if (fill_level >= rx_queue->fast_fill_trigger)
469 		goto out;
470 
471 	/* Record minimum fill level */
472 	if (unlikely(fill_level < rx_queue->min_fill)) {
473 		if (fill_level)
474 			rx_queue->min_fill = fill_level;
475 	}
476 
477 	batch_size = efx->rx_pages_per_batch * efx->rx_bufs_per_page;
478 	space = rx_queue->max_fill - fill_level;
479 	EFX_WARN_ON_ONCE_PARANOID(space < batch_size);
480 
481 	netif_vdbg(rx_queue->efx, rx_status, rx_queue->efx->net_dev,
482 		   "RX queue %d fast-filling descriptor ring from"
483 		   " level %d to level %d\n",
484 		   efx_rx_queue_index(rx_queue), fill_level,
485 		   rx_queue->max_fill);
486 
487 	do {
488 		rc = efx_init_rx_buffers(rx_queue, atomic);
489 		if (unlikely(rc)) {
490 			/* Ensure that we don't leave the rx queue empty */
491 			efx_schedule_slow_fill(rx_queue);
492 			goto out;
493 		}
494 	} while ((space -= batch_size) >= batch_size);
495 
496 	netif_vdbg(rx_queue->efx, rx_status, rx_queue->efx->net_dev,
497 		   "RX queue %d fast-filled descriptor ring "
498 		   "to level %d\n", efx_rx_queue_index(rx_queue),
499 		   rx_queue->added_count - rx_queue->removed_count);
500 
501  out:
502 	if (rx_queue->notified_count != rx_queue->added_count)
503 		efx_nic_notify_rx_desc(rx_queue);
504 }
505 
506 /* Pass a received packet up through GRO.  GRO can handle pages
507  * regardless of checksum state and skbs with a good checksum.
508  */
509 void
510 efx_rx_packet_gro(struct efx_channel *channel, struct efx_rx_buffer *rx_buf,
511 		  unsigned int n_frags, u8 *eh, __wsum csum)
512 {
513 	struct napi_struct *napi = &channel->napi_str;
514 	struct efx_nic *efx = channel->efx;
515 	struct sk_buff *skb;
516 
517 	skb = napi_get_frags(napi);
518 	if (unlikely(!skb)) {
519 		struct efx_rx_queue *rx_queue;
520 
521 		rx_queue = efx_channel_get_rx_queue(channel);
522 		efx_free_rx_buffers(rx_queue, rx_buf, n_frags);
523 		return;
524 	}
525 
526 	if (efx->net_dev->features & NETIF_F_RXHASH &&
527 	    efx_rx_buf_hash_valid(efx, eh))
528 		skb_set_hash(skb, efx_rx_buf_hash(efx, eh),
529 			     PKT_HASH_TYPE_L3);
530 	if (csum) {
531 		skb->csum = csum;
532 		skb->ip_summed = CHECKSUM_COMPLETE;
533 	} else {
534 		skb->ip_summed = ((rx_buf->flags & EFX_RX_PKT_CSUMMED) ?
535 				  CHECKSUM_UNNECESSARY : CHECKSUM_NONE);
536 	}
537 	skb->csum_level = !!(rx_buf->flags & EFX_RX_PKT_CSUM_LEVEL);
538 
539 	for (;;) {
540 		skb_fill_page_desc(skb, skb_shinfo(skb)->nr_frags,
541 				   rx_buf->page, rx_buf->page_offset,
542 				   rx_buf->len);
543 		rx_buf->page = NULL;
544 		skb->len += rx_buf->len;
545 		if (skb_shinfo(skb)->nr_frags == n_frags)
546 			break;
547 
548 		rx_buf = efx_rx_buf_next(&channel->rx_queue, rx_buf);
549 	}
550 
551 	skb->data_len = skb->len;
552 	skb->truesize += n_frags * efx->rx_buffer_truesize;
553 
554 	skb_record_rx_queue(skb, channel->rx_queue.core_index);
555 
556 	napi_gro_frags(napi);
557 }
558 
559 /* RSS contexts.  We're using linked lists and crappy O(n) algorithms, because
560  * (a) this is an infrequent control-plane operation and (b) n is small (max 64)
561  */
562 struct efx_rss_context *efx_alloc_rss_context_entry(struct efx_nic *efx)
563 {
564 	struct list_head *head = &efx->rss_context.list;
565 	struct efx_rss_context *ctx, *new;
566 	u32 id = 1; /* Don't use zero, that refers to the master RSS context */
567 
568 	WARN_ON(!mutex_is_locked(&efx->rss_lock));
569 
570 	/* Search for first gap in the numbering */
571 	list_for_each_entry(ctx, head, list) {
572 		if (ctx->user_id != id)
573 			break;
574 		id++;
575 		/* Check for wrap.  If this happens, we have nearly 2^32
576 		 * allocated RSS contexts, which seems unlikely.
577 		 */
578 		if (WARN_ON_ONCE(!id))
579 			return NULL;
580 	}
581 
582 	/* Create the new entry */
583 	new = kmalloc(sizeof(*new), GFP_KERNEL);
584 	if (!new)
585 		return NULL;
586 	new->context_id = EFX_MCDI_RSS_CONTEXT_INVALID;
587 	new->rx_hash_udp_4tuple = false;
588 
589 	/* Insert the new entry into the gap */
590 	new->user_id = id;
591 	list_add_tail(&new->list, &ctx->list);
592 	return new;
593 }
594 
595 struct efx_rss_context *efx_find_rss_context_entry(struct efx_nic *efx, u32 id)
596 {
597 	struct list_head *head = &efx->rss_context.list;
598 	struct efx_rss_context *ctx;
599 
600 	WARN_ON(!mutex_is_locked(&efx->rss_lock));
601 
602 	list_for_each_entry(ctx, head, list)
603 		if (ctx->user_id == id)
604 			return ctx;
605 	return NULL;
606 }
607 
608 void efx_free_rss_context_entry(struct efx_rss_context *ctx)
609 {
610 	list_del(&ctx->list);
611 	kfree(ctx);
612 }
613 
614 void efx_set_default_rx_indir_table(struct efx_nic *efx,
615 				    struct efx_rss_context *ctx)
616 {
617 	size_t i;
618 
619 	for (i = 0; i < ARRAY_SIZE(ctx->rx_indir_table); i++)
620 		ctx->rx_indir_table[i] =
621 			ethtool_rxfh_indir_default(i, efx->rss_spread);
622 }
623 
624 /**
625  * efx_filter_is_mc_recipient - test whether spec is a multicast recipient
626  * @spec: Specification to test
627  *
628  * Return: %true if the specification is a non-drop RX filter that
629  * matches a local MAC address I/G bit value of 1 or matches a local
630  * IPv4 or IPv6 address value in the respective multicast address
631  * range.  Otherwise %false.
632  */
633 bool efx_filter_is_mc_recipient(const struct efx_filter_spec *spec)
634 {
635 	if (!(spec->flags & EFX_FILTER_FLAG_RX) ||
636 	    spec->dmaq_id == EFX_FILTER_RX_DMAQ_ID_DROP)
637 		return false;
638 
639 	if (spec->match_flags &
640 	    (EFX_FILTER_MATCH_LOC_MAC | EFX_FILTER_MATCH_LOC_MAC_IG) &&
641 	    is_multicast_ether_addr(spec->loc_mac))
642 		return true;
643 
644 	if ((spec->match_flags &
645 	     (EFX_FILTER_MATCH_ETHER_TYPE | EFX_FILTER_MATCH_LOC_HOST)) ==
646 	    (EFX_FILTER_MATCH_ETHER_TYPE | EFX_FILTER_MATCH_LOC_HOST)) {
647 		if (spec->ether_type == htons(ETH_P_IP) &&
648 		    ipv4_is_multicast(spec->loc_host[0]))
649 			return true;
650 		if (spec->ether_type == htons(ETH_P_IPV6) &&
651 		    ((const u8 *)spec->loc_host)[0] == 0xff)
652 			return true;
653 	}
654 
655 	return false;
656 }
657 
658 bool efx_filter_spec_equal(const struct efx_filter_spec *left,
659 			   const struct efx_filter_spec *right)
660 {
661 	if ((left->match_flags ^ right->match_flags) |
662 	    ((left->flags ^ right->flags) &
663 	     (EFX_FILTER_FLAG_RX | EFX_FILTER_FLAG_TX)))
664 		return false;
665 
666 	return memcmp(&left->vport_id, &right->vport_id,
667 		      sizeof(struct efx_filter_spec) -
668 		      offsetof(struct efx_filter_spec, vport_id)) == 0;
669 }
670 
671 u32 efx_filter_spec_hash(const struct efx_filter_spec *spec)
672 {
673 	BUILD_BUG_ON(offsetof(struct efx_filter_spec, vport_id) & 3);
674 	return jhash2((const u32 *)&spec->vport_id,
675 		      (sizeof(struct efx_filter_spec) -
676 		       offsetof(struct efx_filter_spec, vport_id)) / 4,
677 		      0);
678 }
679 
680 #ifdef CONFIG_RFS_ACCEL
681 bool efx_rps_check_rule(struct efx_arfs_rule *rule, unsigned int filter_idx,
682 			bool *force)
683 {
684 	if (rule->filter_id == EFX_ARFS_FILTER_ID_PENDING) {
685 		/* ARFS is currently updating this entry, leave it */
686 		return false;
687 	}
688 	if (rule->filter_id == EFX_ARFS_FILTER_ID_ERROR) {
689 		/* ARFS tried and failed to update this, so it's probably out
690 		 * of date.  Remove the filter and the ARFS rule entry.
691 		 */
692 		rule->filter_id = EFX_ARFS_FILTER_ID_REMOVING;
693 		*force = true;
694 		return true;
695 	} else if (WARN_ON(rule->filter_id != filter_idx)) { /* can't happen */
696 		/* ARFS has moved on, so old filter is not needed.  Since we did
697 		 * not mark the rule with EFX_ARFS_FILTER_ID_REMOVING, it will
698 		 * not be removed by efx_rps_hash_del() subsequently.
699 		 */
700 		*force = true;
701 		return true;
702 	}
703 	/* Remove it iff ARFS wants to. */
704 	return true;
705 }
706 
707 static
708 struct hlist_head *efx_rps_hash_bucket(struct efx_nic *efx,
709 				       const struct efx_filter_spec *spec)
710 {
711 	u32 hash = efx_filter_spec_hash(spec);
712 
713 	lockdep_assert_held(&efx->rps_hash_lock);
714 	if (!efx->rps_hash_table)
715 		return NULL;
716 	return &efx->rps_hash_table[hash % EFX_ARFS_HASH_TABLE_SIZE];
717 }
718 
719 struct efx_arfs_rule *efx_rps_hash_find(struct efx_nic *efx,
720 					const struct efx_filter_spec *spec)
721 {
722 	struct efx_arfs_rule *rule;
723 	struct hlist_head *head;
724 	struct hlist_node *node;
725 
726 	head = efx_rps_hash_bucket(efx, spec);
727 	if (!head)
728 		return NULL;
729 	hlist_for_each(node, head) {
730 		rule = container_of(node, struct efx_arfs_rule, node);
731 		if (efx_filter_spec_equal(spec, &rule->spec))
732 			return rule;
733 	}
734 	return NULL;
735 }
736 
737 struct efx_arfs_rule *efx_rps_hash_add(struct efx_nic *efx,
738 				       const struct efx_filter_spec *spec,
739 				       bool *new)
740 {
741 	struct efx_arfs_rule *rule;
742 	struct hlist_head *head;
743 	struct hlist_node *node;
744 
745 	head = efx_rps_hash_bucket(efx, spec);
746 	if (!head)
747 		return NULL;
748 	hlist_for_each(node, head) {
749 		rule = container_of(node, struct efx_arfs_rule, node);
750 		if (efx_filter_spec_equal(spec, &rule->spec)) {
751 			*new = false;
752 			return rule;
753 		}
754 	}
755 	rule = kmalloc(sizeof(*rule), GFP_ATOMIC);
756 	*new = true;
757 	if (rule) {
758 		memcpy(&rule->spec, spec, sizeof(rule->spec));
759 		hlist_add_head(&rule->node, head);
760 	}
761 	return rule;
762 }
763 
764 void efx_rps_hash_del(struct efx_nic *efx, const struct efx_filter_spec *spec)
765 {
766 	struct efx_arfs_rule *rule;
767 	struct hlist_head *head;
768 	struct hlist_node *node;
769 
770 	head = efx_rps_hash_bucket(efx, spec);
771 	if (WARN_ON(!head))
772 		return;
773 	hlist_for_each(node, head) {
774 		rule = container_of(node, struct efx_arfs_rule, node);
775 		if (efx_filter_spec_equal(spec, &rule->spec)) {
776 			/* Someone already reused the entry.  We know that if
777 			 * this check doesn't fire (i.e. filter_id == REMOVING)
778 			 * then the REMOVING mark was put there by our caller,
779 			 * because caller is holding a lock on filter table and
780 			 * only holders of that lock set REMOVING.
781 			 */
782 			if (rule->filter_id != EFX_ARFS_FILTER_ID_REMOVING)
783 				return;
784 			hlist_del(node);
785 			kfree(rule);
786 			return;
787 		}
788 	}
789 	/* We didn't find it. */
790 	WARN_ON(1);
791 }
792 #endif
793 
794 int efx_probe_filters(struct efx_nic *efx)
795 {
796 	int rc;
797 
798 	mutex_lock(&efx->mac_lock);
799 	rc = efx->type->filter_table_probe(efx);
800 	if (rc)
801 		goto out_unlock;
802 
803 #ifdef CONFIG_RFS_ACCEL
804 	if (efx->type->offload_features & NETIF_F_NTUPLE) {
805 		struct efx_channel *channel;
806 		int i, success = 1;
807 
808 		efx_for_each_channel(channel, efx) {
809 			channel->rps_flow_id =
810 				kcalloc(efx->type->max_rx_ip_filters,
811 					sizeof(*channel->rps_flow_id),
812 					GFP_KERNEL);
813 			if (!channel->rps_flow_id)
814 				success = 0;
815 			else
816 				for (i = 0;
817 				     i < efx->type->max_rx_ip_filters;
818 				     ++i)
819 					channel->rps_flow_id[i] =
820 						RPS_FLOW_ID_INVALID;
821 			channel->rfs_expire_index = 0;
822 			channel->rfs_filter_count = 0;
823 		}
824 
825 		if (!success) {
826 			efx_for_each_channel(channel, efx) {
827 				kfree(channel->rps_flow_id);
828 				channel->rps_flow_id = NULL;
829 			}
830 			efx->type->filter_table_remove(efx);
831 			rc = -ENOMEM;
832 			goto out_unlock;
833 		}
834 	}
835 #endif
836 out_unlock:
837 	mutex_unlock(&efx->mac_lock);
838 	return rc;
839 }
840 
841 void efx_remove_filters(struct efx_nic *efx)
842 {
843 #ifdef CONFIG_RFS_ACCEL
844 	struct efx_channel *channel;
845 
846 	efx_for_each_channel(channel, efx) {
847 		cancel_delayed_work_sync(&channel->filter_work);
848 		kfree(channel->rps_flow_id);
849 		channel->rps_flow_id = NULL;
850 	}
851 #endif
852 	efx->type->filter_table_remove(efx);
853 }
854 
855 #ifdef CONFIG_RFS_ACCEL
856 
857 static void efx_filter_rfs_work(struct work_struct *data)
858 {
859 	struct efx_async_filter_insertion *req = container_of(data, struct efx_async_filter_insertion,
860 							      work);
861 	struct efx_nic *efx = efx_netdev_priv(req->net_dev);
862 	struct efx_channel *channel = efx_get_channel(efx, req->rxq_index);
863 	int slot_idx = req - efx->rps_slot;
864 	struct efx_arfs_rule *rule;
865 	u16 arfs_id = 0;
866 	int rc;
867 
868 	rc = efx->type->filter_insert(efx, &req->spec, true);
869 	if (rc >= 0)
870 		/* Discard 'priority' part of EF10+ filter ID (mcdi_filters) */
871 		rc %= efx->type->max_rx_ip_filters;
872 	if (efx->rps_hash_table) {
873 		spin_lock_bh(&efx->rps_hash_lock);
874 		rule = efx_rps_hash_find(efx, &req->spec);
875 		/* The rule might have already gone, if someone else's request
876 		 * for the same spec was already worked and then expired before
877 		 * we got around to our work.  In that case we have nothing
878 		 * tying us to an arfs_id, meaning that as soon as the filter
879 		 * is considered for expiry it will be removed.
880 		 */
881 		if (rule) {
882 			if (rc < 0)
883 				rule->filter_id = EFX_ARFS_FILTER_ID_ERROR;
884 			else
885 				rule->filter_id = rc;
886 			arfs_id = rule->arfs_id;
887 		}
888 		spin_unlock_bh(&efx->rps_hash_lock);
889 	}
890 	if (rc >= 0) {
891 		/* Remember this so we can check whether to expire the filter
892 		 * later.
893 		 */
894 		mutex_lock(&efx->rps_mutex);
895 		if (channel->rps_flow_id[rc] == RPS_FLOW_ID_INVALID)
896 			channel->rfs_filter_count++;
897 		channel->rps_flow_id[rc] = req->flow_id;
898 		mutex_unlock(&efx->rps_mutex);
899 
900 		if (req->spec.ether_type == htons(ETH_P_IP))
901 			netif_info(efx, rx_status, efx->net_dev,
902 				   "steering %s %pI4:%u:%pI4:%u to queue %u [flow %u filter %d id %u]\n",
903 				   (req->spec.ip_proto == IPPROTO_TCP) ? "TCP" : "UDP",
904 				   req->spec.rem_host, ntohs(req->spec.rem_port),
905 				   req->spec.loc_host, ntohs(req->spec.loc_port),
906 				   req->rxq_index, req->flow_id, rc, arfs_id);
907 		else
908 			netif_info(efx, rx_status, efx->net_dev,
909 				   "steering %s [%pI6]:%u:[%pI6]:%u to queue %u [flow %u filter %d id %u]\n",
910 				   (req->spec.ip_proto == IPPROTO_TCP) ? "TCP" : "UDP",
911 				   req->spec.rem_host, ntohs(req->spec.rem_port),
912 				   req->spec.loc_host, ntohs(req->spec.loc_port),
913 				   req->rxq_index, req->flow_id, rc, arfs_id);
914 		channel->n_rfs_succeeded++;
915 	} else {
916 		if (req->spec.ether_type == htons(ETH_P_IP))
917 			netif_dbg(efx, rx_status, efx->net_dev,
918 				  "failed to steer %s %pI4:%u:%pI4:%u to queue %u [flow %u rc %d id %u]\n",
919 				  (req->spec.ip_proto == IPPROTO_TCP) ? "TCP" : "UDP",
920 				  req->spec.rem_host, ntohs(req->spec.rem_port),
921 				  req->spec.loc_host, ntohs(req->spec.loc_port),
922 				  req->rxq_index, req->flow_id, rc, arfs_id);
923 		else
924 			netif_dbg(efx, rx_status, efx->net_dev,
925 				  "failed to steer %s [%pI6]:%u:[%pI6]:%u to queue %u [flow %u rc %d id %u]\n",
926 				  (req->spec.ip_proto == IPPROTO_TCP) ? "TCP" : "UDP",
927 				  req->spec.rem_host, ntohs(req->spec.rem_port),
928 				  req->spec.loc_host, ntohs(req->spec.loc_port),
929 				  req->rxq_index, req->flow_id, rc, arfs_id);
930 		channel->n_rfs_failed++;
931 		/* We're overloading the NIC's filter tables, so let's do a
932 		 * chunk of extra expiry work.
933 		 */
934 		__efx_filter_rfs_expire(channel, min(channel->rfs_filter_count,
935 						     100u));
936 	}
937 
938 	/* Release references */
939 	clear_bit(slot_idx, &efx->rps_slot_map);
940 	dev_put(req->net_dev);
941 }
942 
943 int efx_filter_rfs(struct net_device *net_dev, const struct sk_buff *skb,
944 		   u16 rxq_index, u32 flow_id)
945 {
946 	struct efx_nic *efx = efx_netdev_priv(net_dev);
947 	struct efx_async_filter_insertion *req;
948 	struct efx_arfs_rule *rule;
949 	struct flow_keys fk;
950 	int slot_idx;
951 	bool new;
952 	int rc;
953 
954 	/* find a free slot */
955 	for (slot_idx = 0; slot_idx < EFX_RPS_MAX_IN_FLIGHT; slot_idx++)
956 		if (!test_and_set_bit(slot_idx, &efx->rps_slot_map))
957 			break;
958 	if (slot_idx >= EFX_RPS_MAX_IN_FLIGHT)
959 		return -EBUSY;
960 
961 	if (flow_id == RPS_FLOW_ID_INVALID) {
962 		rc = -EINVAL;
963 		goto out_clear;
964 	}
965 
966 	if (!skb_flow_dissect_flow_keys(skb, &fk, 0)) {
967 		rc = -EPROTONOSUPPORT;
968 		goto out_clear;
969 	}
970 
971 	if (fk.basic.n_proto != htons(ETH_P_IP) && fk.basic.n_proto != htons(ETH_P_IPV6)) {
972 		rc = -EPROTONOSUPPORT;
973 		goto out_clear;
974 	}
975 	if (fk.control.flags & FLOW_DIS_IS_FRAGMENT) {
976 		rc = -EPROTONOSUPPORT;
977 		goto out_clear;
978 	}
979 
980 	req = efx->rps_slot + slot_idx;
981 	efx_filter_init_rx(&req->spec, EFX_FILTER_PRI_HINT,
982 			   efx->rx_scatter ? EFX_FILTER_FLAG_RX_SCATTER : 0,
983 			   rxq_index);
984 	req->spec.match_flags =
985 		EFX_FILTER_MATCH_ETHER_TYPE | EFX_FILTER_MATCH_IP_PROTO |
986 		EFX_FILTER_MATCH_LOC_HOST | EFX_FILTER_MATCH_LOC_PORT |
987 		EFX_FILTER_MATCH_REM_HOST | EFX_FILTER_MATCH_REM_PORT;
988 	req->spec.ether_type = fk.basic.n_proto;
989 	req->spec.ip_proto = fk.basic.ip_proto;
990 
991 	if (fk.basic.n_proto == htons(ETH_P_IP)) {
992 		req->spec.rem_host[0] = fk.addrs.v4addrs.src;
993 		req->spec.loc_host[0] = fk.addrs.v4addrs.dst;
994 	} else {
995 		memcpy(req->spec.rem_host, &fk.addrs.v6addrs.src,
996 		       sizeof(struct in6_addr));
997 		memcpy(req->spec.loc_host, &fk.addrs.v6addrs.dst,
998 		       sizeof(struct in6_addr));
999 	}
1000 
1001 	req->spec.rem_port = fk.ports.src;
1002 	req->spec.loc_port = fk.ports.dst;
1003 
1004 	if (efx->rps_hash_table) {
1005 		/* Add it to ARFS hash table */
1006 		spin_lock(&efx->rps_hash_lock);
1007 		rule = efx_rps_hash_add(efx, &req->spec, &new);
1008 		if (!rule) {
1009 			rc = -ENOMEM;
1010 			goto out_unlock;
1011 		}
1012 		if (new)
1013 			rule->arfs_id = efx->rps_next_id++ % RPS_NO_FILTER;
1014 		rc = rule->arfs_id;
1015 		/* Skip if existing or pending filter already does the right thing */
1016 		if (!new && rule->rxq_index == rxq_index &&
1017 		    rule->filter_id >= EFX_ARFS_FILTER_ID_PENDING)
1018 			goto out_unlock;
1019 		rule->rxq_index = rxq_index;
1020 		rule->filter_id = EFX_ARFS_FILTER_ID_PENDING;
1021 		spin_unlock(&efx->rps_hash_lock);
1022 	} else {
1023 		/* Without an ARFS hash table, we just use arfs_id 0 for all
1024 		 * filters.  This means if multiple flows hash to the same
1025 		 * flow_id, all but the most recently touched will be eligible
1026 		 * for expiry.
1027 		 */
1028 		rc = 0;
1029 	}
1030 
1031 	/* Queue the request */
1032 	dev_hold(req->net_dev = net_dev);
1033 	INIT_WORK(&req->work, efx_filter_rfs_work);
1034 	req->rxq_index = rxq_index;
1035 	req->flow_id = flow_id;
1036 	schedule_work(&req->work);
1037 	return rc;
1038 out_unlock:
1039 	spin_unlock(&efx->rps_hash_lock);
1040 out_clear:
1041 	clear_bit(slot_idx, &efx->rps_slot_map);
1042 	return rc;
1043 }
1044 
1045 bool __efx_filter_rfs_expire(struct efx_channel *channel, unsigned int quota)
1046 {
1047 	bool (*expire_one)(struct efx_nic *efx, u32 flow_id, unsigned int index);
1048 	struct efx_nic *efx = channel->efx;
1049 	unsigned int index, size, start;
1050 	u32 flow_id;
1051 
1052 	if (!mutex_trylock(&efx->rps_mutex))
1053 		return false;
1054 	expire_one = efx->type->filter_rfs_expire_one;
1055 	index = channel->rfs_expire_index;
1056 	start = index;
1057 	size = efx->type->max_rx_ip_filters;
1058 	while (quota) {
1059 		flow_id = channel->rps_flow_id[index];
1060 
1061 		if (flow_id != RPS_FLOW_ID_INVALID) {
1062 			quota--;
1063 			if (expire_one(efx, flow_id, index)) {
1064 				netif_info(efx, rx_status, efx->net_dev,
1065 					   "expired filter %d [channel %u flow %u]\n",
1066 					   index, channel->channel, flow_id);
1067 				channel->rps_flow_id[index] = RPS_FLOW_ID_INVALID;
1068 				channel->rfs_filter_count--;
1069 			}
1070 		}
1071 		if (++index == size)
1072 			index = 0;
1073 		/* If we were called with a quota that exceeds the total number
1074 		 * of filters in the table (which shouldn't happen, but could
1075 		 * if two callers race), ensure that we don't loop forever -
1076 		 * stop when we've examined every row of the table.
1077 		 */
1078 		if (index == start)
1079 			break;
1080 	}
1081 
1082 	channel->rfs_expire_index = index;
1083 	mutex_unlock(&efx->rps_mutex);
1084 	return true;
1085 }
1086 
1087 #endif /* CONFIG_RFS_ACCEL */
1088