xref: /openbmc/linux/drivers/net/ethernet/sfc/rx.c (revision f7777dcc)
1 /****************************************************************************
2  * Driver for Solarflare network controllers and boards
3  * Copyright 2005-2006 Fen Systems Ltd.
4  * Copyright 2005-2013 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 <linux/socket.h>
12 #include <linux/in.h>
13 #include <linux/slab.h>
14 #include <linux/ip.h>
15 #include <linux/tcp.h>
16 #include <linux/udp.h>
17 #include <linux/prefetch.h>
18 #include <linux/moduleparam.h>
19 #include <linux/iommu.h>
20 #include <net/ip.h>
21 #include <net/checksum.h>
22 #include "net_driver.h"
23 #include "efx.h"
24 #include "filter.h"
25 #include "nic.h"
26 #include "selftest.h"
27 #include "workarounds.h"
28 
29 /* Preferred number of descriptors to fill at once */
30 #define EFX_RX_PREFERRED_BATCH 8U
31 
32 /* Number of RX buffers to recycle pages for.  When creating the RX page recycle
33  * ring, this number is divided by the number of buffers per page to calculate
34  * the number of pages to store in the RX page recycle ring.
35  */
36 #define EFX_RECYCLE_RING_SIZE_IOMMU 4096
37 #define EFX_RECYCLE_RING_SIZE_NOIOMMU (2 * EFX_RX_PREFERRED_BATCH)
38 
39 /* Size of buffer allocated for skb header area. */
40 #define EFX_SKB_HEADERS  128u
41 
42 /* This is the percentage fill level below which new RX descriptors
43  * will be added to the RX descriptor ring.
44  */
45 static unsigned int rx_refill_threshold;
46 
47 /* Each packet can consume up to ceil(max_frame_len / buffer_size) buffers */
48 #define EFX_RX_MAX_FRAGS DIV_ROUND_UP(EFX_MAX_FRAME_LEN(EFX_MAX_MTU), \
49 				      EFX_RX_USR_BUF_SIZE)
50 
51 /*
52  * RX maximum head room required.
53  *
54  * This must be at least 1 to prevent overflow, plus one packet-worth
55  * to allow pipelined receives.
56  */
57 #define EFX_RXD_HEAD_ROOM (1 + EFX_RX_MAX_FRAGS)
58 
59 static inline u8 *efx_rx_buf_va(struct efx_rx_buffer *buf)
60 {
61 	return page_address(buf->page) + buf->page_offset;
62 }
63 
64 static inline u32 efx_rx_buf_hash(struct efx_nic *efx, const u8 *eh)
65 {
66 #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
67 	return __le32_to_cpup((const __le32 *)(eh + efx->rx_packet_hash_offset));
68 #else
69 	const u8 *data = eh + efx->rx_packet_hash_offset;
70 	return (u32)data[0]	  |
71 	       (u32)data[1] << 8  |
72 	       (u32)data[2] << 16 |
73 	       (u32)data[3] << 24;
74 #endif
75 }
76 
77 static inline struct efx_rx_buffer *
78 efx_rx_buf_next(struct efx_rx_queue *rx_queue, struct efx_rx_buffer *rx_buf)
79 {
80 	if (unlikely(rx_buf == efx_rx_buffer(rx_queue, rx_queue->ptr_mask)))
81 		return efx_rx_buffer(rx_queue, 0);
82 	else
83 		return rx_buf + 1;
84 }
85 
86 static inline void efx_sync_rx_buffer(struct efx_nic *efx,
87 				      struct efx_rx_buffer *rx_buf,
88 				      unsigned int len)
89 {
90 	dma_sync_single_for_cpu(&efx->pci_dev->dev, rx_buf->dma_addr, len,
91 				DMA_FROM_DEVICE);
92 }
93 
94 void efx_rx_config_page_split(struct efx_nic *efx)
95 {
96 	efx->rx_page_buf_step = ALIGN(efx->rx_dma_len + NET_IP_ALIGN,
97 				      EFX_RX_BUF_ALIGNMENT);
98 	efx->rx_bufs_per_page = efx->rx_buffer_order ? 1 :
99 		((PAGE_SIZE - sizeof(struct efx_rx_page_state)) /
100 		 efx->rx_page_buf_step);
101 	efx->rx_buffer_truesize = (PAGE_SIZE << efx->rx_buffer_order) /
102 		efx->rx_bufs_per_page;
103 	efx->rx_pages_per_batch = DIV_ROUND_UP(EFX_RX_PREFERRED_BATCH,
104 					       efx->rx_bufs_per_page);
105 }
106 
107 /* Check the RX page recycle ring for a page that can be reused. */
108 static struct page *efx_reuse_page(struct efx_rx_queue *rx_queue)
109 {
110 	struct efx_nic *efx = rx_queue->efx;
111 	struct page *page;
112 	struct efx_rx_page_state *state;
113 	unsigned index;
114 
115 	index = rx_queue->page_remove & rx_queue->page_ptr_mask;
116 	page = rx_queue->page_ring[index];
117 	if (page == NULL)
118 		return NULL;
119 
120 	rx_queue->page_ring[index] = NULL;
121 	/* page_remove cannot exceed page_add. */
122 	if (rx_queue->page_remove != rx_queue->page_add)
123 		++rx_queue->page_remove;
124 
125 	/* If page_count is 1 then we hold the only reference to this page. */
126 	if (page_count(page) == 1) {
127 		++rx_queue->page_recycle_count;
128 		return page;
129 	} else {
130 		state = page_address(page);
131 		dma_unmap_page(&efx->pci_dev->dev, state->dma_addr,
132 			       PAGE_SIZE << efx->rx_buffer_order,
133 			       DMA_FROM_DEVICE);
134 		put_page(page);
135 		++rx_queue->page_recycle_failed;
136 	}
137 
138 	return NULL;
139 }
140 
141 /**
142  * efx_init_rx_buffers - create EFX_RX_BATCH page-based RX buffers
143  *
144  * @rx_queue:		Efx RX queue
145  *
146  * This allocates a batch of pages, maps them for DMA, and populates
147  * struct efx_rx_buffers for each one. Return a negative error code or
148  * 0 on success. If a single page can be used for multiple buffers,
149  * then the page will either be inserted fully, or not at all.
150  */
151 static int efx_init_rx_buffers(struct efx_rx_queue *rx_queue)
152 {
153 	struct efx_nic *efx = rx_queue->efx;
154 	struct efx_rx_buffer *rx_buf;
155 	struct page *page;
156 	unsigned int page_offset;
157 	struct efx_rx_page_state *state;
158 	dma_addr_t dma_addr;
159 	unsigned index, count;
160 
161 	count = 0;
162 	do {
163 		page = efx_reuse_page(rx_queue);
164 		if (page == NULL) {
165 			page = alloc_pages(__GFP_COLD | __GFP_COMP | GFP_ATOMIC,
166 					   efx->rx_buffer_order);
167 			if (unlikely(page == NULL))
168 				return -ENOMEM;
169 			dma_addr =
170 				dma_map_page(&efx->pci_dev->dev, page, 0,
171 					     PAGE_SIZE << efx->rx_buffer_order,
172 					     DMA_FROM_DEVICE);
173 			if (unlikely(dma_mapping_error(&efx->pci_dev->dev,
174 						       dma_addr))) {
175 				__free_pages(page, efx->rx_buffer_order);
176 				return -EIO;
177 			}
178 			state = page_address(page);
179 			state->dma_addr = dma_addr;
180 		} else {
181 			state = page_address(page);
182 			dma_addr = state->dma_addr;
183 		}
184 
185 		dma_addr += sizeof(struct efx_rx_page_state);
186 		page_offset = sizeof(struct efx_rx_page_state);
187 
188 		do {
189 			index = rx_queue->added_count & rx_queue->ptr_mask;
190 			rx_buf = efx_rx_buffer(rx_queue, index);
191 			rx_buf->dma_addr = dma_addr + NET_IP_ALIGN;
192 			rx_buf->page = page;
193 			rx_buf->page_offset = page_offset + NET_IP_ALIGN;
194 			rx_buf->len = efx->rx_dma_len;
195 			rx_buf->flags = 0;
196 			++rx_queue->added_count;
197 			get_page(page);
198 			dma_addr += efx->rx_page_buf_step;
199 			page_offset += efx->rx_page_buf_step;
200 		} while (page_offset + efx->rx_page_buf_step <= PAGE_SIZE);
201 
202 		rx_buf->flags = EFX_RX_BUF_LAST_IN_PAGE;
203 	} while (++count < efx->rx_pages_per_batch);
204 
205 	return 0;
206 }
207 
208 /* Unmap a DMA-mapped page.  This function is only called for the final RX
209  * buffer in a page.
210  */
211 static void efx_unmap_rx_buffer(struct efx_nic *efx,
212 				struct efx_rx_buffer *rx_buf)
213 {
214 	struct page *page = rx_buf->page;
215 
216 	if (page) {
217 		struct efx_rx_page_state *state = page_address(page);
218 		dma_unmap_page(&efx->pci_dev->dev,
219 			       state->dma_addr,
220 			       PAGE_SIZE << efx->rx_buffer_order,
221 			       DMA_FROM_DEVICE);
222 	}
223 }
224 
225 static void efx_free_rx_buffer(struct efx_rx_buffer *rx_buf)
226 {
227 	if (rx_buf->page) {
228 		put_page(rx_buf->page);
229 		rx_buf->page = NULL;
230 	}
231 }
232 
233 /* Attempt to recycle the page if there is an RX recycle ring; the page can
234  * only be added if this is the final RX buffer, to prevent pages being used in
235  * the descriptor ring and appearing in the recycle ring simultaneously.
236  */
237 static void efx_recycle_rx_page(struct efx_channel *channel,
238 				struct efx_rx_buffer *rx_buf)
239 {
240 	struct page *page = rx_buf->page;
241 	struct efx_rx_queue *rx_queue = efx_channel_get_rx_queue(channel);
242 	struct efx_nic *efx = rx_queue->efx;
243 	unsigned index;
244 
245 	/* Only recycle the page after processing the final buffer. */
246 	if (!(rx_buf->flags & EFX_RX_BUF_LAST_IN_PAGE))
247 		return;
248 
249 	index = rx_queue->page_add & rx_queue->page_ptr_mask;
250 	if (rx_queue->page_ring[index] == NULL) {
251 		unsigned read_index = rx_queue->page_remove &
252 			rx_queue->page_ptr_mask;
253 
254 		/* The next slot in the recycle ring is available, but
255 		 * increment page_remove if the read pointer currently
256 		 * points here.
257 		 */
258 		if (read_index == index)
259 			++rx_queue->page_remove;
260 		rx_queue->page_ring[index] = page;
261 		++rx_queue->page_add;
262 		return;
263 	}
264 	++rx_queue->page_recycle_full;
265 	efx_unmap_rx_buffer(efx, rx_buf);
266 	put_page(rx_buf->page);
267 }
268 
269 static void efx_fini_rx_buffer(struct efx_rx_queue *rx_queue,
270 			       struct efx_rx_buffer *rx_buf)
271 {
272 	/* Release the page reference we hold for the buffer. */
273 	if (rx_buf->page)
274 		put_page(rx_buf->page);
275 
276 	/* If this is the last buffer in a page, unmap and free it. */
277 	if (rx_buf->flags & EFX_RX_BUF_LAST_IN_PAGE) {
278 		efx_unmap_rx_buffer(rx_queue->efx, rx_buf);
279 		efx_free_rx_buffer(rx_buf);
280 	}
281 	rx_buf->page = NULL;
282 }
283 
284 /* Recycle the pages that are used by buffers that have just been received. */
285 static void efx_recycle_rx_pages(struct efx_channel *channel,
286 				 struct efx_rx_buffer *rx_buf,
287 				 unsigned int n_frags)
288 {
289 	struct efx_rx_queue *rx_queue = efx_channel_get_rx_queue(channel);
290 
291 	do {
292 		efx_recycle_rx_page(channel, rx_buf);
293 		rx_buf = efx_rx_buf_next(rx_queue, rx_buf);
294 	} while (--n_frags);
295 }
296 
297 static void efx_discard_rx_packet(struct efx_channel *channel,
298 				  struct efx_rx_buffer *rx_buf,
299 				  unsigned int n_frags)
300 {
301 	struct efx_rx_queue *rx_queue = efx_channel_get_rx_queue(channel);
302 
303 	efx_recycle_rx_pages(channel, rx_buf, n_frags);
304 
305 	do {
306 		efx_free_rx_buffer(rx_buf);
307 		rx_buf = efx_rx_buf_next(rx_queue, rx_buf);
308 	} while (--n_frags);
309 }
310 
311 /**
312  * efx_fast_push_rx_descriptors - push new RX descriptors quickly
313  * @rx_queue:		RX descriptor queue
314  *
315  * This will aim to fill the RX descriptor queue up to
316  * @rx_queue->@max_fill. If there is insufficient atomic
317  * memory to do so, a slow fill will be scheduled.
318  *
319  * The caller must provide serialisation (none is used here). In practise,
320  * this means this function must run from the NAPI handler, or be called
321  * when NAPI is disabled.
322  */
323 void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue)
324 {
325 	struct efx_nic *efx = rx_queue->efx;
326 	unsigned int fill_level, batch_size;
327 	int space, rc = 0;
328 
329 	if (!rx_queue->refill_enabled)
330 		return;
331 
332 	/* Calculate current fill level, and exit if we don't need to fill */
333 	fill_level = (rx_queue->added_count - rx_queue->removed_count);
334 	EFX_BUG_ON_PARANOID(fill_level > rx_queue->efx->rxq_entries);
335 	if (fill_level >= rx_queue->fast_fill_trigger)
336 		goto out;
337 
338 	/* Record minimum fill level */
339 	if (unlikely(fill_level < rx_queue->min_fill)) {
340 		if (fill_level)
341 			rx_queue->min_fill = fill_level;
342 	}
343 
344 	batch_size = efx->rx_pages_per_batch * efx->rx_bufs_per_page;
345 	space = rx_queue->max_fill - fill_level;
346 	EFX_BUG_ON_PARANOID(space < batch_size);
347 
348 	netif_vdbg(rx_queue->efx, rx_status, rx_queue->efx->net_dev,
349 		   "RX queue %d fast-filling descriptor ring from"
350 		   " level %d to level %d\n",
351 		   efx_rx_queue_index(rx_queue), fill_level,
352 		   rx_queue->max_fill);
353 
354 
355 	do {
356 		rc = efx_init_rx_buffers(rx_queue);
357 		if (unlikely(rc)) {
358 			/* Ensure that we don't leave the rx queue empty */
359 			if (rx_queue->added_count == rx_queue->removed_count)
360 				efx_schedule_slow_fill(rx_queue);
361 			goto out;
362 		}
363 	} while ((space -= batch_size) >= batch_size);
364 
365 	netif_vdbg(rx_queue->efx, rx_status, rx_queue->efx->net_dev,
366 		   "RX queue %d fast-filled descriptor ring "
367 		   "to level %d\n", efx_rx_queue_index(rx_queue),
368 		   rx_queue->added_count - rx_queue->removed_count);
369 
370  out:
371 	if (rx_queue->notified_count != rx_queue->added_count)
372 		efx_nic_notify_rx_desc(rx_queue);
373 }
374 
375 void efx_rx_slow_fill(unsigned long context)
376 {
377 	struct efx_rx_queue *rx_queue = (struct efx_rx_queue *)context;
378 
379 	/* Post an event to cause NAPI to run and refill the queue */
380 	efx_nic_generate_fill_event(rx_queue);
381 	++rx_queue->slow_fill_count;
382 }
383 
384 static void efx_rx_packet__check_len(struct efx_rx_queue *rx_queue,
385 				     struct efx_rx_buffer *rx_buf,
386 				     int len)
387 {
388 	struct efx_nic *efx = rx_queue->efx;
389 	unsigned max_len = rx_buf->len - efx->type->rx_buffer_padding;
390 
391 	if (likely(len <= max_len))
392 		return;
393 
394 	/* The packet must be discarded, but this is only a fatal error
395 	 * if the caller indicated it was
396 	 */
397 	rx_buf->flags |= EFX_RX_PKT_DISCARD;
398 
399 	if ((len > rx_buf->len) && EFX_WORKAROUND_8071(efx)) {
400 		if (net_ratelimit())
401 			netif_err(efx, rx_err, efx->net_dev,
402 				  " RX queue %d seriously overlength "
403 				  "RX event (0x%x > 0x%x+0x%x). Leaking\n",
404 				  efx_rx_queue_index(rx_queue), len, max_len,
405 				  efx->type->rx_buffer_padding);
406 		efx_schedule_reset(efx, RESET_TYPE_RX_RECOVERY);
407 	} else {
408 		if (net_ratelimit())
409 			netif_err(efx, rx_err, efx->net_dev,
410 				  " RX queue %d overlength RX event "
411 				  "(0x%x > 0x%x)\n",
412 				  efx_rx_queue_index(rx_queue), len, max_len);
413 	}
414 
415 	efx_rx_queue_channel(rx_queue)->n_rx_overlength++;
416 }
417 
418 /* Pass a received packet up through GRO.  GRO can handle pages
419  * regardless of checksum state and skbs with a good checksum.
420  */
421 static void
422 efx_rx_packet_gro(struct efx_channel *channel, struct efx_rx_buffer *rx_buf,
423 		  unsigned int n_frags, u8 *eh)
424 {
425 	struct napi_struct *napi = &channel->napi_str;
426 	gro_result_t gro_result;
427 	struct efx_nic *efx = channel->efx;
428 	struct sk_buff *skb;
429 
430 	skb = napi_get_frags(napi);
431 	if (unlikely(!skb)) {
432 		while (n_frags--) {
433 			put_page(rx_buf->page);
434 			rx_buf->page = NULL;
435 			rx_buf = efx_rx_buf_next(&channel->rx_queue, rx_buf);
436 		}
437 		return;
438 	}
439 
440 	if (efx->net_dev->features & NETIF_F_RXHASH)
441 		skb->rxhash = efx_rx_buf_hash(efx, eh);
442 	skb->ip_summed = ((rx_buf->flags & EFX_RX_PKT_CSUMMED) ?
443 			  CHECKSUM_UNNECESSARY : CHECKSUM_NONE);
444 
445 	for (;;) {
446 		skb_fill_page_desc(skb, skb_shinfo(skb)->nr_frags,
447 				   rx_buf->page, rx_buf->page_offset,
448 				   rx_buf->len);
449 		rx_buf->page = NULL;
450 		skb->len += rx_buf->len;
451 		if (skb_shinfo(skb)->nr_frags == n_frags)
452 			break;
453 
454 		rx_buf = efx_rx_buf_next(&channel->rx_queue, rx_buf);
455 	}
456 
457 	skb->data_len = skb->len;
458 	skb->truesize += n_frags * efx->rx_buffer_truesize;
459 
460 	skb_record_rx_queue(skb, channel->rx_queue.core_index);
461 
462 	gro_result = napi_gro_frags(napi);
463 	if (gro_result != GRO_DROP)
464 		channel->irq_mod_score += 2;
465 }
466 
467 /* Allocate and construct an SKB around page fragments */
468 static struct sk_buff *efx_rx_mk_skb(struct efx_channel *channel,
469 				     struct efx_rx_buffer *rx_buf,
470 				     unsigned int n_frags,
471 				     u8 *eh, int hdr_len)
472 {
473 	struct efx_nic *efx = channel->efx;
474 	struct sk_buff *skb;
475 
476 	/* Allocate an SKB to store the headers */
477 	skb = netdev_alloc_skb(efx->net_dev, hdr_len + EFX_PAGE_SKB_ALIGN);
478 	if (unlikely(skb == NULL))
479 		return NULL;
480 
481 	EFX_BUG_ON_PARANOID(rx_buf->len < hdr_len);
482 
483 	skb_reserve(skb, EFX_PAGE_SKB_ALIGN);
484 	memcpy(__skb_put(skb, hdr_len), eh, hdr_len);
485 
486 	/* Append the remaining page(s) onto the frag list */
487 	if (rx_buf->len > hdr_len) {
488 		rx_buf->page_offset += hdr_len;
489 		rx_buf->len -= hdr_len;
490 
491 		for (;;) {
492 			skb_fill_page_desc(skb, skb_shinfo(skb)->nr_frags,
493 					   rx_buf->page, rx_buf->page_offset,
494 					   rx_buf->len);
495 			rx_buf->page = NULL;
496 			skb->len += rx_buf->len;
497 			skb->data_len += rx_buf->len;
498 			if (skb_shinfo(skb)->nr_frags == n_frags)
499 				break;
500 
501 			rx_buf = efx_rx_buf_next(&channel->rx_queue, rx_buf);
502 		}
503 	} else {
504 		__free_pages(rx_buf->page, efx->rx_buffer_order);
505 		rx_buf->page = NULL;
506 		n_frags = 0;
507 	}
508 
509 	skb->truesize += n_frags * efx->rx_buffer_truesize;
510 
511 	/* Move past the ethernet header */
512 	skb->protocol = eth_type_trans(skb, efx->net_dev);
513 
514 	return skb;
515 }
516 
517 void efx_rx_packet(struct efx_rx_queue *rx_queue, unsigned int index,
518 		   unsigned int n_frags, unsigned int len, u16 flags)
519 {
520 	struct efx_nic *efx = rx_queue->efx;
521 	struct efx_channel *channel = efx_rx_queue_channel(rx_queue);
522 	struct efx_rx_buffer *rx_buf;
523 
524 	rx_buf = efx_rx_buffer(rx_queue, index);
525 	rx_buf->flags |= flags;
526 
527 	/* Validate the number of fragments and completed length */
528 	if (n_frags == 1) {
529 		if (!(flags & EFX_RX_PKT_PREFIX_LEN))
530 			efx_rx_packet__check_len(rx_queue, rx_buf, len);
531 	} else if (unlikely(n_frags > EFX_RX_MAX_FRAGS) ||
532 		   unlikely(len <= (n_frags - 1) * efx->rx_dma_len) ||
533 		   unlikely(len > n_frags * efx->rx_dma_len) ||
534 		   unlikely(!efx->rx_scatter)) {
535 		/* If this isn't an explicit discard request, either
536 		 * the hardware or the driver is broken.
537 		 */
538 		WARN_ON(!(len == 0 && rx_buf->flags & EFX_RX_PKT_DISCARD));
539 		rx_buf->flags |= EFX_RX_PKT_DISCARD;
540 	}
541 
542 	netif_vdbg(efx, rx_status, efx->net_dev,
543 		   "RX queue %d received ids %x-%x len %d %s%s\n",
544 		   efx_rx_queue_index(rx_queue), index,
545 		   (index + n_frags - 1) & rx_queue->ptr_mask, len,
546 		   (rx_buf->flags & EFX_RX_PKT_CSUMMED) ? " [SUMMED]" : "",
547 		   (rx_buf->flags & EFX_RX_PKT_DISCARD) ? " [DISCARD]" : "");
548 
549 	/* Discard packet, if instructed to do so.  Process the
550 	 * previous receive first.
551 	 */
552 	if (unlikely(rx_buf->flags & EFX_RX_PKT_DISCARD)) {
553 		efx_rx_flush_packet(channel);
554 		efx_discard_rx_packet(channel, rx_buf, n_frags);
555 		return;
556 	}
557 
558 	if (n_frags == 1 && !(flags & EFX_RX_PKT_PREFIX_LEN))
559 		rx_buf->len = len;
560 
561 	/* Release and/or sync the DMA mapping - assumes all RX buffers
562 	 * consumed in-order per RX queue.
563 	 */
564 	efx_sync_rx_buffer(efx, rx_buf, rx_buf->len);
565 
566 	/* Prefetch nice and early so data will (hopefully) be in cache by
567 	 * the time we look at it.
568 	 */
569 	prefetch(efx_rx_buf_va(rx_buf));
570 
571 	rx_buf->page_offset += efx->rx_prefix_size;
572 	rx_buf->len -= efx->rx_prefix_size;
573 
574 	if (n_frags > 1) {
575 		/* Release/sync DMA mapping for additional fragments.
576 		 * Fix length for last fragment.
577 		 */
578 		unsigned int tail_frags = n_frags - 1;
579 
580 		for (;;) {
581 			rx_buf = efx_rx_buf_next(rx_queue, rx_buf);
582 			if (--tail_frags == 0)
583 				break;
584 			efx_sync_rx_buffer(efx, rx_buf, efx->rx_dma_len);
585 		}
586 		rx_buf->len = len - (n_frags - 1) * efx->rx_dma_len;
587 		efx_sync_rx_buffer(efx, rx_buf, rx_buf->len);
588 	}
589 
590 	/* All fragments have been DMA-synced, so recycle pages. */
591 	rx_buf = efx_rx_buffer(rx_queue, index);
592 	efx_recycle_rx_pages(channel, rx_buf, n_frags);
593 
594 	/* Pipeline receives so that we give time for packet headers to be
595 	 * prefetched into cache.
596 	 */
597 	efx_rx_flush_packet(channel);
598 	channel->rx_pkt_n_frags = n_frags;
599 	channel->rx_pkt_index = index;
600 }
601 
602 static void efx_rx_deliver(struct efx_channel *channel, u8 *eh,
603 			   struct efx_rx_buffer *rx_buf,
604 			   unsigned int n_frags)
605 {
606 	struct sk_buff *skb;
607 	u16 hdr_len = min_t(u16, rx_buf->len, EFX_SKB_HEADERS);
608 
609 	skb = efx_rx_mk_skb(channel, rx_buf, n_frags, eh, hdr_len);
610 	if (unlikely(skb == NULL)) {
611 		efx_free_rx_buffer(rx_buf);
612 		return;
613 	}
614 	skb_record_rx_queue(skb, channel->rx_queue.core_index);
615 
616 	/* Set the SKB flags */
617 	skb_checksum_none_assert(skb);
618 	if (likely(rx_buf->flags & EFX_RX_PKT_CSUMMED))
619 		skb->ip_summed = CHECKSUM_UNNECESSARY;
620 
621 	if (channel->type->receive_skb)
622 		if (channel->type->receive_skb(channel, skb))
623 			return;
624 
625 	/* Pass the packet up */
626 	netif_receive_skb(skb);
627 }
628 
629 /* Handle a received packet.  Second half: Touches packet payload. */
630 void __efx_rx_packet(struct efx_channel *channel)
631 {
632 	struct efx_nic *efx = channel->efx;
633 	struct efx_rx_buffer *rx_buf =
634 		efx_rx_buffer(&channel->rx_queue, channel->rx_pkt_index);
635 	u8 *eh = efx_rx_buf_va(rx_buf);
636 
637 	/* Read length from the prefix if necessary.  This already
638 	 * excludes the length of the prefix itself.
639 	 */
640 	if (rx_buf->flags & EFX_RX_PKT_PREFIX_LEN)
641 		rx_buf->len = le16_to_cpup((__le16 *)
642 					   (eh + efx->rx_packet_len_offset));
643 
644 	/* If we're in loopback test, then pass the packet directly to the
645 	 * loopback layer, and free the rx_buf here
646 	 */
647 	if (unlikely(efx->loopback_selftest)) {
648 		efx_loopback_rx_packet(efx, eh, rx_buf->len);
649 		efx_free_rx_buffer(rx_buf);
650 		goto out;
651 	}
652 
653 	if (unlikely(!(efx->net_dev->features & NETIF_F_RXCSUM)))
654 		rx_buf->flags &= ~EFX_RX_PKT_CSUMMED;
655 
656 	if ((rx_buf->flags & EFX_RX_PKT_TCP) && !channel->type->receive_skb)
657 		efx_rx_packet_gro(channel, rx_buf, channel->rx_pkt_n_frags, eh);
658 	else
659 		efx_rx_deliver(channel, eh, rx_buf, channel->rx_pkt_n_frags);
660 out:
661 	channel->rx_pkt_n_frags = 0;
662 }
663 
664 int efx_probe_rx_queue(struct efx_rx_queue *rx_queue)
665 {
666 	struct efx_nic *efx = rx_queue->efx;
667 	unsigned int entries;
668 	int rc;
669 
670 	/* Create the smallest power-of-two aligned ring */
671 	entries = max(roundup_pow_of_two(efx->rxq_entries), EFX_MIN_DMAQ_SIZE);
672 	EFX_BUG_ON_PARANOID(entries > EFX_MAX_DMAQ_SIZE);
673 	rx_queue->ptr_mask = entries - 1;
674 
675 	netif_dbg(efx, probe, efx->net_dev,
676 		  "creating RX queue %d size %#x mask %#x\n",
677 		  efx_rx_queue_index(rx_queue), efx->rxq_entries,
678 		  rx_queue->ptr_mask);
679 
680 	/* Allocate RX buffers */
681 	rx_queue->buffer = kcalloc(entries, sizeof(*rx_queue->buffer),
682 				   GFP_KERNEL);
683 	if (!rx_queue->buffer)
684 		return -ENOMEM;
685 
686 	rc = efx_nic_probe_rx(rx_queue);
687 	if (rc) {
688 		kfree(rx_queue->buffer);
689 		rx_queue->buffer = NULL;
690 	}
691 
692 	return rc;
693 }
694 
695 static void efx_init_rx_recycle_ring(struct efx_nic *efx,
696 				     struct efx_rx_queue *rx_queue)
697 {
698 	unsigned int bufs_in_recycle_ring, page_ring_size;
699 
700 	/* Set the RX recycle ring size */
701 #ifdef CONFIG_PPC64
702 	bufs_in_recycle_ring = EFX_RECYCLE_RING_SIZE_IOMMU;
703 #else
704 	if (iommu_present(&pci_bus_type))
705 		bufs_in_recycle_ring = EFX_RECYCLE_RING_SIZE_IOMMU;
706 	else
707 		bufs_in_recycle_ring = EFX_RECYCLE_RING_SIZE_NOIOMMU;
708 #endif /* CONFIG_PPC64 */
709 
710 	page_ring_size = roundup_pow_of_two(bufs_in_recycle_ring /
711 					    efx->rx_bufs_per_page);
712 	rx_queue->page_ring = kcalloc(page_ring_size,
713 				      sizeof(*rx_queue->page_ring), GFP_KERNEL);
714 	rx_queue->page_ptr_mask = page_ring_size - 1;
715 }
716 
717 void efx_init_rx_queue(struct efx_rx_queue *rx_queue)
718 {
719 	struct efx_nic *efx = rx_queue->efx;
720 	unsigned int max_fill, trigger, max_trigger;
721 
722 	netif_dbg(rx_queue->efx, drv, rx_queue->efx->net_dev,
723 		  "initialising RX queue %d\n", efx_rx_queue_index(rx_queue));
724 
725 	/* Initialise ptr fields */
726 	rx_queue->added_count = 0;
727 	rx_queue->notified_count = 0;
728 	rx_queue->removed_count = 0;
729 	rx_queue->min_fill = -1U;
730 	efx_init_rx_recycle_ring(efx, rx_queue);
731 
732 	rx_queue->page_remove = 0;
733 	rx_queue->page_add = rx_queue->page_ptr_mask + 1;
734 	rx_queue->page_recycle_count = 0;
735 	rx_queue->page_recycle_failed = 0;
736 	rx_queue->page_recycle_full = 0;
737 
738 	/* Initialise limit fields */
739 	max_fill = efx->rxq_entries - EFX_RXD_HEAD_ROOM;
740 	max_trigger =
741 		max_fill - efx->rx_pages_per_batch * efx->rx_bufs_per_page;
742 	if (rx_refill_threshold != 0) {
743 		trigger = max_fill * min(rx_refill_threshold, 100U) / 100U;
744 		if (trigger > max_trigger)
745 			trigger = max_trigger;
746 	} else {
747 		trigger = max_trigger;
748 	}
749 
750 	rx_queue->max_fill = max_fill;
751 	rx_queue->fast_fill_trigger = trigger;
752 	rx_queue->refill_enabled = true;
753 
754 	/* Set up RX descriptor ring */
755 	efx_nic_init_rx(rx_queue);
756 }
757 
758 void efx_fini_rx_queue(struct efx_rx_queue *rx_queue)
759 {
760 	int i;
761 	struct efx_nic *efx = rx_queue->efx;
762 	struct efx_rx_buffer *rx_buf;
763 
764 	netif_dbg(rx_queue->efx, drv, rx_queue->efx->net_dev,
765 		  "shutting down RX queue %d\n", efx_rx_queue_index(rx_queue));
766 
767 	del_timer_sync(&rx_queue->slow_fill);
768 
769 	/* Release RX buffers from the current read ptr to the write ptr */
770 	if (rx_queue->buffer) {
771 		for (i = rx_queue->removed_count; i < rx_queue->added_count;
772 		     i++) {
773 			unsigned index = i & rx_queue->ptr_mask;
774 			rx_buf = efx_rx_buffer(rx_queue, index);
775 			efx_fini_rx_buffer(rx_queue, rx_buf);
776 		}
777 	}
778 
779 	/* Unmap and release the pages in the recycle ring. Remove the ring. */
780 	for (i = 0; i <= rx_queue->page_ptr_mask; i++) {
781 		struct page *page = rx_queue->page_ring[i];
782 		struct efx_rx_page_state *state;
783 
784 		if (page == NULL)
785 			continue;
786 
787 		state = page_address(page);
788 		dma_unmap_page(&efx->pci_dev->dev, state->dma_addr,
789 			       PAGE_SIZE << efx->rx_buffer_order,
790 			       DMA_FROM_DEVICE);
791 		put_page(page);
792 	}
793 	kfree(rx_queue->page_ring);
794 	rx_queue->page_ring = NULL;
795 }
796 
797 void efx_remove_rx_queue(struct efx_rx_queue *rx_queue)
798 {
799 	netif_dbg(rx_queue->efx, drv, rx_queue->efx->net_dev,
800 		  "destroying RX queue %d\n", efx_rx_queue_index(rx_queue));
801 
802 	efx_nic_remove_rx(rx_queue);
803 
804 	kfree(rx_queue->buffer);
805 	rx_queue->buffer = NULL;
806 }
807 
808 
809 module_param(rx_refill_threshold, uint, 0444);
810 MODULE_PARM_DESC(rx_refill_threshold,
811 		 "RX descriptor ring refill threshold (%)");
812 
813 #ifdef CONFIG_RFS_ACCEL
814 
815 int efx_filter_rfs(struct net_device *net_dev, const struct sk_buff *skb,
816 		   u16 rxq_index, u32 flow_id)
817 {
818 	struct efx_nic *efx = netdev_priv(net_dev);
819 	struct efx_channel *channel;
820 	struct efx_filter_spec spec;
821 	const struct iphdr *ip;
822 	const __be16 *ports;
823 	int nhoff;
824 	int rc;
825 
826 	nhoff = skb_network_offset(skb);
827 
828 	if (skb->protocol == htons(ETH_P_8021Q)) {
829 		EFX_BUG_ON_PARANOID(skb_headlen(skb) <
830 				    nhoff + sizeof(struct vlan_hdr));
831 		if (((const struct vlan_hdr *)skb->data + nhoff)->
832 		    h_vlan_encapsulated_proto != htons(ETH_P_IP))
833 			return -EPROTONOSUPPORT;
834 
835 		/* This is IP over 802.1q VLAN.  We can't filter on the
836 		 * IP 5-tuple and the vlan together, so just strip the
837 		 * vlan header and filter on the IP part.
838 		 */
839 		nhoff += sizeof(struct vlan_hdr);
840 	} else if (skb->protocol != htons(ETH_P_IP)) {
841 		return -EPROTONOSUPPORT;
842 	}
843 
844 	/* RFS must validate the IP header length before calling us */
845 	EFX_BUG_ON_PARANOID(skb_headlen(skb) < nhoff + sizeof(*ip));
846 	ip = (const struct iphdr *)(skb->data + nhoff);
847 	if (ip_is_fragment(ip))
848 		return -EPROTONOSUPPORT;
849 	EFX_BUG_ON_PARANOID(skb_headlen(skb) < nhoff + 4 * ip->ihl + 4);
850 	ports = (const __be16 *)(skb->data + nhoff + 4 * ip->ihl);
851 
852 	efx_filter_init_rx(&spec, EFX_FILTER_PRI_HINT,
853 			   efx->rx_scatter ? EFX_FILTER_FLAG_RX_SCATTER : 0,
854 			   rxq_index);
855 	rc = efx_filter_set_ipv4_full(&spec, ip->protocol,
856 				      ip->daddr, ports[1], ip->saddr, ports[0]);
857 	if (rc)
858 		return rc;
859 
860 	rc = efx->type->filter_rfs_insert(efx, &spec);
861 	if (rc < 0)
862 		return rc;
863 
864 	/* Remember this so we can check whether to expire the filter later */
865 	efx->rps_flow_id[rc] = flow_id;
866 	channel = efx_get_channel(efx, skb_get_rx_queue(skb));
867 	++channel->rfs_filters_added;
868 
869 	netif_info(efx, rx_status, efx->net_dev,
870 		   "steering %s %pI4:%u:%pI4:%u to queue %u [flow %u filter %d]\n",
871 		   (ip->protocol == IPPROTO_TCP) ? "TCP" : "UDP",
872 		   &ip->saddr, ntohs(ports[0]), &ip->daddr, ntohs(ports[1]),
873 		   rxq_index, flow_id, rc);
874 
875 	return rc;
876 }
877 
878 bool __efx_filter_rfs_expire(struct efx_nic *efx, unsigned int quota)
879 {
880 	bool (*expire_one)(struct efx_nic *efx, u32 flow_id, unsigned int index);
881 	unsigned int index, size;
882 	u32 flow_id;
883 
884 	if (!spin_trylock_bh(&efx->filter_lock))
885 		return false;
886 
887 	expire_one = efx->type->filter_rfs_expire_one;
888 	index = efx->rps_expire_index;
889 	size = efx->type->max_rx_ip_filters;
890 	while (quota--) {
891 		flow_id = efx->rps_flow_id[index];
892 		if (expire_one(efx, flow_id, index))
893 			netif_info(efx, rx_status, efx->net_dev,
894 				   "expired filter %d [flow %u]\n",
895 				   index, flow_id);
896 		if (++index == size)
897 			index = 0;
898 	}
899 	efx->rps_expire_index = index;
900 
901 	spin_unlock_bh(&efx->filter_lock);
902 	return true;
903 }
904 
905 #endif /* CONFIG_RFS_ACCEL */
906 
907 /**
908  * efx_filter_is_mc_recipient - test whether spec is a multicast recipient
909  * @spec: Specification to test
910  *
911  * Return: %true if the specification is a non-drop RX filter that
912  * matches a local MAC address I/G bit value of 1 or matches a local
913  * IPv4 or IPv6 address value in the respective multicast address
914  * range.  Otherwise %false.
915  */
916 bool efx_filter_is_mc_recipient(const struct efx_filter_spec *spec)
917 {
918 	if (!(spec->flags & EFX_FILTER_FLAG_RX) ||
919 	    spec->dmaq_id == EFX_FILTER_RX_DMAQ_ID_DROP)
920 		return false;
921 
922 	if (spec->match_flags &
923 	    (EFX_FILTER_MATCH_LOC_MAC | EFX_FILTER_MATCH_LOC_MAC_IG) &&
924 	    is_multicast_ether_addr(spec->loc_mac))
925 		return true;
926 
927 	if ((spec->match_flags &
928 	     (EFX_FILTER_MATCH_ETHER_TYPE | EFX_FILTER_MATCH_LOC_HOST)) ==
929 	    (EFX_FILTER_MATCH_ETHER_TYPE | EFX_FILTER_MATCH_LOC_HOST)) {
930 		if (spec->ether_type == htons(ETH_P_IP) &&
931 		    ipv4_is_multicast(spec->loc_host[0]))
932 			return true;
933 		if (spec->ether_type == htons(ETH_P_IPV6) &&
934 		    ((const u8 *)spec->loc_host)[0] == 0xff)
935 			return true;
936 	}
937 
938 	return false;
939 }
940