xref: /linux/drivers/net/ethernet/sfc/efx_channels.c (revision 6015fb905d89063231ed33bc15be19ef0fc339b8)
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/filter.h>
14 #include "efx_channels.h"
15 #include "efx.h"
16 #include "efx_common.h"
17 #include "tx_common.h"
18 #include "rx_common.h"
19 #include "nic.h"
20 #include "sriov.h"
21 #include "workarounds.h"
22 
23 /* This is the first interrupt mode to try out of:
24  * 0 => MSI-X
25  * 1 => MSI
26  * 2 => legacy
27  */
28 unsigned int efx_interrupt_mode = EFX_INT_MODE_MSIX;
29 
30 /* This is the requested number of CPUs to use for Receive-Side Scaling (RSS),
31  * i.e. the number of CPUs among which we may distribute simultaneous
32  * interrupt handling.
33  *
34  * Cards without MSI-X will only target one CPU via legacy or MSI interrupt.
35  * The default (0) means to assign an interrupt to each core.
36  */
37 unsigned int rss_cpus;
38 
39 static unsigned int irq_adapt_low_thresh = 8000;
40 module_param(irq_adapt_low_thresh, uint, 0644);
41 MODULE_PARM_DESC(irq_adapt_low_thresh,
42 		 "Threshold score for reducing IRQ moderation");
43 
44 static unsigned int irq_adapt_high_thresh = 16000;
45 module_param(irq_adapt_high_thresh, uint, 0644);
46 MODULE_PARM_DESC(irq_adapt_high_thresh,
47 		 "Threshold score for increasing IRQ moderation");
48 
49 /* This is the weight assigned to each of the (per-channel) virtual
50  * NAPI devices.
51  */
52 static int napi_weight = 64;
53 
54 /***************
55  * Housekeeping
56  ***************/
57 
58 int efx_channel_dummy_op_int(struct efx_channel *channel)
59 {
60 	return 0;
61 }
62 
63 void efx_channel_dummy_op_void(struct efx_channel *channel)
64 {
65 }
66 
67 static const struct efx_channel_type efx_default_channel_type = {
68 	.pre_probe		= efx_channel_dummy_op_int,
69 	.post_remove		= efx_channel_dummy_op_void,
70 	.get_name		= efx_get_channel_name,
71 	.copy			= efx_copy_channel,
72 	.want_txqs		= efx_default_channel_want_txqs,
73 	.keep_eventq		= false,
74 	.want_pio		= true,
75 };
76 
77 /*************
78  * INTERRUPTS
79  *************/
80 
81 static unsigned int count_online_cores(struct efx_nic *efx, bool local_node)
82 {
83 	cpumask_var_t filter_mask;
84 	unsigned int count;
85 	int cpu;
86 
87 	if (unlikely(!zalloc_cpumask_var(&filter_mask, GFP_KERNEL))) {
88 		netif_warn(efx, probe, efx->net_dev,
89 			   "RSS disabled due to allocation failure\n");
90 		return 1;
91 	}
92 
93 	cpumask_copy(filter_mask, cpu_online_mask);
94 	if (local_node) {
95 		int numa_node = pcibus_to_node(efx->pci_dev->bus);
96 
97 		cpumask_and(filter_mask, filter_mask, cpumask_of_node(numa_node));
98 	}
99 
100 	count = 0;
101 	for_each_cpu(cpu, filter_mask) {
102 		++count;
103 		cpumask_andnot(filter_mask, filter_mask, topology_sibling_cpumask(cpu));
104 	}
105 
106 	free_cpumask_var(filter_mask);
107 
108 	return count;
109 }
110 
111 static unsigned int efx_wanted_parallelism(struct efx_nic *efx)
112 {
113 	unsigned int count;
114 
115 	if (rss_cpus) {
116 		count = rss_cpus;
117 	} else {
118 		count = count_online_cores(efx, true);
119 
120 		/* If no online CPUs in local node, fallback to any online CPUs */
121 		if (count == 0)
122 			count = count_online_cores(efx, false);
123 	}
124 
125 	if (count > EFX_MAX_RX_QUEUES) {
126 		netif_cond_dbg(efx, probe, efx->net_dev, !rss_cpus, warn,
127 			       "Reducing number of rx queues from %u to %u.\n",
128 			       count, EFX_MAX_RX_QUEUES);
129 		count = EFX_MAX_RX_QUEUES;
130 	}
131 
132 	/* If RSS is requested for the PF *and* VFs then we can't write RSS
133 	 * table entries that are inaccessible to VFs
134 	 */
135 #ifdef CONFIG_SFC_SRIOV
136 	if (efx->type->sriov_wanted) {
137 		if (efx->type->sriov_wanted(efx) && efx_vf_size(efx) > 1 &&
138 		    count > efx_vf_size(efx)) {
139 			netif_warn(efx, probe, efx->net_dev,
140 				   "Reducing number of RSS channels from %u to %u for "
141 				   "VF support. Increase vf-msix-limit to use more "
142 				   "channels on the PF.\n",
143 				   count, efx_vf_size(efx));
144 			count = efx_vf_size(efx);
145 		}
146 	}
147 #endif
148 
149 	return count;
150 }
151 
152 static int efx_allocate_msix_channels(struct efx_nic *efx,
153 				      unsigned int max_channels,
154 				      unsigned int extra_channels,
155 				      unsigned int parallelism)
156 {
157 	unsigned int n_channels = parallelism;
158 	int vec_count;
159 	int tx_per_ev;
160 	int n_xdp_tx;
161 	int n_xdp_ev;
162 
163 	if (efx_separate_tx_channels)
164 		n_channels *= 2;
165 	n_channels += extra_channels;
166 
167 	/* To allow XDP transmit to happen from arbitrary NAPI contexts
168 	 * we allocate a TX queue per CPU. We share event queues across
169 	 * multiple tx queues, assuming tx and ev queues are both
170 	 * maximum size.
171 	 */
172 	tx_per_ev = EFX_MAX_EVQ_SIZE / EFX_TXQ_MAX_ENT(efx);
173 	tx_per_ev = min(tx_per_ev, EFX_MAX_TXQ_PER_CHANNEL);
174 	n_xdp_tx = num_possible_cpus();
175 	n_xdp_ev = DIV_ROUND_UP(n_xdp_tx, tx_per_ev);
176 
177 	vec_count = pci_msix_vec_count(efx->pci_dev);
178 	if (vec_count < 0)
179 		return vec_count;
180 
181 	max_channels = min_t(unsigned int, vec_count, max_channels);
182 
183 	/* Check resources.
184 	 * We need a channel per event queue, plus a VI per tx queue.
185 	 * This may be more pessimistic than it needs to be.
186 	 */
187 	if (n_channels >= max_channels) {
188 		efx->xdp_txq_queues_mode = EFX_XDP_TX_QUEUES_BORROWED;
189 		netif_warn(efx, drv, efx->net_dev,
190 			   "Insufficient resources for %d XDP event queues (%d other channels, max %d)\n",
191 			   n_xdp_ev, n_channels, max_channels);
192 		netif_warn(efx, drv, efx->net_dev,
193 			   "XDP_TX and XDP_REDIRECT might decrease device's performance\n");
194 	} else if (n_channels + n_xdp_tx > efx->max_vis) {
195 		efx->xdp_txq_queues_mode = EFX_XDP_TX_QUEUES_BORROWED;
196 		netif_warn(efx, drv, efx->net_dev,
197 			   "Insufficient resources for %d XDP TX queues (%d other channels, max VIs %d)\n",
198 			   n_xdp_tx, n_channels, efx->max_vis);
199 		netif_warn(efx, drv, efx->net_dev,
200 			   "XDP_TX and XDP_REDIRECT might decrease device's performance\n");
201 	} else if (n_channels + n_xdp_ev > max_channels) {
202 		efx->xdp_txq_queues_mode = EFX_XDP_TX_QUEUES_SHARED;
203 		netif_warn(efx, drv, efx->net_dev,
204 			   "Insufficient resources for %d XDP event queues (%d other channels, max %d)\n",
205 			   n_xdp_ev, n_channels, max_channels);
206 
207 		n_xdp_ev = max_channels - n_channels;
208 		netif_warn(efx, drv, efx->net_dev,
209 			   "XDP_TX and XDP_REDIRECT will work with reduced performance (%d cpus/tx_queue)\n",
210 			   DIV_ROUND_UP(n_xdp_tx, tx_per_ev * n_xdp_ev));
211 	} else {
212 		efx->xdp_txq_queues_mode = EFX_XDP_TX_QUEUES_DEDICATED;
213 	}
214 
215 	if (efx->xdp_txq_queues_mode != EFX_XDP_TX_QUEUES_BORROWED) {
216 		efx->n_xdp_channels = n_xdp_ev;
217 		efx->xdp_tx_per_channel = tx_per_ev;
218 		efx->xdp_tx_queue_count = n_xdp_tx;
219 		n_channels += n_xdp_ev;
220 		netif_dbg(efx, drv, efx->net_dev,
221 			  "Allocating %d TX and %d event queues for XDP\n",
222 			  n_xdp_ev * tx_per_ev, n_xdp_ev);
223 	} else {
224 		efx->n_xdp_channels = 0;
225 		efx->xdp_tx_per_channel = 0;
226 		efx->xdp_tx_queue_count = n_xdp_tx;
227 	}
228 
229 	if (vec_count < n_channels) {
230 		netif_err(efx, drv, efx->net_dev,
231 			  "WARNING: Insufficient MSI-X vectors available (%d < %u).\n",
232 			  vec_count, n_channels);
233 		netif_err(efx, drv, efx->net_dev,
234 			  "WARNING: Performance may be reduced.\n");
235 		n_channels = vec_count;
236 	}
237 
238 	n_channels = min(n_channels, max_channels);
239 
240 	efx->n_channels = n_channels;
241 
242 	/* Ignore XDP tx channels when creating rx channels. */
243 	n_channels -= efx->n_xdp_channels;
244 
245 	if (efx_separate_tx_channels) {
246 		efx->n_tx_channels =
247 			min(max(n_channels / 2, 1U),
248 			    efx->max_tx_channels);
249 		efx->tx_channel_offset =
250 			n_channels - efx->n_tx_channels;
251 		efx->n_rx_channels =
252 			max(n_channels -
253 			    efx->n_tx_channels, 1U);
254 	} else {
255 		efx->n_tx_channels = min(n_channels, efx->max_tx_channels);
256 		efx->tx_channel_offset = 0;
257 		efx->n_rx_channels = n_channels;
258 	}
259 
260 	efx->n_rx_channels = min(efx->n_rx_channels, parallelism);
261 	efx->n_tx_channels = min(efx->n_tx_channels, parallelism);
262 
263 	efx->xdp_channel_offset = n_channels;
264 
265 	netif_dbg(efx, drv, efx->net_dev,
266 		  "Allocating %u RX channels\n",
267 		  efx->n_rx_channels);
268 
269 	return efx->n_channels;
270 }
271 
272 /* Probe the number and type of interrupts we are able to obtain, and
273  * the resulting numbers of channels and RX queues.
274  */
275 int efx_probe_interrupts(struct efx_nic *efx)
276 {
277 	unsigned int extra_channels = 0;
278 	unsigned int rss_spread;
279 	unsigned int i, j;
280 	int rc;
281 
282 	for (i = 0; i < EFX_MAX_EXTRA_CHANNELS; i++)
283 		if (efx->extra_channel_type[i])
284 			++extra_channels;
285 
286 	if (efx->interrupt_mode == EFX_INT_MODE_MSIX) {
287 		unsigned int parallelism = efx_wanted_parallelism(efx);
288 		struct msix_entry xentries[EFX_MAX_CHANNELS];
289 		unsigned int n_channels;
290 
291 		rc = efx_allocate_msix_channels(efx, efx->max_channels,
292 						extra_channels, parallelism);
293 		if (rc >= 0) {
294 			n_channels = rc;
295 			for (i = 0; i < n_channels; i++)
296 				xentries[i].entry = i;
297 			rc = pci_enable_msix_range(efx->pci_dev, xentries, 1,
298 						   n_channels);
299 		}
300 		if (rc < 0) {
301 			/* Fall back to single channel MSI */
302 			netif_err(efx, drv, efx->net_dev,
303 				  "could not enable MSI-X\n");
304 			if (efx->type->min_interrupt_mode >= EFX_INT_MODE_MSI)
305 				efx->interrupt_mode = EFX_INT_MODE_MSI;
306 			else
307 				return rc;
308 		} else if (rc < n_channels) {
309 			netif_err(efx, drv, efx->net_dev,
310 				  "WARNING: Insufficient MSI-X vectors"
311 				  " available (%d < %u).\n", rc, n_channels);
312 			netif_err(efx, drv, efx->net_dev,
313 				  "WARNING: Performance may be reduced.\n");
314 			n_channels = rc;
315 		}
316 
317 		if (rc > 0) {
318 			for (i = 0; i < efx->n_channels; i++)
319 				efx_get_channel(efx, i)->irq =
320 					xentries[i].vector;
321 		}
322 	}
323 
324 	/* Try single interrupt MSI */
325 	if (efx->interrupt_mode == EFX_INT_MODE_MSI) {
326 		efx->n_channels = 1;
327 		efx->n_rx_channels = 1;
328 		efx->n_tx_channels = 1;
329 		efx->n_xdp_channels = 0;
330 		efx->xdp_channel_offset = efx->n_channels;
331 		rc = pci_enable_msi(efx->pci_dev);
332 		if (rc == 0) {
333 			efx_get_channel(efx, 0)->irq = efx->pci_dev->irq;
334 		} else {
335 			netif_err(efx, drv, efx->net_dev,
336 				  "could not enable MSI\n");
337 			if (efx->type->min_interrupt_mode >= EFX_INT_MODE_LEGACY)
338 				efx->interrupt_mode = EFX_INT_MODE_LEGACY;
339 			else
340 				return rc;
341 		}
342 	}
343 
344 	/* Assume legacy interrupts */
345 	if (efx->interrupt_mode == EFX_INT_MODE_LEGACY) {
346 		efx->n_channels = 1 + (efx_separate_tx_channels ? 1 : 0);
347 		efx->n_rx_channels = 1;
348 		efx->n_tx_channels = 1;
349 		efx->n_xdp_channels = 0;
350 		efx->xdp_channel_offset = efx->n_channels;
351 		efx->legacy_irq = efx->pci_dev->irq;
352 	}
353 
354 	/* Assign extra channels if possible, before XDP channels */
355 	efx->n_extra_tx_channels = 0;
356 	j = efx->xdp_channel_offset;
357 	for (i = 0; i < EFX_MAX_EXTRA_CHANNELS; i++) {
358 		if (!efx->extra_channel_type[i])
359 			continue;
360 		if (j <= efx->tx_channel_offset + efx->n_tx_channels) {
361 			efx->extra_channel_type[i]->handle_no_channel(efx);
362 		} else {
363 			--j;
364 			efx_get_channel(efx, j)->type =
365 				efx->extra_channel_type[i];
366 			if (efx_channel_has_tx_queues(efx_get_channel(efx, j)))
367 				efx->n_extra_tx_channels++;
368 		}
369 	}
370 
371 	rss_spread = efx->n_rx_channels;
372 	/* RSS might be usable on VFs even if it is disabled on the PF */
373 #ifdef CONFIG_SFC_SRIOV
374 	if (efx->type->sriov_wanted) {
375 		efx->rss_spread = ((rss_spread > 1 ||
376 				    !efx->type->sriov_wanted(efx)) ?
377 				   rss_spread : efx_vf_size(efx));
378 		return 0;
379 	}
380 #endif
381 	efx->rss_spread = rss_spread;
382 
383 	return 0;
384 }
385 
386 #if defined(CONFIG_SMP)
387 void efx_set_interrupt_affinity(struct efx_nic *efx)
388 {
389 	int numa_node = pcibus_to_node(efx->pci_dev->bus);
390 	const struct cpumask *numa_mask = cpumask_of_node(numa_node);
391 	struct efx_channel *channel;
392 	unsigned int cpu;
393 
394 	/* If no online CPUs in local node, fallback to any online CPU */
395 	if (cpumask_first_and(cpu_online_mask, numa_mask) >= nr_cpu_ids)
396 		numa_mask = cpu_online_mask;
397 
398 	cpu = -1;
399 	efx_for_each_channel(channel, efx) {
400 		cpu = cpumask_next_and(cpu, cpu_online_mask, numa_mask);
401 		if (cpu >= nr_cpu_ids)
402 			cpu = cpumask_first_and(cpu_online_mask, numa_mask);
403 		irq_set_affinity_hint(channel->irq, cpumask_of(cpu));
404 	}
405 }
406 
407 void efx_clear_interrupt_affinity(struct efx_nic *efx)
408 {
409 	struct efx_channel *channel;
410 
411 	efx_for_each_channel(channel, efx)
412 		irq_set_affinity_hint(channel->irq, NULL);
413 }
414 #else
415 void
416 efx_set_interrupt_affinity(struct efx_nic *efx __attribute__ ((unused)))
417 {
418 }
419 
420 void
421 efx_clear_interrupt_affinity(struct efx_nic *efx __attribute__ ((unused)))
422 {
423 }
424 #endif /* CONFIG_SMP */
425 
426 void efx_remove_interrupts(struct efx_nic *efx)
427 {
428 	struct efx_channel *channel;
429 
430 	/* Remove MSI/MSI-X interrupts */
431 	efx_for_each_channel(channel, efx)
432 		channel->irq = 0;
433 	pci_disable_msi(efx->pci_dev);
434 	pci_disable_msix(efx->pci_dev);
435 
436 	/* Remove legacy interrupt */
437 	efx->legacy_irq = 0;
438 }
439 
440 /***************
441  * EVENT QUEUES
442  ***************/
443 
444 /* Create event queue
445  * Event queue memory allocations are done only once.  If the channel
446  * is reset, the memory buffer will be reused; this guards against
447  * errors during channel reset and also simplifies interrupt handling.
448  */
449 int efx_probe_eventq(struct efx_channel *channel)
450 {
451 	struct efx_nic *efx = channel->efx;
452 	unsigned long entries;
453 
454 	netif_dbg(efx, probe, efx->net_dev,
455 		  "chan %d create event queue\n", channel->channel);
456 
457 	/* Build an event queue with room for one event per tx and rx buffer,
458 	 * plus some extra for link state events and MCDI completions.
459 	 */
460 	entries = roundup_pow_of_two(efx->rxq_entries + efx->txq_entries + 128);
461 	EFX_WARN_ON_PARANOID(entries > EFX_MAX_EVQ_SIZE);
462 	channel->eventq_mask = max(entries, EFX_MIN_EVQ_SIZE) - 1;
463 
464 	return efx_nic_probe_eventq(channel);
465 }
466 
467 /* Prepare channel's event queue */
468 int efx_init_eventq(struct efx_channel *channel)
469 {
470 	struct efx_nic *efx = channel->efx;
471 	int rc;
472 
473 	EFX_WARN_ON_PARANOID(channel->eventq_init);
474 
475 	netif_dbg(efx, drv, efx->net_dev,
476 		  "chan %d init event queue\n", channel->channel);
477 
478 	rc = efx_nic_init_eventq(channel);
479 	if (rc == 0) {
480 		efx->type->push_irq_moderation(channel);
481 		channel->eventq_read_ptr = 0;
482 		channel->eventq_init = true;
483 	}
484 	return rc;
485 }
486 
487 /* Enable event queue processing and NAPI */
488 void efx_start_eventq(struct efx_channel *channel)
489 {
490 	netif_dbg(channel->efx, ifup, channel->efx->net_dev,
491 		  "chan %d start event queue\n", channel->channel);
492 
493 	/* Make sure the NAPI handler sees the enabled flag set */
494 	channel->enabled = true;
495 	smp_wmb();
496 
497 	napi_enable(&channel->napi_str);
498 	efx_nic_eventq_read_ack(channel);
499 }
500 
501 /* Disable event queue processing and NAPI */
502 void efx_stop_eventq(struct efx_channel *channel)
503 {
504 	if (!channel->enabled)
505 		return;
506 
507 	napi_disable(&channel->napi_str);
508 	channel->enabled = false;
509 }
510 
511 void efx_fini_eventq(struct efx_channel *channel)
512 {
513 	if (!channel->eventq_init)
514 		return;
515 
516 	netif_dbg(channel->efx, drv, channel->efx->net_dev,
517 		  "chan %d fini event queue\n", channel->channel);
518 
519 	efx_nic_fini_eventq(channel);
520 	channel->eventq_init = false;
521 }
522 
523 void efx_remove_eventq(struct efx_channel *channel)
524 {
525 	netif_dbg(channel->efx, drv, channel->efx->net_dev,
526 		  "chan %d remove event queue\n", channel->channel);
527 
528 	efx_nic_remove_eventq(channel);
529 }
530 
531 /**************************************************************************
532  *
533  * Channel handling
534  *
535  *************************************************************************/
536 
537 #ifdef CONFIG_RFS_ACCEL
538 static void efx_filter_rfs_expire(struct work_struct *data)
539 {
540 	struct delayed_work *dwork = to_delayed_work(data);
541 	struct efx_channel *channel;
542 	unsigned int time, quota;
543 
544 	channel = container_of(dwork, struct efx_channel, filter_work);
545 	time = jiffies - channel->rfs_last_expiry;
546 	quota = channel->rfs_filter_count * time / (30 * HZ);
547 	if (quota >= 20 && __efx_filter_rfs_expire(channel, min(channel->rfs_filter_count, quota)))
548 		channel->rfs_last_expiry += time;
549 	/* Ensure we do more work eventually even if NAPI poll is not happening */
550 	schedule_delayed_work(dwork, 30 * HZ);
551 }
552 #endif
553 
554 /* Allocate and initialise a channel structure. */
555 static struct efx_channel *efx_alloc_channel(struct efx_nic *efx, int i)
556 {
557 	struct efx_rx_queue *rx_queue;
558 	struct efx_tx_queue *tx_queue;
559 	struct efx_channel *channel;
560 	int j;
561 
562 	channel = kzalloc(sizeof(*channel), GFP_KERNEL);
563 	if (!channel)
564 		return NULL;
565 
566 	channel->efx = efx;
567 	channel->channel = i;
568 	channel->type = &efx_default_channel_type;
569 
570 	for (j = 0; j < EFX_MAX_TXQ_PER_CHANNEL; j++) {
571 		tx_queue = &channel->tx_queue[j];
572 		tx_queue->efx = efx;
573 		tx_queue->queue = -1;
574 		tx_queue->label = j;
575 		tx_queue->channel = channel;
576 	}
577 
578 #ifdef CONFIG_RFS_ACCEL
579 	INIT_DELAYED_WORK(&channel->filter_work, efx_filter_rfs_expire);
580 #endif
581 
582 	rx_queue = &channel->rx_queue;
583 	rx_queue->efx = efx;
584 	timer_setup(&rx_queue->slow_fill, efx_rx_slow_fill, 0);
585 
586 	return channel;
587 }
588 
589 int efx_init_channels(struct efx_nic *efx)
590 {
591 	unsigned int i;
592 
593 	for (i = 0; i < EFX_MAX_CHANNELS; i++) {
594 		efx->channel[i] = efx_alloc_channel(efx, i);
595 		if (!efx->channel[i])
596 			return -ENOMEM;
597 		efx->msi_context[i].efx = efx;
598 		efx->msi_context[i].index = i;
599 	}
600 
601 	/* Higher numbered interrupt modes are less capable! */
602 	efx->interrupt_mode = min(efx->type->min_interrupt_mode,
603 				  efx_interrupt_mode);
604 
605 	efx->max_channels = EFX_MAX_CHANNELS;
606 	efx->max_tx_channels = EFX_MAX_CHANNELS;
607 
608 	return 0;
609 }
610 
611 void efx_fini_channels(struct efx_nic *efx)
612 {
613 	unsigned int i;
614 
615 	for (i = 0; i < EFX_MAX_CHANNELS; i++)
616 		if (efx->channel[i]) {
617 			kfree(efx->channel[i]);
618 			efx->channel[i] = NULL;
619 		}
620 }
621 
622 /* Allocate and initialise a channel structure, copying parameters
623  * (but not resources) from an old channel structure.
624  */
625 struct efx_channel *efx_copy_channel(const struct efx_channel *old_channel)
626 {
627 	struct efx_rx_queue *rx_queue;
628 	struct efx_tx_queue *tx_queue;
629 	struct efx_channel *channel;
630 	int j;
631 
632 	channel = kmalloc(sizeof(*channel), GFP_KERNEL);
633 	if (!channel)
634 		return NULL;
635 
636 	*channel = *old_channel;
637 
638 	channel->napi_dev = NULL;
639 	INIT_HLIST_NODE(&channel->napi_str.napi_hash_node);
640 	channel->napi_str.napi_id = 0;
641 	channel->napi_str.state = 0;
642 	memset(&channel->eventq, 0, sizeof(channel->eventq));
643 
644 	for (j = 0; j < EFX_MAX_TXQ_PER_CHANNEL; j++) {
645 		tx_queue = &channel->tx_queue[j];
646 		if (tx_queue->channel)
647 			tx_queue->channel = channel;
648 		tx_queue->buffer = NULL;
649 		tx_queue->cb_page = NULL;
650 		memset(&tx_queue->txd, 0, sizeof(tx_queue->txd));
651 	}
652 
653 	rx_queue = &channel->rx_queue;
654 	rx_queue->buffer = NULL;
655 	memset(&rx_queue->rxd, 0, sizeof(rx_queue->rxd));
656 	timer_setup(&rx_queue->slow_fill, efx_rx_slow_fill, 0);
657 #ifdef CONFIG_RFS_ACCEL
658 	INIT_DELAYED_WORK(&channel->filter_work, efx_filter_rfs_expire);
659 #endif
660 
661 	return channel;
662 }
663 
664 static int efx_probe_channel(struct efx_channel *channel)
665 {
666 	struct efx_tx_queue *tx_queue;
667 	struct efx_rx_queue *rx_queue;
668 	int rc;
669 
670 	netif_dbg(channel->efx, probe, channel->efx->net_dev,
671 		  "creating channel %d\n", channel->channel);
672 
673 	rc = channel->type->pre_probe(channel);
674 	if (rc)
675 		goto fail;
676 
677 	rc = efx_probe_eventq(channel);
678 	if (rc)
679 		goto fail;
680 
681 	efx_for_each_channel_tx_queue(tx_queue, channel) {
682 		rc = efx_probe_tx_queue(tx_queue);
683 		if (rc)
684 			goto fail;
685 	}
686 
687 	efx_for_each_channel_rx_queue(rx_queue, channel) {
688 		rc = efx_probe_rx_queue(rx_queue);
689 		if (rc)
690 			goto fail;
691 	}
692 
693 	channel->rx_list = NULL;
694 
695 	return 0;
696 
697 fail:
698 	efx_remove_channel(channel);
699 	return rc;
700 }
701 
702 void efx_get_channel_name(struct efx_channel *channel, char *buf, size_t len)
703 {
704 	struct efx_nic *efx = channel->efx;
705 	const char *type;
706 	int number;
707 
708 	number = channel->channel;
709 
710 	if (number >= efx->xdp_channel_offset &&
711 	    !WARN_ON_ONCE(!efx->n_xdp_channels)) {
712 		type = "-xdp";
713 		number -= efx->xdp_channel_offset;
714 	} else if (efx->tx_channel_offset == 0) {
715 		type = "";
716 	} else if (number < efx->tx_channel_offset) {
717 		type = "-rx";
718 	} else {
719 		type = "-tx";
720 		number -= efx->tx_channel_offset;
721 	}
722 	snprintf(buf, len, "%s%s-%d", efx->name, type, number);
723 }
724 
725 void efx_set_channel_names(struct efx_nic *efx)
726 {
727 	struct efx_channel *channel;
728 
729 	efx_for_each_channel(channel, efx)
730 		channel->type->get_name(channel,
731 					efx->msi_context[channel->channel].name,
732 					sizeof(efx->msi_context[0].name));
733 }
734 
735 int efx_probe_channels(struct efx_nic *efx)
736 {
737 	struct efx_channel *channel;
738 	int rc;
739 
740 	/* Restart special buffer allocation */
741 	efx->next_buffer_table = 0;
742 
743 	/* Probe channels in reverse, so that any 'extra' channels
744 	 * use the start of the buffer table. This allows the traffic
745 	 * channels to be resized without moving them or wasting the
746 	 * entries before them.
747 	 */
748 	efx_for_each_channel_rev(channel, efx) {
749 		rc = efx_probe_channel(channel);
750 		if (rc) {
751 			netif_err(efx, probe, efx->net_dev,
752 				  "failed to create channel %d\n",
753 				  channel->channel);
754 			goto fail;
755 		}
756 	}
757 	efx_set_channel_names(efx);
758 
759 	return 0;
760 
761 fail:
762 	efx_remove_channels(efx);
763 	return rc;
764 }
765 
766 void efx_remove_channel(struct efx_channel *channel)
767 {
768 	struct efx_tx_queue *tx_queue;
769 	struct efx_rx_queue *rx_queue;
770 
771 	netif_dbg(channel->efx, drv, channel->efx->net_dev,
772 		  "destroy chan %d\n", channel->channel);
773 
774 	efx_for_each_channel_rx_queue(rx_queue, channel)
775 		efx_remove_rx_queue(rx_queue);
776 	efx_for_each_channel_tx_queue(tx_queue, channel)
777 		efx_remove_tx_queue(tx_queue);
778 	efx_remove_eventq(channel);
779 	channel->type->post_remove(channel);
780 }
781 
782 void efx_remove_channels(struct efx_nic *efx)
783 {
784 	struct efx_channel *channel;
785 
786 	efx_for_each_channel(channel, efx)
787 		efx_remove_channel(channel);
788 
789 	kfree(efx->xdp_tx_queues);
790 }
791 
792 int efx_realloc_channels(struct efx_nic *efx, u32 rxq_entries, u32 txq_entries)
793 {
794 	struct efx_channel *other_channel[EFX_MAX_CHANNELS], *channel;
795 	unsigned int i, next_buffer_table = 0;
796 	u32 old_rxq_entries, old_txq_entries;
797 	int rc, rc2;
798 
799 	rc = efx_check_disabled(efx);
800 	if (rc)
801 		return rc;
802 
803 	/* Not all channels should be reallocated. We must avoid
804 	 * reallocating their buffer table entries.
805 	 */
806 	efx_for_each_channel(channel, efx) {
807 		struct efx_rx_queue *rx_queue;
808 		struct efx_tx_queue *tx_queue;
809 
810 		if (channel->type->copy)
811 			continue;
812 		next_buffer_table = max(next_buffer_table,
813 					channel->eventq.index +
814 					channel->eventq.entries);
815 		efx_for_each_channel_rx_queue(rx_queue, channel)
816 			next_buffer_table = max(next_buffer_table,
817 						rx_queue->rxd.index +
818 						rx_queue->rxd.entries);
819 		efx_for_each_channel_tx_queue(tx_queue, channel)
820 			next_buffer_table = max(next_buffer_table,
821 						tx_queue->txd.index +
822 						tx_queue->txd.entries);
823 	}
824 
825 	efx_device_detach_sync(efx);
826 	efx_stop_all(efx);
827 	efx_soft_disable_interrupts(efx);
828 
829 	/* Clone channels (where possible) */
830 	memset(other_channel, 0, sizeof(other_channel));
831 	for (i = 0; i < efx->n_channels; i++) {
832 		channel = efx->channel[i];
833 		if (channel->type->copy)
834 			channel = channel->type->copy(channel);
835 		if (!channel) {
836 			rc = -ENOMEM;
837 			goto out;
838 		}
839 		other_channel[i] = channel;
840 	}
841 
842 	/* Swap entry counts and channel pointers */
843 	old_rxq_entries = efx->rxq_entries;
844 	old_txq_entries = efx->txq_entries;
845 	efx->rxq_entries = rxq_entries;
846 	efx->txq_entries = txq_entries;
847 	for (i = 0; i < efx->n_channels; i++)
848 		swap(efx->channel[i], other_channel[i]);
849 
850 	/* Restart buffer table allocation */
851 	efx->next_buffer_table = next_buffer_table;
852 
853 	for (i = 0; i < efx->n_channels; i++) {
854 		channel = efx->channel[i];
855 		if (!channel->type->copy)
856 			continue;
857 		rc = efx_probe_channel(channel);
858 		if (rc)
859 			goto rollback;
860 		efx_init_napi_channel(efx->channel[i]);
861 	}
862 
863 out:
864 	/* Destroy unused channel structures */
865 	for (i = 0; i < efx->n_channels; i++) {
866 		channel = other_channel[i];
867 		if (channel && channel->type->copy) {
868 			efx_fini_napi_channel(channel);
869 			efx_remove_channel(channel);
870 			kfree(channel);
871 		}
872 	}
873 
874 	rc2 = efx_soft_enable_interrupts(efx);
875 	if (rc2) {
876 		rc = rc ? rc : rc2;
877 		netif_err(efx, drv, efx->net_dev,
878 			  "unable to restart interrupts on channel reallocation\n");
879 		efx_schedule_reset(efx, RESET_TYPE_DISABLE);
880 	} else {
881 		efx_start_all(efx);
882 		efx_device_attach_if_not_resetting(efx);
883 	}
884 	return rc;
885 
886 rollback:
887 	/* Swap back */
888 	efx->rxq_entries = old_rxq_entries;
889 	efx->txq_entries = old_txq_entries;
890 	for (i = 0; i < efx->n_channels; i++)
891 		swap(efx->channel[i], other_channel[i]);
892 	goto out;
893 }
894 
895 static inline int
896 efx_set_xdp_tx_queue(struct efx_nic *efx, int xdp_queue_number,
897 		     struct efx_tx_queue *tx_queue)
898 {
899 	if (xdp_queue_number >= efx->xdp_tx_queue_count)
900 		return -EINVAL;
901 
902 	netif_dbg(efx, drv, efx->net_dev, "Channel %u TXQ %u is XDP %u, HW %u\n",
903 		  tx_queue->channel->channel, tx_queue->label,
904 		  xdp_queue_number, tx_queue->queue);
905 	efx->xdp_tx_queues[xdp_queue_number] = tx_queue;
906 	return 0;
907 }
908 
909 int efx_set_channels(struct efx_nic *efx)
910 {
911 	struct efx_tx_queue *tx_queue;
912 	struct efx_channel *channel;
913 	unsigned int next_queue = 0;
914 	int xdp_queue_number;
915 	int rc;
916 
917 	efx->tx_channel_offset =
918 		efx_separate_tx_channels ?
919 		efx->n_channels - efx->n_tx_channels : 0;
920 
921 	if (efx->xdp_tx_queue_count) {
922 		EFX_WARN_ON_PARANOID(efx->xdp_tx_queues);
923 
924 		/* Allocate array for XDP TX queue lookup. */
925 		efx->xdp_tx_queues = kcalloc(efx->xdp_tx_queue_count,
926 					     sizeof(*efx->xdp_tx_queues),
927 					     GFP_KERNEL);
928 		if (!efx->xdp_tx_queues)
929 			return -ENOMEM;
930 	}
931 
932 	/* We need to mark which channels really have RX and TX
933 	 * queues, and adjust the TX queue numbers if we have separate
934 	 * RX-only and TX-only channels.
935 	 */
936 	xdp_queue_number = 0;
937 	efx_for_each_channel(channel, efx) {
938 		if (channel->channel < efx->n_rx_channels)
939 			channel->rx_queue.core_index = channel->channel;
940 		else
941 			channel->rx_queue.core_index = -1;
942 
943 		if (channel->channel >= efx->tx_channel_offset) {
944 			if (efx_channel_is_xdp_tx(channel)) {
945 				efx_for_each_channel_tx_queue(tx_queue, channel) {
946 					tx_queue->queue = next_queue++;
947 					rc = efx_set_xdp_tx_queue(efx, xdp_queue_number, tx_queue);
948 					if (rc == 0)
949 						xdp_queue_number++;
950 				}
951 			} else {
952 				efx_for_each_channel_tx_queue(tx_queue, channel) {
953 					tx_queue->queue = next_queue++;
954 					netif_dbg(efx, drv, efx->net_dev, "Channel %u TXQ %u is HW %u\n",
955 						  channel->channel, tx_queue->label,
956 						  tx_queue->queue);
957 				}
958 
959 				/* If XDP is borrowing queues from net stack, it must use the queue
960 				 * with no csum offload, which is the first one of the channel
961 				 * (note: channel->tx_queue_by_type is not initialized yet)
962 				 */
963 				if (efx->xdp_txq_queues_mode == EFX_XDP_TX_QUEUES_BORROWED) {
964 					tx_queue = &channel->tx_queue[0];
965 					rc = efx_set_xdp_tx_queue(efx, xdp_queue_number, tx_queue);
966 					if (rc == 0)
967 						xdp_queue_number++;
968 				}
969 			}
970 		}
971 	}
972 	WARN_ON(efx->xdp_txq_queues_mode == EFX_XDP_TX_QUEUES_DEDICATED &&
973 		xdp_queue_number != efx->xdp_tx_queue_count);
974 	WARN_ON(efx->xdp_txq_queues_mode != EFX_XDP_TX_QUEUES_DEDICATED &&
975 		xdp_queue_number > efx->xdp_tx_queue_count);
976 
977 	/* If we have more CPUs than assigned XDP TX queues, assign the already
978 	 * existing queues to the exceeding CPUs
979 	 */
980 	next_queue = 0;
981 	while (xdp_queue_number < efx->xdp_tx_queue_count) {
982 		tx_queue = efx->xdp_tx_queues[next_queue++];
983 		rc = efx_set_xdp_tx_queue(efx, xdp_queue_number, tx_queue);
984 		if (rc == 0)
985 			xdp_queue_number++;
986 	}
987 
988 	rc = netif_set_real_num_tx_queues(efx->net_dev, efx->n_tx_channels);
989 	if (rc)
990 		return rc;
991 	return netif_set_real_num_rx_queues(efx->net_dev, efx->n_rx_channels);
992 }
993 
994 bool efx_default_channel_want_txqs(struct efx_channel *channel)
995 {
996 	return channel->channel - channel->efx->tx_channel_offset <
997 		channel->efx->n_tx_channels;
998 }
999 
1000 /*************
1001  * START/STOP
1002  *************/
1003 
1004 int efx_soft_enable_interrupts(struct efx_nic *efx)
1005 {
1006 	struct efx_channel *channel, *end_channel;
1007 	int rc;
1008 
1009 	BUG_ON(efx->state == STATE_DISABLED);
1010 
1011 	efx->irq_soft_enabled = true;
1012 	smp_wmb();
1013 
1014 	efx_for_each_channel(channel, efx) {
1015 		if (!channel->type->keep_eventq) {
1016 			rc = efx_init_eventq(channel);
1017 			if (rc)
1018 				goto fail;
1019 		}
1020 		efx_start_eventq(channel);
1021 	}
1022 
1023 	efx_mcdi_mode_event(efx);
1024 
1025 	return 0;
1026 fail:
1027 	end_channel = channel;
1028 	efx_for_each_channel(channel, efx) {
1029 		if (channel == end_channel)
1030 			break;
1031 		efx_stop_eventq(channel);
1032 		if (!channel->type->keep_eventq)
1033 			efx_fini_eventq(channel);
1034 	}
1035 
1036 	return rc;
1037 }
1038 
1039 void efx_soft_disable_interrupts(struct efx_nic *efx)
1040 {
1041 	struct efx_channel *channel;
1042 
1043 	if (efx->state == STATE_DISABLED)
1044 		return;
1045 
1046 	efx_mcdi_mode_poll(efx);
1047 
1048 	efx->irq_soft_enabled = false;
1049 	smp_wmb();
1050 
1051 	if (efx->legacy_irq)
1052 		synchronize_irq(efx->legacy_irq);
1053 
1054 	efx_for_each_channel(channel, efx) {
1055 		if (channel->irq)
1056 			synchronize_irq(channel->irq);
1057 
1058 		efx_stop_eventq(channel);
1059 		if (!channel->type->keep_eventq)
1060 			efx_fini_eventq(channel);
1061 	}
1062 
1063 	/* Flush the asynchronous MCDI request queue */
1064 	efx_mcdi_flush_async(efx);
1065 }
1066 
1067 int efx_enable_interrupts(struct efx_nic *efx)
1068 {
1069 	struct efx_channel *channel, *end_channel;
1070 	int rc;
1071 
1072 	/* TODO: Is this really a bug? */
1073 	BUG_ON(efx->state == STATE_DISABLED);
1074 
1075 	if (efx->eeh_disabled_legacy_irq) {
1076 		enable_irq(efx->legacy_irq);
1077 		efx->eeh_disabled_legacy_irq = false;
1078 	}
1079 
1080 	efx->type->irq_enable_master(efx);
1081 
1082 	efx_for_each_channel(channel, efx) {
1083 		if (channel->type->keep_eventq) {
1084 			rc = efx_init_eventq(channel);
1085 			if (rc)
1086 				goto fail;
1087 		}
1088 	}
1089 
1090 	rc = efx_soft_enable_interrupts(efx);
1091 	if (rc)
1092 		goto fail;
1093 
1094 	return 0;
1095 
1096 fail:
1097 	end_channel = channel;
1098 	efx_for_each_channel(channel, efx) {
1099 		if (channel == end_channel)
1100 			break;
1101 		if (channel->type->keep_eventq)
1102 			efx_fini_eventq(channel);
1103 	}
1104 
1105 	efx->type->irq_disable_non_ev(efx);
1106 
1107 	return rc;
1108 }
1109 
1110 void efx_disable_interrupts(struct efx_nic *efx)
1111 {
1112 	struct efx_channel *channel;
1113 
1114 	efx_soft_disable_interrupts(efx);
1115 
1116 	efx_for_each_channel(channel, efx) {
1117 		if (channel->type->keep_eventq)
1118 			efx_fini_eventq(channel);
1119 	}
1120 
1121 	efx->type->irq_disable_non_ev(efx);
1122 }
1123 
1124 void efx_start_channels(struct efx_nic *efx)
1125 {
1126 	struct efx_tx_queue *tx_queue;
1127 	struct efx_rx_queue *rx_queue;
1128 	struct efx_channel *channel;
1129 
1130 	efx_for_each_channel(channel, efx) {
1131 		efx_for_each_channel_tx_queue(tx_queue, channel) {
1132 			efx_init_tx_queue(tx_queue);
1133 			atomic_inc(&efx->active_queues);
1134 		}
1135 
1136 		efx_for_each_channel_rx_queue(rx_queue, channel) {
1137 			efx_init_rx_queue(rx_queue);
1138 			atomic_inc(&efx->active_queues);
1139 			efx_stop_eventq(channel);
1140 			efx_fast_push_rx_descriptors(rx_queue, false);
1141 			efx_start_eventq(channel);
1142 		}
1143 
1144 		WARN_ON(channel->rx_pkt_n_frags);
1145 	}
1146 }
1147 
1148 void efx_stop_channels(struct efx_nic *efx)
1149 {
1150 	struct efx_tx_queue *tx_queue;
1151 	struct efx_rx_queue *rx_queue;
1152 	struct efx_channel *channel;
1153 	int rc = 0;
1154 
1155 	/* Stop RX refill */
1156 	efx_for_each_channel(channel, efx) {
1157 		efx_for_each_channel_rx_queue(rx_queue, channel)
1158 			rx_queue->refill_enabled = false;
1159 	}
1160 
1161 	efx_for_each_channel(channel, efx) {
1162 		/* RX packet processing is pipelined, so wait for the
1163 		 * NAPI handler to complete.  At least event queue 0
1164 		 * might be kept active by non-data events, so don't
1165 		 * use napi_synchronize() but actually disable NAPI
1166 		 * temporarily.
1167 		 */
1168 		if (efx_channel_has_rx_queue(channel)) {
1169 			efx_stop_eventq(channel);
1170 			efx_start_eventq(channel);
1171 		}
1172 	}
1173 
1174 	if (efx->type->fini_dmaq)
1175 		rc = efx->type->fini_dmaq(efx);
1176 
1177 	if (rc) {
1178 		netif_err(efx, drv, efx->net_dev, "failed to flush queues\n");
1179 	} else {
1180 		netif_dbg(efx, drv, efx->net_dev,
1181 			  "successfully flushed all queues\n");
1182 	}
1183 
1184 	efx_for_each_channel(channel, efx) {
1185 		efx_for_each_channel_rx_queue(rx_queue, channel)
1186 			efx_fini_rx_queue(rx_queue);
1187 		efx_for_each_channel_tx_queue(tx_queue, channel)
1188 			efx_fini_tx_queue(tx_queue);
1189 	}
1190 }
1191 
1192 /**************************************************************************
1193  *
1194  * NAPI interface
1195  *
1196  *************************************************************************/
1197 
1198 /* Process channel's event queue
1199  *
1200  * This function is responsible for processing the event queue of a
1201  * single channel.  The caller must guarantee that this function will
1202  * never be concurrently called more than once on the same channel,
1203  * though different channels may be being processed concurrently.
1204  */
1205 static int efx_process_channel(struct efx_channel *channel, int budget)
1206 {
1207 	struct efx_tx_queue *tx_queue;
1208 	struct list_head rx_list;
1209 	int spent;
1210 
1211 	if (unlikely(!channel->enabled))
1212 		return 0;
1213 
1214 	/* Prepare the batch receive list */
1215 	EFX_WARN_ON_PARANOID(channel->rx_list != NULL);
1216 	INIT_LIST_HEAD(&rx_list);
1217 	channel->rx_list = &rx_list;
1218 
1219 	efx_for_each_channel_tx_queue(tx_queue, channel) {
1220 		tx_queue->pkts_compl = 0;
1221 		tx_queue->bytes_compl = 0;
1222 	}
1223 
1224 	spent = efx_nic_process_eventq(channel, budget);
1225 	if (spent && efx_channel_has_rx_queue(channel)) {
1226 		struct efx_rx_queue *rx_queue =
1227 			efx_channel_get_rx_queue(channel);
1228 
1229 		efx_rx_flush_packet(channel);
1230 		efx_fast_push_rx_descriptors(rx_queue, true);
1231 	}
1232 
1233 	/* Update BQL */
1234 	efx_for_each_channel_tx_queue(tx_queue, channel) {
1235 		if (tx_queue->bytes_compl) {
1236 			netdev_tx_completed_queue(tx_queue->core_txq,
1237 						  tx_queue->pkts_compl,
1238 						  tx_queue->bytes_compl);
1239 		}
1240 	}
1241 
1242 	/* Receive any packets we queued up */
1243 	netif_receive_skb_list(channel->rx_list);
1244 	channel->rx_list = NULL;
1245 
1246 	return spent;
1247 }
1248 
1249 static void efx_update_irq_mod(struct efx_nic *efx, struct efx_channel *channel)
1250 {
1251 	int step = efx->irq_mod_step_us;
1252 
1253 	if (channel->irq_mod_score < irq_adapt_low_thresh) {
1254 		if (channel->irq_moderation_us > step) {
1255 			channel->irq_moderation_us -= step;
1256 			efx->type->push_irq_moderation(channel);
1257 		}
1258 	} else if (channel->irq_mod_score > irq_adapt_high_thresh) {
1259 		if (channel->irq_moderation_us <
1260 		    efx->irq_rx_moderation_us) {
1261 			channel->irq_moderation_us += step;
1262 			efx->type->push_irq_moderation(channel);
1263 		}
1264 	}
1265 
1266 	channel->irq_count = 0;
1267 	channel->irq_mod_score = 0;
1268 }
1269 
1270 /* NAPI poll handler
1271  *
1272  * NAPI guarantees serialisation of polls of the same device, which
1273  * provides the guarantee required by efx_process_channel().
1274  */
1275 static int efx_poll(struct napi_struct *napi, int budget)
1276 {
1277 	struct efx_channel *channel =
1278 		container_of(napi, struct efx_channel, napi_str);
1279 	struct efx_nic *efx = channel->efx;
1280 #ifdef CONFIG_RFS_ACCEL
1281 	unsigned int time;
1282 #endif
1283 	int spent;
1284 
1285 	netif_vdbg(efx, intr, efx->net_dev,
1286 		   "channel %d NAPI poll executing on CPU %d\n",
1287 		   channel->channel, raw_smp_processor_id());
1288 
1289 	spent = efx_process_channel(channel, budget);
1290 
1291 	xdp_do_flush_map();
1292 
1293 	if (spent < budget) {
1294 		if (efx_channel_has_rx_queue(channel) &&
1295 		    efx->irq_rx_adaptive &&
1296 		    unlikely(++channel->irq_count == 1000)) {
1297 			efx_update_irq_mod(efx, channel);
1298 		}
1299 
1300 #ifdef CONFIG_RFS_ACCEL
1301 		/* Perhaps expire some ARFS filters */
1302 		time = jiffies - channel->rfs_last_expiry;
1303 		/* Would our quota be >= 20? */
1304 		if (channel->rfs_filter_count * time >= 600 * HZ)
1305 			mod_delayed_work(system_wq, &channel->filter_work, 0);
1306 #endif
1307 
1308 		/* There is no race here; although napi_disable() will
1309 		 * only wait for napi_complete(), this isn't a problem
1310 		 * since efx_nic_eventq_read_ack() will have no effect if
1311 		 * interrupts have already been disabled.
1312 		 */
1313 		if (napi_complete_done(napi, spent))
1314 			efx_nic_eventq_read_ack(channel);
1315 	}
1316 
1317 	return spent;
1318 }
1319 
1320 void efx_init_napi_channel(struct efx_channel *channel)
1321 {
1322 	struct efx_nic *efx = channel->efx;
1323 
1324 	channel->napi_dev = efx->net_dev;
1325 	netif_napi_add(channel->napi_dev, &channel->napi_str,
1326 		       efx_poll, napi_weight);
1327 }
1328 
1329 void efx_init_napi(struct efx_nic *efx)
1330 {
1331 	struct efx_channel *channel;
1332 
1333 	efx_for_each_channel(channel, efx)
1334 		efx_init_napi_channel(channel);
1335 }
1336 
1337 void efx_fini_napi_channel(struct efx_channel *channel)
1338 {
1339 	if (channel->napi_dev)
1340 		netif_napi_del(&channel->napi_str);
1341 
1342 	channel->napi_dev = NULL;
1343 }
1344 
1345 void efx_fini_napi(struct efx_nic *efx)
1346 {
1347 	struct efx_channel *channel;
1348 
1349 	efx_for_each_channel(channel, efx)
1350 		efx_fini_napi_channel(channel);
1351 }
1352