1 /*
2  * Copyright (c) 2007 Mellanox Technologies. All rights reserved.
3  *
4  * This software is available to you under a choice of one of two
5  * licenses.  You may choose to be licensed under the terms of the GNU
6  * General Public License (GPL) Version 2, available from the file
7  * COPYING in the main directory of this source tree, or the
8  * OpenIB.org BSD license below:
9  *
10  *     Redistribution and use in source and binary forms, with or
11  *     without modification, are permitted provided that the following
12  *     conditions are met:
13  *
14  *      - Redistributions of source code must retain the above
15  *        copyright notice, this list of conditions and the following
16  *        disclaimer.
17  *
18  *      - Redistributions in binary form must reproduce the above
19  *        copyright notice, this list of conditions and the following
20  *        disclaimer in the documentation and/or other materials
21  *        provided with the distribution.
22  *
23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30  * SOFTWARE.
31  *
32  */
33 
34 #include <asm/page.h>
35 #include <linux/mlx4/cq.h>
36 #include <linux/slab.h>
37 #include <linux/mlx4/qp.h>
38 #include <linux/skbuff.h>
39 #include <linux/if_vlan.h>
40 #include <linux/prefetch.h>
41 #include <linux/vmalloc.h>
42 #include <linux/tcp.h>
43 #include <linux/ip.h>
44 #include <linux/ipv6.h>
45 #include <linux/moduleparam.h>
46 
47 #include "mlx4_en.h"
48 
49 int mlx4_en_create_tx_ring(struct mlx4_en_priv *priv,
50 			   struct mlx4_en_tx_ring **pring, u32 size,
51 			   u16 stride, int node, int queue_index)
52 {
53 	struct mlx4_en_dev *mdev = priv->mdev;
54 	struct mlx4_en_tx_ring *ring;
55 	int tmp;
56 	int err;
57 
58 	ring = kzalloc_node(sizeof(*ring), GFP_KERNEL, node);
59 	if (!ring) {
60 		ring = kzalloc(sizeof(*ring), GFP_KERNEL);
61 		if (!ring) {
62 			en_err(priv, "Failed allocating TX ring\n");
63 			return -ENOMEM;
64 		}
65 	}
66 
67 	ring->size = size;
68 	ring->size_mask = size - 1;
69 	ring->sp_stride = stride;
70 	ring->full_size = ring->size - HEADROOM - MAX_DESC_TXBBS;
71 
72 	tmp = size * sizeof(struct mlx4_en_tx_info);
73 	ring->tx_info = kvmalloc_node(tmp, GFP_KERNEL, node);
74 	if (!ring->tx_info) {
75 		err = -ENOMEM;
76 		goto err_ring;
77 	}
78 
79 	en_dbg(DRV, priv, "Allocated tx_info ring at addr:%p size:%d\n",
80 		 ring->tx_info, tmp);
81 
82 	ring->bounce_buf = kmalloc_node(MAX_DESC_SIZE, GFP_KERNEL, node);
83 	if (!ring->bounce_buf) {
84 		ring->bounce_buf = kmalloc(MAX_DESC_SIZE, GFP_KERNEL);
85 		if (!ring->bounce_buf) {
86 			err = -ENOMEM;
87 			goto err_info;
88 		}
89 	}
90 	ring->buf_size = ALIGN(size * ring->sp_stride, MLX4_EN_PAGE_SIZE);
91 
92 	/* Allocate HW buffers on provided NUMA node */
93 	set_dev_node(&mdev->dev->persist->pdev->dev, node);
94 	err = mlx4_alloc_hwq_res(mdev->dev, &ring->sp_wqres, ring->buf_size);
95 	set_dev_node(&mdev->dev->persist->pdev->dev, mdev->dev->numa_node);
96 	if (err) {
97 		en_err(priv, "Failed allocating hwq resources\n");
98 		goto err_bounce;
99 	}
100 
101 	ring->buf = ring->sp_wqres.buf.direct.buf;
102 
103 	en_dbg(DRV, priv, "Allocated TX ring (addr:%p) - buf:%p size:%d buf_size:%d dma:%llx\n",
104 	       ring, ring->buf, ring->size, ring->buf_size,
105 	       (unsigned long long) ring->sp_wqres.buf.direct.map);
106 
107 	err = mlx4_qp_reserve_range(mdev->dev, 1, 1, &ring->qpn,
108 				    MLX4_RESERVE_ETH_BF_QP);
109 	if (err) {
110 		en_err(priv, "failed reserving qp for TX ring\n");
111 		goto err_hwq_res;
112 	}
113 
114 	err = mlx4_qp_alloc(mdev->dev, ring->qpn, &ring->sp_qp, GFP_KERNEL);
115 	if (err) {
116 		en_err(priv, "Failed allocating qp %d\n", ring->qpn);
117 		goto err_reserve;
118 	}
119 	ring->sp_qp.event = mlx4_en_sqp_event;
120 
121 	err = mlx4_bf_alloc(mdev->dev, &ring->bf, node);
122 	if (err) {
123 		en_dbg(DRV, priv, "working without blueflame (%d)\n", err);
124 		ring->bf.uar = &mdev->priv_uar;
125 		ring->bf.uar->map = mdev->uar_map;
126 		ring->bf_enabled = false;
127 		ring->bf_alloced = false;
128 		priv->pflags &= ~MLX4_EN_PRIV_FLAGS_BLUEFLAME;
129 	} else {
130 		ring->bf_alloced = true;
131 		ring->bf_enabled = !!(priv->pflags &
132 				      MLX4_EN_PRIV_FLAGS_BLUEFLAME);
133 	}
134 
135 	ring->hwtstamp_tx_type = priv->hwtstamp_config.tx_type;
136 	ring->queue_index = queue_index;
137 
138 	if (queue_index < priv->num_tx_rings_p_up)
139 		cpumask_set_cpu(cpumask_local_spread(queue_index,
140 						     priv->mdev->dev->numa_node),
141 				&ring->sp_affinity_mask);
142 
143 	*pring = ring;
144 	return 0;
145 
146 err_reserve:
147 	mlx4_qp_release_range(mdev->dev, ring->qpn, 1);
148 err_hwq_res:
149 	mlx4_free_hwq_res(mdev->dev, &ring->sp_wqres, ring->buf_size);
150 err_bounce:
151 	kfree(ring->bounce_buf);
152 	ring->bounce_buf = NULL;
153 err_info:
154 	kvfree(ring->tx_info);
155 	ring->tx_info = NULL;
156 err_ring:
157 	kfree(ring);
158 	*pring = NULL;
159 	return err;
160 }
161 
162 void mlx4_en_destroy_tx_ring(struct mlx4_en_priv *priv,
163 			     struct mlx4_en_tx_ring **pring)
164 {
165 	struct mlx4_en_dev *mdev = priv->mdev;
166 	struct mlx4_en_tx_ring *ring = *pring;
167 	en_dbg(DRV, priv, "Destroying tx ring, qpn: %d\n", ring->qpn);
168 
169 	if (ring->bf_alloced)
170 		mlx4_bf_free(mdev->dev, &ring->bf);
171 	mlx4_qp_remove(mdev->dev, &ring->sp_qp);
172 	mlx4_qp_free(mdev->dev, &ring->sp_qp);
173 	mlx4_qp_release_range(priv->mdev->dev, ring->qpn, 1);
174 	mlx4_free_hwq_res(mdev->dev, &ring->sp_wqres, ring->buf_size);
175 	kfree(ring->bounce_buf);
176 	ring->bounce_buf = NULL;
177 	kvfree(ring->tx_info);
178 	ring->tx_info = NULL;
179 	kfree(ring);
180 	*pring = NULL;
181 }
182 
183 int mlx4_en_activate_tx_ring(struct mlx4_en_priv *priv,
184 			     struct mlx4_en_tx_ring *ring,
185 			     int cq, int user_prio)
186 {
187 	struct mlx4_en_dev *mdev = priv->mdev;
188 	int err;
189 
190 	ring->sp_cqn = cq;
191 	ring->prod = 0;
192 	ring->cons = 0xffffffff;
193 	ring->last_nr_txbb = 1;
194 	memset(ring->tx_info, 0, ring->size * sizeof(struct mlx4_en_tx_info));
195 	memset(ring->buf, 0, ring->buf_size);
196 	ring->free_tx_desc = mlx4_en_free_tx_desc;
197 
198 	ring->sp_qp_state = MLX4_QP_STATE_RST;
199 	ring->doorbell_qpn = cpu_to_be32(ring->sp_qp.qpn << 8);
200 	ring->mr_key = cpu_to_be32(mdev->mr.key);
201 
202 	mlx4_en_fill_qp_context(priv, ring->size, ring->sp_stride, 1, 0, ring->qpn,
203 				ring->sp_cqn, user_prio, &ring->sp_context);
204 	if (ring->bf_alloced)
205 		ring->sp_context.usr_page =
206 			cpu_to_be32(mlx4_to_hw_uar_index(mdev->dev,
207 							 ring->bf.uar->index));
208 
209 	err = mlx4_qp_to_ready(mdev->dev, &ring->sp_wqres.mtt, &ring->sp_context,
210 			       &ring->sp_qp, &ring->sp_qp_state);
211 	if (!cpumask_empty(&ring->sp_affinity_mask))
212 		netif_set_xps_queue(priv->dev, &ring->sp_affinity_mask,
213 				    ring->queue_index);
214 
215 	return err;
216 }
217 
218 void mlx4_en_deactivate_tx_ring(struct mlx4_en_priv *priv,
219 				struct mlx4_en_tx_ring *ring)
220 {
221 	struct mlx4_en_dev *mdev = priv->mdev;
222 
223 	mlx4_qp_modify(mdev->dev, NULL, ring->sp_qp_state,
224 		       MLX4_QP_STATE_RST, NULL, 0, 0, &ring->sp_qp);
225 }
226 
227 static inline bool mlx4_en_is_tx_ring_full(struct mlx4_en_tx_ring *ring)
228 {
229 	return ring->prod - ring->cons > ring->full_size;
230 }
231 
232 static void mlx4_en_stamp_wqe(struct mlx4_en_priv *priv,
233 			      struct mlx4_en_tx_ring *ring, int index,
234 			      u8 owner)
235 {
236 	__be32 stamp = cpu_to_be32(STAMP_VAL | (!!owner << STAMP_SHIFT));
237 	struct mlx4_en_tx_desc *tx_desc = ring->buf + index * TXBB_SIZE;
238 	struct mlx4_en_tx_info *tx_info = &ring->tx_info[index];
239 	void *end = ring->buf + ring->buf_size;
240 	__be32 *ptr = (__be32 *)tx_desc;
241 	int i;
242 
243 	/* Optimize the common case when there are no wraparounds */
244 	if (likely((void *)tx_desc + tx_info->nr_txbb * TXBB_SIZE <= end)) {
245 		/* Stamp the freed descriptor */
246 		for (i = 0; i < tx_info->nr_txbb * TXBB_SIZE;
247 		     i += STAMP_STRIDE) {
248 			*ptr = stamp;
249 			ptr += STAMP_DWORDS;
250 		}
251 	} else {
252 		/* Stamp the freed descriptor */
253 		for (i = 0; i < tx_info->nr_txbb * TXBB_SIZE;
254 		     i += STAMP_STRIDE) {
255 			*ptr = stamp;
256 			ptr += STAMP_DWORDS;
257 			if ((void *)ptr >= end) {
258 				ptr = ring->buf;
259 				stamp ^= cpu_to_be32(0x80000000);
260 			}
261 		}
262 	}
263 }
264 
265 
266 u32 mlx4_en_free_tx_desc(struct mlx4_en_priv *priv,
267 			 struct mlx4_en_tx_ring *ring,
268 			 int index, u8 owner, u64 timestamp,
269 			 int napi_mode)
270 {
271 	struct mlx4_en_tx_info *tx_info = &ring->tx_info[index];
272 	struct mlx4_en_tx_desc *tx_desc = ring->buf + index * TXBB_SIZE;
273 	struct mlx4_wqe_data_seg *data = (void *) tx_desc + tx_info->data_offset;
274 	void *end = ring->buf + ring->buf_size;
275 	struct sk_buff *skb = tx_info->skb;
276 	int nr_maps = tx_info->nr_maps;
277 	int i;
278 
279 	/* We do not touch skb here, so prefetch skb->users location
280 	 * to speedup consume_skb()
281 	 */
282 	prefetchw(&skb->users);
283 
284 	if (unlikely(timestamp)) {
285 		struct skb_shared_hwtstamps hwts;
286 
287 		mlx4_en_fill_hwtstamps(priv->mdev, &hwts, timestamp);
288 		skb_tstamp_tx(skb, &hwts);
289 	}
290 
291 	/* Optimize the common case when there are no wraparounds */
292 	if (likely((void *) tx_desc + tx_info->nr_txbb * TXBB_SIZE <= end)) {
293 		if (!tx_info->inl) {
294 			if (tx_info->linear)
295 				dma_unmap_single(priv->ddev,
296 						tx_info->map0_dma,
297 						tx_info->map0_byte_count,
298 						PCI_DMA_TODEVICE);
299 			else
300 				dma_unmap_page(priv->ddev,
301 					       tx_info->map0_dma,
302 					       tx_info->map0_byte_count,
303 					       PCI_DMA_TODEVICE);
304 			for (i = 1; i < nr_maps; i++) {
305 				data++;
306 				dma_unmap_page(priv->ddev,
307 					(dma_addr_t)be64_to_cpu(data->addr),
308 					be32_to_cpu(data->byte_count),
309 					PCI_DMA_TODEVICE);
310 			}
311 		}
312 	} else {
313 		if (!tx_info->inl) {
314 			if ((void *) data >= end) {
315 				data = ring->buf + ((void *)data - end);
316 			}
317 
318 			if (tx_info->linear)
319 				dma_unmap_single(priv->ddev,
320 						tx_info->map0_dma,
321 						tx_info->map0_byte_count,
322 						PCI_DMA_TODEVICE);
323 			else
324 				dma_unmap_page(priv->ddev,
325 					       tx_info->map0_dma,
326 					       tx_info->map0_byte_count,
327 					       PCI_DMA_TODEVICE);
328 			for (i = 1; i < nr_maps; i++) {
329 				data++;
330 				/* Check for wraparound before unmapping */
331 				if ((void *) data >= end)
332 					data = ring->buf;
333 				dma_unmap_page(priv->ddev,
334 					(dma_addr_t)be64_to_cpu(data->addr),
335 					be32_to_cpu(data->byte_count),
336 					PCI_DMA_TODEVICE);
337 			}
338 		}
339 	}
340 	napi_consume_skb(skb, napi_mode);
341 
342 	return tx_info->nr_txbb;
343 }
344 
345 u32 mlx4_en_recycle_tx_desc(struct mlx4_en_priv *priv,
346 			    struct mlx4_en_tx_ring *ring,
347 			    int index, u8 owner, u64 timestamp,
348 			    int napi_mode)
349 {
350 	struct mlx4_en_tx_info *tx_info = &ring->tx_info[index];
351 	struct mlx4_en_rx_alloc frame = {
352 		.page = tx_info->page,
353 		.dma = tx_info->map0_dma,
354 	};
355 
356 	if (!mlx4_en_rx_recycle(ring->recycle_ring, &frame)) {
357 		dma_unmap_page(priv->ddev, tx_info->map0_dma,
358 			       PAGE_SIZE, priv->dma_dir);
359 		put_page(tx_info->page);
360 	}
361 
362 	return tx_info->nr_txbb;
363 }
364 
365 int mlx4_en_free_tx_buf(struct net_device *dev, struct mlx4_en_tx_ring *ring)
366 {
367 	struct mlx4_en_priv *priv = netdev_priv(dev);
368 	int cnt = 0;
369 
370 	/* Skip last polled descriptor */
371 	ring->cons += ring->last_nr_txbb;
372 	en_dbg(DRV, priv, "Freeing Tx buf - cons:0x%x prod:0x%x\n",
373 		 ring->cons, ring->prod);
374 
375 	if ((u32) (ring->prod - ring->cons) > ring->size) {
376 		if (netif_msg_tx_err(priv))
377 			en_warn(priv, "Tx consumer passed producer!\n");
378 		return 0;
379 	}
380 
381 	while (ring->cons != ring->prod) {
382 		ring->last_nr_txbb = ring->free_tx_desc(priv, ring,
383 						ring->cons & ring->size_mask,
384 						!!(ring->cons & ring->size), 0,
385 						0 /* Non-NAPI caller */);
386 		ring->cons += ring->last_nr_txbb;
387 		cnt++;
388 	}
389 
390 	if (ring->tx_queue)
391 		netdev_tx_reset_queue(ring->tx_queue);
392 
393 	if (cnt)
394 		en_dbg(DRV, priv, "Freed %d uncompleted tx descriptors\n", cnt);
395 
396 	return cnt;
397 }
398 
399 static bool mlx4_en_process_tx_cq(struct net_device *dev,
400 				  struct mlx4_en_cq *cq, int napi_budget)
401 {
402 	struct mlx4_en_priv *priv = netdev_priv(dev);
403 	struct mlx4_cq *mcq = &cq->mcq;
404 	struct mlx4_en_tx_ring *ring = priv->tx_ring[cq->type][cq->ring];
405 	struct mlx4_cqe *cqe;
406 	u16 index;
407 	u16 new_index, ring_index, stamp_index;
408 	u32 txbbs_skipped = 0;
409 	u32 txbbs_stamp = 0;
410 	u32 cons_index = mcq->cons_index;
411 	int size = cq->size;
412 	u32 size_mask = ring->size_mask;
413 	struct mlx4_cqe *buf = cq->buf;
414 	u32 packets = 0;
415 	u32 bytes = 0;
416 	int factor = priv->cqe_factor;
417 	int done = 0;
418 	int budget = priv->tx_work_limit;
419 	u32 last_nr_txbb;
420 	u32 ring_cons;
421 
422 	if (!priv->port_up)
423 		return true;
424 
425 	netdev_txq_bql_complete_prefetchw(ring->tx_queue);
426 
427 	index = cons_index & size_mask;
428 	cqe = mlx4_en_get_cqe(buf, index, priv->cqe_size) + factor;
429 	last_nr_txbb = ACCESS_ONCE(ring->last_nr_txbb);
430 	ring_cons = ACCESS_ONCE(ring->cons);
431 	ring_index = ring_cons & size_mask;
432 	stamp_index = ring_index;
433 
434 	/* Process all completed CQEs */
435 	while (XNOR(cqe->owner_sr_opcode & MLX4_CQE_OWNER_MASK,
436 			cons_index & size) && (done < budget)) {
437 		/*
438 		 * make sure we read the CQE after we read the
439 		 * ownership bit
440 		 */
441 		dma_rmb();
442 
443 		if (unlikely((cqe->owner_sr_opcode & MLX4_CQE_OPCODE_MASK) ==
444 			     MLX4_CQE_OPCODE_ERROR)) {
445 			struct mlx4_err_cqe *cqe_err = (struct mlx4_err_cqe *)cqe;
446 
447 			en_err(priv, "CQE error - vendor syndrome: 0x%x syndrome: 0x%x\n",
448 			       cqe_err->vendor_err_syndrome,
449 			       cqe_err->syndrome);
450 		}
451 
452 		/* Skip over last polled CQE */
453 		new_index = be16_to_cpu(cqe->wqe_index) & size_mask;
454 
455 		do {
456 			u64 timestamp = 0;
457 
458 			txbbs_skipped += last_nr_txbb;
459 			ring_index = (ring_index + last_nr_txbb) & size_mask;
460 
461 			if (unlikely(ring->tx_info[ring_index].ts_requested))
462 				timestamp = mlx4_en_get_cqe_ts(cqe);
463 
464 			/* free next descriptor */
465 			last_nr_txbb = ring->free_tx_desc(
466 					priv, ring, ring_index,
467 					!!((ring_cons + txbbs_skipped) &
468 					ring->size), timestamp, napi_budget);
469 
470 			mlx4_en_stamp_wqe(priv, ring, stamp_index,
471 					  !!((ring_cons + txbbs_stamp) &
472 						ring->size));
473 			stamp_index = ring_index;
474 			txbbs_stamp = txbbs_skipped;
475 			packets++;
476 			bytes += ring->tx_info[ring_index].nr_bytes;
477 		} while ((++done < budget) && (ring_index != new_index));
478 
479 		++cons_index;
480 		index = cons_index & size_mask;
481 		cqe = mlx4_en_get_cqe(buf, index, priv->cqe_size) + factor;
482 	}
483 
484 
485 	/*
486 	 * To prevent CQ overflow we first update CQ consumer and only then
487 	 * the ring consumer.
488 	 */
489 	mcq->cons_index = cons_index;
490 	mlx4_cq_set_ci(mcq);
491 	wmb();
492 
493 	/* we want to dirty this cache line once */
494 	ACCESS_ONCE(ring->last_nr_txbb) = last_nr_txbb;
495 	ACCESS_ONCE(ring->cons) = ring_cons + txbbs_skipped;
496 
497 	if (ring->free_tx_desc == mlx4_en_recycle_tx_desc)
498 		return done < budget;
499 
500 	netdev_tx_completed_queue(ring->tx_queue, packets, bytes);
501 
502 	/* Wakeup Tx queue if this stopped, and ring is not full.
503 	 */
504 	if (netif_tx_queue_stopped(ring->tx_queue) &&
505 	    !mlx4_en_is_tx_ring_full(ring)) {
506 		netif_tx_wake_queue(ring->tx_queue);
507 		ring->wake_queue++;
508 	}
509 	return done < budget;
510 }
511 
512 void mlx4_en_tx_irq(struct mlx4_cq *mcq)
513 {
514 	struct mlx4_en_cq *cq = container_of(mcq, struct mlx4_en_cq, mcq);
515 	struct mlx4_en_priv *priv = netdev_priv(cq->dev);
516 
517 	if (likely(priv->port_up))
518 		napi_schedule_irqoff(&cq->napi);
519 	else
520 		mlx4_en_arm_cq(priv, cq);
521 }
522 
523 /* TX CQ polling - called by NAPI */
524 int mlx4_en_poll_tx_cq(struct napi_struct *napi, int budget)
525 {
526 	struct mlx4_en_cq *cq = container_of(napi, struct mlx4_en_cq, napi);
527 	struct net_device *dev = cq->dev;
528 	struct mlx4_en_priv *priv = netdev_priv(dev);
529 	int clean_complete;
530 
531 	clean_complete = mlx4_en_process_tx_cq(dev, cq, budget);
532 	if (!clean_complete)
533 		return budget;
534 
535 	napi_complete(napi);
536 	mlx4_en_arm_cq(priv, cq);
537 
538 	return 0;
539 }
540 
541 static struct mlx4_en_tx_desc *mlx4_en_bounce_to_desc(struct mlx4_en_priv *priv,
542 						      struct mlx4_en_tx_ring *ring,
543 						      u32 index,
544 						      unsigned int desc_size)
545 {
546 	u32 copy = (ring->size - index) * TXBB_SIZE;
547 	int i;
548 
549 	for (i = desc_size - copy - 4; i >= 0; i -= 4) {
550 		if ((i & (TXBB_SIZE - 1)) == 0)
551 			wmb();
552 
553 		*((u32 *) (ring->buf + i)) =
554 			*((u32 *) (ring->bounce_buf + copy + i));
555 	}
556 
557 	for (i = copy - 4; i >= 4 ; i -= 4) {
558 		if ((i & (TXBB_SIZE - 1)) == 0)
559 			wmb();
560 
561 		*((u32 *) (ring->buf + index * TXBB_SIZE + i)) =
562 			*((u32 *) (ring->bounce_buf + i));
563 	}
564 
565 	/* Return real descriptor location */
566 	return ring->buf + index * TXBB_SIZE;
567 }
568 
569 /* Decide if skb can be inlined in tx descriptor to avoid dma mapping
570  *
571  * It seems strange we do not simply use skb_copy_bits().
572  * This would allow to inline all skbs iff skb->len <= inline_thold
573  *
574  * Note that caller already checked skb was not a gso packet
575  */
576 static bool is_inline(int inline_thold, const struct sk_buff *skb,
577 		      const struct skb_shared_info *shinfo,
578 		      void **pfrag)
579 {
580 	void *ptr;
581 
582 	if (skb->len > inline_thold || !inline_thold)
583 		return false;
584 
585 	if (shinfo->nr_frags == 1) {
586 		ptr = skb_frag_address_safe(&shinfo->frags[0]);
587 		if (unlikely(!ptr))
588 			return false;
589 		*pfrag = ptr;
590 		return true;
591 	}
592 	if (shinfo->nr_frags)
593 		return false;
594 	return true;
595 }
596 
597 static int inline_size(const struct sk_buff *skb)
598 {
599 	if (skb->len + CTRL_SIZE + sizeof(struct mlx4_wqe_inline_seg)
600 	    <= MLX4_INLINE_ALIGN)
601 		return ALIGN(skb->len + CTRL_SIZE +
602 			     sizeof(struct mlx4_wqe_inline_seg), 16);
603 	else
604 		return ALIGN(skb->len + CTRL_SIZE + 2 *
605 			     sizeof(struct mlx4_wqe_inline_seg), 16);
606 }
607 
608 static int get_real_size(const struct sk_buff *skb,
609 			 const struct skb_shared_info *shinfo,
610 			 struct net_device *dev,
611 			 int *lso_header_size,
612 			 bool *inline_ok,
613 			 void **pfrag)
614 {
615 	struct mlx4_en_priv *priv = netdev_priv(dev);
616 	int real_size;
617 
618 	if (shinfo->gso_size) {
619 		*inline_ok = false;
620 		if (skb->encapsulation)
621 			*lso_header_size = (skb_inner_transport_header(skb) - skb->data) + inner_tcp_hdrlen(skb);
622 		else
623 			*lso_header_size = skb_transport_offset(skb) + tcp_hdrlen(skb);
624 		real_size = CTRL_SIZE + shinfo->nr_frags * DS_SIZE +
625 			ALIGN(*lso_header_size + 4, DS_SIZE);
626 		if (unlikely(*lso_header_size != skb_headlen(skb))) {
627 			/* We add a segment for the skb linear buffer only if
628 			 * it contains data */
629 			if (*lso_header_size < skb_headlen(skb))
630 				real_size += DS_SIZE;
631 			else {
632 				if (netif_msg_tx_err(priv))
633 					en_warn(priv, "Non-linear headers\n");
634 				return 0;
635 			}
636 		}
637 	} else {
638 		*lso_header_size = 0;
639 		*inline_ok = is_inline(priv->prof->inline_thold, skb,
640 				       shinfo, pfrag);
641 
642 		if (*inline_ok)
643 			real_size = inline_size(skb);
644 		else
645 			real_size = CTRL_SIZE +
646 				    (shinfo->nr_frags + 1) * DS_SIZE;
647 	}
648 
649 	return real_size;
650 }
651 
652 static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc,
653 			     const struct sk_buff *skb,
654 			     const struct skb_shared_info *shinfo,
655 			     void *fragptr)
656 {
657 	struct mlx4_wqe_inline_seg *inl = &tx_desc->inl;
658 	int spc = MLX4_INLINE_ALIGN - CTRL_SIZE - sizeof *inl;
659 	unsigned int hlen = skb_headlen(skb);
660 
661 	if (skb->len <= spc) {
662 		if (likely(skb->len >= MIN_PKT_LEN)) {
663 			inl->byte_count = cpu_to_be32(1 << 31 | skb->len);
664 		} else {
665 			inl->byte_count = cpu_to_be32(1 << 31 | MIN_PKT_LEN);
666 			memset(((void *)(inl + 1)) + skb->len, 0,
667 			       MIN_PKT_LEN - skb->len);
668 		}
669 		skb_copy_from_linear_data(skb, inl + 1, hlen);
670 		if (shinfo->nr_frags)
671 			memcpy(((void *)(inl + 1)) + hlen, fragptr,
672 			       skb_frag_size(&shinfo->frags[0]));
673 
674 	} else {
675 		inl->byte_count = cpu_to_be32(1 << 31 | spc);
676 		if (hlen <= spc) {
677 			skb_copy_from_linear_data(skb, inl + 1, hlen);
678 			if (hlen < spc) {
679 				memcpy(((void *)(inl + 1)) + hlen,
680 				       fragptr, spc - hlen);
681 				fragptr +=  spc - hlen;
682 			}
683 			inl = (void *) (inl + 1) + spc;
684 			memcpy(((void *)(inl + 1)), fragptr, skb->len - spc);
685 		} else {
686 			skb_copy_from_linear_data(skb, inl + 1, spc);
687 			inl = (void *) (inl + 1) + spc;
688 			skb_copy_from_linear_data_offset(skb, spc, inl + 1,
689 							 hlen - spc);
690 			if (shinfo->nr_frags)
691 				memcpy(((void *)(inl + 1)) + hlen - spc,
692 				       fragptr,
693 				       skb_frag_size(&shinfo->frags[0]));
694 		}
695 
696 		dma_wmb();
697 		inl->byte_count = cpu_to_be32(1 << 31 | (skb->len - spc));
698 	}
699 }
700 
701 u16 mlx4_en_select_queue(struct net_device *dev, struct sk_buff *skb,
702 			 void *accel_priv, select_queue_fallback_t fallback)
703 {
704 	struct mlx4_en_priv *priv = netdev_priv(dev);
705 	u16 rings_p_up = priv->num_tx_rings_p_up;
706 	u8 up = 0;
707 
708 	if (netdev_get_num_tc(dev))
709 		return skb_tx_hash(dev, skb);
710 
711 	if (skb_vlan_tag_present(skb))
712 		up = skb_vlan_tag_get(skb) >> VLAN_PRIO_SHIFT;
713 
714 	return fallback(dev, skb) % rings_p_up + up * rings_p_up;
715 }
716 
717 static void mlx4_bf_copy(void __iomem *dst, const void *src,
718 			 unsigned int bytecnt)
719 {
720 	__iowrite64_copy(dst, src, bytecnt / 8);
721 }
722 
723 void mlx4_en_xmit_doorbell(struct mlx4_en_tx_ring *ring)
724 {
725 	wmb();
726 	/* Since there is no iowrite*_native() that writes the
727 	 * value as is, without byteswapping - using the one
728 	 * the doesn't do byteswapping in the relevant arch
729 	 * endianness.
730 	 */
731 #if defined(__LITTLE_ENDIAN)
732 	iowrite32(
733 #else
734 	iowrite32be(
735 #endif
736 		  ring->doorbell_qpn,
737 		  ring->bf.uar->map + MLX4_SEND_DOORBELL);
738 }
739 
740 static void mlx4_en_tx_write_desc(struct mlx4_en_tx_ring *ring,
741 				  struct mlx4_en_tx_desc *tx_desc,
742 				  union mlx4_wqe_qpn_vlan qpn_vlan,
743 				  int desc_size, int bf_index,
744 				  __be32 op_own, bool bf_ok,
745 				  bool send_doorbell)
746 {
747 	tx_desc->ctrl.qpn_vlan = qpn_vlan;
748 
749 	if (bf_ok) {
750 		op_own |= htonl((bf_index & 0xffff) << 8);
751 		/* Ensure new descriptor hits memory
752 		 * before setting ownership of this descriptor to HW
753 		 */
754 		dma_wmb();
755 		tx_desc->ctrl.owner_opcode = op_own;
756 
757 		wmb();
758 
759 		mlx4_bf_copy(ring->bf.reg + ring->bf.offset, &tx_desc->ctrl,
760 			     desc_size);
761 
762 		wmb();
763 
764 		ring->bf.offset ^= ring->bf.buf_size;
765 	} else {
766 		/* Ensure new descriptor hits memory
767 		 * before setting ownership of this descriptor to HW
768 		 */
769 		dma_wmb();
770 		tx_desc->ctrl.owner_opcode = op_own;
771 		if (send_doorbell)
772 			mlx4_en_xmit_doorbell(ring);
773 		else
774 			ring->xmit_more++;
775 	}
776 }
777 
778 netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
779 {
780 	struct skb_shared_info *shinfo = skb_shinfo(skb);
781 	struct mlx4_en_priv *priv = netdev_priv(dev);
782 	union mlx4_wqe_qpn_vlan	qpn_vlan = {};
783 	struct device *ddev = priv->ddev;
784 	struct mlx4_en_tx_ring *ring;
785 	struct mlx4_en_tx_desc *tx_desc;
786 	struct mlx4_wqe_data_seg *data;
787 	struct mlx4_en_tx_info *tx_info;
788 	int tx_ind = 0;
789 	int nr_txbb;
790 	int desc_size;
791 	int real_size;
792 	u32 index, bf_index;
793 	__be32 op_own;
794 	u16 vlan_proto = 0;
795 	int i_frag;
796 	int lso_header_size;
797 	void *fragptr = NULL;
798 	bool bounce = false;
799 	bool send_doorbell;
800 	bool stop_queue;
801 	bool inline_ok;
802 	u32 ring_cons;
803 	bool bf_ok;
804 
805 	tx_ind = skb_get_queue_mapping(skb);
806 	ring = priv->tx_ring[TX][tx_ind];
807 
808 	if (!priv->port_up)
809 		goto tx_drop;
810 
811 	/* fetch ring->cons far ahead before needing it to avoid stall */
812 	ring_cons = ACCESS_ONCE(ring->cons);
813 
814 	real_size = get_real_size(skb, shinfo, dev, &lso_header_size,
815 				  &inline_ok, &fragptr);
816 	if (unlikely(!real_size))
817 		goto tx_drop_count;
818 
819 	/* Align descriptor to TXBB size */
820 	desc_size = ALIGN(real_size, TXBB_SIZE);
821 	nr_txbb = desc_size / TXBB_SIZE;
822 	if (unlikely(nr_txbb > MAX_DESC_TXBBS)) {
823 		if (netif_msg_tx_err(priv))
824 			en_warn(priv, "Oversized header or SG list\n");
825 		goto tx_drop_count;
826 	}
827 
828 	bf_ok = ring->bf_enabled;
829 	if (skb_vlan_tag_present(skb)) {
830 		qpn_vlan.vlan_tag = cpu_to_be16(skb_vlan_tag_get(skb));
831 		vlan_proto = be16_to_cpu(skb->vlan_proto);
832 		if (vlan_proto == ETH_P_8021AD)
833 			qpn_vlan.ins_vlan = MLX4_WQE_CTRL_INS_SVLAN;
834 		else if (vlan_proto == ETH_P_8021Q)
835 			qpn_vlan.ins_vlan = MLX4_WQE_CTRL_INS_CVLAN;
836 		else
837 			qpn_vlan.ins_vlan = 0;
838 		bf_ok = false;
839 	}
840 
841 	netdev_txq_bql_enqueue_prefetchw(ring->tx_queue);
842 
843 	/* Track current inflight packets for performance analysis */
844 	AVG_PERF_COUNTER(priv->pstats.inflight_avg,
845 			 (u32)(ring->prod - ring_cons - 1));
846 
847 	/* Packet is good - grab an index and transmit it */
848 	index = ring->prod & ring->size_mask;
849 	bf_index = ring->prod;
850 
851 	/* See if we have enough space for whole descriptor TXBB for setting
852 	 * SW ownership on next descriptor; if not, use a bounce buffer. */
853 	if (likely(index + nr_txbb <= ring->size))
854 		tx_desc = ring->buf + index * TXBB_SIZE;
855 	else {
856 		tx_desc = (struct mlx4_en_tx_desc *) ring->bounce_buf;
857 		bounce = true;
858 		bf_ok = false;
859 	}
860 
861 	/* Save skb in tx_info ring */
862 	tx_info = &ring->tx_info[index];
863 	tx_info->skb = skb;
864 	tx_info->nr_txbb = nr_txbb;
865 
866 	data = &tx_desc->data;
867 	if (lso_header_size)
868 		data = ((void *)&tx_desc->lso + ALIGN(lso_header_size + 4,
869 						      DS_SIZE));
870 
871 	/* valid only for none inline segments */
872 	tx_info->data_offset = (void *)data - (void *)tx_desc;
873 
874 	tx_info->inl = inline_ok;
875 
876 	tx_info->linear = (lso_header_size < skb_headlen(skb) &&
877 			   !inline_ok) ? 1 : 0;
878 
879 	tx_info->nr_maps = shinfo->nr_frags + tx_info->linear;
880 	data += tx_info->nr_maps - 1;
881 
882 	if (!tx_info->inl) {
883 		dma_addr_t dma = 0;
884 		u32 byte_count = 0;
885 
886 		/* Map fragments if any */
887 		for (i_frag = shinfo->nr_frags - 1; i_frag >= 0; i_frag--) {
888 			const struct skb_frag_struct *frag;
889 
890 			frag = &shinfo->frags[i_frag];
891 			byte_count = skb_frag_size(frag);
892 			dma = skb_frag_dma_map(ddev, frag,
893 					       0, byte_count,
894 					       DMA_TO_DEVICE);
895 			if (dma_mapping_error(ddev, dma))
896 				goto tx_drop_unmap;
897 
898 			data->addr = cpu_to_be64(dma);
899 			data->lkey = ring->mr_key;
900 			dma_wmb();
901 			data->byte_count = cpu_to_be32(byte_count);
902 			--data;
903 		}
904 
905 		/* Map linear part if needed */
906 		if (tx_info->linear) {
907 			byte_count = skb_headlen(skb) - lso_header_size;
908 
909 			dma = dma_map_single(ddev, skb->data +
910 					     lso_header_size, byte_count,
911 					     PCI_DMA_TODEVICE);
912 			if (dma_mapping_error(ddev, dma))
913 				goto tx_drop_unmap;
914 
915 			data->addr = cpu_to_be64(dma);
916 			data->lkey = ring->mr_key;
917 			dma_wmb();
918 			data->byte_count = cpu_to_be32(byte_count);
919 		}
920 		/* tx completion can avoid cache line miss for common cases */
921 		tx_info->map0_dma = dma;
922 		tx_info->map0_byte_count = byte_count;
923 	}
924 
925 	/*
926 	 * For timestamping add flag to skb_shinfo and
927 	 * set flag for further reference
928 	 */
929 	tx_info->ts_requested = 0;
930 	if (unlikely(ring->hwtstamp_tx_type == HWTSTAMP_TX_ON &&
931 		     shinfo->tx_flags & SKBTX_HW_TSTAMP)) {
932 		shinfo->tx_flags |= SKBTX_IN_PROGRESS;
933 		tx_info->ts_requested = 1;
934 	}
935 
936 	/* Prepare ctrl segement apart opcode+ownership, which depends on
937 	 * whether LSO is used */
938 	tx_desc->ctrl.srcrb_flags = priv->ctrl_flags;
939 	if (likely(skb->ip_summed == CHECKSUM_PARTIAL)) {
940 		if (!skb->encapsulation)
941 			tx_desc->ctrl.srcrb_flags |= cpu_to_be32(MLX4_WQE_CTRL_IP_CSUM |
942 								 MLX4_WQE_CTRL_TCP_UDP_CSUM);
943 		else
944 			tx_desc->ctrl.srcrb_flags |= cpu_to_be32(MLX4_WQE_CTRL_IP_CSUM);
945 		ring->tx_csum++;
946 	}
947 
948 	if (priv->flags & MLX4_EN_FLAG_ENABLE_HW_LOOPBACK) {
949 		struct ethhdr *ethh;
950 
951 		/* Copy dst mac address to wqe. This allows loopback in eSwitch,
952 		 * so that VFs and PF can communicate with each other
953 		 */
954 		ethh = (struct ethhdr *)skb->data;
955 		tx_desc->ctrl.srcrb_flags16[0] = get_unaligned((__be16 *)ethh->h_dest);
956 		tx_desc->ctrl.imm = get_unaligned((__be32 *)(ethh->h_dest + 2));
957 	}
958 
959 	/* Handle LSO (TSO) packets */
960 	if (lso_header_size) {
961 		int i;
962 
963 		/* Mark opcode as LSO */
964 		op_own = cpu_to_be32(MLX4_OPCODE_LSO | (1 << 6)) |
965 			((ring->prod & ring->size) ?
966 				cpu_to_be32(MLX4_EN_BIT_DESC_OWN) : 0);
967 
968 		/* Fill in the LSO prefix */
969 		tx_desc->lso.mss_hdr_size = cpu_to_be32(
970 			shinfo->gso_size << 16 | lso_header_size);
971 
972 		/* Copy headers;
973 		 * note that we already verified that it is linear */
974 		memcpy(tx_desc->lso.header, skb->data, lso_header_size);
975 
976 		ring->tso_packets++;
977 
978 		i = shinfo->gso_segs;
979 		tx_info->nr_bytes = skb->len + (i - 1) * lso_header_size;
980 		ring->packets += i;
981 	} else {
982 		/* Normal (Non LSO) packet */
983 		op_own = cpu_to_be32(MLX4_OPCODE_SEND) |
984 			((ring->prod & ring->size) ?
985 			 cpu_to_be32(MLX4_EN_BIT_DESC_OWN) : 0);
986 		tx_info->nr_bytes = max_t(unsigned int, skb->len, ETH_ZLEN);
987 		ring->packets++;
988 	}
989 	ring->bytes += tx_info->nr_bytes;
990 	netdev_tx_sent_queue(ring->tx_queue, tx_info->nr_bytes);
991 	AVG_PERF_COUNTER(priv->pstats.tx_pktsz_avg, skb->len);
992 
993 	if (tx_info->inl)
994 		build_inline_wqe(tx_desc, skb, shinfo, fragptr);
995 
996 	if (skb->encapsulation) {
997 		union {
998 			struct iphdr *v4;
999 			struct ipv6hdr *v6;
1000 			unsigned char *hdr;
1001 		} ip;
1002 		u8 proto;
1003 
1004 		ip.hdr = skb_inner_network_header(skb);
1005 		proto = (ip.v4->version == 4) ? ip.v4->protocol :
1006 						ip.v6->nexthdr;
1007 
1008 		if (proto == IPPROTO_TCP || proto == IPPROTO_UDP)
1009 			op_own |= cpu_to_be32(MLX4_WQE_CTRL_IIP | MLX4_WQE_CTRL_ILP);
1010 		else
1011 			op_own |= cpu_to_be32(MLX4_WQE_CTRL_IIP);
1012 	}
1013 
1014 	ring->prod += nr_txbb;
1015 
1016 	/* If we used a bounce buffer then copy descriptor back into place */
1017 	if (unlikely(bounce))
1018 		tx_desc = mlx4_en_bounce_to_desc(priv, ring, index, desc_size);
1019 
1020 	skb_tx_timestamp(skb);
1021 
1022 	/* Check available TXBBs And 2K spare for prefetch */
1023 	stop_queue = mlx4_en_is_tx_ring_full(ring);
1024 	if (unlikely(stop_queue)) {
1025 		netif_tx_stop_queue(ring->tx_queue);
1026 		ring->queue_stopped++;
1027 	}
1028 	send_doorbell = !skb->xmit_more || netif_xmit_stopped(ring->tx_queue);
1029 
1030 	real_size = (real_size / 16) & 0x3f;
1031 
1032 	bf_ok &= desc_size <= MAX_BF && send_doorbell;
1033 
1034 	if (bf_ok)
1035 		qpn_vlan.bf_qpn = ring->doorbell_qpn | cpu_to_be32(real_size);
1036 	else
1037 		qpn_vlan.fence_size = real_size;
1038 
1039 	mlx4_en_tx_write_desc(ring, tx_desc, qpn_vlan, desc_size, bf_index,
1040 			      op_own, bf_ok, send_doorbell);
1041 
1042 	if (unlikely(stop_queue)) {
1043 		/* If queue was emptied after the if (stop_queue) , and before
1044 		 * the netif_tx_stop_queue() - need to wake the queue,
1045 		 * or else it will remain stopped forever.
1046 		 * Need a memory barrier to make sure ring->cons was not
1047 		 * updated before queue was stopped.
1048 		 */
1049 		smp_rmb();
1050 
1051 		ring_cons = ACCESS_ONCE(ring->cons);
1052 		if (unlikely(!mlx4_en_is_tx_ring_full(ring))) {
1053 			netif_tx_wake_queue(ring->tx_queue);
1054 			ring->wake_queue++;
1055 		}
1056 	}
1057 	return NETDEV_TX_OK;
1058 
1059 tx_drop_unmap:
1060 	en_err(priv, "DMA mapping error\n");
1061 
1062 	while (++i_frag < shinfo->nr_frags) {
1063 		++data;
1064 		dma_unmap_page(ddev, (dma_addr_t) be64_to_cpu(data->addr),
1065 			       be32_to_cpu(data->byte_count),
1066 			       PCI_DMA_TODEVICE);
1067 	}
1068 
1069 tx_drop_count:
1070 	ring->tx_dropped++;
1071 tx_drop:
1072 	dev_kfree_skb_any(skb);
1073 	return NETDEV_TX_OK;
1074 }
1075 
1076 netdev_tx_t mlx4_en_xmit_frame(struct mlx4_en_rx_ring *rx_ring,
1077 			       struct mlx4_en_rx_alloc *frame,
1078 			       struct net_device *dev, unsigned int length,
1079 			       int tx_ind, int *doorbell_pending)
1080 {
1081 	struct mlx4_en_priv *priv = netdev_priv(dev);
1082 	union mlx4_wqe_qpn_vlan	qpn_vlan = {};
1083 	struct mlx4_en_tx_ring *ring;
1084 	struct mlx4_en_tx_desc *tx_desc;
1085 	struct mlx4_wqe_data_seg *data;
1086 	struct mlx4_en_tx_info *tx_info;
1087 	int index, bf_index;
1088 	bool send_doorbell;
1089 	int nr_txbb = 1;
1090 	bool stop_queue;
1091 	dma_addr_t dma;
1092 	int real_size;
1093 	__be32 op_own;
1094 	u32 ring_cons;
1095 	bool bf_ok;
1096 
1097 	BUILD_BUG_ON_MSG(ALIGN(CTRL_SIZE + DS_SIZE, TXBB_SIZE) != TXBB_SIZE,
1098 			 "mlx4_en_xmit_frame requires minimum size tx desc");
1099 
1100 	ring = priv->tx_ring[TX_XDP][tx_ind];
1101 
1102 	if (!priv->port_up)
1103 		goto tx_drop;
1104 
1105 	if (mlx4_en_is_tx_ring_full(ring))
1106 		goto tx_drop_count;
1107 
1108 	/* fetch ring->cons far ahead before needing it to avoid stall */
1109 	ring_cons = READ_ONCE(ring->cons);
1110 
1111 	index = ring->prod & ring->size_mask;
1112 	tx_info = &ring->tx_info[index];
1113 
1114 	bf_ok = ring->bf_enabled;
1115 
1116 	/* Track current inflight packets for performance analysis */
1117 	AVG_PERF_COUNTER(priv->pstats.inflight_avg,
1118 			 (u32)(ring->prod - ring_cons - 1));
1119 
1120 	bf_index = ring->prod;
1121 	tx_desc = ring->buf + index * TXBB_SIZE;
1122 	data = &tx_desc->data;
1123 
1124 	dma = frame->dma;
1125 
1126 	tx_info->page = frame->page;
1127 	frame->page = NULL;
1128 	tx_info->map0_dma = dma;
1129 	tx_info->map0_byte_count = PAGE_SIZE;
1130 	tx_info->nr_txbb = nr_txbb;
1131 	tx_info->nr_bytes = max_t(unsigned int, length, ETH_ZLEN);
1132 	tx_info->data_offset = (void *)data - (void *)tx_desc;
1133 	tx_info->ts_requested = 0;
1134 	tx_info->nr_maps = 1;
1135 	tx_info->linear = 1;
1136 	tx_info->inl = 0;
1137 
1138 	dma_sync_single_range_for_device(priv->ddev, dma, frame->page_offset,
1139 					 length, PCI_DMA_TODEVICE);
1140 
1141 	data->addr = cpu_to_be64(dma + frame->page_offset);
1142 	data->lkey = ring->mr_key;
1143 	dma_wmb();
1144 	data->byte_count = cpu_to_be32(length);
1145 
1146 	/* tx completion can avoid cache line miss for common cases */
1147 	tx_desc->ctrl.srcrb_flags = priv->ctrl_flags;
1148 
1149 	op_own = cpu_to_be32(MLX4_OPCODE_SEND) |
1150 		((ring->prod & ring->size) ?
1151 		 cpu_to_be32(MLX4_EN_BIT_DESC_OWN) : 0);
1152 
1153 	rx_ring->xdp_tx++;
1154 	AVG_PERF_COUNTER(priv->pstats.tx_pktsz_avg, length);
1155 
1156 	ring->prod += nr_txbb;
1157 
1158 	stop_queue = mlx4_en_is_tx_ring_full(ring);
1159 	send_doorbell = stop_queue ||
1160 				*doorbell_pending > MLX4_EN_DOORBELL_BUDGET;
1161 	bf_ok &= send_doorbell;
1162 
1163 	real_size = ((CTRL_SIZE + nr_txbb * DS_SIZE) / 16) & 0x3f;
1164 
1165 	if (bf_ok)
1166 		qpn_vlan.bf_qpn = ring->doorbell_qpn | cpu_to_be32(real_size);
1167 	else
1168 		qpn_vlan.fence_size = real_size;
1169 
1170 	mlx4_en_tx_write_desc(ring, tx_desc, qpn_vlan, TXBB_SIZE, bf_index,
1171 			      op_own, bf_ok, send_doorbell);
1172 	*doorbell_pending = send_doorbell ? 0 : *doorbell_pending + 1;
1173 
1174 	return NETDEV_TX_OK;
1175 
1176 tx_drop_count:
1177 	rx_ring->xdp_tx_full++;
1178 tx_drop:
1179 	return NETDEV_TX_BUSY;
1180 }
1181