mlx5_en_tx.c revision 341981
1/*-
2 * Copyright (c) 2015-2018 Mellanox Technologies. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS `AS IS' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 *
25 * $FreeBSD: stable/11/sys/dev/mlx5/mlx5_en/mlx5_en_tx.c 341981 2018-12-12 13:12:30Z hselasky $
26 */
27
28#include "en.h"
29#include <machine/atomic.h>
30
31static inline bool
32mlx5e_do_send_cqe(struct mlx5e_sq *sq)
33{
34	sq->cev_counter++;
35	/* interleave the CQEs */
36	if (sq->cev_counter >= sq->cev_factor) {
37		sq->cev_counter = 0;
38		return (1);
39	}
40	return (0);
41}
42
43void
44mlx5e_send_nop(struct mlx5e_sq *sq, u32 ds_cnt)
45{
46	u16 pi = sq->pc & sq->wq.sz_m1;
47	struct mlx5e_tx_wqe *wqe = mlx5_wq_cyc_get_wqe(&sq->wq, pi);
48
49	memset(&wqe->ctrl, 0, sizeof(wqe->ctrl));
50
51	wqe->ctrl.opmod_idx_opcode = cpu_to_be32((sq->pc << 8) | MLX5_OPCODE_NOP);
52	wqe->ctrl.qpn_ds = cpu_to_be32((sq->sqn << 8) | ds_cnt);
53	if (mlx5e_do_send_cqe(sq))
54		wqe->ctrl.fm_ce_se = MLX5_WQE_CTRL_CQ_UPDATE;
55	else
56		wqe->ctrl.fm_ce_se = 0;
57
58	/* Copy data for doorbell */
59	memcpy(sq->doorbell.d32, &wqe->ctrl, sizeof(sq->doorbell.d32));
60
61	sq->mbuf[pi].mbuf = NULL;
62	sq->mbuf[pi].num_bytes = 0;
63	sq->mbuf[pi].num_wqebbs = DIV_ROUND_UP(ds_cnt, MLX5_SEND_WQEBB_NUM_DS);
64	sq->pc += sq->mbuf[pi].num_wqebbs;
65}
66
67#if (__FreeBSD_version >= 1100000)
68static uint32_t mlx5e_hash_value;
69
70static void
71mlx5e_hash_init(void *arg)
72{
73	mlx5e_hash_value = m_ether_tcpip_hash_init();
74}
75
76/* Make kernel call mlx5e_hash_init after the random stack finished initializing */
77SYSINIT(mlx5e_hash_init, SI_SUB_RANDOM, SI_ORDER_ANY, &mlx5e_hash_init, NULL);
78#endif
79
80static struct mlx5e_sq *
81mlx5e_select_queue(struct ifnet *ifp, struct mbuf *mb)
82{
83	struct mlx5e_priv *priv = ifp->if_softc;
84	struct mlx5e_sq *sq;
85	u32 ch;
86	u32 tc;
87
88	/* obtain VLAN information if present */
89	if (mb->m_flags & M_VLANTAG) {
90		tc = (mb->m_pkthdr.ether_vtag >> 13);
91		if (tc >= priv->num_tc)
92			tc = priv->default_vlan_prio;
93	} else {
94		tc = priv->default_vlan_prio;
95	}
96
97	ch = priv->params.num_channels;
98
99	/* check if flowid is set */
100	if (M_HASHTYPE_GET(mb) != M_HASHTYPE_NONE) {
101#ifdef RSS
102		u32 temp;
103
104		if (rss_hash2bucket(mb->m_pkthdr.flowid,
105		    M_HASHTYPE_GET(mb), &temp) == 0)
106			ch = temp % ch;
107		else
108#endif
109			ch = (mb->m_pkthdr.flowid % 128) % ch;
110	} else {
111#if (__FreeBSD_version >= 1100000)
112		ch = m_ether_tcpip_hash(MBUF_HASHFLAG_L3 |
113		    MBUF_HASHFLAG_L4, mb, mlx5e_hash_value) % ch;
114#else
115		/*
116		 * m_ether_tcpip_hash not present in stable, so just
117		 * throw unhashed mbufs on queue 0
118		 */
119		ch = 0;
120#endif
121	}
122
123	/* check if send queue is running */
124	sq = &priv->channel[ch].sq[tc];
125	if (likely(READ_ONCE(sq->running) != 0))
126		return (sq);
127	return (NULL);
128}
129
130static inline u16
131mlx5e_get_l2_header_size(struct mlx5e_sq *sq, struct mbuf *mb)
132{
133	struct ether_vlan_header *eh;
134	uint16_t eth_type;
135	int min_inline;
136
137	eh = mtod(mb, struct ether_vlan_header *);
138	if (unlikely(mb->m_len < ETHER_HDR_LEN)) {
139		goto max_inline;
140	} else if (eh->evl_encap_proto == htons(ETHERTYPE_VLAN)) {
141		if (unlikely(mb->m_len < (ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN)))
142			goto max_inline;
143		eth_type = ntohs(eh->evl_proto);
144		min_inline = ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN;
145	} else {
146		eth_type = ntohs(eh->evl_encap_proto);
147		min_inline = ETHER_HDR_LEN;
148	}
149
150	switch (eth_type) {
151	case ETHERTYPE_IP:
152	case ETHERTYPE_IPV6:
153		/*
154		 * Make sure the TOS(IPv4) or traffic class(IPv6)
155		 * field gets inlined. Else the SQ may stall.
156		 */
157		min_inline += 4;
158		break;
159	default:
160		goto max_inline;
161	}
162
163	/*
164	 * m_copydata() will be used on the remaining header which
165	 * does not need to reside within the first m_len bytes of
166	 * data:
167	 */
168	if (mb->m_pkthdr.len < min_inline)
169		goto max_inline;
170	return (min_inline);
171
172max_inline:
173	return (MIN(mb->m_pkthdr.len, sq->max_inline));
174}
175
176static int
177mlx5e_get_full_header_size(struct mbuf *mb)
178{
179	struct ether_vlan_header *eh;
180	struct tcphdr *th;
181	struct ip *ip;
182	int ip_hlen, tcp_hlen;
183	struct ip6_hdr *ip6;
184	uint16_t eth_type;
185	int eth_hdr_len;
186
187	eh = mtod(mb, struct ether_vlan_header *);
188	if (mb->m_len < ETHER_HDR_LEN)
189		return (0);
190	if (eh->evl_encap_proto == htons(ETHERTYPE_VLAN)) {
191		if (mb->m_len < (ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN))
192			return (0);
193		eth_type = ntohs(eh->evl_proto);
194		eth_hdr_len = ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN;
195	} else {
196		eth_type = ntohs(eh->evl_encap_proto);
197		eth_hdr_len = ETHER_HDR_LEN;
198	}
199	switch (eth_type) {
200	case ETHERTYPE_IP:
201		ip = (struct ip *)(mb->m_data + eth_hdr_len);
202		if (mb->m_len < eth_hdr_len + sizeof(*ip))
203			return (0);
204		switch (ip->ip_p) {
205		case IPPROTO_TCP:
206			ip_hlen = ip->ip_hl << 2;
207			eth_hdr_len += ip_hlen;
208			break;
209		case IPPROTO_UDP:
210			ip_hlen = ip->ip_hl << 2;
211			eth_hdr_len += ip_hlen + 8;
212			goto done;
213		default:
214			return (0);
215		}
216		break;
217	case ETHERTYPE_IPV6:
218		ip6 = (struct ip6_hdr *)(mb->m_data + eth_hdr_len);
219		if (mb->m_len < eth_hdr_len + sizeof(*ip6))
220			return (0);
221		switch (ip6->ip6_nxt) {
222		case IPPROTO_TCP:
223			eth_hdr_len += sizeof(*ip6);
224			break;
225		case IPPROTO_UDP:
226			eth_hdr_len += sizeof(*ip6) + 8;
227			goto done;
228		default:
229			return (0);
230		}
231		break;
232	default:
233		return (0);
234	}
235	if (mb->m_len < eth_hdr_len + sizeof(*th))
236		return (0);
237	th = (struct tcphdr *)(mb->m_data + eth_hdr_len);
238	tcp_hlen = th->th_off << 2;
239	eth_hdr_len += tcp_hlen;
240done:
241	/*
242	 * m_copydata() will be used on the remaining header which
243	 * does not need to reside within the first m_len bytes of
244	 * data:
245	 */
246	if (mb->m_pkthdr.len < eth_hdr_len)
247		return (0);
248	return (eth_hdr_len);
249}
250
251static int
252mlx5e_sq_xmit(struct mlx5e_sq *sq, struct mbuf **mbp)
253{
254	bus_dma_segment_t segs[MLX5E_MAX_TX_MBUF_FRAGS];
255	struct mlx5_wqe_data_seg *dseg;
256	struct mlx5e_tx_wqe *wqe;
257	struct ifnet *ifp;
258	int nsegs;
259	int err;
260	int x;
261	struct mbuf *mb = *mbp;
262	u16 ds_cnt;
263	u16 ihs;
264	u16 pi;
265	u8 opcode;
266
267	/* Return ENOBUFS if the queue is full */
268	if (unlikely(!mlx5e_sq_has_room_for(sq, 2 * MLX5_SEND_WQE_MAX_WQEBBS)))
269		return (ENOBUFS);
270
271	/* Align SQ edge with NOPs to avoid WQE wrap around */
272	pi = ((~sq->pc) & sq->wq.sz_m1);
273	if (pi < (MLX5_SEND_WQE_MAX_WQEBBS - 1)) {
274		/* Send one multi NOP message instead of many */
275		mlx5e_send_nop(sq, (pi + 1) * MLX5_SEND_WQEBB_NUM_DS);
276		pi = ((~sq->pc) & sq->wq.sz_m1);
277		if (pi < (MLX5_SEND_WQE_MAX_WQEBBS - 1))
278			return (ENOMEM);
279	}
280
281	/* Setup local variables */
282	pi = sq->pc & sq->wq.sz_m1;
283	wqe = mlx5_wq_cyc_get_wqe(&sq->wq, pi);
284	ifp = sq->ifp;
285
286	memset(wqe, 0, sizeof(*wqe));
287
288	/* Send a copy of the frame to the BPF listener, if any */
289	if (ifp != NULL && ifp->if_bpf != NULL)
290		ETHER_BPF_MTAP(ifp, mb);
291
292	if (mb->m_pkthdr.csum_flags & (CSUM_IP | CSUM_TSO)) {
293		wqe->eth.cs_flags |= MLX5_ETH_WQE_L3_CSUM;
294	}
295	if (mb->m_pkthdr.csum_flags & (CSUM_TCP | CSUM_UDP | CSUM_UDP_IPV6 | CSUM_TCP_IPV6 | CSUM_TSO)) {
296		wqe->eth.cs_flags |= MLX5_ETH_WQE_L4_CSUM;
297	}
298	if (wqe->eth.cs_flags == 0) {
299		sq->stats.csum_offload_none++;
300	}
301	if (mb->m_pkthdr.csum_flags & CSUM_TSO) {
302		u32 payload_len;
303		u32 mss = mb->m_pkthdr.tso_segsz;
304		u32 num_pkts;
305
306		wqe->eth.mss = cpu_to_be16(mss);
307		opcode = MLX5_OPCODE_LSO;
308		ihs = mlx5e_get_full_header_size(mb);
309		if (unlikely(ihs == 0)) {
310			err = EINVAL;
311			goto tx_drop;
312		}
313		payload_len = mb->m_pkthdr.len - ihs;
314		if (payload_len == 0)
315			num_pkts = 1;
316		else
317			num_pkts = DIV_ROUND_UP(payload_len, mss);
318		sq->mbuf[pi].num_bytes = payload_len + (num_pkts * ihs);
319
320		sq->stats.tso_packets++;
321		sq->stats.tso_bytes += payload_len;
322	} else {
323		opcode = MLX5_OPCODE_SEND;
324
325		switch (sq->min_inline_mode) {
326		case MLX5_INLINE_MODE_IP:
327		case MLX5_INLINE_MODE_TCP_UDP:
328			ihs = mlx5e_get_full_header_size(mb);
329			if (unlikely(ihs == 0))
330				ihs = mlx5e_get_l2_header_size(sq, mb);
331			break;
332		case MLX5_INLINE_MODE_L2:
333			ihs = mlx5e_get_l2_header_size(sq, mb);
334			break;
335		case MLX5_INLINE_MODE_NONE:
336			/* FALLTHROUGH */
337		default:
338			if ((mb->m_flags & M_VLANTAG) != 0 &&
339			    (sq->min_insert_caps & MLX5E_INSERT_VLAN) != 0) {
340				/* inlining VLAN data is not required */
341				wqe->eth.vlan_cmd = htons(0x8000); /* bit 0 CVLAN */
342				wqe->eth.vlan_hdr = htons(mb->m_pkthdr.ether_vtag);
343				ihs = 0;
344			} else if ((mb->m_flags & M_VLANTAG) == 0 &&
345				   (sq->min_insert_caps & MLX5E_INSERT_NON_VLAN) != 0) {
346				/* inlining non-VLAN data is not required */
347				ihs = 0;
348			} else {
349				/* we are forced to inlining L2 header, if any */
350				ihs = mlx5e_get_l2_header_size(sq, mb);
351			}
352			break;
353		}
354		sq->mbuf[pi].num_bytes = max_t (unsigned int,
355		    mb->m_pkthdr.len, ETHER_MIN_LEN - ETHER_CRC_LEN);
356	}
357
358	if (likely(ihs == 0)) {
359		/* nothing to inline */
360	} else if (unlikely(ihs > sq->max_inline)) {
361		/* inline header size is too big */
362		err = EINVAL;
363		goto tx_drop;
364	} else if ((mb->m_flags & M_VLANTAG) != 0) {
365		struct ether_vlan_header *eh = (struct ether_vlan_header *)
366		    wqe->eth.inline_hdr_start;
367
368		/* Range checks */
369		if (unlikely(ihs > (MLX5E_MAX_TX_INLINE - ETHER_VLAN_ENCAP_LEN)))
370			ihs = (MLX5E_MAX_TX_INLINE - ETHER_VLAN_ENCAP_LEN);
371		else if (unlikely(ihs < ETHER_HDR_LEN)) {
372			err = EINVAL;
373			goto tx_drop;
374		}
375		m_copydata(mb, 0, ETHER_HDR_LEN, (caddr_t)eh);
376		m_adj(mb, ETHER_HDR_LEN);
377		/* Insert 4 bytes VLAN tag into data stream */
378		eh->evl_proto = eh->evl_encap_proto;
379		eh->evl_encap_proto = htons(ETHERTYPE_VLAN);
380		eh->evl_tag = htons(mb->m_pkthdr.ether_vtag);
381		/* Copy rest of header data, if any */
382		m_copydata(mb, 0, ihs - ETHER_HDR_LEN, (caddr_t)(eh + 1));
383		m_adj(mb, ihs - ETHER_HDR_LEN);
384		/* Extend header by 4 bytes */
385		ihs += ETHER_VLAN_ENCAP_LEN;
386		wqe->eth.inline_hdr_sz = cpu_to_be16(ihs);
387	} else {
388		m_copydata(mb, 0, ihs, wqe->eth.inline_hdr_start);
389		m_adj(mb, ihs);
390		wqe->eth.inline_hdr_sz = cpu_to_be16(ihs);
391	}
392
393	ds_cnt = sizeof(*wqe) / MLX5_SEND_WQE_DS;
394	if (ihs > sizeof(wqe->eth.inline_hdr_start)) {
395		ds_cnt += DIV_ROUND_UP(ihs - sizeof(wqe->eth.inline_hdr_start),
396		    MLX5_SEND_WQE_DS);
397	}
398	dseg = ((struct mlx5_wqe_data_seg *)&wqe->ctrl) + ds_cnt;
399
400	err = bus_dmamap_load_mbuf_sg(sq->dma_tag, sq->mbuf[pi].dma_map,
401	    mb, segs, &nsegs, BUS_DMA_NOWAIT);
402	if (err == EFBIG) {
403		/* Update statistics */
404		sq->stats.defragged++;
405		/* Too many mbuf fragments */
406		mb = m_defrag(*mbp, M_NOWAIT);
407		if (mb == NULL) {
408			mb = *mbp;
409			goto tx_drop;
410		}
411		/* Try again */
412		err = bus_dmamap_load_mbuf_sg(sq->dma_tag, sq->mbuf[pi].dma_map,
413		    mb, segs, &nsegs, BUS_DMA_NOWAIT);
414	}
415	/* Catch errors */
416	if (err != 0)
417		goto tx_drop;
418
419	/* Make sure all mbuf data, if any, is written to RAM */
420	if (nsegs != 0) {
421		bus_dmamap_sync(sq->dma_tag, sq->mbuf[pi].dma_map,
422		    BUS_DMASYNC_PREWRITE);
423	} else {
424		/* All data was inlined, free the mbuf. */
425		bus_dmamap_unload(sq->dma_tag, sq->mbuf[pi].dma_map);
426		m_freem(mb);
427		mb = NULL;
428	}
429
430	for (x = 0; x != nsegs; x++) {
431		if (segs[x].ds_len == 0)
432			continue;
433		dseg->addr = cpu_to_be64((uint64_t)segs[x].ds_addr);
434		dseg->lkey = sq->mkey_be;
435		dseg->byte_count = cpu_to_be32((uint32_t)segs[x].ds_len);
436		dseg++;
437	}
438
439	ds_cnt = (dseg - ((struct mlx5_wqe_data_seg *)&wqe->ctrl));
440
441	wqe->ctrl.opmod_idx_opcode = cpu_to_be32((sq->pc << 8) | opcode);
442	wqe->ctrl.qpn_ds = cpu_to_be32((sq->sqn << 8) | ds_cnt);
443	if (mlx5e_do_send_cqe(sq))
444		wqe->ctrl.fm_ce_se = MLX5_WQE_CTRL_CQ_UPDATE;
445	else
446		wqe->ctrl.fm_ce_se = 0;
447
448	/* Copy data for doorbell */
449	memcpy(sq->doorbell.d32, &wqe->ctrl, sizeof(sq->doorbell.d32));
450
451	/* Store pointer to mbuf */
452	sq->mbuf[pi].mbuf = mb;
453	sq->mbuf[pi].num_wqebbs = DIV_ROUND_UP(ds_cnt, MLX5_SEND_WQEBB_NUM_DS);
454	sq->pc += sq->mbuf[pi].num_wqebbs;
455
456	/* Count all traffic going out */
457	sq->stats.packets++;
458	sq->stats.bytes += sq->mbuf[pi].num_bytes;
459
460	*mbp = NULL;	/* safety clear */
461	return (0);
462
463tx_drop:
464	sq->stats.dropped++;
465	*mbp = NULL;
466	m_freem(mb);
467	return err;
468}
469
470static void
471mlx5e_poll_tx_cq(struct mlx5e_sq *sq, int budget)
472{
473	u16 sqcc;
474
475	/*
476	 * sq->cc must be updated only after mlx5_cqwq_update_db_record(),
477	 * otherwise a cq overrun may occur
478	 */
479	sqcc = sq->cc;
480
481	while (budget > 0) {
482		struct mlx5_cqe64 *cqe;
483		struct mbuf *mb;
484		u16 x;
485		u16 ci;
486
487		cqe = mlx5e_get_cqe(&sq->cq);
488		if (!cqe)
489			break;
490
491		mlx5_cqwq_pop(&sq->cq.wq);
492
493		/* update budget according to the event factor */
494		budget -= sq->cev_factor;
495
496		for (x = 0; x != sq->cev_factor; x++) {
497			ci = sqcc & sq->wq.sz_m1;
498			mb = sq->mbuf[ci].mbuf;
499			sq->mbuf[ci].mbuf = NULL;	/* Safety clear */
500
501			if (mb == NULL) {
502				if (sq->mbuf[ci].num_bytes == 0) {
503					/* NOP */
504					sq->stats.nop++;
505				}
506			} else {
507				bus_dmamap_sync(sq->dma_tag, sq->mbuf[ci].dma_map,
508				    BUS_DMASYNC_POSTWRITE);
509				bus_dmamap_unload(sq->dma_tag, sq->mbuf[ci].dma_map);
510
511				/* Free transmitted mbuf */
512				m_freem(mb);
513			}
514			sqcc += sq->mbuf[ci].num_wqebbs;
515		}
516	}
517
518	mlx5_cqwq_update_db_record(&sq->cq.wq);
519
520	/* Ensure cq space is freed before enabling more cqes */
521	atomic_thread_fence_rel();
522
523	sq->cc = sqcc;
524}
525
526static int
527mlx5e_xmit_locked(struct ifnet *ifp, struct mlx5e_sq *sq, struct mbuf *mb)
528{
529	int err = 0;
530
531	if (unlikely((ifp->if_drv_flags & IFF_DRV_RUNNING) == 0 ||
532	    READ_ONCE(sq->running) == 0)) {
533		m_freem(mb);
534		return (ENETDOWN);
535	}
536
537	/* Do transmit */
538	if (mlx5e_sq_xmit(sq, &mb) != 0) {
539		/* NOTE: m_freem() is NULL safe */
540		m_freem(mb);
541		err = ENOBUFS;
542	}
543
544	/* Check if we need to write the doorbell */
545	if (likely(sq->doorbell.d64 != 0)) {
546		mlx5e_tx_notify_hw(sq, sq->doorbell.d32, 0);
547		sq->doorbell.d64 = 0;
548	}
549
550	/*
551	 * Check if we need to start the event timer which flushes the
552	 * transmit ring on timeout:
553	 */
554	if (unlikely(sq->cev_next_state == MLX5E_CEV_STATE_INITIAL &&
555	    sq->cev_factor != 1)) {
556		/* start the timer */
557		mlx5e_sq_cev_timeout(sq);
558	} else {
559		/* don't send NOPs yet */
560		sq->cev_next_state = MLX5E_CEV_STATE_HOLD_NOPS;
561	}
562	return (err);
563}
564
565int
566mlx5e_xmit(struct ifnet *ifp, struct mbuf *mb)
567{
568	struct mlx5e_sq *sq;
569	int ret;
570
571	sq = mlx5e_select_queue(ifp, mb);
572	if (unlikely(sq == NULL)) {
573		/* Invalid send queue */
574		m_freem(mb);
575		return (ENXIO);
576	}
577
578	mtx_lock(&sq->lock);
579	ret = mlx5e_xmit_locked(ifp, sq, mb);
580	mtx_unlock(&sq->lock);
581
582	return (ret);
583}
584
585void
586mlx5e_tx_cq_comp(struct mlx5_core_cq *mcq)
587{
588	struct mlx5e_sq *sq = container_of(mcq, struct mlx5e_sq, cq.mcq);
589
590	mtx_lock(&sq->comp_lock);
591	mlx5e_poll_tx_cq(sq, MLX5E_BUDGET_MAX);
592	mlx5e_cq_arm(&sq->cq, MLX5_GET_DOORBELL_LOCK(&sq->priv->doorbell_lock));
593	mtx_unlock(&sq->comp_lock);
594}
595