xref: /linux/fs/smb/server/transport_rdma.c (revision cc2f08129925b437bf28f7f7822f20dac083a87c)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *   Copyright (C) 2017, Microsoft Corporation.
4  *   Copyright (C) 2018, LG Electronics.
5  *
6  *   Author(s): Long Li <longli@microsoft.com>,
7  *		Hyunchul Lee <hyc.lee@gmail.com>
8  */
9 
10 #define SUBMOD_NAME	"smb_direct"
11 
12 #include <linux/kthread.h>
13 #include <linux/list.h>
14 #include <linux/mempool.h>
15 #include <linux/highmem.h>
16 #include <linux/scatterlist.h>
17 #include <linux/string_choices.h>
18 #include <rdma/ib_verbs.h>
19 #include <rdma/rdma_cm.h>
20 #include <rdma/rw.h>
21 
22 #include "glob.h"
23 #include "connection.h"
24 #include "smb_common.h"
25 #include "../common/smb2status.h"
26 #include "transport_rdma.h"
27 
28 #define SMB_DIRECT_PORT_IWARP		5445
29 #define SMB_DIRECT_PORT_INFINIBAND	445
30 
31 #define SMB_DIRECT_VERSION_LE		cpu_to_le16(0x0100)
32 
33 /* SMB_DIRECT negotiation timeout in seconds */
34 #define SMB_DIRECT_NEGOTIATE_TIMEOUT		120
35 
36 #define SMB_DIRECT_MAX_SEND_SGES		6
37 #define SMB_DIRECT_MAX_RECV_SGES		1
38 
39 /*
40  * Default maximum number of RDMA read/write outstanding on this connection
41  * This value is possibly decreased during QP creation on hardware limit
42  */
43 #define SMB_DIRECT_CM_INITIATOR_DEPTH		8
44 
45 /* Maximum number of retries on data transfer operations */
46 #define SMB_DIRECT_CM_RETRY			6
47 /* No need to retry on Receiver Not Ready since SMB_DIRECT manages credits */
48 #define SMB_DIRECT_CM_RNR_RETRY		0
49 
50 /*
51  * User configurable initial values per SMB_DIRECT transport connection
52  * as defined in [MS-SMBD] 3.1.1.1
53  * Those may change after a SMB_DIRECT negotiation
54  */
55 
56 /* Set 445 port to SMB Direct port by default */
57 static int smb_direct_port = SMB_DIRECT_PORT_INFINIBAND;
58 
59 /* The local peer's maximum number of credits to grant to the peer */
60 static int smb_direct_receive_credit_max = 255;
61 
62 /* The remote peer's credit request of local peer */
63 static int smb_direct_send_credit_target = 255;
64 
65 /* The maximum single message size can be sent to remote peer */
66 static int smb_direct_max_send_size = 1364;
67 
68 /*  The maximum fragmented upper-layer payload receive size supported */
69 static int smb_direct_max_fragmented_recv_size = 1024 * 1024;
70 
71 /*  The maximum single-message size which can be received */
72 static int smb_direct_max_receive_size = 1364;
73 
74 static int smb_direct_max_read_write_size = SMBD_DEFAULT_IOSIZE;
75 
76 static LIST_HEAD(smb_direct_device_list);
77 static DEFINE_RWLOCK(smb_direct_device_lock);
78 
79 struct smb_direct_device {
80 	struct ib_device	*ib_dev;
81 	struct list_head	list;
82 };
83 
84 static struct smb_direct_listener {
85 	struct rdma_cm_id	*cm_id;
86 } smb_direct_listener;
87 
88 static struct workqueue_struct *smb_direct_wq;
89 
90 enum smb_direct_status {
91 	SMB_DIRECT_CS_NEW = 0,
92 	SMB_DIRECT_CS_CONNECTED,
93 	SMB_DIRECT_CS_DISCONNECTING,
94 	SMB_DIRECT_CS_DISCONNECTED,
95 };
96 
97 struct smb_direct_transport {
98 	struct ksmbd_transport	transport;
99 
100 	enum smb_direct_status	status;
101 	bool			full_packet_received;
102 	wait_queue_head_t	wait_status;
103 
104 	struct rdma_cm_id	*cm_id;
105 	struct ib_cq		*send_cq;
106 	struct ib_cq		*recv_cq;
107 	struct ib_pd		*pd;
108 	struct ib_qp		*qp;
109 
110 	int			max_send_size;
111 	int			max_recv_size;
112 	int			max_fragmented_send_size;
113 	int			max_fragmented_recv_size;
114 	int			max_rdma_rw_size;
115 
116 	spinlock_t		reassembly_queue_lock;
117 	struct list_head	reassembly_queue;
118 	int			reassembly_data_length;
119 	int			reassembly_queue_length;
120 	int			first_entry_offset;
121 	wait_queue_head_t	wait_reassembly_queue;
122 
123 	spinlock_t		receive_credit_lock;
124 	int			recv_credits;
125 	int			count_avail_recvmsg;
126 	int			recv_credit_max;
127 	int			recv_credit_target;
128 
129 	spinlock_t		recvmsg_queue_lock;
130 	struct list_head	recvmsg_queue;
131 
132 	int			send_credit_target;
133 	atomic_t		send_credits;
134 	spinlock_t		lock_new_recv_credits;
135 	int			new_recv_credits;
136 	int			max_rw_credits;
137 	int			pages_per_rw_credit;
138 	atomic_t		rw_credits;
139 
140 	wait_queue_head_t	wait_send_credits;
141 	wait_queue_head_t	wait_rw_credits;
142 
143 	mempool_t		*sendmsg_mempool;
144 	struct kmem_cache	*sendmsg_cache;
145 	mempool_t		*recvmsg_mempool;
146 	struct kmem_cache	*recvmsg_cache;
147 
148 	wait_queue_head_t	wait_send_pending;
149 	atomic_t		send_pending;
150 
151 	struct work_struct	post_recv_credits_work;
152 	struct work_struct	send_immediate_work;
153 	struct work_struct	disconnect_work;
154 
155 	bool			negotiation_requested;
156 };
157 
158 #define KSMBD_TRANS(t) ((struct ksmbd_transport *)&((t)->transport))
159 #define SMBD_TRANS(t)	((struct smb_direct_transport *)container_of(t, \
160 				struct smb_direct_transport, transport))
161 enum {
162 	SMB_DIRECT_MSG_NEGOTIATE_REQ = 0,
163 	SMB_DIRECT_MSG_DATA_TRANSFER
164 };
165 
166 static const struct ksmbd_transport_ops ksmbd_smb_direct_transport_ops;
167 
168 struct smb_direct_send_ctx {
169 	struct list_head	msg_list;
170 	int			wr_cnt;
171 	bool			need_invalidate_rkey;
172 	unsigned int		remote_key;
173 };
174 
175 struct smb_direct_sendmsg {
176 	struct smb_direct_transport	*transport;
177 	struct ib_send_wr	wr;
178 	struct list_head	list;
179 	int			num_sge;
180 	struct ib_sge		sge[SMB_DIRECT_MAX_SEND_SGES];
181 	struct ib_cqe		cqe;
182 	u8			packet[];
183 };
184 
185 struct smb_direct_recvmsg {
186 	struct smb_direct_transport	*transport;
187 	struct list_head	list;
188 	int			type;
189 	struct ib_sge		sge;
190 	struct ib_cqe		cqe;
191 	bool			first_segment;
192 	u8			packet[];
193 };
194 
195 struct smb_direct_rdma_rw_msg {
196 	struct smb_direct_transport	*t;
197 	struct ib_cqe		cqe;
198 	int			status;
199 	struct completion	*completion;
200 	struct list_head	list;
201 	struct rdma_rw_ctx	rw_ctx;
202 	struct sg_table		sgt;
203 	struct scatterlist	sg_list[];
204 };
205 
206 void init_smbd_max_io_size(unsigned int sz)
207 {
208 	sz = clamp_val(sz, SMBD_MIN_IOSIZE, SMBD_MAX_IOSIZE);
209 	smb_direct_max_read_write_size = sz;
210 }
211 
212 unsigned int get_smbd_max_read_write_size(void)
213 {
214 	return smb_direct_max_read_write_size;
215 }
216 
217 static inline int get_buf_page_count(void *buf, int size)
218 {
219 	return DIV_ROUND_UP((uintptr_t)buf + size, PAGE_SIZE) -
220 		(uintptr_t)buf / PAGE_SIZE;
221 }
222 
223 static void smb_direct_destroy_pools(struct smb_direct_transport *transport);
224 static void smb_direct_post_recv_credits(struct work_struct *work);
225 static int smb_direct_post_send_data(struct smb_direct_transport *t,
226 				     struct smb_direct_send_ctx *send_ctx,
227 				     struct kvec *iov, int niov,
228 				     int remaining_data_length);
229 
230 static inline struct smb_direct_transport *
231 smb_trans_direct_transfort(struct ksmbd_transport *t)
232 {
233 	return container_of(t, struct smb_direct_transport, transport);
234 }
235 
236 static inline void
237 *smb_direct_recvmsg_payload(struct smb_direct_recvmsg *recvmsg)
238 {
239 	return (void *)recvmsg->packet;
240 }
241 
242 static inline bool is_receive_credit_post_required(int receive_credits,
243 						   int avail_recvmsg_count)
244 {
245 	return receive_credits <= (smb_direct_receive_credit_max >> 3) &&
246 		avail_recvmsg_count >= (receive_credits >> 2);
247 }
248 
249 static struct
250 smb_direct_recvmsg *get_free_recvmsg(struct smb_direct_transport *t)
251 {
252 	struct smb_direct_recvmsg *recvmsg = NULL;
253 
254 	spin_lock(&t->recvmsg_queue_lock);
255 	if (!list_empty(&t->recvmsg_queue)) {
256 		recvmsg = list_first_entry(&t->recvmsg_queue,
257 					   struct smb_direct_recvmsg,
258 					   list);
259 		list_del(&recvmsg->list);
260 	}
261 	spin_unlock(&t->recvmsg_queue_lock);
262 	return recvmsg;
263 }
264 
265 static void put_recvmsg(struct smb_direct_transport *t,
266 			struct smb_direct_recvmsg *recvmsg)
267 {
268 	if (likely(recvmsg->sge.length != 0)) {
269 		ib_dma_unmap_single(t->cm_id->device,
270 				    recvmsg->sge.addr,
271 				    recvmsg->sge.length,
272 				    DMA_FROM_DEVICE);
273 		recvmsg->sge.length = 0;
274 	}
275 
276 	spin_lock(&t->recvmsg_queue_lock);
277 	list_add(&recvmsg->list, &t->recvmsg_queue);
278 	spin_unlock(&t->recvmsg_queue_lock);
279 }
280 
281 static void enqueue_reassembly(struct smb_direct_transport *t,
282 			       struct smb_direct_recvmsg *recvmsg,
283 			       int data_length)
284 {
285 	spin_lock(&t->reassembly_queue_lock);
286 	list_add_tail(&recvmsg->list, &t->reassembly_queue);
287 	t->reassembly_queue_length++;
288 	/*
289 	 * Make sure reassembly_data_length is updated after list and
290 	 * reassembly_queue_length are updated. On the dequeue side
291 	 * reassembly_data_length is checked without a lock to determine
292 	 * if reassembly_queue_length and list is up to date
293 	 */
294 	virt_wmb();
295 	t->reassembly_data_length += data_length;
296 	spin_unlock(&t->reassembly_queue_lock);
297 }
298 
299 static struct smb_direct_recvmsg *get_first_reassembly(struct smb_direct_transport *t)
300 {
301 	if (!list_empty(&t->reassembly_queue))
302 		return list_first_entry(&t->reassembly_queue,
303 				struct smb_direct_recvmsg, list);
304 	else
305 		return NULL;
306 }
307 
308 static void smb_direct_disconnect_rdma_work(struct work_struct *work)
309 {
310 	struct smb_direct_transport *t =
311 		container_of(work, struct smb_direct_transport,
312 			     disconnect_work);
313 
314 	if (t->status == SMB_DIRECT_CS_CONNECTED) {
315 		t->status = SMB_DIRECT_CS_DISCONNECTING;
316 		rdma_disconnect(t->cm_id);
317 	}
318 }
319 
320 static void
321 smb_direct_disconnect_rdma_connection(struct smb_direct_transport *t)
322 {
323 	if (t->status == SMB_DIRECT_CS_CONNECTED)
324 		queue_work(smb_direct_wq, &t->disconnect_work);
325 }
326 
327 static void smb_direct_send_immediate_work(struct work_struct *work)
328 {
329 	struct smb_direct_transport *t = container_of(work,
330 			struct smb_direct_transport, send_immediate_work);
331 
332 	if (t->status != SMB_DIRECT_CS_CONNECTED)
333 		return;
334 
335 	smb_direct_post_send_data(t, NULL, NULL, 0, 0);
336 }
337 
338 static struct smb_direct_transport *alloc_transport(struct rdma_cm_id *cm_id)
339 {
340 	struct smb_direct_transport *t;
341 	struct ksmbd_conn *conn;
342 
343 	t = kzalloc(sizeof(*t), KSMBD_DEFAULT_GFP);
344 	if (!t)
345 		return NULL;
346 
347 	t->cm_id = cm_id;
348 	cm_id->context = t;
349 
350 	t->status = SMB_DIRECT_CS_NEW;
351 	init_waitqueue_head(&t->wait_status);
352 
353 	spin_lock_init(&t->reassembly_queue_lock);
354 	INIT_LIST_HEAD(&t->reassembly_queue);
355 	t->reassembly_data_length = 0;
356 	t->reassembly_queue_length = 0;
357 	init_waitqueue_head(&t->wait_reassembly_queue);
358 	init_waitqueue_head(&t->wait_send_credits);
359 	init_waitqueue_head(&t->wait_rw_credits);
360 
361 	spin_lock_init(&t->receive_credit_lock);
362 	spin_lock_init(&t->recvmsg_queue_lock);
363 	INIT_LIST_HEAD(&t->recvmsg_queue);
364 
365 	init_waitqueue_head(&t->wait_send_pending);
366 	atomic_set(&t->send_pending, 0);
367 
368 	spin_lock_init(&t->lock_new_recv_credits);
369 
370 	INIT_WORK(&t->post_recv_credits_work,
371 		  smb_direct_post_recv_credits);
372 	INIT_WORK(&t->send_immediate_work, smb_direct_send_immediate_work);
373 	INIT_WORK(&t->disconnect_work, smb_direct_disconnect_rdma_work);
374 
375 	conn = ksmbd_conn_alloc();
376 	if (!conn)
377 		goto err;
378 	conn->transport = KSMBD_TRANS(t);
379 	KSMBD_TRANS(t)->conn = conn;
380 	KSMBD_TRANS(t)->ops = &ksmbd_smb_direct_transport_ops;
381 	return t;
382 err:
383 	kfree(t);
384 	return NULL;
385 }
386 
387 static void smb_direct_free_transport(struct ksmbd_transport *kt)
388 {
389 	kfree(SMBD_TRANS(kt));
390 }
391 
392 static void free_transport(struct smb_direct_transport *t)
393 {
394 	struct smb_direct_recvmsg *recvmsg;
395 
396 	wake_up_interruptible(&t->wait_send_credits);
397 
398 	ksmbd_debug(RDMA, "wait for all send posted to IB to finish\n");
399 	wait_event(t->wait_send_pending,
400 		   atomic_read(&t->send_pending) == 0);
401 
402 	disable_work_sync(&t->disconnect_work);
403 	disable_work_sync(&t->post_recv_credits_work);
404 	disable_work_sync(&t->send_immediate_work);
405 
406 	if (t->qp) {
407 		ib_drain_qp(t->qp);
408 		ib_mr_pool_destroy(t->qp, &t->qp->rdma_mrs);
409 		t->qp = NULL;
410 		rdma_destroy_qp(t->cm_id);
411 	}
412 
413 	ksmbd_debug(RDMA, "drain the reassembly queue\n");
414 	do {
415 		spin_lock(&t->reassembly_queue_lock);
416 		recvmsg = get_first_reassembly(t);
417 		if (recvmsg) {
418 			list_del(&recvmsg->list);
419 			spin_unlock(&t->reassembly_queue_lock);
420 			put_recvmsg(t, recvmsg);
421 		} else {
422 			spin_unlock(&t->reassembly_queue_lock);
423 		}
424 	} while (recvmsg);
425 	t->reassembly_data_length = 0;
426 
427 	if (t->send_cq)
428 		ib_free_cq(t->send_cq);
429 	if (t->recv_cq)
430 		ib_free_cq(t->recv_cq);
431 	if (t->pd)
432 		ib_dealloc_pd(t->pd);
433 	if (t->cm_id)
434 		rdma_destroy_id(t->cm_id);
435 
436 	smb_direct_destroy_pools(t);
437 	ksmbd_conn_free(KSMBD_TRANS(t)->conn);
438 }
439 
440 static struct smb_direct_sendmsg
441 *smb_direct_alloc_sendmsg(struct smb_direct_transport *t)
442 {
443 	struct smb_direct_sendmsg *msg;
444 
445 	msg = mempool_alloc(t->sendmsg_mempool, KSMBD_DEFAULT_GFP);
446 	if (!msg)
447 		return ERR_PTR(-ENOMEM);
448 	msg->transport = t;
449 	INIT_LIST_HEAD(&msg->list);
450 	msg->num_sge = 0;
451 	return msg;
452 }
453 
454 static void smb_direct_free_sendmsg(struct smb_direct_transport *t,
455 				    struct smb_direct_sendmsg *msg)
456 {
457 	int i;
458 
459 	if (msg->num_sge > 0) {
460 		ib_dma_unmap_single(t->cm_id->device,
461 				    msg->sge[0].addr, msg->sge[0].length,
462 				    DMA_TO_DEVICE);
463 		for (i = 1; i < msg->num_sge; i++)
464 			ib_dma_unmap_page(t->cm_id->device,
465 					  msg->sge[i].addr, msg->sge[i].length,
466 					  DMA_TO_DEVICE);
467 	}
468 	mempool_free(msg, t->sendmsg_mempool);
469 }
470 
471 static int smb_direct_check_recvmsg(struct smb_direct_recvmsg *recvmsg)
472 {
473 	switch (recvmsg->type) {
474 	case SMB_DIRECT_MSG_DATA_TRANSFER: {
475 		struct smb_direct_data_transfer *req =
476 			(struct smb_direct_data_transfer *)recvmsg->packet;
477 		struct smb2_hdr *hdr = (struct smb2_hdr *)(recvmsg->packet
478 				+ le32_to_cpu(req->data_offset));
479 		ksmbd_debug(RDMA,
480 			    "CreditGranted: %u, CreditRequested: %u, DataLength: %u, RemainingDataLength: %u, SMB: %x, Command: %u\n",
481 			    le16_to_cpu(req->credits_granted),
482 			    le16_to_cpu(req->credits_requested),
483 			    req->data_length, req->remaining_data_length,
484 			    hdr->ProtocolId, hdr->Command);
485 		break;
486 	}
487 	case SMB_DIRECT_MSG_NEGOTIATE_REQ: {
488 		struct smb_direct_negotiate_req *req =
489 			(struct smb_direct_negotiate_req *)recvmsg->packet;
490 		ksmbd_debug(RDMA,
491 			    "MinVersion: %u, MaxVersion: %u, CreditRequested: %u, MaxSendSize: %u, MaxRecvSize: %u, MaxFragmentedSize: %u\n",
492 			    le16_to_cpu(req->min_version),
493 			    le16_to_cpu(req->max_version),
494 			    le16_to_cpu(req->credits_requested),
495 			    le32_to_cpu(req->preferred_send_size),
496 			    le32_to_cpu(req->max_receive_size),
497 			    le32_to_cpu(req->max_fragmented_size));
498 		if (le16_to_cpu(req->min_version) > 0x0100 ||
499 		    le16_to_cpu(req->max_version) < 0x0100)
500 			return -EOPNOTSUPP;
501 		if (le16_to_cpu(req->credits_requested) <= 0 ||
502 		    le32_to_cpu(req->max_receive_size) <= 128 ||
503 		    le32_to_cpu(req->max_fragmented_size) <=
504 					128 * 1024)
505 			return -ECONNABORTED;
506 
507 		break;
508 	}
509 	default:
510 		return -EINVAL;
511 	}
512 	return 0;
513 }
514 
515 static void recv_done(struct ib_cq *cq, struct ib_wc *wc)
516 {
517 	struct smb_direct_recvmsg *recvmsg;
518 	struct smb_direct_transport *t;
519 
520 	recvmsg = container_of(wc->wr_cqe, struct smb_direct_recvmsg, cqe);
521 	t = recvmsg->transport;
522 
523 	if (wc->status != IB_WC_SUCCESS || wc->opcode != IB_WC_RECV) {
524 		put_recvmsg(t, recvmsg);
525 		if (wc->status != IB_WC_WR_FLUSH_ERR) {
526 			pr_err("Recv error. status='%s (%d)' opcode=%d\n",
527 			       ib_wc_status_msg(wc->status), wc->status,
528 			       wc->opcode);
529 			smb_direct_disconnect_rdma_connection(t);
530 		}
531 		return;
532 	}
533 
534 	ksmbd_debug(RDMA, "Recv completed. status='%s (%d)', opcode=%d\n",
535 		    ib_wc_status_msg(wc->status), wc->status,
536 		    wc->opcode);
537 
538 	ib_dma_sync_single_for_cpu(wc->qp->device, recvmsg->sge.addr,
539 				   recvmsg->sge.length, DMA_FROM_DEVICE);
540 
541 	switch (recvmsg->type) {
542 	case SMB_DIRECT_MSG_NEGOTIATE_REQ:
543 		if (wc->byte_len < sizeof(struct smb_direct_negotiate_req)) {
544 			put_recvmsg(t, recvmsg);
545 			smb_direct_disconnect_rdma_connection(t);
546 			return;
547 		}
548 		t->negotiation_requested = true;
549 		t->full_packet_received = true;
550 		t->status = SMB_DIRECT_CS_CONNECTED;
551 		enqueue_reassembly(t, recvmsg, 0);
552 		wake_up_interruptible(&t->wait_status);
553 		return;
554 	case SMB_DIRECT_MSG_DATA_TRANSFER: {
555 		struct smb_direct_data_transfer *data_transfer =
556 			(struct smb_direct_data_transfer *)recvmsg->packet;
557 		u32 remaining_data_length, data_offset, data_length;
558 		int avail_recvmsg_count, receive_credits;
559 
560 		if (wc->byte_len <
561 		    offsetof(struct smb_direct_data_transfer, padding)) {
562 			put_recvmsg(t, recvmsg);
563 			smb_direct_disconnect_rdma_connection(t);
564 			return;
565 		}
566 
567 		remaining_data_length = le32_to_cpu(data_transfer->remaining_data_length);
568 		data_length = le32_to_cpu(data_transfer->data_length);
569 		data_offset = le32_to_cpu(data_transfer->data_offset);
570 		if (wc->byte_len < data_offset ||
571 		    wc->byte_len < (u64)data_offset + data_length) {
572 			put_recvmsg(t, recvmsg);
573 			smb_direct_disconnect_rdma_connection(t);
574 			return;
575 		}
576 		if (remaining_data_length > t->max_fragmented_recv_size ||
577 		    data_length > t->max_fragmented_recv_size ||
578 		    (u64)remaining_data_length + (u64)data_length >
579 		    (u64)t->max_fragmented_recv_size) {
580 			put_recvmsg(t, recvmsg);
581 			smb_direct_disconnect_rdma_connection(t);
582 			return;
583 		}
584 
585 		if (data_length) {
586 			if (t->full_packet_received)
587 				recvmsg->first_segment = true;
588 
589 			if (le32_to_cpu(data_transfer->remaining_data_length))
590 				t->full_packet_received = false;
591 			else
592 				t->full_packet_received = true;
593 
594 			spin_lock(&t->receive_credit_lock);
595 			receive_credits = --(t->recv_credits);
596 			avail_recvmsg_count = t->count_avail_recvmsg;
597 			spin_unlock(&t->receive_credit_lock);
598 		} else {
599 			spin_lock(&t->receive_credit_lock);
600 			receive_credits = --(t->recv_credits);
601 			avail_recvmsg_count = ++(t->count_avail_recvmsg);
602 			spin_unlock(&t->receive_credit_lock);
603 		}
604 
605 		t->recv_credit_target =
606 				le16_to_cpu(data_transfer->credits_requested);
607 		atomic_add(le16_to_cpu(data_transfer->credits_granted),
608 			   &t->send_credits);
609 
610 		if (le16_to_cpu(data_transfer->flags) &
611 		    SMB_DIRECT_RESPONSE_REQUESTED)
612 			queue_work(smb_direct_wq, &t->send_immediate_work);
613 
614 		if (atomic_read(&t->send_credits) > 0)
615 			wake_up_interruptible(&t->wait_send_credits);
616 
617 		if (is_receive_credit_post_required(receive_credits, avail_recvmsg_count))
618 			queue_work(smb_direct_wq, &t->post_recv_credits_work);
619 
620 		if (data_length) {
621 			enqueue_reassembly(t, recvmsg, (int)data_length);
622 			wake_up_interruptible(&t->wait_reassembly_queue);
623 		} else
624 			put_recvmsg(t, recvmsg);
625 
626 		return;
627 	}
628 	}
629 
630 	/*
631 	 * This is an internal error!
632 	 */
633 	WARN_ON_ONCE(recvmsg->type != SMB_DIRECT_MSG_DATA_TRANSFER);
634 	put_recvmsg(t, recvmsg);
635 	smb_direct_disconnect_rdma_connection(t);
636 }
637 
638 static int smb_direct_post_recv(struct smb_direct_transport *t,
639 				struct smb_direct_recvmsg *recvmsg)
640 {
641 	struct ib_recv_wr wr;
642 	int ret;
643 
644 	recvmsg->sge.addr = ib_dma_map_single(t->cm_id->device,
645 					      recvmsg->packet, t->max_recv_size,
646 					      DMA_FROM_DEVICE);
647 	ret = ib_dma_mapping_error(t->cm_id->device, recvmsg->sge.addr);
648 	if (ret)
649 		return ret;
650 	recvmsg->sge.length = t->max_recv_size;
651 	recvmsg->sge.lkey = t->pd->local_dma_lkey;
652 	recvmsg->cqe.done = recv_done;
653 
654 	wr.wr_cqe = &recvmsg->cqe;
655 	wr.next = NULL;
656 	wr.sg_list = &recvmsg->sge;
657 	wr.num_sge = 1;
658 
659 	ret = ib_post_recv(t->qp, &wr, NULL);
660 	if (ret) {
661 		pr_err("Can't post recv: %d\n", ret);
662 		ib_dma_unmap_single(t->cm_id->device,
663 				    recvmsg->sge.addr, recvmsg->sge.length,
664 				    DMA_FROM_DEVICE);
665 		recvmsg->sge.length = 0;
666 		smb_direct_disconnect_rdma_connection(t);
667 		return ret;
668 	}
669 	return ret;
670 }
671 
672 static int smb_direct_read(struct ksmbd_transport *t, char *buf,
673 			   unsigned int size, int unused)
674 {
675 	struct smb_direct_recvmsg *recvmsg;
676 	struct smb_direct_data_transfer *data_transfer;
677 	int to_copy, to_read, data_read, offset;
678 	u32 data_length, remaining_data_length, data_offset;
679 	int rc;
680 	struct smb_direct_transport *st = smb_trans_direct_transfort(t);
681 
682 again:
683 	if (st->status != SMB_DIRECT_CS_CONNECTED) {
684 		pr_err("disconnected\n");
685 		return -ENOTCONN;
686 	}
687 
688 	/*
689 	 * No need to hold the reassembly queue lock all the time as we are
690 	 * the only one reading from the front of the queue. The transport
691 	 * may add more entries to the back of the queue at the same time
692 	 */
693 	if (st->reassembly_data_length >= size) {
694 		int queue_length;
695 		int queue_removed = 0;
696 
697 		/*
698 		 * Need to make sure reassembly_data_length is read before
699 		 * reading reassembly_queue_length and calling
700 		 * get_first_reassembly. This call is lock free
701 		 * as we never read at the end of the queue which are being
702 		 * updated in SOFTIRQ as more data is received
703 		 */
704 		virt_rmb();
705 		queue_length = st->reassembly_queue_length;
706 		data_read = 0;
707 		to_read = size;
708 		offset = st->first_entry_offset;
709 		while (data_read < size) {
710 			recvmsg = get_first_reassembly(st);
711 			data_transfer = smb_direct_recvmsg_payload(recvmsg);
712 			data_length = le32_to_cpu(data_transfer->data_length);
713 			remaining_data_length =
714 				le32_to_cpu(data_transfer->remaining_data_length);
715 			data_offset = le32_to_cpu(data_transfer->data_offset);
716 
717 			/*
718 			 * The upper layer expects RFC1002 length at the
719 			 * beginning of the payload. Return it to indicate
720 			 * the total length of the packet. This minimize the
721 			 * change to upper layer packet processing logic. This
722 			 * will be eventually remove when an intermediate
723 			 * transport layer is added
724 			 */
725 			if (recvmsg->first_segment && size == 4) {
726 				unsigned int rfc1002_len =
727 					data_length + remaining_data_length;
728 				*((__be32 *)buf) = cpu_to_be32(rfc1002_len);
729 				data_read = 4;
730 				recvmsg->first_segment = false;
731 				ksmbd_debug(RDMA,
732 					    "returning rfc1002 length %d\n",
733 					    rfc1002_len);
734 				goto read_rfc1002_done;
735 			}
736 
737 			to_copy = min_t(int, data_length - offset, to_read);
738 			memcpy(buf + data_read, (char *)data_transfer + data_offset + offset,
739 			       to_copy);
740 
741 			/* move on to the next buffer? */
742 			if (to_copy == data_length - offset) {
743 				queue_length--;
744 				/*
745 				 * No need to lock if we are not at the
746 				 * end of the queue
747 				 */
748 				if (queue_length) {
749 					list_del(&recvmsg->list);
750 				} else {
751 					spin_lock_irq(&st->reassembly_queue_lock);
752 					list_del(&recvmsg->list);
753 					spin_unlock_irq(&st->reassembly_queue_lock);
754 				}
755 				queue_removed++;
756 				put_recvmsg(st, recvmsg);
757 				offset = 0;
758 			} else {
759 				offset += to_copy;
760 			}
761 
762 			to_read -= to_copy;
763 			data_read += to_copy;
764 		}
765 
766 		spin_lock_irq(&st->reassembly_queue_lock);
767 		st->reassembly_data_length -= data_read;
768 		st->reassembly_queue_length -= queue_removed;
769 		spin_unlock_irq(&st->reassembly_queue_lock);
770 
771 		spin_lock(&st->receive_credit_lock);
772 		st->count_avail_recvmsg += queue_removed;
773 		if (is_receive_credit_post_required(st->recv_credits, st->count_avail_recvmsg)) {
774 			spin_unlock(&st->receive_credit_lock);
775 			queue_work(smb_direct_wq, &st->post_recv_credits_work);
776 		} else {
777 			spin_unlock(&st->receive_credit_lock);
778 		}
779 
780 		st->first_entry_offset = offset;
781 		ksmbd_debug(RDMA,
782 			    "returning to thread data_read=%d reassembly_data_length=%d first_entry_offset=%d\n",
783 			    data_read, st->reassembly_data_length,
784 			    st->first_entry_offset);
785 read_rfc1002_done:
786 		return data_read;
787 	}
788 
789 	ksmbd_debug(RDMA, "wait_event on more data\n");
790 	rc = wait_event_interruptible(st->wait_reassembly_queue,
791 				      st->reassembly_data_length >= size ||
792 				       st->status != SMB_DIRECT_CS_CONNECTED);
793 	if (rc)
794 		return -EINTR;
795 
796 	goto again;
797 }
798 
799 static void smb_direct_post_recv_credits(struct work_struct *work)
800 {
801 	struct smb_direct_transport *t = container_of(work,
802 		struct smb_direct_transport, post_recv_credits_work);
803 	struct smb_direct_recvmsg *recvmsg;
804 	int receive_credits, credits = 0;
805 	int ret;
806 
807 	spin_lock(&t->receive_credit_lock);
808 	receive_credits = t->recv_credits;
809 	spin_unlock(&t->receive_credit_lock);
810 
811 	if (receive_credits < t->recv_credit_target) {
812 		while (true) {
813 			recvmsg = get_free_recvmsg(t);
814 			if (!recvmsg)
815 				break;
816 
817 			recvmsg->type = SMB_DIRECT_MSG_DATA_TRANSFER;
818 			recvmsg->first_segment = false;
819 
820 			ret = smb_direct_post_recv(t, recvmsg);
821 			if (ret) {
822 				pr_err("Can't post recv: %d\n", ret);
823 				put_recvmsg(t, recvmsg);
824 				break;
825 			}
826 			credits++;
827 		}
828 	}
829 
830 	spin_lock(&t->receive_credit_lock);
831 	t->recv_credits += credits;
832 	t->count_avail_recvmsg -= credits;
833 	spin_unlock(&t->receive_credit_lock);
834 
835 	spin_lock(&t->lock_new_recv_credits);
836 	t->new_recv_credits += credits;
837 	spin_unlock(&t->lock_new_recv_credits);
838 
839 	if (credits)
840 		queue_work(smb_direct_wq, &t->send_immediate_work);
841 }
842 
843 static void send_done(struct ib_cq *cq, struct ib_wc *wc)
844 {
845 	struct smb_direct_sendmsg *sendmsg, *sibling;
846 	struct smb_direct_transport *t;
847 	struct list_head *pos, *prev, *end;
848 
849 	sendmsg = container_of(wc->wr_cqe, struct smb_direct_sendmsg, cqe);
850 	t = sendmsg->transport;
851 
852 	ksmbd_debug(RDMA, "Send completed. status='%s (%d)', opcode=%d\n",
853 		    ib_wc_status_msg(wc->status), wc->status,
854 		    wc->opcode);
855 
856 	if (wc->status != IB_WC_SUCCESS || wc->opcode != IB_WC_SEND) {
857 		pr_err("Send error. status='%s (%d)', opcode=%d\n",
858 		       ib_wc_status_msg(wc->status), wc->status,
859 		       wc->opcode);
860 		smb_direct_disconnect_rdma_connection(t);
861 	}
862 
863 	if (atomic_dec_and_test(&t->send_pending))
864 		wake_up(&t->wait_send_pending);
865 
866 	/* iterate and free the list of messages in reverse. the list's head
867 	 * is invalid.
868 	 */
869 	for (pos = &sendmsg->list, prev = pos->prev, end = sendmsg->list.next;
870 	     prev != end; pos = prev, prev = prev->prev) {
871 		sibling = container_of(pos, struct smb_direct_sendmsg, list);
872 		smb_direct_free_sendmsg(t, sibling);
873 	}
874 
875 	sibling = container_of(pos, struct smb_direct_sendmsg, list);
876 	smb_direct_free_sendmsg(t, sibling);
877 }
878 
879 static int manage_credits_prior_sending(struct smb_direct_transport *t)
880 {
881 	int new_credits;
882 
883 	spin_lock(&t->lock_new_recv_credits);
884 	new_credits = t->new_recv_credits;
885 	t->new_recv_credits = 0;
886 	spin_unlock(&t->lock_new_recv_credits);
887 
888 	return new_credits;
889 }
890 
891 static int smb_direct_post_send(struct smb_direct_transport *t,
892 				struct ib_send_wr *wr)
893 {
894 	int ret;
895 
896 	atomic_inc(&t->send_pending);
897 	ret = ib_post_send(t->qp, wr, NULL);
898 	if (ret) {
899 		pr_err("failed to post send: %d\n", ret);
900 		if (atomic_dec_and_test(&t->send_pending))
901 			wake_up(&t->wait_send_pending);
902 		smb_direct_disconnect_rdma_connection(t);
903 	}
904 	return ret;
905 }
906 
907 static void smb_direct_send_ctx_init(struct smb_direct_transport *t,
908 				     struct smb_direct_send_ctx *send_ctx,
909 				     bool need_invalidate_rkey,
910 				     unsigned int remote_key)
911 {
912 	INIT_LIST_HEAD(&send_ctx->msg_list);
913 	send_ctx->wr_cnt = 0;
914 	send_ctx->need_invalidate_rkey = need_invalidate_rkey;
915 	send_ctx->remote_key = remote_key;
916 }
917 
918 static int smb_direct_flush_send_list(struct smb_direct_transport *t,
919 				      struct smb_direct_send_ctx *send_ctx,
920 				      bool is_last)
921 {
922 	struct smb_direct_sendmsg *first, *last;
923 	int ret;
924 
925 	if (list_empty(&send_ctx->msg_list))
926 		return 0;
927 
928 	first = list_first_entry(&send_ctx->msg_list,
929 				 struct smb_direct_sendmsg,
930 				 list);
931 	last = list_last_entry(&send_ctx->msg_list,
932 			       struct smb_direct_sendmsg,
933 			       list);
934 
935 	last->wr.send_flags = IB_SEND_SIGNALED;
936 	last->wr.wr_cqe = &last->cqe;
937 	if (is_last && send_ctx->need_invalidate_rkey) {
938 		last->wr.opcode = IB_WR_SEND_WITH_INV;
939 		last->wr.ex.invalidate_rkey = send_ctx->remote_key;
940 	}
941 
942 	ret = smb_direct_post_send(t, &first->wr);
943 	if (!ret) {
944 		smb_direct_send_ctx_init(t, send_ctx,
945 					 send_ctx->need_invalidate_rkey,
946 					 send_ctx->remote_key);
947 	} else {
948 		atomic_add(send_ctx->wr_cnt, &t->send_credits);
949 		wake_up(&t->wait_send_credits);
950 		list_for_each_entry_safe(first, last, &send_ctx->msg_list,
951 					 list) {
952 			smb_direct_free_sendmsg(t, first);
953 		}
954 	}
955 	return ret;
956 }
957 
958 static int wait_for_credits(struct smb_direct_transport *t,
959 			    wait_queue_head_t *waitq, atomic_t *total_credits,
960 			    int needed)
961 {
962 	int ret;
963 
964 	do {
965 		if (atomic_sub_return(needed, total_credits) >= 0)
966 			return 0;
967 
968 		atomic_add(needed, total_credits);
969 		ret = wait_event_interruptible(*waitq,
970 					       atomic_read(total_credits) >= needed ||
971 					       t->status != SMB_DIRECT_CS_CONNECTED);
972 
973 		if (t->status != SMB_DIRECT_CS_CONNECTED)
974 			return -ENOTCONN;
975 		else if (ret < 0)
976 			return ret;
977 	} while (true);
978 }
979 
980 static int wait_for_send_credits(struct smb_direct_transport *t,
981 				 struct smb_direct_send_ctx *send_ctx)
982 {
983 	int ret;
984 
985 	if (send_ctx &&
986 	    (send_ctx->wr_cnt >= 16 || atomic_read(&t->send_credits) <= 1)) {
987 		ret = smb_direct_flush_send_list(t, send_ctx, false);
988 		if (ret)
989 			return ret;
990 	}
991 
992 	return wait_for_credits(t, &t->wait_send_credits, &t->send_credits, 1);
993 }
994 
995 static int wait_for_rw_credits(struct smb_direct_transport *t, int credits)
996 {
997 	return wait_for_credits(t, &t->wait_rw_credits, &t->rw_credits, credits);
998 }
999 
1000 static int calc_rw_credits(struct smb_direct_transport *t,
1001 			   char *buf, unsigned int len)
1002 {
1003 	return DIV_ROUND_UP(get_buf_page_count(buf, len),
1004 			    t->pages_per_rw_credit);
1005 }
1006 
1007 static int smb_direct_create_header(struct smb_direct_transport *t,
1008 				    int size, int remaining_data_length,
1009 				    struct smb_direct_sendmsg **sendmsg_out)
1010 {
1011 	struct smb_direct_sendmsg *sendmsg;
1012 	struct smb_direct_data_transfer *packet;
1013 	int header_length;
1014 	int ret;
1015 
1016 	sendmsg = smb_direct_alloc_sendmsg(t);
1017 	if (IS_ERR(sendmsg))
1018 		return PTR_ERR(sendmsg);
1019 
1020 	/* Fill in the packet header */
1021 	packet = (struct smb_direct_data_transfer *)sendmsg->packet;
1022 	packet->credits_requested = cpu_to_le16(t->send_credit_target);
1023 	packet->credits_granted = cpu_to_le16(manage_credits_prior_sending(t));
1024 
1025 	packet->flags = 0;
1026 	packet->reserved = 0;
1027 	if (!size)
1028 		packet->data_offset = 0;
1029 	else
1030 		packet->data_offset = cpu_to_le32(24);
1031 	packet->data_length = cpu_to_le32(size);
1032 	packet->remaining_data_length = cpu_to_le32(remaining_data_length);
1033 	packet->padding = 0;
1034 
1035 	ksmbd_debug(RDMA,
1036 		    "credits_requested=%d credits_granted=%d data_offset=%d data_length=%d remaining_data_length=%d\n",
1037 		    le16_to_cpu(packet->credits_requested),
1038 		    le16_to_cpu(packet->credits_granted),
1039 		    le32_to_cpu(packet->data_offset),
1040 		    le32_to_cpu(packet->data_length),
1041 		    le32_to_cpu(packet->remaining_data_length));
1042 
1043 	/* Map the packet to DMA */
1044 	header_length = sizeof(struct smb_direct_data_transfer);
1045 	/* If this is a packet without payload, don't send padding */
1046 	if (!size)
1047 		header_length =
1048 			offsetof(struct smb_direct_data_transfer, padding);
1049 
1050 	sendmsg->sge[0].addr = ib_dma_map_single(t->cm_id->device,
1051 						 (void *)packet,
1052 						 header_length,
1053 						 DMA_TO_DEVICE);
1054 	ret = ib_dma_mapping_error(t->cm_id->device, sendmsg->sge[0].addr);
1055 	if (ret) {
1056 		smb_direct_free_sendmsg(t, sendmsg);
1057 		return ret;
1058 	}
1059 
1060 	sendmsg->num_sge = 1;
1061 	sendmsg->sge[0].length = header_length;
1062 	sendmsg->sge[0].lkey = t->pd->local_dma_lkey;
1063 
1064 	*sendmsg_out = sendmsg;
1065 	return 0;
1066 }
1067 
1068 static int get_sg_list(void *buf, int size, struct scatterlist *sg_list, int nentries)
1069 {
1070 	bool high = is_vmalloc_addr(buf);
1071 	struct page *page;
1072 	int offset, len;
1073 	int i = 0;
1074 
1075 	if (size <= 0 || nentries < get_buf_page_count(buf, size))
1076 		return -EINVAL;
1077 
1078 	offset = offset_in_page(buf);
1079 	buf -= offset;
1080 	while (size > 0) {
1081 		len = min_t(int, PAGE_SIZE - offset, size);
1082 		if (high)
1083 			page = vmalloc_to_page(buf);
1084 		else
1085 			page = kmap_to_page(buf);
1086 
1087 		if (!sg_list)
1088 			return -EINVAL;
1089 		sg_set_page(sg_list, page, len, offset);
1090 		sg_list = sg_next(sg_list);
1091 
1092 		buf += PAGE_SIZE;
1093 		size -= len;
1094 		offset = 0;
1095 		i++;
1096 	}
1097 	return i;
1098 }
1099 
1100 static int get_mapped_sg_list(struct ib_device *device, void *buf, int size,
1101 			      struct scatterlist *sg_list, int nentries,
1102 			      enum dma_data_direction dir)
1103 {
1104 	int npages;
1105 
1106 	npages = get_sg_list(buf, size, sg_list, nentries);
1107 	if (npages < 0)
1108 		return -EINVAL;
1109 	return ib_dma_map_sg(device, sg_list, npages, dir);
1110 }
1111 
1112 static int post_sendmsg(struct smb_direct_transport *t,
1113 			struct smb_direct_send_ctx *send_ctx,
1114 			struct smb_direct_sendmsg *msg)
1115 {
1116 	int i;
1117 
1118 	for (i = 0; i < msg->num_sge; i++)
1119 		ib_dma_sync_single_for_device(t->cm_id->device,
1120 					      msg->sge[i].addr, msg->sge[i].length,
1121 					      DMA_TO_DEVICE);
1122 
1123 	msg->cqe.done = send_done;
1124 	msg->wr.opcode = IB_WR_SEND;
1125 	msg->wr.sg_list = &msg->sge[0];
1126 	msg->wr.num_sge = msg->num_sge;
1127 	msg->wr.next = NULL;
1128 
1129 	if (send_ctx) {
1130 		msg->wr.wr_cqe = NULL;
1131 		msg->wr.send_flags = 0;
1132 		if (!list_empty(&send_ctx->msg_list)) {
1133 			struct smb_direct_sendmsg *last;
1134 
1135 			last = list_last_entry(&send_ctx->msg_list,
1136 					       struct smb_direct_sendmsg,
1137 					       list);
1138 			last->wr.next = &msg->wr;
1139 		}
1140 		list_add_tail(&msg->list, &send_ctx->msg_list);
1141 		send_ctx->wr_cnt++;
1142 		return 0;
1143 	}
1144 
1145 	msg->wr.wr_cqe = &msg->cqe;
1146 	msg->wr.send_flags = IB_SEND_SIGNALED;
1147 	return smb_direct_post_send(t, &msg->wr);
1148 }
1149 
1150 static int smb_direct_post_send_data(struct smb_direct_transport *t,
1151 				     struct smb_direct_send_ctx *send_ctx,
1152 				     struct kvec *iov, int niov,
1153 				     int remaining_data_length)
1154 {
1155 	int i, j, ret;
1156 	struct smb_direct_sendmsg *msg;
1157 	int data_length;
1158 	struct scatterlist sg[SMB_DIRECT_MAX_SEND_SGES - 1];
1159 
1160 	ret = wait_for_send_credits(t, send_ctx);
1161 	if (ret)
1162 		return ret;
1163 
1164 	data_length = 0;
1165 	for (i = 0; i < niov; i++)
1166 		data_length += iov[i].iov_len;
1167 
1168 	ret = smb_direct_create_header(t, data_length, remaining_data_length,
1169 				       &msg);
1170 	if (ret) {
1171 		atomic_inc(&t->send_credits);
1172 		return ret;
1173 	}
1174 
1175 	for (i = 0; i < niov; i++) {
1176 		struct ib_sge *sge;
1177 		int sg_cnt;
1178 
1179 		sg_init_table(sg, SMB_DIRECT_MAX_SEND_SGES - 1);
1180 		sg_cnt = get_mapped_sg_list(t->cm_id->device,
1181 					    iov[i].iov_base, iov[i].iov_len,
1182 					    sg, SMB_DIRECT_MAX_SEND_SGES - 1,
1183 					    DMA_TO_DEVICE);
1184 		if (sg_cnt <= 0) {
1185 			pr_err("failed to map buffer\n");
1186 			ret = -ENOMEM;
1187 			goto err;
1188 		} else if (sg_cnt + msg->num_sge > SMB_DIRECT_MAX_SEND_SGES) {
1189 			pr_err("buffer not fitted into sges\n");
1190 			ret = -E2BIG;
1191 			ib_dma_unmap_sg(t->cm_id->device, sg, sg_cnt,
1192 					DMA_TO_DEVICE);
1193 			goto err;
1194 		}
1195 
1196 		for (j = 0; j < sg_cnt; j++) {
1197 			sge = &msg->sge[msg->num_sge];
1198 			sge->addr = sg_dma_address(&sg[j]);
1199 			sge->length = sg_dma_len(&sg[j]);
1200 			sge->lkey  = t->pd->local_dma_lkey;
1201 			msg->num_sge++;
1202 		}
1203 	}
1204 
1205 	ret = post_sendmsg(t, send_ctx, msg);
1206 	if (ret)
1207 		goto err;
1208 	return 0;
1209 err:
1210 	smb_direct_free_sendmsg(t, msg);
1211 	atomic_inc(&t->send_credits);
1212 	return ret;
1213 }
1214 
1215 static int smb_direct_writev(struct ksmbd_transport *t,
1216 			     struct kvec *iov, int niovs, int buflen,
1217 			     bool need_invalidate, unsigned int remote_key)
1218 {
1219 	struct smb_direct_transport *st = smb_trans_direct_transfort(t);
1220 	size_t remaining_data_length;
1221 	size_t iov_idx;
1222 	size_t iov_ofs;
1223 	size_t max_iov_size = st->max_send_size -
1224 			sizeof(struct smb_direct_data_transfer);
1225 	int ret;
1226 	struct smb_direct_send_ctx send_ctx;
1227 	int error = 0;
1228 
1229 	if (st->status != SMB_DIRECT_CS_CONNECTED)
1230 		return -ENOTCONN;
1231 
1232 	//FIXME: skip RFC1002 header..
1233 	if (WARN_ON_ONCE(niovs <= 1 || iov[0].iov_len != 4))
1234 		return -EINVAL;
1235 	buflen -= 4;
1236 	iov_idx = 1;
1237 	iov_ofs = 0;
1238 
1239 	remaining_data_length = buflen;
1240 	ksmbd_debug(RDMA, "Sending smb (RDMA): smb_len=%u\n", buflen);
1241 
1242 	smb_direct_send_ctx_init(st, &send_ctx, need_invalidate, remote_key);
1243 	while (remaining_data_length) {
1244 		struct kvec vecs[SMB_DIRECT_MAX_SEND_SGES - 1]; /* minus smbdirect hdr */
1245 		size_t possible_bytes = max_iov_size;
1246 		size_t possible_vecs;
1247 		size_t bytes = 0;
1248 		size_t nvecs = 0;
1249 
1250 		/*
1251 		 * For the last message remaining_data_length should be
1252 		 * have been 0 already!
1253 		 */
1254 		if (WARN_ON_ONCE(iov_idx >= niovs)) {
1255 			error = -EINVAL;
1256 			goto done;
1257 		}
1258 
1259 		/*
1260 		 * We have 2 factors which limit the arguments we pass
1261 		 * to smb_direct_post_send_data():
1262 		 *
1263 		 * 1. The number of supported sges for the send,
1264 		 *    while one is reserved for the smbdirect header.
1265 		 *    And we currently need one SGE per page.
1266 		 * 2. The number of negotiated payload bytes per send.
1267 		 */
1268 		possible_vecs = min_t(size_t, ARRAY_SIZE(vecs), niovs - iov_idx);
1269 
1270 		while (iov_idx < niovs && possible_vecs && possible_bytes) {
1271 			struct kvec *v = &vecs[nvecs];
1272 			int page_count;
1273 
1274 			v->iov_base = ((u8 *)iov[iov_idx].iov_base) + iov_ofs;
1275 			v->iov_len = min_t(size_t,
1276 					   iov[iov_idx].iov_len - iov_ofs,
1277 					   possible_bytes);
1278 			page_count = get_buf_page_count(v->iov_base, v->iov_len);
1279 			if (page_count > possible_vecs) {
1280 				/*
1281 				 * If the number of pages in the buffer
1282 				 * is to much (because we currently require
1283 				 * one SGE per page), we need to limit the
1284 				 * length.
1285 				 *
1286 				 * We know possible_vecs is at least 1,
1287 				 * so we always keep the first page.
1288 				 *
1289 				 * We need to calculate the number extra
1290 				 * pages (epages) we can also keep.
1291 				 *
1292 				 * We calculate the number of bytes in the
1293 				 * first page (fplen), this should never be
1294 				 * larger than v->iov_len because page_count is
1295 				 * at least 2, but adding a limitation feels
1296 				 * better.
1297 				 *
1298 				 * Then we calculate the number of bytes (elen)
1299 				 * we can keep for the extra pages.
1300 				 */
1301 				size_t epages = possible_vecs - 1;
1302 				size_t fpofs = offset_in_page(v->iov_base);
1303 				size_t fplen = min_t(size_t, PAGE_SIZE - fpofs, v->iov_len);
1304 				size_t elen = min_t(size_t, v->iov_len - fplen, epages*PAGE_SIZE);
1305 
1306 				v->iov_len = fplen + elen;
1307 				page_count = get_buf_page_count(v->iov_base, v->iov_len);
1308 				if (WARN_ON_ONCE(page_count > possible_vecs)) {
1309 					/*
1310 					 * Something went wrong in the above
1311 					 * logic...
1312 					 */
1313 					error = -EINVAL;
1314 					goto done;
1315 				}
1316 			}
1317 			possible_vecs -= page_count;
1318 			nvecs += 1;
1319 			possible_bytes -= v->iov_len;
1320 			bytes += v->iov_len;
1321 
1322 			iov_ofs += v->iov_len;
1323 			if (iov_ofs >= iov[iov_idx].iov_len) {
1324 				iov_idx += 1;
1325 				iov_ofs = 0;
1326 			}
1327 		}
1328 
1329 		remaining_data_length -= bytes;
1330 
1331 		ret = smb_direct_post_send_data(st, &send_ctx,
1332 						vecs, nvecs,
1333 						remaining_data_length);
1334 		if (unlikely(ret)) {
1335 			error = ret;
1336 			goto done;
1337 		}
1338 	}
1339 
1340 done:
1341 	ret = smb_direct_flush_send_list(st, &send_ctx, true);
1342 	if (unlikely(!ret && error))
1343 		ret = error;
1344 
1345 	/*
1346 	 * As an optimization, we don't wait for individual I/O to finish
1347 	 * before sending the next one.
1348 	 * Send them all and wait for pending send count to get to 0
1349 	 * that means all the I/Os have been out and we are good to return
1350 	 */
1351 
1352 	wait_event(st->wait_send_pending,
1353 		   atomic_read(&st->send_pending) == 0);
1354 	return ret;
1355 }
1356 
1357 static void smb_direct_free_rdma_rw_msg(struct smb_direct_transport *t,
1358 					struct smb_direct_rdma_rw_msg *msg,
1359 					enum dma_data_direction dir)
1360 {
1361 	rdma_rw_ctx_destroy(&msg->rw_ctx, t->qp, t->qp->port,
1362 			    msg->sgt.sgl, msg->sgt.nents, dir);
1363 	sg_free_table_chained(&msg->sgt, SG_CHUNK_SIZE);
1364 	kfree(msg);
1365 }
1366 
1367 static void read_write_done(struct ib_cq *cq, struct ib_wc *wc,
1368 			    enum dma_data_direction dir)
1369 {
1370 	struct smb_direct_rdma_rw_msg *msg = container_of(wc->wr_cqe,
1371 							  struct smb_direct_rdma_rw_msg, cqe);
1372 	struct smb_direct_transport *t = msg->t;
1373 
1374 	if (wc->status != IB_WC_SUCCESS) {
1375 		msg->status = -EIO;
1376 		pr_err("read/write error. opcode = %d, status = %s(%d)\n",
1377 		       wc->opcode, ib_wc_status_msg(wc->status), wc->status);
1378 		if (wc->status != IB_WC_WR_FLUSH_ERR)
1379 			smb_direct_disconnect_rdma_connection(t);
1380 	}
1381 
1382 	complete(msg->completion);
1383 }
1384 
1385 static void read_done(struct ib_cq *cq, struct ib_wc *wc)
1386 {
1387 	read_write_done(cq, wc, DMA_FROM_DEVICE);
1388 }
1389 
1390 static void write_done(struct ib_cq *cq, struct ib_wc *wc)
1391 {
1392 	read_write_done(cq, wc, DMA_TO_DEVICE);
1393 }
1394 
1395 static int smb_direct_rdma_xmit(struct smb_direct_transport *t,
1396 				void *buf, int buf_len,
1397 				struct smb2_buffer_desc_v1 *desc,
1398 				unsigned int desc_len,
1399 				bool is_read)
1400 {
1401 	struct smb_direct_rdma_rw_msg *msg, *next_msg;
1402 	int i, ret;
1403 	DECLARE_COMPLETION_ONSTACK(completion);
1404 	struct ib_send_wr *first_wr;
1405 	LIST_HEAD(msg_list);
1406 	char *desc_buf;
1407 	int credits_needed;
1408 	unsigned int desc_buf_len, desc_num = 0;
1409 
1410 	if (t->status != SMB_DIRECT_CS_CONNECTED)
1411 		return -ENOTCONN;
1412 
1413 	if (buf_len > t->max_rdma_rw_size)
1414 		return -EINVAL;
1415 
1416 	/* calculate needed credits */
1417 	credits_needed = 0;
1418 	desc_buf = buf;
1419 	for (i = 0; i < desc_len / sizeof(*desc); i++) {
1420 		if (!buf_len)
1421 			break;
1422 
1423 		desc_buf_len = le32_to_cpu(desc[i].length);
1424 		if (!desc_buf_len)
1425 			return -EINVAL;
1426 
1427 		if (desc_buf_len > buf_len) {
1428 			desc_buf_len = buf_len;
1429 			desc[i].length = cpu_to_le32(desc_buf_len);
1430 			buf_len = 0;
1431 		}
1432 
1433 		credits_needed += calc_rw_credits(t, desc_buf, desc_buf_len);
1434 		desc_buf += desc_buf_len;
1435 		buf_len -= desc_buf_len;
1436 		desc_num++;
1437 	}
1438 
1439 	ksmbd_debug(RDMA, "RDMA %s, len %#x, needed credits %#x\n",
1440 		    str_read_write(is_read), buf_len, credits_needed);
1441 
1442 	ret = wait_for_rw_credits(t, credits_needed);
1443 	if (ret < 0)
1444 		return ret;
1445 
1446 	/* build rdma_rw_ctx for each descriptor */
1447 	desc_buf = buf;
1448 	for (i = 0; i < desc_num; i++) {
1449 		msg = kzalloc(struct_size(msg, sg_list, SG_CHUNK_SIZE),
1450 			      KSMBD_DEFAULT_GFP);
1451 		if (!msg) {
1452 			ret = -ENOMEM;
1453 			goto out;
1454 		}
1455 
1456 		desc_buf_len = le32_to_cpu(desc[i].length);
1457 
1458 		msg->t = t;
1459 		msg->cqe.done = is_read ? read_done : write_done;
1460 		msg->completion = &completion;
1461 
1462 		msg->sgt.sgl = &msg->sg_list[0];
1463 		ret = sg_alloc_table_chained(&msg->sgt,
1464 					     get_buf_page_count(desc_buf, desc_buf_len),
1465 					     msg->sg_list, SG_CHUNK_SIZE);
1466 		if (ret) {
1467 			kfree(msg);
1468 			ret = -ENOMEM;
1469 			goto out;
1470 		}
1471 
1472 		ret = get_sg_list(desc_buf, desc_buf_len,
1473 				  msg->sgt.sgl, msg->sgt.orig_nents);
1474 		if (ret < 0) {
1475 			sg_free_table_chained(&msg->sgt, SG_CHUNK_SIZE);
1476 			kfree(msg);
1477 			goto out;
1478 		}
1479 
1480 		ret = rdma_rw_ctx_init(&msg->rw_ctx, t->qp, t->qp->port,
1481 				       msg->sgt.sgl,
1482 				       get_buf_page_count(desc_buf, desc_buf_len),
1483 				       0,
1484 				       le64_to_cpu(desc[i].offset),
1485 				       le32_to_cpu(desc[i].token),
1486 				       is_read ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
1487 		if (ret < 0) {
1488 			pr_err("failed to init rdma_rw_ctx: %d\n", ret);
1489 			sg_free_table_chained(&msg->sgt, SG_CHUNK_SIZE);
1490 			kfree(msg);
1491 			goto out;
1492 		}
1493 
1494 		list_add_tail(&msg->list, &msg_list);
1495 		desc_buf += desc_buf_len;
1496 	}
1497 
1498 	/* concatenate work requests of rdma_rw_ctxs */
1499 	first_wr = NULL;
1500 	list_for_each_entry_reverse(msg, &msg_list, list) {
1501 		first_wr = rdma_rw_ctx_wrs(&msg->rw_ctx, t->qp, t->qp->port,
1502 					   &msg->cqe, first_wr);
1503 	}
1504 
1505 	ret = ib_post_send(t->qp, first_wr, NULL);
1506 	if (ret) {
1507 		pr_err("failed to post send wr for RDMA R/W: %d\n", ret);
1508 		goto out;
1509 	}
1510 
1511 	msg = list_last_entry(&msg_list, struct smb_direct_rdma_rw_msg, list);
1512 	wait_for_completion(&completion);
1513 	ret = msg->status;
1514 out:
1515 	list_for_each_entry_safe(msg, next_msg, &msg_list, list) {
1516 		list_del(&msg->list);
1517 		smb_direct_free_rdma_rw_msg(t, msg,
1518 					    is_read ? DMA_FROM_DEVICE : DMA_TO_DEVICE);
1519 	}
1520 	atomic_add(credits_needed, &t->rw_credits);
1521 	wake_up(&t->wait_rw_credits);
1522 	return ret;
1523 }
1524 
1525 static int smb_direct_rdma_write(struct ksmbd_transport *t,
1526 				 void *buf, unsigned int buflen,
1527 				 struct smb2_buffer_desc_v1 *desc,
1528 				 unsigned int desc_len)
1529 {
1530 	return smb_direct_rdma_xmit(smb_trans_direct_transfort(t), buf, buflen,
1531 				    desc, desc_len, false);
1532 }
1533 
1534 static int smb_direct_rdma_read(struct ksmbd_transport *t,
1535 				void *buf, unsigned int buflen,
1536 				struct smb2_buffer_desc_v1 *desc,
1537 				unsigned int desc_len)
1538 {
1539 	return smb_direct_rdma_xmit(smb_trans_direct_transfort(t), buf, buflen,
1540 				    desc, desc_len, true);
1541 }
1542 
1543 static void smb_direct_disconnect(struct ksmbd_transport *t)
1544 {
1545 	struct smb_direct_transport *st = smb_trans_direct_transfort(t);
1546 
1547 	ksmbd_debug(RDMA, "Disconnecting cm_id=%p\n", st->cm_id);
1548 
1549 	smb_direct_disconnect_rdma_work(&st->disconnect_work);
1550 	wait_event_interruptible(st->wait_status,
1551 				 st->status == SMB_DIRECT_CS_DISCONNECTED);
1552 	free_transport(st);
1553 }
1554 
1555 static void smb_direct_shutdown(struct ksmbd_transport *t)
1556 {
1557 	struct smb_direct_transport *st = smb_trans_direct_transfort(t);
1558 
1559 	ksmbd_debug(RDMA, "smb-direct shutdown cm_id=%p\n", st->cm_id);
1560 
1561 	smb_direct_disconnect_rdma_work(&st->disconnect_work);
1562 }
1563 
1564 static int smb_direct_cm_handler(struct rdma_cm_id *cm_id,
1565 				 struct rdma_cm_event *event)
1566 {
1567 	struct smb_direct_transport *t = cm_id->context;
1568 
1569 	ksmbd_debug(RDMA, "RDMA CM event. cm_id=%p event=%s (%d)\n",
1570 		    cm_id, rdma_event_msg(event->event), event->event);
1571 
1572 	switch (event->event) {
1573 	case RDMA_CM_EVENT_ESTABLISHED: {
1574 		t->status = SMB_DIRECT_CS_CONNECTED;
1575 		wake_up_interruptible(&t->wait_status);
1576 		break;
1577 	}
1578 	case RDMA_CM_EVENT_DEVICE_REMOVAL:
1579 	case RDMA_CM_EVENT_DISCONNECTED: {
1580 		ib_drain_qp(t->qp);
1581 
1582 		t->status = SMB_DIRECT_CS_DISCONNECTED;
1583 		wake_up_interruptible(&t->wait_status);
1584 		wake_up_interruptible(&t->wait_reassembly_queue);
1585 		wake_up(&t->wait_send_credits);
1586 		break;
1587 	}
1588 	case RDMA_CM_EVENT_CONNECT_ERROR: {
1589 		t->status = SMB_DIRECT_CS_DISCONNECTED;
1590 		wake_up_interruptible(&t->wait_status);
1591 		break;
1592 	}
1593 	default:
1594 		pr_err("Unexpected RDMA CM event. cm_id=%p, event=%s (%d)\n",
1595 		       cm_id, rdma_event_msg(event->event),
1596 		       event->event);
1597 		break;
1598 	}
1599 	return 0;
1600 }
1601 
1602 static void smb_direct_qpair_handler(struct ib_event *event, void *context)
1603 {
1604 	struct smb_direct_transport *t = context;
1605 
1606 	ksmbd_debug(RDMA, "Received QP event. cm_id=%p, event=%s (%d)\n",
1607 		    t->cm_id, ib_event_msg(event->event), event->event);
1608 
1609 	switch (event->event) {
1610 	case IB_EVENT_CQ_ERR:
1611 	case IB_EVENT_QP_FATAL:
1612 		smb_direct_disconnect_rdma_connection(t);
1613 		break;
1614 	default:
1615 		break;
1616 	}
1617 }
1618 
1619 static int smb_direct_send_negotiate_response(struct smb_direct_transport *t,
1620 					      int failed)
1621 {
1622 	struct smb_direct_sendmsg *sendmsg;
1623 	struct smb_direct_negotiate_resp *resp;
1624 	int ret;
1625 
1626 	sendmsg = smb_direct_alloc_sendmsg(t);
1627 	if (IS_ERR(sendmsg))
1628 		return -ENOMEM;
1629 
1630 	resp = (struct smb_direct_negotiate_resp *)sendmsg->packet;
1631 	if (failed) {
1632 		memset(resp, 0, sizeof(*resp));
1633 		resp->min_version = cpu_to_le16(0x0100);
1634 		resp->max_version = cpu_to_le16(0x0100);
1635 		resp->status = STATUS_NOT_SUPPORTED;
1636 	} else {
1637 		resp->status = STATUS_SUCCESS;
1638 		resp->min_version = SMB_DIRECT_VERSION_LE;
1639 		resp->max_version = SMB_DIRECT_VERSION_LE;
1640 		resp->negotiated_version = SMB_DIRECT_VERSION_LE;
1641 		resp->reserved = 0;
1642 		resp->credits_requested =
1643 				cpu_to_le16(t->send_credit_target);
1644 		resp->credits_granted = cpu_to_le16(manage_credits_prior_sending(t));
1645 		resp->max_readwrite_size = cpu_to_le32(t->max_rdma_rw_size);
1646 		resp->preferred_send_size = cpu_to_le32(t->max_send_size);
1647 		resp->max_receive_size = cpu_to_le32(t->max_recv_size);
1648 		resp->max_fragmented_size =
1649 				cpu_to_le32(t->max_fragmented_recv_size);
1650 	}
1651 
1652 	sendmsg->sge[0].addr = ib_dma_map_single(t->cm_id->device,
1653 						 (void *)resp, sizeof(*resp),
1654 						 DMA_TO_DEVICE);
1655 	ret = ib_dma_mapping_error(t->cm_id->device, sendmsg->sge[0].addr);
1656 	if (ret) {
1657 		smb_direct_free_sendmsg(t, sendmsg);
1658 		return ret;
1659 	}
1660 
1661 	sendmsg->num_sge = 1;
1662 	sendmsg->sge[0].length = sizeof(*resp);
1663 	sendmsg->sge[0].lkey = t->pd->local_dma_lkey;
1664 
1665 	ret = post_sendmsg(t, NULL, sendmsg);
1666 	if (ret) {
1667 		smb_direct_free_sendmsg(t, sendmsg);
1668 		return ret;
1669 	}
1670 
1671 	wait_event(t->wait_send_pending,
1672 		   atomic_read(&t->send_pending) == 0);
1673 	return 0;
1674 }
1675 
1676 static int smb_direct_accept_client(struct smb_direct_transport *t)
1677 {
1678 	struct rdma_conn_param conn_param;
1679 	struct ib_port_immutable port_immutable;
1680 	u32 ird_ord_hdr[2];
1681 	int ret;
1682 
1683 	memset(&conn_param, 0, sizeof(conn_param));
1684 	conn_param.initiator_depth = min_t(u8, t->cm_id->device->attrs.max_qp_rd_atom,
1685 					   SMB_DIRECT_CM_INITIATOR_DEPTH);
1686 	conn_param.responder_resources = 0;
1687 
1688 	t->cm_id->device->ops.get_port_immutable(t->cm_id->device,
1689 						 t->cm_id->port_num,
1690 						 &port_immutable);
1691 	if (port_immutable.core_cap_flags & RDMA_CORE_PORT_IWARP) {
1692 		ird_ord_hdr[0] = conn_param.responder_resources;
1693 		ird_ord_hdr[1] = 1;
1694 		conn_param.private_data = ird_ord_hdr;
1695 		conn_param.private_data_len = sizeof(ird_ord_hdr);
1696 	} else {
1697 		conn_param.private_data = NULL;
1698 		conn_param.private_data_len = 0;
1699 	}
1700 	conn_param.retry_count = SMB_DIRECT_CM_RETRY;
1701 	conn_param.rnr_retry_count = SMB_DIRECT_CM_RNR_RETRY;
1702 	conn_param.flow_control = 0;
1703 
1704 	ret = rdma_accept(t->cm_id, &conn_param);
1705 	if (ret) {
1706 		pr_err("error at rdma_accept: %d\n", ret);
1707 		return ret;
1708 	}
1709 	return 0;
1710 }
1711 
1712 static int smb_direct_prepare_negotiation(struct smb_direct_transport *t)
1713 {
1714 	int ret;
1715 	struct smb_direct_recvmsg *recvmsg;
1716 
1717 	recvmsg = get_free_recvmsg(t);
1718 	if (!recvmsg)
1719 		return -ENOMEM;
1720 	recvmsg->type = SMB_DIRECT_MSG_NEGOTIATE_REQ;
1721 
1722 	ret = smb_direct_post_recv(t, recvmsg);
1723 	if (ret) {
1724 		pr_err("Can't post recv: %d\n", ret);
1725 		goto out_err;
1726 	}
1727 
1728 	t->negotiation_requested = false;
1729 	ret = smb_direct_accept_client(t);
1730 	if (ret) {
1731 		pr_err("Can't accept client\n");
1732 		goto out_err;
1733 	}
1734 
1735 	smb_direct_post_recv_credits(&t->post_recv_credits_work);
1736 	return 0;
1737 out_err:
1738 	put_recvmsg(t, recvmsg);
1739 	return ret;
1740 }
1741 
1742 static unsigned int smb_direct_get_max_fr_pages(struct smb_direct_transport *t)
1743 {
1744 	return min_t(unsigned int,
1745 		     t->cm_id->device->attrs.max_fast_reg_page_list_len,
1746 		     256);
1747 }
1748 
1749 static int smb_direct_init_params(struct smb_direct_transport *t,
1750 				  struct ib_qp_cap *cap)
1751 {
1752 	struct ib_device *device = t->cm_id->device;
1753 	int max_send_sges, max_rw_wrs, max_send_wrs;
1754 	unsigned int max_sge_per_wr, wrs_per_credit;
1755 
1756 	/* need 3 more sge. because a SMB_DIRECT header, SMB2 header,
1757 	 * SMB2 response could be mapped.
1758 	 */
1759 	t->max_send_size = smb_direct_max_send_size;
1760 	max_send_sges = DIV_ROUND_UP(t->max_send_size, PAGE_SIZE) + 3;
1761 	if (max_send_sges > SMB_DIRECT_MAX_SEND_SGES) {
1762 		pr_err("max_send_size %d is too large\n", t->max_send_size);
1763 		return -EINVAL;
1764 	}
1765 
1766 	/* Calculate the number of work requests for RDMA R/W.
1767 	 * The maximum number of pages which can be registered
1768 	 * with one Memory region can be transferred with one
1769 	 * R/W credit. And at least 4 work requests for each credit
1770 	 * are needed for MR registration, RDMA R/W, local & remote
1771 	 * MR invalidation.
1772 	 */
1773 	t->max_rdma_rw_size = smb_direct_max_read_write_size;
1774 	t->pages_per_rw_credit = smb_direct_get_max_fr_pages(t);
1775 	t->max_rw_credits = DIV_ROUND_UP(t->max_rdma_rw_size,
1776 					 (t->pages_per_rw_credit - 1) *
1777 					 PAGE_SIZE);
1778 
1779 	max_sge_per_wr = min_t(unsigned int, device->attrs.max_send_sge,
1780 			       device->attrs.max_sge_rd);
1781 	max_sge_per_wr = max_t(unsigned int, max_sge_per_wr,
1782 			       max_send_sges);
1783 	wrs_per_credit = max_t(unsigned int, 4,
1784 			       DIV_ROUND_UP(t->pages_per_rw_credit,
1785 					    max_sge_per_wr) + 1);
1786 	max_rw_wrs = t->max_rw_credits * wrs_per_credit;
1787 
1788 	max_send_wrs = smb_direct_send_credit_target + max_rw_wrs;
1789 	if (max_send_wrs > device->attrs.max_cqe ||
1790 	    max_send_wrs > device->attrs.max_qp_wr) {
1791 		pr_err("consider lowering send_credit_target = %d\n",
1792 		       smb_direct_send_credit_target);
1793 		pr_err("Possible CQE overrun, device reporting max_cqe %d max_qp_wr %d\n",
1794 		       device->attrs.max_cqe, device->attrs.max_qp_wr);
1795 		return -EINVAL;
1796 	}
1797 
1798 	if (smb_direct_receive_credit_max > device->attrs.max_cqe ||
1799 	    smb_direct_receive_credit_max > device->attrs.max_qp_wr) {
1800 		pr_err("consider lowering receive_credit_max = %d\n",
1801 		       smb_direct_receive_credit_max);
1802 		pr_err("Possible CQE overrun, device reporting max_cpe %d max_qp_wr %d\n",
1803 		       device->attrs.max_cqe, device->attrs.max_qp_wr);
1804 		return -EINVAL;
1805 	}
1806 
1807 	if (device->attrs.max_send_sge < SMB_DIRECT_MAX_SEND_SGES) {
1808 		pr_err("warning: device max_send_sge = %d too small\n",
1809 		       device->attrs.max_send_sge);
1810 		return -EINVAL;
1811 	}
1812 	if (device->attrs.max_recv_sge < SMB_DIRECT_MAX_RECV_SGES) {
1813 		pr_err("warning: device max_recv_sge = %d too small\n",
1814 		       device->attrs.max_recv_sge);
1815 		return -EINVAL;
1816 	}
1817 
1818 	t->recv_credits = 0;
1819 	t->count_avail_recvmsg = 0;
1820 
1821 	t->recv_credit_max = smb_direct_receive_credit_max;
1822 	t->recv_credit_target = 10;
1823 	t->new_recv_credits = 0;
1824 
1825 	t->send_credit_target = smb_direct_send_credit_target;
1826 	atomic_set(&t->send_credits, 0);
1827 	atomic_set(&t->rw_credits, t->max_rw_credits);
1828 
1829 	t->max_send_size = smb_direct_max_send_size;
1830 	t->max_recv_size = smb_direct_max_receive_size;
1831 	t->max_fragmented_recv_size = smb_direct_max_fragmented_recv_size;
1832 
1833 	cap->max_send_wr = max_send_wrs;
1834 	cap->max_recv_wr = t->recv_credit_max;
1835 	cap->max_send_sge = SMB_DIRECT_MAX_SEND_SGES;
1836 	cap->max_recv_sge = SMB_DIRECT_MAX_RECV_SGES;
1837 	cap->max_inline_data = 0;
1838 	cap->max_rdma_ctxs = t->max_rw_credits;
1839 	return 0;
1840 }
1841 
1842 static void smb_direct_destroy_pools(struct smb_direct_transport *t)
1843 {
1844 	struct smb_direct_recvmsg *recvmsg;
1845 
1846 	while ((recvmsg = get_free_recvmsg(t)))
1847 		mempool_free(recvmsg, t->recvmsg_mempool);
1848 
1849 	mempool_destroy(t->recvmsg_mempool);
1850 	t->recvmsg_mempool = NULL;
1851 
1852 	kmem_cache_destroy(t->recvmsg_cache);
1853 	t->recvmsg_cache = NULL;
1854 
1855 	mempool_destroy(t->sendmsg_mempool);
1856 	t->sendmsg_mempool = NULL;
1857 
1858 	kmem_cache_destroy(t->sendmsg_cache);
1859 	t->sendmsg_cache = NULL;
1860 }
1861 
1862 static int smb_direct_create_pools(struct smb_direct_transport *t)
1863 {
1864 	char name[80];
1865 	int i;
1866 	struct smb_direct_recvmsg *recvmsg;
1867 
1868 	snprintf(name, sizeof(name), "smb_direct_rqst_pool_%p", t);
1869 	t->sendmsg_cache = kmem_cache_create(name,
1870 					     sizeof(struct smb_direct_sendmsg) +
1871 					      sizeof(struct smb_direct_negotiate_resp),
1872 					     0, SLAB_HWCACHE_ALIGN, NULL);
1873 	if (!t->sendmsg_cache)
1874 		return -ENOMEM;
1875 
1876 	t->sendmsg_mempool = mempool_create(t->send_credit_target,
1877 					    mempool_alloc_slab, mempool_free_slab,
1878 					    t->sendmsg_cache);
1879 	if (!t->sendmsg_mempool)
1880 		goto err;
1881 
1882 	snprintf(name, sizeof(name), "smb_direct_resp_%p", t);
1883 	t->recvmsg_cache = kmem_cache_create(name,
1884 					     sizeof(struct smb_direct_recvmsg) +
1885 					      t->max_recv_size,
1886 					     0, SLAB_HWCACHE_ALIGN, NULL);
1887 	if (!t->recvmsg_cache)
1888 		goto err;
1889 
1890 	t->recvmsg_mempool =
1891 		mempool_create(t->recv_credit_max, mempool_alloc_slab,
1892 			       mempool_free_slab, t->recvmsg_cache);
1893 	if (!t->recvmsg_mempool)
1894 		goto err;
1895 
1896 	INIT_LIST_HEAD(&t->recvmsg_queue);
1897 
1898 	for (i = 0; i < t->recv_credit_max; i++) {
1899 		recvmsg = mempool_alloc(t->recvmsg_mempool, KSMBD_DEFAULT_GFP);
1900 		if (!recvmsg)
1901 			goto err;
1902 		recvmsg->transport = t;
1903 		recvmsg->sge.length = 0;
1904 		list_add(&recvmsg->list, &t->recvmsg_queue);
1905 	}
1906 	t->count_avail_recvmsg = t->recv_credit_max;
1907 
1908 	return 0;
1909 err:
1910 	smb_direct_destroy_pools(t);
1911 	return -ENOMEM;
1912 }
1913 
1914 static int smb_direct_create_qpair(struct smb_direct_transport *t,
1915 				   struct ib_qp_cap *cap)
1916 {
1917 	int ret;
1918 	struct ib_qp_init_attr qp_attr;
1919 	int pages_per_rw;
1920 
1921 	t->pd = ib_alloc_pd(t->cm_id->device, 0);
1922 	if (IS_ERR(t->pd)) {
1923 		pr_err("Can't create RDMA PD\n");
1924 		ret = PTR_ERR(t->pd);
1925 		t->pd = NULL;
1926 		return ret;
1927 	}
1928 
1929 	t->send_cq = ib_alloc_cq(t->cm_id->device, t,
1930 				 smb_direct_send_credit_target + cap->max_rdma_ctxs,
1931 				 0, IB_POLL_WORKQUEUE);
1932 	if (IS_ERR(t->send_cq)) {
1933 		pr_err("Can't create RDMA send CQ\n");
1934 		ret = PTR_ERR(t->send_cq);
1935 		t->send_cq = NULL;
1936 		goto err;
1937 	}
1938 
1939 	t->recv_cq = ib_alloc_cq(t->cm_id->device, t,
1940 				 t->recv_credit_max, 0, IB_POLL_WORKQUEUE);
1941 	if (IS_ERR(t->recv_cq)) {
1942 		pr_err("Can't create RDMA recv CQ\n");
1943 		ret = PTR_ERR(t->recv_cq);
1944 		t->recv_cq = NULL;
1945 		goto err;
1946 	}
1947 
1948 	memset(&qp_attr, 0, sizeof(qp_attr));
1949 	qp_attr.event_handler = smb_direct_qpair_handler;
1950 	qp_attr.qp_context = t;
1951 	qp_attr.cap = *cap;
1952 	qp_attr.sq_sig_type = IB_SIGNAL_REQ_WR;
1953 	qp_attr.qp_type = IB_QPT_RC;
1954 	qp_attr.send_cq = t->send_cq;
1955 	qp_attr.recv_cq = t->recv_cq;
1956 	qp_attr.port_num = ~0;
1957 
1958 	ret = rdma_create_qp(t->cm_id, t->pd, &qp_attr);
1959 	if (ret) {
1960 		pr_err("Can't create RDMA QP: %d\n", ret);
1961 		goto err;
1962 	}
1963 
1964 	t->qp = t->cm_id->qp;
1965 	t->cm_id->event_handler = smb_direct_cm_handler;
1966 
1967 	pages_per_rw = DIV_ROUND_UP(t->max_rdma_rw_size, PAGE_SIZE) + 1;
1968 	if (pages_per_rw > t->cm_id->device->attrs.max_sgl_rd) {
1969 		ret = ib_mr_pool_init(t->qp, &t->qp->rdma_mrs,
1970 				      t->max_rw_credits, IB_MR_TYPE_MEM_REG,
1971 				      t->pages_per_rw_credit, 0);
1972 		if (ret) {
1973 			pr_err("failed to init mr pool count %d pages %d\n",
1974 			       t->max_rw_credits, t->pages_per_rw_credit);
1975 			goto err;
1976 		}
1977 	}
1978 
1979 	return 0;
1980 err:
1981 	if (t->qp) {
1982 		t->qp = NULL;
1983 		rdma_destroy_qp(t->cm_id);
1984 	}
1985 	if (t->recv_cq) {
1986 		ib_destroy_cq(t->recv_cq);
1987 		t->recv_cq = NULL;
1988 	}
1989 	if (t->send_cq) {
1990 		ib_destroy_cq(t->send_cq);
1991 		t->send_cq = NULL;
1992 	}
1993 	if (t->pd) {
1994 		ib_dealloc_pd(t->pd);
1995 		t->pd = NULL;
1996 	}
1997 	return ret;
1998 }
1999 
2000 static int smb_direct_prepare(struct ksmbd_transport *t)
2001 {
2002 	struct smb_direct_transport *st = smb_trans_direct_transfort(t);
2003 	struct smb_direct_recvmsg *recvmsg;
2004 	struct smb_direct_negotiate_req *req;
2005 	int ret;
2006 
2007 	ksmbd_debug(RDMA, "Waiting for SMB_DIRECT negotiate request\n");
2008 	ret = wait_event_interruptible_timeout(st->wait_status,
2009 					       st->negotiation_requested ||
2010 					       st->status == SMB_DIRECT_CS_DISCONNECTED,
2011 					       SMB_DIRECT_NEGOTIATE_TIMEOUT * HZ);
2012 	if (ret <= 0 || st->status == SMB_DIRECT_CS_DISCONNECTED)
2013 		return ret < 0 ? ret : -ETIMEDOUT;
2014 
2015 	recvmsg = get_first_reassembly(st);
2016 	if (!recvmsg)
2017 		return -ECONNABORTED;
2018 
2019 	ret = smb_direct_check_recvmsg(recvmsg);
2020 	if (ret == -ECONNABORTED)
2021 		goto out;
2022 
2023 	req = (struct smb_direct_negotiate_req *)recvmsg->packet;
2024 	st->max_recv_size = min_t(int, st->max_recv_size,
2025 				  le32_to_cpu(req->preferred_send_size));
2026 	st->max_send_size = min_t(int, st->max_send_size,
2027 				  le32_to_cpu(req->max_receive_size));
2028 	st->max_fragmented_send_size =
2029 		le32_to_cpu(req->max_fragmented_size);
2030 	st->max_fragmented_recv_size =
2031 		(st->recv_credit_max * st->max_recv_size) / 2;
2032 
2033 	ret = smb_direct_send_negotiate_response(st, ret);
2034 out:
2035 	spin_lock_irq(&st->reassembly_queue_lock);
2036 	st->reassembly_queue_length--;
2037 	list_del(&recvmsg->list);
2038 	spin_unlock_irq(&st->reassembly_queue_lock);
2039 	put_recvmsg(st, recvmsg);
2040 
2041 	return ret;
2042 }
2043 
2044 static int smb_direct_connect(struct smb_direct_transport *st)
2045 {
2046 	int ret;
2047 	struct ib_qp_cap qp_cap;
2048 
2049 	ret = smb_direct_init_params(st, &qp_cap);
2050 	if (ret) {
2051 		pr_err("Can't configure RDMA parameters\n");
2052 		return ret;
2053 	}
2054 
2055 	ret = smb_direct_create_pools(st);
2056 	if (ret) {
2057 		pr_err("Can't init RDMA pool: %d\n", ret);
2058 		return ret;
2059 	}
2060 
2061 	ret = smb_direct_create_qpair(st, &qp_cap);
2062 	if (ret) {
2063 		pr_err("Can't accept RDMA client: %d\n", ret);
2064 		return ret;
2065 	}
2066 
2067 	ret = smb_direct_prepare_negotiation(st);
2068 	if (ret) {
2069 		pr_err("Can't negotiate: %d\n", ret);
2070 		return ret;
2071 	}
2072 	return 0;
2073 }
2074 
2075 static bool rdma_frwr_is_supported(struct ib_device_attr *attrs)
2076 {
2077 	if (!(attrs->device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS))
2078 		return false;
2079 	if (attrs->max_fast_reg_page_list_len == 0)
2080 		return false;
2081 	return true;
2082 }
2083 
2084 static int smb_direct_handle_connect_request(struct rdma_cm_id *new_cm_id)
2085 {
2086 	struct smb_direct_transport *t;
2087 	struct task_struct *handler;
2088 	int ret;
2089 
2090 	if (!rdma_frwr_is_supported(&new_cm_id->device->attrs)) {
2091 		ksmbd_debug(RDMA,
2092 			    "Fast Registration Work Requests is not supported. device capabilities=%llx\n",
2093 			    new_cm_id->device->attrs.device_cap_flags);
2094 		return -EPROTONOSUPPORT;
2095 	}
2096 
2097 	t = alloc_transport(new_cm_id);
2098 	if (!t)
2099 		return -ENOMEM;
2100 
2101 	ret = smb_direct_connect(t);
2102 	if (ret)
2103 		goto out_err;
2104 
2105 	handler = kthread_run(ksmbd_conn_handler_loop,
2106 			      KSMBD_TRANS(t)->conn, "ksmbd:r%u",
2107 			      smb_direct_port);
2108 	if (IS_ERR(handler)) {
2109 		ret = PTR_ERR(handler);
2110 		pr_err("Can't start thread\n");
2111 		goto out_err;
2112 	}
2113 
2114 	return 0;
2115 out_err:
2116 	free_transport(t);
2117 	return ret;
2118 }
2119 
2120 static int smb_direct_listen_handler(struct rdma_cm_id *cm_id,
2121 				     struct rdma_cm_event *event)
2122 {
2123 	switch (event->event) {
2124 	case RDMA_CM_EVENT_CONNECT_REQUEST: {
2125 		int ret = smb_direct_handle_connect_request(cm_id);
2126 
2127 		if (ret) {
2128 			pr_err("Can't create transport: %d\n", ret);
2129 			return ret;
2130 		}
2131 
2132 		ksmbd_debug(RDMA, "Received connection request. cm_id=%p\n",
2133 			    cm_id);
2134 		break;
2135 	}
2136 	default:
2137 		pr_err("Unexpected listen event. cm_id=%p, event=%s (%d)\n",
2138 		       cm_id, rdma_event_msg(event->event), event->event);
2139 		break;
2140 	}
2141 	return 0;
2142 }
2143 
2144 static int smb_direct_listen(int port)
2145 {
2146 	int ret;
2147 	struct rdma_cm_id *cm_id;
2148 	struct sockaddr_in sin = {
2149 		.sin_family		= AF_INET,
2150 		.sin_addr.s_addr	= htonl(INADDR_ANY),
2151 		.sin_port		= htons(port),
2152 	};
2153 
2154 	cm_id = rdma_create_id(&init_net, smb_direct_listen_handler,
2155 			       &smb_direct_listener, RDMA_PS_TCP, IB_QPT_RC);
2156 	if (IS_ERR(cm_id)) {
2157 		pr_err("Can't create cm id: %ld\n", PTR_ERR(cm_id));
2158 		return PTR_ERR(cm_id);
2159 	}
2160 
2161 	ret = rdma_bind_addr(cm_id, (struct sockaddr *)&sin);
2162 	if (ret) {
2163 		pr_err("Can't bind: %d\n", ret);
2164 		goto err;
2165 	}
2166 
2167 	smb_direct_listener.cm_id = cm_id;
2168 
2169 	ret = rdma_listen(cm_id, 10);
2170 	if (ret) {
2171 		pr_err("Can't listen: %d\n", ret);
2172 		goto err;
2173 	}
2174 	return 0;
2175 err:
2176 	smb_direct_listener.cm_id = NULL;
2177 	rdma_destroy_id(cm_id);
2178 	return ret;
2179 }
2180 
2181 static int smb_direct_ib_client_add(struct ib_device *ib_dev)
2182 {
2183 	struct smb_direct_device *smb_dev;
2184 
2185 	/* Set 5445 port if device type is iWARP(No IB) */
2186 	if (ib_dev->node_type != RDMA_NODE_IB_CA)
2187 		smb_direct_port = SMB_DIRECT_PORT_IWARP;
2188 
2189 	if (!rdma_frwr_is_supported(&ib_dev->attrs))
2190 		return 0;
2191 
2192 	smb_dev = kzalloc(sizeof(*smb_dev), KSMBD_DEFAULT_GFP);
2193 	if (!smb_dev)
2194 		return -ENOMEM;
2195 	smb_dev->ib_dev = ib_dev;
2196 
2197 	write_lock(&smb_direct_device_lock);
2198 	list_add(&smb_dev->list, &smb_direct_device_list);
2199 	write_unlock(&smb_direct_device_lock);
2200 
2201 	ksmbd_debug(RDMA, "ib device added: name %s\n", ib_dev->name);
2202 	return 0;
2203 }
2204 
2205 static void smb_direct_ib_client_remove(struct ib_device *ib_dev,
2206 					void *client_data)
2207 {
2208 	struct smb_direct_device *smb_dev, *tmp;
2209 
2210 	write_lock(&smb_direct_device_lock);
2211 	list_for_each_entry_safe(smb_dev, tmp, &smb_direct_device_list, list) {
2212 		if (smb_dev->ib_dev == ib_dev) {
2213 			list_del(&smb_dev->list);
2214 			kfree(smb_dev);
2215 			break;
2216 		}
2217 	}
2218 	write_unlock(&smb_direct_device_lock);
2219 }
2220 
2221 static struct ib_client smb_direct_ib_client = {
2222 	.name	= "ksmbd_smb_direct_ib",
2223 	.add	= smb_direct_ib_client_add,
2224 	.remove	= smb_direct_ib_client_remove,
2225 };
2226 
2227 int ksmbd_rdma_init(void)
2228 {
2229 	int ret;
2230 
2231 	smb_direct_listener.cm_id = NULL;
2232 
2233 	ret = ib_register_client(&smb_direct_ib_client);
2234 	if (ret) {
2235 		pr_err("failed to ib_register_client\n");
2236 		return ret;
2237 	}
2238 
2239 	/* When a client is running out of send credits, the credits are
2240 	 * granted by the server's sending a packet using this queue.
2241 	 * This avoids the situation that a clients cannot send packets
2242 	 * for lack of credits
2243 	 */
2244 	smb_direct_wq = alloc_workqueue("ksmbd-smb_direct-wq",
2245 					WQ_HIGHPRI | WQ_MEM_RECLAIM, 0);
2246 	if (!smb_direct_wq)
2247 		return -ENOMEM;
2248 
2249 	ret = smb_direct_listen(smb_direct_port);
2250 	if (ret) {
2251 		destroy_workqueue(smb_direct_wq);
2252 		smb_direct_wq = NULL;
2253 		pr_err("Can't listen: %d\n", ret);
2254 		return ret;
2255 	}
2256 
2257 	ksmbd_debug(RDMA, "init RDMA listener. cm_id=%p\n",
2258 		    smb_direct_listener.cm_id);
2259 	return 0;
2260 }
2261 
2262 void ksmbd_rdma_stop_listening(void)
2263 {
2264 	if (!smb_direct_listener.cm_id)
2265 		return;
2266 
2267 	ib_unregister_client(&smb_direct_ib_client);
2268 	rdma_destroy_id(smb_direct_listener.cm_id);
2269 
2270 	smb_direct_listener.cm_id = NULL;
2271 }
2272 
2273 void ksmbd_rdma_destroy(void)
2274 {
2275 	if (smb_direct_wq) {
2276 		destroy_workqueue(smb_direct_wq);
2277 		smb_direct_wq = NULL;
2278 	}
2279 }
2280 
2281 bool ksmbd_rdma_capable_netdev(struct net_device *netdev)
2282 {
2283 	struct smb_direct_device *smb_dev;
2284 	int i;
2285 	bool rdma_capable = false;
2286 
2287 	read_lock(&smb_direct_device_lock);
2288 	list_for_each_entry(smb_dev, &smb_direct_device_list, list) {
2289 		for (i = 0; i < smb_dev->ib_dev->phys_port_cnt; i++) {
2290 			struct net_device *ndev;
2291 
2292 			ndev = ib_device_get_netdev(smb_dev->ib_dev, i + 1);
2293 			if (!ndev)
2294 				continue;
2295 
2296 			if (ndev == netdev) {
2297 				dev_put(ndev);
2298 				rdma_capable = true;
2299 				goto out;
2300 			}
2301 			dev_put(ndev);
2302 		}
2303 	}
2304 out:
2305 	read_unlock(&smb_direct_device_lock);
2306 
2307 	if (rdma_capable == false) {
2308 		struct ib_device *ibdev;
2309 
2310 		ibdev = ib_device_get_by_netdev(netdev, RDMA_DRIVER_UNKNOWN);
2311 		if (ibdev) {
2312 			rdma_capable = rdma_frwr_is_supported(&ibdev->attrs);
2313 			ib_device_put(ibdev);
2314 		}
2315 	}
2316 
2317 	ksmbd_debug(RDMA, "netdev(%s) rdma capable : %s\n",
2318 		    netdev->name, str_true_false(rdma_capable));
2319 
2320 	return rdma_capable;
2321 }
2322 
2323 static const struct ksmbd_transport_ops ksmbd_smb_direct_transport_ops = {
2324 	.prepare	= smb_direct_prepare,
2325 	.disconnect	= smb_direct_disconnect,
2326 	.shutdown	= smb_direct_shutdown,
2327 	.writev		= smb_direct_writev,
2328 	.read		= smb_direct_read,
2329 	.rdma_read	= smb_direct_rdma_read,
2330 	.rdma_write	= smb_direct_rdma_write,
2331 	.free_transport = smb_direct_free_transport,
2332 };
2333