1 /*
2  * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. All rights reserved.
3  * Copyright (c) 2013 Mellanox Technologies. All rights reserved.
4  *
5  * This software is available to you under a choice of one of two
6  * licenses.  You may choose to be licensed under the terms of the GNU
7  * General Public License (GPL) Version 2, available from the file
8  * COPYING in the main directory of this source tree, or the
9  * OpenIB.org BSD license below:
10  *
11  *     Redistribution and use in source and binary forms, with or
12  *     without modification, are permitted provided that the following
13  *     conditions are met:
14  *
15  *	- Redistributions of source code must retain the above
16  *	  copyright notice, this list of conditions and the following
17  *	  disclaimer.
18  *
19  *	- Redistributions in binary form must reproduce the above
20  *	  copyright notice, this list of conditions and the following
21  *	  disclaimer in the documentation and/or other materials
22  *	  provided with the distribution.
23  *
24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
25  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
26  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
27  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
28  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
29  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
30  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
31  * SOFTWARE.
32  */
33 #include <linux/kernel.h>
34 #include <linux/slab.h>
35 #include <linux/mm.h>
36 #include <linux/scatterlist.h>
37 #include <linux/kfifo.h>
38 #include <scsi/scsi_cmnd.h>
39 #include <scsi/scsi_host.h>
40 
41 #include "iscsi_iser.h"
42 
43 /* Register user buffer memory and initialize passive rdma
44  *  dto descriptor. Total data size is stored in
45  *  iser_task->data[ISER_DIR_IN].data_len
46  */
47 static int iser_prepare_read_cmd(struct iscsi_task *task,
48 				 unsigned int edtl)
49 
50 {
51 	struct iscsi_iser_task *iser_task = task->dd_data;
52 	struct iser_device  *device = iser_task->iser_conn->ib_conn->device;
53 	struct iser_regd_buf *regd_buf;
54 	int err;
55 	struct iser_hdr *hdr = &iser_task->desc.iser_header;
56 	struct iser_data_buf *buf_in = &iser_task->data[ISER_DIR_IN];
57 
58 	err = iser_dma_map_task_data(iser_task,
59 				     buf_in,
60 				     ISER_DIR_IN,
61 				     DMA_FROM_DEVICE);
62 	if (err)
63 		return err;
64 
65 	if (edtl > iser_task->data[ISER_DIR_IN].data_len) {
66 		iser_err("Total data length: %ld, less than EDTL: "
67 			 "%d, in READ cmd BHS itt: %d, conn: 0x%p\n",
68 			 iser_task->data[ISER_DIR_IN].data_len, edtl,
69 			 task->itt, iser_task->iser_conn);
70 		return -EINVAL;
71 	}
72 
73 	err = device->iser_reg_rdma_mem(iser_task, ISER_DIR_IN);
74 	if (err) {
75 		iser_err("Failed to set up Data-IN RDMA\n");
76 		return err;
77 	}
78 	regd_buf = &iser_task->rdma_regd[ISER_DIR_IN];
79 
80 	hdr->flags    |= ISER_RSV;
81 	hdr->read_stag = cpu_to_be32(regd_buf->reg.rkey);
82 	hdr->read_va   = cpu_to_be64(regd_buf->reg.va);
83 
84 	iser_dbg("Cmd itt:%d READ tags RKEY:%#.4X VA:%#llX\n",
85 		 task->itt, regd_buf->reg.rkey,
86 		 (unsigned long long)regd_buf->reg.va);
87 
88 	return 0;
89 }
90 
91 /* Register user buffer memory and initialize passive rdma
92  *  dto descriptor. Total data size is stored in
93  *  task->data[ISER_DIR_OUT].data_len
94  */
95 static int
96 iser_prepare_write_cmd(struct iscsi_task *task,
97 		       unsigned int imm_sz,
98 		       unsigned int unsol_sz,
99 		       unsigned int edtl)
100 {
101 	struct iscsi_iser_task *iser_task = task->dd_data;
102 	struct iser_device  *device = iser_task->iser_conn->ib_conn->device;
103 	struct iser_regd_buf *regd_buf;
104 	int err;
105 	struct iser_hdr *hdr = &iser_task->desc.iser_header;
106 	struct iser_data_buf *buf_out = &iser_task->data[ISER_DIR_OUT];
107 	struct ib_sge *tx_dsg = &iser_task->desc.tx_sg[1];
108 
109 	err = iser_dma_map_task_data(iser_task,
110 				     buf_out,
111 				     ISER_DIR_OUT,
112 				     DMA_TO_DEVICE);
113 	if (err)
114 		return err;
115 
116 	if (edtl > iser_task->data[ISER_DIR_OUT].data_len) {
117 		iser_err("Total data length: %ld, less than EDTL: %d, "
118 			 "in WRITE cmd BHS itt: %d, conn: 0x%p\n",
119 			 iser_task->data[ISER_DIR_OUT].data_len,
120 			 edtl, task->itt, task->conn);
121 		return -EINVAL;
122 	}
123 
124 	err = device->iser_reg_rdma_mem(iser_task, ISER_DIR_OUT);
125 	if (err != 0) {
126 		iser_err("Failed to register write cmd RDMA mem\n");
127 		return err;
128 	}
129 
130 	regd_buf = &iser_task->rdma_regd[ISER_DIR_OUT];
131 
132 	if (unsol_sz < edtl) {
133 		hdr->flags     |= ISER_WSV;
134 		hdr->write_stag = cpu_to_be32(regd_buf->reg.rkey);
135 		hdr->write_va   = cpu_to_be64(regd_buf->reg.va + unsol_sz);
136 
137 		iser_dbg("Cmd itt:%d, WRITE tags, RKEY:%#.4X "
138 			 "VA:%#llX + unsol:%d\n",
139 			 task->itt, regd_buf->reg.rkey,
140 			 (unsigned long long)regd_buf->reg.va, unsol_sz);
141 	}
142 
143 	if (imm_sz > 0) {
144 		iser_dbg("Cmd itt:%d, WRITE, adding imm.data sz: %d\n",
145 			 task->itt, imm_sz);
146 		tx_dsg->addr   = regd_buf->reg.va;
147 		tx_dsg->length = imm_sz;
148 		tx_dsg->lkey   = regd_buf->reg.lkey;
149 		iser_task->desc.num_sge = 2;
150 	}
151 
152 	return 0;
153 }
154 
155 /* creates a new tx descriptor and adds header regd buffer */
156 static void iser_create_send_desc(struct iser_conn	*ib_conn,
157 				  struct iser_tx_desc	*tx_desc)
158 {
159 	struct iser_device *device = ib_conn->device;
160 
161 	ib_dma_sync_single_for_cpu(device->ib_device,
162 		tx_desc->dma_addr, ISER_HEADERS_LEN, DMA_TO_DEVICE);
163 
164 	memset(&tx_desc->iser_header, 0, sizeof(struct iser_hdr));
165 	tx_desc->iser_header.flags = ISER_VER;
166 
167 	tx_desc->num_sge = 1;
168 
169 	if (tx_desc->tx_sg[0].lkey != device->mr->lkey) {
170 		tx_desc->tx_sg[0].lkey = device->mr->lkey;
171 		iser_dbg("sdesc %p lkey mismatch, fixing\n", tx_desc);
172 	}
173 }
174 
175 static void iser_free_login_buf(struct iser_conn *ib_conn)
176 {
177 	if (!ib_conn->login_buf)
178 		return;
179 
180 	if (ib_conn->login_req_dma)
181 		ib_dma_unmap_single(ib_conn->device->ib_device,
182 				    ib_conn->login_req_dma,
183 				    ISCSI_DEF_MAX_RECV_SEG_LEN, DMA_TO_DEVICE);
184 
185 	if (ib_conn->login_resp_dma)
186 		ib_dma_unmap_single(ib_conn->device->ib_device,
187 				    ib_conn->login_resp_dma,
188 				    ISER_RX_LOGIN_SIZE, DMA_FROM_DEVICE);
189 
190 	kfree(ib_conn->login_buf);
191 
192 	/* make sure we never redo any unmapping */
193 	ib_conn->login_req_dma = 0;
194 	ib_conn->login_resp_dma = 0;
195 	ib_conn->login_buf = NULL;
196 }
197 
198 static int iser_alloc_login_buf(struct iser_conn *ib_conn)
199 {
200 	struct iser_device	*device;
201 	int			req_err, resp_err;
202 
203 	BUG_ON(ib_conn->device == NULL);
204 
205 	device = ib_conn->device;
206 
207 	ib_conn->login_buf = kmalloc(ISCSI_DEF_MAX_RECV_SEG_LEN +
208 				     ISER_RX_LOGIN_SIZE, GFP_KERNEL);
209 	if (!ib_conn->login_buf)
210 		goto out_err;
211 
212 	ib_conn->login_req_buf  = ib_conn->login_buf;
213 	ib_conn->login_resp_buf = ib_conn->login_buf +
214 						ISCSI_DEF_MAX_RECV_SEG_LEN;
215 
216 	ib_conn->login_req_dma = ib_dma_map_single(ib_conn->device->ib_device,
217 				(void *)ib_conn->login_req_buf,
218 				ISCSI_DEF_MAX_RECV_SEG_LEN, DMA_TO_DEVICE);
219 
220 	ib_conn->login_resp_dma = ib_dma_map_single(ib_conn->device->ib_device,
221 				(void *)ib_conn->login_resp_buf,
222 				ISER_RX_LOGIN_SIZE, DMA_FROM_DEVICE);
223 
224 	req_err  = ib_dma_mapping_error(device->ib_device,
225 					ib_conn->login_req_dma);
226 	resp_err = ib_dma_mapping_error(device->ib_device,
227 					ib_conn->login_resp_dma);
228 
229 	if (req_err || resp_err) {
230 		if (req_err)
231 			ib_conn->login_req_dma = 0;
232 		if (resp_err)
233 			ib_conn->login_resp_dma = 0;
234 		goto free_login_buf;
235 	}
236 	return 0;
237 
238 free_login_buf:
239 	iser_free_login_buf(ib_conn);
240 
241 out_err:
242 	iser_err("unable to alloc or map login buf\n");
243 	return -ENOMEM;
244 }
245 
246 int iser_alloc_rx_descriptors(struct iser_conn *ib_conn, struct iscsi_session *session)
247 {
248 	int i, j;
249 	u64 dma_addr;
250 	struct iser_rx_desc *rx_desc;
251 	struct ib_sge       *rx_sg;
252 	struct iser_device  *device = ib_conn->device;
253 
254 	ib_conn->qp_max_recv_dtos = session->cmds_max;
255 	ib_conn->qp_max_recv_dtos_mask = session->cmds_max - 1; /* cmds_max is 2^N */
256 	ib_conn->min_posted_rx = ib_conn->qp_max_recv_dtos >> 2;
257 
258 	if (device->iser_alloc_rdma_reg_res(ib_conn, session->scsi_cmds_max))
259 		goto create_rdma_reg_res_failed;
260 
261 	if (iser_alloc_login_buf(ib_conn))
262 		goto alloc_login_buf_fail;
263 
264 	ib_conn->rx_descs = kmalloc(session->cmds_max *
265 				sizeof(struct iser_rx_desc), GFP_KERNEL);
266 	if (!ib_conn->rx_descs)
267 		goto rx_desc_alloc_fail;
268 
269 	rx_desc = ib_conn->rx_descs;
270 
271 	for (i = 0; i < ib_conn->qp_max_recv_dtos; i++, rx_desc++)  {
272 		dma_addr = ib_dma_map_single(device->ib_device, (void *)rx_desc,
273 					ISER_RX_PAYLOAD_SIZE, DMA_FROM_DEVICE);
274 		if (ib_dma_mapping_error(device->ib_device, dma_addr))
275 			goto rx_desc_dma_map_failed;
276 
277 		rx_desc->dma_addr = dma_addr;
278 
279 		rx_sg = &rx_desc->rx_sg;
280 		rx_sg->addr   = rx_desc->dma_addr;
281 		rx_sg->length = ISER_RX_PAYLOAD_SIZE;
282 		rx_sg->lkey   = device->mr->lkey;
283 	}
284 
285 	ib_conn->rx_desc_head = 0;
286 	return 0;
287 
288 rx_desc_dma_map_failed:
289 	rx_desc = ib_conn->rx_descs;
290 	for (j = 0; j < i; j++, rx_desc++)
291 		ib_dma_unmap_single(device->ib_device, rx_desc->dma_addr,
292 				    ISER_RX_PAYLOAD_SIZE, DMA_FROM_DEVICE);
293 	kfree(ib_conn->rx_descs);
294 	ib_conn->rx_descs = NULL;
295 rx_desc_alloc_fail:
296 	iser_free_login_buf(ib_conn);
297 alloc_login_buf_fail:
298 	device->iser_free_rdma_reg_res(ib_conn);
299 create_rdma_reg_res_failed:
300 	iser_err("failed allocating rx descriptors / data buffers\n");
301 	return -ENOMEM;
302 }
303 
304 void iser_free_rx_descriptors(struct iser_conn *ib_conn)
305 {
306 	int i;
307 	struct iser_rx_desc *rx_desc;
308 	struct iser_device *device = ib_conn->device;
309 
310 	if (!ib_conn->rx_descs)
311 		goto free_login_buf;
312 
313 	if (device->iser_free_rdma_reg_res)
314 		device->iser_free_rdma_reg_res(ib_conn);
315 
316 	rx_desc = ib_conn->rx_descs;
317 	for (i = 0; i < ib_conn->qp_max_recv_dtos; i++, rx_desc++)
318 		ib_dma_unmap_single(device->ib_device, rx_desc->dma_addr,
319 				    ISER_RX_PAYLOAD_SIZE, DMA_FROM_DEVICE);
320 	kfree(ib_conn->rx_descs);
321 	/* make sure we never redo any unmapping */
322 	ib_conn->rx_descs = NULL;
323 
324 free_login_buf:
325 	iser_free_login_buf(ib_conn);
326 }
327 
328 static int iser_post_rx_bufs(struct iscsi_conn *conn, struct iscsi_hdr *req)
329 {
330 	struct iscsi_iser_conn *iser_conn = conn->dd_data;
331 	struct iscsi_session *session = conn->session;
332 
333 	iser_dbg("req op %x flags %x\n", req->opcode, req->flags);
334 	/* check if this is the last login - going to full feature phase */
335 	if ((req->flags & ISCSI_FULL_FEATURE_PHASE) != ISCSI_FULL_FEATURE_PHASE)
336 		return 0;
337 
338 	/*
339 	 * Check that there is one posted recv buffer (for the last login
340 	 * response) and no posted send buffers left - they must have been
341 	 * consumed during previous login phases.
342 	 */
343 	WARN_ON(iser_conn->ib_conn->post_recv_buf_count != 1);
344 	WARN_ON(atomic_read(&iser_conn->ib_conn->post_send_buf_count) != 0);
345 
346 	if (session->discovery_sess) {
347 		iser_info("Discovery session, re-using login RX buffer\n");
348 		return 0;
349 	} else
350 		iser_info("Normal session, posting batch of RX %d buffers\n",
351 			  iser_conn->ib_conn->min_posted_rx);
352 
353 	/* Initial post receive buffers */
354 	if (iser_post_recvm(iser_conn->ib_conn,
355 			    iser_conn->ib_conn->min_posted_rx))
356 		return -ENOMEM;
357 
358 	return 0;
359 }
360 
361 /**
362  * iser_send_command - send command PDU
363  */
364 int iser_send_command(struct iscsi_conn *conn,
365 		      struct iscsi_task *task)
366 {
367 	struct iscsi_iser_conn *iser_conn = conn->dd_data;
368 	struct iscsi_iser_task *iser_task = task->dd_data;
369 	unsigned long edtl;
370 	int err;
371 	struct iser_data_buf *data_buf;
372 	struct iscsi_scsi_req *hdr = (struct iscsi_scsi_req *)task->hdr;
373 	struct scsi_cmnd *sc  =  task->sc;
374 	struct iser_tx_desc *tx_desc = &iser_task->desc;
375 
376 	edtl = ntohl(hdr->data_length);
377 
378 	/* build the tx desc regd header and add it to the tx desc dto */
379 	tx_desc->type = ISCSI_TX_SCSI_COMMAND;
380 	iser_create_send_desc(iser_conn->ib_conn, tx_desc);
381 
382 	if (hdr->flags & ISCSI_FLAG_CMD_READ)
383 		data_buf = &iser_task->data[ISER_DIR_IN];
384 	else
385 		data_buf = &iser_task->data[ISER_DIR_OUT];
386 
387 	if (scsi_sg_count(sc)) { /* using a scatter list */
388 		data_buf->buf  = scsi_sglist(sc);
389 		data_buf->size = scsi_sg_count(sc);
390 	}
391 
392 	data_buf->data_len = scsi_bufflen(sc);
393 
394 	if (hdr->flags & ISCSI_FLAG_CMD_READ) {
395 		err = iser_prepare_read_cmd(task, edtl);
396 		if (err)
397 			goto send_command_error;
398 	}
399 	if (hdr->flags & ISCSI_FLAG_CMD_WRITE) {
400 		err = iser_prepare_write_cmd(task,
401 					     task->imm_count,
402 				             task->imm_count +
403 					     task->unsol_r2t.data_length,
404 					     edtl);
405 		if (err)
406 			goto send_command_error;
407 	}
408 
409 	iser_task->status = ISER_TASK_STATUS_STARTED;
410 
411 	err = iser_post_send(iser_conn->ib_conn, tx_desc);
412 	if (!err)
413 		return 0;
414 
415 send_command_error:
416 	iser_err("conn %p failed task->itt %d err %d\n",conn, task->itt, err);
417 	return err;
418 }
419 
420 /**
421  * iser_send_data_out - send data out PDU
422  */
423 int iser_send_data_out(struct iscsi_conn *conn,
424 		       struct iscsi_task *task,
425 		       struct iscsi_data *hdr)
426 {
427 	struct iscsi_iser_conn *iser_conn = conn->dd_data;
428 	struct iscsi_iser_task *iser_task = task->dd_data;
429 	struct iser_tx_desc *tx_desc = NULL;
430 	struct iser_regd_buf *regd_buf;
431 	unsigned long buf_offset;
432 	unsigned long data_seg_len;
433 	uint32_t itt;
434 	int err = 0;
435 	struct ib_sge *tx_dsg;
436 
437 	itt = (__force uint32_t)hdr->itt;
438 	data_seg_len = ntoh24(hdr->dlength);
439 	buf_offset   = ntohl(hdr->offset);
440 
441 	iser_dbg("%s itt %d dseg_len %d offset %d\n",
442 		 __func__,(int)itt,(int)data_seg_len,(int)buf_offset);
443 
444 	tx_desc = kmem_cache_zalloc(ig.desc_cache, GFP_ATOMIC);
445 	if (tx_desc == NULL) {
446 		iser_err("Failed to alloc desc for post dataout\n");
447 		return -ENOMEM;
448 	}
449 
450 	tx_desc->type = ISCSI_TX_DATAOUT;
451 	tx_desc->iser_header.flags = ISER_VER;
452 	memcpy(&tx_desc->iscsi_header, hdr, sizeof(struct iscsi_hdr));
453 
454 	/* build the tx desc */
455 	iser_initialize_task_headers(task, tx_desc);
456 
457 	regd_buf = &iser_task->rdma_regd[ISER_DIR_OUT];
458 	tx_dsg = &tx_desc->tx_sg[1];
459 	tx_dsg->addr    = regd_buf->reg.va + buf_offset;
460 	tx_dsg->length  = data_seg_len;
461 	tx_dsg->lkey    = regd_buf->reg.lkey;
462 	tx_desc->num_sge = 2;
463 
464 	if (buf_offset + data_seg_len > iser_task->data[ISER_DIR_OUT].data_len) {
465 		iser_err("Offset:%ld & DSL:%ld in Data-Out "
466 			 "inconsistent with total len:%ld, itt:%d\n",
467 			 buf_offset, data_seg_len,
468 			 iser_task->data[ISER_DIR_OUT].data_len, itt);
469 		err = -EINVAL;
470 		goto send_data_out_error;
471 	}
472 	iser_dbg("data-out itt: %d, offset: %ld, sz: %ld\n",
473 		 itt, buf_offset, data_seg_len);
474 
475 
476 	err = iser_post_send(iser_conn->ib_conn, tx_desc);
477 	if (!err)
478 		return 0;
479 
480 send_data_out_error:
481 	kmem_cache_free(ig.desc_cache, tx_desc);
482 	iser_err("conn %p failed err %d\n",conn, err);
483 	return err;
484 }
485 
486 int iser_send_control(struct iscsi_conn *conn,
487 		      struct iscsi_task *task)
488 {
489 	struct iscsi_iser_conn *iser_conn = conn->dd_data;
490 	struct iscsi_iser_task *iser_task = task->dd_data;
491 	struct iser_tx_desc *mdesc = &iser_task->desc;
492 	unsigned long data_seg_len;
493 	int err = 0;
494 	struct iser_device *device;
495 	struct iser_conn *ib_conn = iser_conn->ib_conn;
496 
497 	/* build the tx desc regd header and add it to the tx desc dto */
498 	mdesc->type = ISCSI_TX_CONTROL;
499 	iser_create_send_desc(iser_conn->ib_conn, mdesc);
500 
501 	device = iser_conn->ib_conn->device;
502 
503 	data_seg_len = ntoh24(task->hdr->dlength);
504 
505 	if (data_seg_len > 0) {
506 		struct ib_sge *tx_dsg = &mdesc->tx_sg[1];
507 		if (task != conn->login_task) {
508 			iser_err("data present on non login task!!!\n");
509 			goto send_control_error;
510 		}
511 
512 		ib_dma_sync_single_for_cpu(device->ib_device,
513 			ib_conn->login_req_dma, task->data_count,
514 			DMA_TO_DEVICE);
515 
516 		memcpy(iser_conn->ib_conn->login_req_buf, task->data,
517 							task->data_count);
518 
519 		ib_dma_sync_single_for_device(device->ib_device,
520 			ib_conn->login_req_dma, task->data_count,
521 			DMA_TO_DEVICE);
522 
523 		tx_dsg->addr    = iser_conn->ib_conn->login_req_dma;
524 		tx_dsg->length  = task->data_count;
525 		tx_dsg->lkey    = device->mr->lkey;
526 		mdesc->num_sge = 2;
527 	}
528 
529 	if (task == conn->login_task) {
530 		iser_dbg("op %x dsl %lx, posting login rx buffer\n",
531 			 task->hdr->opcode, data_seg_len);
532 		err = iser_post_recvl(iser_conn->ib_conn);
533 		if (err)
534 			goto send_control_error;
535 		err = iser_post_rx_bufs(conn, task->hdr);
536 		if (err)
537 			goto send_control_error;
538 	}
539 
540 	err = iser_post_send(iser_conn->ib_conn, mdesc);
541 	if (!err)
542 		return 0;
543 
544 send_control_error:
545 	iser_err("conn %p failed err %d\n",conn, err);
546 	return err;
547 }
548 
549 /**
550  * iser_rcv_dto_completion - recv DTO completion
551  */
552 void iser_rcv_completion(struct iser_rx_desc *rx_desc,
553 			 unsigned long rx_xfer_len,
554 			 struct iser_conn *ib_conn)
555 {
556 	struct iscsi_iser_conn *conn = ib_conn->iser_conn;
557 	struct iscsi_hdr *hdr;
558 	u64 rx_dma;
559 	int rx_buflen, outstanding, count, err;
560 
561 	/* differentiate between login to all other PDUs */
562 	if ((char *)rx_desc == ib_conn->login_resp_buf) {
563 		rx_dma = ib_conn->login_resp_dma;
564 		rx_buflen = ISER_RX_LOGIN_SIZE;
565 	} else {
566 		rx_dma = rx_desc->dma_addr;
567 		rx_buflen = ISER_RX_PAYLOAD_SIZE;
568 	}
569 
570 	ib_dma_sync_single_for_cpu(ib_conn->device->ib_device, rx_dma,
571 			rx_buflen, DMA_FROM_DEVICE);
572 
573 	hdr = &rx_desc->iscsi_header;
574 
575 	iser_dbg("op 0x%x itt 0x%x dlen %d\n", hdr->opcode,
576 			hdr->itt, (int)(rx_xfer_len - ISER_HEADERS_LEN));
577 
578 	iscsi_iser_recv(conn->iscsi_conn, hdr,
579 		rx_desc->data, rx_xfer_len - ISER_HEADERS_LEN);
580 
581 	ib_dma_sync_single_for_device(ib_conn->device->ib_device, rx_dma,
582 			rx_buflen, DMA_FROM_DEVICE);
583 
584 	/* decrementing conn->post_recv_buf_count only --after-- freeing the   *
585 	 * task eliminates the need to worry on tasks which are completed in   *
586 	 * parallel to the execution of iser_conn_term. So the code that waits *
587 	 * for the posted rx bufs refcount to become zero handles everything   */
588 	conn->ib_conn->post_recv_buf_count--;
589 
590 	if (rx_dma == ib_conn->login_resp_dma)
591 		return;
592 
593 	outstanding = ib_conn->post_recv_buf_count;
594 	if (outstanding + ib_conn->min_posted_rx <= ib_conn->qp_max_recv_dtos) {
595 		count = min(ib_conn->qp_max_recv_dtos - outstanding,
596 						ib_conn->min_posted_rx);
597 		err = iser_post_recvm(ib_conn, count);
598 		if (err)
599 			iser_err("posting %d rx bufs err %d\n", count, err);
600 	}
601 }
602 
603 void iser_snd_completion(struct iser_tx_desc *tx_desc,
604 			struct iser_conn *ib_conn)
605 {
606 	struct iscsi_task *task;
607 	struct iser_device *device = ib_conn->device;
608 
609 	if (tx_desc->type == ISCSI_TX_DATAOUT) {
610 		ib_dma_unmap_single(device->ib_device, tx_desc->dma_addr,
611 					ISER_HEADERS_LEN, DMA_TO_DEVICE);
612 		kmem_cache_free(ig.desc_cache, tx_desc);
613 		tx_desc = NULL;
614 	}
615 
616 	atomic_dec(&ib_conn->post_send_buf_count);
617 
618 	if (tx_desc && tx_desc->type == ISCSI_TX_CONTROL) {
619 		/* this arithmetic is legal by libiscsi dd_data allocation */
620 		task = (void *) ((long)(void *)tx_desc -
621 				  sizeof(struct iscsi_task));
622 		if (task->hdr->itt == RESERVED_ITT)
623 			iscsi_put_task(task);
624 	}
625 }
626 
627 void iser_task_rdma_init(struct iscsi_iser_task *iser_task)
628 
629 {
630 	iser_task->status = ISER_TASK_STATUS_INIT;
631 
632 	iser_task->dir[ISER_DIR_IN] = 0;
633 	iser_task->dir[ISER_DIR_OUT] = 0;
634 
635 	iser_task->data[ISER_DIR_IN].data_len  = 0;
636 	iser_task->data[ISER_DIR_OUT].data_len = 0;
637 
638 	memset(&iser_task->rdma_regd[ISER_DIR_IN], 0,
639 	       sizeof(struct iser_regd_buf));
640 	memset(&iser_task->rdma_regd[ISER_DIR_OUT], 0,
641 	       sizeof(struct iser_regd_buf));
642 }
643 
644 void iser_task_rdma_finalize(struct iscsi_iser_task *iser_task)
645 {
646 	struct iser_device *device = iser_task->iser_conn->ib_conn->device;
647 	int is_rdma_aligned = 1;
648 
649 	/* if we were reading, copy back to unaligned sglist,
650 	 * anyway dma_unmap and free the copy
651 	 */
652 	if (iser_task->data_copy[ISER_DIR_IN].copy_buf != NULL) {
653 		is_rdma_aligned = 0;
654 		iser_finalize_rdma_unaligned_sg(iser_task, ISER_DIR_IN);
655 	}
656 	if (iser_task->data_copy[ISER_DIR_OUT].copy_buf != NULL) {
657 		is_rdma_aligned = 0;
658 		iser_finalize_rdma_unaligned_sg(iser_task, ISER_DIR_OUT);
659 	}
660 
661 	if (iser_task->dir[ISER_DIR_IN])
662 		device->iser_unreg_rdma_mem(iser_task, ISER_DIR_IN);
663 
664 	if (iser_task->dir[ISER_DIR_OUT])
665 		device->iser_unreg_rdma_mem(iser_task, ISER_DIR_OUT);
666 
667        /* if the data was unaligned, it was already unmapped and then copied */
668        if (is_rdma_aligned)
669 		iser_dma_unmap_task_data(iser_task);
670 }
671