xref: /linux/drivers/infiniband/ulp/iser/iser_initiator.c (revision 93d90ad708b8da6efc0e487b66111aa9db7f70c7)
1 /*
2  * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. All rights reserved.
3  * Copyright (c) 2013-2014 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. Data size is stored in
45  *  task->data[ISER_DIR_IN].data_len, Protection size
46  *  os stored in task->prot[ISER_DIR_IN].data_len
47  */
48 static int iser_prepare_read_cmd(struct iscsi_task *task)
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 (scsi_prot_sg_count(iser_task->sc)) {
66 		struct iser_data_buf *pbuf_in = &iser_task->prot[ISER_DIR_IN];
67 
68 		err = iser_dma_map_task_data(iser_task,
69 					     pbuf_in,
70 					     ISER_DIR_IN,
71 					     DMA_FROM_DEVICE);
72 		if (err)
73 			return err;
74 	}
75 
76 	err = device->iser_reg_rdma_mem(iser_task, ISER_DIR_IN);
77 	if (err) {
78 		iser_err("Failed to set up Data-IN RDMA\n");
79 		return err;
80 	}
81 	regd_buf = &iser_task->rdma_regd[ISER_DIR_IN];
82 
83 	hdr->flags    |= ISER_RSV;
84 	hdr->read_stag = cpu_to_be32(regd_buf->reg.rkey);
85 	hdr->read_va   = cpu_to_be64(regd_buf->reg.va);
86 
87 	iser_dbg("Cmd itt:%d READ tags RKEY:%#.4X VA:%#llX\n",
88 		 task->itt, regd_buf->reg.rkey,
89 		 (unsigned long long)regd_buf->reg.va);
90 
91 	return 0;
92 }
93 
94 /* Register user buffer memory and initialize passive rdma
95  *  dto descriptor. Data size is stored in
96  *  task->data[ISER_DIR_OUT].data_len, Protection size
97  *  is stored at task->prot[ISER_DIR_OUT].data_len
98  */
99 static int
100 iser_prepare_write_cmd(struct iscsi_task *task,
101 		       unsigned int imm_sz,
102 		       unsigned int unsol_sz,
103 		       unsigned int edtl)
104 {
105 	struct iscsi_iser_task *iser_task = task->dd_data;
106 	struct iser_device  *device = iser_task->iser_conn->ib_conn.device;
107 	struct iser_regd_buf *regd_buf;
108 	int err;
109 	struct iser_hdr *hdr = &iser_task->desc.iser_header;
110 	struct iser_data_buf *buf_out = &iser_task->data[ISER_DIR_OUT];
111 	struct ib_sge *tx_dsg = &iser_task->desc.tx_sg[1];
112 
113 	err = iser_dma_map_task_data(iser_task,
114 				     buf_out,
115 				     ISER_DIR_OUT,
116 				     DMA_TO_DEVICE);
117 	if (err)
118 		return err;
119 
120 	if (scsi_prot_sg_count(iser_task->sc)) {
121 		struct iser_data_buf *pbuf_out = &iser_task->prot[ISER_DIR_OUT];
122 
123 		err = iser_dma_map_task_data(iser_task,
124 					     pbuf_out,
125 					     ISER_DIR_OUT,
126 					     DMA_TO_DEVICE);
127 		if (err)
128 			return err;
129 	}
130 
131 	err = device->iser_reg_rdma_mem(iser_task, ISER_DIR_OUT);
132 	if (err != 0) {
133 		iser_err("Failed to register write cmd RDMA mem\n");
134 		return err;
135 	}
136 
137 	regd_buf = &iser_task->rdma_regd[ISER_DIR_OUT];
138 
139 	if (unsol_sz < edtl) {
140 		hdr->flags     |= ISER_WSV;
141 		hdr->write_stag = cpu_to_be32(regd_buf->reg.rkey);
142 		hdr->write_va   = cpu_to_be64(regd_buf->reg.va + unsol_sz);
143 
144 		iser_dbg("Cmd itt:%d, WRITE tags, RKEY:%#.4X "
145 			 "VA:%#llX + unsol:%d\n",
146 			 task->itt, regd_buf->reg.rkey,
147 			 (unsigned long long)regd_buf->reg.va, unsol_sz);
148 	}
149 
150 	if (imm_sz > 0) {
151 		iser_dbg("Cmd itt:%d, WRITE, adding imm.data sz: %d\n",
152 			 task->itt, imm_sz);
153 		tx_dsg->addr   = regd_buf->reg.va;
154 		tx_dsg->length = imm_sz;
155 		tx_dsg->lkey   = regd_buf->reg.lkey;
156 		iser_task->desc.num_sge = 2;
157 	}
158 
159 	return 0;
160 }
161 
162 /* creates a new tx descriptor and adds header regd buffer */
163 static void iser_create_send_desc(struct iser_conn	*iser_conn,
164 				  struct iser_tx_desc	*tx_desc)
165 {
166 	struct iser_device *device = iser_conn->ib_conn.device;
167 
168 	ib_dma_sync_single_for_cpu(device->ib_device,
169 		tx_desc->dma_addr, ISER_HEADERS_LEN, DMA_TO_DEVICE);
170 
171 	memset(&tx_desc->iser_header, 0, sizeof(struct iser_hdr));
172 	tx_desc->iser_header.flags = ISER_VER;
173 
174 	tx_desc->num_sge = 1;
175 
176 	if (tx_desc->tx_sg[0].lkey != device->mr->lkey) {
177 		tx_desc->tx_sg[0].lkey = device->mr->lkey;
178 		iser_dbg("sdesc %p lkey mismatch, fixing\n", tx_desc);
179 	}
180 }
181 
182 static void iser_free_login_buf(struct iser_conn *iser_conn)
183 {
184 	struct iser_device *device = iser_conn->ib_conn.device;
185 
186 	if (!iser_conn->login_buf)
187 		return;
188 
189 	if (iser_conn->login_req_dma)
190 		ib_dma_unmap_single(device->ib_device,
191 				    iser_conn->login_req_dma,
192 				    ISCSI_DEF_MAX_RECV_SEG_LEN, DMA_TO_DEVICE);
193 
194 	if (iser_conn->login_resp_dma)
195 		ib_dma_unmap_single(device->ib_device,
196 				    iser_conn->login_resp_dma,
197 				    ISER_RX_LOGIN_SIZE, DMA_FROM_DEVICE);
198 
199 	kfree(iser_conn->login_buf);
200 
201 	/* make sure we never redo any unmapping */
202 	iser_conn->login_req_dma = 0;
203 	iser_conn->login_resp_dma = 0;
204 	iser_conn->login_buf = NULL;
205 }
206 
207 static int iser_alloc_login_buf(struct iser_conn *iser_conn)
208 {
209 	struct iser_device *device = iser_conn->ib_conn.device;
210 	int			req_err, resp_err;
211 
212 	BUG_ON(device == NULL);
213 
214 	iser_conn->login_buf = kmalloc(ISCSI_DEF_MAX_RECV_SEG_LEN +
215 				     ISER_RX_LOGIN_SIZE, GFP_KERNEL);
216 	if (!iser_conn->login_buf)
217 		goto out_err;
218 
219 	iser_conn->login_req_buf  = iser_conn->login_buf;
220 	iser_conn->login_resp_buf = iser_conn->login_buf +
221 						ISCSI_DEF_MAX_RECV_SEG_LEN;
222 
223 	iser_conn->login_req_dma = ib_dma_map_single(device->ib_device,
224 						     iser_conn->login_req_buf,
225 						     ISCSI_DEF_MAX_RECV_SEG_LEN,
226 						     DMA_TO_DEVICE);
227 
228 	iser_conn->login_resp_dma = ib_dma_map_single(device->ib_device,
229 						      iser_conn->login_resp_buf,
230 						      ISER_RX_LOGIN_SIZE,
231 						      DMA_FROM_DEVICE);
232 
233 	req_err  = ib_dma_mapping_error(device->ib_device,
234 					iser_conn->login_req_dma);
235 	resp_err = ib_dma_mapping_error(device->ib_device,
236 					iser_conn->login_resp_dma);
237 
238 	if (req_err || resp_err) {
239 		if (req_err)
240 			iser_conn->login_req_dma = 0;
241 		if (resp_err)
242 			iser_conn->login_resp_dma = 0;
243 		goto free_login_buf;
244 	}
245 	return 0;
246 
247 free_login_buf:
248 	iser_free_login_buf(iser_conn);
249 
250 out_err:
251 	iser_err("unable to alloc or map login buf\n");
252 	return -ENOMEM;
253 }
254 
255 int iser_alloc_rx_descriptors(struct iser_conn *iser_conn,
256 			      struct iscsi_session *session)
257 {
258 	int i, j;
259 	u64 dma_addr;
260 	struct iser_rx_desc *rx_desc;
261 	struct ib_sge       *rx_sg;
262 	struct ib_conn *ib_conn = &iser_conn->ib_conn;
263 	struct iser_device *device = ib_conn->device;
264 
265 	iser_conn->qp_max_recv_dtos = session->cmds_max;
266 	iser_conn->qp_max_recv_dtos_mask = session->cmds_max - 1; /* cmds_max is 2^N */
267 	iser_conn->min_posted_rx = iser_conn->qp_max_recv_dtos >> 2;
268 
269 	if (device->iser_alloc_rdma_reg_res(ib_conn, session->scsi_cmds_max))
270 		goto create_rdma_reg_res_failed;
271 
272 	if (iser_alloc_login_buf(iser_conn))
273 		goto alloc_login_buf_fail;
274 
275 	iser_conn->num_rx_descs = session->cmds_max;
276 	iser_conn->rx_descs = kmalloc(iser_conn->num_rx_descs *
277 				sizeof(struct iser_rx_desc), GFP_KERNEL);
278 	if (!iser_conn->rx_descs)
279 		goto rx_desc_alloc_fail;
280 
281 	rx_desc = iser_conn->rx_descs;
282 
283 	for (i = 0; i < iser_conn->qp_max_recv_dtos; i++, rx_desc++)  {
284 		dma_addr = ib_dma_map_single(device->ib_device, (void *)rx_desc,
285 					ISER_RX_PAYLOAD_SIZE, DMA_FROM_DEVICE);
286 		if (ib_dma_mapping_error(device->ib_device, dma_addr))
287 			goto rx_desc_dma_map_failed;
288 
289 		rx_desc->dma_addr = dma_addr;
290 
291 		rx_sg = &rx_desc->rx_sg;
292 		rx_sg->addr   = rx_desc->dma_addr;
293 		rx_sg->length = ISER_RX_PAYLOAD_SIZE;
294 		rx_sg->lkey   = device->mr->lkey;
295 	}
296 
297 	iser_conn->rx_desc_head = 0;
298 	return 0;
299 
300 rx_desc_dma_map_failed:
301 	rx_desc = iser_conn->rx_descs;
302 	for (j = 0; j < i; j++, rx_desc++)
303 		ib_dma_unmap_single(device->ib_device, rx_desc->dma_addr,
304 				    ISER_RX_PAYLOAD_SIZE, DMA_FROM_DEVICE);
305 	kfree(iser_conn->rx_descs);
306 	iser_conn->rx_descs = NULL;
307 rx_desc_alloc_fail:
308 	iser_free_login_buf(iser_conn);
309 alloc_login_buf_fail:
310 	device->iser_free_rdma_reg_res(ib_conn);
311 create_rdma_reg_res_failed:
312 	iser_err("failed allocating rx descriptors / data buffers\n");
313 	return -ENOMEM;
314 }
315 
316 void iser_free_rx_descriptors(struct iser_conn *iser_conn)
317 {
318 	int i;
319 	struct iser_rx_desc *rx_desc;
320 	struct ib_conn *ib_conn = &iser_conn->ib_conn;
321 	struct iser_device *device = ib_conn->device;
322 
323 	if (!iser_conn->rx_descs)
324 		goto free_login_buf;
325 
326 	if (device->iser_free_rdma_reg_res)
327 		device->iser_free_rdma_reg_res(ib_conn);
328 
329 	rx_desc = iser_conn->rx_descs;
330 	for (i = 0; i < iser_conn->qp_max_recv_dtos; i++, rx_desc++)
331 		ib_dma_unmap_single(device->ib_device, rx_desc->dma_addr,
332 				    ISER_RX_PAYLOAD_SIZE, DMA_FROM_DEVICE);
333 	kfree(iser_conn->rx_descs);
334 	/* make sure we never redo any unmapping */
335 	iser_conn->rx_descs = NULL;
336 
337 free_login_buf:
338 	iser_free_login_buf(iser_conn);
339 }
340 
341 static int iser_post_rx_bufs(struct iscsi_conn *conn, struct iscsi_hdr *req)
342 {
343 	struct iser_conn *iser_conn = conn->dd_data;
344 	struct ib_conn *ib_conn = &iser_conn->ib_conn;
345 	struct iscsi_session *session = conn->session;
346 
347 	iser_dbg("req op %x flags %x\n", req->opcode, req->flags);
348 	/* check if this is the last login - going to full feature phase */
349 	if ((req->flags & ISCSI_FULL_FEATURE_PHASE) != ISCSI_FULL_FEATURE_PHASE)
350 		return 0;
351 
352 	/*
353 	 * Check that there is one posted recv buffer
354 	 * (for the last login response).
355 	 */
356 	WARN_ON(ib_conn->post_recv_buf_count != 1);
357 
358 	if (session->discovery_sess) {
359 		iser_info("Discovery session, re-using login RX buffer\n");
360 		return 0;
361 	} else
362 		iser_info("Normal session, posting batch of RX %d buffers\n",
363 			  iser_conn->min_posted_rx);
364 
365 	/* Initial post receive buffers */
366 	if (iser_post_recvm(iser_conn, iser_conn->min_posted_rx))
367 		return -ENOMEM;
368 
369 	return 0;
370 }
371 
372 static inline bool iser_signal_comp(u8 sig_count)
373 {
374 	return ((sig_count % ISER_SIGNAL_CMD_COUNT) == 0);
375 }
376 
377 /**
378  * iser_send_command - send command PDU
379  */
380 int iser_send_command(struct iscsi_conn *conn,
381 		      struct iscsi_task *task)
382 {
383 	struct iser_conn *iser_conn = conn->dd_data;
384 	struct iscsi_iser_task *iser_task = task->dd_data;
385 	unsigned long edtl;
386 	int err;
387 	struct iser_data_buf *data_buf, *prot_buf;
388 	struct iscsi_scsi_req *hdr = (struct iscsi_scsi_req *)task->hdr;
389 	struct scsi_cmnd *sc  =  task->sc;
390 	struct iser_tx_desc *tx_desc = &iser_task->desc;
391 	u8 sig_count = ++iser_conn->ib_conn.sig_count;
392 
393 	edtl = ntohl(hdr->data_length);
394 
395 	/* build the tx desc regd header and add it to the tx desc dto */
396 	tx_desc->type = ISCSI_TX_SCSI_COMMAND;
397 	iser_create_send_desc(iser_conn, tx_desc);
398 
399 	if (hdr->flags & ISCSI_FLAG_CMD_READ) {
400 		data_buf = &iser_task->data[ISER_DIR_IN];
401 		prot_buf = &iser_task->prot[ISER_DIR_IN];
402 	} else {
403 		data_buf = &iser_task->data[ISER_DIR_OUT];
404 		prot_buf = &iser_task->prot[ISER_DIR_OUT];
405 	}
406 
407 	if (scsi_sg_count(sc)) { /* using a scatter list */
408 		data_buf->buf  = scsi_sglist(sc);
409 		data_buf->size = scsi_sg_count(sc);
410 	}
411 	data_buf->data_len = scsi_bufflen(sc);
412 
413 	if (scsi_prot_sg_count(sc)) {
414 		prot_buf->buf  = scsi_prot_sglist(sc);
415 		prot_buf->size = scsi_prot_sg_count(sc);
416 		prot_buf->data_len = data_buf->data_len >>
417 				     ilog2(sc->device->sector_size) * 8;
418 	}
419 
420 	if (hdr->flags & ISCSI_FLAG_CMD_READ) {
421 		err = iser_prepare_read_cmd(task);
422 		if (err)
423 			goto send_command_error;
424 	}
425 	if (hdr->flags & ISCSI_FLAG_CMD_WRITE) {
426 		err = iser_prepare_write_cmd(task,
427 					     task->imm_count,
428 				             task->imm_count +
429 					     task->unsol_r2t.data_length,
430 					     edtl);
431 		if (err)
432 			goto send_command_error;
433 	}
434 
435 	iser_task->status = ISER_TASK_STATUS_STARTED;
436 
437 	err = iser_post_send(&iser_conn->ib_conn, tx_desc,
438 			     iser_signal_comp(sig_count));
439 	if (!err)
440 		return 0;
441 
442 send_command_error:
443 	iser_err("conn %p failed task->itt %d err %d\n",conn, task->itt, err);
444 	return err;
445 }
446 
447 /**
448  * iser_send_data_out - send data out PDU
449  */
450 int iser_send_data_out(struct iscsi_conn *conn,
451 		       struct iscsi_task *task,
452 		       struct iscsi_data *hdr)
453 {
454 	struct iser_conn *iser_conn = conn->dd_data;
455 	struct iscsi_iser_task *iser_task = task->dd_data;
456 	struct iser_tx_desc *tx_desc = NULL;
457 	struct iser_regd_buf *regd_buf;
458 	unsigned long buf_offset;
459 	unsigned long data_seg_len;
460 	uint32_t itt;
461 	int err = 0;
462 	struct ib_sge *tx_dsg;
463 
464 	itt = (__force uint32_t)hdr->itt;
465 	data_seg_len = ntoh24(hdr->dlength);
466 	buf_offset   = ntohl(hdr->offset);
467 
468 	iser_dbg("%s itt %d dseg_len %d offset %d\n",
469 		 __func__,(int)itt,(int)data_seg_len,(int)buf_offset);
470 
471 	tx_desc = kmem_cache_zalloc(ig.desc_cache, GFP_ATOMIC);
472 	if (tx_desc == NULL) {
473 		iser_err("Failed to alloc desc for post dataout\n");
474 		return -ENOMEM;
475 	}
476 
477 	tx_desc->type = ISCSI_TX_DATAOUT;
478 	tx_desc->iser_header.flags = ISER_VER;
479 	memcpy(&tx_desc->iscsi_header, hdr, sizeof(struct iscsi_hdr));
480 
481 	/* build the tx desc */
482 	iser_initialize_task_headers(task, tx_desc);
483 
484 	regd_buf = &iser_task->rdma_regd[ISER_DIR_OUT];
485 	tx_dsg = &tx_desc->tx_sg[1];
486 	tx_dsg->addr    = regd_buf->reg.va + buf_offset;
487 	tx_dsg->length  = data_seg_len;
488 	tx_dsg->lkey    = regd_buf->reg.lkey;
489 	tx_desc->num_sge = 2;
490 
491 	if (buf_offset + data_seg_len > iser_task->data[ISER_DIR_OUT].data_len) {
492 		iser_err("Offset:%ld & DSL:%ld in Data-Out "
493 			 "inconsistent with total len:%ld, itt:%d\n",
494 			 buf_offset, data_seg_len,
495 			 iser_task->data[ISER_DIR_OUT].data_len, itt);
496 		err = -EINVAL;
497 		goto send_data_out_error;
498 	}
499 	iser_dbg("data-out itt: %d, offset: %ld, sz: %ld\n",
500 		 itt, buf_offset, data_seg_len);
501 
502 
503 	err = iser_post_send(&iser_conn->ib_conn, tx_desc, true);
504 	if (!err)
505 		return 0;
506 
507 send_data_out_error:
508 	kmem_cache_free(ig.desc_cache, tx_desc);
509 	iser_err("conn %p failed err %d\n",conn, err);
510 	return err;
511 }
512 
513 int iser_send_control(struct iscsi_conn *conn,
514 		      struct iscsi_task *task)
515 {
516 	struct iser_conn *iser_conn = conn->dd_data;
517 	struct iscsi_iser_task *iser_task = task->dd_data;
518 	struct iser_tx_desc *mdesc = &iser_task->desc;
519 	unsigned long data_seg_len;
520 	int err = 0;
521 	struct iser_device *device;
522 
523 	/* build the tx desc regd header and add it to the tx desc dto */
524 	mdesc->type = ISCSI_TX_CONTROL;
525 	iser_create_send_desc(iser_conn, mdesc);
526 
527 	device = iser_conn->ib_conn.device;
528 
529 	data_seg_len = ntoh24(task->hdr->dlength);
530 
531 	if (data_seg_len > 0) {
532 		struct ib_sge *tx_dsg = &mdesc->tx_sg[1];
533 		if (task != conn->login_task) {
534 			iser_err("data present on non login task!!!\n");
535 			goto send_control_error;
536 		}
537 
538 		ib_dma_sync_single_for_cpu(device->ib_device,
539 			iser_conn->login_req_dma, task->data_count,
540 			DMA_TO_DEVICE);
541 
542 		memcpy(iser_conn->login_req_buf, task->data, task->data_count);
543 
544 		ib_dma_sync_single_for_device(device->ib_device,
545 			iser_conn->login_req_dma, task->data_count,
546 			DMA_TO_DEVICE);
547 
548 		tx_dsg->addr    = iser_conn->login_req_dma;
549 		tx_dsg->length  = task->data_count;
550 		tx_dsg->lkey    = device->mr->lkey;
551 		mdesc->num_sge = 2;
552 	}
553 
554 	if (task == conn->login_task) {
555 		iser_dbg("op %x dsl %lx, posting login rx buffer\n",
556 			 task->hdr->opcode, data_seg_len);
557 		err = iser_post_recvl(iser_conn);
558 		if (err)
559 			goto send_control_error;
560 		err = iser_post_rx_bufs(conn, task->hdr);
561 		if (err)
562 			goto send_control_error;
563 	}
564 
565 	err = iser_post_send(&iser_conn->ib_conn, mdesc, true);
566 	if (!err)
567 		return 0;
568 
569 send_control_error:
570 	iser_err("conn %p failed err %d\n",conn, err);
571 	return err;
572 }
573 
574 /**
575  * iser_rcv_dto_completion - recv DTO completion
576  */
577 void iser_rcv_completion(struct iser_rx_desc *rx_desc,
578 			 unsigned long rx_xfer_len,
579 			 struct ib_conn *ib_conn)
580 {
581 	struct iser_conn *iser_conn = container_of(ib_conn, struct iser_conn,
582 						   ib_conn);
583 	struct iscsi_hdr *hdr;
584 	u64 rx_dma;
585 	int rx_buflen, outstanding, count, err;
586 
587 	/* differentiate between login to all other PDUs */
588 	if ((char *)rx_desc == iser_conn->login_resp_buf) {
589 		rx_dma = iser_conn->login_resp_dma;
590 		rx_buflen = ISER_RX_LOGIN_SIZE;
591 	} else {
592 		rx_dma = rx_desc->dma_addr;
593 		rx_buflen = ISER_RX_PAYLOAD_SIZE;
594 	}
595 
596 	ib_dma_sync_single_for_cpu(ib_conn->device->ib_device, rx_dma,
597 				   rx_buflen, DMA_FROM_DEVICE);
598 
599 	hdr = &rx_desc->iscsi_header;
600 
601 	iser_dbg("op 0x%x itt 0x%x dlen %d\n", hdr->opcode,
602 			hdr->itt, (int)(rx_xfer_len - ISER_HEADERS_LEN));
603 
604 	iscsi_iser_recv(iser_conn->iscsi_conn, hdr, rx_desc->data,
605 			rx_xfer_len - ISER_HEADERS_LEN);
606 
607 	ib_dma_sync_single_for_device(ib_conn->device->ib_device, rx_dma,
608 				      rx_buflen, DMA_FROM_DEVICE);
609 
610 	/* decrementing conn->post_recv_buf_count only --after-- freeing the   *
611 	 * task eliminates the need to worry on tasks which are completed in   *
612 	 * parallel to the execution of iser_conn_term. So the code that waits *
613 	 * for the posted rx bufs refcount to become zero handles everything   */
614 	ib_conn->post_recv_buf_count--;
615 
616 	if (rx_dma == iser_conn->login_resp_dma)
617 		return;
618 
619 	outstanding = ib_conn->post_recv_buf_count;
620 	if (outstanding + iser_conn->min_posted_rx <= iser_conn->qp_max_recv_dtos) {
621 		count = min(iser_conn->qp_max_recv_dtos - outstanding,
622 			    iser_conn->min_posted_rx);
623 		err = iser_post_recvm(iser_conn, count);
624 		if (err)
625 			iser_err("posting %d rx bufs err %d\n", count, err);
626 	}
627 }
628 
629 void iser_snd_completion(struct iser_tx_desc *tx_desc,
630 			struct ib_conn *ib_conn)
631 {
632 	struct iscsi_task *task;
633 	struct iser_device *device = ib_conn->device;
634 
635 	if (tx_desc->type == ISCSI_TX_DATAOUT) {
636 		ib_dma_unmap_single(device->ib_device, tx_desc->dma_addr,
637 					ISER_HEADERS_LEN, DMA_TO_DEVICE);
638 		kmem_cache_free(ig.desc_cache, tx_desc);
639 		tx_desc = NULL;
640 	}
641 
642 	if (tx_desc && tx_desc->type == ISCSI_TX_CONTROL) {
643 		/* this arithmetic is legal by libiscsi dd_data allocation */
644 		task = (void *) ((long)(void *)tx_desc -
645 				  sizeof(struct iscsi_task));
646 		if (task->hdr->itt == RESERVED_ITT)
647 			iscsi_put_task(task);
648 	}
649 }
650 
651 void iser_task_rdma_init(struct iscsi_iser_task *iser_task)
652 
653 {
654 	iser_task->status = ISER_TASK_STATUS_INIT;
655 
656 	iser_task->dir[ISER_DIR_IN] = 0;
657 	iser_task->dir[ISER_DIR_OUT] = 0;
658 
659 	iser_task->data[ISER_DIR_IN].data_len  = 0;
660 	iser_task->data[ISER_DIR_OUT].data_len = 0;
661 
662 	iser_task->prot[ISER_DIR_IN].data_len  = 0;
663 	iser_task->prot[ISER_DIR_OUT].data_len = 0;
664 
665 	memset(&iser_task->rdma_regd[ISER_DIR_IN], 0,
666 	       sizeof(struct iser_regd_buf));
667 	memset(&iser_task->rdma_regd[ISER_DIR_OUT], 0,
668 	       sizeof(struct iser_regd_buf));
669 }
670 
671 void iser_task_rdma_finalize(struct iscsi_iser_task *iser_task)
672 {
673 	struct iser_device *device = iser_task->iser_conn->ib_conn.device;
674 	int is_rdma_data_aligned = 1;
675 	int is_rdma_prot_aligned = 1;
676 	int prot_count = scsi_prot_sg_count(iser_task->sc);
677 
678 	/* if we were reading, copy back to unaligned sglist,
679 	 * anyway dma_unmap and free the copy
680 	 */
681 	if (iser_task->data_copy[ISER_DIR_IN].copy_buf != NULL) {
682 		is_rdma_data_aligned = 0;
683 		iser_finalize_rdma_unaligned_sg(iser_task,
684 						&iser_task->data[ISER_DIR_IN],
685 						&iser_task->data_copy[ISER_DIR_IN],
686 						ISER_DIR_IN);
687 	}
688 
689 	if (iser_task->data_copy[ISER_DIR_OUT].copy_buf != NULL) {
690 		is_rdma_data_aligned = 0;
691 		iser_finalize_rdma_unaligned_sg(iser_task,
692 						&iser_task->data[ISER_DIR_OUT],
693 						&iser_task->data_copy[ISER_DIR_OUT],
694 						ISER_DIR_OUT);
695 	}
696 
697 	if (iser_task->prot_copy[ISER_DIR_IN].copy_buf != NULL) {
698 		is_rdma_prot_aligned = 0;
699 		iser_finalize_rdma_unaligned_sg(iser_task,
700 						&iser_task->prot[ISER_DIR_IN],
701 						&iser_task->prot_copy[ISER_DIR_IN],
702 						ISER_DIR_IN);
703 	}
704 
705 	if (iser_task->prot_copy[ISER_DIR_OUT].copy_buf != NULL) {
706 		is_rdma_prot_aligned = 0;
707 		iser_finalize_rdma_unaligned_sg(iser_task,
708 						&iser_task->prot[ISER_DIR_OUT],
709 						&iser_task->prot_copy[ISER_DIR_OUT],
710 						ISER_DIR_OUT);
711 	}
712 
713 	if (iser_task->dir[ISER_DIR_IN]) {
714 		device->iser_unreg_rdma_mem(iser_task, ISER_DIR_IN);
715 		if (is_rdma_data_aligned)
716 			iser_dma_unmap_task_data(iser_task,
717 						 &iser_task->data[ISER_DIR_IN]);
718 		if (prot_count && is_rdma_prot_aligned)
719 			iser_dma_unmap_task_data(iser_task,
720 						 &iser_task->prot[ISER_DIR_IN]);
721 	}
722 
723 	if (iser_task->dir[ISER_DIR_OUT]) {
724 		device->iser_unreg_rdma_mem(iser_task, ISER_DIR_OUT);
725 		if (is_rdma_data_aligned)
726 			iser_dma_unmap_task_data(iser_task,
727 						 &iser_task->data[ISER_DIR_OUT]);
728 		if (prot_count && is_rdma_prot_aligned)
729 			iser_dma_unmap_task_data(iser_task,
730 						 &iser_task->prot[ISER_DIR_OUT]);
731 	}
732 }
733