xref: /linux/drivers/infiniband/ulp/iser/iser_initiator.c (revision 5e8d780d745c1619aba81fe7166c5a4b5cad2b84)
1 /*
2  * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. All rights reserved.
3  *
4  * This software is available to you under a choice of one of two
5  * licenses.  You may choose to be licensed under the terms of the GNU
6  * General Public License (GPL) Version 2, available from the file
7  * COPYING in the main directory of this source tree, or the
8  * OpenIB.org BSD license below:
9  *
10  *     Redistribution and use in source and binary forms, with or
11  *     without modification, are permitted provided that the following
12  *     conditions are met:
13  *
14  *	- Redistributions of source code must retain the above
15  *	  copyright notice, this list of conditions and the following
16  *	  disclaimer.
17  *
18  *	- Redistributions in binary form must reproduce the above
19  *	  copyright notice, this list of conditions and the following
20  *	  disclaimer in the documentation and/or other materials
21  *	  provided with the distribution.
22  *
23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30  * SOFTWARE.
31  *
32  * $Id: iser_initiator.c 6964 2006-05-07 11:11:43Z ogerlitz $
33  */
34 #include <linux/kernel.h>
35 #include <linux/slab.h>
36 #include <linux/mm.h>
37 #include <asm/io.h>
38 #include <asm/scatterlist.h>
39 #include <linux/scatterlist.h>
40 #include <linux/kfifo.h>
41 #include <scsi/scsi_cmnd.h>
42 #include <scsi/scsi_host.h>
43 
44 #include "iscsi_iser.h"
45 
46 /* Constant PDU lengths calculations */
47 #define ISER_TOTAL_HEADERS_LEN  (sizeof (struct iser_hdr) + \
48 				 sizeof (struct iscsi_hdr))
49 
50 /* iser_dto_add_regd_buff - increments the reference count for *
51  * the registered buffer & adds it to the DTO object           */
52 static void iser_dto_add_regd_buff(struct iser_dto *dto,
53 				   struct iser_regd_buf *regd_buf,
54 				   unsigned long use_offset,
55 				   unsigned long use_size)
56 {
57 	int add_idx;
58 
59 	atomic_inc(&regd_buf->ref_count);
60 
61 	add_idx = dto->regd_vector_len;
62 	dto->regd[add_idx] = regd_buf;
63 	dto->used_sz[add_idx] = use_size;
64 	dto->offset[add_idx] = use_offset;
65 
66 	dto->regd_vector_len++;
67 }
68 
69 static int iser_dma_map_task_data(struct iscsi_iser_cmd_task *iser_ctask,
70 				  struct iser_data_buf       *data,
71 				  enum   iser_data_dir       iser_dir,
72 				  enum   dma_data_direction  dma_dir)
73 {
74 	struct device *dma_device;
75 
76 	iser_ctask->dir[iser_dir] = 1;
77 	dma_device = iser_ctask->iser_conn->ib_conn->device->ib_device->dma_device;
78 
79 	data->dma_nents = dma_map_sg(dma_device, data->buf, data->size, dma_dir);
80 	if (data->dma_nents == 0) {
81 		iser_err("dma_map_sg failed!!!\n");
82 		return -EINVAL;
83 	}
84 	return 0;
85 }
86 
87 static void iser_dma_unmap_task_data(struct iscsi_iser_cmd_task *iser_ctask)
88 {
89 	struct device  *dma_device;
90 	struct iser_data_buf *data;
91 
92 	dma_device = iser_ctask->iser_conn->ib_conn->device->ib_device->dma_device;
93 
94 	if (iser_ctask->dir[ISER_DIR_IN]) {
95 		data = &iser_ctask->data[ISER_DIR_IN];
96 		dma_unmap_sg(dma_device, data->buf, data->size, DMA_FROM_DEVICE);
97 	}
98 
99 	if (iser_ctask->dir[ISER_DIR_OUT]) {
100 		data = &iser_ctask->data[ISER_DIR_OUT];
101 		dma_unmap_sg(dma_device, data->buf, data->size, DMA_TO_DEVICE);
102 	}
103 }
104 
105 /* Register user buffer memory and initialize passive rdma
106  *  dto descriptor. Total data size is stored in
107  *  iser_ctask->data[ISER_DIR_IN].data_len
108  */
109 static int iser_prepare_read_cmd(struct iscsi_cmd_task *ctask,
110 				 unsigned int edtl)
111 
112 {
113 	struct iscsi_iser_cmd_task *iser_ctask = ctask->dd_data;
114 	struct iser_regd_buf *regd_buf;
115 	int err;
116 	struct iser_hdr *hdr = &iser_ctask->desc.iser_header;
117 	struct iser_data_buf *buf_in = &iser_ctask->data[ISER_DIR_IN];
118 
119 	err = iser_dma_map_task_data(iser_ctask,
120 				     buf_in,
121 				     ISER_DIR_IN,
122 				     DMA_FROM_DEVICE);
123 	if (err)
124 		return err;
125 
126 	if (edtl > iser_ctask->data[ISER_DIR_IN].data_len) {
127 		iser_err("Total data length: %ld, less than EDTL: "
128 			 "%d, in READ cmd BHS itt: %d, conn: 0x%p\n",
129 			 iser_ctask->data[ISER_DIR_IN].data_len, edtl,
130 			 ctask->itt, iser_ctask->iser_conn);
131 		return -EINVAL;
132 	}
133 
134 	err = iser_reg_rdma_mem(iser_ctask,ISER_DIR_IN);
135 	if (err) {
136 		iser_err("Failed to set up Data-IN RDMA\n");
137 		return err;
138 	}
139 	regd_buf = &iser_ctask->rdma_regd[ISER_DIR_IN];
140 
141 	hdr->flags    |= ISER_RSV;
142 	hdr->read_stag = cpu_to_be32(regd_buf->reg.rkey);
143 	hdr->read_va   = cpu_to_be64(regd_buf->reg.va);
144 
145 	iser_dbg("Cmd itt:%d READ tags RKEY:%#.4X VA:%#llX\n",
146 		 ctask->itt, regd_buf->reg.rkey,
147 		 (unsigned long long)regd_buf->reg.va);
148 
149 	return 0;
150 }
151 
152 /* Register user buffer memory and initialize passive rdma
153  *  dto descriptor. Total data size is stored in
154  *  ctask->data[ISER_DIR_OUT].data_len
155  */
156 static int
157 iser_prepare_write_cmd(struct iscsi_cmd_task *ctask,
158 		       unsigned int imm_sz,
159 		       unsigned int unsol_sz,
160 		       unsigned int edtl)
161 {
162 	struct iscsi_iser_cmd_task *iser_ctask = ctask->dd_data;
163 	struct iser_regd_buf *regd_buf;
164 	int err;
165 	struct iser_dto *send_dto = &iser_ctask->desc.dto;
166 	struct iser_hdr *hdr = &iser_ctask->desc.iser_header;
167 	struct iser_data_buf *buf_out = &iser_ctask->data[ISER_DIR_OUT];
168 
169 	err = iser_dma_map_task_data(iser_ctask,
170 				     buf_out,
171 				     ISER_DIR_OUT,
172 				     DMA_TO_DEVICE);
173 	if (err)
174 		return err;
175 
176 	if (edtl > iser_ctask->data[ISER_DIR_OUT].data_len) {
177 		iser_err("Total data length: %ld, less than EDTL: %d, "
178 			 "in WRITE cmd BHS itt: %d, conn: 0x%p\n",
179 			 iser_ctask->data[ISER_DIR_OUT].data_len,
180 			 edtl, ctask->itt, ctask->conn);
181 		return -EINVAL;
182 	}
183 
184 	err = iser_reg_rdma_mem(iser_ctask,ISER_DIR_OUT);
185 	if (err != 0) {
186 		iser_err("Failed to register write cmd RDMA mem\n");
187 		return err;
188 	}
189 
190 	regd_buf = &iser_ctask->rdma_regd[ISER_DIR_OUT];
191 
192 	if (unsol_sz < edtl) {
193 		hdr->flags     |= ISER_WSV;
194 		hdr->write_stag = cpu_to_be32(regd_buf->reg.rkey);
195 		hdr->write_va   = cpu_to_be64(regd_buf->reg.va + unsol_sz);
196 
197 		iser_dbg("Cmd itt:%d, WRITE tags, RKEY:%#.4X "
198 			 "VA:%#llX + unsol:%d\n",
199 			 ctask->itt, regd_buf->reg.rkey,
200 			 (unsigned long long)regd_buf->reg.va, unsol_sz);
201 	}
202 
203 	if (imm_sz > 0) {
204 		iser_dbg("Cmd itt:%d, WRITE, adding imm.data sz: %d\n",
205 			 ctask->itt, imm_sz);
206 		iser_dto_add_regd_buff(send_dto,
207 				       regd_buf,
208 				       0,
209 				       imm_sz);
210 	}
211 
212 	return 0;
213 }
214 
215 /**
216  * iser_post_receive_control - allocates, initializes and posts receive DTO.
217  */
218 static int iser_post_receive_control(struct iscsi_conn *conn)
219 {
220 	struct iscsi_iser_conn *iser_conn = conn->dd_data;
221 	struct iser_desc     *rx_desc;
222 	struct iser_regd_buf *regd_hdr;
223 	struct iser_regd_buf *regd_data;
224 	struct iser_dto      *recv_dto = NULL;
225 	struct iser_device  *device = iser_conn->ib_conn->device;
226 	int rx_data_size, err = 0;
227 
228 	rx_desc = kmem_cache_alloc(ig.desc_cache, GFP_NOIO);
229 	if (rx_desc == NULL) {
230 		iser_err("Failed to alloc desc for post recv\n");
231 		return -ENOMEM;
232 	}
233 	rx_desc->type = ISCSI_RX;
234 
235 	/* for the login sequence we must support rx of upto 8K; login is done
236 	 * after conn create/bind (connect) and conn stop/bind (reconnect),
237 	 * what's common for both schemes is that the connection is not started
238 	 */
239 	if (conn->c_stage != ISCSI_CONN_STARTED)
240 		rx_data_size = DEFAULT_MAX_RECV_DATA_SEGMENT_LENGTH;
241 	else /* FIXME till user space sets conn->max_recv_dlength correctly */
242 		rx_data_size = 128;
243 
244 	rx_desc->data = kmalloc(rx_data_size, GFP_NOIO);
245 	if (rx_desc->data == NULL) {
246 		iser_err("Failed to alloc data buf for post recv\n");
247 		err = -ENOMEM;
248 		goto post_rx_kmalloc_failure;
249 	}
250 
251 	recv_dto = &rx_desc->dto;
252 	recv_dto->conn          = iser_conn;
253 	recv_dto->regd_vector_len = 0;
254 
255 	regd_hdr = &rx_desc->hdr_regd_buf;
256 	memset(regd_hdr, 0, sizeof(struct iser_regd_buf));
257 	regd_hdr->device  = device;
258 	regd_hdr->virt_addr  = rx_desc; /* == &rx_desc->iser_header */
259 	regd_hdr->data_size  = ISER_TOTAL_HEADERS_LEN;
260 
261 	iser_reg_single(device, regd_hdr, DMA_FROM_DEVICE);
262 
263 	iser_dto_add_regd_buff(recv_dto, regd_hdr, 0, 0);
264 
265 	regd_data = &rx_desc->data_regd_buf;
266 	memset(regd_data, 0, sizeof(struct iser_regd_buf));
267 	regd_data->device  = device;
268 	regd_data->virt_addr  = rx_desc->data;
269 	regd_data->data_size  = rx_data_size;
270 
271 	iser_reg_single(device, regd_data, DMA_FROM_DEVICE);
272 
273 	iser_dto_add_regd_buff(recv_dto, regd_data, 0, 0);
274 
275 	err = iser_post_recv(rx_desc);
276 	if (!err)
277 		return 0;
278 
279 	/* iser_post_recv failed */
280 	iser_dto_buffs_release(recv_dto);
281 	kfree(rx_desc->data);
282 post_rx_kmalloc_failure:
283 	kmem_cache_free(ig.desc_cache, rx_desc);
284 	return err;
285 }
286 
287 /* creates a new tx descriptor and adds header regd buffer */
288 static void iser_create_send_desc(struct iscsi_iser_conn *iser_conn,
289 				  struct iser_desc       *tx_desc)
290 {
291 	struct iser_regd_buf *regd_hdr = &tx_desc->hdr_regd_buf;
292 	struct iser_dto      *send_dto = &tx_desc->dto;
293 
294 	memset(regd_hdr, 0, sizeof(struct iser_regd_buf));
295 	regd_hdr->device  = iser_conn->ib_conn->device;
296 	regd_hdr->virt_addr  = tx_desc; /* == &tx_desc->iser_header */
297 	regd_hdr->data_size  = ISER_TOTAL_HEADERS_LEN;
298 
299 	send_dto->conn          = iser_conn;
300 	send_dto->notify_enable   = 1;
301 	send_dto->regd_vector_len = 0;
302 
303 	memset(&tx_desc->iser_header, 0, sizeof(struct iser_hdr));
304 	tx_desc->iser_header.flags = ISER_VER;
305 
306 	iser_dto_add_regd_buff(send_dto, regd_hdr, 0, 0);
307 }
308 
309 /**
310  *  iser_conn_set_full_featured_mode - (iSER API)
311  */
312 int iser_conn_set_full_featured_mode(struct iscsi_conn *conn)
313 {
314 	struct iscsi_iser_conn *iser_conn = conn->dd_data;
315 
316 	int i;
317 	/* no need to keep it in a var, we are after login so if this should
318 	 * be negotiated, by now the result should be available here */
319 	int initial_post_recv_bufs_num = ISER_MAX_RX_MISC_PDUS;
320 
321 	iser_dbg("Initially post: %d\n", initial_post_recv_bufs_num);
322 
323 	/* Check that there is no posted recv or send buffers left - */
324 	/* they must be consumed during the login phase */
325 	BUG_ON(atomic_read(&iser_conn->ib_conn->post_recv_buf_count) != 0);
326 	BUG_ON(atomic_read(&iser_conn->ib_conn->post_send_buf_count) != 0);
327 
328 	/* Initial post receive buffers */
329 	for (i = 0; i < initial_post_recv_bufs_num; i++) {
330 		if (iser_post_receive_control(conn) != 0) {
331 			iser_err("Failed to post recv bufs at:%d conn:0x%p\n",
332 				 i, conn);
333 			return -ENOMEM;
334 		}
335 	}
336 	iser_dbg("Posted %d post recv bufs, conn:0x%p\n", i, conn);
337 	return 0;
338 }
339 
340 static int
341 iser_check_xmit(struct iscsi_conn *conn, void *task)
342 {
343 	int rc = 0;
344 	struct iscsi_iser_conn *iser_conn = conn->dd_data;
345 
346 	write_lock_bh(conn->recv_lock);
347 	if (atomic_read(&iser_conn->ib_conn->post_send_buf_count) ==
348 	    ISER_QP_MAX_REQ_DTOS) {
349 		iser_dbg("%ld can't xmit task %p, suspending tx\n",jiffies,task);
350 		set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
351 		rc = -EAGAIN;
352 	}
353 	write_unlock_bh(conn->recv_lock);
354 	return rc;
355 }
356 
357 
358 /**
359  * iser_send_command - send command PDU
360  */
361 int iser_send_command(struct iscsi_conn     *conn,
362 		      struct iscsi_cmd_task *ctask)
363 {
364 	struct iscsi_iser_conn *iser_conn = conn->dd_data;
365 	struct iscsi_iser_cmd_task *iser_ctask = ctask->dd_data;
366 	struct iser_dto *send_dto = NULL;
367 	unsigned long edtl;
368 	int err = 0;
369 	struct iser_data_buf *data_buf;
370 
371 	struct iscsi_cmd *hdr =  ctask->hdr;
372 	struct scsi_cmnd *sc  =  ctask->sc;
373 
374 	if (!iser_conn_state_comp(iser_conn->ib_conn, ISER_CONN_UP)) {
375 		iser_err("Failed to send, conn: 0x%p is not up\n", iser_conn->ib_conn);
376 		return -EPERM;
377 	}
378 	if (iser_check_xmit(conn, ctask))
379 		return -EAGAIN;
380 
381 	edtl = ntohl(hdr->data_length);
382 
383 	/* build the tx desc regd header and add it to the tx desc dto */
384 	iser_ctask->desc.type = ISCSI_TX_SCSI_COMMAND;
385 	send_dto = &iser_ctask->desc.dto;
386 	send_dto->ctask = iser_ctask;
387 	iser_create_send_desc(iser_conn, &iser_ctask->desc);
388 
389 	if (hdr->flags & ISCSI_FLAG_CMD_READ)
390 		data_buf = &iser_ctask->data[ISER_DIR_IN];
391 	else
392 		data_buf = &iser_ctask->data[ISER_DIR_OUT];
393 
394 	if (sc->use_sg) { /* using a scatter list */
395 		data_buf->buf  = sc->request_buffer;
396 		data_buf->size = sc->use_sg;
397 	} else if (sc->request_bufflen) {
398 		/* using a single buffer - convert it into one entry SG */
399 		sg_init_one(&data_buf->sg_single,
400 			    sc->request_buffer, sc->request_bufflen);
401 		data_buf->buf   = &data_buf->sg_single;
402 		data_buf->size  = 1;
403 	}
404 
405 	data_buf->data_len = sc->request_bufflen;
406 
407 	if (hdr->flags & ISCSI_FLAG_CMD_READ) {
408 		err = iser_prepare_read_cmd(ctask, edtl);
409 		if (err)
410 			goto send_command_error;
411 	}
412 	if (hdr->flags & ISCSI_FLAG_CMD_WRITE) {
413 		err = iser_prepare_write_cmd(ctask,
414 					     ctask->imm_count,
415 				             ctask->imm_count +
416 					     ctask->unsol_count,
417 					     edtl);
418 		if (err)
419 			goto send_command_error;
420 	}
421 
422 	iser_reg_single(iser_conn->ib_conn->device,
423 			send_dto->regd[0], DMA_TO_DEVICE);
424 
425 	if (iser_post_receive_control(conn) != 0) {
426 		iser_err("post_recv failed!\n");
427 		err = -ENOMEM;
428 		goto send_command_error;
429 	}
430 
431 	iser_ctask->status = ISER_TASK_STATUS_STARTED;
432 
433 	err = iser_post_send(&iser_ctask->desc);
434 	if (!err)
435 		return 0;
436 
437 send_command_error:
438 	iser_dto_buffs_release(send_dto);
439 	iser_err("conn %p failed ctask->itt %d err %d\n",conn, ctask->itt, err);
440 	return err;
441 }
442 
443 /**
444  * iser_send_data_out - send data out PDU
445  */
446 int iser_send_data_out(struct iscsi_conn     *conn,
447 		       struct iscsi_cmd_task *ctask,
448 		       struct iscsi_data *hdr)
449 {
450 	struct iscsi_iser_conn *iser_conn = conn->dd_data;
451 	struct iscsi_iser_cmd_task *iser_ctask = ctask->dd_data;
452 	struct iser_desc *tx_desc = NULL;
453 	struct iser_dto *send_dto = NULL;
454 	unsigned long buf_offset;
455 	unsigned long data_seg_len;
456 	unsigned int itt;
457 	int err = 0;
458 
459 	if (!iser_conn_state_comp(iser_conn->ib_conn, ISER_CONN_UP)) {
460 		iser_err("Failed to send, conn: 0x%p is not up\n", iser_conn->ib_conn);
461 		return -EPERM;
462 	}
463 
464 	if (iser_check_xmit(conn, ctask))
465 		return -EAGAIN;
466 
467 	itt = ntohl(hdr->itt);
468 	data_seg_len = ntoh24(hdr->dlength);
469 	buf_offset   = ntohl(hdr->offset);
470 
471 	iser_dbg("%s itt %d dseg_len %d offset %d\n",
472 		 __func__,(int)itt,(int)data_seg_len,(int)buf_offset);
473 
474 	tx_desc = kmem_cache_alloc(ig.desc_cache, GFP_NOIO);
475 	if (tx_desc == NULL) {
476 		iser_err("Failed to alloc desc for post dataout\n");
477 		return -ENOMEM;
478 	}
479 
480 	tx_desc->type = ISCSI_TX_DATAOUT;
481 	memcpy(&tx_desc->iscsi_header, hdr, sizeof(struct iscsi_hdr));
482 
483 	/* build the tx desc regd header and add it to the tx desc dto */
484 	send_dto = &tx_desc->dto;
485 	send_dto->ctask = iser_ctask;
486 	iser_create_send_desc(iser_conn, tx_desc);
487 
488 	iser_reg_single(iser_conn->ib_conn->device,
489 			send_dto->regd[0], DMA_TO_DEVICE);
490 
491 	/* all data was registered for RDMA, we can use the lkey */
492 	iser_dto_add_regd_buff(send_dto,
493 			       &iser_ctask->rdma_regd[ISER_DIR_OUT],
494 			       buf_offset,
495 			       data_seg_len);
496 
497 	if (buf_offset + data_seg_len > iser_ctask->data[ISER_DIR_OUT].data_len) {
498 		iser_err("Offset:%ld & DSL:%ld in Data-Out "
499 			 "inconsistent with total len:%ld, itt:%d\n",
500 			 buf_offset, data_seg_len,
501 			 iser_ctask->data[ISER_DIR_OUT].data_len, itt);
502 		err = -EINVAL;
503 		goto send_data_out_error;
504 	}
505 	iser_dbg("data-out itt: %d, offset: %ld, sz: %ld\n",
506 		 itt, buf_offset, data_seg_len);
507 
508 
509 	err = iser_post_send(tx_desc);
510 	if (!err)
511 		return 0;
512 
513 send_data_out_error:
514 	iser_dto_buffs_release(send_dto);
515 	kmem_cache_free(ig.desc_cache, tx_desc);
516 	iser_err("conn %p failed err %d\n",conn, err);
517 	return err;
518 }
519 
520 int iser_send_control(struct iscsi_conn *conn,
521 		      struct iscsi_mgmt_task *mtask)
522 {
523 	struct iscsi_iser_conn *iser_conn = conn->dd_data;
524 	struct iser_desc *mdesc = mtask->dd_data;
525 	struct iser_dto *send_dto = NULL;
526 	unsigned int itt;
527 	unsigned long data_seg_len;
528 	int err = 0;
529 	unsigned char opcode;
530 	struct iser_regd_buf *regd_buf;
531 	struct iser_device *device;
532 
533 	if (!iser_conn_state_comp(iser_conn->ib_conn, ISER_CONN_UP)) {
534 		iser_err("Failed to send, conn: 0x%p is not up\n", iser_conn->ib_conn);
535 		return -EPERM;
536 	}
537 
538 	if (iser_check_xmit(conn,mtask))
539 		return -EAGAIN;
540 
541 	/* build the tx desc regd header and add it to the tx desc dto */
542 	mdesc->type = ISCSI_TX_CONTROL;
543 	send_dto = &mdesc->dto;
544 	send_dto->ctask = NULL;
545 	iser_create_send_desc(iser_conn, mdesc);
546 
547 	device = iser_conn->ib_conn->device;
548 
549 	iser_reg_single(device, send_dto->regd[0], DMA_TO_DEVICE);
550 
551 	itt = ntohl(mtask->hdr->itt);
552 	opcode = mtask->hdr->opcode & ISCSI_OPCODE_MASK;
553 	data_seg_len = ntoh24(mtask->hdr->dlength);
554 
555 	if (data_seg_len > 0) {
556 		regd_buf = &mdesc->data_regd_buf;
557 		memset(regd_buf, 0, sizeof(struct iser_regd_buf));
558 		regd_buf->device = device;
559 		regd_buf->virt_addr = mtask->data;
560 		regd_buf->data_size = mtask->data_count;
561 		iser_reg_single(device, regd_buf,
562 				DMA_TO_DEVICE);
563 		iser_dto_add_regd_buff(send_dto, regd_buf,
564 				       0,
565 				       data_seg_len);
566 	}
567 
568 	if (iser_post_receive_control(conn) != 0) {
569 		iser_err("post_rcv_buff failed!\n");
570 		err = -ENOMEM;
571 		goto send_control_error;
572 	}
573 
574 	err = iser_post_send(mdesc);
575 	if (!err)
576 		return 0;
577 
578 send_control_error:
579 	iser_dto_buffs_release(send_dto);
580 	iser_err("conn %p failed err %d\n",conn, err);
581 	return err;
582 }
583 
584 /**
585  * iser_rcv_dto_completion - recv DTO completion
586  */
587 void iser_rcv_completion(struct iser_desc *rx_desc,
588 			 unsigned long dto_xfer_len)
589 {
590 	struct iser_dto        *dto = &rx_desc->dto;
591 	struct iscsi_iser_conn *conn = dto->conn;
592 	struct iscsi_session *session = conn->iscsi_conn->session;
593 	struct iscsi_cmd_task *ctask;
594 	struct iscsi_iser_cmd_task *iser_ctask;
595 	struct iscsi_hdr *hdr;
596 	char   *rx_data = NULL;
597 	int     rx_data_len = 0;
598 	unsigned int itt;
599 	unsigned char opcode;
600 
601 	hdr = &rx_desc->iscsi_header;
602 
603 	iser_dbg("op 0x%x itt 0x%x\n", hdr->opcode,hdr->itt);
604 
605 	if (dto_xfer_len > ISER_TOTAL_HEADERS_LEN) { /* we have data */
606 		rx_data_len = dto_xfer_len - ISER_TOTAL_HEADERS_LEN;
607 		rx_data     = dto->regd[1]->virt_addr;
608 		rx_data    += dto->offset[1];
609 	}
610 
611 	opcode = hdr->opcode & ISCSI_OPCODE_MASK;
612 
613 	if (opcode == ISCSI_OP_SCSI_CMD_RSP) {
614 	        itt = hdr->itt & ISCSI_ITT_MASK; /* mask out cid and age bits */
615 		if (!(itt < session->cmds_max))
616 			iser_err("itt can't be matched to task!!!"
617 				 "conn %p opcode %d cmds_max %d itt %d\n",
618 				 conn->iscsi_conn,opcode,session->cmds_max,itt);
619 		/* use the mapping given with the cmds array indexed by itt */
620 		ctask = (struct iscsi_cmd_task *)session->cmds[itt];
621 		iser_ctask = ctask->dd_data;
622 		iser_dbg("itt %d ctask %p\n",itt,ctask);
623 		iser_ctask->status = ISER_TASK_STATUS_COMPLETED;
624 		iser_ctask_rdma_finalize(iser_ctask);
625 	}
626 
627 	iser_dto_buffs_release(dto);
628 
629 	iscsi_iser_recv(conn->iscsi_conn, hdr, rx_data, rx_data_len);
630 
631 	kfree(rx_desc->data);
632 	kmem_cache_free(ig.desc_cache, rx_desc);
633 
634 	/* decrementing conn->post_recv_buf_count only --after-- freeing the   *
635 	 * task eliminates the need to worry on tasks which are completed in   *
636 	 * parallel to the execution of iser_conn_term. So the code that waits *
637 	 * for the posted rx bufs refcount to become zero handles everything   */
638 	atomic_dec(&conn->ib_conn->post_recv_buf_count);
639 }
640 
641 void iser_snd_completion(struct iser_desc *tx_desc)
642 {
643 	struct iser_dto        *dto = &tx_desc->dto;
644 	struct iscsi_iser_conn *iser_conn = dto->conn;
645 	struct iscsi_conn      *conn = iser_conn->iscsi_conn;
646 	struct iscsi_mgmt_task *mtask;
647 
648 	iser_dbg("Initiator, Data sent dto=0x%p\n", dto);
649 
650 	iser_dto_buffs_release(dto);
651 
652 	if (tx_desc->type == ISCSI_TX_DATAOUT)
653 		kmem_cache_free(ig.desc_cache, tx_desc);
654 
655 	atomic_dec(&iser_conn->ib_conn->post_send_buf_count);
656 
657 	write_lock(conn->recv_lock);
658 	if (conn->suspend_tx) {
659 		iser_dbg("%ld resuming tx\n",jiffies);
660 		clear_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
661 		scsi_queue_work(conn->session->host, &conn->xmitwork);
662 	}
663 	write_unlock(conn->recv_lock);
664 
665 	if (tx_desc->type == ISCSI_TX_CONTROL) {
666 		/* this arithmetic is legal by libiscsi dd_data allocation */
667 		mtask = (void *) ((long)(void *)tx_desc -
668 				  sizeof(struct iscsi_mgmt_task));
669 		if (mtask->hdr->itt == cpu_to_be32(ISCSI_RESERVED_TAG)) {
670 			struct iscsi_session *session = conn->session;
671 
672 			spin_lock(&conn->session->lock);
673 			list_del(&mtask->running);
674 			__kfifo_put(session->mgmtpool.queue, (void*)&mtask,
675 				    sizeof(void*));
676 			spin_unlock(&session->lock);
677 		}
678 	}
679 }
680 
681 void iser_ctask_rdma_init(struct iscsi_iser_cmd_task *iser_ctask)
682 
683 {
684 	iser_ctask->status = ISER_TASK_STATUS_INIT;
685 
686 	iser_ctask->dir[ISER_DIR_IN] = 0;
687 	iser_ctask->dir[ISER_DIR_OUT] = 0;
688 
689 	iser_ctask->data[ISER_DIR_IN].data_len  = 0;
690 	iser_ctask->data[ISER_DIR_OUT].data_len = 0;
691 
692 	memset(&iser_ctask->rdma_regd[ISER_DIR_IN], 0,
693 	       sizeof(struct iser_regd_buf));
694 	memset(&iser_ctask->rdma_regd[ISER_DIR_OUT], 0,
695 	       sizeof(struct iser_regd_buf));
696 }
697 
698 void iser_ctask_rdma_finalize(struct iscsi_iser_cmd_task *iser_ctask)
699 {
700 	int deferred;
701 
702 	/* if we were reading, copy back to unaligned sglist,
703 	 * anyway dma_unmap and free the copy
704 	 */
705 	if (iser_ctask->data_copy[ISER_DIR_IN].copy_buf != NULL)
706 		iser_finalize_rdma_unaligned_sg(iser_ctask, ISER_DIR_IN);
707 	if (iser_ctask->data_copy[ISER_DIR_OUT].copy_buf != NULL)
708 		iser_finalize_rdma_unaligned_sg(iser_ctask, ISER_DIR_OUT);
709 
710 	if (iser_ctask->dir[ISER_DIR_IN]) {
711 		deferred = iser_regd_buff_release
712 			(&iser_ctask->rdma_regd[ISER_DIR_IN]);
713 		if (deferred) {
714 			iser_err("References remain for BUF-IN rdma reg\n");
715 			BUG();
716 		}
717 	}
718 
719 	if (iser_ctask->dir[ISER_DIR_OUT]) {
720 		deferred = iser_regd_buff_release
721 			(&iser_ctask->rdma_regd[ISER_DIR_OUT]);
722 		if (deferred) {
723 			iser_err("References remain for BUF-OUT rdma reg\n");
724 			BUG();
725 		}
726 	}
727 
728 	iser_dma_unmap_task_data(iser_ctask);
729 }
730 
731 void iser_dto_buffs_release(struct iser_dto *dto)
732 {
733 	int i;
734 
735 	for (i = 0; i < dto->regd_vector_len; i++)
736 		iser_regd_buff_release(dto->regd[i]);
737 }
738 
739