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 <linux/scatterlist.h>
38 #include <linux/kfifo.h>
39 #include <scsi/scsi_cmnd.h>
40 #include <scsi/scsi_host.h>
41 
42 #include "iscsi_iser.h"
43 
44 /* Constant PDU lengths calculations */
45 #define ISER_TOTAL_HEADERS_LEN  (sizeof (struct iser_hdr) + \
46 				 sizeof (struct iscsi_hdr))
47 
48 /* iser_dto_add_regd_buff - increments the reference count for *
49  * the registered buffer & adds it to the DTO object           */
50 static void iser_dto_add_regd_buff(struct iser_dto *dto,
51 				   struct iser_regd_buf *regd_buf,
52 				   unsigned long use_offset,
53 				   unsigned long use_size)
54 {
55 	int add_idx;
56 
57 	atomic_inc(&regd_buf->ref_count);
58 
59 	add_idx = dto->regd_vector_len;
60 	dto->regd[add_idx] = regd_buf;
61 	dto->used_sz[add_idx] = use_size;
62 	dto->offset[add_idx] = use_offset;
63 
64 	dto->regd_vector_len++;
65 }
66 
67 /* Register user buffer memory and initialize passive rdma
68  *  dto descriptor. Total data size is stored in
69  *  iser_ctask->data[ISER_DIR_IN].data_len
70  */
71 static int iser_prepare_read_cmd(struct iscsi_cmd_task *ctask,
72 				 unsigned int edtl)
73 
74 {
75 	struct iscsi_iser_cmd_task *iser_ctask = ctask->dd_data;
76 	struct iser_regd_buf *regd_buf;
77 	int err;
78 	struct iser_hdr *hdr = &iser_ctask->desc.iser_header;
79 	struct iser_data_buf *buf_in = &iser_ctask->data[ISER_DIR_IN];
80 
81 	err = iser_dma_map_task_data(iser_ctask,
82 				     buf_in,
83 				     ISER_DIR_IN,
84 				     DMA_FROM_DEVICE);
85 	if (err)
86 		return err;
87 
88 	if (edtl > iser_ctask->data[ISER_DIR_IN].data_len) {
89 		iser_err("Total data length: %ld, less than EDTL: "
90 			 "%d, in READ cmd BHS itt: %d, conn: 0x%p\n",
91 			 iser_ctask->data[ISER_DIR_IN].data_len, edtl,
92 			 ctask->itt, iser_ctask->iser_conn);
93 		return -EINVAL;
94 	}
95 
96 	err = iser_reg_rdma_mem(iser_ctask,ISER_DIR_IN);
97 	if (err) {
98 		iser_err("Failed to set up Data-IN RDMA\n");
99 		return err;
100 	}
101 	regd_buf = &iser_ctask->rdma_regd[ISER_DIR_IN];
102 
103 	hdr->flags    |= ISER_RSV;
104 	hdr->read_stag = cpu_to_be32(regd_buf->reg.rkey);
105 	hdr->read_va   = cpu_to_be64(regd_buf->reg.va);
106 
107 	iser_dbg("Cmd itt:%d READ tags RKEY:%#.4X VA:%#llX\n",
108 		 ctask->itt, regd_buf->reg.rkey,
109 		 (unsigned long long)regd_buf->reg.va);
110 
111 	return 0;
112 }
113 
114 /* Register user buffer memory and initialize passive rdma
115  *  dto descriptor. Total data size is stored in
116  *  ctask->data[ISER_DIR_OUT].data_len
117  */
118 static int
119 iser_prepare_write_cmd(struct iscsi_cmd_task *ctask,
120 		       unsigned int imm_sz,
121 		       unsigned int unsol_sz,
122 		       unsigned int edtl)
123 {
124 	struct iscsi_iser_cmd_task *iser_ctask = ctask->dd_data;
125 	struct iser_regd_buf *regd_buf;
126 	int err;
127 	struct iser_dto *send_dto = &iser_ctask->desc.dto;
128 	struct iser_hdr *hdr = &iser_ctask->desc.iser_header;
129 	struct iser_data_buf *buf_out = &iser_ctask->data[ISER_DIR_OUT];
130 
131 	err = iser_dma_map_task_data(iser_ctask,
132 				     buf_out,
133 				     ISER_DIR_OUT,
134 				     DMA_TO_DEVICE);
135 	if (err)
136 		return err;
137 
138 	if (edtl > iser_ctask->data[ISER_DIR_OUT].data_len) {
139 		iser_err("Total data length: %ld, less than EDTL: %d, "
140 			 "in WRITE cmd BHS itt: %d, conn: 0x%p\n",
141 			 iser_ctask->data[ISER_DIR_OUT].data_len,
142 			 edtl, ctask->itt, ctask->conn);
143 		return -EINVAL;
144 	}
145 
146 	err = iser_reg_rdma_mem(iser_ctask,ISER_DIR_OUT);
147 	if (err != 0) {
148 		iser_err("Failed to register write cmd RDMA mem\n");
149 		return err;
150 	}
151 
152 	regd_buf = &iser_ctask->rdma_regd[ISER_DIR_OUT];
153 
154 	if (unsol_sz < edtl) {
155 		hdr->flags     |= ISER_WSV;
156 		hdr->write_stag = cpu_to_be32(regd_buf->reg.rkey);
157 		hdr->write_va   = cpu_to_be64(regd_buf->reg.va + unsol_sz);
158 
159 		iser_dbg("Cmd itt:%d, WRITE tags, RKEY:%#.4X "
160 			 "VA:%#llX + unsol:%d\n",
161 			 ctask->itt, regd_buf->reg.rkey,
162 			 (unsigned long long)regd_buf->reg.va, unsol_sz);
163 	}
164 
165 	if (imm_sz > 0) {
166 		iser_dbg("Cmd itt:%d, WRITE, adding imm.data sz: %d\n",
167 			 ctask->itt, imm_sz);
168 		iser_dto_add_regd_buff(send_dto,
169 				       regd_buf,
170 				       0,
171 				       imm_sz);
172 	}
173 
174 	return 0;
175 }
176 
177 /**
178  * iser_post_receive_control - allocates, initializes and posts receive DTO.
179  */
180 static int iser_post_receive_control(struct iscsi_conn *conn)
181 {
182 	struct iscsi_iser_conn *iser_conn = conn->dd_data;
183 	struct iser_desc     *rx_desc;
184 	struct iser_regd_buf *regd_hdr;
185 	struct iser_regd_buf *regd_data;
186 	struct iser_dto      *recv_dto = NULL;
187 	struct iser_device  *device = iser_conn->ib_conn->device;
188 	int rx_data_size, err = 0;
189 
190 	rx_desc = kmem_cache_alloc(ig.desc_cache, GFP_NOIO);
191 	if (rx_desc == NULL) {
192 		iser_err("Failed to alloc desc for post recv\n");
193 		return -ENOMEM;
194 	}
195 	rx_desc->type = ISCSI_RX;
196 
197 	/* for the login sequence we must support rx of upto 8K; login is done
198 	 * after conn create/bind (connect) and conn stop/bind (reconnect),
199 	 * what's common for both schemes is that the connection is not started
200 	 */
201 	if (conn->c_stage != ISCSI_CONN_STARTED)
202 		rx_data_size = ISCSI_DEF_MAX_RECV_SEG_LEN;
203 	else /* FIXME till user space sets conn->max_recv_dlength correctly */
204 		rx_data_size = 128;
205 
206 	rx_desc->data = kmalloc(rx_data_size, GFP_NOIO);
207 	if (rx_desc->data == NULL) {
208 		iser_err("Failed to alloc data buf for post recv\n");
209 		err = -ENOMEM;
210 		goto post_rx_kmalloc_failure;
211 	}
212 
213 	recv_dto = &rx_desc->dto;
214 	recv_dto->ib_conn = iser_conn->ib_conn;
215 	recv_dto->regd_vector_len = 0;
216 
217 	regd_hdr = &rx_desc->hdr_regd_buf;
218 	memset(regd_hdr, 0, sizeof(struct iser_regd_buf));
219 	regd_hdr->device  = device;
220 	regd_hdr->virt_addr  = rx_desc; /* == &rx_desc->iser_header */
221 	regd_hdr->data_size  = ISER_TOTAL_HEADERS_LEN;
222 
223 	iser_reg_single(device, regd_hdr, DMA_FROM_DEVICE);
224 
225 	iser_dto_add_regd_buff(recv_dto, regd_hdr, 0, 0);
226 
227 	regd_data = &rx_desc->data_regd_buf;
228 	memset(regd_data, 0, sizeof(struct iser_regd_buf));
229 	regd_data->device  = device;
230 	regd_data->virt_addr  = rx_desc->data;
231 	regd_data->data_size  = rx_data_size;
232 
233 	iser_reg_single(device, regd_data, DMA_FROM_DEVICE);
234 
235 	iser_dto_add_regd_buff(recv_dto, regd_data, 0, 0);
236 
237 	err = iser_post_recv(rx_desc);
238 	if (!err)
239 		return 0;
240 
241 	/* iser_post_recv failed */
242 	iser_dto_buffs_release(recv_dto);
243 	kfree(rx_desc->data);
244 post_rx_kmalloc_failure:
245 	kmem_cache_free(ig.desc_cache, rx_desc);
246 	return err;
247 }
248 
249 /* creates a new tx descriptor and adds header regd buffer */
250 static void iser_create_send_desc(struct iscsi_iser_conn *iser_conn,
251 				  struct iser_desc       *tx_desc)
252 {
253 	struct iser_regd_buf *regd_hdr = &tx_desc->hdr_regd_buf;
254 	struct iser_dto      *send_dto = &tx_desc->dto;
255 
256 	memset(regd_hdr, 0, sizeof(struct iser_regd_buf));
257 	regd_hdr->device  = iser_conn->ib_conn->device;
258 	regd_hdr->virt_addr  = tx_desc; /* == &tx_desc->iser_header */
259 	regd_hdr->data_size  = ISER_TOTAL_HEADERS_LEN;
260 
261 	send_dto->ib_conn         = iser_conn->ib_conn;
262 	send_dto->notify_enable   = 1;
263 	send_dto->regd_vector_len = 0;
264 
265 	memset(&tx_desc->iser_header, 0, sizeof(struct iser_hdr));
266 	tx_desc->iser_header.flags = ISER_VER;
267 
268 	iser_dto_add_regd_buff(send_dto, regd_hdr, 0, 0);
269 }
270 
271 /**
272  *  iser_conn_set_full_featured_mode - (iSER API)
273  */
274 int iser_conn_set_full_featured_mode(struct iscsi_conn *conn)
275 {
276 	struct iscsi_iser_conn *iser_conn = conn->dd_data;
277 
278 	int i;
279 	/* no need to keep it in a var, we are after login so if this should
280 	 * be negotiated, by now the result should be available here */
281 	int initial_post_recv_bufs_num = ISER_MAX_RX_MISC_PDUS;
282 
283 	iser_dbg("Initially post: %d\n", initial_post_recv_bufs_num);
284 
285 	/* Check that there is no posted recv or send buffers left - */
286 	/* they must be consumed during the login phase */
287 	BUG_ON(atomic_read(&iser_conn->ib_conn->post_recv_buf_count) != 0);
288 	BUG_ON(atomic_read(&iser_conn->ib_conn->post_send_buf_count) != 0);
289 
290 	/* Initial post receive buffers */
291 	for (i = 0; i < initial_post_recv_bufs_num; i++) {
292 		if (iser_post_receive_control(conn) != 0) {
293 			iser_err("Failed to post recv bufs at:%d conn:0x%p\n",
294 				 i, conn);
295 			return -ENOMEM;
296 		}
297 	}
298 	iser_dbg("Posted %d post recv bufs, conn:0x%p\n", i, conn);
299 	return 0;
300 }
301 
302 static int
303 iser_check_xmit(struct iscsi_conn *conn, void *task)
304 {
305 	struct iscsi_iser_conn *iser_conn = conn->dd_data;
306 
307 	if (atomic_read(&iser_conn->ib_conn->post_send_buf_count) ==
308 	    ISER_QP_MAX_REQ_DTOS) {
309 		iser_dbg("%ld can't xmit task %p\n",jiffies,task);
310 		return -ENOBUFS;
311 	}
312 	return 0;
313 }
314 
315 
316 /**
317  * iser_send_command - send command PDU
318  */
319 int iser_send_command(struct iscsi_conn     *conn,
320 		      struct iscsi_cmd_task *ctask)
321 {
322 	struct iscsi_iser_conn *iser_conn = conn->dd_data;
323 	struct iscsi_iser_cmd_task *iser_ctask = ctask->dd_data;
324 	struct iser_dto *send_dto = NULL;
325 	unsigned long edtl;
326 	int err = 0;
327 	struct iser_data_buf *data_buf;
328 
329 	struct iscsi_cmd *hdr =  ctask->hdr;
330 	struct scsi_cmnd *sc  =  ctask->sc;
331 
332 	if (!iser_conn_state_comp(iser_conn->ib_conn, ISER_CONN_UP)) {
333 		iser_err("Failed to send, conn: 0x%p is not up\n", iser_conn->ib_conn);
334 		return -EPERM;
335 	}
336 	if (iser_check_xmit(conn, ctask))
337 		return -ENOBUFS;
338 
339 	edtl = ntohl(hdr->data_length);
340 
341 	/* build the tx desc regd header and add it to the tx desc dto */
342 	iser_ctask->desc.type = ISCSI_TX_SCSI_COMMAND;
343 	send_dto = &iser_ctask->desc.dto;
344 	send_dto->ctask = iser_ctask;
345 	iser_create_send_desc(iser_conn, &iser_ctask->desc);
346 
347 	if (hdr->flags & ISCSI_FLAG_CMD_READ)
348 		data_buf = &iser_ctask->data[ISER_DIR_IN];
349 	else
350 		data_buf = &iser_ctask->data[ISER_DIR_OUT];
351 
352 	if (scsi_sg_count(sc)) { /* using a scatter list */
353 		data_buf->buf  = scsi_sglist(sc);
354 		data_buf->size = scsi_sg_count(sc);
355 	}
356 
357 	data_buf->data_len = scsi_bufflen(sc);
358 
359 	if (hdr->flags & ISCSI_FLAG_CMD_READ) {
360 		err = iser_prepare_read_cmd(ctask, edtl);
361 		if (err)
362 			goto send_command_error;
363 	}
364 	if (hdr->flags & ISCSI_FLAG_CMD_WRITE) {
365 		err = iser_prepare_write_cmd(ctask,
366 					     ctask->imm_count,
367 				             ctask->imm_count +
368 					     ctask->unsol_count,
369 					     edtl);
370 		if (err)
371 			goto send_command_error;
372 	}
373 
374 	iser_reg_single(iser_conn->ib_conn->device,
375 			send_dto->regd[0], DMA_TO_DEVICE);
376 
377 	if (iser_post_receive_control(conn) != 0) {
378 		iser_err("post_recv failed!\n");
379 		err = -ENOMEM;
380 		goto send_command_error;
381 	}
382 
383 	iser_ctask->status = ISER_TASK_STATUS_STARTED;
384 
385 	err = iser_post_send(&iser_ctask->desc);
386 	if (!err)
387 		return 0;
388 
389 send_command_error:
390 	iser_dto_buffs_release(send_dto);
391 	iser_err("conn %p failed ctask->itt %d err %d\n",conn, ctask->itt, err);
392 	return err;
393 }
394 
395 /**
396  * iser_send_data_out - send data out PDU
397  */
398 int iser_send_data_out(struct iscsi_conn     *conn,
399 		       struct iscsi_cmd_task *ctask,
400 		       struct iscsi_data *hdr)
401 {
402 	struct iscsi_iser_conn *iser_conn = conn->dd_data;
403 	struct iscsi_iser_cmd_task *iser_ctask = ctask->dd_data;
404 	struct iser_desc *tx_desc = NULL;
405 	struct iser_dto *send_dto = NULL;
406 	unsigned long buf_offset;
407 	unsigned long data_seg_len;
408 	uint32_t itt;
409 	int err = 0;
410 
411 	if (!iser_conn_state_comp(iser_conn->ib_conn, ISER_CONN_UP)) {
412 		iser_err("Failed to send, conn: 0x%p is not up\n", iser_conn->ib_conn);
413 		return -EPERM;
414 	}
415 
416 	if (iser_check_xmit(conn, ctask))
417 		return -ENOBUFS;
418 
419 	itt = (__force uint32_t)hdr->itt;
420 	data_seg_len = ntoh24(hdr->dlength);
421 	buf_offset   = ntohl(hdr->offset);
422 
423 	iser_dbg("%s itt %d dseg_len %d offset %d\n",
424 		 __func__,(int)itt,(int)data_seg_len,(int)buf_offset);
425 
426 	tx_desc = kmem_cache_alloc(ig.desc_cache, GFP_NOIO);
427 	if (tx_desc == NULL) {
428 		iser_err("Failed to alloc desc for post dataout\n");
429 		return -ENOMEM;
430 	}
431 
432 	tx_desc->type = ISCSI_TX_DATAOUT;
433 	memcpy(&tx_desc->iscsi_header, hdr, sizeof(struct iscsi_hdr));
434 
435 	/* build the tx desc regd header and add it to the tx desc dto */
436 	send_dto = &tx_desc->dto;
437 	send_dto->ctask = iser_ctask;
438 	iser_create_send_desc(iser_conn, tx_desc);
439 
440 	iser_reg_single(iser_conn->ib_conn->device,
441 			send_dto->regd[0], DMA_TO_DEVICE);
442 
443 	/* all data was registered for RDMA, we can use the lkey */
444 	iser_dto_add_regd_buff(send_dto,
445 			       &iser_ctask->rdma_regd[ISER_DIR_OUT],
446 			       buf_offset,
447 			       data_seg_len);
448 
449 	if (buf_offset + data_seg_len > iser_ctask->data[ISER_DIR_OUT].data_len) {
450 		iser_err("Offset:%ld & DSL:%ld in Data-Out "
451 			 "inconsistent with total len:%ld, itt:%d\n",
452 			 buf_offset, data_seg_len,
453 			 iser_ctask->data[ISER_DIR_OUT].data_len, itt);
454 		err = -EINVAL;
455 		goto send_data_out_error;
456 	}
457 	iser_dbg("data-out itt: %d, offset: %ld, sz: %ld\n",
458 		 itt, buf_offset, data_seg_len);
459 
460 
461 	err = iser_post_send(tx_desc);
462 	if (!err)
463 		return 0;
464 
465 send_data_out_error:
466 	iser_dto_buffs_release(send_dto);
467 	kmem_cache_free(ig.desc_cache, tx_desc);
468 	iser_err("conn %p failed err %d\n",conn, err);
469 	return err;
470 }
471 
472 int iser_send_control(struct iscsi_conn *conn,
473 		      struct iscsi_mgmt_task *mtask)
474 {
475 	struct iscsi_iser_conn *iser_conn = conn->dd_data;
476 	struct iser_desc *mdesc = mtask->dd_data;
477 	struct iser_dto *send_dto = NULL;
478 	unsigned long data_seg_len;
479 	int err = 0;
480 	struct iser_regd_buf *regd_buf;
481 	struct iser_device *device;
482 
483 	if (!iser_conn_state_comp(iser_conn->ib_conn, ISER_CONN_UP)) {
484 		iser_err("Failed to send, conn: 0x%p is not up\n", iser_conn->ib_conn);
485 		return -EPERM;
486 	}
487 
488 	if (iser_check_xmit(conn,mtask))
489 		return -ENOBUFS;
490 
491 	/* build the tx desc regd header and add it to the tx desc dto */
492 	mdesc->type = ISCSI_TX_CONTROL;
493 	send_dto = &mdesc->dto;
494 	send_dto->ctask = NULL;
495 	iser_create_send_desc(iser_conn, mdesc);
496 
497 	device = iser_conn->ib_conn->device;
498 
499 	iser_reg_single(device, send_dto->regd[0], DMA_TO_DEVICE);
500 
501 	data_seg_len = ntoh24(mtask->hdr->dlength);
502 
503 	if (data_seg_len > 0) {
504 		regd_buf = &mdesc->data_regd_buf;
505 		memset(regd_buf, 0, sizeof(struct iser_regd_buf));
506 		regd_buf->device = device;
507 		regd_buf->virt_addr = mtask->data;
508 		regd_buf->data_size = mtask->data_count;
509 		iser_reg_single(device, regd_buf,
510 				DMA_TO_DEVICE);
511 		iser_dto_add_regd_buff(send_dto, regd_buf,
512 				       0,
513 				       data_seg_len);
514 	}
515 
516 	if (iser_post_receive_control(conn) != 0) {
517 		iser_err("post_rcv_buff failed!\n");
518 		err = -ENOMEM;
519 		goto send_control_error;
520 	}
521 
522 	err = iser_post_send(mdesc);
523 	if (!err)
524 		return 0;
525 
526 send_control_error:
527 	iser_dto_buffs_release(send_dto);
528 	iser_err("conn %p failed err %d\n",conn, err);
529 	return err;
530 }
531 
532 /**
533  * iser_rcv_dto_completion - recv DTO completion
534  */
535 void iser_rcv_completion(struct iser_desc *rx_desc,
536 			 unsigned long dto_xfer_len)
537 {
538 	struct iser_dto        *dto = &rx_desc->dto;
539 	struct iscsi_iser_conn *conn = dto->ib_conn->iser_conn;
540 	struct iscsi_session *session = conn->iscsi_conn->session;
541 	struct iscsi_cmd_task *ctask;
542 	struct iscsi_iser_cmd_task *iser_ctask;
543 	struct iscsi_hdr *hdr;
544 	char   *rx_data = NULL;
545 	int     rx_data_len = 0;
546 	unsigned int itt;
547 	unsigned char opcode;
548 
549 	hdr = &rx_desc->iscsi_header;
550 
551 	iser_dbg("op 0x%x itt 0x%x\n", hdr->opcode,hdr->itt);
552 
553 	if (dto_xfer_len > ISER_TOTAL_HEADERS_LEN) { /* we have data */
554 		rx_data_len = dto_xfer_len - ISER_TOTAL_HEADERS_LEN;
555 		rx_data     = dto->regd[1]->virt_addr;
556 		rx_data    += dto->offset[1];
557 	}
558 
559 	opcode = hdr->opcode & ISCSI_OPCODE_MASK;
560 
561 	if (opcode == ISCSI_OP_SCSI_CMD_RSP) {
562 	        itt = get_itt(hdr->itt); /* mask out cid and age bits */
563 		if (!(itt < session->cmds_max))
564 			iser_err("itt can't be matched to task!!! "
565 				 "conn %p opcode %d cmds_max %d itt %d\n",
566 				 conn->iscsi_conn,opcode,session->cmds_max,itt);
567 		/* use the mapping given with the cmds array indexed by itt */
568 		ctask = (struct iscsi_cmd_task *)session->cmds[itt];
569 		iser_ctask = ctask->dd_data;
570 		iser_dbg("itt %d ctask %p\n",itt,ctask);
571 		iser_ctask->status = ISER_TASK_STATUS_COMPLETED;
572 		iser_ctask_rdma_finalize(iser_ctask);
573 	}
574 
575 	iser_dto_buffs_release(dto);
576 
577 	iscsi_iser_recv(conn->iscsi_conn, hdr, rx_data, rx_data_len);
578 
579 	kfree(rx_desc->data);
580 	kmem_cache_free(ig.desc_cache, rx_desc);
581 
582 	/* decrementing conn->post_recv_buf_count only --after-- freeing the   *
583 	 * task eliminates the need to worry on tasks which are completed in   *
584 	 * parallel to the execution of iser_conn_term. So the code that waits *
585 	 * for the posted rx bufs refcount to become zero handles everything   */
586 	atomic_dec(&conn->ib_conn->post_recv_buf_count);
587 }
588 
589 void iser_snd_completion(struct iser_desc *tx_desc)
590 {
591 	struct iser_dto        *dto = &tx_desc->dto;
592 	struct iser_conn       *ib_conn = dto->ib_conn;
593 	struct iscsi_iser_conn *iser_conn = ib_conn->iser_conn;
594 	struct iscsi_conn      *conn = iser_conn->iscsi_conn;
595 	struct iscsi_mgmt_task *mtask;
596 	int resume_tx = 0;
597 
598 	iser_dbg("Initiator, Data sent dto=0x%p\n", dto);
599 
600 	iser_dto_buffs_release(dto);
601 
602 	if (tx_desc->type == ISCSI_TX_DATAOUT)
603 		kmem_cache_free(ig.desc_cache, tx_desc);
604 
605 	if (atomic_read(&iser_conn->ib_conn->post_send_buf_count) ==
606 	    ISER_QP_MAX_REQ_DTOS)
607 		resume_tx = 1;
608 
609 	atomic_dec(&ib_conn->post_send_buf_count);
610 
611 	if (resume_tx) {
612 		iser_dbg("%ld resuming tx\n",jiffies);
613 		scsi_queue_work(conn->session->host, &conn->xmitwork);
614 	}
615 
616 	if (tx_desc->type == ISCSI_TX_CONTROL) {
617 		/* this arithmetic is legal by libiscsi dd_data allocation */
618 		mtask = (void *) ((long)(void *)tx_desc -
619 				  sizeof(struct iscsi_mgmt_task));
620 		if (mtask->hdr->itt == RESERVED_ITT) {
621 			struct iscsi_session *session = conn->session;
622 
623 			spin_lock(&conn->session->lock);
624 			iscsi_free_mgmt_task(conn, mtask);
625 			spin_unlock(&session->lock);
626 		}
627 	}
628 }
629 
630 void iser_ctask_rdma_init(struct iscsi_iser_cmd_task *iser_ctask)
631 
632 {
633 	iser_ctask->status = ISER_TASK_STATUS_INIT;
634 
635 	iser_ctask->dir[ISER_DIR_IN] = 0;
636 	iser_ctask->dir[ISER_DIR_OUT] = 0;
637 
638 	iser_ctask->data[ISER_DIR_IN].data_len  = 0;
639 	iser_ctask->data[ISER_DIR_OUT].data_len = 0;
640 
641 	memset(&iser_ctask->rdma_regd[ISER_DIR_IN], 0,
642 	       sizeof(struct iser_regd_buf));
643 	memset(&iser_ctask->rdma_regd[ISER_DIR_OUT], 0,
644 	       sizeof(struct iser_regd_buf));
645 }
646 
647 void iser_ctask_rdma_finalize(struct iscsi_iser_cmd_task *iser_ctask)
648 {
649 	int deferred;
650 	int is_rdma_aligned = 1;
651 	struct iser_regd_buf *regd;
652 
653 	/* if we were reading, copy back to unaligned sglist,
654 	 * anyway dma_unmap and free the copy
655 	 */
656 	if (iser_ctask->data_copy[ISER_DIR_IN].copy_buf != NULL) {
657 		is_rdma_aligned = 0;
658 		iser_finalize_rdma_unaligned_sg(iser_ctask, ISER_DIR_IN);
659 	}
660 	if (iser_ctask->data_copy[ISER_DIR_OUT].copy_buf != NULL) {
661 		is_rdma_aligned = 0;
662 		iser_finalize_rdma_unaligned_sg(iser_ctask, ISER_DIR_OUT);
663 	}
664 
665 	if (iser_ctask->dir[ISER_DIR_IN]) {
666 		regd = &iser_ctask->rdma_regd[ISER_DIR_IN];
667 		deferred = iser_regd_buff_release(regd);
668 		if (deferred) {
669 			iser_err("%d references remain for BUF-IN rdma reg\n",
670 				 atomic_read(&regd->ref_count));
671 		}
672 	}
673 
674 	if (iser_ctask->dir[ISER_DIR_OUT]) {
675 		regd = &iser_ctask->rdma_regd[ISER_DIR_OUT];
676 		deferred = iser_regd_buff_release(regd);
677 		if (deferred) {
678 			iser_err("%d references remain for BUF-OUT rdma reg\n",
679 				 atomic_read(&regd->ref_count));
680 		}
681 	}
682 
683        /* if the data was unaligned, it was already unmapped and then copied */
684        if (is_rdma_aligned)
685 		iser_dma_unmap_task_data(iser_ctask);
686 }
687 
688 void iser_dto_buffs_release(struct iser_dto *dto)
689 {
690 	int i;
691 
692 	for (i = 0; i < dto->regd_vector_len; i++)
693 		iser_regd_buff_release(dto->regd[i]);
694 }
695 
696