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_mem_reg *mem_reg;
53 	int err;
54 	struct iser_ctrl *hdr = &iser_task->desc.iser_header;
55 	struct iser_data_buf *buf_in = &iser_task->data[ISER_DIR_IN];
56 
57 	err = iser_dma_map_task_data(iser_task,
58 				     buf_in,
59 				     ISER_DIR_IN,
60 				     DMA_FROM_DEVICE);
61 	if (err)
62 		return err;
63 
64 	if (scsi_prot_sg_count(iser_task->sc)) {
65 		struct iser_data_buf *pbuf_in = &iser_task->prot[ISER_DIR_IN];
66 
67 		err = iser_dma_map_task_data(iser_task,
68 					     pbuf_in,
69 					     ISER_DIR_IN,
70 					     DMA_FROM_DEVICE);
71 		if (err)
72 			return err;
73 	}
74 
75 	err = iser_reg_rdma_mem(iser_task, ISER_DIR_IN, false);
76 	if (err) {
77 		iser_err("Failed to set up Data-IN RDMA\n");
78 		return err;
79 	}
80 	mem_reg = &iser_task->rdma_reg[ISER_DIR_IN];
81 
82 	hdr->flags    |= ISER_RSV;
83 	hdr->read_stag = cpu_to_be32(mem_reg->rkey);
84 	hdr->read_va   = cpu_to_be64(mem_reg->sge.addr);
85 
86 	iser_dbg("Cmd itt:%d READ tags RKEY:%#.4X VA:%#llX\n",
87 		 task->itt, mem_reg->rkey,
88 		 (unsigned long long)mem_reg->sge.addr);
89 
90 	return 0;
91 }
92 
93 /* Register user buffer memory and initialize passive rdma
94  *  dto descriptor. Data size is stored in
95  *  task->data[ISER_DIR_OUT].data_len, Protection size
96  *  is stored at task->prot[ISER_DIR_OUT].data_len
97  */
98 static int
99 iser_prepare_write_cmd(struct iscsi_task *task,
100 		       unsigned int imm_sz,
101 		       unsigned int unsol_sz,
102 		       unsigned int edtl)
103 {
104 	struct iscsi_iser_task *iser_task = task->dd_data;
105 	struct iser_mem_reg *mem_reg;
106 	int err;
107 	struct iser_ctrl *hdr = &iser_task->desc.iser_header;
108 	struct iser_data_buf *buf_out = &iser_task->data[ISER_DIR_OUT];
109 	struct ib_sge *tx_dsg = &iser_task->desc.tx_sg[1];
110 
111 	err = iser_dma_map_task_data(iser_task,
112 				     buf_out,
113 				     ISER_DIR_OUT,
114 				     DMA_TO_DEVICE);
115 	if (err)
116 		return err;
117 
118 	if (scsi_prot_sg_count(iser_task->sc)) {
119 		struct iser_data_buf *pbuf_out = &iser_task->prot[ISER_DIR_OUT];
120 
121 		err = iser_dma_map_task_data(iser_task,
122 					     pbuf_out,
123 					     ISER_DIR_OUT,
124 					     DMA_TO_DEVICE);
125 		if (err)
126 			return err;
127 	}
128 
129 	err = iser_reg_rdma_mem(iser_task, ISER_DIR_OUT,
130 				buf_out->data_len == imm_sz);
131 	if (err != 0) {
132 		iser_err("Failed to register write cmd RDMA mem\n");
133 		return err;
134 	}
135 
136 	mem_reg = &iser_task->rdma_reg[ISER_DIR_OUT];
137 
138 	if (unsol_sz < edtl) {
139 		hdr->flags     |= ISER_WSV;
140 		hdr->write_stag = cpu_to_be32(mem_reg->rkey);
141 		hdr->write_va   = cpu_to_be64(mem_reg->sge.addr + unsol_sz);
142 
143 		iser_dbg("Cmd itt:%d, WRITE tags, RKEY:%#.4X "
144 			 "VA:%#llX + unsol:%d\n",
145 			 task->itt, mem_reg->rkey,
146 			 (unsigned long long)mem_reg->sge.addr, unsol_sz);
147 	}
148 
149 	if (imm_sz > 0) {
150 		iser_dbg("Cmd itt:%d, WRITE, adding imm.data sz: %d\n",
151 			 task->itt, imm_sz);
152 		tx_dsg->addr = mem_reg->sge.addr;
153 		tx_dsg->length = imm_sz;
154 		tx_dsg->lkey = mem_reg->sge.lkey;
155 		iser_task->desc.num_sge = 2;
156 	}
157 
158 	return 0;
159 }
160 
161 /* creates a new tx descriptor and adds header regd buffer */
162 static void iser_create_send_desc(struct iser_conn	*iser_conn,
163 				  struct iser_tx_desc	*tx_desc)
164 {
165 	struct iser_device *device = iser_conn->ib_conn.device;
166 
167 	ib_dma_sync_single_for_cpu(device->ib_device,
168 		tx_desc->dma_addr, ISER_HEADERS_LEN, DMA_TO_DEVICE);
169 
170 	memset(&tx_desc->iser_header, 0, sizeof(struct iser_ctrl));
171 	tx_desc->iser_header.flags = ISER_VER;
172 	tx_desc->num_sge = 1;
173 }
174 
175 static void iser_free_login_buf(struct iser_conn *iser_conn)
176 {
177 	struct iser_device *device = iser_conn->ib_conn.device;
178 	struct iser_login_desc *desc = &iser_conn->login_desc;
179 
180 	if (!desc->req)
181 		return;
182 
183 	ib_dma_unmap_single(device->ib_device, desc->req_dma,
184 			    ISCSI_DEF_MAX_RECV_SEG_LEN, DMA_TO_DEVICE);
185 
186 	ib_dma_unmap_single(device->ib_device, desc->rsp_dma,
187 			    ISER_RX_LOGIN_SIZE, DMA_FROM_DEVICE);
188 
189 	kfree(desc->req);
190 	kfree(desc->rsp);
191 
192 	/* make sure we never redo any unmapping */
193 	desc->req = NULL;
194 	desc->rsp = NULL;
195 }
196 
197 static int iser_alloc_login_buf(struct iser_conn *iser_conn)
198 {
199 	struct iser_device *device = iser_conn->ib_conn.device;
200 	struct iser_login_desc *desc = &iser_conn->login_desc;
201 
202 	desc->req = kmalloc(ISCSI_DEF_MAX_RECV_SEG_LEN, GFP_KERNEL);
203 	if (!desc->req)
204 		return -ENOMEM;
205 
206 	desc->req_dma = ib_dma_map_single(device->ib_device, desc->req,
207 					  ISCSI_DEF_MAX_RECV_SEG_LEN,
208 					  DMA_TO_DEVICE);
209 	if (ib_dma_mapping_error(device->ib_device,
210 				desc->req_dma))
211 		goto free_req;
212 
213 	desc->rsp = kmalloc(ISER_RX_LOGIN_SIZE, GFP_KERNEL);
214 	if (!desc->rsp)
215 		goto unmap_req;
216 
217 	desc->rsp_dma = ib_dma_map_single(device->ib_device, desc->rsp,
218 					   ISER_RX_LOGIN_SIZE,
219 					   DMA_FROM_DEVICE);
220 	if (ib_dma_mapping_error(device->ib_device,
221 				desc->rsp_dma))
222 		goto free_rsp;
223 
224 	return 0;
225 
226 free_rsp:
227 	kfree(desc->rsp);
228 unmap_req:
229 	ib_dma_unmap_single(device->ib_device, desc->req_dma,
230 			    ISCSI_DEF_MAX_RECV_SEG_LEN,
231 			    DMA_TO_DEVICE);
232 free_req:
233 	kfree(desc->req);
234 
235 	return -ENOMEM;
236 }
237 
238 int iser_alloc_rx_descriptors(struct iser_conn *iser_conn,
239 			      struct iscsi_session *session)
240 {
241 	int i, j;
242 	u64 dma_addr;
243 	struct iser_rx_desc *rx_desc;
244 	struct ib_sge       *rx_sg;
245 	struct ib_conn *ib_conn = &iser_conn->ib_conn;
246 	struct iser_device *device = ib_conn->device;
247 
248 	iser_conn->qp_max_recv_dtos = session->cmds_max;
249 	iser_conn->qp_max_recv_dtos_mask = session->cmds_max - 1; /* cmds_max is 2^N */
250 	iser_conn->min_posted_rx = iser_conn->qp_max_recv_dtos >> 2;
251 
252 	if (device->reg_ops->alloc_reg_res(ib_conn, session->scsi_cmds_max,
253 					   iser_conn->scsi_sg_tablesize))
254 		goto create_rdma_reg_res_failed;
255 
256 	if (iser_alloc_login_buf(iser_conn))
257 		goto alloc_login_buf_fail;
258 
259 	iser_conn->num_rx_descs = session->cmds_max;
260 	iser_conn->rx_descs = kmalloc(iser_conn->num_rx_descs *
261 				sizeof(struct iser_rx_desc), GFP_KERNEL);
262 	if (!iser_conn->rx_descs)
263 		goto rx_desc_alloc_fail;
264 
265 	rx_desc = iser_conn->rx_descs;
266 
267 	for (i = 0; i < iser_conn->qp_max_recv_dtos; i++, rx_desc++)  {
268 		dma_addr = ib_dma_map_single(device->ib_device, (void *)rx_desc,
269 					ISER_RX_PAYLOAD_SIZE, DMA_FROM_DEVICE);
270 		if (ib_dma_mapping_error(device->ib_device, dma_addr))
271 			goto rx_desc_dma_map_failed;
272 
273 		rx_desc->dma_addr = dma_addr;
274 		rx_desc->cqe.done = iser_task_rsp;
275 		rx_sg = &rx_desc->rx_sg;
276 		rx_sg->addr = rx_desc->dma_addr;
277 		rx_sg->length = ISER_RX_PAYLOAD_SIZE;
278 		rx_sg->lkey = device->pd->local_dma_lkey;
279 	}
280 
281 	iser_conn->rx_desc_head = 0;
282 	return 0;
283 
284 rx_desc_dma_map_failed:
285 	rx_desc = iser_conn->rx_descs;
286 	for (j = 0; j < i; j++, rx_desc++)
287 		ib_dma_unmap_single(device->ib_device, rx_desc->dma_addr,
288 				    ISER_RX_PAYLOAD_SIZE, DMA_FROM_DEVICE);
289 	kfree(iser_conn->rx_descs);
290 	iser_conn->rx_descs = NULL;
291 rx_desc_alloc_fail:
292 	iser_free_login_buf(iser_conn);
293 alloc_login_buf_fail:
294 	device->reg_ops->free_reg_res(ib_conn);
295 create_rdma_reg_res_failed:
296 	iser_err("failed allocating rx descriptors / data buffers\n");
297 	return -ENOMEM;
298 }
299 
300 void iser_free_rx_descriptors(struct iser_conn *iser_conn)
301 {
302 	int i;
303 	struct iser_rx_desc *rx_desc;
304 	struct ib_conn *ib_conn = &iser_conn->ib_conn;
305 	struct iser_device *device = ib_conn->device;
306 
307 	if (device->reg_ops->free_reg_res)
308 		device->reg_ops->free_reg_res(ib_conn);
309 
310 	rx_desc = iser_conn->rx_descs;
311 	for (i = 0; i < iser_conn->qp_max_recv_dtos; i++, rx_desc++)
312 		ib_dma_unmap_single(device->ib_device, rx_desc->dma_addr,
313 				    ISER_RX_PAYLOAD_SIZE, DMA_FROM_DEVICE);
314 	kfree(iser_conn->rx_descs);
315 	/* make sure we never redo any unmapping */
316 	iser_conn->rx_descs = NULL;
317 
318 	iser_free_login_buf(iser_conn);
319 }
320 
321 static int iser_post_rx_bufs(struct iscsi_conn *conn, struct iscsi_hdr *req)
322 {
323 	struct iser_conn *iser_conn = conn->dd_data;
324 	struct ib_conn *ib_conn = &iser_conn->ib_conn;
325 	struct iscsi_session *session = conn->session;
326 
327 	iser_dbg("req op %x flags %x\n", req->opcode, req->flags);
328 	/* check if this is the last login - going to full feature phase */
329 	if ((req->flags & ISCSI_FULL_FEATURE_PHASE) != ISCSI_FULL_FEATURE_PHASE)
330 		return 0;
331 
332 	/*
333 	 * Check that there is one posted recv buffer
334 	 * (for the last login response).
335 	 */
336 	WARN_ON(ib_conn->post_recv_buf_count != 1);
337 
338 	if (session->discovery_sess) {
339 		iser_info("Discovery session, re-using login RX buffer\n");
340 		return 0;
341 	} else
342 		iser_info("Normal session, posting batch of RX %d buffers\n",
343 			  iser_conn->min_posted_rx);
344 
345 	/* Initial post receive buffers */
346 	if (iser_post_recvm(iser_conn, iser_conn->min_posted_rx))
347 		return -ENOMEM;
348 
349 	return 0;
350 }
351 
352 static inline bool iser_signal_comp(u8 sig_count)
353 {
354 	return ((sig_count % ISER_SIGNAL_CMD_COUNT) == 0);
355 }
356 
357 /**
358  * iser_send_command - send command PDU
359  */
360 int iser_send_command(struct iscsi_conn *conn,
361 		      struct iscsi_task *task)
362 {
363 	struct iser_conn *iser_conn = conn->dd_data;
364 	struct iscsi_iser_task *iser_task = task->dd_data;
365 	unsigned long edtl;
366 	int err;
367 	struct iser_data_buf *data_buf, *prot_buf;
368 	struct iscsi_scsi_req *hdr = (struct iscsi_scsi_req *)task->hdr;
369 	struct scsi_cmnd *sc  =  task->sc;
370 	struct iser_tx_desc *tx_desc = &iser_task->desc;
371 	u8 sig_count = ++iser_conn->ib_conn.sig_count;
372 
373 	edtl = ntohl(hdr->data_length);
374 
375 	/* build the tx desc regd header and add it to the tx desc dto */
376 	tx_desc->type = ISCSI_TX_SCSI_COMMAND;
377 	tx_desc->cqe.done = iser_cmd_comp;
378 	iser_create_send_desc(iser_conn, tx_desc);
379 
380 	if (hdr->flags & ISCSI_FLAG_CMD_READ) {
381 		data_buf = &iser_task->data[ISER_DIR_IN];
382 		prot_buf = &iser_task->prot[ISER_DIR_IN];
383 	} else {
384 		data_buf = &iser_task->data[ISER_DIR_OUT];
385 		prot_buf = &iser_task->prot[ISER_DIR_OUT];
386 	}
387 
388 	if (scsi_sg_count(sc)) { /* using a scatter list */
389 		data_buf->sg = scsi_sglist(sc);
390 		data_buf->size = scsi_sg_count(sc);
391 	}
392 	data_buf->data_len = scsi_bufflen(sc);
393 
394 	if (scsi_prot_sg_count(sc)) {
395 		prot_buf->sg  = scsi_prot_sglist(sc);
396 		prot_buf->size = scsi_prot_sg_count(sc);
397 		prot_buf->data_len = (data_buf->data_len >>
398 				     ilog2(sc->device->sector_size)) * 8;
399 	}
400 
401 	if (hdr->flags & ISCSI_FLAG_CMD_READ) {
402 		err = iser_prepare_read_cmd(task);
403 		if (err)
404 			goto send_command_error;
405 	}
406 	if (hdr->flags & ISCSI_FLAG_CMD_WRITE) {
407 		err = iser_prepare_write_cmd(task,
408 					     task->imm_count,
409 				             task->imm_count +
410 					     task->unsol_r2t.data_length,
411 					     edtl);
412 		if (err)
413 			goto send_command_error;
414 	}
415 
416 	iser_task->status = ISER_TASK_STATUS_STARTED;
417 
418 	err = iser_post_send(&iser_conn->ib_conn, tx_desc,
419 			     iser_signal_comp(sig_count));
420 	if (!err)
421 		return 0;
422 
423 send_command_error:
424 	iser_err("conn %p failed task->itt %d err %d\n",conn, task->itt, err);
425 	return err;
426 }
427 
428 /**
429  * iser_send_data_out - send data out PDU
430  */
431 int iser_send_data_out(struct iscsi_conn *conn,
432 		       struct iscsi_task *task,
433 		       struct iscsi_data *hdr)
434 {
435 	struct iser_conn *iser_conn = conn->dd_data;
436 	struct iscsi_iser_task *iser_task = task->dd_data;
437 	struct iser_tx_desc *tx_desc = NULL;
438 	struct iser_mem_reg *mem_reg;
439 	unsigned long buf_offset;
440 	unsigned long data_seg_len;
441 	uint32_t itt;
442 	int err;
443 	struct ib_sge *tx_dsg;
444 
445 	itt = (__force uint32_t)hdr->itt;
446 	data_seg_len = ntoh24(hdr->dlength);
447 	buf_offset   = ntohl(hdr->offset);
448 
449 	iser_dbg("%s itt %d dseg_len %d offset %d\n",
450 		 __func__,(int)itt,(int)data_seg_len,(int)buf_offset);
451 
452 	tx_desc = kmem_cache_zalloc(ig.desc_cache, GFP_ATOMIC);
453 	if (tx_desc == NULL) {
454 		iser_err("Failed to alloc desc for post dataout\n");
455 		return -ENOMEM;
456 	}
457 
458 	tx_desc->type = ISCSI_TX_DATAOUT;
459 	tx_desc->cqe.done = iser_dataout_comp;
460 	tx_desc->iser_header.flags = ISER_VER;
461 	memcpy(&tx_desc->iscsi_header, hdr, sizeof(struct iscsi_hdr));
462 
463 	/* build the tx desc */
464 	err = iser_initialize_task_headers(task, tx_desc);
465 	if (err)
466 		goto send_data_out_error;
467 
468 	mem_reg = &iser_task->rdma_reg[ISER_DIR_OUT];
469 	tx_dsg = &tx_desc->tx_sg[1];
470 	tx_dsg->addr = mem_reg->sge.addr + buf_offset;
471 	tx_dsg->length = data_seg_len;
472 	tx_dsg->lkey = mem_reg->sge.lkey;
473 	tx_desc->num_sge = 2;
474 
475 	if (buf_offset + data_seg_len > iser_task->data[ISER_DIR_OUT].data_len) {
476 		iser_err("Offset:%ld & DSL:%ld in Data-Out "
477 			 "inconsistent with total len:%ld, itt:%d\n",
478 			 buf_offset, data_seg_len,
479 			 iser_task->data[ISER_DIR_OUT].data_len, itt);
480 		err = -EINVAL;
481 		goto send_data_out_error;
482 	}
483 	iser_dbg("data-out itt: %d, offset: %ld, sz: %ld\n",
484 		 itt, buf_offset, data_seg_len);
485 
486 
487 	err = iser_post_send(&iser_conn->ib_conn, tx_desc, true);
488 	if (!err)
489 		return 0;
490 
491 send_data_out_error:
492 	kmem_cache_free(ig.desc_cache, tx_desc);
493 	iser_err("conn %p failed err %d\n", conn, err);
494 	return err;
495 }
496 
497 int iser_send_control(struct iscsi_conn *conn,
498 		      struct iscsi_task *task)
499 {
500 	struct iser_conn *iser_conn = conn->dd_data;
501 	struct iscsi_iser_task *iser_task = task->dd_data;
502 	struct iser_tx_desc *mdesc = &iser_task->desc;
503 	unsigned long data_seg_len;
504 	int err = 0;
505 	struct iser_device *device;
506 
507 	/* build the tx desc regd header and add it to the tx desc dto */
508 	mdesc->type = ISCSI_TX_CONTROL;
509 	mdesc->cqe.done = iser_ctrl_comp;
510 	iser_create_send_desc(iser_conn, mdesc);
511 
512 	device = iser_conn->ib_conn.device;
513 
514 	data_seg_len = ntoh24(task->hdr->dlength);
515 
516 	if (data_seg_len > 0) {
517 		struct iser_login_desc *desc = &iser_conn->login_desc;
518 		struct ib_sge *tx_dsg = &mdesc->tx_sg[1];
519 
520 		if (task != conn->login_task) {
521 			iser_err("data present on non login task!!!\n");
522 			goto send_control_error;
523 		}
524 
525 		ib_dma_sync_single_for_cpu(device->ib_device, desc->req_dma,
526 					   task->data_count, DMA_TO_DEVICE);
527 
528 		memcpy(desc->req, task->data, task->data_count);
529 
530 		ib_dma_sync_single_for_device(device->ib_device, desc->req_dma,
531 					      task->data_count, DMA_TO_DEVICE);
532 
533 		tx_dsg->addr = desc->req_dma;
534 		tx_dsg->length = task->data_count;
535 		tx_dsg->lkey = device->pd->local_dma_lkey;
536 		mdesc->num_sge = 2;
537 	}
538 
539 	if (task == conn->login_task) {
540 		iser_dbg("op %x dsl %lx, posting login rx buffer\n",
541 			 task->hdr->opcode, data_seg_len);
542 		err = iser_post_recvl(iser_conn);
543 		if (err)
544 			goto send_control_error;
545 		err = iser_post_rx_bufs(conn, task->hdr);
546 		if (err)
547 			goto send_control_error;
548 	}
549 
550 	err = iser_post_send(&iser_conn->ib_conn, mdesc, true);
551 	if (!err)
552 		return 0;
553 
554 send_control_error:
555 	iser_err("conn %p failed err %d\n",conn, err);
556 	return err;
557 }
558 
559 void iser_login_rsp(struct ib_cq *cq, struct ib_wc *wc)
560 {
561 	struct ib_conn *ib_conn = wc->qp->qp_context;
562 	struct iser_conn *iser_conn = to_iser_conn(ib_conn);
563 	struct iser_login_desc *desc = iser_login(wc->wr_cqe);
564 	struct iscsi_hdr *hdr;
565 	char *data;
566 	int length;
567 
568 	if (unlikely(wc->status != IB_WC_SUCCESS)) {
569 		iser_err_comp(wc, "login_rsp");
570 		return;
571 	}
572 
573 	ib_dma_sync_single_for_cpu(ib_conn->device->ib_device,
574 				   desc->rsp_dma, ISER_RX_LOGIN_SIZE,
575 				   DMA_FROM_DEVICE);
576 
577 	hdr = desc->rsp + sizeof(struct iser_ctrl);
578 	data = desc->rsp + ISER_HEADERS_LEN;
579 	length = wc->byte_len - ISER_HEADERS_LEN;
580 
581 	iser_dbg("op 0x%x itt 0x%x dlen %d\n", hdr->opcode,
582 		 hdr->itt, length);
583 
584 	iscsi_iser_recv(iser_conn->iscsi_conn, hdr, data, length);
585 
586 	ib_dma_sync_single_for_device(ib_conn->device->ib_device,
587 				      desc->rsp_dma, ISER_RX_LOGIN_SIZE,
588 				      DMA_FROM_DEVICE);
589 
590 	ib_conn->post_recv_buf_count--;
591 }
592 
593 static inline void
594 iser_inv_desc(struct iser_fr_desc *desc, u32 rkey)
595 {
596 	if (likely(rkey == desc->rsc.mr->rkey))
597 		desc->rsc.mr_valid = 0;
598 	else if (likely(rkey == desc->pi_ctx->sig_mr->rkey))
599 		desc->pi_ctx->sig_mr_valid = 0;
600 }
601 
602 static int
603 iser_check_remote_inv(struct iser_conn *iser_conn,
604 		      struct ib_wc *wc,
605 		      struct iscsi_hdr *hdr)
606 {
607 	if (wc->wc_flags & IB_WC_WITH_INVALIDATE) {
608 		struct iscsi_task *task;
609 		u32 rkey = wc->ex.invalidate_rkey;
610 
611 		iser_dbg("conn %p: remote invalidation for rkey %#x\n",
612 			 iser_conn, rkey);
613 
614 		if (unlikely(!iser_conn->snd_w_inv)) {
615 			iser_err("conn %p: unexepected remote invalidation, "
616 				 "terminating connection\n", iser_conn);
617 			return -EPROTO;
618 		}
619 
620 		task = iscsi_itt_to_ctask(iser_conn->iscsi_conn, hdr->itt);
621 		if (likely(task)) {
622 			struct iscsi_iser_task *iser_task = task->dd_data;
623 			struct iser_fr_desc *desc;
624 
625 			if (iser_task->dir[ISER_DIR_IN]) {
626 				desc = iser_task->rdma_reg[ISER_DIR_IN].mem_h;
627 				iser_inv_desc(desc, rkey);
628 			}
629 
630 			if (iser_task->dir[ISER_DIR_OUT]) {
631 				desc = iser_task->rdma_reg[ISER_DIR_OUT].mem_h;
632 				iser_inv_desc(desc, rkey);
633 			}
634 		} else {
635 			iser_err("failed to get task for itt=%d\n", hdr->itt);
636 			return -EINVAL;
637 		}
638 	}
639 
640 	return 0;
641 }
642 
643 
644 void iser_task_rsp(struct ib_cq *cq, struct ib_wc *wc)
645 {
646 	struct ib_conn *ib_conn = wc->qp->qp_context;
647 	struct iser_conn *iser_conn = to_iser_conn(ib_conn);
648 	struct iser_rx_desc *desc = iser_rx(wc->wr_cqe);
649 	struct iscsi_hdr *hdr;
650 	int length;
651 	int outstanding, count, err;
652 
653 	if (unlikely(wc->status != IB_WC_SUCCESS)) {
654 		iser_err_comp(wc, "task_rsp");
655 		return;
656 	}
657 
658 	ib_dma_sync_single_for_cpu(ib_conn->device->ib_device,
659 				   desc->dma_addr, ISER_RX_PAYLOAD_SIZE,
660 				   DMA_FROM_DEVICE);
661 
662 	hdr = &desc->iscsi_header;
663 	length = wc->byte_len - ISER_HEADERS_LEN;
664 
665 	iser_dbg("op 0x%x itt 0x%x dlen %d\n", hdr->opcode,
666 		 hdr->itt, length);
667 
668 	if (iser_check_remote_inv(iser_conn, wc, hdr)) {
669 		iscsi_conn_failure(iser_conn->iscsi_conn,
670 				   ISCSI_ERR_CONN_FAILED);
671 		return;
672 	}
673 
674 	iscsi_iser_recv(iser_conn->iscsi_conn, hdr, desc->data, length);
675 
676 	ib_dma_sync_single_for_device(ib_conn->device->ib_device,
677 				      desc->dma_addr, ISER_RX_PAYLOAD_SIZE,
678 				      DMA_FROM_DEVICE);
679 
680 	/* decrementing conn->post_recv_buf_count only --after-- freeing the   *
681 	 * task eliminates the need to worry on tasks which are completed in   *
682 	 * parallel to the execution of iser_conn_term. So the code that waits *
683 	 * for the posted rx bufs refcount to become zero handles everything   */
684 	ib_conn->post_recv_buf_count--;
685 
686 	outstanding = ib_conn->post_recv_buf_count;
687 	if (outstanding + iser_conn->min_posted_rx <= iser_conn->qp_max_recv_dtos) {
688 		count = min(iser_conn->qp_max_recv_dtos - outstanding,
689 			    iser_conn->min_posted_rx);
690 		err = iser_post_recvm(iser_conn, count);
691 		if (err)
692 			iser_err("posting %d rx bufs err %d\n", count, err);
693 	}
694 }
695 
696 void iser_cmd_comp(struct ib_cq *cq, struct ib_wc *wc)
697 {
698 	if (unlikely(wc->status != IB_WC_SUCCESS))
699 		iser_err_comp(wc, "command");
700 }
701 
702 void iser_ctrl_comp(struct ib_cq *cq, struct ib_wc *wc)
703 {
704 	struct iser_tx_desc *desc = iser_tx(wc->wr_cqe);
705 	struct iscsi_task *task;
706 
707 	if (unlikely(wc->status != IB_WC_SUCCESS)) {
708 		iser_err_comp(wc, "control");
709 		return;
710 	}
711 
712 	/* this arithmetic is legal by libiscsi dd_data allocation */
713 	task = (void *)desc - sizeof(struct iscsi_task);
714 	if (task->hdr->itt == RESERVED_ITT)
715 		iscsi_put_task(task);
716 }
717 
718 void iser_dataout_comp(struct ib_cq *cq, struct ib_wc *wc)
719 {
720 	struct iser_tx_desc *desc = iser_tx(wc->wr_cqe);
721 	struct ib_conn *ib_conn = wc->qp->qp_context;
722 	struct iser_device *device = ib_conn->device;
723 
724 	if (unlikely(wc->status != IB_WC_SUCCESS))
725 		iser_err_comp(wc, "dataout");
726 
727 	ib_dma_unmap_single(device->ib_device, desc->dma_addr,
728 			    ISER_HEADERS_LEN, DMA_TO_DEVICE);
729 	kmem_cache_free(ig.desc_cache, desc);
730 }
731 
732 void iser_task_rdma_init(struct iscsi_iser_task *iser_task)
733 
734 {
735 	iser_task->status = ISER_TASK_STATUS_INIT;
736 
737 	iser_task->dir[ISER_DIR_IN] = 0;
738 	iser_task->dir[ISER_DIR_OUT] = 0;
739 
740 	iser_task->data[ISER_DIR_IN].data_len  = 0;
741 	iser_task->data[ISER_DIR_OUT].data_len = 0;
742 
743 	iser_task->prot[ISER_DIR_IN].data_len  = 0;
744 	iser_task->prot[ISER_DIR_OUT].data_len = 0;
745 
746 	memset(&iser_task->rdma_reg[ISER_DIR_IN], 0,
747 	       sizeof(struct iser_mem_reg));
748 	memset(&iser_task->rdma_reg[ISER_DIR_OUT], 0,
749 	       sizeof(struct iser_mem_reg));
750 }
751 
752 void iser_task_rdma_finalize(struct iscsi_iser_task *iser_task)
753 {
754 	int prot_count = scsi_prot_sg_count(iser_task->sc);
755 
756 	if (iser_task->dir[ISER_DIR_IN]) {
757 		iser_unreg_rdma_mem(iser_task, ISER_DIR_IN);
758 		iser_dma_unmap_task_data(iser_task,
759 					 &iser_task->data[ISER_DIR_IN],
760 					 DMA_FROM_DEVICE);
761 		if (prot_count)
762 			iser_dma_unmap_task_data(iser_task,
763 						 &iser_task->prot[ISER_DIR_IN],
764 						 DMA_FROM_DEVICE);
765 	}
766 
767 	if (iser_task->dir[ISER_DIR_OUT]) {
768 		iser_unreg_rdma_mem(iser_task, ISER_DIR_OUT);
769 		iser_dma_unmap_task_data(iser_task,
770 					 &iser_task->data[ISER_DIR_OUT],
771 					 DMA_TO_DEVICE);
772 		if (prot_count)
773 			iser_dma_unmap_task_data(iser_task,
774 						 &iser_task->prot[ISER_DIR_OUT],
775 						 DMA_TO_DEVICE);
776 	}
777 }
778