xref: /openbmc/linux/drivers/target/tcm_fc/tfc_cmd.c (revision 51550985)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (c) 2010 Cisco Systems, Inc.
4  */
5 
6 /* XXX TBD some includes may be extraneous */
7 
8 #include <linux/module.h>
9 #include <linux/moduleparam.h>
10 #include <linux/utsname.h>
11 #include <linux/init.h>
12 #include <linux/slab.h>
13 #include <linux/kthread.h>
14 #include <linux/types.h>
15 #include <linux/string.h>
16 #include <linux/configfs.h>
17 #include <linux/ctype.h>
18 #include <linux/hash.h>
19 #include <asm/unaligned.h>
20 #include <scsi/scsi_tcq.h>
21 #include <scsi/libfc.h>
22 
23 #include <target/target_core_base.h>
24 #include <target/target_core_fabric.h>
25 
26 #include "tcm_fc.h"
27 
28 /*
29  * Dump cmd state for debugging.
30  */
_ft_dump_cmd(struct ft_cmd * cmd,const char * caller)31 static void _ft_dump_cmd(struct ft_cmd *cmd, const char *caller)
32 {
33 	struct fc_exch *ep;
34 	struct fc_seq *sp;
35 	struct se_cmd *se_cmd;
36 	struct scatterlist *sg;
37 	int count;
38 
39 	se_cmd = &cmd->se_cmd;
40 	pr_debug("%s: cmd %p sess %p seq %p se_cmd %p\n",
41 		caller, cmd, cmd->sess, cmd->seq, se_cmd);
42 
43 	pr_debug("%s: cmd %p data_nents %u len %u se_cmd_flags <0x%x>\n",
44 		caller, cmd, se_cmd->t_data_nents,
45 	       se_cmd->data_length, se_cmd->se_cmd_flags);
46 
47 	for_each_sg(se_cmd->t_data_sg, sg, se_cmd->t_data_nents, count)
48 		pr_debug("%s: cmd %p sg %p page %p "
49 			"len 0x%x off 0x%x\n",
50 			caller, cmd, sg,
51 			sg_page(sg), sg->length, sg->offset);
52 
53 	sp = cmd->seq;
54 	if (sp) {
55 		ep = fc_seq_exch(sp);
56 		pr_debug("%s: cmd %p sid %x did %x "
57 			"ox_id %x rx_id %x seq_id %x e_stat %x\n",
58 			caller, cmd, ep->sid, ep->did, ep->oxid, ep->rxid,
59 			sp->id, ep->esb_stat);
60 	}
61 }
62 
ft_dump_cmd(struct ft_cmd * cmd,const char * caller)63 void ft_dump_cmd(struct ft_cmd *cmd, const char *caller)
64 {
65 	if (unlikely(ft_debug_logging))
66 		_ft_dump_cmd(cmd, caller);
67 }
68 
ft_free_cmd(struct ft_cmd * cmd)69 static void ft_free_cmd(struct ft_cmd *cmd)
70 {
71 	struct fc_frame *fp;
72 	struct ft_sess *sess;
73 
74 	if (!cmd)
75 		return;
76 	sess = cmd->sess;
77 	fp = cmd->req_frame;
78 	if (fr_seq(fp))
79 		fc_seq_release(fr_seq(fp));
80 	fc_frame_free(fp);
81 	target_free_tag(sess->se_sess, &cmd->se_cmd);
82 	ft_sess_put(sess);	/* undo get from lookup at recv */
83 }
84 
ft_release_cmd(struct se_cmd * se_cmd)85 void ft_release_cmd(struct se_cmd *se_cmd)
86 {
87 	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
88 
89 	ft_free_cmd(cmd);
90 }
91 
ft_check_stop_free(struct se_cmd * se_cmd)92 int ft_check_stop_free(struct se_cmd *se_cmd)
93 {
94 	return transport_generic_free_cmd(se_cmd, 0);
95 }
96 
97 /*
98  * Send response.
99  */
ft_queue_status(struct se_cmd * se_cmd)100 int ft_queue_status(struct se_cmd *se_cmd)
101 {
102 	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
103 	struct fc_frame *fp;
104 	struct fcp_resp_with_ext *fcp;
105 	struct fc_lport *lport;
106 	struct fc_exch *ep;
107 	size_t len;
108 	int rc;
109 
110 	if (cmd->aborted)
111 		return 0;
112 	ft_dump_cmd(cmd, __func__);
113 	ep = fc_seq_exch(cmd->seq);
114 	lport = ep->lp;
115 	len = sizeof(*fcp) + se_cmd->scsi_sense_length;
116 	fp = fc_frame_alloc(lport, len);
117 	if (!fp) {
118 		se_cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
119 		return -ENOMEM;
120 	}
121 
122 	fcp = fc_frame_payload_get(fp, len);
123 	memset(fcp, 0, len);
124 	fcp->resp.fr_status = se_cmd->scsi_status;
125 
126 	len = se_cmd->scsi_sense_length;
127 	if (len) {
128 		fcp->resp.fr_flags |= FCP_SNS_LEN_VAL;
129 		fcp->ext.fr_sns_len = htonl(len);
130 		memcpy((fcp + 1), se_cmd->sense_buffer, len);
131 	}
132 
133 	/*
134 	 * Test underflow and overflow with one mask.  Usually both are off.
135 	 * Bidirectional commands are not handled yet.
136 	 */
137 	if (se_cmd->se_cmd_flags & (SCF_OVERFLOW_BIT | SCF_UNDERFLOW_BIT)) {
138 		if (se_cmd->se_cmd_flags & SCF_OVERFLOW_BIT)
139 			fcp->resp.fr_flags |= FCP_RESID_OVER;
140 		else
141 			fcp->resp.fr_flags |= FCP_RESID_UNDER;
142 		fcp->ext.fr_resid = cpu_to_be32(se_cmd->residual_count);
143 	}
144 
145 	/*
146 	 * Send response.
147 	 */
148 	cmd->seq = fc_seq_start_next(cmd->seq);
149 	fc_fill_fc_hdr(fp, FC_RCTL_DD_CMD_STATUS, ep->did, ep->sid, FC_TYPE_FCP,
150 		       FC_FC_EX_CTX | FC_FC_LAST_SEQ | FC_FC_END_SEQ, 0);
151 
152 	rc = fc_seq_send(lport, cmd->seq, fp);
153 	if (rc) {
154 		pr_info_ratelimited("%s: Failed to send response frame %p, "
155 				    "xid <0x%x>\n", __func__, fp, ep->xid);
156 		/*
157 		 * Generate a TASK_SET_FULL status to notify the initiator
158 		 * to reduce it's queue_depth after the se_cmd response has
159 		 * been re-queued by target-core.
160 		 */
161 		se_cmd->scsi_status = SAM_STAT_TASK_SET_FULL;
162 		return -ENOMEM;
163 	}
164 	fc_exch_done(cmd->seq);
165 	/*
166 	 * Drop the extra ACK_KREF reference taken by target_submit_cmd()
167 	 * ahead of ft_check_stop_free() -> transport_generic_free_cmd()
168 	 * final se_cmd->cmd_kref put.
169 	 */
170 	target_put_sess_cmd(&cmd->se_cmd);
171 	return 0;
172 }
173 
174 /*
175  * Send TX_RDY (transfer ready).
176  */
ft_write_pending(struct se_cmd * se_cmd)177 int ft_write_pending(struct se_cmd *se_cmd)
178 {
179 	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
180 	struct fc_frame *fp;
181 	struct fcp_txrdy *txrdy;
182 	struct fc_lport *lport;
183 	struct fc_exch *ep;
184 	struct fc_frame_header *fh;
185 	u32 f_ctl;
186 
187 	ft_dump_cmd(cmd, __func__);
188 
189 	if (cmd->aborted)
190 		return 0;
191 	ep = fc_seq_exch(cmd->seq);
192 	lport = ep->lp;
193 	fp = fc_frame_alloc(lport, sizeof(*txrdy));
194 	if (!fp)
195 		return -ENOMEM; /* Signal QUEUE_FULL */
196 
197 	txrdy = fc_frame_payload_get(fp, sizeof(*txrdy));
198 	memset(txrdy, 0, sizeof(*txrdy));
199 	txrdy->ft_burst_len = htonl(se_cmd->data_length);
200 
201 	cmd->seq = fc_seq_start_next(cmd->seq);
202 	fc_fill_fc_hdr(fp, FC_RCTL_DD_DATA_DESC, ep->did, ep->sid, FC_TYPE_FCP,
203 		       FC_FC_EX_CTX | FC_FC_END_SEQ | FC_FC_SEQ_INIT, 0);
204 
205 	fh = fc_frame_header_get(fp);
206 	f_ctl = ntoh24(fh->fh_f_ctl);
207 
208 	/* Only if it is 'Exchange Responder' */
209 	if (f_ctl & FC_FC_EX_CTX) {
210 		/* Target is 'exchange responder' and sending XFER_READY
211 		 * to 'exchange initiator (initiator)'
212 		 */
213 		if ((ep->xid <= lport->lro_xid) &&
214 		    (fh->fh_r_ctl == FC_RCTL_DD_DATA_DESC)) {
215 			if ((se_cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) &&
216 			    lport->tt.ddp_target(lport, ep->xid,
217 						 se_cmd->t_data_sg,
218 						 se_cmd->t_data_nents))
219 				cmd->was_ddp_setup = 1;
220 		}
221 	}
222 	fc_seq_send(lport, cmd->seq, fp);
223 	return 0;
224 }
225 
226 /*
227  * FC sequence response handler for follow-on sequences (data) and aborts.
228  */
ft_recv_seq(struct fc_seq * sp,struct fc_frame * fp,void * arg)229 static void ft_recv_seq(struct fc_seq *sp, struct fc_frame *fp, void *arg)
230 {
231 	struct ft_cmd *cmd = arg;
232 	struct fc_frame_header *fh;
233 
234 	if (IS_ERR(fp)) {
235 		/* XXX need to find cmd if queued */
236 		cmd->seq = NULL;
237 		cmd->aborted = true;
238 		return;
239 	}
240 
241 	fh = fc_frame_header_get(fp);
242 
243 	switch (fh->fh_r_ctl) {
244 	case FC_RCTL_DD_SOL_DATA:	/* write data */
245 		ft_recv_write_data(cmd, fp);
246 		break;
247 	case FC_RCTL_DD_UNSOL_CTL:	/* command */
248 	case FC_RCTL_DD_SOL_CTL:	/* transfer ready */
249 	case FC_RCTL_DD_DATA_DESC:	/* transfer ready */
250 	default:
251 		pr_debug("%s: unhandled frame r_ctl %x\n",
252 		       __func__, fh->fh_r_ctl);
253 		ft_invl_hw_context(cmd);
254 		fc_frame_free(fp);
255 		transport_generic_free_cmd(&cmd->se_cmd, 0);
256 		break;
257 	}
258 }
259 
260 /*
261  * Send a FCP response including SCSI status and optional FCP rsp_code.
262  * status is SAM_STAT_GOOD (zero) iff code is valid.
263  * This is used in error cases, such as allocation failures.
264  */
ft_send_resp_status(struct fc_lport * lport,const struct fc_frame * rx_fp,u32 status,enum fcp_resp_rsp_codes code)265 static void ft_send_resp_status(struct fc_lport *lport,
266 				const struct fc_frame *rx_fp,
267 				u32 status, enum fcp_resp_rsp_codes code)
268 {
269 	struct fc_frame *fp;
270 	struct fc_seq *sp;
271 	const struct fc_frame_header *fh;
272 	size_t len;
273 	struct fcp_resp_with_ext *fcp;
274 	struct fcp_resp_rsp_info *info;
275 
276 	fh = fc_frame_header_get(rx_fp);
277 	pr_debug("FCP error response: did %x oxid %x status %x code %x\n",
278 		  ntoh24(fh->fh_s_id), ntohs(fh->fh_ox_id), status, code);
279 	len = sizeof(*fcp);
280 	if (status == SAM_STAT_GOOD)
281 		len += sizeof(*info);
282 	fp = fc_frame_alloc(lport, len);
283 	if (!fp)
284 		return;
285 	fcp = fc_frame_payload_get(fp, len);
286 	memset(fcp, 0, len);
287 	fcp->resp.fr_status = status;
288 	if (status == SAM_STAT_GOOD) {
289 		fcp->ext.fr_rsp_len = htonl(sizeof(*info));
290 		fcp->resp.fr_flags |= FCP_RSP_LEN_VAL;
291 		info = (struct fcp_resp_rsp_info *)(fcp + 1);
292 		info->rsp_code = code;
293 	}
294 
295 	fc_fill_reply_hdr(fp, rx_fp, FC_RCTL_DD_CMD_STATUS, 0);
296 	sp = fr_seq(fp);
297 	if (sp) {
298 		fc_seq_send(lport, sp, fp);
299 		fc_exch_done(sp);
300 	} else {
301 		lport->tt.frame_send(lport, fp);
302 	}
303 }
304 
305 /*
306  * Send error or task management response.
307  */
ft_send_resp_code(struct ft_cmd * cmd,enum fcp_resp_rsp_codes code)308 static void ft_send_resp_code(struct ft_cmd *cmd,
309 			      enum fcp_resp_rsp_codes code)
310 {
311 	ft_send_resp_status(cmd->sess->tport->lport,
312 			    cmd->req_frame, SAM_STAT_GOOD, code);
313 }
314 
315 
316 /*
317  * Send error or task management response.
318  * Always frees the cmd and associated state.
319  */
ft_send_resp_code_and_free(struct ft_cmd * cmd,enum fcp_resp_rsp_codes code)320 static void ft_send_resp_code_and_free(struct ft_cmd *cmd,
321 				      enum fcp_resp_rsp_codes code)
322 {
323 	ft_send_resp_code(cmd, code);
324 	ft_free_cmd(cmd);
325 }
326 
327 /*
328  * Handle Task Management Request.
329  */
ft_send_tm(struct ft_cmd * cmd)330 static void ft_send_tm(struct ft_cmd *cmd)
331 {
332 	struct fcp_cmnd *fcp;
333 	int rc;
334 	u8 tm_func;
335 
336 	fcp = fc_frame_payload_get(cmd->req_frame, sizeof(*fcp));
337 
338 	switch (fcp->fc_tm_flags) {
339 	case FCP_TMF_LUN_RESET:
340 		tm_func = TMR_LUN_RESET;
341 		break;
342 	case FCP_TMF_TGT_RESET:
343 		tm_func = TMR_TARGET_WARM_RESET;
344 		break;
345 	case FCP_TMF_CLR_TASK_SET:
346 		tm_func = TMR_CLEAR_TASK_SET;
347 		break;
348 	case FCP_TMF_ABT_TASK_SET:
349 		tm_func = TMR_ABORT_TASK_SET;
350 		break;
351 	case FCP_TMF_CLR_ACA:
352 		tm_func = TMR_CLEAR_ACA;
353 		break;
354 	default:
355 		/*
356 		 * FCP4r01 indicates having a combination of
357 		 * tm_flags set is invalid.
358 		 */
359 		pr_debug("invalid FCP tm_flags %x\n", fcp->fc_tm_flags);
360 		ft_send_resp_code_and_free(cmd, FCP_CMND_FIELDS_INVALID);
361 		return;
362 	}
363 
364 	/* FIXME: Add referenced task tag for ABORT_TASK */
365 	rc = target_submit_tmr(&cmd->se_cmd, cmd->sess->se_sess,
366 		&cmd->ft_sense_buffer[0], scsilun_to_int(&fcp->fc_lun),
367 		cmd, tm_func, GFP_KERNEL, 0, TARGET_SCF_ACK_KREF);
368 	if (rc < 0)
369 		ft_send_resp_code_and_free(cmd, FCP_TMF_FAILED);
370 }
371 
372 /*
373  * Send status from completed task management request.
374  */
ft_queue_tm_resp(struct se_cmd * se_cmd)375 void ft_queue_tm_resp(struct se_cmd *se_cmd)
376 {
377 	struct ft_cmd *cmd = container_of(se_cmd, struct ft_cmd, se_cmd);
378 	struct se_tmr_req *tmr = se_cmd->se_tmr_req;
379 	enum fcp_resp_rsp_codes code;
380 
381 	if (cmd->aborted)
382 		return;
383 	switch (tmr->response) {
384 	case TMR_FUNCTION_COMPLETE:
385 		code = FCP_TMF_CMPL;
386 		break;
387 	case TMR_LUN_DOES_NOT_EXIST:
388 		code = FCP_TMF_INVALID_LUN;
389 		break;
390 	case TMR_FUNCTION_REJECTED:
391 		code = FCP_TMF_REJECTED;
392 		break;
393 	case TMR_TASK_DOES_NOT_EXIST:
394 	case TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED:
395 	default:
396 		code = FCP_TMF_FAILED;
397 		break;
398 	}
399 	pr_debug("tmr fn %d resp %d fcp code %d\n",
400 		  tmr->function, tmr->response, code);
401 	ft_send_resp_code(cmd, code);
402 	/*
403 	 * Drop the extra ACK_KREF reference taken by target_submit_tmr()
404 	 * ahead of ft_check_stop_free() -> transport_generic_free_cmd()
405 	 * final se_cmd->cmd_kref put.
406 	 */
407 	target_put_sess_cmd(&cmd->se_cmd);
408 }
409 
ft_aborted_task(struct se_cmd * se_cmd)410 void ft_aborted_task(struct se_cmd *se_cmd)
411 {
412 	return;
413 }
414 
415 static void ft_send_work(struct work_struct *work);
416 
417 /*
418  * Handle incoming FCP command.
419  */
ft_recv_cmd(struct ft_sess * sess,struct fc_frame * fp)420 static void ft_recv_cmd(struct ft_sess *sess, struct fc_frame *fp)
421 {
422 	struct ft_cmd *cmd;
423 	struct fc_lport *lport = sess->tport->lport;
424 	struct se_session *se_sess = sess->se_sess;
425 	int tag, cpu;
426 
427 	tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);
428 	if (tag < 0)
429 		goto busy;
430 
431 	cmd = &((struct ft_cmd *)se_sess->sess_cmd_map)[tag];
432 	memset(cmd, 0, sizeof(struct ft_cmd));
433 
434 	cmd->se_cmd.map_tag = tag;
435 	cmd->se_cmd.map_cpu = cpu;
436 	cmd->sess = sess;
437 	cmd->seq = fc_seq_assign(lport, fp);
438 	if (!cmd->seq) {
439 		target_free_tag(se_sess, &cmd->se_cmd);
440 		goto busy;
441 	}
442 	cmd->req_frame = fp;		/* hold frame during cmd */
443 
444 	INIT_WORK(&cmd->work, ft_send_work);
445 	queue_work(sess->tport->tpg->workqueue, &cmd->work);
446 	return;
447 
448 busy:
449 	pr_debug("cmd or seq allocation failure - sending BUSY\n");
450 	ft_send_resp_status(lport, fp, SAM_STAT_BUSY, 0);
451 	fc_frame_free(fp);
452 	ft_sess_put(sess);		/* undo get from lookup */
453 }
454 
455 
456 /*
457  * Handle incoming FCP frame.
458  * Caller has verified that the frame is type FCP.
459  */
ft_recv_req(struct ft_sess * sess,struct fc_frame * fp)460 void ft_recv_req(struct ft_sess *sess, struct fc_frame *fp)
461 {
462 	struct fc_frame_header *fh = fc_frame_header_get(fp);
463 
464 	switch (fh->fh_r_ctl) {
465 	case FC_RCTL_DD_UNSOL_CMD:	/* command */
466 		ft_recv_cmd(sess, fp);
467 		break;
468 	case FC_RCTL_DD_SOL_DATA:	/* write data */
469 	case FC_RCTL_DD_UNSOL_CTL:
470 	case FC_RCTL_DD_SOL_CTL:
471 	case FC_RCTL_DD_DATA_DESC:	/* transfer ready */
472 	case FC_RCTL_ELS4_REQ:		/* SRR, perhaps */
473 	default:
474 		pr_debug("%s: unhandled frame r_ctl %x\n",
475 		       __func__, fh->fh_r_ctl);
476 		fc_frame_free(fp);
477 		ft_sess_put(sess);	/* undo get from lookup */
478 		break;
479 	}
480 }
481 
482 /*
483  * Send new command to target.
484  */
ft_send_work(struct work_struct * work)485 static void ft_send_work(struct work_struct *work)
486 {
487 	struct ft_cmd *cmd = container_of(work, struct ft_cmd, work);
488 	struct fc_frame_header *fh = fc_frame_header_get(cmd->req_frame);
489 	struct fcp_cmnd *fcp;
490 	int data_dir = 0;
491 	int task_attr;
492 
493 	fcp = fc_frame_payload_get(cmd->req_frame, sizeof(*fcp));
494 	if (!fcp)
495 		goto err;
496 
497 	if (fcp->fc_flags & FCP_CFL_LEN_MASK)
498 		goto err;		/* not handling longer CDBs yet */
499 
500 	/*
501 	 * Check for FCP task management flags
502 	 */
503 	if (fcp->fc_tm_flags) {
504 		ft_send_tm(cmd);
505 		return;
506 	}
507 
508 	switch (fcp->fc_flags & (FCP_CFL_RDDATA | FCP_CFL_WRDATA)) {
509 	case 0:
510 		data_dir = DMA_NONE;
511 		break;
512 	case FCP_CFL_RDDATA:
513 		data_dir = DMA_FROM_DEVICE;
514 		break;
515 	case FCP_CFL_WRDATA:
516 		data_dir = DMA_TO_DEVICE;
517 		break;
518 	case FCP_CFL_WRDATA | FCP_CFL_RDDATA:
519 		goto err;	/* TBD not supported by tcm_fc yet */
520 	}
521 	/*
522 	 * Locate the SAM Task Attr from fc_pri_ta
523 	 */
524 	switch (fcp->fc_pri_ta & FCP_PTA_MASK) {
525 	case FCP_PTA_HEADQ:
526 		task_attr = TCM_HEAD_TAG;
527 		break;
528 	case FCP_PTA_ORDERED:
529 		task_attr = TCM_ORDERED_TAG;
530 		break;
531 	case FCP_PTA_ACA:
532 		task_attr = TCM_ACA_TAG;
533 		break;
534 	case FCP_PTA_SIMPLE:
535 	default:
536 		task_attr = TCM_SIMPLE_TAG;
537 	}
538 
539 	fc_seq_set_resp(cmd->seq, ft_recv_seq, cmd);
540 	cmd->se_cmd.tag = fc_seq_exch(cmd->seq)->rxid;
541 
542 	/*
543 	 * Use a single se_cmd->cmd_kref as we expect to release se_cmd
544 	 * directly from ft_check_stop_free callback in response path.
545 	 */
546 	if (target_init_cmd(&cmd->se_cmd, cmd->sess->se_sess,
547 			    &cmd->ft_sense_buffer[0],
548 			    scsilun_to_int(&fcp->fc_lun), ntohl(fcp->fc_dl),
549 			    task_attr, data_dir, TARGET_SCF_ACK_KREF))
550 		goto err;
551 
552 	if (target_submit_prep(&cmd->se_cmd, fcp->fc_cdb, NULL, 0, NULL, 0,
553 			       NULL, 0, GFP_KERNEL))
554 		return;
555 
556 	target_submit(&cmd->se_cmd);
557 	pr_debug("r_ctl %x target_submit_cmd %p\n", fh->fh_r_ctl, cmd);
558 	return;
559 
560 err:
561 	ft_send_resp_code_and_free(cmd, FCP_CMND_FIELDS_INVALID);
562 }
563