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 */
31static 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
63void 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
69static 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
85void 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
92int 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 */
100int 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 */
177int 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 */
229static 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 */
265static 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 */
308static 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 */
320static 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 */
330static 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 */
375void 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
410void ft_aborted_task(struct se_cmd *se_cmd)
411{
412	return;
413}
414
415static void ft_send_work(struct work_struct *work);
416
417/*
418 * Handle incoming FCP command.
419 */
420static 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
448busy:
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 */
460void 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 */
485static 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
560err:
561	ft_send_resp_code_and_free(cmd, FCP_CMND_FIELDS_INVALID);
562}
563