xref: /openbmc/linux/drivers/scsi/libfc/fc_exch.c (revision a0548edf)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright(c) 2007 Intel Corporation. All rights reserved.
4  * Copyright(c) 2008 Red Hat, Inc.  All rights reserved.
5  * Copyright(c) 2008 Mike Christie
6  *
7  * Maintained at www.Open-FCoE.org
8  */
9 
10 /*
11  * Fibre Channel exchange and sequence handling.
12  */
13 
14 #include <linux/timer.h>
15 #include <linux/slab.h>
16 #include <linux/err.h>
17 #include <linux/export.h>
18 #include <linux/log2.h>
19 
20 #include <scsi/fc/fc_fc2.h>
21 
22 #include <scsi/libfc.h>
23 
24 #include "fc_libfc.h"
25 
26 u16	fc_cpu_mask;		/* cpu mask for possible cpus */
27 EXPORT_SYMBOL(fc_cpu_mask);
28 static u16	fc_cpu_order;	/* 2's power to represent total possible cpus */
29 static struct kmem_cache *fc_em_cachep;	       /* cache for exchanges */
30 static struct workqueue_struct *fc_exch_workqueue;
31 
32 /*
33  * Structure and function definitions for managing Fibre Channel Exchanges
34  * and Sequences.
35  *
36  * The three primary structures used here are fc_exch_mgr, fc_exch, and fc_seq.
37  *
38  * fc_exch_mgr holds the exchange state for an N port
39  *
40  * fc_exch holds state for one exchange and links to its active sequence.
41  *
42  * fc_seq holds the state for an individual sequence.
43  */
44 
45 /**
46  * struct fc_exch_pool - Per cpu exchange pool
47  * @next_index:	  Next possible free exchange index
48  * @total_exches: Total allocated exchanges
49  * @lock:	  Exch pool lock
50  * @ex_list:	  List of exchanges
51  * @left:	  Cache of free slot in exch array
52  * @right:	  Cache of free slot in exch array
53  *
54  * This structure manages per cpu exchanges in array of exchange pointers.
55  * This array is allocated followed by struct fc_exch_pool memory for
56  * assigned range of exchanges to per cpu pool.
57  */
58 struct fc_exch_pool {
59 	spinlock_t	 lock;
60 	struct list_head ex_list;
61 	u16		 next_index;
62 	u16		 total_exches;
63 
64 	u16		 left;
65 	u16		 right;
66 } ____cacheline_aligned_in_smp;
67 
68 /**
69  * struct fc_exch_mgr - The Exchange Manager (EM).
70  * @class:	    Default class for new sequences
71  * @kref:	    Reference counter
72  * @min_xid:	    Minimum exchange ID
73  * @max_xid:	    Maximum exchange ID
74  * @ep_pool:	    Reserved exchange pointers
75  * @pool_max_index: Max exch array index in exch pool
76  * @pool:	    Per cpu exch pool
77  * @lport:	    Local exchange port
78  * @stats:	    Statistics structure
79  *
80  * This structure is the center for creating exchanges and sequences.
81  * It manages the allocation of exchange IDs.
82  */
83 struct fc_exch_mgr {
84 	struct fc_exch_pool __percpu *pool;
85 	mempool_t	*ep_pool;
86 	struct fc_lport	*lport;
87 	enum fc_class	class;
88 	struct kref	kref;
89 	u16		min_xid;
90 	u16		max_xid;
91 	u16		pool_max_index;
92 
93 	struct {
94 		atomic_t no_free_exch;
95 		atomic_t no_free_exch_xid;
96 		atomic_t xid_not_found;
97 		atomic_t xid_busy;
98 		atomic_t seq_not_found;
99 		atomic_t non_bls_resp;
100 	} stats;
101 };
102 
103 /**
104  * struct fc_exch_mgr_anchor - primary structure for list of EMs
105  * @ema_list: Exchange Manager Anchor list
106  * @mp:	      Exchange Manager associated with this anchor
107  * @match:    Routine to determine if this anchor's EM should be used
108  *
109  * When walking the list of anchors the match routine will be called
110  * for each anchor to determine if that EM should be used. The last
111  * anchor in the list will always match to handle any exchanges not
112  * handled by other EMs. The non-default EMs would be added to the
113  * anchor list by HW that provides offloads.
114  */
115 struct fc_exch_mgr_anchor {
116 	struct list_head ema_list;
117 	struct fc_exch_mgr *mp;
118 	bool (*match)(struct fc_frame *);
119 };
120 
121 static void fc_exch_rrq(struct fc_exch *);
122 static void fc_seq_ls_acc(struct fc_frame *);
123 static void fc_seq_ls_rjt(struct fc_frame *, enum fc_els_rjt_reason,
124 			  enum fc_els_rjt_explan);
125 static void fc_exch_els_rec(struct fc_frame *);
126 static void fc_exch_els_rrq(struct fc_frame *);
127 
128 /*
129  * Internal implementation notes.
130  *
131  * The exchange manager is one by default in libfc but LLD may choose
132  * to have one per CPU. The sequence manager is one per exchange manager
133  * and currently never separated.
134  *
135  * Section 9.8 in FC-FS-2 specifies:  "The SEQ_ID is a one-byte field
136  * assigned by the Sequence Initiator that shall be unique for a specific
137  * D_ID and S_ID pair while the Sequence is open."   Note that it isn't
138  * qualified by exchange ID, which one might think it would be.
139  * In practice this limits the number of open sequences and exchanges to 256
140  * per session.	 For most targets we could treat this limit as per exchange.
141  *
142  * The exchange and its sequence are freed when the last sequence is received.
143  * It's possible for the remote port to leave an exchange open without
144  * sending any sequences.
145  *
146  * Notes on reference counts:
147  *
148  * Exchanges are reference counted and exchange gets freed when the reference
149  * count becomes zero.
150  *
151  * Timeouts:
152  * Sequences are timed out for E_D_TOV and R_A_TOV.
153  *
154  * Sequence event handling:
155  *
156  * The following events may occur on initiator sequences:
157  *
158  *	Send.
159  *	    For now, the whole thing is sent.
160  *	Receive ACK
161  *	    This applies only to class F.
162  *	    The sequence is marked complete.
163  *	ULP completion.
164  *	    The upper layer calls fc_exch_done() when done
165  *	    with exchange and sequence tuple.
166  *	RX-inferred completion.
167  *	    When we receive the next sequence on the same exchange, we can
168  *	    retire the previous sequence ID.  (XXX not implemented).
169  *	Timeout.
170  *	    R_A_TOV frees the sequence ID.  If we're waiting for ACK,
171  *	    E_D_TOV causes abort and calls upper layer response handler
172  *	    with FC_EX_TIMEOUT error.
173  *	Receive RJT
174  *	    XXX defer.
175  *	Send ABTS
176  *	    On timeout.
177  *
178  * The following events may occur on recipient sequences:
179  *
180  *	Receive
181  *	    Allocate sequence for first frame received.
182  *	    Hold during receive handler.
183  *	    Release when final frame received.
184  *	    Keep status of last N of these for the ELS RES command.  XXX TBD.
185  *	Receive ABTS
186  *	    Deallocate sequence
187  *	Send RJT
188  *	    Deallocate
189  *
190  * For now, we neglect conditions where only part of a sequence was
191  * received or transmitted, or where out-of-order receipt is detected.
192  */
193 
194 /*
195  * Locking notes:
196  *
197  * The EM code run in a per-CPU worker thread.
198  *
199  * To protect against concurrency between a worker thread code and timers,
200  * sequence allocation and deallocation must be locked.
201  *  - exchange refcnt can be done atomicly without locks.
202  *  - sequence allocation must be locked by exch lock.
203  *  - If the EM pool lock and ex_lock must be taken at the same time, then the
204  *    EM pool lock must be taken before the ex_lock.
205  */
206 
207 /*
208  * opcode names for debugging.
209  */
210 static char *fc_exch_rctl_names[] = FC_RCTL_NAMES_INIT;
211 
212 /**
213  * fc_exch_name_lookup() - Lookup name by opcode
214  * @op:	       Opcode to be looked up
215  * @table:     Opcode/name table
216  * @max_index: Index not to be exceeded
217  *
218  * This routine is used to determine a human-readable string identifying
219  * a R_CTL opcode.
220  */
fc_exch_name_lookup(unsigned int op,char ** table,unsigned int max_index)221 static inline const char *fc_exch_name_lookup(unsigned int op, char **table,
222 					      unsigned int max_index)
223 {
224 	const char *name = NULL;
225 
226 	if (op < max_index)
227 		name = table[op];
228 	if (!name)
229 		name = "unknown";
230 	return name;
231 }
232 
233 /**
234  * fc_exch_rctl_name() - Wrapper routine for fc_exch_name_lookup()
235  * @op: The opcode to be looked up
236  */
fc_exch_rctl_name(unsigned int op)237 static const char *fc_exch_rctl_name(unsigned int op)
238 {
239 	return fc_exch_name_lookup(op, fc_exch_rctl_names,
240 				   ARRAY_SIZE(fc_exch_rctl_names));
241 }
242 
243 /**
244  * fc_exch_hold() - Increment an exchange's reference count
245  * @ep: Echange to be held
246  */
fc_exch_hold(struct fc_exch * ep)247 static inline void fc_exch_hold(struct fc_exch *ep)
248 {
249 	atomic_inc(&ep->ex_refcnt);
250 }
251 
252 /**
253  * fc_exch_setup_hdr() - Initialize a FC header by initializing some fields
254  *			 and determine SOF and EOF.
255  * @ep:	   The exchange to that will use the header
256  * @fp:	   The frame whose header is to be modified
257  * @f_ctl: F_CTL bits that will be used for the frame header
258  *
259  * The fields initialized by this routine are: fh_ox_id, fh_rx_id,
260  * fh_seq_id, fh_seq_cnt and the SOF and EOF.
261  */
fc_exch_setup_hdr(struct fc_exch * ep,struct fc_frame * fp,u32 f_ctl)262 static void fc_exch_setup_hdr(struct fc_exch *ep, struct fc_frame *fp,
263 			      u32 f_ctl)
264 {
265 	struct fc_frame_header *fh = fc_frame_header_get(fp);
266 	u16 fill;
267 
268 	fr_sof(fp) = ep->class;
269 	if (ep->seq.cnt)
270 		fr_sof(fp) = fc_sof_normal(ep->class);
271 
272 	if (f_ctl & FC_FC_END_SEQ) {
273 		fr_eof(fp) = FC_EOF_T;
274 		if (fc_sof_needs_ack((enum fc_sof)ep->class))
275 			fr_eof(fp) = FC_EOF_N;
276 		/*
277 		 * From F_CTL.
278 		 * The number of fill bytes to make the length a 4-byte
279 		 * multiple is the low order 2-bits of the f_ctl.
280 		 * The fill itself will have been cleared by the frame
281 		 * allocation.
282 		 * After this, the length will be even, as expected by
283 		 * the transport.
284 		 */
285 		fill = fr_len(fp) & 3;
286 		if (fill) {
287 			fill = 4 - fill;
288 			/* TODO, this may be a problem with fragmented skb */
289 			skb_put(fp_skb(fp), fill);
290 			hton24(fh->fh_f_ctl, f_ctl | fill);
291 		}
292 	} else {
293 		WARN_ON(fr_len(fp) % 4 != 0);	/* no pad to non last frame */
294 		fr_eof(fp) = FC_EOF_N;
295 	}
296 
297 	/* Initialize remaining fh fields from fc_fill_fc_hdr */
298 	fh->fh_ox_id = htons(ep->oxid);
299 	fh->fh_rx_id = htons(ep->rxid);
300 	fh->fh_seq_id = ep->seq.id;
301 	fh->fh_seq_cnt = htons(ep->seq.cnt);
302 }
303 
304 /**
305  * fc_exch_release() - Decrement an exchange's reference count
306  * @ep: Exchange to be released
307  *
308  * If the reference count reaches zero and the exchange is complete,
309  * it is freed.
310  */
fc_exch_release(struct fc_exch * ep)311 static void fc_exch_release(struct fc_exch *ep)
312 {
313 	struct fc_exch_mgr *mp;
314 
315 	if (atomic_dec_and_test(&ep->ex_refcnt)) {
316 		mp = ep->em;
317 		if (ep->destructor)
318 			ep->destructor(&ep->seq, ep->arg);
319 		WARN_ON(!(ep->esb_stat & ESB_ST_COMPLETE));
320 		mempool_free(ep, mp->ep_pool);
321 	}
322 }
323 
324 /**
325  * fc_exch_timer_cancel() - cancel exch timer
326  * @ep:		The exchange whose timer to be canceled
327  */
fc_exch_timer_cancel(struct fc_exch * ep)328 static inline void fc_exch_timer_cancel(struct fc_exch *ep)
329 {
330 	if (cancel_delayed_work(&ep->timeout_work)) {
331 		FC_EXCH_DBG(ep, "Exchange timer canceled\n");
332 		atomic_dec(&ep->ex_refcnt); /* drop hold for timer */
333 	}
334 }
335 
336 /**
337  * fc_exch_timer_set_locked() - Start a timer for an exchange w/ the
338  *				the exchange lock held
339  * @ep:		The exchange whose timer will start
340  * @timer_msec: The timeout period
341  *
342  * Used for upper level protocols to time out the exchange.
343  * The timer is cancelled when it fires or when the exchange completes.
344  */
fc_exch_timer_set_locked(struct fc_exch * ep,unsigned int timer_msec)345 static inline void fc_exch_timer_set_locked(struct fc_exch *ep,
346 					    unsigned int timer_msec)
347 {
348 	if (ep->state & (FC_EX_RST_CLEANUP | FC_EX_DONE))
349 		return;
350 
351 	FC_EXCH_DBG(ep, "Exchange timer armed : %d msecs\n", timer_msec);
352 
353 	fc_exch_hold(ep);		/* hold for timer */
354 	if (!queue_delayed_work(fc_exch_workqueue, &ep->timeout_work,
355 				msecs_to_jiffies(timer_msec))) {
356 		FC_EXCH_DBG(ep, "Exchange already queued\n");
357 		fc_exch_release(ep);
358 	}
359 }
360 
361 /**
362  * fc_exch_timer_set() - Lock the exchange and set the timer
363  * @ep:		The exchange whose timer will start
364  * @timer_msec: The timeout period
365  */
fc_exch_timer_set(struct fc_exch * ep,unsigned int timer_msec)366 static void fc_exch_timer_set(struct fc_exch *ep, unsigned int timer_msec)
367 {
368 	spin_lock_bh(&ep->ex_lock);
369 	fc_exch_timer_set_locked(ep, timer_msec);
370 	spin_unlock_bh(&ep->ex_lock);
371 }
372 
373 /**
374  * fc_exch_done_locked() - Complete an exchange with the exchange lock held
375  * @ep: The exchange that is complete
376  *
377  * Note: May sleep if invoked from outside a response handler.
378  */
fc_exch_done_locked(struct fc_exch * ep)379 static int fc_exch_done_locked(struct fc_exch *ep)
380 {
381 	int rc = 1;
382 
383 	/*
384 	 * We must check for completion in case there are two threads
385 	 * tyring to complete this. But the rrq code will reuse the
386 	 * ep, and in that case we only clear the resp and set it as
387 	 * complete, so it can be reused by the timer to send the rrq.
388 	 */
389 	if (ep->state & FC_EX_DONE)
390 		return rc;
391 	ep->esb_stat |= ESB_ST_COMPLETE;
392 
393 	if (!(ep->esb_stat & ESB_ST_REC_QUAL)) {
394 		ep->state |= FC_EX_DONE;
395 		fc_exch_timer_cancel(ep);
396 		rc = 0;
397 	}
398 	return rc;
399 }
400 
401 static struct fc_exch fc_quarantine_exch;
402 
403 /**
404  * fc_exch_ptr_get() - Return an exchange from an exchange pool
405  * @pool:  Exchange Pool to get an exchange from
406  * @index: Index of the exchange within the pool
407  *
408  * Use the index to get an exchange from within an exchange pool. exches
409  * will point to an array of exchange pointers. The index will select
410  * the exchange within the array.
411  */
fc_exch_ptr_get(struct fc_exch_pool * pool,u16 index)412 static inline struct fc_exch *fc_exch_ptr_get(struct fc_exch_pool *pool,
413 					      u16 index)
414 {
415 	struct fc_exch **exches = (struct fc_exch **)(pool + 1);
416 	return exches[index];
417 }
418 
419 /**
420  * fc_exch_ptr_set() - Assign an exchange to a slot in an exchange pool
421  * @pool:  The pool to assign the exchange to
422  * @index: The index in the pool where the exchange will be assigned
423  * @ep:	   The exchange to assign to the pool
424  */
fc_exch_ptr_set(struct fc_exch_pool * pool,u16 index,struct fc_exch * ep)425 static inline void fc_exch_ptr_set(struct fc_exch_pool *pool, u16 index,
426 				   struct fc_exch *ep)
427 {
428 	((struct fc_exch **)(pool + 1))[index] = ep;
429 }
430 
431 /**
432  * fc_exch_delete() - Delete an exchange
433  * @ep: The exchange to be deleted
434  */
fc_exch_delete(struct fc_exch * ep)435 static void fc_exch_delete(struct fc_exch *ep)
436 {
437 	struct fc_exch_pool *pool;
438 	u16 index;
439 
440 	pool = ep->pool;
441 	spin_lock_bh(&pool->lock);
442 	WARN_ON(pool->total_exches <= 0);
443 	pool->total_exches--;
444 
445 	/* update cache of free slot */
446 	index = (ep->xid - ep->em->min_xid) >> fc_cpu_order;
447 	if (!(ep->state & FC_EX_QUARANTINE)) {
448 		if (pool->left == FC_XID_UNKNOWN)
449 			pool->left = index;
450 		else if (pool->right == FC_XID_UNKNOWN)
451 			pool->right = index;
452 		else
453 			pool->next_index = index;
454 		fc_exch_ptr_set(pool, index, NULL);
455 	} else {
456 		fc_exch_ptr_set(pool, index, &fc_quarantine_exch);
457 	}
458 	list_del(&ep->ex_list);
459 	spin_unlock_bh(&pool->lock);
460 	fc_exch_release(ep);	/* drop hold for exch in mp */
461 }
462 
fc_seq_send_locked(struct fc_lport * lport,struct fc_seq * sp,struct fc_frame * fp)463 static int fc_seq_send_locked(struct fc_lport *lport, struct fc_seq *sp,
464 			      struct fc_frame *fp)
465 {
466 	struct fc_exch *ep;
467 	struct fc_frame_header *fh = fc_frame_header_get(fp);
468 	int error = -ENXIO;
469 	u32 f_ctl;
470 	u8 fh_type = fh->fh_type;
471 
472 	ep = fc_seq_exch(sp);
473 
474 	if (ep->esb_stat & (ESB_ST_COMPLETE | ESB_ST_ABNORMAL)) {
475 		fc_frame_free(fp);
476 		goto out;
477 	}
478 
479 	WARN_ON(!(ep->esb_stat & ESB_ST_SEQ_INIT));
480 
481 	f_ctl = ntoh24(fh->fh_f_ctl);
482 	fc_exch_setup_hdr(ep, fp, f_ctl);
483 	fr_encaps(fp) = ep->encaps;
484 
485 	/*
486 	 * update sequence count if this frame is carrying
487 	 * multiple FC frames when sequence offload is enabled
488 	 * by LLD.
489 	 */
490 	if (fr_max_payload(fp))
491 		sp->cnt += DIV_ROUND_UP((fr_len(fp) - sizeof(*fh)),
492 					fr_max_payload(fp));
493 	else
494 		sp->cnt++;
495 
496 	/*
497 	 * Send the frame.
498 	 */
499 	error = lport->tt.frame_send(lport, fp);
500 
501 	if (fh_type == FC_TYPE_BLS)
502 		goto out;
503 
504 	/*
505 	 * Update the exchange and sequence flags,
506 	 * assuming all frames for the sequence have been sent.
507 	 * We can only be called to send once for each sequence.
508 	 */
509 	ep->f_ctl = f_ctl & ~FC_FC_FIRST_SEQ;	/* not first seq */
510 	if (f_ctl & FC_FC_SEQ_INIT)
511 		ep->esb_stat &= ~ESB_ST_SEQ_INIT;
512 out:
513 	return error;
514 }
515 
516 /**
517  * fc_seq_send() - Send a frame using existing sequence/exchange pair
518  * @lport: The local port that the exchange will be sent on
519  * @sp:	   The sequence to be sent
520  * @fp:	   The frame to be sent on the exchange
521  *
522  * Note: The frame will be freed either by a direct call to fc_frame_free(fp)
523  * or indirectly by calling libfc_function_template.frame_send().
524  */
fc_seq_send(struct fc_lport * lport,struct fc_seq * sp,struct fc_frame * fp)525 int fc_seq_send(struct fc_lport *lport, struct fc_seq *sp, struct fc_frame *fp)
526 {
527 	struct fc_exch *ep;
528 	int error;
529 	ep = fc_seq_exch(sp);
530 	spin_lock_bh(&ep->ex_lock);
531 	error = fc_seq_send_locked(lport, sp, fp);
532 	spin_unlock_bh(&ep->ex_lock);
533 	return error;
534 }
535 EXPORT_SYMBOL(fc_seq_send);
536 
537 /**
538  * fc_seq_alloc() - Allocate a sequence for a given exchange
539  * @ep:	    The exchange to allocate a new sequence for
540  * @seq_id: The sequence ID to be used
541  *
542  * We don't support multiple originated sequences on the same exchange.
543  * By implication, any previously originated sequence on this exchange
544  * is complete, and we reallocate the same sequence.
545  */
fc_seq_alloc(struct fc_exch * ep,u8 seq_id)546 static struct fc_seq *fc_seq_alloc(struct fc_exch *ep, u8 seq_id)
547 {
548 	struct fc_seq *sp;
549 
550 	sp = &ep->seq;
551 	sp->ssb_stat = 0;
552 	sp->cnt = 0;
553 	sp->id = seq_id;
554 	return sp;
555 }
556 
557 /**
558  * fc_seq_start_next_locked() - Allocate a new sequence on the same
559  *				exchange as the supplied sequence
560  * @sp: The sequence/exchange to get a new sequence for
561  */
fc_seq_start_next_locked(struct fc_seq * sp)562 static struct fc_seq *fc_seq_start_next_locked(struct fc_seq *sp)
563 {
564 	struct fc_exch *ep = fc_seq_exch(sp);
565 
566 	sp = fc_seq_alloc(ep, ep->seq_id++);
567 	FC_EXCH_DBG(ep, "f_ctl %6x seq %2x\n",
568 		    ep->f_ctl, sp->id);
569 	return sp;
570 }
571 
572 /**
573  * fc_seq_start_next() - Lock the exchange and get a new sequence
574  *			 for a given sequence/exchange pair
575  * @sp: The sequence/exchange to get a new exchange for
576  */
fc_seq_start_next(struct fc_seq * sp)577 struct fc_seq *fc_seq_start_next(struct fc_seq *sp)
578 {
579 	struct fc_exch *ep = fc_seq_exch(sp);
580 
581 	spin_lock_bh(&ep->ex_lock);
582 	sp = fc_seq_start_next_locked(sp);
583 	spin_unlock_bh(&ep->ex_lock);
584 
585 	return sp;
586 }
587 EXPORT_SYMBOL(fc_seq_start_next);
588 
589 /*
590  * Set the response handler for the exchange associated with a sequence.
591  *
592  * Note: May sleep if invoked from outside a response handler.
593  */
fc_seq_set_resp(struct fc_seq * sp,void (* resp)(struct fc_seq *,struct fc_frame *,void *),void * arg)594 void fc_seq_set_resp(struct fc_seq *sp,
595 		     void (*resp)(struct fc_seq *, struct fc_frame *, void *),
596 		     void *arg)
597 {
598 	struct fc_exch *ep = fc_seq_exch(sp);
599 	DEFINE_WAIT(wait);
600 
601 	spin_lock_bh(&ep->ex_lock);
602 	while (ep->resp_active && ep->resp_task != current) {
603 		prepare_to_wait(&ep->resp_wq, &wait, TASK_UNINTERRUPTIBLE);
604 		spin_unlock_bh(&ep->ex_lock);
605 
606 		schedule();
607 
608 		spin_lock_bh(&ep->ex_lock);
609 	}
610 	finish_wait(&ep->resp_wq, &wait);
611 	ep->resp = resp;
612 	ep->arg = arg;
613 	spin_unlock_bh(&ep->ex_lock);
614 }
615 EXPORT_SYMBOL(fc_seq_set_resp);
616 
617 /**
618  * fc_exch_abort_locked() - Abort an exchange
619  * @ep:	The exchange to be aborted
620  * @timer_msec: The period of time to wait before aborting
621  *
622  * Abort an exchange and sequence. Generally called because of a
623  * exchange timeout or an abort from the upper layer.
624  *
625  * A timer_msec can be specified for abort timeout, if non-zero
626  * timer_msec value is specified then exchange resp handler
627  * will be called with timeout error if no response to abort.
628  *
629  * Locking notes:  Called with exch lock held
630  *
631  * Return value: 0 on success else error code
632  */
fc_exch_abort_locked(struct fc_exch * ep,unsigned int timer_msec)633 static int fc_exch_abort_locked(struct fc_exch *ep,
634 				unsigned int timer_msec)
635 {
636 	struct fc_seq *sp;
637 	struct fc_frame *fp;
638 	int error;
639 
640 	FC_EXCH_DBG(ep, "exch: abort, time %d msecs\n", timer_msec);
641 	if (ep->esb_stat & (ESB_ST_COMPLETE | ESB_ST_ABNORMAL) ||
642 	    ep->state & (FC_EX_DONE | FC_EX_RST_CLEANUP)) {
643 		FC_EXCH_DBG(ep, "exch: already completed esb %x state %x\n",
644 			    ep->esb_stat, ep->state);
645 		return -ENXIO;
646 	}
647 
648 	/*
649 	 * Send the abort on a new sequence if possible.
650 	 */
651 	sp = fc_seq_start_next_locked(&ep->seq);
652 	if (!sp)
653 		return -ENOMEM;
654 
655 	if (timer_msec)
656 		fc_exch_timer_set_locked(ep, timer_msec);
657 
658 	if (ep->sid) {
659 		/*
660 		 * Send an abort for the sequence that timed out.
661 		 */
662 		fp = fc_frame_alloc(ep->lp, 0);
663 		if (fp) {
664 			ep->esb_stat |= ESB_ST_SEQ_INIT;
665 			fc_fill_fc_hdr(fp, FC_RCTL_BA_ABTS, ep->did, ep->sid,
666 				       FC_TYPE_BLS, FC_FC_END_SEQ |
667 				       FC_FC_SEQ_INIT, 0);
668 			error = fc_seq_send_locked(ep->lp, sp, fp);
669 		} else {
670 			error = -ENOBUFS;
671 		}
672 	} else {
673 		/*
674 		 * If not logged into the fabric, don't send ABTS but leave
675 		 * sequence active until next timeout.
676 		 */
677 		error = 0;
678 	}
679 	ep->esb_stat |= ESB_ST_ABNORMAL;
680 	return error;
681 }
682 
683 /**
684  * fc_seq_exch_abort() - Abort an exchange and sequence
685  * @req_sp:	The sequence to be aborted
686  * @timer_msec: The period of time to wait before aborting
687  *
688  * Generally called because of a timeout or an abort from the upper layer.
689  *
690  * Return value: 0 on success else error code
691  */
fc_seq_exch_abort(const struct fc_seq * req_sp,unsigned int timer_msec)692 int fc_seq_exch_abort(const struct fc_seq *req_sp, unsigned int timer_msec)
693 {
694 	struct fc_exch *ep;
695 	int error;
696 
697 	ep = fc_seq_exch(req_sp);
698 	spin_lock_bh(&ep->ex_lock);
699 	error = fc_exch_abort_locked(ep, timer_msec);
700 	spin_unlock_bh(&ep->ex_lock);
701 	return error;
702 }
703 
704 /**
705  * fc_invoke_resp() - invoke ep->resp()
706  * @ep:	   The exchange to be operated on
707  * @fp:	   The frame pointer to pass through to ->resp()
708  * @sp:	   The sequence pointer to pass through to ->resp()
709  *
710  * Notes:
711  * It is assumed that after initialization finished (this means the
712  * first unlock of ex_lock after fc_exch_alloc()) ep->resp and ep->arg are
713  * modified only via fc_seq_set_resp(). This guarantees that none of these
714  * two variables changes if ep->resp_active > 0.
715  *
716  * If an fc_seq_set_resp() call is busy modifying ep->resp and ep->arg when
717  * this function is invoked, the first spin_lock_bh() call in this function
718  * will wait until fc_seq_set_resp() has finished modifying these variables.
719  *
720  * Since fc_exch_done() invokes fc_seq_set_resp() it is guaranteed that that
721  * ep->resp() won't be invoked after fc_exch_done() has returned.
722  *
723  * The response handler itself may invoke fc_exch_done(), which will clear the
724  * ep->resp pointer.
725  *
726  * Return value:
727  * Returns true if and only if ep->resp has been invoked.
728  */
fc_invoke_resp(struct fc_exch * ep,struct fc_seq * sp,struct fc_frame * fp)729 static bool fc_invoke_resp(struct fc_exch *ep, struct fc_seq *sp,
730 			   struct fc_frame *fp)
731 {
732 	void (*resp)(struct fc_seq *, struct fc_frame *fp, void *arg);
733 	void *arg;
734 	bool res = false;
735 
736 	spin_lock_bh(&ep->ex_lock);
737 	ep->resp_active++;
738 	if (ep->resp_task != current)
739 		ep->resp_task = !ep->resp_task ? current : NULL;
740 	resp = ep->resp;
741 	arg = ep->arg;
742 	spin_unlock_bh(&ep->ex_lock);
743 
744 	if (resp) {
745 		resp(sp, fp, arg);
746 		res = true;
747 	}
748 
749 	spin_lock_bh(&ep->ex_lock);
750 	if (--ep->resp_active == 0)
751 		ep->resp_task = NULL;
752 	spin_unlock_bh(&ep->ex_lock);
753 
754 	if (ep->resp_active == 0)
755 		wake_up(&ep->resp_wq);
756 
757 	return res;
758 }
759 
760 /**
761  * fc_exch_timeout() - Handle exchange timer expiration
762  * @work: The work_struct identifying the exchange that timed out
763  */
fc_exch_timeout(struct work_struct * work)764 static void fc_exch_timeout(struct work_struct *work)
765 {
766 	struct fc_exch *ep = container_of(work, struct fc_exch,
767 					  timeout_work.work);
768 	struct fc_seq *sp = &ep->seq;
769 	u32 e_stat;
770 	int rc = 1;
771 
772 	FC_EXCH_DBG(ep, "Exchange timed out state %x\n", ep->state);
773 
774 	spin_lock_bh(&ep->ex_lock);
775 	if (ep->state & (FC_EX_RST_CLEANUP | FC_EX_DONE))
776 		goto unlock;
777 
778 	e_stat = ep->esb_stat;
779 	if (e_stat & ESB_ST_COMPLETE) {
780 		ep->esb_stat = e_stat & ~ESB_ST_REC_QUAL;
781 		spin_unlock_bh(&ep->ex_lock);
782 		if (e_stat & ESB_ST_REC_QUAL)
783 			fc_exch_rrq(ep);
784 		goto done;
785 	} else {
786 		if (e_stat & ESB_ST_ABNORMAL)
787 			rc = fc_exch_done_locked(ep);
788 		spin_unlock_bh(&ep->ex_lock);
789 		if (!rc)
790 			fc_exch_delete(ep);
791 		fc_invoke_resp(ep, sp, ERR_PTR(-FC_EX_TIMEOUT));
792 		fc_seq_set_resp(sp, NULL, ep->arg);
793 		fc_seq_exch_abort(sp, 2 * ep->r_a_tov);
794 		goto done;
795 	}
796 unlock:
797 	spin_unlock_bh(&ep->ex_lock);
798 done:
799 	/*
800 	 * This release matches the hold taken when the timer was set.
801 	 */
802 	fc_exch_release(ep);
803 }
804 
805 /**
806  * fc_exch_em_alloc() - Allocate an exchange from a specified EM.
807  * @lport: The local port that the exchange is for
808  * @mp:	   The exchange manager that will allocate the exchange
809  *
810  * Returns pointer to allocated fc_exch with exch lock held.
811  */
fc_exch_em_alloc(struct fc_lport * lport,struct fc_exch_mgr * mp)812 static struct fc_exch *fc_exch_em_alloc(struct fc_lport *lport,
813 					struct fc_exch_mgr *mp)
814 {
815 	struct fc_exch *ep;
816 	unsigned int cpu;
817 	u16 index;
818 	struct fc_exch_pool *pool;
819 
820 	/* allocate memory for exchange */
821 	ep = mempool_alloc(mp->ep_pool, GFP_ATOMIC);
822 	if (!ep) {
823 		atomic_inc(&mp->stats.no_free_exch);
824 		goto out;
825 	}
826 	memset(ep, 0, sizeof(*ep));
827 
828 	cpu = raw_smp_processor_id();
829 	pool = per_cpu_ptr(mp->pool, cpu);
830 	spin_lock_bh(&pool->lock);
831 
832 	/* peek cache of free slot */
833 	if (pool->left != FC_XID_UNKNOWN) {
834 		if (!WARN_ON(fc_exch_ptr_get(pool, pool->left))) {
835 			index = pool->left;
836 			pool->left = FC_XID_UNKNOWN;
837 			goto hit;
838 		}
839 	}
840 	if (pool->right != FC_XID_UNKNOWN) {
841 		if (!WARN_ON(fc_exch_ptr_get(pool, pool->right))) {
842 			index = pool->right;
843 			pool->right = FC_XID_UNKNOWN;
844 			goto hit;
845 		}
846 	}
847 
848 	index = pool->next_index;
849 	/* allocate new exch from pool */
850 	while (fc_exch_ptr_get(pool, index)) {
851 		index = index == mp->pool_max_index ? 0 : index + 1;
852 		if (index == pool->next_index)
853 			goto err;
854 	}
855 	pool->next_index = index == mp->pool_max_index ? 0 : index + 1;
856 hit:
857 	fc_exch_hold(ep);	/* hold for exch in mp */
858 	spin_lock_init(&ep->ex_lock);
859 	/*
860 	 * Hold exch lock for caller to prevent fc_exch_reset()
861 	 * from releasing exch	while fc_exch_alloc() caller is
862 	 * still working on exch.
863 	 */
864 	spin_lock_bh(&ep->ex_lock);
865 
866 	fc_exch_ptr_set(pool, index, ep);
867 	list_add_tail(&ep->ex_list, &pool->ex_list);
868 	fc_seq_alloc(ep, ep->seq_id++);
869 	pool->total_exches++;
870 	spin_unlock_bh(&pool->lock);
871 
872 	/*
873 	 *  update exchange
874 	 */
875 	ep->oxid = ep->xid = (index << fc_cpu_order | cpu) + mp->min_xid;
876 	ep->em = mp;
877 	ep->pool = pool;
878 	ep->lp = lport;
879 	ep->f_ctl = FC_FC_FIRST_SEQ;	/* next seq is first seq */
880 	ep->rxid = FC_XID_UNKNOWN;
881 	ep->class = mp->class;
882 	ep->resp_active = 0;
883 	init_waitqueue_head(&ep->resp_wq);
884 	INIT_DELAYED_WORK(&ep->timeout_work, fc_exch_timeout);
885 out:
886 	return ep;
887 err:
888 	spin_unlock_bh(&pool->lock);
889 	atomic_inc(&mp->stats.no_free_exch_xid);
890 	mempool_free(ep, mp->ep_pool);
891 	return NULL;
892 }
893 
894 /**
895  * fc_exch_alloc() - Allocate an exchange from an EM on a
896  *		     local port's list of EMs.
897  * @lport: The local port that will own the exchange
898  * @fp:	   The FC frame that the exchange will be for
899  *
900  * This function walks the list of exchange manager(EM)
901  * anchors to select an EM for a new exchange allocation. The
902  * EM is selected when a NULL match function pointer is encountered
903  * or when a call to a match function returns true.
904  */
fc_exch_alloc(struct fc_lport * lport,struct fc_frame * fp)905 static struct fc_exch *fc_exch_alloc(struct fc_lport *lport,
906 				     struct fc_frame *fp)
907 {
908 	struct fc_exch_mgr_anchor *ema;
909 	struct fc_exch *ep;
910 
911 	list_for_each_entry(ema, &lport->ema_list, ema_list) {
912 		if (!ema->match || ema->match(fp)) {
913 			ep = fc_exch_em_alloc(lport, ema->mp);
914 			if (ep)
915 				return ep;
916 		}
917 	}
918 	return NULL;
919 }
920 
921 /**
922  * fc_exch_find() - Lookup and hold an exchange
923  * @mp:	 The exchange manager to lookup the exchange from
924  * @xid: The XID of the exchange to look up
925  */
fc_exch_find(struct fc_exch_mgr * mp,u16 xid)926 static struct fc_exch *fc_exch_find(struct fc_exch_mgr *mp, u16 xid)
927 {
928 	struct fc_lport *lport = mp->lport;
929 	struct fc_exch_pool *pool;
930 	struct fc_exch *ep = NULL;
931 	u16 cpu = xid & fc_cpu_mask;
932 
933 	if (xid == FC_XID_UNKNOWN)
934 		return NULL;
935 
936 	if (cpu >= nr_cpu_ids || !cpu_possible(cpu)) {
937 		pr_err("host%u: lport %6.6x: xid %d invalid CPU %d\n:",
938 		       lport->host->host_no, lport->port_id, xid, cpu);
939 		return NULL;
940 	}
941 
942 	if ((xid >= mp->min_xid) && (xid <= mp->max_xid)) {
943 		pool = per_cpu_ptr(mp->pool, cpu);
944 		spin_lock_bh(&pool->lock);
945 		ep = fc_exch_ptr_get(pool, (xid - mp->min_xid) >> fc_cpu_order);
946 		if (ep == &fc_quarantine_exch) {
947 			FC_LPORT_DBG(lport, "xid %x quarantined\n", xid);
948 			ep = NULL;
949 		}
950 		if (ep) {
951 			WARN_ON(ep->xid != xid);
952 			fc_exch_hold(ep);
953 		}
954 		spin_unlock_bh(&pool->lock);
955 	}
956 	return ep;
957 }
958 
959 
960 /**
961  * fc_exch_done() - Indicate that an exchange/sequence tuple is complete and
962  *		    the memory allocated for the related objects may be freed.
963  * @sp: The sequence that has completed
964  *
965  * Note: May sleep if invoked from outside a response handler.
966  */
fc_exch_done(struct fc_seq * sp)967 void fc_exch_done(struct fc_seq *sp)
968 {
969 	struct fc_exch *ep = fc_seq_exch(sp);
970 	int rc;
971 
972 	spin_lock_bh(&ep->ex_lock);
973 	rc = fc_exch_done_locked(ep);
974 	spin_unlock_bh(&ep->ex_lock);
975 
976 	fc_seq_set_resp(sp, NULL, ep->arg);
977 	if (!rc)
978 		fc_exch_delete(ep);
979 }
980 EXPORT_SYMBOL(fc_exch_done);
981 
982 /**
983  * fc_exch_resp() - Allocate a new exchange for a response frame
984  * @lport: The local port that the exchange was for
985  * @mp:	   The exchange manager to allocate the exchange from
986  * @fp:	   The response frame
987  *
988  * Sets the responder ID in the frame header.
989  */
fc_exch_resp(struct fc_lport * lport,struct fc_exch_mgr * mp,struct fc_frame * fp)990 static struct fc_exch *fc_exch_resp(struct fc_lport *lport,
991 				    struct fc_exch_mgr *mp,
992 				    struct fc_frame *fp)
993 {
994 	struct fc_exch *ep;
995 	struct fc_frame_header *fh;
996 
997 	ep = fc_exch_alloc(lport, fp);
998 	if (ep) {
999 		ep->class = fc_frame_class(fp);
1000 
1001 		/*
1002 		 * Set EX_CTX indicating we're responding on this exchange.
1003 		 */
1004 		ep->f_ctl |= FC_FC_EX_CTX;	/* we're responding */
1005 		ep->f_ctl &= ~FC_FC_FIRST_SEQ;	/* not new */
1006 		fh = fc_frame_header_get(fp);
1007 		ep->sid = ntoh24(fh->fh_d_id);
1008 		ep->did = ntoh24(fh->fh_s_id);
1009 		ep->oid = ep->did;
1010 
1011 		/*
1012 		 * Allocated exchange has placed the XID in the
1013 		 * originator field. Move it to the responder field,
1014 		 * and set the originator XID from the frame.
1015 		 */
1016 		ep->rxid = ep->xid;
1017 		ep->oxid = ntohs(fh->fh_ox_id);
1018 		ep->esb_stat |= ESB_ST_RESP | ESB_ST_SEQ_INIT;
1019 		if ((ntoh24(fh->fh_f_ctl) & FC_FC_SEQ_INIT) == 0)
1020 			ep->esb_stat &= ~ESB_ST_SEQ_INIT;
1021 
1022 		fc_exch_hold(ep);	/* hold for caller */
1023 		spin_unlock_bh(&ep->ex_lock);	/* lock from fc_exch_alloc */
1024 	}
1025 	return ep;
1026 }
1027 
1028 /**
1029  * fc_seq_lookup_recip() - Find a sequence where the other end
1030  *			   originated the sequence
1031  * @lport: The local port that the frame was sent to
1032  * @mp:	   The Exchange Manager to lookup the exchange from
1033  * @fp:	   The frame associated with the sequence we're looking for
1034  *
1035  * If fc_pf_rjt_reason is FC_RJT_NONE then this function will have a hold
1036  * on the ep that should be released by the caller.
1037  */
fc_seq_lookup_recip(struct fc_lport * lport,struct fc_exch_mgr * mp,struct fc_frame * fp)1038 static enum fc_pf_rjt_reason fc_seq_lookup_recip(struct fc_lport *lport,
1039 						 struct fc_exch_mgr *mp,
1040 						 struct fc_frame *fp)
1041 {
1042 	struct fc_frame_header *fh = fc_frame_header_get(fp);
1043 	struct fc_exch *ep = NULL;
1044 	struct fc_seq *sp = NULL;
1045 	enum fc_pf_rjt_reason reject = FC_RJT_NONE;
1046 	u32 f_ctl;
1047 	u16 xid;
1048 
1049 	f_ctl = ntoh24(fh->fh_f_ctl);
1050 	WARN_ON((f_ctl & FC_FC_SEQ_CTX) != 0);
1051 
1052 	/*
1053 	 * Lookup or create the exchange if we will be creating the sequence.
1054 	 */
1055 	if (f_ctl & FC_FC_EX_CTX) {
1056 		xid = ntohs(fh->fh_ox_id);	/* we originated exch */
1057 		ep = fc_exch_find(mp, xid);
1058 		if (!ep) {
1059 			atomic_inc(&mp->stats.xid_not_found);
1060 			reject = FC_RJT_OX_ID;
1061 			goto out;
1062 		}
1063 		if (ep->rxid == FC_XID_UNKNOWN)
1064 			ep->rxid = ntohs(fh->fh_rx_id);
1065 		else if (ep->rxid != ntohs(fh->fh_rx_id)) {
1066 			reject = FC_RJT_OX_ID;
1067 			goto rel;
1068 		}
1069 	} else {
1070 		xid = ntohs(fh->fh_rx_id);	/* we are the responder */
1071 
1072 		/*
1073 		 * Special case for MDS issuing an ELS TEST with a
1074 		 * bad rxid of 0.
1075 		 * XXX take this out once we do the proper reject.
1076 		 */
1077 		if (xid == 0 && fh->fh_r_ctl == FC_RCTL_ELS_REQ &&
1078 		    fc_frame_payload_op(fp) == ELS_TEST) {
1079 			fh->fh_rx_id = htons(FC_XID_UNKNOWN);
1080 			xid = FC_XID_UNKNOWN;
1081 		}
1082 
1083 		/*
1084 		 * new sequence - find the exchange
1085 		 */
1086 		ep = fc_exch_find(mp, xid);
1087 		if ((f_ctl & FC_FC_FIRST_SEQ) && fc_sof_is_init(fr_sof(fp))) {
1088 			if (ep) {
1089 				atomic_inc(&mp->stats.xid_busy);
1090 				reject = FC_RJT_RX_ID;
1091 				goto rel;
1092 			}
1093 			ep = fc_exch_resp(lport, mp, fp);
1094 			if (!ep) {
1095 				reject = FC_RJT_EXCH_EST;	/* XXX */
1096 				goto out;
1097 			}
1098 			xid = ep->xid;	/* get our XID */
1099 		} else if (!ep) {
1100 			atomic_inc(&mp->stats.xid_not_found);
1101 			reject = FC_RJT_RX_ID;	/* XID not found */
1102 			goto out;
1103 		}
1104 	}
1105 
1106 	spin_lock_bh(&ep->ex_lock);
1107 	/*
1108 	 * At this point, we have the exchange held.
1109 	 * Find or create the sequence.
1110 	 */
1111 	if (fc_sof_is_init(fr_sof(fp))) {
1112 		sp = &ep->seq;
1113 		sp->ssb_stat |= SSB_ST_RESP;
1114 		sp->id = fh->fh_seq_id;
1115 	} else {
1116 		sp = &ep->seq;
1117 		if (sp->id != fh->fh_seq_id) {
1118 			atomic_inc(&mp->stats.seq_not_found);
1119 			if (f_ctl & FC_FC_END_SEQ) {
1120 				/*
1121 				 * Update sequence_id based on incoming last
1122 				 * frame of sequence exchange. This is needed
1123 				 * for FC target where DDP has been used
1124 				 * on target where, stack is indicated only
1125 				 * about last frame's (payload _header) header.
1126 				 * Whereas "seq_id" which is part of
1127 				 * frame_header is allocated by initiator
1128 				 * which is totally different from "seq_id"
1129 				 * allocated when XFER_RDY was sent by target.
1130 				 * To avoid false -ve which results into not
1131 				 * sending RSP, hence write request on other
1132 				 * end never finishes.
1133 				 */
1134 				sp->ssb_stat |= SSB_ST_RESP;
1135 				sp->id = fh->fh_seq_id;
1136 			} else {
1137 				spin_unlock_bh(&ep->ex_lock);
1138 
1139 				/* sequence/exch should exist */
1140 				reject = FC_RJT_SEQ_ID;
1141 				goto rel;
1142 			}
1143 		}
1144 	}
1145 	WARN_ON(ep != fc_seq_exch(sp));
1146 
1147 	if (f_ctl & FC_FC_SEQ_INIT)
1148 		ep->esb_stat |= ESB_ST_SEQ_INIT;
1149 	spin_unlock_bh(&ep->ex_lock);
1150 
1151 	fr_seq(fp) = sp;
1152 out:
1153 	return reject;
1154 rel:
1155 	fc_exch_done(&ep->seq);
1156 	fc_exch_release(ep);	/* hold from fc_exch_find/fc_exch_resp */
1157 	return reject;
1158 }
1159 
1160 /**
1161  * fc_seq_lookup_orig() - Find a sequence where this end
1162  *			  originated the sequence
1163  * @mp:	   The Exchange Manager to lookup the exchange from
1164  * @fp:	   The frame associated with the sequence we're looking for
1165  *
1166  * Does not hold the sequence for the caller.
1167  */
fc_seq_lookup_orig(struct fc_exch_mgr * mp,struct fc_frame * fp)1168 static struct fc_seq *fc_seq_lookup_orig(struct fc_exch_mgr *mp,
1169 					 struct fc_frame *fp)
1170 {
1171 	struct fc_frame_header *fh = fc_frame_header_get(fp);
1172 	struct fc_exch *ep;
1173 	struct fc_seq *sp = NULL;
1174 	u32 f_ctl;
1175 	u16 xid;
1176 
1177 	f_ctl = ntoh24(fh->fh_f_ctl);
1178 	WARN_ON((f_ctl & FC_FC_SEQ_CTX) != FC_FC_SEQ_CTX);
1179 	xid = ntohs((f_ctl & FC_FC_EX_CTX) ? fh->fh_ox_id : fh->fh_rx_id);
1180 	ep = fc_exch_find(mp, xid);
1181 	if (!ep)
1182 		return NULL;
1183 	if (ep->seq.id == fh->fh_seq_id) {
1184 		/*
1185 		 * Save the RX_ID if we didn't previously know it.
1186 		 */
1187 		sp = &ep->seq;
1188 		if ((f_ctl & FC_FC_EX_CTX) != 0 &&
1189 		    ep->rxid == FC_XID_UNKNOWN) {
1190 			ep->rxid = ntohs(fh->fh_rx_id);
1191 		}
1192 	}
1193 	fc_exch_release(ep);
1194 	return sp;
1195 }
1196 
1197 /**
1198  * fc_exch_set_addr() - Set the source and destination IDs for an exchange
1199  * @ep:	     The exchange to set the addresses for
1200  * @orig_id: The originator's ID
1201  * @resp_id: The responder's ID
1202  *
1203  * Note this must be done before the first sequence of the exchange is sent.
1204  */
fc_exch_set_addr(struct fc_exch * ep,u32 orig_id,u32 resp_id)1205 static void fc_exch_set_addr(struct fc_exch *ep,
1206 			     u32 orig_id, u32 resp_id)
1207 {
1208 	ep->oid = orig_id;
1209 	if (ep->esb_stat & ESB_ST_RESP) {
1210 		ep->sid = resp_id;
1211 		ep->did = orig_id;
1212 	} else {
1213 		ep->sid = orig_id;
1214 		ep->did = resp_id;
1215 	}
1216 }
1217 
1218 /**
1219  * fc_seq_els_rsp_send() - Send an ELS response using information from
1220  *			   the existing sequence/exchange.
1221  * @fp:	      The received frame
1222  * @els_cmd:  The ELS command to be sent
1223  * @els_data: The ELS data to be sent
1224  *
1225  * The received frame is not freed.
1226  */
fc_seq_els_rsp_send(struct fc_frame * fp,enum fc_els_cmd els_cmd,struct fc_seq_els_data * els_data)1227 void fc_seq_els_rsp_send(struct fc_frame *fp, enum fc_els_cmd els_cmd,
1228 			 struct fc_seq_els_data *els_data)
1229 {
1230 	switch (els_cmd) {
1231 	case ELS_LS_RJT:
1232 		fc_seq_ls_rjt(fp, els_data->reason, els_data->explan);
1233 		break;
1234 	case ELS_LS_ACC:
1235 		fc_seq_ls_acc(fp);
1236 		break;
1237 	case ELS_RRQ:
1238 		fc_exch_els_rrq(fp);
1239 		break;
1240 	case ELS_REC:
1241 		fc_exch_els_rec(fp);
1242 		break;
1243 	default:
1244 		FC_LPORT_DBG(fr_dev(fp), "Invalid ELS CMD:%x\n", els_cmd);
1245 	}
1246 }
1247 EXPORT_SYMBOL_GPL(fc_seq_els_rsp_send);
1248 
1249 /**
1250  * fc_seq_send_last() - Send a sequence that is the last in the exchange
1251  * @sp:	     The sequence that is to be sent
1252  * @fp:	     The frame that will be sent on the sequence
1253  * @rctl:    The R_CTL information to be sent
1254  * @fh_type: The frame header type
1255  */
fc_seq_send_last(struct fc_seq * sp,struct fc_frame * fp,enum fc_rctl rctl,enum fc_fh_type fh_type)1256 static void fc_seq_send_last(struct fc_seq *sp, struct fc_frame *fp,
1257 			     enum fc_rctl rctl, enum fc_fh_type fh_type)
1258 {
1259 	u32 f_ctl;
1260 	struct fc_exch *ep = fc_seq_exch(sp);
1261 
1262 	f_ctl = FC_FC_LAST_SEQ | FC_FC_END_SEQ | FC_FC_SEQ_INIT;
1263 	f_ctl |= ep->f_ctl;
1264 	fc_fill_fc_hdr(fp, rctl, ep->did, ep->sid, fh_type, f_ctl, 0);
1265 	fc_seq_send_locked(ep->lp, sp, fp);
1266 }
1267 
1268 /**
1269  * fc_seq_send_ack() - Send an acknowledgement that we've received a frame
1270  * @sp:	   The sequence to send the ACK on
1271  * @rx_fp: The received frame that is being acknoledged
1272  *
1273  * Send ACK_1 (or equiv.) indicating we received something.
1274  */
fc_seq_send_ack(struct fc_seq * sp,const struct fc_frame * rx_fp)1275 static void fc_seq_send_ack(struct fc_seq *sp, const struct fc_frame *rx_fp)
1276 {
1277 	struct fc_frame *fp;
1278 	struct fc_frame_header *rx_fh;
1279 	struct fc_frame_header *fh;
1280 	struct fc_exch *ep = fc_seq_exch(sp);
1281 	struct fc_lport *lport = ep->lp;
1282 	unsigned int f_ctl;
1283 
1284 	/*
1285 	 * Don't send ACKs for class 3.
1286 	 */
1287 	if (fc_sof_needs_ack(fr_sof(rx_fp))) {
1288 		fp = fc_frame_alloc(lport, 0);
1289 		if (!fp) {
1290 			FC_EXCH_DBG(ep, "Drop ACK request, out of memory\n");
1291 			return;
1292 		}
1293 
1294 		fh = fc_frame_header_get(fp);
1295 		fh->fh_r_ctl = FC_RCTL_ACK_1;
1296 		fh->fh_type = FC_TYPE_BLS;
1297 
1298 		/*
1299 		 * Form f_ctl by inverting EX_CTX and SEQ_CTX (bits 23, 22).
1300 		 * Echo FIRST_SEQ, LAST_SEQ, END_SEQ, END_CONN, SEQ_INIT.
1301 		 * Bits 9-8 are meaningful (retransmitted or unidirectional).
1302 		 * Last ACK uses bits 7-6 (continue sequence),
1303 		 * bits 5-4 are meaningful (what kind of ACK to use).
1304 		 */
1305 		rx_fh = fc_frame_header_get(rx_fp);
1306 		f_ctl = ntoh24(rx_fh->fh_f_ctl);
1307 		f_ctl &= FC_FC_EX_CTX | FC_FC_SEQ_CTX |
1308 			FC_FC_FIRST_SEQ | FC_FC_LAST_SEQ |
1309 			FC_FC_END_SEQ | FC_FC_END_CONN | FC_FC_SEQ_INIT |
1310 			FC_FC_RETX_SEQ | FC_FC_UNI_TX;
1311 		f_ctl ^= FC_FC_EX_CTX | FC_FC_SEQ_CTX;
1312 		hton24(fh->fh_f_ctl, f_ctl);
1313 
1314 		fc_exch_setup_hdr(ep, fp, f_ctl);
1315 		fh->fh_seq_id = rx_fh->fh_seq_id;
1316 		fh->fh_seq_cnt = rx_fh->fh_seq_cnt;
1317 		fh->fh_parm_offset = htonl(1);	/* ack single frame */
1318 
1319 		fr_sof(fp) = fr_sof(rx_fp);
1320 		if (f_ctl & FC_FC_END_SEQ)
1321 			fr_eof(fp) = FC_EOF_T;
1322 		else
1323 			fr_eof(fp) = FC_EOF_N;
1324 
1325 		lport->tt.frame_send(lport, fp);
1326 	}
1327 }
1328 
1329 /**
1330  * fc_exch_send_ba_rjt() - Send BLS Reject
1331  * @rx_fp:  The frame being rejected
1332  * @reason: The reason the frame is being rejected
1333  * @explan: The explanation for the rejection
1334  *
1335  * This is for rejecting BA_ABTS only.
1336  */
fc_exch_send_ba_rjt(struct fc_frame * rx_fp,enum fc_ba_rjt_reason reason,enum fc_ba_rjt_explan explan)1337 static void fc_exch_send_ba_rjt(struct fc_frame *rx_fp,
1338 				enum fc_ba_rjt_reason reason,
1339 				enum fc_ba_rjt_explan explan)
1340 {
1341 	struct fc_frame *fp;
1342 	struct fc_frame_header *rx_fh;
1343 	struct fc_frame_header *fh;
1344 	struct fc_ba_rjt *rp;
1345 	struct fc_seq *sp;
1346 	struct fc_lport *lport;
1347 	unsigned int f_ctl;
1348 
1349 	lport = fr_dev(rx_fp);
1350 	sp = fr_seq(rx_fp);
1351 	fp = fc_frame_alloc(lport, sizeof(*rp));
1352 	if (!fp) {
1353 		FC_EXCH_DBG(fc_seq_exch(sp),
1354 			     "Drop BA_RJT request, out of memory\n");
1355 		return;
1356 	}
1357 	fh = fc_frame_header_get(fp);
1358 	rx_fh = fc_frame_header_get(rx_fp);
1359 
1360 	memset(fh, 0, sizeof(*fh) + sizeof(*rp));
1361 
1362 	rp = fc_frame_payload_get(fp, sizeof(*rp));
1363 	rp->br_reason = reason;
1364 	rp->br_explan = explan;
1365 
1366 	/*
1367 	 * seq_id, cs_ctl, df_ctl and param/offset are zero.
1368 	 */
1369 	memcpy(fh->fh_s_id, rx_fh->fh_d_id, 3);
1370 	memcpy(fh->fh_d_id, rx_fh->fh_s_id, 3);
1371 	fh->fh_ox_id = rx_fh->fh_ox_id;
1372 	fh->fh_rx_id = rx_fh->fh_rx_id;
1373 	fh->fh_seq_cnt = rx_fh->fh_seq_cnt;
1374 	fh->fh_r_ctl = FC_RCTL_BA_RJT;
1375 	fh->fh_type = FC_TYPE_BLS;
1376 
1377 	/*
1378 	 * Form f_ctl by inverting EX_CTX and SEQ_CTX (bits 23, 22).
1379 	 * Echo FIRST_SEQ, LAST_SEQ, END_SEQ, END_CONN, SEQ_INIT.
1380 	 * Bits 9-8 are meaningful (retransmitted or unidirectional).
1381 	 * Last ACK uses bits 7-6 (continue sequence),
1382 	 * bits 5-4 are meaningful (what kind of ACK to use).
1383 	 * Always set LAST_SEQ, END_SEQ.
1384 	 */
1385 	f_ctl = ntoh24(rx_fh->fh_f_ctl);
1386 	f_ctl &= FC_FC_EX_CTX | FC_FC_SEQ_CTX |
1387 		FC_FC_END_CONN | FC_FC_SEQ_INIT |
1388 		FC_FC_RETX_SEQ | FC_FC_UNI_TX;
1389 	f_ctl ^= FC_FC_EX_CTX | FC_FC_SEQ_CTX;
1390 	f_ctl |= FC_FC_LAST_SEQ | FC_FC_END_SEQ;
1391 	f_ctl &= ~FC_FC_FIRST_SEQ;
1392 	hton24(fh->fh_f_ctl, f_ctl);
1393 
1394 	fr_sof(fp) = fc_sof_class(fr_sof(rx_fp));
1395 	fr_eof(fp) = FC_EOF_T;
1396 	if (fc_sof_needs_ack(fr_sof(fp)))
1397 		fr_eof(fp) = FC_EOF_N;
1398 
1399 	lport->tt.frame_send(lport, fp);
1400 }
1401 
1402 /**
1403  * fc_exch_recv_abts() - Handle an incoming ABTS
1404  * @ep:	   The exchange the abort was on
1405  * @rx_fp: The ABTS frame
1406  *
1407  * This would be for target mode usually, but could be due to lost
1408  * FCP transfer ready, confirm or RRQ. We always handle this as an
1409  * exchange abort, ignoring the parameter.
1410  */
fc_exch_recv_abts(struct fc_exch * ep,struct fc_frame * rx_fp)1411 static void fc_exch_recv_abts(struct fc_exch *ep, struct fc_frame *rx_fp)
1412 {
1413 	struct fc_frame *fp;
1414 	struct fc_ba_acc *ap;
1415 	struct fc_frame_header *fh;
1416 	struct fc_seq *sp;
1417 
1418 	if (!ep)
1419 		goto reject;
1420 
1421 	FC_EXCH_DBG(ep, "exch: ABTS received\n");
1422 	fp = fc_frame_alloc(ep->lp, sizeof(*ap));
1423 	if (!fp) {
1424 		FC_EXCH_DBG(ep, "Drop ABTS request, out of memory\n");
1425 		goto free;
1426 	}
1427 
1428 	spin_lock_bh(&ep->ex_lock);
1429 	if (ep->esb_stat & ESB_ST_COMPLETE) {
1430 		spin_unlock_bh(&ep->ex_lock);
1431 		FC_EXCH_DBG(ep, "exch: ABTS rejected, exchange complete\n");
1432 		fc_frame_free(fp);
1433 		goto reject;
1434 	}
1435 	if (!(ep->esb_stat & ESB_ST_REC_QUAL)) {
1436 		ep->esb_stat |= ESB_ST_REC_QUAL;
1437 		fc_exch_hold(ep);		/* hold for REC_QUAL */
1438 	}
1439 	fc_exch_timer_set_locked(ep, ep->r_a_tov);
1440 	fh = fc_frame_header_get(fp);
1441 	ap = fc_frame_payload_get(fp, sizeof(*ap));
1442 	memset(ap, 0, sizeof(*ap));
1443 	sp = &ep->seq;
1444 	ap->ba_high_seq_cnt = htons(0xffff);
1445 	if (sp->ssb_stat & SSB_ST_RESP) {
1446 		ap->ba_seq_id = sp->id;
1447 		ap->ba_seq_id_val = FC_BA_SEQ_ID_VAL;
1448 		ap->ba_high_seq_cnt = fh->fh_seq_cnt;
1449 		ap->ba_low_seq_cnt = htons(sp->cnt);
1450 	}
1451 	sp = fc_seq_start_next_locked(sp);
1452 	fc_seq_send_last(sp, fp, FC_RCTL_BA_ACC, FC_TYPE_BLS);
1453 	ep->esb_stat |= ESB_ST_ABNORMAL;
1454 	spin_unlock_bh(&ep->ex_lock);
1455 
1456 free:
1457 	fc_frame_free(rx_fp);
1458 	return;
1459 
1460 reject:
1461 	fc_exch_send_ba_rjt(rx_fp, FC_BA_RJT_UNABLE, FC_BA_RJT_INV_XID);
1462 	goto free;
1463 }
1464 
1465 /**
1466  * fc_seq_assign() - Assign exchange and sequence for incoming request
1467  * @lport: The local port that received the request
1468  * @fp:    The request frame
1469  *
1470  * On success, the sequence pointer will be returned and also in fr_seq(@fp).
1471  * A reference will be held on the exchange/sequence for the caller, which
1472  * must call fc_seq_release().
1473  */
fc_seq_assign(struct fc_lport * lport,struct fc_frame * fp)1474 struct fc_seq *fc_seq_assign(struct fc_lport *lport, struct fc_frame *fp)
1475 {
1476 	struct fc_exch_mgr_anchor *ema;
1477 
1478 	WARN_ON(lport != fr_dev(fp));
1479 	WARN_ON(fr_seq(fp));
1480 	fr_seq(fp) = NULL;
1481 
1482 	list_for_each_entry(ema, &lport->ema_list, ema_list)
1483 		if ((!ema->match || ema->match(fp)) &&
1484 		    fc_seq_lookup_recip(lport, ema->mp, fp) == FC_RJT_NONE)
1485 			break;
1486 	return fr_seq(fp);
1487 }
1488 EXPORT_SYMBOL(fc_seq_assign);
1489 
1490 /**
1491  * fc_seq_release() - Release the hold
1492  * @sp:    The sequence.
1493  */
fc_seq_release(struct fc_seq * sp)1494 void fc_seq_release(struct fc_seq *sp)
1495 {
1496 	fc_exch_release(fc_seq_exch(sp));
1497 }
1498 EXPORT_SYMBOL(fc_seq_release);
1499 
1500 /**
1501  * fc_exch_recv_req() - Handler for an incoming request
1502  * @lport: The local port that received the request
1503  * @mp:	   The EM that the exchange is on
1504  * @fp:	   The request frame
1505  *
1506  * This is used when the other end is originating the exchange
1507  * and the sequence.
1508  */
fc_exch_recv_req(struct fc_lport * lport,struct fc_exch_mgr * mp,struct fc_frame * fp)1509 static void fc_exch_recv_req(struct fc_lport *lport, struct fc_exch_mgr *mp,
1510 			     struct fc_frame *fp)
1511 {
1512 	struct fc_frame_header *fh = fc_frame_header_get(fp);
1513 	struct fc_seq *sp = NULL;
1514 	struct fc_exch *ep = NULL;
1515 	enum fc_pf_rjt_reason reject;
1516 
1517 	/* We can have the wrong fc_lport at this point with NPIV, which is a
1518 	 * problem now that we know a new exchange needs to be allocated
1519 	 */
1520 	lport = fc_vport_id_lookup(lport, ntoh24(fh->fh_d_id));
1521 	if (!lport) {
1522 		fc_frame_free(fp);
1523 		return;
1524 	}
1525 	fr_dev(fp) = lport;
1526 
1527 	BUG_ON(fr_seq(fp));		/* XXX remove later */
1528 
1529 	/*
1530 	 * If the RX_ID is 0xffff, don't allocate an exchange.
1531 	 * The upper-level protocol may request one later, if needed.
1532 	 */
1533 	if (fh->fh_rx_id == htons(FC_XID_UNKNOWN))
1534 		return fc_lport_recv(lport, fp);
1535 
1536 	reject = fc_seq_lookup_recip(lport, mp, fp);
1537 	if (reject == FC_RJT_NONE) {
1538 		sp = fr_seq(fp);	/* sequence will be held */
1539 		ep = fc_seq_exch(sp);
1540 		fc_seq_send_ack(sp, fp);
1541 		ep->encaps = fr_encaps(fp);
1542 
1543 		/*
1544 		 * Call the receive function.
1545 		 *
1546 		 * The receive function may allocate a new sequence
1547 		 * over the old one, so we shouldn't change the
1548 		 * sequence after this.
1549 		 *
1550 		 * The frame will be freed by the receive function.
1551 		 * If new exch resp handler is valid then call that
1552 		 * first.
1553 		 */
1554 		if (!fc_invoke_resp(ep, sp, fp))
1555 			fc_lport_recv(lport, fp);
1556 		fc_exch_release(ep);	/* release from lookup */
1557 	} else {
1558 		FC_LPORT_DBG(lport, "exch/seq lookup failed: reject %x\n",
1559 			     reject);
1560 		fc_frame_free(fp);
1561 	}
1562 }
1563 
1564 /**
1565  * fc_exch_recv_seq_resp() - Handler for an incoming response where the other
1566  *			     end is the originator of the sequence that is a
1567  *			     response to our initial exchange
1568  * @mp: The EM that the exchange is on
1569  * @fp: The response frame
1570  */
fc_exch_recv_seq_resp(struct fc_exch_mgr * mp,struct fc_frame * fp)1571 static void fc_exch_recv_seq_resp(struct fc_exch_mgr *mp, struct fc_frame *fp)
1572 {
1573 	struct fc_frame_header *fh = fc_frame_header_get(fp);
1574 	struct fc_seq *sp;
1575 	struct fc_exch *ep;
1576 	enum fc_sof sof;
1577 	u32 f_ctl;
1578 	int rc;
1579 
1580 	ep = fc_exch_find(mp, ntohs(fh->fh_ox_id));
1581 	if (!ep) {
1582 		atomic_inc(&mp->stats.xid_not_found);
1583 		goto out;
1584 	}
1585 	if (ep->esb_stat & ESB_ST_COMPLETE) {
1586 		atomic_inc(&mp->stats.xid_not_found);
1587 		goto rel;
1588 	}
1589 	if (ep->rxid == FC_XID_UNKNOWN)
1590 		ep->rxid = ntohs(fh->fh_rx_id);
1591 	if (ep->sid != 0 && ep->sid != ntoh24(fh->fh_d_id)) {
1592 		atomic_inc(&mp->stats.xid_not_found);
1593 		goto rel;
1594 	}
1595 	if (ep->did != ntoh24(fh->fh_s_id) &&
1596 	    ep->did != FC_FID_FLOGI) {
1597 		atomic_inc(&mp->stats.xid_not_found);
1598 		goto rel;
1599 	}
1600 	sof = fr_sof(fp);
1601 	sp = &ep->seq;
1602 	if (fc_sof_is_init(sof)) {
1603 		sp->ssb_stat |= SSB_ST_RESP;
1604 		sp->id = fh->fh_seq_id;
1605 	}
1606 
1607 	f_ctl = ntoh24(fh->fh_f_ctl);
1608 	fr_seq(fp) = sp;
1609 
1610 	spin_lock_bh(&ep->ex_lock);
1611 	if (f_ctl & FC_FC_SEQ_INIT)
1612 		ep->esb_stat |= ESB_ST_SEQ_INIT;
1613 	spin_unlock_bh(&ep->ex_lock);
1614 
1615 	if (fc_sof_needs_ack(sof))
1616 		fc_seq_send_ack(sp, fp);
1617 
1618 	if (fh->fh_type != FC_TYPE_FCP && fr_eof(fp) == FC_EOF_T &&
1619 	    (f_ctl & (FC_FC_LAST_SEQ | FC_FC_END_SEQ)) ==
1620 	    (FC_FC_LAST_SEQ | FC_FC_END_SEQ)) {
1621 		spin_lock_bh(&ep->ex_lock);
1622 		rc = fc_exch_done_locked(ep);
1623 		WARN_ON(fc_seq_exch(sp) != ep);
1624 		spin_unlock_bh(&ep->ex_lock);
1625 		if (!rc) {
1626 			fc_exch_delete(ep);
1627 		} else {
1628 			FC_EXCH_DBG(ep, "ep is completed already,"
1629 					"hence skip calling the resp\n");
1630 			goto skip_resp;
1631 		}
1632 	}
1633 
1634 	/*
1635 	 * Call the receive function.
1636 	 * The sequence is held (has a refcnt) for us,
1637 	 * but not for the receive function.
1638 	 *
1639 	 * The receive function may allocate a new sequence
1640 	 * over the old one, so we shouldn't change the
1641 	 * sequence after this.
1642 	 *
1643 	 * The frame will be freed by the receive function.
1644 	 * If new exch resp handler is valid then call that
1645 	 * first.
1646 	 */
1647 	if (!fc_invoke_resp(ep, sp, fp))
1648 		fc_frame_free(fp);
1649 
1650 skip_resp:
1651 	fc_exch_release(ep);
1652 	return;
1653 rel:
1654 	fc_exch_release(ep);
1655 out:
1656 	fc_frame_free(fp);
1657 }
1658 
1659 /**
1660  * fc_exch_recv_resp() - Handler for a sequence where other end is
1661  *			 responding to our sequence
1662  * @mp: The EM that the exchange is on
1663  * @fp: The response frame
1664  */
fc_exch_recv_resp(struct fc_exch_mgr * mp,struct fc_frame * fp)1665 static void fc_exch_recv_resp(struct fc_exch_mgr *mp, struct fc_frame *fp)
1666 {
1667 	struct fc_seq *sp;
1668 
1669 	sp = fc_seq_lookup_orig(mp, fp);	/* doesn't hold sequence */
1670 
1671 	if (!sp)
1672 		atomic_inc(&mp->stats.xid_not_found);
1673 	else
1674 		atomic_inc(&mp->stats.non_bls_resp);
1675 
1676 	fc_frame_free(fp);
1677 }
1678 
1679 /**
1680  * fc_exch_abts_resp() - Handler for a response to an ABT
1681  * @ep: The exchange that the frame is on
1682  * @fp: The response frame
1683  *
1684  * This response would be to an ABTS cancelling an exchange or sequence.
1685  * The response can be either BA_ACC or BA_RJT
1686  */
fc_exch_abts_resp(struct fc_exch * ep,struct fc_frame * fp)1687 static void fc_exch_abts_resp(struct fc_exch *ep, struct fc_frame *fp)
1688 {
1689 	struct fc_frame_header *fh;
1690 	struct fc_ba_acc *ap;
1691 	struct fc_seq *sp;
1692 	u16 low;
1693 	u16 high;
1694 	int rc = 1, has_rec = 0;
1695 
1696 	fh = fc_frame_header_get(fp);
1697 	FC_EXCH_DBG(ep, "exch: BLS rctl %x - %s\n", fh->fh_r_ctl,
1698 		    fc_exch_rctl_name(fh->fh_r_ctl));
1699 
1700 	if (cancel_delayed_work_sync(&ep->timeout_work)) {
1701 		FC_EXCH_DBG(ep, "Exchange timer canceled due to ABTS response\n");
1702 		fc_exch_release(ep);	/* release from pending timer hold */
1703 		return;
1704 	}
1705 
1706 	spin_lock_bh(&ep->ex_lock);
1707 	switch (fh->fh_r_ctl) {
1708 	case FC_RCTL_BA_ACC:
1709 		ap = fc_frame_payload_get(fp, sizeof(*ap));
1710 		if (!ap)
1711 			break;
1712 
1713 		/*
1714 		 * Decide whether to establish a Recovery Qualifier.
1715 		 * We do this if there is a non-empty SEQ_CNT range and
1716 		 * SEQ_ID is the same as the one we aborted.
1717 		 */
1718 		low = ntohs(ap->ba_low_seq_cnt);
1719 		high = ntohs(ap->ba_high_seq_cnt);
1720 		if ((ep->esb_stat & ESB_ST_REC_QUAL) == 0 &&
1721 		    (ap->ba_seq_id_val != FC_BA_SEQ_ID_VAL ||
1722 		     ap->ba_seq_id == ep->seq_id) && low != high) {
1723 			ep->esb_stat |= ESB_ST_REC_QUAL;
1724 			fc_exch_hold(ep);  /* hold for recovery qualifier */
1725 			has_rec = 1;
1726 		}
1727 		break;
1728 	case FC_RCTL_BA_RJT:
1729 		break;
1730 	default:
1731 		break;
1732 	}
1733 
1734 	/* do we need to do some other checks here. Can we reuse more of
1735 	 * fc_exch_recv_seq_resp
1736 	 */
1737 	sp = &ep->seq;
1738 	/*
1739 	 * do we want to check END_SEQ as well as LAST_SEQ here?
1740 	 */
1741 	if (ep->fh_type != FC_TYPE_FCP &&
1742 	    ntoh24(fh->fh_f_ctl) & FC_FC_LAST_SEQ)
1743 		rc = fc_exch_done_locked(ep);
1744 	spin_unlock_bh(&ep->ex_lock);
1745 
1746 	fc_exch_hold(ep);
1747 	if (!rc)
1748 		fc_exch_delete(ep);
1749 	if (!fc_invoke_resp(ep, sp, fp))
1750 		fc_frame_free(fp);
1751 	if (has_rec)
1752 		fc_exch_timer_set(ep, ep->r_a_tov);
1753 	fc_exch_release(ep);
1754 }
1755 
1756 /**
1757  * fc_exch_recv_bls() - Handler for a BLS sequence
1758  * @mp: The EM that the exchange is on
1759  * @fp: The request frame
1760  *
1761  * The BLS frame is always a sequence initiated by the remote side.
1762  * We may be either the originator or recipient of the exchange.
1763  */
fc_exch_recv_bls(struct fc_exch_mgr * mp,struct fc_frame * fp)1764 static void fc_exch_recv_bls(struct fc_exch_mgr *mp, struct fc_frame *fp)
1765 {
1766 	struct fc_frame_header *fh;
1767 	struct fc_exch *ep;
1768 	u32 f_ctl;
1769 
1770 	fh = fc_frame_header_get(fp);
1771 	f_ctl = ntoh24(fh->fh_f_ctl);
1772 	fr_seq(fp) = NULL;
1773 
1774 	ep = fc_exch_find(mp, (f_ctl & FC_FC_EX_CTX) ?
1775 			  ntohs(fh->fh_ox_id) : ntohs(fh->fh_rx_id));
1776 	if (ep && (f_ctl & FC_FC_SEQ_INIT)) {
1777 		spin_lock_bh(&ep->ex_lock);
1778 		ep->esb_stat |= ESB_ST_SEQ_INIT;
1779 		spin_unlock_bh(&ep->ex_lock);
1780 	}
1781 	if (f_ctl & FC_FC_SEQ_CTX) {
1782 		/*
1783 		 * A response to a sequence we initiated.
1784 		 * This should only be ACKs for class 2 or F.
1785 		 */
1786 		switch (fh->fh_r_ctl) {
1787 		case FC_RCTL_ACK_1:
1788 		case FC_RCTL_ACK_0:
1789 			break;
1790 		default:
1791 			if (ep)
1792 				FC_EXCH_DBG(ep, "BLS rctl %x - %s received\n",
1793 					    fh->fh_r_ctl,
1794 					    fc_exch_rctl_name(fh->fh_r_ctl));
1795 			break;
1796 		}
1797 		fc_frame_free(fp);
1798 	} else {
1799 		switch (fh->fh_r_ctl) {
1800 		case FC_RCTL_BA_RJT:
1801 		case FC_RCTL_BA_ACC:
1802 			if (ep)
1803 				fc_exch_abts_resp(ep, fp);
1804 			else
1805 				fc_frame_free(fp);
1806 			break;
1807 		case FC_RCTL_BA_ABTS:
1808 			if (ep)
1809 				fc_exch_recv_abts(ep, fp);
1810 			else
1811 				fc_frame_free(fp);
1812 			break;
1813 		default:			/* ignore junk */
1814 			fc_frame_free(fp);
1815 			break;
1816 		}
1817 	}
1818 	if (ep)
1819 		fc_exch_release(ep);	/* release hold taken by fc_exch_find */
1820 }
1821 
1822 /**
1823  * fc_seq_ls_acc() - Accept sequence with LS_ACC
1824  * @rx_fp: The received frame, not freed here.
1825  *
1826  * If this fails due to allocation or transmit congestion, assume the
1827  * originator will repeat the sequence.
1828  */
fc_seq_ls_acc(struct fc_frame * rx_fp)1829 static void fc_seq_ls_acc(struct fc_frame *rx_fp)
1830 {
1831 	struct fc_lport *lport;
1832 	struct fc_els_ls_acc *acc;
1833 	struct fc_frame *fp;
1834 	struct fc_seq *sp;
1835 
1836 	lport = fr_dev(rx_fp);
1837 	sp = fr_seq(rx_fp);
1838 	fp = fc_frame_alloc(lport, sizeof(*acc));
1839 	if (!fp) {
1840 		FC_EXCH_DBG(fc_seq_exch(sp),
1841 			    "exch: drop LS_ACC, out of memory\n");
1842 		return;
1843 	}
1844 	acc = fc_frame_payload_get(fp, sizeof(*acc));
1845 	memset(acc, 0, sizeof(*acc));
1846 	acc->la_cmd = ELS_LS_ACC;
1847 	fc_fill_reply_hdr(fp, rx_fp, FC_RCTL_ELS_REP, 0);
1848 	lport->tt.frame_send(lport, fp);
1849 }
1850 
1851 /**
1852  * fc_seq_ls_rjt() - Reject a sequence with ELS LS_RJT
1853  * @rx_fp: The received frame, not freed here.
1854  * @reason: The reason the sequence is being rejected
1855  * @explan: The explanation for the rejection
1856  *
1857  * If this fails due to allocation or transmit congestion, assume the
1858  * originator will repeat the sequence.
1859  */
fc_seq_ls_rjt(struct fc_frame * rx_fp,enum fc_els_rjt_reason reason,enum fc_els_rjt_explan explan)1860 static void fc_seq_ls_rjt(struct fc_frame *rx_fp, enum fc_els_rjt_reason reason,
1861 			  enum fc_els_rjt_explan explan)
1862 {
1863 	struct fc_lport *lport;
1864 	struct fc_els_ls_rjt *rjt;
1865 	struct fc_frame *fp;
1866 	struct fc_seq *sp;
1867 
1868 	lport = fr_dev(rx_fp);
1869 	sp = fr_seq(rx_fp);
1870 	fp = fc_frame_alloc(lport, sizeof(*rjt));
1871 	if (!fp) {
1872 		FC_EXCH_DBG(fc_seq_exch(sp),
1873 			    "exch: drop LS_ACC, out of memory\n");
1874 		return;
1875 	}
1876 	rjt = fc_frame_payload_get(fp, sizeof(*rjt));
1877 	memset(rjt, 0, sizeof(*rjt));
1878 	rjt->er_cmd = ELS_LS_RJT;
1879 	rjt->er_reason = reason;
1880 	rjt->er_explan = explan;
1881 	fc_fill_reply_hdr(fp, rx_fp, FC_RCTL_ELS_REP, 0);
1882 	lport->tt.frame_send(lport, fp);
1883 }
1884 
1885 /**
1886  * fc_exch_reset() - Reset an exchange
1887  * @ep: The exchange to be reset
1888  *
1889  * Note: May sleep if invoked from outside a response handler.
1890  */
fc_exch_reset(struct fc_exch * ep)1891 static void fc_exch_reset(struct fc_exch *ep)
1892 {
1893 	struct fc_seq *sp;
1894 	int rc = 1;
1895 
1896 	spin_lock_bh(&ep->ex_lock);
1897 	ep->state |= FC_EX_RST_CLEANUP;
1898 	fc_exch_timer_cancel(ep);
1899 	if (ep->esb_stat & ESB_ST_REC_QUAL)
1900 		atomic_dec(&ep->ex_refcnt);	/* drop hold for rec_qual */
1901 	ep->esb_stat &= ~ESB_ST_REC_QUAL;
1902 	sp = &ep->seq;
1903 	rc = fc_exch_done_locked(ep);
1904 	spin_unlock_bh(&ep->ex_lock);
1905 
1906 	fc_exch_hold(ep);
1907 
1908 	if (!rc) {
1909 		fc_exch_delete(ep);
1910 	} else {
1911 		FC_EXCH_DBG(ep, "ep is completed already,"
1912 				"hence skip calling the resp\n");
1913 		goto skip_resp;
1914 	}
1915 
1916 	fc_invoke_resp(ep, sp, ERR_PTR(-FC_EX_CLOSED));
1917 skip_resp:
1918 	fc_seq_set_resp(sp, NULL, ep->arg);
1919 	fc_exch_release(ep);
1920 }
1921 
1922 /**
1923  * fc_exch_pool_reset() - Reset a per cpu exchange pool
1924  * @lport: The local port that the exchange pool is on
1925  * @pool:  The exchange pool to be reset
1926  * @sid:   The source ID
1927  * @did:   The destination ID
1928  *
1929  * Resets a per cpu exches pool, releasing all of its sequences
1930  * and exchanges. If sid is non-zero then reset only exchanges
1931  * we sourced from the local port's FID. If did is non-zero then
1932  * only reset exchanges destined for the local port's FID.
1933  */
fc_exch_pool_reset(struct fc_lport * lport,struct fc_exch_pool * pool,u32 sid,u32 did)1934 static void fc_exch_pool_reset(struct fc_lport *lport,
1935 			       struct fc_exch_pool *pool,
1936 			       u32 sid, u32 did)
1937 {
1938 	struct fc_exch *ep;
1939 	struct fc_exch *next;
1940 
1941 	spin_lock_bh(&pool->lock);
1942 restart:
1943 	list_for_each_entry_safe(ep, next, &pool->ex_list, ex_list) {
1944 		if ((lport == ep->lp) &&
1945 		    (sid == 0 || sid == ep->sid) &&
1946 		    (did == 0 || did == ep->did)) {
1947 			fc_exch_hold(ep);
1948 			spin_unlock_bh(&pool->lock);
1949 
1950 			fc_exch_reset(ep);
1951 
1952 			fc_exch_release(ep);
1953 			spin_lock_bh(&pool->lock);
1954 
1955 			/*
1956 			 * must restart loop incase while lock
1957 			 * was down multiple eps were released.
1958 			 */
1959 			goto restart;
1960 		}
1961 	}
1962 	pool->next_index = 0;
1963 	pool->left = FC_XID_UNKNOWN;
1964 	pool->right = FC_XID_UNKNOWN;
1965 	spin_unlock_bh(&pool->lock);
1966 }
1967 
1968 /**
1969  * fc_exch_mgr_reset() - Reset all EMs of a local port
1970  * @lport: The local port whose EMs are to be reset
1971  * @sid:   The source ID
1972  * @did:   The destination ID
1973  *
1974  * Reset all EMs associated with a given local port. Release all
1975  * sequences and exchanges. If sid is non-zero then reset only the
1976  * exchanges sent from the local port's FID. If did is non-zero then
1977  * reset only exchanges destined for the local port's FID.
1978  */
fc_exch_mgr_reset(struct fc_lport * lport,u32 sid,u32 did)1979 void fc_exch_mgr_reset(struct fc_lport *lport, u32 sid, u32 did)
1980 {
1981 	struct fc_exch_mgr_anchor *ema;
1982 	unsigned int cpu;
1983 
1984 	list_for_each_entry(ema, &lport->ema_list, ema_list) {
1985 		for_each_possible_cpu(cpu)
1986 			fc_exch_pool_reset(lport,
1987 					   per_cpu_ptr(ema->mp->pool, cpu),
1988 					   sid, did);
1989 	}
1990 }
1991 EXPORT_SYMBOL(fc_exch_mgr_reset);
1992 
1993 /**
1994  * fc_exch_lookup() - find an exchange
1995  * @lport: The local port
1996  * @xid: The exchange ID
1997  *
1998  * Returns exchange pointer with hold for caller, or NULL if not found.
1999  */
fc_exch_lookup(struct fc_lport * lport,u32 xid)2000 static struct fc_exch *fc_exch_lookup(struct fc_lport *lport, u32 xid)
2001 {
2002 	struct fc_exch_mgr_anchor *ema;
2003 
2004 	list_for_each_entry(ema, &lport->ema_list, ema_list)
2005 		if (ema->mp->min_xid <= xid && xid <= ema->mp->max_xid)
2006 			return fc_exch_find(ema->mp, xid);
2007 	return NULL;
2008 }
2009 
2010 /**
2011  * fc_exch_els_rec() - Handler for ELS REC (Read Exchange Concise) requests
2012  * @rfp: The REC frame, not freed here.
2013  *
2014  * Note that the requesting port may be different than the S_ID in the request.
2015  */
fc_exch_els_rec(struct fc_frame * rfp)2016 static void fc_exch_els_rec(struct fc_frame *rfp)
2017 {
2018 	struct fc_lport *lport;
2019 	struct fc_frame *fp;
2020 	struct fc_exch *ep;
2021 	struct fc_els_rec *rp;
2022 	struct fc_els_rec_acc *acc;
2023 	enum fc_els_rjt_reason reason = ELS_RJT_LOGIC;
2024 	enum fc_els_rjt_explan explan;
2025 	u32 sid;
2026 	u16 xid, rxid, oxid;
2027 
2028 	lport = fr_dev(rfp);
2029 	rp = fc_frame_payload_get(rfp, sizeof(*rp));
2030 	explan = ELS_EXPL_INV_LEN;
2031 	if (!rp)
2032 		goto reject;
2033 	sid = ntoh24(rp->rec_s_id);
2034 	rxid = ntohs(rp->rec_rx_id);
2035 	oxid = ntohs(rp->rec_ox_id);
2036 
2037 	explan = ELS_EXPL_OXID_RXID;
2038 	if (sid == fc_host_port_id(lport->host))
2039 		xid = oxid;
2040 	else
2041 		xid = rxid;
2042 	if (xid == FC_XID_UNKNOWN) {
2043 		FC_LPORT_DBG(lport,
2044 			     "REC request from %x: invalid rxid %x oxid %x\n",
2045 			     sid, rxid, oxid);
2046 		goto reject;
2047 	}
2048 	ep = fc_exch_lookup(lport, xid);
2049 	if (!ep) {
2050 		FC_LPORT_DBG(lport,
2051 			     "REC request from %x: rxid %x oxid %x not found\n",
2052 			     sid, rxid, oxid);
2053 		goto reject;
2054 	}
2055 	FC_EXCH_DBG(ep, "REC request from %x: rxid %x oxid %x\n",
2056 		    sid, rxid, oxid);
2057 	if (ep->oid != sid || oxid != ep->oxid)
2058 		goto rel;
2059 	if (rxid != FC_XID_UNKNOWN && rxid != ep->rxid)
2060 		goto rel;
2061 	fp = fc_frame_alloc(lport, sizeof(*acc));
2062 	if (!fp) {
2063 		FC_EXCH_DBG(ep, "Drop REC request, out of memory\n");
2064 		goto out;
2065 	}
2066 
2067 	acc = fc_frame_payload_get(fp, sizeof(*acc));
2068 	memset(acc, 0, sizeof(*acc));
2069 	acc->reca_cmd = ELS_LS_ACC;
2070 	acc->reca_ox_id = rp->rec_ox_id;
2071 	memcpy(acc->reca_ofid, rp->rec_s_id, 3);
2072 	acc->reca_rx_id = htons(ep->rxid);
2073 	if (ep->sid == ep->oid)
2074 		hton24(acc->reca_rfid, ep->did);
2075 	else
2076 		hton24(acc->reca_rfid, ep->sid);
2077 	acc->reca_fc4value = htonl(ep->seq.rec_data);
2078 	acc->reca_e_stat = htonl(ep->esb_stat & (ESB_ST_RESP |
2079 						 ESB_ST_SEQ_INIT |
2080 						 ESB_ST_COMPLETE));
2081 	fc_fill_reply_hdr(fp, rfp, FC_RCTL_ELS_REP, 0);
2082 	lport->tt.frame_send(lport, fp);
2083 out:
2084 	fc_exch_release(ep);
2085 	return;
2086 
2087 rel:
2088 	fc_exch_release(ep);
2089 reject:
2090 	fc_seq_ls_rjt(rfp, reason, explan);
2091 }
2092 
2093 /**
2094  * fc_exch_rrq_resp() - Handler for RRQ responses
2095  * @sp:	 The sequence that the RRQ is on
2096  * @fp:	 The RRQ frame
2097  * @arg: The exchange that the RRQ is on
2098  *
2099  * TODO: fix error handler.
2100  */
fc_exch_rrq_resp(struct fc_seq * sp,struct fc_frame * fp,void * arg)2101 static void fc_exch_rrq_resp(struct fc_seq *sp, struct fc_frame *fp, void *arg)
2102 {
2103 	struct fc_exch *aborted_ep = arg;
2104 	unsigned int op;
2105 
2106 	if (IS_ERR(fp)) {
2107 		int err = PTR_ERR(fp);
2108 
2109 		if (err == -FC_EX_CLOSED || err == -FC_EX_TIMEOUT)
2110 			goto cleanup;
2111 		FC_EXCH_DBG(aborted_ep, "Cannot process RRQ, "
2112 			    "frame error %d\n", err);
2113 		return;
2114 	}
2115 
2116 	op = fc_frame_payload_op(fp);
2117 	fc_frame_free(fp);
2118 
2119 	switch (op) {
2120 	case ELS_LS_RJT:
2121 		FC_EXCH_DBG(aborted_ep, "LS_RJT for RRQ\n");
2122 		fallthrough;
2123 	case ELS_LS_ACC:
2124 		goto cleanup;
2125 	default:
2126 		FC_EXCH_DBG(aborted_ep, "unexpected response op %x for RRQ\n",
2127 			    op);
2128 		return;
2129 	}
2130 
2131 cleanup:
2132 	fc_exch_done(&aborted_ep->seq);
2133 	/* drop hold for rec qual */
2134 	fc_exch_release(aborted_ep);
2135 }
2136 
2137 
2138 /**
2139  * fc_exch_seq_send() - Send a frame using a new exchange and sequence
2140  * @lport:	The local port to send the frame on
2141  * @fp:		The frame to be sent
2142  * @resp:	The response handler for this request
2143  * @destructor: The destructor for the exchange
2144  * @arg:	The argument to be passed to the response handler
2145  * @timer_msec: The timeout period for the exchange
2146  *
2147  * The exchange response handler is set in this routine to resp()
2148  * function pointer. It can be called in two scenarios: if a timeout
2149  * occurs or if a response frame is received for the exchange. The
2150  * fc_frame pointer in response handler will also indicate timeout
2151  * as error using IS_ERR related macros.
2152  *
2153  * The exchange destructor handler is also set in this routine.
2154  * The destructor handler is invoked by EM layer when exchange
2155  * is about to free, this can be used by caller to free its
2156  * resources along with exchange free.
2157  *
2158  * The arg is passed back to resp and destructor handler.
2159  *
2160  * The timeout value (in msec) for an exchange is set if non zero
2161  * timer_msec argument is specified. The timer is canceled when
2162  * it fires or when the exchange is done. The exchange timeout handler
2163  * is registered by EM layer.
2164  *
2165  * The frame pointer with some of the header's fields must be
2166  * filled before calling this routine, those fields are:
2167  *
2168  * - routing control
2169  * - FC port did
2170  * - FC port sid
2171  * - FC header type
2172  * - frame control
2173  * - parameter or relative offset
2174  */
fc_exch_seq_send(struct fc_lport * lport,struct fc_frame * fp,void (* resp)(struct fc_seq *,struct fc_frame * fp,void * arg),void (* destructor)(struct fc_seq *,void *),void * arg,u32 timer_msec)2175 struct fc_seq *fc_exch_seq_send(struct fc_lport *lport,
2176 				struct fc_frame *fp,
2177 				void (*resp)(struct fc_seq *,
2178 					     struct fc_frame *fp,
2179 					     void *arg),
2180 				void (*destructor)(struct fc_seq *, void *),
2181 				void *arg, u32 timer_msec)
2182 {
2183 	struct fc_exch *ep;
2184 	struct fc_seq *sp = NULL;
2185 	struct fc_frame_header *fh;
2186 	struct fc_fcp_pkt *fsp = NULL;
2187 	int rc = 1;
2188 
2189 	ep = fc_exch_alloc(lport, fp);
2190 	if (!ep) {
2191 		fc_frame_free(fp);
2192 		return NULL;
2193 	}
2194 	ep->esb_stat |= ESB_ST_SEQ_INIT;
2195 	fh = fc_frame_header_get(fp);
2196 	fc_exch_set_addr(ep, ntoh24(fh->fh_s_id), ntoh24(fh->fh_d_id));
2197 	ep->resp = resp;
2198 	ep->destructor = destructor;
2199 	ep->arg = arg;
2200 	ep->r_a_tov = lport->r_a_tov;
2201 	ep->lp = lport;
2202 	sp = &ep->seq;
2203 
2204 	ep->fh_type = fh->fh_type; /* save for possbile timeout handling */
2205 	ep->f_ctl = ntoh24(fh->fh_f_ctl);
2206 	fc_exch_setup_hdr(ep, fp, ep->f_ctl);
2207 	sp->cnt++;
2208 
2209 	if (ep->xid <= lport->lro_xid && fh->fh_r_ctl == FC_RCTL_DD_UNSOL_CMD) {
2210 		fsp = fr_fsp(fp);
2211 		fc_fcp_ddp_setup(fr_fsp(fp), ep->xid);
2212 	}
2213 
2214 	if (unlikely(lport->tt.frame_send(lport, fp)))
2215 		goto err;
2216 
2217 	if (timer_msec)
2218 		fc_exch_timer_set_locked(ep, timer_msec);
2219 	ep->f_ctl &= ~FC_FC_FIRST_SEQ;	/* not first seq */
2220 
2221 	if (ep->f_ctl & FC_FC_SEQ_INIT)
2222 		ep->esb_stat &= ~ESB_ST_SEQ_INIT;
2223 	spin_unlock_bh(&ep->ex_lock);
2224 	return sp;
2225 err:
2226 	if (fsp)
2227 		fc_fcp_ddp_done(fsp);
2228 	rc = fc_exch_done_locked(ep);
2229 	spin_unlock_bh(&ep->ex_lock);
2230 	if (!rc)
2231 		fc_exch_delete(ep);
2232 	return NULL;
2233 }
2234 EXPORT_SYMBOL(fc_exch_seq_send);
2235 
2236 /**
2237  * fc_exch_rrq() - Send an ELS RRQ (Reinstate Recovery Qualifier) command
2238  * @ep: The exchange to send the RRQ on
2239  *
2240  * This tells the remote port to stop blocking the use of
2241  * the exchange and the seq_cnt range.
2242  */
fc_exch_rrq(struct fc_exch * ep)2243 static void fc_exch_rrq(struct fc_exch *ep)
2244 {
2245 	struct fc_lport *lport;
2246 	struct fc_els_rrq *rrq;
2247 	struct fc_frame *fp;
2248 	u32 did;
2249 
2250 	lport = ep->lp;
2251 
2252 	fp = fc_frame_alloc(lport, sizeof(*rrq));
2253 	if (!fp)
2254 		goto retry;
2255 
2256 	rrq = fc_frame_payload_get(fp, sizeof(*rrq));
2257 	memset(rrq, 0, sizeof(*rrq));
2258 	rrq->rrq_cmd = ELS_RRQ;
2259 	hton24(rrq->rrq_s_id, ep->sid);
2260 	rrq->rrq_ox_id = htons(ep->oxid);
2261 	rrq->rrq_rx_id = htons(ep->rxid);
2262 
2263 	did = ep->did;
2264 	if (ep->esb_stat & ESB_ST_RESP)
2265 		did = ep->sid;
2266 
2267 	fc_fill_fc_hdr(fp, FC_RCTL_ELS_REQ, did,
2268 		       lport->port_id, FC_TYPE_ELS,
2269 		       FC_FC_FIRST_SEQ | FC_FC_END_SEQ | FC_FC_SEQ_INIT, 0);
2270 
2271 	if (fc_exch_seq_send(lport, fp, fc_exch_rrq_resp, NULL, ep,
2272 			     lport->e_d_tov))
2273 		return;
2274 
2275 retry:
2276 	FC_EXCH_DBG(ep, "exch: RRQ send failed\n");
2277 	spin_lock_bh(&ep->ex_lock);
2278 	if (ep->state & (FC_EX_RST_CLEANUP | FC_EX_DONE)) {
2279 		spin_unlock_bh(&ep->ex_lock);
2280 		/* drop hold for rec qual */
2281 		fc_exch_release(ep);
2282 		return;
2283 	}
2284 	ep->esb_stat |= ESB_ST_REC_QUAL;
2285 	fc_exch_timer_set_locked(ep, ep->r_a_tov);
2286 	spin_unlock_bh(&ep->ex_lock);
2287 }
2288 
2289 /**
2290  * fc_exch_els_rrq() - Handler for ELS RRQ (Reset Recovery Qualifier) requests
2291  * @fp: The RRQ frame, not freed here.
2292  */
fc_exch_els_rrq(struct fc_frame * fp)2293 static void fc_exch_els_rrq(struct fc_frame *fp)
2294 {
2295 	struct fc_lport *lport;
2296 	struct fc_exch *ep = NULL;	/* request or subject exchange */
2297 	struct fc_els_rrq *rp;
2298 	u32 sid;
2299 	u16 xid;
2300 	enum fc_els_rjt_explan explan;
2301 
2302 	lport = fr_dev(fp);
2303 	rp = fc_frame_payload_get(fp, sizeof(*rp));
2304 	explan = ELS_EXPL_INV_LEN;
2305 	if (!rp)
2306 		goto reject;
2307 
2308 	/*
2309 	 * lookup subject exchange.
2310 	 */
2311 	sid = ntoh24(rp->rrq_s_id);		/* subject source */
2312 	xid = fc_host_port_id(lport->host) == sid ?
2313 			ntohs(rp->rrq_ox_id) : ntohs(rp->rrq_rx_id);
2314 	ep = fc_exch_lookup(lport, xid);
2315 	explan = ELS_EXPL_OXID_RXID;
2316 	if (!ep)
2317 		goto reject;
2318 	spin_lock_bh(&ep->ex_lock);
2319 	FC_EXCH_DBG(ep, "RRQ request from %x: xid %x rxid %x oxid %x\n",
2320 		    sid, xid, ntohs(rp->rrq_rx_id), ntohs(rp->rrq_ox_id));
2321 	if (ep->oxid != ntohs(rp->rrq_ox_id))
2322 		goto unlock_reject;
2323 	if (ep->rxid != ntohs(rp->rrq_rx_id) &&
2324 	    ep->rxid != FC_XID_UNKNOWN)
2325 		goto unlock_reject;
2326 	explan = ELS_EXPL_SID;
2327 	if (ep->sid != sid)
2328 		goto unlock_reject;
2329 
2330 	/*
2331 	 * Clear Recovery Qualifier state, and cancel timer if complete.
2332 	 */
2333 	if (ep->esb_stat & ESB_ST_REC_QUAL) {
2334 		ep->esb_stat &= ~ESB_ST_REC_QUAL;
2335 		atomic_dec(&ep->ex_refcnt);	/* drop hold for rec qual */
2336 	}
2337 	if (ep->esb_stat & ESB_ST_COMPLETE)
2338 		fc_exch_timer_cancel(ep);
2339 
2340 	spin_unlock_bh(&ep->ex_lock);
2341 
2342 	/*
2343 	 * Send LS_ACC.
2344 	 */
2345 	fc_seq_ls_acc(fp);
2346 	goto out;
2347 
2348 unlock_reject:
2349 	spin_unlock_bh(&ep->ex_lock);
2350 reject:
2351 	fc_seq_ls_rjt(fp, ELS_RJT_LOGIC, explan);
2352 out:
2353 	if (ep)
2354 		fc_exch_release(ep);	/* drop hold from fc_exch_find */
2355 }
2356 
2357 /**
2358  * fc_exch_update_stats() - update exches stats to lport
2359  * @lport: The local port to update exchange manager stats
2360  */
fc_exch_update_stats(struct fc_lport * lport)2361 void fc_exch_update_stats(struct fc_lport *lport)
2362 {
2363 	struct fc_host_statistics *st;
2364 	struct fc_exch_mgr_anchor *ema;
2365 	struct fc_exch_mgr *mp;
2366 
2367 	st = &lport->host_stats;
2368 
2369 	list_for_each_entry(ema, &lport->ema_list, ema_list) {
2370 		mp = ema->mp;
2371 		st->fc_no_free_exch += atomic_read(&mp->stats.no_free_exch);
2372 		st->fc_no_free_exch_xid +=
2373 				atomic_read(&mp->stats.no_free_exch_xid);
2374 		st->fc_xid_not_found += atomic_read(&mp->stats.xid_not_found);
2375 		st->fc_xid_busy += atomic_read(&mp->stats.xid_busy);
2376 		st->fc_seq_not_found += atomic_read(&mp->stats.seq_not_found);
2377 		st->fc_non_bls_resp += atomic_read(&mp->stats.non_bls_resp);
2378 	}
2379 }
2380 EXPORT_SYMBOL(fc_exch_update_stats);
2381 
2382 /**
2383  * fc_exch_mgr_add() - Add an exchange manager to a local port's list of EMs
2384  * @lport: The local port to add the exchange manager to
2385  * @mp:	   The exchange manager to be added to the local port
2386  * @match: The match routine that indicates when this EM should be used
2387  */
fc_exch_mgr_add(struct fc_lport * lport,struct fc_exch_mgr * mp,bool (* match)(struct fc_frame *))2388 struct fc_exch_mgr_anchor *fc_exch_mgr_add(struct fc_lport *lport,
2389 					   struct fc_exch_mgr *mp,
2390 					   bool (*match)(struct fc_frame *))
2391 {
2392 	struct fc_exch_mgr_anchor *ema;
2393 
2394 	ema = kmalloc(sizeof(*ema), GFP_ATOMIC);
2395 	if (!ema)
2396 		return ema;
2397 
2398 	ema->mp = mp;
2399 	ema->match = match;
2400 	/* add EM anchor to EM anchors list */
2401 	list_add_tail(&ema->ema_list, &lport->ema_list);
2402 	kref_get(&mp->kref);
2403 	return ema;
2404 }
2405 EXPORT_SYMBOL(fc_exch_mgr_add);
2406 
2407 /**
2408  * fc_exch_mgr_destroy() - Destroy an exchange manager
2409  * @kref: The reference to the EM to be destroyed
2410  */
fc_exch_mgr_destroy(struct kref * kref)2411 static void fc_exch_mgr_destroy(struct kref *kref)
2412 {
2413 	struct fc_exch_mgr *mp = container_of(kref, struct fc_exch_mgr, kref);
2414 
2415 	mempool_destroy(mp->ep_pool);
2416 	free_percpu(mp->pool);
2417 	kfree(mp);
2418 }
2419 
2420 /**
2421  * fc_exch_mgr_del() - Delete an EM from a local port's list
2422  * @ema: The exchange manager anchor identifying the EM to be deleted
2423  */
fc_exch_mgr_del(struct fc_exch_mgr_anchor * ema)2424 void fc_exch_mgr_del(struct fc_exch_mgr_anchor *ema)
2425 {
2426 	/* remove EM anchor from EM anchors list */
2427 	list_del(&ema->ema_list);
2428 	kref_put(&ema->mp->kref, fc_exch_mgr_destroy);
2429 	kfree(ema);
2430 }
2431 EXPORT_SYMBOL(fc_exch_mgr_del);
2432 
2433 /**
2434  * fc_exch_mgr_list_clone() - Share all exchange manager objects
2435  * @src: Source lport to clone exchange managers from
2436  * @dst: New lport that takes references to all the exchange managers
2437  */
fc_exch_mgr_list_clone(struct fc_lport * src,struct fc_lport * dst)2438 int fc_exch_mgr_list_clone(struct fc_lport *src, struct fc_lport *dst)
2439 {
2440 	struct fc_exch_mgr_anchor *ema, *tmp;
2441 
2442 	list_for_each_entry(ema, &src->ema_list, ema_list) {
2443 		if (!fc_exch_mgr_add(dst, ema->mp, ema->match))
2444 			goto err;
2445 	}
2446 	return 0;
2447 err:
2448 	list_for_each_entry_safe(ema, tmp, &dst->ema_list, ema_list)
2449 		fc_exch_mgr_del(ema);
2450 	return -ENOMEM;
2451 }
2452 EXPORT_SYMBOL(fc_exch_mgr_list_clone);
2453 
2454 /**
2455  * fc_exch_mgr_alloc() - Allocate an exchange manager
2456  * @lport:   The local port that the new EM will be associated with
2457  * @class:   The default FC class for new exchanges
2458  * @min_xid: The minimum XID for exchanges from the new EM
2459  * @max_xid: The maximum XID for exchanges from the new EM
2460  * @match:   The match routine for the new EM
2461  */
fc_exch_mgr_alloc(struct fc_lport * lport,enum fc_class class,u16 min_xid,u16 max_xid,bool (* match)(struct fc_frame *))2462 struct fc_exch_mgr *fc_exch_mgr_alloc(struct fc_lport *lport,
2463 				      enum fc_class class,
2464 				      u16 min_xid, u16 max_xid,
2465 				      bool (*match)(struct fc_frame *))
2466 {
2467 	struct fc_exch_mgr *mp;
2468 	u16 pool_exch_range;
2469 	size_t pool_size;
2470 	unsigned int cpu;
2471 	struct fc_exch_pool *pool;
2472 
2473 	if (max_xid <= min_xid || max_xid == FC_XID_UNKNOWN ||
2474 	    (min_xid & fc_cpu_mask) != 0) {
2475 		FC_LPORT_DBG(lport, "Invalid min_xid 0x:%x and max_xid 0x:%x\n",
2476 			     min_xid, max_xid);
2477 		return NULL;
2478 	}
2479 
2480 	/*
2481 	 * allocate memory for EM
2482 	 */
2483 	mp = kzalloc(sizeof(struct fc_exch_mgr), GFP_ATOMIC);
2484 	if (!mp)
2485 		return NULL;
2486 
2487 	mp->class = class;
2488 	mp->lport = lport;
2489 	/* adjust em exch xid range for offload */
2490 	mp->min_xid = min_xid;
2491 
2492        /* reduce range so per cpu pool fits into PCPU_MIN_UNIT_SIZE pool */
2493 	pool_exch_range = (PCPU_MIN_UNIT_SIZE - sizeof(*pool)) /
2494 		sizeof(struct fc_exch *);
2495 	if ((max_xid - min_xid + 1) / (fc_cpu_mask + 1) > pool_exch_range) {
2496 		mp->max_xid = pool_exch_range * (fc_cpu_mask + 1) +
2497 			min_xid - 1;
2498 	} else {
2499 		mp->max_xid = max_xid;
2500 		pool_exch_range = (mp->max_xid - mp->min_xid + 1) /
2501 			(fc_cpu_mask + 1);
2502 	}
2503 
2504 	mp->ep_pool = mempool_create_slab_pool(2, fc_em_cachep);
2505 	if (!mp->ep_pool)
2506 		goto free_mp;
2507 
2508 	/*
2509 	 * Setup per cpu exch pool with entire exchange id range equally
2510 	 * divided across all cpus. The exch pointers array memory is
2511 	 * allocated for exch range per pool.
2512 	 */
2513 	mp->pool_max_index = pool_exch_range - 1;
2514 
2515 	/*
2516 	 * Allocate and initialize per cpu exch pool
2517 	 */
2518 	pool_size = sizeof(*pool) + pool_exch_range * sizeof(struct fc_exch *);
2519 	mp->pool = __alloc_percpu(pool_size, __alignof__(struct fc_exch_pool));
2520 	if (!mp->pool)
2521 		goto free_mempool;
2522 	for_each_possible_cpu(cpu) {
2523 		pool = per_cpu_ptr(mp->pool, cpu);
2524 		pool->next_index = 0;
2525 		pool->left = FC_XID_UNKNOWN;
2526 		pool->right = FC_XID_UNKNOWN;
2527 		spin_lock_init(&pool->lock);
2528 		INIT_LIST_HEAD(&pool->ex_list);
2529 	}
2530 
2531 	kref_init(&mp->kref);
2532 	if (!fc_exch_mgr_add(lport, mp, match)) {
2533 		free_percpu(mp->pool);
2534 		goto free_mempool;
2535 	}
2536 
2537 	/*
2538 	 * Above kref_init() sets mp->kref to 1 and then
2539 	 * call to fc_exch_mgr_add incremented mp->kref again,
2540 	 * so adjust that extra increment.
2541 	 */
2542 	kref_put(&mp->kref, fc_exch_mgr_destroy);
2543 	return mp;
2544 
2545 free_mempool:
2546 	mempool_destroy(mp->ep_pool);
2547 free_mp:
2548 	kfree(mp);
2549 	return NULL;
2550 }
2551 EXPORT_SYMBOL(fc_exch_mgr_alloc);
2552 
2553 /**
2554  * fc_exch_mgr_free() - Free all exchange managers on a local port
2555  * @lport: The local port whose EMs are to be freed
2556  */
fc_exch_mgr_free(struct fc_lport * lport)2557 void fc_exch_mgr_free(struct fc_lport *lport)
2558 {
2559 	struct fc_exch_mgr_anchor *ema, *next;
2560 
2561 	flush_workqueue(fc_exch_workqueue);
2562 	list_for_each_entry_safe(ema, next, &lport->ema_list, ema_list)
2563 		fc_exch_mgr_del(ema);
2564 }
2565 EXPORT_SYMBOL(fc_exch_mgr_free);
2566 
2567 /**
2568  * fc_find_ema() - Lookup and return appropriate Exchange Manager Anchor depending
2569  * upon 'xid'.
2570  * @f_ctl: f_ctl
2571  * @lport: The local port the frame was received on
2572  * @fh: The received frame header
2573  */
fc_find_ema(u32 f_ctl,struct fc_lport * lport,struct fc_frame_header * fh)2574 static struct fc_exch_mgr_anchor *fc_find_ema(u32 f_ctl,
2575 					      struct fc_lport *lport,
2576 					      struct fc_frame_header *fh)
2577 {
2578 	struct fc_exch_mgr_anchor *ema;
2579 	u16 xid;
2580 
2581 	if (f_ctl & FC_FC_EX_CTX)
2582 		xid = ntohs(fh->fh_ox_id);
2583 	else {
2584 		xid = ntohs(fh->fh_rx_id);
2585 		if (xid == FC_XID_UNKNOWN)
2586 			return list_entry(lport->ema_list.prev,
2587 					  typeof(*ema), ema_list);
2588 	}
2589 
2590 	list_for_each_entry(ema, &lport->ema_list, ema_list) {
2591 		if ((xid >= ema->mp->min_xid) &&
2592 		    (xid <= ema->mp->max_xid))
2593 			return ema;
2594 	}
2595 	return NULL;
2596 }
2597 /**
2598  * fc_exch_recv() - Handler for received frames
2599  * @lport: The local port the frame was received on
2600  * @fp:	The received frame
2601  */
fc_exch_recv(struct fc_lport * lport,struct fc_frame * fp)2602 void fc_exch_recv(struct fc_lport *lport, struct fc_frame *fp)
2603 {
2604 	struct fc_frame_header *fh = fc_frame_header_get(fp);
2605 	struct fc_exch_mgr_anchor *ema;
2606 	u32 f_ctl;
2607 
2608 	/* lport lock ? */
2609 	if (!lport || lport->state == LPORT_ST_DISABLED) {
2610 		FC_LIBFC_DBG("Receiving frames for an lport that "
2611 			     "has not been initialized correctly\n");
2612 		fc_frame_free(fp);
2613 		return;
2614 	}
2615 
2616 	f_ctl = ntoh24(fh->fh_f_ctl);
2617 	ema = fc_find_ema(f_ctl, lport, fh);
2618 	if (!ema) {
2619 		FC_LPORT_DBG(lport, "Unable to find Exchange Manager Anchor,"
2620 				    "fc_ctl <0x%x>, xid <0x%x>\n",
2621 				     f_ctl,
2622 				     (f_ctl & FC_FC_EX_CTX) ?
2623 				     ntohs(fh->fh_ox_id) :
2624 				     ntohs(fh->fh_rx_id));
2625 		fc_frame_free(fp);
2626 		return;
2627 	}
2628 
2629 	/*
2630 	 * If frame is marked invalid, just drop it.
2631 	 */
2632 	switch (fr_eof(fp)) {
2633 	case FC_EOF_T:
2634 		if (f_ctl & FC_FC_END_SEQ)
2635 			skb_trim(fp_skb(fp), fr_len(fp) - FC_FC_FILL(f_ctl));
2636 		fallthrough;
2637 	case FC_EOF_N:
2638 		if (fh->fh_type == FC_TYPE_BLS)
2639 			fc_exch_recv_bls(ema->mp, fp);
2640 		else if ((f_ctl & (FC_FC_EX_CTX | FC_FC_SEQ_CTX)) ==
2641 			 FC_FC_EX_CTX)
2642 			fc_exch_recv_seq_resp(ema->mp, fp);
2643 		else if (f_ctl & FC_FC_SEQ_CTX)
2644 			fc_exch_recv_resp(ema->mp, fp);
2645 		else	/* no EX_CTX and no SEQ_CTX */
2646 			fc_exch_recv_req(lport, ema->mp, fp);
2647 		break;
2648 	default:
2649 		FC_LPORT_DBG(lport, "dropping invalid frame (eof %x)",
2650 			     fr_eof(fp));
2651 		fc_frame_free(fp);
2652 	}
2653 }
2654 EXPORT_SYMBOL(fc_exch_recv);
2655 
2656 /**
2657  * fc_exch_init() - Initialize the exchange layer for a local port
2658  * @lport: The local port to initialize the exchange layer for
2659  */
fc_exch_init(struct fc_lport * lport)2660 int fc_exch_init(struct fc_lport *lport)
2661 {
2662 	if (!lport->tt.exch_mgr_reset)
2663 		lport->tt.exch_mgr_reset = fc_exch_mgr_reset;
2664 
2665 	return 0;
2666 }
2667 EXPORT_SYMBOL(fc_exch_init);
2668 
2669 /**
2670  * fc_setup_exch_mgr() - Setup an exchange manager
2671  */
fc_setup_exch_mgr(void)2672 int fc_setup_exch_mgr(void)
2673 {
2674 	fc_em_cachep = kmem_cache_create("libfc_em", sizeof(struct fc_exch),
2675 					 0, SLAB_HWCACHE_ALIGN, NULL);
2676 	if (!fc_em_cachep)
2677 		return -ENOMEM;
2678 
2679 	/*
2680 	 * Initialize fc_cpu_mask and fc_cpu_order. The
2681 	 * fc_cpu_mask is set for nr_cpu_ids rounded up
2682 	 * to order of 2's * power and order is stored
2683 	 * in fc_cpu_order as this is later required in
2684 	 * mapping between an exch id and exch array index
2685 	 * in per cpu exch pool.
2686 	 *
2687 	 * This round up is required to align fc_cpu_mask
2688 	 * to exchange id's lower bits such that all incoming
2689 	 * frames of an exchange gets delivered to the same
2690 	 * cpu on which exchange originated by simple bitwise
2691 	 * AND operation between fc_cpu_mask and exchange id.
2692 	 */
2693 	fc_cpu_order = ilog2(roundup_pow_of_two(nr_cpu_ids));
2694 	fc_cpu_mask = (1 << fc_cpu_order) - 1;
2695 
2696 	fc_exch_workqueue = create_singlethread_workqueue("fc_exch_workqueue");
2697 	if (!fc_exch_workqueue)
2698 		goto err;
2699 	return 0;
2700 err:
2701 	kmem_cache_destroy(fc_em_cachep);
2702 	return -ENOMEM;
2703 }
2704 
2705 /**
2706  * fc_destroy_exch_mgr() - Destroy an exchange manager
2707  */
fc_destroy_exch_mgr(void)2708 void fc_destroy_exch_mgr(void)
2709 {
2710 	destroy_workqueue(fc_exch_workqueue);
2711 	kmem_cache_destroy(fc_em_cachep);
2712 }
2713