1/*
   2 * Copyright(c) 2007 Intel Corporation. All rights reserved.
   3 * Copyright(c) 2008 Red Hat, Inc.  All rights reserved.
   4 * Copyright(c) 2008 Mike Christie
   5 *
   6 * This program is free software; you can redistribute it and/or modify it
   7 * under the terms and conditions of the GNU General Public License,
   8 * version 2, as published by the Free Software Foundation.
   9 *
  10 * This program is distributed in the hope it will be useful, but WITHOUT
  11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13 * more details.
  14 *
  15 * You should have received a copy of the GNU General Public License along with
  16 * this program; if not, write to the Free Software Foundation, Inc.,
  17 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  18 *
  19 * Maintained at www.Open-FCoE.org
  20 */
  21
  22/*
  23 * Fibre Channel exchange and sequence handling.
  24 */
  25
  26#include <linux/timer.h>
  27#include <linux/slab.h>
  28#include <linux/err.h>
 
  29
  30#include <scsi/fc/fc_fc2.h>
  31
  32#include <scsi/libfc.h>
  33#include <scsi/fc_encode.h>
  34
  35#include "fc_libfc.h"
  36
  37u16	fc_cpu_mask;		/* cpu mask for possible cpus */
  38EXPORT_SYMBOL(fc_cpu_mask);
  39static u16	fc_cpu_order;	/* 2's power to represent total possible cpus */
  40static struct kmem_cache *fc_em_cachep;	       /* cache for exchanges */
  41static struct workqueue_struct *fc_exch_workqueue;
  42
  43/*
  44 * Structure and function definitions for managing Fibre Channel Exchanges
  45 * and Sequences.
  46 *
  47 * The three primary structures used here are fc_exch_mgr, fc_exch, and fc_seq.
  48 *
  49 * fc_exch_mgr holds the exchange state for an N port
  50 *
  51 * fc_exch holds state for one exchange and links to its active sequence.
  52 *
  53 * fc_seq holds the state for an individual sequence.
  54 */
  55
  56/**
  57 * struct fc_exch_pool - Per cpu exchange pool
  58 * @next_index:	  Next possible free exchange index
  59 * @total_exches: Total allocated exchanges
  60 * @lock:	  Exch pool lock
  61 * @ex_list:	  List of exchanges
  62 *
  63 * This structure manages per cpu exchanges in array of exchange pointers.
  64 * This array is allocated followed by struct fc_exch_pool memory for
  65 * assigned range of exchanges to per cpu pool.
  66 */
  67struct fc_exch_pool {
 
 
  68	u16		 next_index;
  69	u16		 total_exches;
  70
  71	/* two cache of free slot in exch array */
  72	u16		 left;
  73	u16		 right;
  74
  75	spinlock_t	 lock;
  76	struct list_head ex_list;
  77};
  78
  79/**
  80 * struct fc_exch_mgr - The Exchange Manager (EM).
  81 * @class:	    Default class for new sequences
  82 * @kref:	    Reference counter
  83 * @min_xid:	    Minimum exchange ID
  84 * @max_xid:	    Maximum exchange ID
  85 * @ep_pool:	    Reserved exchange pointers
  86 * @pool_max_index: Max exch array index in exch pool
  87 * @pool:	    Per cpu exch pool
  88 * @stats:	    Statistics structure
  89 *
  90 * This structure is the center for creating exchanges and sequences.
  91 * It manages the allocation of exchange IDs.
  92 */
  93struct fc_exch_mgr {
 
 
  94	enum fc_class	class;
  95	struct kref	kref;
  96	u16		min_xid;
  97	u16		max_xid;
  98	mempool_t	*ep_pool;
  99	u16		pool_max_index;
 100	struct fc_exch_pool *pool;
 101
 102	/*
 103	 * currently exchange mgr stats are updated but not used.
 104	 * either stats can be expose via sysfs or remove them
 105	 * all together if not used XXX
 106	 */
 107	struct {
 108		atomic_t no_free_exch;
 109		atomic_t no_free_exch_xid;
 110		atomic_t xid_not_found;
 111		atomic_t xid_busy;
 112		atomic_t seq_not_found;
 113		atomic_t non_bls_resp;
 114	} stats;
 115};
 116
 117/**
 118 * struct fc_exch_mgr_anchor - primary structure for list of EMs
 119 * @ema_list: Exchange Manager Anchor list
 120 * @mp:	      Exchange Manager associated with this anchor
 121 * @match:    Routine to determine if this anchor's EM should be used
 122 *
 123 * When walking the list of anchors the match routine will be called
 124 * for each anchor to determine if that EM should be used. The last
 125 * anchor in the list will always match to handle any exchanges not
 126 * handled by other EMs. The non-default EMs would be added to the
 127 * anchor list by HW that provides FCoE offloads.
 128 */
 129struct fc_exch_mgr_anchor {
 130	struct list_head ema_list;
 131	struct fc_exch_mgr *mp;
 132	bool (*match)(struct fc_frame *);
 133};
 134
 135static void fc_exch_rrq(struct fc_exch *);
 136static void fc_seq_ls_acc(struct fc_frame *);
 137static void fc_seq_ls_rjt(struct fc_frame *, enum fc_els_rjt_reason,
 138			  enum fc_els_rjt_explan);
 139static void fc_exch_els_rec(struct fc_frame *);
 140static void fc_exch_els_rrq(struct fc_frame *);
 141
 142/*
 143 * Internal implementation notes.
 144 *
 145 * The exchange manager is one by default in libfc but LLD may choose
 146 * to have one per CPU. The sequence manager is one per exchange manager
 147 * and currently never separated.
 148 *
 149 * Section 9.8 in FC-FS-2 specifies:  "The SEQ_ID is a one-byte field
 150 * assigned by the Sequence Initiator that shall be unique for a specific
 151 * D_ID and S_ID pair while the Sequence is open."   Note that it isn't
 152 * qualified by exchange ID, which one might think it would be.
 153 * In practice this limits the number of open sequences and exchanges to 256
 154 * per session.	 For most targets we could treat this limit as per exchange.
 155 *
 156 * The exchange and its sequence are freed when the last sequence is received.
 157 * It's possible for the remote port to leave an exchange open without
 158 * sending any sequences.
 159 *
 160 * Notes on reference counts:
 161 *
 162 * Exchanges are reference counted and exchange gets freed when the reference
 163 * count becomes zero.
 164 *
 165 * Timeouts:
 166 * Sequences are timed out for E_D_TOV and R_A_TOV.
 167 *
 168 * Sequence event handling:
 169 *
 170 * The following events may occur on initiator sequences:
 171 *
 172 *	Send.
 173 *	    For now, the whole thing is sent.
 174 *	Receive ACK
 175 *	    This applies only to class F.
 176 *	    The sequence is marked complete.
 177 *	ULP completion.
 178 *	    The upper layer calls fc_exch_done() when done
 179 *	    with exchange and sequence tuple.
 180 *	RX-inferred completion.
 181 *	    When we receive the next sequence on the same exchange, we can
 182 *	    retire the previous sequence ID.  (XXX not implemented).
 183 *	Timeout.
 184 *	    R_A_TOV frees the sequence ID.  If we're waiting for ACK,
 185 *	    E_D_TOV causes abort and calls upper layer response handler
 186 *	    with FC_EX_TIMEOUT error.
 187 *	Receive RJT
 188 *	    XXX defer.
 189 *	Send ABTS
 190 *	    On timeout.
 191 *
 192 * The following events may occur on recipient sequences:
 193 *
 194 *	Receive
 195 *	    Allocate sequence for first frame received.
 196 *	    Hold during receive handler.
 197 *	    Release when final frame received.
 198 *	    Keep status of last N of these for the ELS RES command.  XXX TBD.
 199 *	Receive ABTS
 200 *	    Deallocate sequence
 201 *	Send RJT
 202 *	    Deallocate
 203 *
 204 * For now, we neglect conditions where only part of a sequence was
 205 * received or transmitted, or where out-of-order receipt is detected.
 206 */
 207
 208/*
 209 * Locking notes:
 210 *
 211 * The EM code run in a per-CPU worker thread.
 212 *
 213 * To protect against concurrency between a worker thread code and timers,
 214 * sequence allocation and deallocation must be locked.
 215 *  - exchange refcnt can be done atomicly without locks.
 216 *  - sequence allocation must be locked by exch lock.
 217 *  - If the EM pool lock and ex_lock must be taken at the same time, then the
 218 *    EM pool lock must be taken before the ex_lock.
 219 */
 220
 221/*
 222 * opcode names for debugging.
 223 */
 224static char *fc_exch_rctl_names[] = FC_RCTL_NAMES_INIT;
 225
 226/**
 227 * fc_exch_name_lookup() - Lookup name by opcode
 228 * @op:	       Opcode to be looked up
 229 * @table:     Opcode/name table
 230 * @max_index: Index not to be exceeded
 231 *
 232 * This routine is used to determine a human-readable string identifying
 233 * a R_CTL opcode.
 234 */
 235static inline const char *fc_exch_name_lookup(unsigned int op, char **table,
 236					      unsigned int max_index)
 237{
 238	const char *name = NULL;
 239
 240	if (op < max_index)
 241		name = table[op];
 242	if (!name)
 243		name = "unknown";
 244	return name;
 245}
 246
 247/**
 248 * fc_exch_rctl_name() - Wrapper routine for fc_exch_name_lookup()
 249 * @op: The opcode to be looked up
 250 */
 251static const char *fc_exch_rctl_name(unsigned int op)
 252{
 253	return fc_exch_name_lookup(op, fc_exch_rctl_names,
 254				   ARRAY_SIZE(fc_exch_rctl_names));
 255}
 256
 257/**
 258 * fc_exch_hold() - Increment an exchange's reference count
 259 * @ep: Echange to be held
 260 */
 261static inline void fc_exch_hold(struct fc_exch *ep)
 262{
 263	atomic_inc(&ep->ex_refcnt);
 264}
 265
 266/**
 267 * fc_exch_setup_hdr() - Initialize a FC header by initializing some fields
 268 *			 and determine SOF and EOF.
 269 * @ep:	   The exchange to that will use the header
 270 * @fp:	   The frame whose header is to be modified
 271 * @f_ctl: F_CTL bits that will be used for the frame header
 272 *
 273 * The fields initialized by this routine are: fh_ox_id, fh_rx_id,
 274 * fh_seq_id, fh_seq_cnt and the SOF and EOF.
 275 */
 276static void fc_exch_setup_hdr(struct fc_exch *ep, struct fc_frame *fp,
 277			      u32 f_ctl)
 278{
 279	struct fc_frame_header *fh = fc_frame_header_get(fp);
 280	u16 fill;
 281
 282	fr_sof(fp) = ep->class;
 283	if (ep->seq.cnt)
 284		fr_sof(fp) = fc_sof_normal(ep->class);
 285
 286	if (f_ctl & FC_FC_END_SEQ) {
 287		fr_eof(fp) = FC_EOF_T;
 288		if (fc_sof_needs_ack(ep->class))
 289			fr_eof(fp) = FC_EOF_N;
 290		/*
 291		 * From F_CTL.
 292		 * The number of fill bytes to make the length a 4-byte
 293		 * multiple is the low order 2-bits of the f_ctl.
 294		 * The fill itself will have been cleared by the frame
 295		 * allocation.
 296		 * After this, the length will be even, as expected by
 297		 * the transport.
 298		 */
 299		fill = fr_len(fp) & 3;
 300		if (fill) {
 301			fill = 4 - fill;
 302			/* TODO, this may be a problem with fragmented skb */
 303			skb_put(fp_skb(fp), fill);
 304			hton24(fh->fh_f_ctl, f_ctl | fill);
 305		}
 306	} else {
 307		WARN_ON(fr_len(fp) % 4 != 0);	/* no pad to non last frame */
 308		fr_eof(fp) = FC_EOF_N;
 309	}
 310
 311	/*
 312	 * Initialize remainig fh fields
 313	 * from fc_fill_fc_hdr
 314	 */
 315	fh->fh_ox_id = htons(ep->oxid);
 316	fh->fh_rx_id = htons(ep->rxid);
 317	fh->fh_seq_id = ep->seq.id;
 318	fh->fh_seq_cnt = htons(ep->seq.cnt);
 319}
 320
 321/**
 322 * fc_exch_release() - Decrement an exchange's reference count
 323 * @ep: Exchange to be released
 324 *
 325 * If the reference count reaches zero and the exchange is complete,
 326 * it is freed.
 327 */
 328static void fc_exch_release(struct fc_exch *ep)
 329{
 330	struct fc_exch_mgr *mp;
 331
 332	if (atomic_dec_and_test(&ep->ex_refcnt)) {
 333		mp = ep->em;
 334		if (ep->destructor)
 335			ep->destructor(&ep->seq, ep->arg);
 336		WARN_ON(!(ep->esb_stat & ESB_ST_COMPLETE));
 337		mempool_free(ep, mp->ep_pool);
 338	}
 339}
 340
 341/**
 342 * fc_exch_done_locked() - Complete an exchange with the exchange lock held
 343 * @ep: The exchange that is complete
 344 */
 345static int fc_exch_done_locked(struct fc_exch *ep)
 346{
 347	int rc = 1;
 348
 349	/*
 350	 * We must check for completion in case there are two threads
 351	 * tyring to complete this. But the rrq code will reuse the
 352	 * ep, and in that case we only clear the resp and set it as
 353	 * complete, so it can be reused by the timer to send the rrq.
 354	 */
 355	ep->resp = NULL;
 356	if (ep->state & FC_EX_DONE)
 357		return rc;
 358	ep->esb_stat |= ESB_ST_COMPLETE;
 359
 360	if (!(ep->esb_stat & ESB_ST_REC_QUAL)) {
 361		ep->state |= FC_EX_DONE;
 362		if (cancel_delayed_work(&ep->timeout_work))
 363			atomic_dec(&ep->ex_refcnt); /* drop hold for timer */
 364		rc = 0;
 365	}
 366	return rc;
 367}
 368
 369/**
 370 * fc_exch_ptr_get() - Return an exchange from an exchange pool
 371 * @pool:  Exchange Pool to get an exchange from
 372 * @index: Index of the exchange within the pool
 373 *
 374 * Use the index to get an exchange from within an exchange pool. exches
 375 * will point to an array of exchange pointers. The index will select
 376 * the exchange within the array.
 377 */
 378static inline struct fc_exch *fc_exch_ptr_get(struct fc_exch_pool *pool,
 379					      u16 index)
 380{
 381	struct fc_exch **exches = (struct fc_exch **)(pool + 1);
 382	return exches[index];
 383}
 384
 385/**
 386 * fc_exch_ptr_set() - Assign an exchange to a slot in an exchange pool
 387 * @pool:  The pool to assign the exchange to
 388 * @index: The index in the pool where the exchange will be assigned
 389 * @ep:	   The exchange to assign to the pool
 390 */
 391static inline void fc_exch_ptr_set(struct fc_exch_pool *pool, u16 index,
 392				   struct fc_exch *ep)
 393{
 394	((struct fc_exch **)(pool + 1))[index] = ep;
 395}
 396
 397/**
 398 * fc_exch_delete() - Delete an exchange
 399 * @ep: The exchange to be deleted
 400 */
 401static void fc_exch_delete(struct fc_exch *ep)
 402{
 403	struct fc_exch_pool *pool;
 404	u16 index;
 405
 406	pool = ep->pool;
 407	spin_lock_bh(&pool->lock);
 408	WARN_ON(pool->total_exches <= 0);
 409	pool->total_exches--;
 410
 411	/* update cache of free slot */
 412	index = (ep->xid - ep->em->min_xid) >> fc_cpu_order;
 413	if (pool->left == FC_XID_UNKNOWN)
 414		pool->left = index;
 415	else if (pool->right == FC_XID_UNKNOWN)
 416		pool->right = index;
 417	else
 418		pool->next_index = index;
 419
 420	fc_exch_ptr_set(pool, index, NULL);
 421	list_del(&ep->ex_list);
 422	spin_unlock_bh(&pool->lock);
 423	fc_exch_release(ep);	/* drop hold for exch in mp */
 424}
 425
 426/**
 427 * fc_exch_timer_set_locked() - Start a timer for an exchange w/ the
 428 *				the exchange lock held
 429 * @ep:		The exchange whose timer will start
 430 * @timer_msec: The timeout period
 431 *
 432 * Used for upper level protocols to time out the exchange.
 433 * The timer is cancelled when it fires or when the exchange completes.
 434 */
 435static inline void fc_exch_timer_set_locked(struct fc_exch *ep,
 436					    unsigned int timer_msec)
 437{
 438	if (ep->state & (FC_EX_RST_CLEANUP | FC_EX_DONE))
 439		return;
 440
 441	FC_EXCH_DBG(ep, "Exchange timer armed\n");
 442
 443	if (queue_delayed_work(fc_exch_workqueue, &ep->timeout_work,
 444			       msecs_to_jiffies(timer_msec)))
 445		fc_exch_hold(ep);		/* hold for timer */
 446}
 447
 448/**
 449 * fc_exch_timer_set() - Lock the exchange and set the timer
 450 * @ep:		The exchange whose timer will start
 451 * @timer_msec: The timeout period
 452 */
 453static void fc_exch_timer_set(struct fc_exch *ep, unsigned int timer_msec)
 454{
 455	spin_lock_bh(&ep->ex_lock);
 456	fc_exch_timer_set_locked(ep, timer_msec);
 457	spin_unlock_bh(&ep->ex_lock);
 458}
 459
 460/**
 461 * fc_seq_send() - Send a frame using existing sequence/exchange pair
 462 * @lport: The local port that the exchange will be sent on
 463 * @sp:	   The sequence to be sent
 464 * @fp:	   The frame to be sent on the exchange
 465 */
 466static int fc_seq_send(struct fc_lport *lport, struct fc_seq *sp,
 467		       struct fc_frame *fp)
 468{
 469	struct fc_exch *ep;
 470	struct fc_frame_header *fh = fc_frame_header_get(fp);
 471	int error;
 472	u32 f_ctl;
 
 473
 474	ep = fc_seq_exch(sp);
 475	WARN_ON((ep->esb_stat & ESB_ST_SEQ_INIT) != ESB_ST_SEQ_INIT);
 476
 477	f_ctl = ntoh24(fh->fh_f_ctl);
 478	fc_exch_setup_hdr(ep, fp, f_ctl);
 479	fr_encaps(fp) = ep->encaps;
 480
 481	/*
 482	 * update sequence count if this frame is carrying
 483	 * multiple FC frames when sequence offload is enabled
 484	 * by LLD.
 485	 */
 486	if (fr_max_payload(fp))
 487		sp->cnt += DIV_ROUND_UP((fr_len(fp) - sizeof(*fh)),
 488					fr_max_payload(fp));
 489	else
 490		sp->cnt++;
 491
 492	/*
 493	 * Send the frame.
 494	 */
 495	error = lport->tt.frame_send(lport, fp);
 496
 497	if (fh->fh_type == FC_TYPE_BLS)
 498		return error;
 499
 500	/*
 501	 * Update the exchange and sequence flags,
 502	 * assuming all frames for the sequence have been sent.
 503	 * We can only be called to send once for each sequence.
 504	 */
 505	spin_lock_bh(&ep->ex_lock);
 506	ep->f_ctl = f_ctl & ~FC_FC_FIRST_SEQ;	/* not first seq */
 507	if (f_ctl & FC_FC_SEQ_INIT)
 508		ep->esb_stat &= ~ESB_ST_SEQ_INIT;
 509	spin_unlock_bh(&ep->ex_lock);
 510	return error;
 511}
 512
 513/**
 514 * fc_seq_alloc() - Allocate a sequence for a given exchange
 515 * @ep:	    The exchange to allocate a new sequence for
 516 * @seq_id: The sequence ID to be used
 517 *
 518 * We don't support multiple originated sequences on the same exchange.
 519 * By implication, any previously originated sequence on this exchange
 520 * is complete, and we reallocate the same sequence.
 521 */
 522static struct fc_seq *fc_seq_alloc(struct fc_exch *ep, u8 seq_id)
 523{
 524	struct fc_seq *sp;
 525
 526	sp = &ep->seq;
 527	sp->ssb_stat = 0;
 528	sp->cnt = 0;
 529	sp->id = seq_id;
 530	return sp;
 531}
 532
 533/**
 534 * fc_seq_start_next_locked() - Allocate a new sequence on the same
 535 *				exchange as the supplied sequence
 536 * @sp: The sequence/exchange to get a new sequence for
 537 */
 538static struct fc_seq *fc_seq_start_next_locked(struct fc_seq *sp)
 539{
 540	struct fc_exch *ep = fc_seq_exch(sp);
 541
 542	sp = fc_seq_alloc(ep, ep->seq_id++);
 543	FC_EXCH_DBG(ep, "f_ctl %6x seq %2x\n",
 544		    ep->f_ctl, sp->id);
 545	return sp;
 546}
 547
 548/**
 549 * fc_seq_start_next() - Lock the exchange and get a new sequence
 550 *			 for a given sequence/exchange pair
 551 * @sp: The sequence/exchange to get a new exchange for
 552 */
 553static struct fc_seq *fc_seq_start_next(struct fc_seq *sp)
 554{
 555	struct fc_exch *ep = fc_seq_exch(sp);
 556
 557	spin_lock_bh(&ep->ex_lock);
 558	sp = fc_seq_start_next_locked(sp);
 559	spin_unlock_bh(&ep->ex_lock);
 560
 561	return sp;
 562}
 563
 564/*
 565 * Set the response handler for the exchange associated with a sequence.
 566 */
 567static void fc_seq_set_resp(struct fc_seq *sp,
 568			    void (*resp)(struct fc_seq *, struct fc_frame *,
 569					 void *),
 570			    void *arg)
 571{
 572	struct fc_exch *ep = fc_seq_exch(sp);
 573
 574	spin_lock_bh(&ep->ex_lock);
 575	ep->resp = resp;
 576	ep->arg = arg;
 577	spin_unlock_bh(&ep->ex_lock);
 578}
 579
 580/**
 581 * fc_exch_abort_locked() - Abort an exchange
 582 * @ep:	The exchange to be aborted
 583 * @timer_msec: The period of time to wait before aborting
 584 *
 585 * Locking notes:  Called with exch lock held
 586 *
 587 * Return value: 0 on success else error code
 588 */
 589static int fc_exch_abort_locked(struct fc_exch *ep,
 590				unsigned int timer_msec)
 591{
 592	struct fc_seq *sp;
 593	struct fc_frame *fp;
 594	int error;
 595
 596	if (ep->esb_stat & (ESB_ST_COMPLETE | ESB_ST_ABNORMAL) ||
 597	    ep->state & (FC_EX_DONE | FC_EX_RST_CLEANUP))
 598		return -ENXIO;
 599
 600	/*
 601	 * Send the abort on a new sequence if possible.
 602	 */
 603	sp = fc_seq_start_next_locked(&ep->seq);
 604	if (!sp)
 605		return -ENOMEM;
 606
 607	ep->esb_stat |= ESB_ST_SEQ_INIT | ESB_ST_ABNORMAL;
 608	if (timer_msec)
 609		fc_exch_timer_set_locked(ep, timer_msec);
 610
 611	/*
 612	 * If not logged into the fabric, don't send ABTS but leave
 613	 * sequence active until next timeout.
 614	 */
 615	if (!ep->sid)
 616		return 0;
 617
 618	/*
 619	 * Send an abort for the sequence that timed out.
 620	 */
 621	fp = fc_frame_alloc(ep->lp, 0);
 622	if (fp) {
 623		fc_fill_fc_hdr(fp, FC_RCTL_BA_ABTS, ep->did, ep->sid,
 624			       FC_TYPE_BLS, FC_FC_END_SEQ | FC_FC_SEQ_INIT, 0);
 625		error = fc_seq_send(ep->lp, sp, fp);
 626	} else
 627		error = -ENOBUFS;
 628	return error;
 629}
 630
 631/**
 632 * fc_seq_exch_abort() - Abort an exchange and sequence
 633 * @req_sp:	The sequence to be aborted
 634 * @timer_msec: The period of time to wait before aborting
 635 *
 636 * Generally called because of a timeout or an abort from the upper layer.
 637 *
 638 * Return value: 0 on success else error code
 639 */
 640static int fc_seq_exch_abort(const struct fc_seq *req_sp,
 641			     unsigned int timer_msec)
 642{
 643	struct fc_exch *ep;
 644	int error;
 645
 646	ep = fc_seq_exch(req_sp);
 647	spin_lock_bh(&ep->ex_lock);
 648	error = fc_exch_abort_locked(ep, timer_msec);
 649	spin_unlock_bh(&ep->ex_lock);
 650	return error;
 651}
 652
 653/**
 654 * fc_exch_timeout() - Handle exchange timer expiration
 655 * @work: The work_struct identifying the exchange that timed out
 656 */
 657static void fc_exch_timeout(struct work_struct *work)
 658{
 659	struct fc_exch *ep = container_of(work, struct fc_exch,
 660					  timeout_work.work);
 661	struct fc_seq *sp = &ep->seq;
 662	void (*resp)(struct fc_seq *, struct fc_frame *fp, void *arg);
 663	void *arg;
 664	u32 e_stat;
 665	int rc = 1;
 666
 667	FC_EXCH_DBG(ep, "Exchange timed out\n");
 668
 669	spin_lock_bh(&ep->ex_lock);
 670	if (ep->state & (FC_EX_RST_CLEANUP | FC_EX_DONE))
 671		goto unlock;
 672
 673	e_stat = ep->esb_stat;
 674	if (e_stat & ESB_ST_COMPLETE) {
 675		ep->esb_stat = e_stat & ~ESB_ST_REC_QUAL;
 676		spin_unlock_bh(&ep->ex_lock);
 677		if (e_stat & ESB_ST_REC_QUAL)
 678			fc_exch_rrq(ep);
 679		goto done;
 680	} else {
 681		resp = ep->resp;
 682		arg = ep->arg;
 683		ep->resp = NULL;
 684		if (e_stat & ESB_ST_ABNORMAL)
 685			rc = fc_exch_done_locked(ep);
 686		spin_unlock_bh(&ep->ex_lock);
 687		if (!rc)
 688			fc_exch_delete(ep);
 689		if (resp)
 690			resp(sp, ERR_PTR(-FC_EX_TIMEOUT), arg);
 691		fc_seq_exch_abort(sp, 2 * ep->r_a_tov);
 692		goto done;
 693	}
 694unlock:
 695	spin_unlock_bh(&ep->ex_lock);
 696done:
 697	/*
 698	 * This release matches the hold taken when the timer was set.
 699	 */
 700	fc_exch_release(ep);
 701}
 702
 703/**
 704 * fc_exch_em_alloc() - Allocate an exchange from a specified EM.
 705 * @lport: The local port that the exchange is for
 706 * @mp:	   The exchange manager that will allocate the exchange
 707 *
 708 * Returns pointer to allocated fc_exch with exch lock held.
 709 */
 710static struct fc_exch *fc_exch_em_alloc(struct fc_lport *lport,
 711					struct fc_exch_mgr *mp)
 712{
 713	struct fc_exch *ep;
 714	unsigned int cpu;
 715	u16 index;
 716	struct fc_exch_pool *pool;
 717
 718	/* allocate memory for exchange */
 719	ep = mempool_alloc(mp->ep_pool, GFP_ATOMIC);
 720	if (!ep) {
 721		atomic_inc(&mp->stats.no_free_exch);
 722		goto out;
 723	}
 724	memset(ep, 0, sizeof(*ep));
 725
 726	cpu = get_cpu();
 727	pool = per_cpu_ptr(mp->pool, cpu);
 728	spin_lock_bh(&pool->lock);
 729	put_cpu();
 730
 731	/* peek cache of free slot */
 732	if (pool->left != FC_XID_UNKNOWN) {
 733		index = pool->left;
 734		pool->left = FC_XID_UNKNOWN;
 735		goto hit;
 736	}
 737	if (pool->right != FC_XID_UNKNOWN) {
 738		index = pool->right;
 739		pool->right = FC_XID_UNKNOWN;
 740		goto hit;
 741	}
 742
 743	index = pool->next_index;
 744	/* allocate new exch from pool */
 745	while (fc_exch_ptr_get(pool, index)) {
 746		index = index == mp->pool_max_index ? 0 : index + 1;
 747		if (index == pool->next_index)
 748			goto err;
 749	}
 750	pool->next_index = index == mp->pool_max_index ? 0 : index + 1;
 751hit:
 752	fc_exch_hold(ep);	/* hold for exch in mp */
 753	spin_lock_init(&ep->ex_lock);
 754	/*
 755	 * Hold exch lock for caller to prevent fc_exch_reset()
 756	 * from releasing exch	while fc_exch_alloc() caller is
 757	 * still working on exch.
 758	 */
 759	spin_lock_bh(&ep->ex_lock);
 760
 761	fc_exch_ptr_set(pool, index, ep);
 762	list_add_tail(&ep->ex_list, &pool->ex_list);
 763	fc_seq_alloc(ep, ep->seq_id++);
 764	pool->total_exches++;
 765	spin_unlock_bh(&pool->lock);
 766
 767	/*
 768	 *  update exchange
 769	 */
 770	ep->oxid = ep->xid = (index << fc_cpu_order | cpu) + mp->min_xid;
 771	ep->em = mp;
 772	ep->pool = pool;
 773	ep->lp = lport;
 774	ep->f_ctl = FC_FC_FIRST_SEQ;	/* next seq is first seq */
 775	ep->rxid = FC_XID_UNKNOWN;
 776	ep->class = mp->class;
 777	INIT_DELAYED_WORK(&ep->timeout_work, fc_exch_timeout);
 778out:
 779	return ep;
 780err:
 781	spin_unlock_bh(&pool->lock);
 782	atomic_inc(&mp->stats.no_free_exch_xid);
 783	mempool_free(ep, mp->ep_pool);
 784	return NULL;
 785}
 786
 787/**
 788 * fc_exch_alloc() - Allocate an exchange from an EM on a
 789 *		     local port's list of EMs.
 790 * @lport: The local port that will own the exchange
 791 * @fp:	   The FC frame that the exchange will be for
 792 *
 793 * This function walks the list of exchange manager(EM)
 794 * anchors to select an EM for a new exchange allocation. The
 795 * EM is selected when a NULL match function pointer is encountered
 796 * or when a call to a match function returns true.
 797 */
 798static inline struct fc_exch *fc_exch_alloc(struct fc_lport *lport,
 799					    struct fc_frame *fp)
 800{
 801	struct fc_exch_mgr_anchor *ema;
 802
 803	list_for_each_entry(ema, &lport->ema_list, ema_list)
 804		if (!ema->match || ema->match(fp))
 805			return fc_exch_em_alloc(lport, ema->mp);
 806	return NULL;
 807}
 808
 809/**
 810 * fc_exch_find() - Lookup and hold an exchange
 811 * @mp:	 The exchange manager to lookup the exchange from
 812 * @xid: The XID of the exchange to look up
 813 */
 814static struct fc_exch *fc_exch_find(struct fc_exch_mgr *mp, u16 xid)
 815{
 816	struct fc_exch_pool *pool;
 817	struct fc_exch *ep = NULL;
 818
 819	if ((xid >= mp->min_xid) && (xid <= mp->max_xid)) {
 820		pool = per_cpu_ptr(mp->pool, xid & fc_cpu_mask);
 821		spin_lock_bh(&pool->lock);
 822		ep = fc_exch_ptr_get(pool, (xid - mp->min_xid) >> fc_cpu_order);
 823		if (ep && ep->xid == xid)
 824			fc_exch_hold(ep);
 825		spin_unlock_bh(&pool->lock);
 826	}
 827	return ep;
 828}
 829
 830
 831/**
 832 * fc_exch_done() - Indicate that an exchange/sequence tuple is complete and
 833 *		    the memory allocated for the related objects may be freed.
 834 * @sp: The sequence that has completed
 835 */
 836static void fc_exch_done(struct fc_seq *sp)
 837{
 838	struct fc_exch *ep = fc_seq_exch(sp);
 839	int rc;
 840
 841	spin_lock_bh(&ep->ex_lock);
 842	rc = fc_exch_done_locked(ep);
 843	spin_unlock_bh(&ep->ex_lock);
 844	if (!rc)
 845		fc_exch_delete(ep);
 846}
 847
 848/**
 849 * fc_exch_resp() - Allocate a new exchange for a response frame
 850 * @lport: The local port that the exchange was for
 851 * @mp:	   The exchange manager to allocate the exchange from
 852 * @fp:	   The response frame
 853 *
 854 * Sets the responder ID in the frame header.
 855 */
 856static struct fc_exch *fc_exch_resp(struct fc_lport *lport,
 857				    struct fc_exch_mgr *mp,
 858				    struct fc_frame *fp)
 859{
 860	struct fc_exch *ep;
 861	struct fc_frame_header *fh;
 862
 863	ep = fc_exch_alloc(lport, fp);
 864	if (ep) {
 865		ep->class = fc_frame_class(fp);
 866
 867		/*
 868		 * Set EX_CTX indicating we're responding on this exchange.
 869		 */
 870		ep->f_ctl |= FC_FC_EX_CTX;	/* we're responding */
 871		ep->f_ctl &= ~FC_FC_FIRST_SEQ;	/* not new */
 872		fh = fc_frame_header_get(fp);
 873		ep->sid = ntoh24(fh->fh_d_id);
 874		ep->did = ntoh24(fh->fh_s_id);
 875		ep->oid = ep->did;
 876
 877		/*
 878		 * Allocated exchange has placed the XID in the
 879		 * originator field. Move it to the responder field,
 880		 * and set the originator XID from the frame.
 881		 */
 882		ep->rxid = ep->xid;
 883		ep->oxid = ntohs(fh->fh_ox_id);
 884		ep->esb_stat |= ESB_ST_RESP | ESB_ST_SEQ_INIT;
 885		if ((ntoh24(fh->fh_f_ctl) & FC_FC_SEQ_INIT) == 0)
 886			ep->esb_stat &= ~ESB_ST_SEQ_INIT;
 887
 888		fc_exch_hold(ep);	/* hold for caller */
 889		spin_unlock_bh(&ep->ex_lock);	/* lock from fc_exch_alloc */
 890	}
 891	return ep;
 892}
 893
 894/**
 895 * fc_seq_lookup_recip() - Find a sequence where the other end
 896 *			   originated the sequence
 897 * @lport: The local port that the frame was sent to
 898 * @mp:	   The Exchange Manager to lookup the exchange from
 899 * @fp:	   The frame associated with the sequence we're looking for
 900 *
 901 * If fc_pf_rjt_reason is FC_RJT_NONE then this function will have a hold
 902 * on the ep that should be released by the caller.
 903 */
 904static enum fc_pf_rjt_reason fc_seq_lookup_recip(struct fc_lport *lport,
 905						 struct fc_exch_mgr *mp,
 906						 struct fc_frame *fp)
 907{
 908	struct fc_frame_header *fh = fc_frame_header_get(fp);
 909	struct fc_exch *ep = NULL;
 910	struct fc_seq *sp = NULL;
 911	enum fc_pf_rjt_reason reject = FC_RJT_NONE;
 912	u32 f_ctl;
 913	u16 xid;
 914
 915	f_ctl = ntoh24(fh->fh_f_ctl);
 916	WARN_ON((f_ctl & FC_FC_SEQ_CTX) != 0);
 917
 918	/*
 919	 * Lookup or create the exchange if we will be creating the sequence.
 920	 */
 921	if (f_ctl & FC_FC_EX_CTX) {
 922		xid = ntohs(fh->fh_ox_id);	/* we originated exch */
 923		ep = fc_exch_find(mp, xid);
 924		if (!ep) {
 925			atomic_inc(&mp->stats.xid_not_found);
 926			reject = FC_RJT_OX_ID;
 927			goto out;
 928		}
 929		if (ep->rxid == FC_XID_UNKNOWN)
 930			ep->rxid = ntohs(fh->fh_rx_id);
 931		else if (ep->rxid != ntohs(fh->fh_rx_id)) {
 932			reject = FC_RJT_OX_ID;
 933			goto rel;
 934		}
 935	} else {
 936		xid = ntohs(fh->fh_rx_id);	/* we are the responder */
 937
 938		/*
 939		 * Special case for MDS issuing an ELS TEST with a
 940		 * bad rxid of 0.
 941		 * XXX take this out once we do the proper reject.
 942		 */
 943		if (xid == 0 && fh->fh_r_ctl == FC_RCTL_ELS_REQ &&
 944		    fc_frame_payload_op(fp) == ELS_TEST) {
 945			fh->fh_rx_id = htons(FC_XID_UNKNOWN);
 946			xid = FC_XID_UNKNOWN;
 947		}
 948
 949		/*
 950		 * new sequence - find the exchange
 951		 */
 952		ep = fc_exch_find(mp, xid);
 953		if ((f_ctl & FC_FC_FIRST_SEQ) && fc_sof_is_init(fr_sof(fp))) {
 954			if (ep) {
 955				atomic_inc(&mp->stats.xid_busy);
 956				reject = FC_RJT_RX_ID;
 957				goto rel;
 958			}
 959			ep = fc_exch_resp(lport, mp, fp);
 960			if (!ep) {
 961				reject = FC_RJT_EXCH_EST;	/* XXX */
 962				goto out;
 963			}
 964			xid = ep->xid;	/* get our XID */
 965		} else if (!ep) {
 966			atomic_inc(&mp->stats.xid_not_found);
 967			reject = FC_RJT_RX_ID;	/* XID not found */
 968			goto out;
 969		}
 970	}
 971
 972	/*
 973	 * At this point, we have the exchange held.
 974	 * Find or create the sequence.
 975	 */
 976	if (fc_sof_is_init(fr_sof(fp))) {
 977		sp = &ep->seq;
 978		sp->ssb_stat |= SSB_ST_RESP;
 979		sp->id = fh->fh_seq_id;
 980	} else {
 981		sp = &ep->seq;
 982		if (sp->id != fh->fh_seq_id) {
 983			atomic_inc(&mp->stats.seq_not_found);
 984			if (f_ctl & FC_FC_END_SEQ) {
 985				/*
 986				 * Update sequence_id based on incoming last
 987				 * frame of sequence exchange. This is needed
 988				 * for FCoE target where DDP has been used
 989				 * on target where, stack is indicated only
 990				 * about last frame's (payload _header) header.
 991				 * Whereas "seq_id" which is part of
 992				 * frame_header is allocated by initiator
 993				 * which is totally different from "seq_id"
 994				 * allocated when XFER_RDY was sent by target.
 995				 * To avoid false -ve which results into not
 996				 * sending RSP, hence write request on other
 997				 * end never finishes.
 998				 */
 999				spin_lock_bh(&ep->ex_lock);
1000				sp->ssb_stat |= SSB_ST_RESP;
1001				sp->id = fh->fh_seq_id;
1002				spin_unlock_bh(&ep->ex_lock);
1003			} else {
1004				/* sequence/exch should exist */
1005				reject = FC_RJT_SEQ_ID;
1006				goto rel;
1007			}
1008		}
1009	}
1010	WARN_ON(ep != fc_seq_exch(sp));
1011
1012	if (f_ctl & FC_FC_SEQ_INIT)
1013		ep->esb_stat |= ESB_ST_SEQ_INIT;
1014
1015	fr_seq(fp) = sp;
1016out:
1017	return reject;
1018rel:
1019	fc_exch_done(&ep->seq);
1020	fc_exch_release(ep);	/* hold from fc_exch_find/fc_exch_resp */
1021	return reject;
1022}
1023
1024/**
1025 * fc_seq_lookup_orig() - Find a sequence where this end
1026 *			  originated the sequence
1027 * @mp:	   The Exchange Manager to lookup the exchange from
1028 * @fp:	   The frame associated with the sequence we're looking for
1029 *
1030 * Does not hold the sequence for the caller.
1031 */
1032static struct fc_seq *fc_seq_lookup_orig(struct fc_exch_mgr *mp,
1033					 struct fc_frame *fp)
1034{
1035	struct fc_frame_header *fh = fc_frame_header_get(fp);
1036	struct fc_exch *ep;
1037	struct fc_seq *sp = NULL;
1038	u32 f_ctl;
1039	u16 xid;
1040
1041	f_ctl = ntoh24(fh->fh_f_ctl);
1042	WARN_ON((f_ctl & FC_FC_SEQ_CTX) != FC_FC_SEQ_CTX);
1043	xid = ntohs((f_ctl & FC_FC_EX_CTX) ? fh->fh_ox_id : fh->fh_rx_id);
1044	ep = fc_exch_find(mp, xid);
1045	if (!ep)
1046		return NULL;
1047	if (ep->seq.id == fh->fh_seq_id) {
1048		/*
1049		 * Save the RX_ID if we didn't previously know it.
1050		 */
1051		sp = &ep->seq;
1052		if ((f_ctl & FC_FC_EX_CTX) != 0 &&
1053		    ep->rxid == FC_XID_UNKNOWN) {
1054			ep->rxid = ntohs(fh->fh_rx_id);
1055		}
1056	}
1057	fc_exch_release(ep);
1058	return sp;
1059}
1060
1061/**
1062 * fc_exch_set_addr() - Set the source and destination IDs for an exchange
1063 * @ep:	     The exchange to set the addresses for
1064 * @orig_id: The originator's ID
1065 * @resp_id: The responder's ID
1066 *
1067 * Note this must be done before the first sequence of the exchange is sent.
1068 */
1069static void fc_exch_set_addr(struct fc_exch *ep,
1070			     u32 orig_id, u32 resp_id)
1071{
1072	ep->oid = orig_id;
1073	if (ep->esb_stat & ESB_ST_RESP) {
1074		ep->sid = resp_id;
1075		ep->did = orig_id;
1076	} else {
1077		ep->sid = orig_id;
1078		ep->did = resp_id;
1079	}
1080}
1081
1082/**
1083 * fc_seq_els_rsp_send() - Send an ELS response using information from
1084 *			   the existing sequence/exchange.
1085 * @fp:	      The received frame
1086 * @els_cmd:  The ELS command to be sent
1087 * @els_data: The ELS data to be sent
1088 *
1089 * The received frame is not freed.
1090 */
1091static void fc_seq_els_rsp_send(struct fc_frame *fp, enum fc_els_cmd els_cmd,
1092				struct fc_seq_els_data *els_data)
1093{
1094	switch (els_cmd) {
1095	case ELS_LS_RJT:
1096		fc_seq_ls_rjt(fp, els_data->reason, els_data->explan);
1097		break;
1098	case ELS_LS_ACC:
1099		fc_seq_ls_acc(fp);
1100		break;
1101	case ELS_RRQ:
1102		fc_exch_els_rrq(fp);
1103		break;
1104	case ELS_REC:
1105		fc_exch_els_rec(fp);
1106		break;
1107	default:
1108		FC_LPORT_DBG(fr_dev(fp), "Invalid ELS CMD:%x\n", els_cmd);
1109	}
1110}
1111
1112/**
1113 * fc_seq_send_last() - Send a sequence that is the last in the exchange
1114 * @sp:	     The sequence that is to be sent
1115 * @fp:	     The frame that will be sent on the sequence
1116 * @rctl:    The R_CTL information to be sent
1117 * @fh_type: The frame header type
1118 */
1119static void fc_seq_send_last(struct fc_seq *sp, struct fc_frame *fp,
1120			     enum fc_rctl rctl, enum fc_fh_type fh_type)
1121{
1122	u32 f_ctl;
1123	struct fc_exch *ep = fc_seq_exch(sp);
1124
1125	f_ctl = FC_FC_LAST_SEQ | FC_FC_END_SEQ | FC_FC_SEQ_INIT;
1126	f_ctl |= ep->f_ctl;
1127	fc_fill_fc_hdr(fp, rctl, ep->did, ep->sid, fh_type, f_ctl, 0);
1128	fc_seq_send(ep->lp, sp, fp);
1129}
1130
1131/**
1132 * fc_seq_send_ack() - Send an acknowledgement that we've received a frame
1133 * @sp:	   The sequence to send the ACK on
1134 * @rx_fp: The received frame that is being acknoledged
1135 *
1136 * Send ACK_1 (or equiv.) indicating we received something.
1137 */
1138static void fc_seq_send_ack(struct fc_seq *sp, const struct fc_frame *rx_fp)
1139{
1140	struct fc_frame *fp;
1141	struct fc_frame_header *rx_fh;
1142	struct fc_frame_header *fh;
1143	struct fc_exch *ep = fc_seq_exch(sp);
1144	struct fc_lport *lport = ep->lp;
1145	unsigned int f_ctl;
1146
1147	/*
1148	 * Don't send ACKs for class 3.
1149	 */
1150	if (fc_sof_needs_ack(fr_sof(rx_fp))) {
1151		fp = fc_frame_alloc(lport, 0);
1152		if (!fp)
1153			return;
1154
1155		fh = fc_frame_header_get(fp);
1156		fh->fh_r_ctl = FC_RCTL_ACK_1;
1157		fh->fh_type = FC_TYPE_BLS;
1158
1159		/*
1160		 * Form f_ctl by inverting EX_CTX and SEQ_CTX (bits 23, 22).
1161		 * Echo FIRST_SEQ, LAST_SEQ, END_SEQ, END_CONN, SEQ_INIT.
1162		 * Bits 9-8 are meaningful (retransmitted or unidirectional).
1163		 * Last ACK uses bits 7-6 (continue sequence),
1164		 * bits 5-4 are meaningful (what kind of ACK to use).
1165		 */
1166		rx_fh = fc_frame_header_get(rx_fp);
1167		f_ctl = ntoh24(rx_fh->fh_f_ctl);
1168		f_ctl &= FC_FC_EX_CTX | FC_FC_SEQ_CTX |
1169			FC_FC_FIRST_SEQ | FC_FC_LAST_SEQ |
1170			FC_FC_END_SEQ | FC_FC_END_CONN | FC_FC_SEQ_INIT |
1171			FC_FC_RETX_SEQ | FC_FC_UNI_TX;
1172		f_ctl ^= FC_FC_EX_CTX | FC_FC_SEQ_CTX;
1173		hton24(fh->fh_f_ctl, f_ctl);
1174
1175		fc_exch_setup_hdr(ep, fp, f_ctl);
1176		fh->fh_seq_id = rx_fh->fh_seq_id;
1177		fh->fh_seq_cnt = rx_fh->fh_seq_cnt;
1178		fh->fh_parm_offset = htonl(1);	/* ack single frame */
1179
1180		fr_sof(fp) = fr_sof(rx_fp);
1181		if (f_ctl & FC_FC_END_SEQ)
1182			fr_eof(fp) = FC_EOF_T;
1183		else
1184			fr_eof(fp) = FC_EOF_N;
1185
1186		lport->tt.frame_send(lport, fp);
1187	}
1188}
1189
1190/**
1191 * fc_exch_send_ba_rjt() - Send BLS Reject
1192 * @rx_fp:  The frame being rejected
1193 * @reason: The reason the frame is being rejected
1194 * @explan: The explanation for the rejection
1195 *
1196 * This is for rejecting BA_ABTS only.
1197 */
1198static void fc_exch_send_ba_rjt(struct fc_frame *rx_fp,
1199				enum fc_ba_rjt_reason reason,
1200				enum fc_ba_rjt_explan explan)
1201{
1202	struct fc_frame *fp;
1203	struct fc_frame_header *rx_fh;
1204	struct fc_frame_header *fh;
1205	struct fc_ba_rjt *rp;
1206	struct fc_lport *lport;
1207	unsigned int f_ctl;
1208
1209	lport = fr_dev(rx_fp);
1210	fp = fc_frame_alloc(lport, sizeof(*rp));
1211	if (!fp)
1212		return;
1213	fh = fc_frame_header_get(fp);
1214	rx_fh = fc_frame_header_get(rx_fp);
1215
1216	memset(fh, 0, sizeof(*fh) + sizeof(*rp));
1217
1218	rp = fc_frame_payload_get(fp, sizeof(*rp));
1219	rp->br_reason = reason;
1220	rp->br_explan = explan;
1221
1222	/*
1223	 * seq_id, cs_ctl, df_ctl and param/offset are zero.
1224	 */
1225	memcpy(fh->fh_s_id, rx_fh->fh_d_id, 3);
1226	memcpy(fh->fh_d_id, rx_fh->fh_s_id, 3);
1227	fh->fh_ox_id = rx_fh->fh_ox_id;
1228	fh->fh_rx_id = rx_fh->fh_rx_id;
1229	fh->fh_seq_cnt = rx_fh->fh_seq_cnt;
1230	fh->fh_r_ctl = FC_RCTL_BA_RJT;
1231	fh->fh_type = FC_TYPE_BLS;
1232
1233	/*
1234	 * Form f_ctl by inverting EX_CTX and SEQ_CTX (bits 23, 22).
1235	 * Echo FIRST_SEQ, LAST_SEQ, END_SEQ, END_CONN, SEQ_INIT.
1236	 * Bits 9-8 are meaningful (retransmitted or unidirectional).
1237	 * Last ACK uses bits 7-6 (continue sequence),
1238	 * bits 5-4 are meaningful (what kind of ACK to use).
1239	 * Always set LAST_SEQ, END_SEQ.
1240	 */
1241	f_ctl = ntoh24(rx_fh->fh_f_ctl);
1242	f_ctl &= FC_FC_EX_CTX | FC_FC_SEQ_CTX |
1243		FC_FC_END_CONN | FC_FC_SEQ_INIT |
1244		FC_FC_RETX_SEQ | FC_FC_UNI_TX;
1245	f_ctl ^= FC_FC_EX_CTX | FC_FC_SEQ_CTX;
1246	f_ctl |= FC_FC_LAST_SEQ | FC_FC_END_SEQ;
1247	f_ctl &= ~FC_FC_FIRST_SEQ;
1248	hton24(fh->fh_f_ctl, f_ctl);
1249
1250	fr_sof(fp) = fc_sof_class(fr_sof(rx_fp));
1251	fr_eof(fp) = FC_EOF_T;
1252	if (fc_sof_needs_ack(fr_sof(fp)))
1253		fr_eof(fp) = FC_EOF_N;
1254
1255	lport->tt.frame_send(lport, fp);
1256}
1257
1258/**
1259 * fc_exch_recv_abts() - Handle an incoming ABTS
1260 * @ep:	   The exchange the abort was on
1261 * @rx_fp: The ABTS frame
1262 *
1263 * This would be for target mode usually, but could be due to lost
1264 * FCP transfer ready, confirm or RRQ. We always handle this as an
1265 * exchange abort, ignoring the parameter.
1266 */
1267static void fc_exch_recv_abts(struct fc_exch *ep, struct fc_frame *rx_fp)
1268{
1269	struct fc_frame *fp;
1270	struct fc_ba_acc *ap;
1271	struct fc_frame_header *fh;
1272	struct fc_seq *sp;
1273
1274	if (!ep)
1275		goto reject;
1276	spin_lock_bh(&ep->ex_lock);
1277	if (ep->esb_stat & ESB_ST_COMPLETE) {
1278		spin_unlock_bh(&ep->ex_lock);
1279		goto reject;
1280	}
1281	if (!(ep->esb_stat & ESB_ST_REC_QUAL))
1282		fc_exch_hold(ep);		/* hold for REC_QUAL */
1283	ep->esb_stat |= ESB_ST_ABNORMAL | ESB_ST_REC_QUAL;
1284	fc_exch_timer_set_locked(ep, ep->r_a_tov);
1285
1286	fp = fc_frame_alloc(ep->lp, sizeof(*ap));
1287	if (!fp) {
1288		spin_unlock_bh(&ep->ex_lock);
1289		goto free;
1290	}
1291	fh = fc_frame_header_get(fp);
1292	ap = fc_frame_payload_get(fp, sizeof(*ap));
1293	memset(ap, 0, sizeof(*ap));
1294	sp = &ep->seq;
1295	ap->ba_high_seq_cnt = htons(0xffff);
1296	if (sp->ssb_stat & SSB_ST_RESP) {
1297		ap->ba_seq_id = sp->id;
1298		ap->ba_seq_id_val = FC_BA_SEQ_ID_VAL;
1299		ap->ba_high_seq_cnt = fh->fh_seq_cnt;
1300		ap->ba_low_seq_cnt = htons(sp->cnt);
1301	}
1302	sp = fc_seq_start_next_locked(sp);
1303	spin_unlock_bh(&ep->ex_lock);
1304	fc_seq_send_last(sp, fp, FC_RCTL_BA_ACC, FC_TYPE_BLS);
1305	fc_frame_free(rx_fp);
1306	return;
1307
1308reject:
1309	fc_exch_send_ba_rjt(rx_fp, FC_BA_RJT_UNABLE, FC_BA_RJT_INV_XID);
1310free:
1311	fc_frame_free(rx_fp);
1312}
1313
1314/**
1315 * fc_seq_assign() - Assign exchange and sequence for incoming request
1316 * @lport: The local port that received the request
1317 * @fp:    The request frame
1318 *
1319 * On success, the sequence pointer will be returned and also in fr_seq(@fp).
1320 * A reference will be held on the exchange/sequence for the caller, which
1321 * must call fc_seq_release().
1322 */
1323static struct fc_seq *fc_seq_assign(struct fc_lport *lport, struct fc_frame *fp)
1324{
1325	struct fc_exch_mgr_anchor *ema;
1326
1327	WARN_ON(lport != fr_dev(fp));
1328	WARN_ON(fr_seq(fp));
1329	fr_seq(fp) = NULL;
1330
1331	list_for_each_entry(ema, &lport->ema_list, ema_list)
1332		if ((!ema->match || ema->match(fp)) &&
1333		    fc_seq_lookup_recip(lport, ema->mp, fp) == FC_RJT_NONE)
1334			break;
1335	return fr_seq(fp);
1336}
1337
1338/**
1339 * fc_seq_release() - Release the hold
1340 * @sp:    The sequence.
1341 */
1342static void fc_seq_release(struct fc_seq *sp)
1343{
1344	fc_exch_release(fc_seq_exch(sp));
1345}
1346
1347/**
1348 * fc_exch_recv_req() - Handler for an incoming request
1349 * @lport: The local port that received the request
1350 * @mp:	   The EM that the exchange is on
1351 * @fp:	   The request frame
1352 *
1353 * This is used when the other end is originating the exchange
1354 * and the sequence.
1355 */
1356static void fc_exch_recv_req(struct fc_lport *lport, struct fc_exch_mgr *mp,
1357			     struct fc_frame *fp)
1358{
1359	struct fc_frame_header *fh = fc_frame_header_get(fp);
1360	struct fc_seq *sp = NULL;
1361	struct fc_exch *ep = NULL;
1362	enum fc_pf_rjt_reason reject;
1363
1364	/* We can have the wrong fc_lport at this point with NPIV, which is a
1365	 * problem now that we know a new exchange needs to be allocated
1366	 */
1367	lport = fc_vport_id_lookup(lport, ntoh24(fh->fh_d_id));
1368	if (!lport) {
1369		fc_frame_free(fp);
1370		return;
1371	}
1372	fr_dev(fp) = lport;
1373
1374	BUG_ON(fr_seq(fp));		/* XXX remove later */
1375
1376	/*
1377	 * If the RX_ID is 0xffff, don't allocate an exchange.
1378	 * The upper-level protocol may request one later, if needed.
1379	 */
1380	if (fh->fh_rx_id == htons(FC_XID_UNKNOWN))
1381		return lport->tt.lport_recv(lport, fp);
1382
1383	reject = fc_seq_lookup_recip(lport, mp, fp);
1384	if (reject == FC_RJT_NONE) {
1385		sp = fr_seq(fp);	/* sequence will be held */
1386		ep = fc_seq_exch(sp);
1387		fc_seq_send_ack(sp, fp);
1388		ep->encaps = fr_encaps(fp);
1389
1390		/*
1391		 * Call the receive function.
1392		 *
1393		 * The receive function may allocate a new sequence
1394		 * over the old one, so we shouldn't change the
1395		 * sequence after this.
1396		 *
1397		 * The frame will be freed by the receive function.
1398		 * If new exch resp handler is valid then call that
1399		 * first.
1400		 */
1401		if (ep->resp)
1402			ep->resp(sp, fp, ep->arg);
1403		else
1404			lport->tt.lport_recv(lport, fp);
1405		fc_exch_release(ep);	/* release from lookup */
1406	} else {
1407		FC_LPORT_DBG(lport, "exch/seq lookup failed: reject %x\n",
1408			     reject);
1409		fc_frame_free(fp);
1410	}
1411}
1412
1413/**
1414 * fc_exch_recv_seq_resp() - Handler for an incoming response where the other
1415 *			     end is the originator of the sequence that is a
1416 *			     response to our initial exchange
1417 * @mp: The EM that the exchange is on
1418 * @fp: The response frame
1419 */
1420static void fc_exch_recv_seq_resp(struct fc_exch_mgr *mp, struct fc_frame *fp)
1421{
1422	struct fc_frame_header *fh = fc_frame_header_get(fp);
1423	struct fc_seq *sp;
1424	struct fc_exch *ep;
1425	enum fc_sof sof;
1426	u32 f_ctl;
1427	void (*resp)(struct fc_seq *, struct fc_frame *fp, void *arg);
1428	void *ex_resp_arg;
1429	int rc;
1430
1431	ep = fc_exch_find(mp, ntohs(fh->fh_ox_id));
1432	if (!ep) {
1433		atomic_inc(&mp->stats.xid_not_found);
1434		goto out;
1435	}
1436	if (ep->esb_stat & ESB_ST_COMPLETE) {
1437		atomic_inc(&mp->stats.xid_not_found);
1438		goto rel;
1439	}
1440	if (ep->rxid == FC_XID_UNKNOWN)
1441		ep->rxid = ntohs(fh->fh_rx_id);
1442	if (ep->sid != 0 && ep->sid != ntoh24(fh->fh_d_id)) {
1443		atomic_inc(&mp->stats.xid_not_found);
1444		goto rel;
1445	}
1446	if (ep->did != ntoh24(fh->fh_s_id) &&
1447	    ep->did != FC_FID_FLOGI) {
1448		atomic_inc(&mp->stats.xid_not_found);
1449		goto rel;
1450	}
1451	sof = fr_sof(fp);
1452	sp = &ep->seq;
1453	if (fc_sof_is_init(sof)) {
1454		sp->ssb_stat |= SSB_ST_RESP;
1455		sp->id = fh->fh_seq_id;
1456	} else if (sp->id != fh->fh_seq_id) {
1457		atomic_inc(&mp->stats.seq_not_found);
1458		goto rel;
1459	}
1460
1461	f_ctl = ntoh24(fh->fh_f_ctl);
1462	fr_seq(fp) = sp;
1463	if (f_ctl & FC_FC_SEQ_INIT)
1464		ep->esb_stat |= ESB_ST_SEQ_INIT;
1465
1466	if (fc_sof_needs_ack(sof))
1467		fc_seq_send_ack(sp, fp);
1468	resp = ep->resp;
1469	ex_resp_arg = ep->arg;
1470
1471	if (fh->fh_type != FC_TYPE_FCP && fr_eof(fp) == FC_EOF_T &&
1472	    (f_ctl & (FC_FC_LAST_SEQ | FC_FC_END_SEQ)) ==
1473	    (FC_FC_LAST_SEQ | FC_FC_END_SEQ)) {
1474		spin_lock_bh(&ep->ex_lock);
1475		resp = ep->resp;
1476		rc = fc_exch_done_locked(ep);
1477		WARN_ON(fc_seq_exch(sp) != ep);
1478		spin_unlock_bh(&ep->ex_lock);
1479		if (!rc)
1480			fc_exch_delete(ep);
1481	}
1482
1483	/*
1484	 * Call the receive function.
1485	 * The sequence is held (has a refcnt) for us,
1486	 * but not for the receive function.
1487	 *
1488	 * The receive function may allocate a new sequence
1489	 * over the old one, so we shouldn't change the
1490	 * sequence after this.
1491	 *
1492	 * The frame will be freed by the receive function.
1493	 * If new exch resp handler is valid then call that
1494	 * first.
1495	 */
1496	if (resp)
1497		resp(sp, fp, ex_resp_arg);
1498	else
1499		fc_frame_free(fp);
1500	fc_exch_release(ep);
1501	return;
1502rel:
1503	fc_exch_release(ep);
1504out:
1505	fc_frame_free(fp);
1506}
1507
1508/**
1509 * fc_exch_recv_resp() - Handler for a sequence where other end is
1510 *			 responding to our sequence
1511 * @mp: The EM that the exchange is on
1512 * @fp: The response frame
1513 */
1514static void fc_exch_recv_resp(struct fc_exch_mgr *mp, struct fc_frame *fp)
1515{
1516	struct fc_seq *sp;
1517
1518	sp = fc_seq_lookup_orig(mp, fp);	/* doesn't hold sequence */
1519
1520	if (!sp)
1521		atomic_inc(&mp->stats.xid_not_found);
1522	else
1523		atomic_inc(&mp->stats.non_bls_resp);
1524
1525	fc_frame_free(fp);
1526}
1527
1528/**
1529 * fc_exch_abts_resp() - Handler for a response to an ABT
1530 * @ep: The exchange that the frame is on
1531 * @fp: The response frame
1532 *
1533 * This response would be to an ABTS cancelling an exchange or sequence.
1534 * The response can be either BA_ACC or BA_RJT
1535 */
1536static void fc_exch_abts_resp(struct fc_exch *ep, struct fc_frame *fp)
1537{
1538	void (*resp)(struct fc_seq *, struct fc_frame *fp, void *arg);
1539	void *ex_resp_arg;
1540	struct fc_frame_header *fh;
1541	struct fc_ba_acc *ap;
1542	struct fc_seq *sp;
1543	u16 low;
1544	u16 high;
1545	int rc = 1, has_rec = 0;
1546
1547	fh = fc_frame_header_get(fp);
1548	FC_EXCH_DBG(ep, "exch: BLS rctl %x - %s\n", fh->fh_r_ctl,
1549		    fc_exch_rctl_name(fh->fh_r_ctl));
1550
1551	if (cancel_delayed_work_sync(&ep->timeout_work))
1552		fc_exch_release(ep);	/* release from pending timer hold */
1553
1554	spin_lock_bh(&ep->ex_lock);
1555	switch (fh->fh_r_ctl) {
1556	case FC_RCTL_BA_ACC:
1557		ap = fc_frame_payload_get(fp, sizeof(*ap));
1558		if (!ap)
1559			break;
1560
1561		/*
1562		 * Decide whether to establish a Recovery Qualifier.
1563		 * We do this if there is a non-empty SEQ_CNT range and
1564		 * SEQ_ID is the same as the one we aborted.
1565		 */
1566		low = ntohs(ap->ba_low_seq_cnt);
1567		high = ntohs(ap->ba_high_seq_cnt);
1568		if ((ep->esb_stat & ESB_ST_REC_QUAL) == 0 &&
1569		    (ap->ba_seq_id_val != FC_BA_SEQ_ID_VAL ||
1570		     ap->ba_seq_id == ep->seq_id) && low != high) {
1571			ep->esb_stat |= ESB_ST_REC_QUAL;
1572			fc_exch_hold(ep);  /* hold for recovery qualifier */
1573			has_rec = 1;
1574		}
1575		break;
1576	case FC_RCTL_BA_RJT:
1577		break;
1578	default:
1579		break;
1580	}
1581
1582	resp = ep->resp;
1583	ex_resp_arg = ep->arg;
1584
1585	/* do we need to do some other checks here. Can we reuse more of
1586	 * fc_exch_recv_seq_resp
1587	 */
1588	sp = &ep->seq;
1589	/*
1590	 * do we want to check END_SEQ as well as LAST_SEQ here?
1591	 */
1592	if (ep->fh_type != FC_TYPE_FCP &&
1593	    ntoh24(fh->fh_f_ctl) & FC_FC_LAST_SEQ)
1594		rc = fc_exch_done_locked(ep);
1595	spin_unlock_bh(&ep->ex_lock);
1596	if (!rc)
1597		fc_exch_delete(ep);
1598
1599	if (resp)
1600		resp(sp, fp, ex_resp_arg);
1601	else
1602		fc_frame_free(fp);
1603
1604	if (has_rec)
1605		fc_exch_timer_set(ep, ep->r_a_tov);
1606
1607}
1608
1609/**
1610 * fc_exch_recv_bls() - Handler for a BLS sequence
1611 * @mp: The EM that the exchange is on
1612 * @fp: The request frame
1613 *
1614 * The BLS frame is always a sequence initiated by the remote side.
1615 * We may be either the originator or recipient of the exchange.
1616 */
1617static void fc_exch_recv_bls(struct fc_exch_mgr *mp, struct fc_frame *fp)
1618{
1619	struct fc_frame_header *fh;
1620	struct fc_exch *ep;
1621	u32 f_ctl;
1622
1623	fh = fc_frame_header_get(fp);
1624	f_ctl = ntoh24(fh->fh_f_ctl);
1625	fr_seq(fp) = NULL;
1626
1627	ep = fc_exch_find(mp, (f_ctl & FC_FC_EX_CTX) ?
1628			  ntohs(fh->fh_ox_id) : ntohs(fh->fh_rx_id));
1629	if (ep && (f_ctl & FC_FC_SEQ_INIT)) {
1630		spin_lock_bh(&ep->ex_lock);
1631		ep->esb_stat |= ESB_ST_SEQ_INIT;
1632		spin_unlock_bh(&ep->ex_lock);
1633	}
1634	if (f_ctl & FC_FC_SEQ_CTX) {
1635		/*
1636		 * A response to a sequence we initiated.
1637		 * This should only be ACKs for class 2 or F.
1638		 */
1639		switch (fh->fh_r_ctl) {
1640		case FC_RCTL_ACK_1:
1641		case FC_RCTL_ACK_0:
1642			break;
1643		default:
1644			FC_EXCH_DBG(ep, "BLS rctl %x - %s received",
1645				    fh->fh_r_ctl,
1646				    fc_exch_rctl_name(fh->fh_r_ctl));
 
1647			break;
1648		}
1649		fc_frame_free(fp);
1650	} else {
1651		switch (fh->fh_r_ctl) {
1652		case FC_RCTL_BA_RJT:
1653		case FC_RCTL_BA_ACC:
1654			if (ep)
1655				fc_exch_abts_resp(ep, fp);
1656			else
1657				fc_frame_free(fp);
1658			break;
1659		case FC_RCTL_BA_ABTS:
1660			fc_exch_recv_abts(ep, fp);
1661			break;
1662		default:			/* ignore junk */
1663			fc_frame_free(fp);
1664			break;
1665		}
1666	}
1667	if (ep)
1668		fc_exch_release(ep);	/* release hold taken by fc_exch_find */
1669}
1670
1671/**
1672 * fc_seq_ls_acc() - Accept sequence with LS_ACC
1673 * @rx_fp: The received frame, not freed here.
1674 *
1675 * If this fails due to allocation or transmit congestion, assume the
1676 * originator will repeat the sequence.
1677 */
1678static void fc_seq_ls_acc(struct fc_frame *rx_fp)
1679{
1680	struct fc_lport *lport;
1681	struct fc_els_ls_acc *acc;
1682	struct fc_frame *fp;
1683
1684	lport = fr_dev(rx_fp);
1685	fp = fc_frame_alloc(lport, sizeof(*acc));
1686	if (!fp)
1687		return;
1688	acc = fc_frame_payload_get(fp, sizeof(*acc));
1689	memset(acc, 0, sizeof(*acc));
1690	acc->la_cmd = ELS_LS_ACC;
1691	fc_fill_reply_hdr(fp, rx_fp, FC_RCTL_ELS_REP, 0);
1692	lport->tt.frame_send(lport, fp);
1693}
1694
1695/**
1696 * fc_seq_ls_rjt() - Reject a sequence with ELS LS_RJT
1697 * @rx_fp: The received frame, not freed here.
1698 * @reason: The reason the sequence is being rejected
1699 * @explan: The explanation for the rejection
1700 *
1701 * If this fails due to allocation or transmit congestion, assume the
1702 * originator will repeat the sequence.
1703 */
1704static void fc_seq_ls_rjt(struct fc_frame *rx_fp, enum fc_els_rjt_reason reason,
1705			  enum fc_els_rjt_explan explan)
1706{
1707	struct fc_lport *lport;
1708	struct fc_els_ls_rjt *rjt;
1709	struct fc_frame *fp;
1710
1711	lport = fr_dev(rx_fp);
1712	fp = fc_frame_alloc(lport, sizeof(*rjt));
1713	if (!fp)
1714		return;
1715	rjt = fc_frame_payload_get(fp, sizeof(*rjt));
1716	memset(rjt, 0, sizeof(*rjt));
1717	rjt->er_cmd = ELS_LS_RJT;
1718	rjt->er_reason = reason;
1719	rjt->er_explan = explan;
1720	fc_fill_reply_hdr(fp, rx_fp, FC_RCTL_ELS_REP, 0);
1721	lport->tt.frame_send(lport, fp);
1722}
1723
1724/**
1725 * fc_exch_reset() - Reset an exchange
1726 * @ep: The exchange to be reset
1727 */
1728static void fc_exch_reset(struct fc_exch *ep)
1729{
1730	struct fc_seq *sp;
1731	void (*resp)(struct fc_seq *, struct fc_frame *, void *);
1732	void *arg;
1733	int rc = 1;
1734
1735	spin_lock_bh(&ep->ex_lock);
1736	fc_exch_abort_locked(ep, 0);
1737	ep->state |= FC_EX_RST_CLEANUP;
1738	if (cancel_delayed_work(&ep->timeout_work))
1739		atomic_dec(&ep->ex_refcnt);	/* drop hold for timer */
1740	resp = ep->resp;
1741	ep->resp = NULL;
1742	if (ep->esb_stat & ESB_ST_REC_QUAL)
1743		atomic_dec(&ep->ex_refcnt);	/* drop hold for rec_qual */
1744	ep->esb_stat &= ~ESB_ST_REC_QUAL;
1745	arg = ep->arg;
1746	sp = &ep->seq;
1747	rc = fc_exch_done_locked(ep);
1748	spin_unlock_bh(&ep->ex_lock);
1749	if (!rc)
1750		fc_exch_delete(ep);
1751
1752	if (resp)
1753		resp(sp, ERR_PTR(-FC_EX_CLOSED), arg);
1754}
1755
1756/**
1757 * fc_exch_pool_reset() - Reset a per cpu exchange pool
1758 * @lport: The local port that the exchange pool is on
1759 * @pool:  The exchange pool to be reset
1760 * @sid:   The source ID
1761 * @did:   The destination ID
1762 *
1763 * Resets a per cpu exches pool, releasing all of its sequences
1764 * and exchanges. If sid is non-zero then reset only exchanges
1765 * we sourced from the local port's FID. If did is non-zero then
1766 * only reset exchanges destined for the local port's FID.
1767 */
1768static void fc_exch_pool_reset(struct fc_lport *lport,
1769			       struct fc_exch_pool *pool,
1770			       u32 sid, u32 did)
1771{
1772	struct fc_exch *ep;
1773	struct fc_exch *next;
1774
1775	spin_lock_bh(&pool->lock);
1776restart:
1777	list_for_each_entry_safe(ep, next, &pool->ex_list, ex_list) {
1778		if ((lport == ep->lp) &&
1779		    (sid == 0 || sid == ep->sid) &&
1780		    (did == 0 || did == ep->did)) {
1781			fc_exch_hold(ep);
1782			spin_unlock_bh(&pool->lock);
1783
1784			fc_exch_reset(ep);
1785
1786			fc_exch_release(ep);
1787			spin_lock_bh(&pool->lock);
1788
1789			/*
1790			 * must restart loop incase while lock
1791			 * was down multiple eps were released.
1792			 */
1793			goto restart;
1794		}
1795	}
 
 
 
1796	spin_unlock_bh(&pool->lock);
1797}
1798
1799/**
1800 * fc_exch_mgr_reset() - Reset all EMs of a local port
1801 * @lport: The local port whose EMs are to be reset
1802 * @sid:   The source ID
1803 * @did:   The destination ID
1804 *
1805 * Reset all EMs associated with a given local port. Release all
1806 * sequences and exchanges. If sid is non-zero then reset only the
1807 * exchanges sent from the local port's FID. If did is non-zero then
1808 * reset only exchanges destined for the local port's FID.
1809 */
1810void fc_exch_mgr_reset(struct fc_lport *lport, u32 sid, u32 did)
1811{
1812	struct fc_exch_mgr_anchor *ema;
1813	unsigned int cpu;
1814
1815	list_for_each_entry(ema, &lport->ema_list, ema_list) {
1816		for_each_possible_cpu(cpu)
1817			fc_exch_pool_reset(lport,
1818					   per_cpu_ptr(ema->mp->pool, cpu),
1819					   sid, did);
1820	}
1821}
1822EXPORT_SYMBOL(fc_exch_mgr_reset);
1823
1824/**
1825 * fc_exch_lookup() - find an exchange
1826 * @lport: The local port
1827 * @xid: The exchange ID
1828 *
1829 * Returns exchange pointer with hold for caller, or NULL if not found.
1830 */
1831static struct fc_exch *fc_exch_lookup(struct fc_lport *lport, u32 xid)
1832{
1833	struct fc_exch_mgr_anchor *ema;
1834
1835	list_for_each_entry(ema, &lport->ema_list, ema_list)
1836		if (ema->mp->min_xid <= xid && xid <= ema->mp->max_xid)
1837			return fc_exch_find(ema->mp, xid);
1838	return NULL;
1839}
1840
1841/**
1842 * fc_exch_els_rec() - Handler for ELS REC (Read Exchange Concise) requests
1843 * @rfp: The REC frame, not freed here.
1844 *
1845 * Note that the requesting port may be different than the S_ID in the request.
1846 */
1847static void fc_exch_els_rec(struct fc_frame *rfp)
1848{
1849	struct fc_lport *lport;
1850	struct fc_frame *fp;
1851	struct fc_exch *ep;
1852	struct fc_els_rec *rp;
1853	struct fc_els_rec_acc *acc;
1854	enum fc_els_rjt_reason reason = ELS_RJT_LOGIC;
1855	enum fc_els_rjt_explan explan;
1856	u32 sid;
1857	u16 rxid;
1858	u16 oxid;
1859
1860	lport = fr_dev(rfp);
1861	rp = fc_frame_payload_get(rfp, sizeof(*rp));
1862	explan = ELS_EXPL_INV_LEN;
1863	if (!rp)
1864		goto reject;
1865	sid = ntoh24(rp->rec_s_id);
1866	rxid = ntohs(rp->rec_rx_id);
1867	oxid = ntohs(rp->rec_ox_id);
1868
1869	ep = fc_exch_lookup(lport,
1870			    sid == fc_host_port_id(lport->host) ? oxid : rxid);
1871	explan = ELS_EXPL_OXID_RXID;
1872	if (!ep)
1873		goto reject;
1874	if (ep->oid != sid || oxid != ep->oxid)
1875		goto rel;
1876	if (rxid != FC_XID_UNKNOWN && rxid != ep->rxid)
1877		goto rel;
1878	fp = fc_frame_alloc(lport, sizeof(*acc));
1879	if (!fp)
1880		goto out;
1881
1882	acc = fc_frame_payload_get(fp, sizeof(*acc));
1883	memset(acc, 0, sizeof(*acc));
1884	acc->reca_cmd = ELS_LS_ACC;
1885	acc->reca_ox_id = rp->rec_ox_id;
1886	memcpy(acc->reca_ofid, rp->rec_s_id, 3);
1887	acc->reca_rx_id = htons(ep->rxid);
1888	if (ep->sid == ep->oid)
1889		hton24(acc->reca_rfid, ep->did);
1890	else
1891		hton24(acc->reca_rfid, ep->sid);
1892	acc->reca_fc4value = htonl(ep->seq.rec_data);
1893	acc->reca_e_stat = htonl(ep->esb_stat & (ESB_ST_RESP |
1894						 ESB_ST_SEQ_INIT |
1895						 ESB_ST_COMPLETE));
1896	fc_fill_reply_hdr(fp, rfp, FC_RCTL_ELS_REP, 0);
1897	lport->tt.frame_send(lport, fp);
1898out:
1899	fc_exch_release(ep);
1900	return;
1901
1902rel:
1903	fc_exch_release(ep);
1904reject:
1905	fc_seq_ls_rjt(rfp, reason, explan);
1906}
1907
1908/**
1909 * fc_exch_rrq_resp() - Handler for RRQ responses
1910 * @sp:	 The sequence that the RRQ is on
1911 * @fp:	 The RRQ frame
1912 * @arg: The exchange that the RRQ is on
1913 *
1914 * TODO: fix error handler.
1915 */
1916static void fc_exch_rrq_resp(struct fc_seq *sp, struct fc_frame *fp, void *arg)
1917{
1918	struct fc_exch *aborted_ep = arg;
1919	unsigned int op;
1920
1921	if (IS_ERR(fp)) {
1922		int err = PTR_ERR(fp);
1923
1924		if (err == -FC_EX_CLOSED || err == -FC_EX_TIMEOUT)
1925			goto cleanup;
1926		FC_EXCH_DBG(aborted_ep, "Cannot process RRQ, "
1927			    "frame error %d\n", err);
1928		return;
1929	}
1930
1931	op = fc_frame_payload_op(fp);
1932	fc_frame_free(fp);
1933
1934	switch (op) {
1935	case ELS_LS_RJT:
1936		FC_EXCH_DBG(aborted_ep, "LS_RJT for RRQ");
1937		/* fall through */
1938	case ELS_LS_ACC:
1939		goto cleanup;
1940	default:
1941		FC_EXCH_DBG(aborted_ep, "unexpected response op %x "
1942			    "for RRQ", op);
1943		return;
1944	}
1945
1946cleanup:
1947	fc_exch_done(&aborted_ep->seq);
1948	/* drop hold for rec qual */
1949	fc_exch_release(aborted_ep);
1950}
1951
1952
1953/**
1954 * fc_exch_seq_send() - Send a frame using a new exchange and sequence
1955 * @lport:	The local port to send the frame on
1956 * @fp:		The frame to be sent
1957 * @resp:	The response handler for this request
1958 * @destructor: The destructor for the exchange
1959 * @arg:	The argument to be passed to the response handler
1960 * @timer_msec: The timeout period for the exchange
1961 *
1962 * The frame pointer with some of the header's fields must be
1963 * filled before calling this routine, those fields are:
1964 *
1965 * - routing control
1966 * - FC port did
1967 * - FC port sid
1968 * - FC header type
1969 * - frame control
1970 * - parameter or relative offset
1971 */
1972static struct fc_seq *fc_exch_seq_send(struct fc_lport *lport,
1973				       struct fc_frame *fp,
1974				       void (*resp)(struct fc_seq *,
1975						    struct fc_frame *fp,
1976						    void *arg),
1977				       void (*destructor)(struct fc_seq *,
1978							  void *),
1979				       void *arg, u32 timer_msec)
1980{
1981	struct fc_exch *ep;
1982	struct fc_seq *sp = NULL;
1983	struct fc_frame_header *fh;
1984	struct fc_fcp_pkt *fsp = NULL;
1985	int rc = 1;
1986
1987	ep = fc_exch_alloc(lport, fp);
1988	if (!ep) {
1989		fc_frame_free(fp);
1990		return NULL;
1991	}
1992	ep->esb_stat |= ESB_ST_SEQ_INIT;
1993	fh = fc_frame_header_get(fp);
1994	fc_exch_set_addr(ep, ntoh24(fh->fh_s_id), ntoh24(fh->fh_d_id));
1995	ep->resp = resp;
1996	ep->destructor = destructor;
1997	ep->arg = arg;
1998	ep->r_a_tov = FC_DEF_R_A_TOV;
1999	ep->lp = lport;
2000	sp = &ep->seq;
2001
2002	ep->fh_type = fh->fh_type; /* save for possbile timeout handling */
2003	ep->f_ctl = ntoh24(fh->fh_f_ctl);
2004	fc_exch_setup_hdr(ep, fp, ep->f_ctl);
2005	sp->cnt++;
2006
2007	if (ep->xid <= lport->lro_xid && fh->fh_r_ctl == FC_RCTL_DD_UNSOL_CMD) {
2008		fsp = fr_fsp(fp);
2009		fc_fcp_ddp_setup(fr_fsp(fp), ep->xid);
2010	}
2011
2012	if (unlikely(lport->tt.frame_send(lport, fp)))
2013		goto err;
2014
2015	if (timer_msec)
2016		fc_exch_timer_set_locked(ep, timer_msec);
2017	ep->f_ctl &= ~FC_FC_FIRST_SEQ;	/* not first seq */
2018
2019	if (ep->f_ctl & FC_FC_SEQ_INIT)
2020		ep->esb_stat &= ~ESB_ST_SEQ_INIT;
2021	spin_unlock_bh(&ep->ex_lock);
2022	return sp;
2023err:
2024	if (fsp)
2025		fc_fcp_ddp_done(fsp);
2026	rc = fc_exch_done_locked(ep);
2027	spin_unlock_bh(&ep->ex_lock);
2028	if (!rc)
2029		fc_exch_delete(ep);
2030	return NULL;
2031}
2032
2033/**
2034 * fc_exch_rrq() - Send an ELS RRQ (Reinstate Recovery Qualifier) command
2035 * @ep: The exchange to send the RRQ on
2036 *
2037 * This tells the remote port to stop blocking the use of
2038 * the exchange and the seq_cnt range.
2039 */
2040static void fc_exch_rrq(struct fc_exch *ep)
2041{
2042	struct fc_lport *lport;
2043	struct fc_els_rrq *rrq;
2044	struct fc_frame *fp;
2045	u32 did;
2046
2047	lport = ep->lp;
2048
2049	fp = fc_frame_alloc(lport, sizeof(*rrq));
2050	if (!fp)
2051		goto retry;
2052
2053	rrq = fc_frame_payload_get(fp, sizeof(*rrq));
2054	memset(rrq, 0, sizeof(*rrq));
2055	rrq->rrq_cmd = ELS_RRQ;
2056	hton24(rrq->rrq_s_id, ep->sid);
2057	rrq->rrq_ox_id = htons(ep->oxid);
2058	rrq->rrq_rx_id = htons(ep->rxid);
2059
2060	did = ep->did;
2061	if (ep->esb_stat & ESB_ST_RESP)
2062		did = ep->sid;
2063
2064	fc_fill_fc_hdr(fp, FC_RCTL_ELS_REQ, did,
2065		       lport->port_id, FC_TYPE_ELS,
2066		       FC_FC_FIRST_SEQ | FC_FC_END_SEQ | FC_FC_SEQ_INIT, 0);
2067
2068	if (fc_exch_seq_send(lport, fp, fc_exch_rrq_resp, NULL, ep,
2069			     lport->e_d_tov))
2070		return;
2071
2072retry:
2073	spin_lock_bh(&ep->ex_lock);
2074	if (ep->state & (FC_EX_RST_CLEANUP | FC_EX_DONE)) {
2075		spin_unlock_bh(&ep->ex_lock);
2076		/* drop hold for rec qual */
2077		fc_exch_release(ep);
2078		return;
2079	}
2080	ep->esb_stat |= ESB_ST_REC_QUAL;
2081	fc_exch_timer_set_locked(ep, ep->r_a_tov);
2082	spin_unlock_bh(&ep->ex_lock);
2083}
2084
2085/**
2086 * fc_exch_els_rrq() - Handler for ELS RRQ (Reset Recovery Qualifier) requests
2087 * @fp: The RRQ frame, not freed here.
2088 */
2089static void fc_exch_els_rrq(struct fc_frame *fp)
2090{
2091	struct fc_lport *lport;
2092	struct fc_exch *ep = NULL;	/* request or subject exchange */
2093	struct fc_els_rrq *rp;
2094	u32 sid;
2095	u16 xid;
2096	enum fc_els_rjt_explan explan;
2097
2098	lport = fr_dev(fp);
2099	rp = fc_frame_payload_get(fp, sizeof(*rp));
2100	explan = ELS_EXPL_INV_LEN;
2101	if (!rp)
2102		goto reject;
2103
2104	/*
2105	 * lookup subject exchange.
2106	 */
2107	sid = ntoh24(rp->rrq_s_id);		/* subject source */
2108	xid = fc_host_port_id(lport->host) == sid ?
2109			ntohs(rp->rrq_ox_id) : ntohs(rp->rrq_rx_id);
2110	ep = fc_exch_lookup(lport, xid);
2111	explan = ELS_EXPL_OXID_RXID;
2112	if (!ep)
2113		goto reject;
2114	spin_lock_bh(&ep->ex_lock);
2115	if (ep->oxid != ntohs(rp->rrq_ox_id))
2116		goto unlock_reject;
2117	if (ep->rxid != ntohs(rp->rrq_rx_id) &&
2118	    ep->rxid != FC_XID_UNKNOWN)
2119		goto unlock_reject;
2120	explan = ELS_EXPL_SID;
2121	if (ep->sid != sid)
2122		goto unlock_reject;
2123
2124	/*
2125	 * Clear Recovery Qualifier state, and cancel timer if complete.
2126	 */
2127	if (ep->esb_stat & ESB_ST_REC_QUAL) {
2128		ep->esb_stat &= ~ESB_ST_REC_QUAL;
2129		atomic_dec(&ep->ex_refcnt);	/* drop hold for rec qual */
2130	}
2131	if (ep->esb_stat & ESB_ST_COMPLETE) {
2132		if (cancel_delayed_work(&ep->timeout_work))
2133			atomic_dec(&ep->ex_refcnt);	/* drop timer hold */
2134	}
2135
2136	spin_unlock_bh(&ep->ex_lock);
2137
2138	/*
2139	 * Send LS_ACC.
2140	 */
2141	fc_seq_ls_acc(fp);
2142	goto out;
2143
2144unlock_reject:
2145	spin_unlock_bh(&ep->ex_lock);
2146reject:
2147	fc_seq_ls_rjt(fp, ELS_RJT_LOGIC, explan);
2148out:
2149	if (ep)
2150		fc_exch_release(ep);	/* drop hold from fc_exch_find */
2151}
2152
2153/**
2154 * fc_exch_mgr_add() - Add an exchange manager to a local port's list of EMs
2155 * @lport: The local port to add the exchange manager to
2156 * @mp:	   The exchange manager to be added to the local port
2157 * @match: The match routine that indicates when this EM should be used
2158 */
2159struct fc_exch_mgr_anchor *fc_exch_mgr_add(struct fc_lport *lport,
2160					   struct fc_exch_mgr *mp,
2161					   bool (*match)(struct fc_frame *))
2162{
2163	struct fc_exch_mgr_anchor *ema;
2164
2165	ema = kmalloc(sizeof(*ema), GFP_ATOMIC);
2166	if (!ema)
2167		return ema;
2168
2169	ema->mp = mp;
2170	ema->match = match;
2171	/* add EM anchor to EM anchors list */
2172	list_add_tail(&ema->ema_list, &lport->ema_list);
2173	kref_get(&mp->kref);
2174	return ema;
2175}
2176EXPORT_SYMBOL(fc_exch_mgr_add);
2177
2178/**
2179 * fc_exch_mgr_destroy() - Destroy an exchange manager
2180 * @kref: The reference to the EM to be destroyed
2181 */
2182static void fc_exch_mgr_destroy(struct kref *kref)
2183{
2184	struct fc_exch_mgr *mp = container_of(kref, struct fc_exch_mgr, kref);
2185
2186	mempool_destroy(mp->ep_pool);
2187	free_percpu(mp->pool);
2188	kfree(mp);
2189}
2190
2191/**
2192 * fc_exch_mgr_del() - Delete an EM from a local port's list
2193 * @ema: The exchange manager anchor identifying the EM to be deleted
2194 */
2195void fc_exch_mgr_del(struct fc_exch_mgr_anchor *ema)
2196{
2197	/* remove EM anchor from EM anchors list */
2198	list_del(&ema->ema_list);
2199	kref_put(&ema->mp->kref, fc_exch_mgr_destroy);
2200	kfree(ema);
2201}
2202EXPORT_SYMBOL(fc_exch_mgr_del);
2203
2204/**
2205 * fc_exch_mgr_list_clone() - Share all exchange manager objects
2206 * @src: Source lport to clone exchange managers from
2207 * @dst: New lport that takes references to all the exchange managers
2208 */
2209int fc_exch_mgr_list_clone(struct fc_lport *src, struct fc_lport *dst)
2210{
2211	struct fc_exch_mgr_anchor *ema, *tmp;
2212
2213	list_for_each_entry(ema, &src->ema_list, ema_list) {
2214		if (!fc_exch_mgr_add(dst, ema->mp, ema->match))
2215			goto err;
2216	}
2217	return 0;
2218err:
2219	list_for_each_entry_safe(ema, tmp, &dst->ema_list, ema_list)
2220		fc_exch_mgr_del(ema);
2221	return -ENOMEM;
2222}
2223EXPORT_SYMBOL(fc_exch_mgr_list_clone);
2224
2225/**
2226 * fc_exch_mgr_alloc() - Allocate an exchange manager
2227 * @lport:   The local port that the new EM will be associated with
2228 * @class:   The default FC class for new exchanges
2229 * @min_xid: The minimum XID for exchanges from the new EM
2230 * @max_xid: The maximum XID for exchanges from the new EM
2231 * @match:   The match routine for the new EM
2232 */
2233struct fc_exch_mgr *fc_exch_mgr_alloc(struct fc_lport *lport,
2234				      enum fc_class class,
2235				      u16 min_xid, u16 max_xid,
2236				      bool (*match)(struct fc_frame *))
2237{
2238	struct fc_exch_mgr *mp;
2239	u16 pool_exch_range;
2240	size_t pool_size;
2241	unsigned int cpu;
2242	struct fc_exch_pool *pool;
2243
2244	if (max_xid <= min_xid || max_xid == FC_XID_UNKNOWN ||
2245	    (min_xid & fc_cpu_mask) != 0) {
2246		FC_LPORT_DBG(lport, "Invalid min_xid 0x:%x and max_xid 0x:%x\n",
2247			     min_xid, max_xid);
2248		return NULL;
2249	}
2250
2251	/*
2252	 * allocate memory for EM
2253	 */
2254	mp = kzalloc(sizeof(struct fc_exch_mgr), GFP_ATOMIC);
2255	if (!mp)
2256		return NULL;
2257
2258	mp->class = class;
2259	/* adjust em exch xid range for offload */
2260	mp->min_xid = min_xid;
2261	mp->max_xid = max_xid;
 
 
 
 
 
 
 
 
 
 
 
2262
2263	mp->ep_pool = mempool_create_slab_pool(2, fc_em_cachep);
2264	if (!mp->ep_pool)
2265		goto free_mp;
2266
2267	/*
2268	 * Setup per cpu exch pool with entire exchange id range equally
2269	 * divided across all cpus. The exch pointers array memory is
2270	 * allocated for exch range per pool.
2271	 */
2272	pool_exch_range = (mp->max_xid - mp->min_xid + 1) / (fc_cpu_mask + 1);
2273	mp->pool_max_index = pool_exch_range - 1;
2274
2275	/*
2276	 * Allocate and initialize per cpu exch pool
2277	 */
2278	pool_size = sizeof(*pool) + pool_exch_range * sizeof(struct fc_exch *);
2279	mp->pool = __alloc_percpu(pool_size, __alignof__(struct fc_exch_pool));
2280	if (!mp->pool)
2281		goto free_mempool;
2282	for_each_possible_cpu(cpu) {
2283		pool = per_cpu_ptr(mp->pool, cpu);
 
2284		pool->left = FC_XID_UNKNOWN;
2285		pool->right = FC_XID_UNKNOWN;
2286		spin_lock_init(&pool->lock);
2287		INIT_LIST_HEAD(&pool->ex_list);
2288	}
2289
2290	kref_init(&mp->kref);
2291	if (!fc_exch_mgr_add(lport, mp, match)) {
2292		free_percpu(mp->pool);
2293		goto free_mempool;
2294	}
2295
2296	/*
2297	 * Above kref_init() sets mp->kref to 1 and then
2298	 * call to fc_exch_mgr_add incremented mp->kref again,
2299	 * so adjust that extra increment.
2300	 */
2301	kref_put(&mp->kref, fc_exch_mgr_destroy);
2302	return mp;
2303
2304free_mempool:
2305	mempool_destroy(mp->ep_pool);
2306free_mp:
2307	kfree(mp);
2308	return NULL;
2309}
2310EXPORT_SYMBOL(fc_exch_mgr_alloc);
2311
2312/**
2313 * fc_exch_mgr_free() - Free all exchange managers on a local port
2314 * @lport: The local port whose EMs are to be freed
2315 */
2316void fc_exch_mgr_free(struct fc_lport *lport)
2317{
2318	struct fc_exch_mgr_anchor *ema, *next;
2319
2320	flush_workqueue(fc_exch_workqueue);
2321	list_for_each_entry_safe(ema, next, &lport->ema_list, ema_list)
2322		fc_exch_mgr_del(ema);
2323}
2324EXPORT_SYMBOL(fc_exch_mgr_free);
2325
2326/**
2327 * fc_find_ema() - Lookup and return appropriate Exchange Manager Anchor depending
2328 * upon 'xid'.
2329 * @f_ctl: f_ctl
2330 * @lport: The local port the frame was received on
2331 * @fh: The received frame header
2332 */
2333static struct fc_exch_mgr_anchor *fc_find_ema(u32 f_ctl,
2334					      struct fc_lport *lport,
2335					      struct fc_frame_header *fh)
2336{
2337	struct fc_exch_mgr_anchor *ema;
2338	u16 xid;
2339
2340	if (f_ctl & FC_FC_EX_CTX)
2341		xid = ntohs(fh->fh_ox_id);
2342	else {
2343		xid = ntohs(fh->fh_rx_id);
2344		if (xid == FC_XID_UNKNOWN)
2345			return list_entry(lport->ema_list.prev,
2346					  typeof(*ema), ema_list);
2347	}
2348
2349	list_for_each_entry(ema, &lport->ema_list, ema_list) {
2350		if ((xid >= ema->mp->min_xid) &&
2351		    (xid <= ema->mp->max_xid))
2352			return ema;
2353	}
2354	return NULL;
2355}
2356/**
2357 * fc_exch_recv() - Handler for received frames
2358 * @lport: The local port the frame was received on
2359 * @fp:	The received frame
2360 */
2361void fc_exch_recv(struct fc_lport *lport, struct fc_frame *fp)
2362{
2363	struct fc_frame_header *fh = fc_frame_header_get(fp);
2364	struct fc_exch_mgr_anchor *ema;
2365	u32 f_ctl;
2366
2367	/* lport lock ? */
2368	if (!lport || lport->state == LPORT_ST_DISABLED) {
2369		FC_LPORT_DBG(lport, "Receiving frames for an lport that "
2370			     "has not been initialized correctly\n");
2371		fc_frame_free(fp);
2372		return;
2373	}
2374
2375	f_ctl = ntoh24(fh->fh_f_ctl);
2376	ema = fc_find_ema(f_ctl, lport, fh);
2377	if (!ema) {
2378		FC_LPORT_DBG(lport, "Unable to find Exchange Manager Anchor,"
2379				    "fc_ctl <0x%x>, xid <0x%x>\n",
2380				     f_ctl,
2381				     (f_ctl & FC_FC_EX_CTX) ?
2382				     ntohs(fh->fh_ox_id) :
2383				     ntohs(fh->fh_rx_id));
2384		fc_frame_free(fp);
2385		return;
2386	}
2387
2388	/*
2389	 * If frame is marked invalid, just drop it.
2390	 */
2391	switch (fr_eof(fp)) {
2392	case FC_EOF_T:
2393		if (f_ctl & FC_FC_END_SEQ)
2394			skb_trim(fp_skb(fp), fr_len(fp) - FC_FC_FILL(f_ctl));
2395		/* fall through */
2396	case FC_EOF_N:
2397		if (fh->fh_type == FC_TYPE_BLS)
2398			fc_exch_recv_bls(ema->mp, fp);
2399		else if ((f_ctl & (FC_FC_EX_CTX | FC_FC_SEQ_CTX)) ==
2400			 FC_FC_EX_CTX)
2401			fc_exch_recv_seq_resp(ema->mp, fp);
2402		else if (f_ctl & FC_FC_SEQ_CTX)
2403			fc_exch_recv_resp(ema->mp, fp);
2404		else	/* no EX_CTX and no SEQ_CTX */
2405			fc_exch_recv_req(lport, ema->mp, fp);
2406		break;
2407	default:
2408		FC_LPORT_DBG(lport, "dropping invalid frame (eof %x)",
2409			     fr_eof(fp));
2410		fc_frame_free(fp);
2411	}
2412}
2413EXPORT_SYMBOL(fc_exch_recv);
2414
2415/**
2416 * fc_exch_init() - Initialize the exchange layer for a local port
2417 * @lport: The local port to initialize the exchange layer for
2418 */
2419int fc_exch_init(struct fc_lport *lport)
2420{
2421	if (!lport->tt.seq_start_next)
2422		lport->tt.seq_start_next = fc_seq_start_next;
2423
2424	if (!lport->tt.seq_set_resp)
2425		lport->tt.seq_set_resp = fc_seq_set_resp;
2426
2427	if (!lport->tt.exch_seq_send)
2428		lport->tt.exch_seq_send = fc_exch_seq_send;
2429
2430	if (!lport->tt.seq_send)
2431		lport->tt.seq_send = fc_seq_send;
2432
2433	if (!lport->tt.seq_els_rsp_send)
2434		lport->tt.seq_els_rsp_send = fc_seq_els_rsp_send;
2435
2436	if (!lport->tt.exch_done)
2437		lport->tt.exch_done = fc_exch_done;
2438
2439	if (!lport->tt.exch_mgr_reset)
2440		lport->tt.exch_mgr_reset = fc_exch_mgr_reset;
2441
2442	if (!lport->tt.seq_exch_abort)
2443		lport->tt.seq_exch_abort = fc_seq_exch_abort;
2444
2445	if (!lport->tt.seq_assign)
2446		lport->tt.seq_assign = fc_seq_assign;
2447
2448	if (!lport->tt.seq_release)
2449		lport->tt.seq_release = fc_seq_release;
2450
2451	return 0;
2452}
2453EXPORT_SYMBOL(fc_exch_init);
2454
2455/**
2456 * fc_setup_exch_mgr() - Setup an exchange manager
2457 */
2458int fc_setup_exch_mgr(void)
2459{
2460	fc_em_cachep = kmem_cache_create("libfc_em", sizeof(struct fc_exch),
2461					 0, SLAB_HWCACHE_ALIGN, NULL);
2462	if (!fc_em_cachep)
2463		return -ENOMEM;
2464
2465	/*
2466	 * Initialize fc_cpu_mask and fc_cpu_order. The
2467	 * fc_cpu_mask is set for nr_cpu_ids rounded up
2468	 * to order of 2's * power and order is stored
2469	 * in fc_cpu_order as this is later required in
2470	 * mapping between an exch id and exch array index
2471	 * in per cpu exch pool.
2472	 *
2473	 * This round up is required to align fc_cpu_mask
2474	 * to exchange id's lower bits such that all incoming
2475	 * frames of an exchange gets delivered to the same
2476	 * cpu on which exchange originated by simple bitwise
2477	 * AND operation between fc_cpu_mask and exchange id.
2478	 */
2479	fc_cpu_mask = 1;
2480	fc_cpu_order = 0;
2481	while (fc_cpu_mask < nr_cpu_ids) {
2482		fc_cpu_mask <<= 1;
2483		fc_cpu_order++;
2484	}
2485	fc_cpu_mask--;
2486
2487	fc_exch_workqueue = create_singlethread_workqueue("fc_exch_workqueue");
2488	if (!fc_exch_workqueue)
2489		goto err;
2490	return 0;
2491err:
2492	kmem_cache_destroy(fc_em_cachep);
2493	return -ENOMEM;
2494}
2495
2496/**
2497 * fc_destroy_exch_mgr() - Destroy an exchange manager
2498 */
2499void fc_destroy_exch_mgr(void)
2500{
2501	destroy_workqueue(fc_exch_workqueue);
2502	kmem_cache_destroy(fc_em_cachep);
2503}