Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

Conflicts:

	arch/x86/kernel/io_apic.c

1 files changed, 1970 insertions, 0 deletions

diff --git a/drivers/scsi/libfc/fc_exch.c b/drivers/scsi/libfc/fc_exch.c
new file mode 100644
index 000000000000..66db08a5f27f
--- /dev/null
+++ b/drivers/scsi/libfc/fc_exch.c
@@ -0,0 +1,1970 @@
+/*
+ * Copyright(c) 2007 Intel Corporation. All rights reserved.
+ * Copyright(c) 2008 Red Hat, Inc.  All rights reserved.
+ * Copyright(c) 2008 Mike Christie
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Maintained at www.Open-FCoE.org
+ */
+
+/*
+ * Fibre Channel exchange and sequence handling.
+ */
+
+#include <linux/timer.h>
+#include <linux/gfp.h>
+#include <linux/err.h>
+
+#include <scsi/fc/fc_fc2.h>
+
+#include <scsi/libfc.h>
+#include <scsi/fc_encode.h>
+
+#define	  FC_DEF_R_A_TOV      (10 * 1000) /* resource allocation timeout */
+
+/*
+ * fc_exch_debug can be set in debugger or at compile time to get more logs.
+ */
+static int fc_exch_debug;
+
+#define FC_DEBUG_EXCH(fmt...)			\
+	do {					\
+		if (fc_exch_debug)		\
+			FC_DBG(fmt);		\
+	} while (0)
+
+static struct kmem_cache *fc_em_cachep;	/* cache for exchanges */
+
+/*
+ * Structure and function definitions for managing Fibre Channel Exchanges
+ * and Sequences.
+ *
+ * The three primary structures used here are fc_exch_mgr, fc_exch, and fc_seq.
+ *
+ * fc_exch_mgr holds the exchange state for an N port
+ *
+ * fc_exch holds state for one exchange and links to its active sequence.
+ *
+ * fc_seq holds the state for an individual sequence.
+ */
+
+/*
+ * Exchange manager.
+ *
+ * This structure is the center for creating exchanges and sequences.
+ * It manages the allocation of exchange IDs.
+ */
+struct fc_exch_mgr {
+	enum fc_class	class;		/* default class for sequences */
+	spinlock_t	em_lock;	/* exchange manager lock,
+					   must be taken before ex_lock */
+	u16		last_xid;	/* last allocated exchange ID */
+	u16		min_xid;	/* min exchange ID */
+	u16		max_xid;	/* max exchange ID */
+	u16		max_read;	/* max exchange ID for read */
+	u16		last_read;	/* last xid allocated for read */
+	u32	total_exches;		/* total allocated exchanges */
+	struct list_head	ex_list;	/* allocated exchanges list */
+	struct fc_lport	*lp;		/* fc device instance */
+	mempool_t	*ep_pool;	/* reserve ep's */
+
+	/*
+	 * currently exchange mgr stats are updated but not used.
+	 * either stats can be expose via sysfs or remove them
+	 * all together if not used XXX
+	 */
+	struct {
+		atomic_t no_free_exch;
+		atomic_t no_free_exch_xid;
+		atomic_t xid_not_found;
+		atomic_t xid_busy;
+		atomic_t seq_not_found;
+		atomic_t non_bls_resp;
+	} stats;
+	struct fc_exch **exches;	/* for exch pointers indexed by xid */
+};
+#define	fc_seq_exch(sp) container_of(sp, struct fc_exch, seq)
+
+static void fc_exch_rrq(struct fc_exch *);
+static void fc_seq_ls_acc(struct fc_seq *);
+static void fc_seq_ls_rjt(struct fc_seq *, enum fc_els_rjt_reason,
+			  enum fc_els_rjt_explan);
+static void fc_exch_els_rec(struct fc_seq *, struct fc_frame *);
+static void fc_exch_els_rrq(struct fc_seq *, struct fc_frame *);
+static struct fc_seq *fc_seq_start_next_locked(struct fc_seq *sp);
+
+/*
+ * Internal implementation notes.
+ *
+ * The exchange manager is one by default in libfc but LLD may choose
+ * to have one per CPU. The sequence manager is one per exchange manager
+ * and currently never separated.
+ *
+ * Section 9.8 in FC-FS-2 specifies:  "The SEQ_ID is a one-byte field
+ * assigned by the Sequence Initiator that shall be unique for a specific
+ * D_ID and S_ID pair while the Sequence is open."   Note that it isn't
+ * qualified by exchange ID, which one might think it would be.
+ * In practice this limits the number of open sequences and exchanges to 256
+ * per session.	 For most targets we could treat this limit as per exchange.
+ *
+ * The exchange and its sequence are freed when the last sequence is received.
+ * It's possible for the remote port to leave an exchange open without
+ * sending any sequences.
+ *
+ * Notes on reference counts:
+ *
+ * Exchanges are reference counted and exchange gets freed when the reference
+ * count becomes zero.
+ *
+ * Timeouts:
+ * Sequences are timed out for E_D_TOV and R_A_TOV.
+ *
+ * Sequence event handling:
+ *
+ * The following events may occur on initiator sequences:
+ *
+ *	Send.
+ *	    For now, the whole thing is sent.
+ *	Receive ACK
+ *	    This applies only to class F.
+ *	    The sequence is marked complete.
+ *	ULP completion.
+ *	    The upper layer calls fc_exch_done() when done
+ *	    with exchange and sequence tuple.
+ *	RX-inferred completion.
+ *	    When we receive the next sequence on the same exchange, we can
+ *	    retire the previous sequence ID.  (XXX not implemented).
+ *	Timeout.
+ *	    R_A_TOV frees the sequence ID.  If we're waiting for ACK,
+ *	    E_D_TOV causes abort and calls upper layer response handler
+ *	    with FC_EX_TIMEOUT error.
+ *	Receive RJT
+ *	    XXX defer.
+ *	Send ABTS
+ *	    On timeout.
+ *
+ * The following events may occur on recipient sequences:
+ *
+ *	Receive
+ *	    Allocate sequence for first frame received.
+ *	    Hold during receive handler.
+ *	    Release when final frame received.
+ *	    Keep status of last N of these for the ELS RES command.  XXX TBD.
+ *	Receive ABTS
+ *	    Deallocate sequence
+ *	Send RJT
+ *	    Deallocate
+ *
+ * For now, we neglect conditions where only part of a sequence was
+ * received or transmitted, or where out-of-order receipt is detected.
+ */
+
+/*
+ * Locking notes:
+ *
+ * The EM code run in a per-CPU worker thread.
+ *
+ * To protect against concurrency between a worker thread code and timers,
+ * sequence allocation and deallocation must be locked.
+ *  - exchange refcnt can be done atomicly without locks.
+ *  - sequence allocation must be locked by exch lock.
+ *  - If the em_lock and ex_lock must be taken at the same time, then the
+ *    em_lock must be taken before the ex_lock.
+ */
+
+/*
+ * opcode names for debugging.
+ */
+static char *fc_exch_rctl_names[] = FC_RCTL_NAMES_INIT;
+
+#define FC_TABLE_SIZE(x)   (sizeof(x) / sizeof(x[0]))
+
+static inline const char *fc_exch_name_lookup(unsigned int op, char **table,
+					      unsigned int max_index)
+{
+	const char *name = NULL;
+
+	if (op < max_index)
+		name = table[op];
+	if (!name)
+		name = "unknown";
+	return name;
+}
+
+static const char *fc_exch_rctl_name(unsigned int op)
+{
+	return fc_exch_name_lookup(op, fc_exch_rctl_names,
+				   FC_TABLE_SIZE(fc_exch_rctl_names));
+}
+
+/*
+ * Hold an exchange - keep it from being freed.
+ */
+static void fc_exch_hold(struct fc_exch *ep)
+{
+	atomic_inc(&ep->ex_refcnt);
+}
+
+/*
+ * setup fc hdr by initializing few more FC header fields and sof/eof.
+ * Initialized fields by this func:
+ *	- fh_ox_id, fh_rx_id, fh_seq_id, fh_seq_cnt
+ *	- sof and eof
+ */
+static void fc_exch_setup_hdr(struct fc_exch *ep, struct fc_frame *fp,
+			      u32 f_ctl)
+{
+	struct fc_frame_header *fh = fc_frame_header_get(fp);
+	u16 fill;
+
+	fr_sof(fp) = ep->class;
+	if (ep->seq.cnt)
+		fr_sof(fp) = fc_sof_normal(ep->class);
+
+	if (f_ctl & FC_FC_END_SEQ) {
+		fr_eof(fp) = FC_EOF_T;
+		if (fc_sof_needs_ack(ep->class))
+			fr_eof(fp) = FC_EOF_N;
+		/*
+		 * Form f_ctl.
+		 * The number of fill bytes to make the length a 4-byte
+		 * multiple is the low order 2-bits of the f_ctl.
+		 * The fill itself will have been cleared by the frame
+		 * allocation.
+		 * After this, the length will be even, as expected by
+		 * the transport.
+		 */
+		fill = fr_len(fp) & 3;
+		if (fill) {
+			fill = 4 - fill;
+			/* TODO, this may be a problem with fragmented skb */
+			skb_put(fp_skb(fp), fill);
+			hton24(fh->fh_f_ctl, f_ctl | fill);
+		}
+	} else {
+		WARN_ON(fr_len(fp) % 4 != 0);	/* no pad to non last frame */
+		fr_eof(fp) = FC_EOF_N;
+	}
+
+	/*
+	 * Initialize remainig fh fields
+	 * from fc_fill_fc_hdr
+	 */
+	fh->fh_ox_id = htons(ep->oxid);
+	fh->fh_rx_id = htons(ep->rxid);
+	fh->fh_seq_id = ep->seq.id;
+	fh->fh_seq_cnt = htons(ep->seq.cnt);
+}
+
+
+/*
+ * Release a reference to an exchange.
+ * If the refcnt goes to zero and the exchange is complete, it is freed.
+ */
+static void fc_exch_release(struct fc_exch *ep)
+{
+	struct fc_exch_mgr *mp;
+
+	if (atomic_dec_and_test(&ep->ex_refcnt)) {
+		mp = ep->em;
+		if (ep->destructor)
+			ep->destructor(&ep->seq, ep->arg);
+		if (ep->lp->tt.exch_put)
+			ep->lp->tt.exch_put(ep->lp, mp, ep->xid);
+		WARN_ON(!ep->esb_stat & ESB_ST_COMPLETE);
+		mempool_free(ep, mp->ep_pool);
+	}
+}
+
+static int fc_exch_done_locked(struct fc_exch *ep)
+{
+	int rc = 1;
+
+	/*
+	 * We must check for completion in case there are two threads
+	 * tyring to complete this. But the rrq code will reuse the
+	 * ep, and in that case we only clear the resp and set it as
+	 * complete, so it can be reused by the timer to send the rrq.
+	 */
+	ep->resp = NULL;
+	if (ep->state & FC_EX_DONE)
+		return rc;
+	ep->esb_stat |= ESB_ST_COMPLETE;
+
+	if (!(ep->esb_stat & ESB_ST_REC_QUAL)) {
+		ep->state |= FC_EX_DONE;
+		if (cancel_delayed_work(&ep->timeout_work))
+			atomic_dec(&ep->ex_refcnt); /* drop hold for timer */
+		rc = 0;
+	}
+	return rc;
+}
+
+static void fc_exch_mgr_delete_ep(struct fc_exch *ep)
+{
+	struct fc_exch_mgr *mp;
+
+	mp = ep->em;
+	spin_lock_bh(&mp->em_lock);
+	WARN_ON(mp->total_exches <= 0);
+	mp->total_exches--;
+	mp->exches[ep->xid - mp->min_xid] = NULL;
+	list_del(&ep->ex_list);
+	spin_unlock_bh(&mp->em_lock);
+	fc_exch_release(ep);	/* drop hold for exch in mp */
+}
+
+/*
+ * Internal version of fc_exch_timer_set - used with lock held.
+ */
+static inline void fc_exch_timer_set_locked(struct fc_exch *ep,
+					    unsigned int timer_msec)
+{
+	if (ep->state & (FC_EX_RST_CLEANUP | FC_EX_DONE))
+		return;
+
+	FC_DEBUG_EXCH("Exchange (%4x) timed out, notifying the upper layer\n",
+		      ep->xid);
+	if (schedule_delayed_work(&ep->timeout_work,
+				  msecs_to_jiffies(timer_msec)))
+		fc_exch_hold(ep);		/* hold for timer */
+}
+
+/*
+ * Set timer for an exchange.
+ * The time is a minimum delay in milliseconds until the timer fires.
+ * Used for upper level protocols to time out the exchange.
+ * The timer is cancelled when it fires or when the exchange completes.
+ * Returns non-zero if a timer couldn't be allocated.
+ */
+static void fc_exch_timer_set(struct fc_exch *ep, unsigned int timer_msec)
+{
+	spin_lock_bh(&ep->ex_lock);
+	fc_exch_timer_set_locked(ep, timer_msec);
+	spin_unlock_bh(&ep->ex_lock);
+}
+
+int fc_seq_exch_abort(const struct fc_seq *req_sp, unsigned int timer_msec)
+{
+	struct fc_seq *sp;
+	struct fc_exch *ep;
+	struct fc_frame *fp;
+	int error;
+
+	ep = fc_seq_exch(req_sp);
+
+	spin_lock_bh(&ep->ex_lock);
+	if (ep->esb_stat & (ESB_ST_COMPLETE | ESB_ST_ABNORMAL) ||
+	    ep->state & (FC_EX_DONE | FC_EX_RST_CLEANUP)) {
+		spin_unlock_bh(&ep->ex_lock);
+		return -ENXIO;
+	}
+
+	/*
+	 * Send the abort on a new sequence if possible.
+	 */
+	sp = fc_seq_start_next_locked(&ep->seq);
+	if (!sp) {
+		spin_unlock_bh(&ep->ex_lock);
+		return -ENOMEM;
+	}
+
+	ep->esb_stat |= ESB_ST_SEQ_INIT | ESB_ST_ABNORMAL;
+	if (timer_msec)
+		fc_exch_timer_set_locked(ep, timer_msec);
+	spin_unlock_bh(&ep->ex_lock);
+
+	/*
+	 * If not logged into the fabric, don't send ABTS but leave
+	 * sequence active until next timeout.
+	 */
+	if (!ep->sid)
+		return 0;
+
+	/*
+	 * Send an abort for the sequence that timed out.
+	 */
+	fp = fc_frame_alloc(ep->lp, 0);
+	if (fp) {
+		fc_fill_fc_hdr(fp, FC_RCTL_BA_ABTS, ep->did, ep->sid,
+			       FC_TYPE_BLS, FC_FC_END_SEQ | FC_FC_SEQ_INIT, 0);
+		error = fc_seq_send(ep->lp, sp, fp);
+	} else
+		error = -ENOBUFS;
+	return error;
+}
+EXPORT_SYMBOL(fc_seq_exch_abort);
+
+/*
+ * Exchange timeout - handle exchange timer expiration.
+ * The timer will have been cancelled before this is called.
+ */
+static void fc_exch_timeout(struct work_struct *work)
+{
+	struct fc_exch *ep = container_of(work, struct fc_exch,
+					  timeout_work.work);
+	struct fc_seq *sp = &ep->seq;
+	void (*resp)(struct fc_seq *, struct fc_frame *fp, void *arg);
+	void *arg;
+	u32 e_stat;
+	int rc = 1;
+
+	spin_lock_bh(&ep->ex_lock);
+	if (ep->state & (FC_EX_RST_CLEANUP | FC_EX_DONE))
+		goto unlock;
+
+	e_stat = ep->esb_stat;
+	if (e_stat & ESB_ST_COMPLETE) {
+		ep->esb_stat = e_stat & ~ESB_ST_REC_QUAL;
+		if (e_stat & ESB_ST_REC_QUAL)
+			fc_exch_rrq(ep);
+		spin_unlock_bh(&ep->ex_lock);
+		goto done;
+	} else {
+		resp = ep->resp;
+		arg = ep->arg;
+		ep->resp = NULL;
+		if (e_stat & ESB_ST_ABNORMAL)
+			rc = fc_exch_done_locked(ep);
+		spin_unlock_bh(&ep->ex_lock);
+		if (!rc)
+			fc_exch_mgr_delete_ep(ep);
+		if (resp)
+			resp(sp, ERR_PTR(-FC_EX_TIMEOUT), arg);
+		fc_seq_exch_abort(sp, 2 * ep->r_a_tov);
+		goto done;
+	}
+unlock:
+	spin_unlock_bh(&ep->ex_lock);
+done:
+	/*
+	 * This release matches the hold taken when the timer was set.
+	 */
+	fc_exch_release(ep);
+}
+
+/*
+ * Allocate a sequence.
+ *
+ * We don't support multiple originated sequences on the same exchange.
+ * By implication, any previously originated sequence on this exchange
+ * is complete, and we reallocate the same sequence.
+ */
+static struct fc_seq *fc_seq_alloc(struct fc_exch *ep, u8 seq_id)
+{
+	struct fc_seq *sp;
+
+	sp = &ep->seq;
+	sp->ssb_stat = 0;
+	sp->cnt = 0;
+	sp->id = seq_id;
+	return sp;
+}
+
+/*
+ * fc_em_alloc_xid - returns an xid based on request type
+ * @lp : ptr to associated lport
+ * @fp : ptr to the assocated frame
+ *
+ * check the associated fc_fsp_pkt to get scsi command type and
+ * command direction to decide from which range this exch id
+ * will be allocated from.
+ *
+ * Returns : 0 or an valid xid
+ */
+static u16 fc_em_alloc_xid(struct fc_exch_mgr *mp, const struct fc_frame *fp)
+{
+	u16 xid, min, max;
+	u16 *plast;
+	struct fc_exch *ep = NULL;
+
+	if (mp->max_read) {
+		if (fc_frame_is_read(fp)) {
+			min = mp->min_xid;
+			max = mp->max_read;
+			plast = &mp->last_read;
+		} else {
+			min = mp->max_read + 1;
+			max = mp->max_xid;
+			plast = &mp->last_xid;
+		}
+	} else {
+		min = mp->min_xid;
+		max = mp->max_xid;
+		plast = &mp->last_xid;
+	}
+	xid = *plast;
+	do {
+		xid = (xid == max) ? min : xid + 1;
+		ep = mp->exches[xid - mp->min_xid];
+	} while ((ep != NULL) && (xid != *plast));
+
+	if (unlikely(ep))
+		xid = 0;
+	else
+		*plast = xid;
+
+	return xid;
+}
+
+/*
+ * fc_exch_alloc - allocate an exchange.
+ * @mp : ptr to the exchange manager
+ * @xid: input xid
+ *
+ * if xid is supplied zero then assign next free exchange ID
+ * from exchange manager, otherwise use supplied xid.
+ * Returns with exch lock held.
+ */
+struct fc_exch *fc_exch_alloc(struct fc_exch_mgr *mp,
+			      struct fc_frame *fp, u16 xid)
+{
+	struct fc_exch *ep;
+
+	/* allocate memory for exchange */
+	ep = mempool_alloc(mp->ep_pool, GFP_ATOMIC);
+	if (!ep) {
+		atomic_inc(&mp->stats.no_free_exch);
+		goto out;
+	}
+	memset(ep, 0, sizeof(*ep));
+
+	spin_lock_bh(&mp->em_lock);
+	/* alloc xid if input xid 0 */
+	if (!xid) {
+		/* alloc a new xid */
+		xid = fc_em_alloc_xid(mp, fp);
+		if (!xid) {
+			printk(KERN_ERR "fc_em_alloc_xid() failed\n");
+			goto err;
+		}
+	}
+
+	fc_exch_hold(ep);	/* hold for exch in mp */
+	spin_lock_init(&ep->ex_lock);
+	/*
+	 * Hold exch lock for caller to prevent fc_exch_reset()
+	 * from releasing exch	while fc_exch_alloc() caller is
+	 * still working on exch.
+	 */
+	spin_lock_bh(&ep->ex_lock);
+
+	mp->exches[xid - mp->min_xid] = ep;
+	list_add_tail(&ep->ex_list, &mp->ex_list);
+	fc_seq_alloc(ep, ep->seq_id++);
+	mp->total_exches++;
+	spin_unlock_bh(&mp->em_lock);
+
+	/*
+	 *  update exchange
+	 */
+	ep->oxid = ep->xid = xid;
+	ep->em = mp;
+	ep->lp = mp->lp;
+	ep->f_ctl = FC_FC_FIRST_SEQ;	/* next seq is first seq */
+	ep->rxid = FC_XID_UNKNOWN;
+	ep->class = mp->class;
+	INIT_DELAYED_WORK(&ep->timeout_work, fc_exch_timeout);
+out:
+	return ep;
+err:
+	spin_unlock_bh(&mp->em_lock);
+	atomic_inc(&mp->stats.no_free_exch_xid);
+	mempool_free(ep, mp->ep_pool);
+	return NULL;
+}
+EXPORT_SYMBOL(fc_exch_alloc);
+
+/*
+ * Lookup and hold an exchange.
+ */
+static struct fc_exch *fc_exch_find(struct fc_exch_mgr *mp, u16 xid)
+{
+	struct fc_exch *ep = NULL;
+
+	if ((xid >= mp->min_xid) && (xid <= mp->max_xid)) {
+		spin_lock_bh(&mp->em_lock);
+		ep = mp->exches[xid - mp->min_xid];
+		if (ep) {
+			fc_exch_hold(ep);
+			WARN_ON(ep->xid != xid);
+		}
+		spin_unlock_bh(&mp->em_lock);
+	}
+	return ep;
+}
+
+void fc_exch_done(struct fc_seq *sp)
+{
+	struct fc_exch *ep = fc_seq_exch(sp);
+	int rc;
+
+	spin_lock_bh(&ep->ex_lock);
+	rc = fc_exch_done_locked(ep);
+	spin_unlock_bh(&ep->ex_lock);
+	if (!rc)
+		fc_exch_mgr_delete_ep(ep);
+}
+EXPORT_SYMBOL(fc_exch_done);
+
+/*
+ * Allocate a new exchange as responder.
+ * Sets the responder ID in the frame header.
+ */
+static struct fc_exch *fc_exch_resp(struct fc_exch_mgr *mp, struct fc_frame *fp)
+{
+	struct fc_exch *ep;
+	struct fc_frame_header *fh;
+	u16 rxid;
+
+	ep = mp->lp->tt.exch_get(mp->lp, fp);
+	if (ep) {
+		ep->class = fc_frame_class(fp);
+
+		/*
+		 * Set EX_CTX indicating we're responding on this exchange.
+		 */
+		ep->f_ctl |= FC_FC_EX_CTX;	/* we're responding */
+		ep->f_ctl &= ~FC_FC_FIRST_SEQ;	/* not new */
+		fh = fc_frame_header_get(fp);
+		ep->sid = ntoh24(fh->fh_d_id);
+		ep->did = ntoh24(fh->fh_s_id);
+		ep->oid = ep->did;
+
+		/*
+		 * Allocated exchange has placed the XID in the
+		 * originator field. Move it to the responder field,
+		 * and set the originator XID from the frame.
+		 */
+		ep->rxid = ep->xid;
+		ep->oxid = ntohs(fh->fh_ox_id);
+		ep->esb_stat |= ESB_ST_RESP | ESB_ST_SEQ_INIT;
+		if ((ntoh24(fh->fh_f_ctl) & FC_FC_SEQ_INIT) == 0)
+			ep->esb_stat &= ~ESB_ST_SEQ_INIT;
+
+		/*
+		 * Set the responder ID in the frame header.
+		 * The old one should've been 0xffff.
+		 * If it isn't, don't assign one.
+		 * Incoming basic link service frames may specify
+		 * a referenced RX_ID.
+		 */
+		if (fh->fh_type != FC_TYPE_BLS) {
+			rxid = ntohs(fh->fh_rx_id);
+			WARN_ON(rxid != FC_XID_UNKNOWN);
+			fh->fh_rx_id = htons(ep->rxid);
+		}
+		fc_exch_hold(ep);	/* hold for caller */
+		spin_unlock_bh(&ep->ex_lock);	/* lock from exch_get */
+	}
+	return ep;
+}
+
+/*
+ * Find a sequence for receive where the other end is originating the sequence.
+ * If fc_pf_rjt_reason is FC_RJT_NONE then this function will have a hold
+ * on the ep that should be released by the caller.
+ */
+static enum fc_pf_rjt_reason
+fc_seq_lookup_recip(struct fc_exch_mgr *mp, struct fc_frame *fp)
+{
+	struct fc_frame_header *fh = fc_frame_header_get(fp);
+	struct fc_exch *ep = NULL;
+	struct fc_seq *sp = NULL;
+	enum fc_pf_rjt_reason reject = FC_RJT_NONE;
+	u32 f_ctl;
+	u16 xid;
+
+	f_ctl = ntoh24(fh->fh_f_ctl);
+	WARN_ON((f_ctl & FC_FC_SEQ_CTX) != 0);
+
+	/*
+	 * Lookup or create the exchange if we will be creating the sequence.
+	 */
+	if (f_ctl & FC_FC_EX_CTX) {
+		xid = ntohs(fh->fh_ox_id);	/* we originated exch */
+		ep = fc_exch_find(mp, xid);
+		if (!ep) {
+			atomic_inc(&mp->stats.xid_not_found);
+			reject = FC_RJT_OX_ID;
+			goto out;
+		}
+		if (ep->rxid == FC_XID_UNKNOWN)
+			ep->rxid = ntohs(fh->fh_rx_id);
+		else if (ep->rxid != ntohs(fh->fh_rx_id)) {
+			reject = FC_RJT_OX_ID;
+			goto rel;
+		}
+	} else {
+		xid = ntohs(fh->fh_rx_id);	/* we are the responder */
+
+		/*
+		 * Special case for MDS issuing an ELS TEST with a
+		 * bad rxid of 0.
+		 * XXX take this out once we do the proper reject.
+		 */
+		if (xid == 0 && fh->fh_r_ctl == FC_RCTL_ELS_REQ &&
+		    fc_frame_payload_op(fp) == ELS_TEST) {
+			fh->fh_rx_id = htons(FC_XID_UNKNOWN);
+			xid = FC_XID_UNKNOWN;
+		}
+
+		/*
+		 * new sequence - find the exchange
+		 */
+		ep = fc_exch_find(mp, xid);
+		if ((f_ctl & FC_FC_FIRST_SEQ) && fc_sof_is_init(fr_sof(fp))) {
+			if (ep) {
+				atomic_inc(&mp->stats.xid_busy);
+				reject = FC_RJT_RX_ID;
+				goto rel;
+			}
+			ep = fc_exch_resp(mp, fp);
+			if (!ep) {
+				reject = FC_RJT_EXCH_EST;	/* XXX */
+				goto out;
+			}
+			xid = ep->xid;	/* get our XID */
+		} else if (!ep) {
+			atomic_inc(&mp->stats.xid_not_found);
+			reject = FC_RJT_RX_ID;	/* XID not found */
+			goto out;
+		}
+	}
+
+	/*
+	 * At this point, we have the exchange held.
+	 * Find or create the sequence.
+	 */
+	if (fc_sof_is_init(fr_sof(fp))) {
+		sp = fc_seq_start_next(&ep->seq);
+		if (!sp) {
+			reject = FC_RJT_SEQ_XS;	/* exchange shortage */
+			goto rel;
+		}
+		sp->id = fh->fh_seq_id;
+		sp->ssb_stat |= SSB_ST_RESP;
+	} else {
+		sp = &ep->seq;
+		if (sp->id != fh->fh_seq_id) {
+			atomic_inc(&mp->stats.seq_not_found);
+			reject = FC_RJT_SEQ_ID;	/* sequence/exch should exist */
+			goto rel;
+		}
+	}
+	WARN_ON(ep != fc_seq_exch(sp));
+
+	if (f_ctl & FC_FC_SEQ_INIT)
+		ep->esb_stat |= ESB_ST_SEQ_INIT;
+
+	fr_seq(fp) = sp;
+out:
+	return reject;
+rel:
+	fc_exch_done(&ep->seq);
+	fc_exch_release(ep);	/* hold from fc_exch_find/fc_exch_resp */
+	return reject;
+}
+
+/*
+ * Find the sequence for a frame being received.
+ * We originated the sequence, so it should be found.
+ * We may or may not have originated the exchange.
+ * Does not hold the sequence for the caller.
+ */
+static struct fc_seq *fc_seq_lookup_orig(struct fc_exch_mgr *mp,
+					 struct fc_frame *fp)
+{
+	struct fc_frame_header *fh = fc_frame_header_get(fp);
+	struct fc_exch *ep;
+	struct fc_seq *sp = NULL;
+	u32 f_ctl;
+	u16 xid;
+
+	f_ctl = ntoh24(fh->fh_f_ctl);
+	WARN_ON((f_ctl & FC_FC_SEQ_CTX) != FC_FC_SEQ_CTX);
+	xid = ntohs((f_ctl & FC_FC_EX_CTX) ? fh->fh_ox_id : fh->fh_rx_id);
+	ep = fc_exch_find(mp, xid);
+	if (!ep)
+		return NULL;
+	if (ep->seq.id == fh->fh_seq_id) {
+		/*
+		 * Save the RX_ID if we didn't previously know it.
+		 */
+		sp = &ep->seq;
+		if ((f_ctl & FC_FC_EX_CTX) != 0 &&
+		    ep->rxid == FC_XID_UNKNOWN) {
+			ep->rxid = ntohs(fh->fh_rx_id);
+		}
+	}
+	fc_exch_release(ep);
+	return sp;
+}
+
+/*
+ * Set addresses for an exchange.
+ * Note this must be done before the first sequence of the exchange is sent.
+ */
+static void fc_exch_set_addr(struct fc_exch *ep,
+			     u32 orig_id, u32 resp_id)
+{
+	ep->oid = orig_id;
+	if (ep->esb_stat & ESB_ST_RESP) {
+		ep->sid = resp_id;
+		ep->did = orig_id;
+	} else {
+		ep->sid = orig_id;
+		ep->did = resp_id;
+	}
+}
+
+static struct fc_seq *fc_seq_start_next_locked(struct fc_seq *sp)
+{
+	struct fc_exch *ep = fc_seq_exch(sp);
+
+	sp = fc_seq_alloc(ep, ep->seq_id++);
+	FC_DEBUG_EXCH("exch %4x f_ctl %6x seq %2x\n",
+		      ep->xid, ep->f_ctl, sp->id);
+	return sp;
+}
+/*
+ * Allocate a new sequence on the same exchange as the supplied sequence.
+ * This will never return NULL.
+ */
+struct fc_seq *fc_seq_start_next(struct fc_seq *sp)
+{
+	struct fc_exch *ep = fc_seq_exch(sp);
+
+	spin_lock_bh(&ep->ex_lock);
+	WARN_ON((ep->esb_stat & ESB_ST_COMPLETE) != 0);
+	sp = fc_seq_start_next_locked(sp);
+	spin_unlock_bh(&ep->ex_lock);
+
+	return sp;
+}
+EXPORT_SYMBOL(fc_seq_start_next);
+
+int fc_seq_send(struct fc_lport *lp, struct fc_seq *sp, struct fc_frame *fp)
+{
+	struct fc_exch *ep;
+	struct fc_frame_header *fh = fc_frame_header_get(fp);
+	int error;
+	u32	f_ctl;
+
+	ep = fc_seq_exch(sp);
+	WARN_ON((ep->esb_stat & ESB_ST_SEQ_INIT) != ESB_ST_SEQ_INIT);
+
+	f_ctl = ntoh24(fh->fh_f_ctl);
+	fc_exch_setup_hdr(ep, fp, f_ctl);
+
+	/*
+	 * update sequence count if this frame is carrying
+	 * multiple FC frames when sequence offload is enabled
+	 * by LLD.
+	 */
+	if (fr_max_payload(fp))
+		sp->cnt += DIV_ROUND_UP((fr_len(fp) - sizeof(*fh)),
+					fr_max_payload(fp));
+	else
+		sp->cnt++;
+
+	/*
+	 * Send the frame.
+	 */
+	error = lp->tt.frame_send(lp, fp);
+
+	/*
+	 * Update the exchange and sequence flags,
+	 * assuming all frames for the sequence have been sent.
+	 * We can only be called to send once for each sequence.
+	 */
+	spin_lock_bh(&ep->ex_lock);
+	ep->f_ctl = f_ctl & ~FC_FC_FIRST_SEQ;	/* not first seq */
+	if (f_ctl & (FC_FC_END_SEQ | FC_FC_SEQ_INIT))
+		ep->esb_stat &= ~ESB_ST_SEQ_INIT;
+	spin_unlock_bh(&ep->ex_lock);
+	return error;
+}
+EXPORT_SYMBOL(fc_seq_send);
+
+void fc_seq_els_rsp_send(struct fc_seq *sp, enum fc_els_cmd els_cmd,
+			 struct fc_seq_els_data *els_data)
+{
+	switch (els_cmd) {
+	case ELS_LS_RJT:
+		fc_seq_ls_rjt(sp, els_data->reason, els_data->explan);
+		break;
+	case ELS_LS_ACC:
+		fc_seq_ls_acc(sp);
+		break;
+	case ELS_RRQ:
+		fc_exch_els_rrq(sp, els_data->fp);
+		break;
+	case ELS_REC:
+		fc_exch_els_rec(sp, els_data->fp);
+		break;
+	default:
+		FC_DBG("Invalid ELS CMD:%x\n", els_cmd);
+	}
+}
+EXPORT_SYMBOL(fc_seq_els_rsp_send);
+
+/*
+ * Send a sequence, which is also the last sequence in the exchange.
+ */
+static void fc_seq_send_last(struct fc_seq *sp, struct fc_frame *fp,
+			     enum fc_rctl rctl, enum fc_fh_type fh_type)
+{
+	u32 f_ctl;
+	struct fc_exch *ep = fc_seq_exch(sp);
+
+	f_ctl = FC_FC_LAST_SEQ | FC_FC_END_SEQ | FC_FC_SEQ_INIT;
+	f_ctl |= ep->f_ctl;
+	fc_fill_fc_hdr(fp, rctl, ep->did, ep->sid, fh_type, f_ctl, 0);
+	fc_seq_send(ep->lp, sp, fp);
+}
+
+/*
+ * Send ACK_1 (or equiv.) indicating we received something.
+ * The frame we're acking is supplied.
+ */
+static void fc_seq_send_ack(struct fc_seq *sp, const struct fc_frame *rx_fp)
+{
+	struct fc_frame *fp;
+	struct fc_frame_header *rx_fh;
+	struct fc_frame_header *fh;
+	struct fc_exch *ep = fc_seq_exch(sp);
+	struct fc_lport *lp = ep->lp;
+	unsigned int f_ctl;
+
+	/*
+	 * Don't send ACKs for class 3.
+	 */
+	if (fc_sof_needs_ack(fr_sof(rx_fp))) {
+		fp = fc_frame_alloc(lp, 0);
+		if (!fp)
+			return;
+
+		fh = fc_frame_header_get(fp);
+		fh->fh_r_ctl = FC_RCTL_ACK_1;
+		fh->fh_type = FC_TYPE_BLS;
+
+		/*
+		 * Form f_ctl by inverting EX_CTX and SEQ_CTX (bits 23, 22).
+		 * Echo FIRST_SEQ, LAST_SEQ, END_SEQ, END_CONN, SEQ_INIT.
+		 * Bits 9-8 are meaningful (retransmitted or unidirectional).
+		 * Last ACK uses bits 7-6 (continue sequence),
+		 * bits 5-4 are meaningful (what kind of ACK to use).
+		 */
+		rx_fh = fc_frame_header_get(rx_fp);
+		f_ctl = ntoh24(rx_fh->fh_f_ctl);
+		f_ctl &= FC_FC_EX_CTX | FC_FC_SEQ_CTX |
+			FC_FC_FIRST_SEQ | FC_FC_LAST_SEQ |
+			FC_FC_END_SEQ | FC_FC_END_CONN | FC_FC_SEQ_INIT |
+			FC_FC_RETX_SEQ | FC_FC_UNI_TX;
+		f_ctl ^= FC_FC_EX_CTX | FC_FC_SEQ_CTX;
+		hton24(fh->fh_f_ctl, f_ctl);
+
+		fc_exch_setup_hdr(ep, fp, f_ctl);
+		fh->fh_seq_id = rx_fh->fh_seq_id;
+		fh->fh_seq_cnt = rx_fh->fh_seq_cnt;
+		fh->fh_parm_offset = htonl(1);	/* ack single frame */
+
+		fr_sof(fp) = fr_sof(rx_fp);
+		if (f_ctl & FC_FC_END_SEQ)
+			fr_eof(fp) = FC_EOF_T;
+		else
+			fr_eof(fp) = FC_EOF_N;
+
+		(void) lp->tt.frame_send(lp, fp);
+	}
+}
+
+/*
+ * Send BLS Reject.
+ * This is for rejecting BA_ABTS only.
+ */
+static void
+fc_exch_send_ba_rjt(struct fc_frame *rx_fp, enum fc_ba_rjt_reason reason,
+		    enum fc_ba_rjt_explan explan)
+{
+	struct fc_frame *fp;
+	struct fc_frame_header *rx_fh;
+	struct fc_frame_header *fh;
+	struct fc_ba_rjt *rp;
+	struct fc_lport *lp;
+	unsigned int f_ctl;
+
+	lp = fr_dev(rx_fp);
+	fp = fc_frame_alloc(lp, sizeof(*rp));
+	if (!fp)
+		return;
+	fh = fc_frame_header_get(fp);
+	rx_fh = fc_frame_header_get(rx_fp);
+
+	memset(fh, 0, sizeof(*fh) + sizeof(*rp));
+
+	rp = fc_frame_payload_get(fp, sizeof(*rp));
+	rp->br_reason = reason;
+	rp->br_explan = explan;
+
+	/*
+	 * seq_id, cs_ctl, df_ctl and param/offset are zero.
+	 */
+	memcpy(fh->fh_s_id, rx_fh->fh_d_id, 3);
+	memcpy(fh->fh_d_id, rx_fh->fh_s_id, 3);
+	fh->fh_ox_id = rx_fh->fh_rx_id;
+	fh->fh_rx_id = rx_fh->fh_ox_id;
+	fh->fh_seq_cnt = rx_fh->fh_seq_cnt;
+	fh->fh_r_ctl = FC_RCTL_BA_RJT;
+	fh->fh_type = FC_TYPE_BLS;
+
+	/*
+	 * Form f_ctl by inverting EX_CTX and SEQ_CTX (bits 23, 22).
+	 * Echo FIRST_SEQ, LAST_SEQ, END_SEQ, END_CONN, SEQ_INIT.
+	 * Bits 9-8 are meaningful (retransmitted or unidirectional).
+	 * Last ACK uses bits 7-6 (continue sequence),
+	 * bits 5-4 are meaningful (what kind of ACK to use).
+	 * Always set LAST_SEQ, END_SEQ.
+	 */
+	f_ctl = ntoh24(rx_fh->fh_f_ctl);
+	f_ctl &= FC_FC_EX_CTX | FC_FC_SEQ_CTX |
+		FC_FC_END_CONN | FC_FC_SEQ_INIT |
+		FC_FC_RETX_SEQ | FC_FC_UNI_TX;
+	f_ctl ^= FC_FC_EX_CTX | FC_FC_SEQ_CTX;
+	f_ctl |= FC_FC_LAST_SEQ | FC_FC_END_SEQ;
+	f_ctl &= ~FC_FC_FIRST_SEQ;
+	hton24(fh->fh_f_ctl, f_ctl);
+
+	fr_sof(fp) = fc_sof_class(fr_sof(rx_fp));
+	fr_eof(fp) = FC_EOF_T;
+	if (fc_sof_needs_ack(fr_sof(fp)))
+		fr_eof(fp) = FC_EOF_N;
+
+	(void) lp->tt.frame_send(lp, fp);
+}
+
+/*
+ * Handle an incoming ABTS.  This would be for target mode usually,
+ * but could be due to lost FCP transfer ready, confirm or RRQ.
+ * We always handle this as an exchange abort, ignoring the parameter.
+ */
+static void fc_exch_recv_abts(struct fc_exch *ep, struct fc_frame *rx_fp)
+{
+	struct fc_frame *fp;
+	struct fc_ba_acc *ap;
+	struct fc_frame_header *fh;
+	struct fc_seq *sp;
+
+	if (!ep)
+		goto reject;
+	spin_lock_bh(&ep->ex_lock);
+	if (ep->esb_stat & ESB_ST_COMPLETE) {
+		spin_unlock_bh(&ep->ex_lock);
+		goto reject;
+	}
+	if (!(ep->esb_stat & ESB_ST_REC_QUAL))
+		fc_exch_hold(ep);		/* hold for REC_QUAL */
+	ep->esb_stat |= ESB_ST_ABNORMAL | ESB_ST_REC_QUAL;
+	fc_exch_timer_set_locked(ep, ep->r_a_tov);
+
+	fp = fc_frame_alloc(ep->lp, sizeof(*ap));
+	if (!fp) {
+		spin_unlock_bh(&ep->ex_lock);
+		goto free;
+	}
+	fh = fc_frame_header_get(fp);
+	ap = fc_frame_payload_get(fp, sizeof(*ap));
+	memset(ap, 0, sizeof(*ap));
+	sp = &ep->seq;
+	ap->ba_high_seq_cnt = htons(0xffff);
+	if (sp->ssb_stat & SSB_ST_RESP) {
+		ap->ba_seq_id = sp->id;
+		ap->ba_seq_id_val = FC_BA_SEQ_ID_VAL;
+		ap->ba_high_seq_cnt = fh->fh_seq_cnt;
+		ap->ba_low_seq_cnt = htons(sp->cnt);
+	}
+	sp = fc_seq_start_next(sp);
+	spin_unlock_bh(&ep->ex_lock);
+	fc_seq_send_last(sp, fp, FC_RCTL_BA_ACC, FC_TYPE_BLS);
+	fc_frame_free(rx_fp);
+	return;
+
+reject:
+	fc_exch_send_ba_rjt(rx_fp, FC_BA_RJT_UNABLE, FC_BA_RJT_INV_XID);
+free:
+	fc_frame_free(rx_fp);
+}
+
+/*
+ * Handle receive where the other end is originating the sequence.
+ */
+static void fc_exch_recv_req(struct fc_lport *lp, struct fc_exch_mgr *mp,
+			     struct fc_frame *fp)
+{
+	struct fc_frame_header *fh = fc_frame_header_get(fp);
+	struct fc_seq *sp = NULL;
+	struct fc_exch *ep = NULL;
+	enum fc_sof sof;
+	enum fc_eof eof;
+	u32 f_ctl;
+	enum fc_pf_rjt_reason reject;
+
+	fr_seq(fp) = NULL;
+	reject = fc_seq_lookup_recip(mp, fp);
+	if (reject == FC_RJT_NONE) {
+		sp = fr_seq(fp);	/* sequence will be held */
+		ep = fc_seq_exch(sp);
+		sof = fr_sof(fp);
+		eof = fr_eof(fp);
+		f_ctl = ntoh24(fh->fh_f_ctl);
+		fc_seq_send_ack(sp, fp);
+
+		/*
+		 * Call the receive function.
+		 *
+		 * The receive function may allocate a new sequence
+		 * over the old one, so we shouldn't change the
+		 * sequence after this.
+		 *
+		 * The frame will be freed by the receive function.
+		 * If new exch resp handler is valid then call that
+		 * first.
+		 */
+		if (ep->resp)
+			ep->resp(sp, fp, ep->arg);
+		else
+			lp->tt.lport_recv(lp, sp, fp);
+		fc_exch_release(ep);	/* release from lookup */
+	} else {
+		FC_DEBUG_EXCH("exch/seq lookup failed: reject %x\n", reject);
+		fc_frame_free(fp);
+	}
+}
+
+/*
+ * Handle receive where the other end is originating the sequence in
+ * response to our exchange.
+ */
+static void fc_exch_recv_seq_resp(struct fc_exch_mgr *mp, struct fc_frame *fp)
+{
+	struct fc_frame_header *fh = fc_frame_header_get(fp);
+	struct fc_seq *sp;
+	struct fc_exch *ep;
+	enum fc_sof sof;
+	u32 f_ctl;
+	void (*resp)(struct fc_seq *, struct fc_frame *fp, void *arg);
+	void *ex_resp_arg;
+	int rc;
+
+	ep = fc_exch_find(mp, ntohs(fh->fh_ox_id));
+	if (!ep) {
+		atomic_inc(&mp->stats.xid_not_found);
+		goto out;
+	}
+	if (ep->rxid == FC_XID_UNKNOWN)
+		ep->rxid = ntohs(fh->fh_rx_id);
+	if (ep->sid != 0 && ep->sid != ntoh24(fh->fh_d_id)) {
+		atomic_inc(&mp->stats.xid_not_found);
+		goto rel;
+	}
+	if (ep->did != ntoh24(fh->fh_s_id) &&
+	    ep->did != FC_FID_FLOGI) {
+		atomic_inc(&mp->stats.xid_not_found);
+		goto rel;
+	}
+	sof = fr_sof(fp);
+	if (fc_sof_is_init(sof)) {
+		sp = fc_seq_start_next(&ep->seq);
+		sp->id = fh->fh_seq_id;
+		sp->ssb_stat |= SSB_ST_RESP;
+	} else {
+		sp = &ep->seq;
+		if (sp->id != fh->fh_seq_id) {
+			atomic_inc(&mp->stats.seq_not_found);
+			goto rel;
+		}
+	}
+	f_ctl = ntoh24(fh->fh_f_ctl);
+	fr_seq(fp) = sp;
+	if (f_ctl & FC_FC_SEQ_INIT)
+		ep->esb_stat |= ESB_ST_SEQ_INIT;
+
+	if (fc_sof_needs_ack(sof))
+		fc_seq_send_ack(sp, fp);
+	resp = ep->resp;
+	ex_resp_arg = ep->arg;
+
+	if (fh->fh_type != FC_TYPE_FCP && fr_eof(fp) == FC_EOF_T &&
+	    (f_ctl & (FC_FC_LAST_SEQ | FC_FC_END_SEQ)) ==
+	    (FC_FC_LAST_SEQ | FC_FC_END_SEQ)) {
+		spin_lock_bh(&ep->ex_lock);
+		rc = fc_exch_done_locked(ep);
+		WARN_ON(fc_seq_exch(sp) != ep);
+		spin_unlock_bh(&ep->ex_lock);
+		if (!rc)
+			fc_exch_mgr_delete_ep(ep);
+	}
+
+	/*
+	 * Call the receive function.
+	 * The sequence is held (has a refcnt) for us,
+	 * but not for the receive function.
+	 *
+	 * The receive function may allocate a new sequence
+	 * over the old one, so we shouldn't change the
+	 * sequence after this.
+	 *
+	 * The frame will be freed by the receive function.
+	 * If new exch resp handler is valid then call that
+	 * first.
+	 */
+	if (resp)
+		resp(sp, fp, ex_resp_arg);
+	else
+		fc_frame_free(fp);
+	fc_exch_release(ep);
+	return;
+rel:
+	fc_exch_release(ep);
+out:
+	fc_frame_free(fp);
+}
+
+/*
+ * Handle receive for a sequence where other end is responding to our sequence.
+ */
+static void fc_exch_recv_resp(struct fc_exch_mgr *mp, struct fc_frame *fp)
+{
+	struct fc_seq *sp;
+
+	sp = fc_seq_lookup_orig(mp, fp);	/* doesn't hold sequence */
+	if (!sp) {
+		atomic_inc(&mp->stats.xid_not_found);
+		FC_DEBUG_EXCH("seq lookup failed\n");
+	} else {
+		atomic_inc(&mp->stats.non_bls_resp);
+		FC_DEBUG_EXCH("non-BLS response to sequence");
+	}
+	fc_frame_free(fp);
+}
+
+/*
+ * Handle the response to an ABTS for exchange or sequence.
+ * This can be BA_ACC or BA_RJT.
+ */
+static void fc_exch_abts_resp(struct fc_exch *ep, struct fc_frame *fp)
+{
+	void (*resp)(struct fc_seq *, struct fc_frame *fp, void *arg);
+	void *ex_resp_arg;
+	struct fc_frame_header *fh;
+	struct fc_ba_acc *ap;
+	struct fc_seq *sp;
+	u16 low;
+	u16 high;
+	int rc = 1, has_rec = 0;
+
+	fh = fc_frame_header_get(fp);
+	FC_DEBUG_EXCH("exch: BLS rctl %x - %s\n",
+		      fh->fh_r_ctl, fc_exch_rctl_name(fh->fh_r_ctl));
+
+	if (cancel_delayed_work_sync(&ep->timeout_work))
+		fc_exch_release(ep);	/* release from pending timer hold */
+
+	spin_lock_bh(&ep->ex_lock);
+	switch (fh->fh_r_ctl) {
+	case FC_RCTL_BA_ACC:
+		ap = fc_frame_payload_get(fp, sizeof(*ap));
+		if (!ap)
+			break;
+
+		/*
+		 * Decide whether to establish a Recovery Qualifier.
+		 * We do this if there is a non-empty SEQ_CNT range and
+		 * SEQ_ID is the same as the one we aborted.
+		 */
+		low = ntohs(ap->ba_low_seq_cnt);
+		high = ntohs(ap->ba_high_seq_cnt);
+		if ((ep->esb_stat & ESB_ST_REC_QUAL) == 0 &&
+		    (ap->ba_seq_id_val != FC_BA_SEQ_ID_VAL ||
+		     ap->ba_seq_id == ep->seq_id) && low != high) {
+			ep->esb_stat |= ESB_ST_REC_QUAL;
+			fc_exch_hold(ep);  /* hold for recovery qualifier */
+			has_rec = 1;
+		}
+		break;
+	case FC_RCTL_BA_RJT:
+		break;
+	default:
+		break;
+	}
+
+	resp = ep->resp;
+	ex_resp_arg = ep->arg;
+
+	/* do we need to do some other checks here. Can we reuse more of
+	 * fc_exch_recv_seq_resp
+	 */
+	sp = &ep->seq;
+	/*
+	 * do we want to check END_SEQ as well as LAST_SEQ here?
+	 */
+	if (ep->fh_type != FC_TYPE_FCP &&
+	    ntoh24(fh->fh_f_ctl) & FC_FC_LAST_SEQ)
+		rc = fc_exch_done_locked(ep);
+	spin_unlock_bh(&ep->ex_lock);
+	if (!rc)
+		fc_exch_mgr_delete_ep(ep);
+
+	if (resp)
+		resp(sp, fp, ex_resp_arg);
+	else
+		fc_frame_free(fp);
+
+	if (has_rec)
+		fc_exch_timer_set(ep, ep->r_a_tov);
+
+}
+
+/*
+ * Receive BLS sequence.
+ * This is always a sequence initiated by the remote side.
+ * We may be either the originator or recipient of the exchange.
+ */
+static void fc_exch_recv_bls(struct fc_exch_mgr *mp, struct fc_frame *fp)
+{
+	struct fc_frame_header *fh;
+	struct fc_exch *ep;
+	u32 f_ctl;
+
+	fh = fc_frame_header_get(fp);
+	f_ctl = ntoh24(fh->fh_f_ctl);
+	fr_seq(fp) = NULL;
+
+	ep = fc_exch_find(mp, (f_ctl & FC_FC_EX_CTX) ?
+			  ntohs(fh->fh_ox_id) : ntohs(fh->fh_rx_id));
+	if (ep && (f_ctl & FC_FC_SEQ_INIT)) {
+		spin_lock_bh(&ep->ex_lock);
+		ep->esb_stat |= ESB_ST_SEQ_INIT;
+		spin_unlock_bh(&ep->ex_lock);
+	}
+	if (f_ctl & FC_FC_SEQ_CTX) {
+		/*
+		 * A response to a sequence we initiated.
+		 * This should only be ACKs for class 2 or F.
+		 */
+		switch (fh->fh_r_ctl) {
+		case FC_RCTL_ACK_1:
+		case FC_RCTL_ACK_0:
+			break;
+		default:
+			FC_DEBUG_EXCH("BLS rctl %x - %s received",
+				      fh->fh_r_ctl,
+				      fc_exch_rctl_name(fh->fh_r_ctl));
+			break;
+		}
+		fc_frame_free(fp);
+	} else {
+		switch (fh->fh_r_ctl) {
+		case FC_RCTL_BA_RJT:
+		case FC_RCTL_BA_ACC:
+			if (ep)
+				fc_exch_abts_resp(ep, fp);
+			else
+				fc_frame_free(fp);
+			break;
+		case FC_RCTL_BA_ABTS:
+			fc_exch_recv_abts(ep, fp);
+			break;
+		default:			/* ignore junk */
+			fc_frame_free(fp);
+			break;
+		}
+	}
+	if (ep)
+		fc_exch_release(ep);	/* release hold taken by fc_exch_find */
+}
+
+/*
+ * Accept sequence with LS_ACC.
+ * If this fails due to allocation or transmit congestion, assume the
+ * originator will repeat the sequence.
+ */
+static void fc_seq_ls_acc(struct fc_seq *req_sp)
+{
+	struct fc_seq *sp;
+	struct fc_els_ls_acc *acc;
+	struct fc_frame *fp;
+
+	sp = fc_seq_start_next(req_sp);
+	fp = fc_frame_alloc(fc_seq_exch(sp)->lp, sizeof(*acc));
+	if (fp) {
+		acc = fc_frame_payload_get(fp, sizeof(*acc));
+		memset(acc, 0, sizeof(*acc));
+		acc->la_cmd = ELS_LS_ACC;
+		fc_seq_send_last(sp, fp, FC_RCTL_ELS_REP, FC_TYPE_ELS);
+	}
+}
+
+/*
+ * Reject sequence with ELS LS_RJT.
+ * If this fails due to allocation or transmit congestion, assume the
+ * originator will repeat the sequence.
+ */
+static void fc_seq_ls_rjt(struct fc_seq *req_sp, enum fc_els_rjt_reason reason,
+			  enum fc_els_rjt_explan explan)
+{
+	struct fc_seq *sp;
+	struct fc_els_ls_rjt *rjt;
+	struct fc_frame *fp;
+
+	sp = fc_seq_start_next(req_sp);
+	fp = fc_frame_alloc(fc_seq_exch(sp)->lp, sizeof(*rjt));
+	if (fp) {
+		rjt = fc_frame_payload_get(fp, sizeof(*rjt));
+		memset(rjt, 0, sizeof(*rjt));
+		rjt->er_cmd = ELS_LS_RJT;
+		rjt->er_reason = reason;
+		rjt->er_explan = explan;
+		fc_seq_send_last(sp, fp, FC_RCTL_ELS_REP, FC_TYPE_ELS);
+	}
+}
+
+static void fc_exch_reset(struct fc_exch *ep)
+{
+	struct fc_seq *sp;
+	void (*resp)(struct fc_seq *, struct fc_frame *, void *);
+	void *arg;
+	int rc = 1;
+
+	spin_lock_bh(&ep->ex_lock);
+	ep->state |= FC_EX_RST_CLEANUP;
+	/*
+	 * we really want to call del_timer_sync, but cannot due
+	 * to the lport calling with the lport lock held (some resp
+	 * functions can also grab the lport lock which could cause
+	 * a deadlock).
+	 */
+	if (cancel_delayed_work(&ep->timeout_work))
+		atomic_dec(&ep->ex_refcnt);	/* drop hold for timer */
+	resp = ep->resp;
+	ep->resp = NULL;
+	if (ep->esb_stat & ESB_ST_REC_QUAL)
+		atomic_dec(&ep->ex_refcnt);	/* drop hold for rec_qual */
+	ep->esb_stat &= ~ESB_ST_REC_QUAL;
+	arg = ep->arg;
+	sp = &ep->seq;
+	rc = fc_exch_done_locked(ep);
+	spin_unlock_bh(&ep->ex_lock);
+	if (!rc)
+		fc_exch_mgr_delete_ep(ep);
+
+	if (resp)
+		resp(sp, ERR_PTR(-FC_EX_CLOSED), arg);
+}
+
+/*
+ * Reset an exchange manager, releasing all sequences and exchanges.
+ * If sid is non-zero, reset only exchanges we source from that FID.
+ * If did is non-zero, reset only exchanges destined to that FID.
+ */
+void fc_exch_mgr_reset(struct fc_exch_mgr *mp, u32 sid, u32 did)
+{
+	struct fc_exch *ep;
+	struct fc_exch *next;
+
+	spin_lock_bh(&mp->em_lock);
+restart:
+	list_for_each_entry_safe(ep, next, &mp->ex_list, ex_list) {
+		if ((sid == 0 || sid == ep->sid) &&
+		    (did == 0 || did == ep->did)) {
+			fc_exch_hold(ep);
+			spin_unlock_bh(&mp->em_lock);
+
+			fc_exch_reset(ep);
+
+			fc_exch_release(ep);
+			spin_lock_bh(&mp->em_lock);
+
+			/*
+			 * must restart loop incase while lock was down
+			 * multiple eps were released.
+			 */
+			goto restart;
+		}
+	}
+	spin_unlock_bh(&mp->em_lock);
+}
+EXPORT_SYMBOL(fc_exch_mgr_reset);
+
+/*
+ * Handle incoming ELS REC - Read Exchange Concise.
+ * Note that the requesting port may be different than the S_ID in the request.
+ */
+static void fc_exch_els_rec(struct fc_seq *sp, struct fc_frame *rfp)
+{
+	struct fc_frame *fp;
+	struct fc_exch *ep;
+	struct fc_exch_mgr *em;
+	struct fc_els_rec *rp;
+	struct fc_els_rec_acc *acc;
+	enum fc_els_rjt_reason reason = ELS_RJT_LOGIC;
+	enum fc_els_rjt_explan explan;
+	u32 sid;
+	u16 rxid;
+	u16 oxid;
+
+	rp = fc_frame_payload_get(rfp, sizeof(*rp));
+	explan = ELS_EXPL_INV_LEN;
+	if (!rp)
+		goto reject;
+	sid = ntoh24(rp->rec_s_id);
+	rxid = ntohs(rp->rec_rx_id);
+	oxid = ntohs(rp->rec_ox_id);
+
+	/*
+	 * Currently it's hard to find the local S_ID from the exchange
+	 * manager.  This will eventually be fixed, but for now it's easier
+	 * to lookup the subject exchange twice, once as if we were
+	 * the initiator, and then again if we weren't.
+	 */
+	em = fc_seq_exch(sp)->em;
+	ep = fc_exch_find(em, oxid);
+	explan = ELS_EXPL_OXID_RXID;
+	if (ep && ep->oid == sid) {
+		if (ep->rxid != FC_XID_UNKNOWN &&
+		    rxid != FC_XID_UNKNOWN &&
+		    ep->rxid != rxid)
+			goto rel;
+	} else {
+		if (ep)
+			fc_exch_release(ep);
+		ep = NULL;
+		if (rxid != FC_XID_UNKNOWN)
+			ep = fc_exch_find(em, rxid);
+		if (!ep)
+			goto reject;
+	}
+
+	fp = fc_frame_alloc(fc_seq_exch(sp)->lp, sizeof(*acc));
+	if (!fp) {
+		fc_exch_done(sp);
+		goto out;
+	}
+	sp = fc_seq_start_next(sp);
+	acc = fc_frame_payload_get(fp, sizeof(*acc));
+	memset(acc, 0, sizeof(*acc));
+	acc->reca_cmd = ELS_LS_ACC;
+	acc->reca_ox_id = rp->rec_ox_id;
+	memcpy(acc->reca_ofid, rp->rec_s_id, 3);
+	acc->reca_rx_id = htons(ep->rxid);
+	if (ep->sid == ep->oid)
+		hton24(acc->reca_rfid, ep->did);
+	else
+		hton24(acc->reca_rfid, ep->sid);
+	acc->reca_fc4value = htonl(ep->seq.rec_data);
+	acc->reca_e_stat = htonl(ep->esb_stat & (ESB_ST_RESP |
+						 ESB_ST_SEQ_INIT |
+						 ESB_ST_COMPLETE));
+	sp = fc_seq_start_next(sp);
+	fc_seq_send_last(sp, fp, FC_RCTL_ELS_REP, FC_TYPE_ELS);
+out:
+	fc_exch_release(ep);
+	fc_frame_free(rfp);
+	return;
+
+rel:
+	fc_exch_release(ep);
+reject:
+	fc_seq_ls_rjt(sp, reason, explan);
+	fc_frame_free(rfp);
+}
+
+/*
+ * Handle response from RRQ.
+ * Not much to do here, really.
+ * Should report errors.
+ *
+ * TODO: fix error handler.
+ */
+static void fc_exch_rrq_resp(struct fc_seq *sp, struct fc_frame *fp, void *arg)
+{
+	struct fc_exch *aborted_ep = arg;
+	unsigned int op;
+
+	if (IS_ERR(fp)) {
+		int err = PTR_ERR(fp);
+
+		if (err == -FC_EX_CLOSED)
+			goto cleanup;
+		FC_DBG("Cannot process RRQ, because of frame error %d\n", err);
+		return;
+	}
+
+	op = fc_frame_payload_op(fp);
+	fc_frame_free(fp);
+
+	switch (op) {
+	case ELS_LS_RJT:
+		FC_DBG("LS_RJT for RRQ");
+		/* fall through */
+	case ELS_LS_ACC:
+		goto cleanup;
+	default:
+		FC_DBG("unexpected response op %x for RRQ", op);
+		return;
+	}
+
+cleanup:
+	fc_exch_done(&aborted_ep->seq);
+	/* drop hold for rec qual */
+	fc_exch_release(aborted_ep);
+}
+
+/*
+ * Send ELS RRQ - Reinstate Recovery Qualifier.
+ * This tells the remote port to stop blocking the use of
+ * the exchange and the seq_cnt range.
+ */
+static void fc_exch_rrq(struct fc_exch *ep)
+{
+	struct fc_lport *lp;
+	struct fc_els_rrq *rrq;
+	struct fc_frame *fp;
+	struct fc_seq *rrq_sp;
+	u32 did;
+
+	lp = ep->lp;
+
+	fp = fc_frame_alloc(lp, sizeof(*rrq));
+	if (!fp)
+		return;
+	rrq = fc_frame_payload_get(fp, sizeof(*rrq));
+	memset(rrq, 0, sizeof(*rrq));
+	rrq->rrq_cmd = ELS_RRQ;
+	hton24(rrq->rrq_s_id, ep->sid);
+	rrq->rrq_ox_id = htons(ep->oxid);
+	rrq->rrq_rx_id = htons(ep->rxid);
+
+	did = ep->did;
+	if (ep->esb_stat & ESB_ST_RESP)
+		did = ep->sid;
+
+	fc_fill_fc_hdr(fp, FC_RCTL_ELS_REQ, did,
+		       fc_host_port_id(lp->host), FC_TYPE_ELS,
+		       FC_FC_FIRST_SEQ | FC_FC_END_SEQ | FC_FC_SEQ_INIT, 0);
+
+	rrq_sp = fc_exch_seq_send(lp, fp, fc_exch_rrq_resp, NULL, ep,
+				  lp->e_d_tov);
+	if (!rrq_sp) {
+		ep->esb_stat |= ESB_ST_REC_QUAL;
+		fc_exch_timer_set_locked(ep, ep->r_a_tov);
+		return;
+	}
+}
+
+
+/*
+ * Handle incoming ELS RRQ - Reset Recovery Qualifier.
+ */
+static void fc_exch_els_rrq(struct fc_seq *sp, struct fc_frame *fp)
+{
+	struct fc_exch *ep;		/* request or subject exchange */
+	struct fc_els_rrq *rp;
+	u32 sid;
+	u16 xid;
+	enum fc_els_rjt_explan explan;
+
+	rp = fc_frame_payload_get(fp, sizeof(*rp));
+	explan = ELS_EXPL_INV_LEN;
+	if (!rp)
+		goto reject;
+
+	/*
+	 * lookup subject exchange.
+	 */
+	ep = fc_seq_exch(sp);
+	sid = ntoh24(rp->rrq_s_id);		/* subject source */
+	xid = ep->did == sid ? ntohs(rp->rrq_ox_id) : ntohs(rp->rrq_rx_id);
+	ep = fc_exch_find(ep->em, xid);
+
+	explan = ELS_EXPL_OXID_RXID;
+	if (!ep)
+		goto reject;
+	spin_lock_bh(&ep->ex_lock);
+	if (ep->oxid != ntohs(rp->rrq_ox_id))
+		goto unlock_reject;
+	if (ep->rxid != ntohs(rp->rrq_rx_id) &&
+	    ep->rxid != FC_XID_UNKNOWN)
+		goto unlock_reject;
+	explan = ELS_EXPL_SID;
+	if (ep->sid != sid)
+		goto unlock_reject;
+
+	/*
+	 * Clear Recovery Qualifier state, and cancel timer if complete.
+	 */
+	if (ep->esb_stat & ESB_ST_REC_QUAL) {
+		ep->esb_stat &= ~ESB_ST_REC_QUAL;
+		atomic_dec(&ep->ex_refcnt);	/* drop hold for rec qual */
+	}
+	if (ep->esb_stat & ESB_ST_COMPLETE) {
+		if (cancel_delayed_work(&ep->timeout_work))
+			atomic_dec(&ep->ex_refcnt);	/* drop timer hold */
+	}
+
+	spin_unlock_bh(&ep->ex_lock);
+
+	/*
+	 * Send LS_ACC.
+	 */
+	fc_seq_ls_acc(sp);
+	fc_frame_free(fp);
+	return;
+
+unlock_reject:
+	spin_unlock_bh(&ep->ex_lock);
+	fc_exch_release(ep);	/* drop hold from fc_exch_find */
+reject:
+	fc_seq_ls_rjt(sp, ELS_RJT_LOGIC, explan);
+	fc_frame_free(fp);
+}
+
+struct fc_exch_mgr *fc_exch_mgr_alloc(struct fc_lport *lp,
+				      enum fc_class class,
+				      u16 min_xid, u16 max_xid)
+{
+	struct fc_exch_mgr *mp;
+	size_t len;
+
+	if (max_xid <= min_xid || min_xid == 0 || max_xid == FC_XID_UNKNOWN) {
+		FC_DBG("Invalid min_xid 0x:%x and max_xid 0x:%x\n",
+		       min_xid, max_xid);
+		return NULL;
+	}
+
+	/*
+	 * Memory need for EM
+	 */
+#define xid_ok(i, m1, m2) (((i) >= (m1)) && ((i) <= (m2)))
+	len = (max_xid - min_xid + 1) * (sizeof(struct fc_exch *));
+	len += sizeof(struct fc_exch_mgr);
+
+	mp = kzalloc(len, GFP_ATOMIC);
+	if (!mp)
+		return NULL;
+
+	mp->class = class;
+	mp->total_exches = 0;
+	mp->exches = (struct fc_exch **)(mp + 1);
+	mp->lp = lp;
+	/* adjust em exch xid range for offload */
+	mp->min_xid = min_xid;
+	mp->max_xid = max_xid;
+	mp->last_xid = min_xid - 1;
+	mp->max_read = 0;
+	mp->last_read = 0;
+	if (lp->lro_enabled && xid_ok(lp->lro_xid, min_xid, max_xid)) {
+		mp->max_read = lp->lro_xid;
+		mp->last_read = min_xid - 1;
+		mp->last_xid = mp->max_read;
+	} else {
+		/* disable lro if no xid control over read */
+		lp->lro_enabled = 0;
+	}
+
+	INIT_LIST_HEAD(&mp->ex_list);
+	spin_lock_init(&mp->em_lock);
+
+	mp->ep_pool = mempool_create_slab_pool(2, fc_em_cachep);
+	if (!mp->ep_pool)
+		goto free_mp;
+
+	return mp;
+
+free_mp:
+	kfree(mp);
+	return NULL;
+}
+EXPORT_SYMBOL(fc_exch_mgr_alloc);
+
+void fc_exch_mgr_free(struct fc_exch_mgr *mp)
+{
+	WARN_ON(!mp);
+	/*
+	 * The total exch count must be zero
+	 * before freeing exchange manager.
+	 */
+	WARN_ON(mp->total_exches != 0);
+	mempool_destroy(mp->ep_pool);
+	kfree(mp);
+}
+EXPORT_SYMBOL(fc_exch_mgr_free);
+
+struct fc_exch *fc_exch_get(struct fc_lport *lp, struct fc_frame *fp)
+{
+	if (!lp || !lp->emp)
+		return NULL;
+
+	return fc_exch_alloc(lp->emp, fp, 0);
+}
+EXPORT_SYMBOL(fc_exch_get);
+
+struct fc_seq *fc_exch_seq_send(struct fc_lport *lp,
+				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)
+{
+	struct fc_exch *ep;
+	struct fc_seq *sp = NULL;
+	struct fc_frame_header *fh;
+	int rc = 1;
+
+	ep = lp->tt.exch_get(lp, fp);
+	if (!ep) {
+		fc_frame_free(fp);
+		return NULL;
+	}
+	ep->esb_stat |= ESB_ST_SEQ_INIT;
+	fh = fc_frame_header_get(fp);
+	fc_exch_set_addr(ep, ntoh24(fh->fh_s_id), ntoh24(fh->fh_d_id));
+	ep->resp = resp;
+	ep->destructor = destructor;
+	ep->arg = arg;
+	ep->r_a_tov = FC_DEF_R_A_TOV;
+	ep->lp = lp;
+	sp = &ep->seq;
+
+	ep->fh_type = fh->fh_type; /* save for possbile timeout handling */
+	ep->f_ctl = ntoh24(fh->fh_f_ctl);
+	fc_exch_setup_hdr(ep, fp, ep->f_ctl);
+	sp->cnt++;
+
+	if (unlikely(lp->tt.frame_send(lp, fp)))
+		goto err;
+
+	if (timer_msec)
+		fc_exch_timer_set_locked(ep, timer_msec);
+	ep->f_ctl &= ~FC_FC_FIRST_SEQ;	/* not first seq */
+
+	if (ep->f_ctl & FC_FC_SEQ_INIT)
+		ep->esb_stat &= ~ESB_ST_SEQ_INIT;
+	spin_unlock_bh(&ep->ex_lock);
+	return sp;
+err:
+	rc = fc_exch_done_locked(ep);
+	spin_unlock_bh(&ep->ex_lock);
+	if (!rc)
+		fc_exch_mgr_delete_ep(ep);
+	return NULL;
+}
+EXPORT_SYMBOL(fc_exch_seq_send);
+
+/*
+ * Receive a frame
+ */
+void fc_exch_recv(struct fc_lport *lp, struct fc_exch_mgr *mp,
+		  struct fc_frame *fp)
+{
+	struct fc_frame_header *fh = fc_frame_header_get(fp);
+	u32 f_ctl;
+
+	/* lport lock ? */
+	if (!lp || !mp || (lp->state == LPORT_ST_NONE)) {
+		FC_DBG("fc_lport or EM is not allocated and configured");
+		fc_frame_free(fp);
+		return;
+	}
+
+	/*
+	 * If frame is marked invalid, just drop it.
+	 */
+	f_ctl = ntoh24(fh->fh_f_ctl);
+	switch (fr_eof(fp)) {
+	case FC_EOF_T:
+		if (f_ctl & FC_FC_END_SEQ)
+			skb_trim(fp_skb(fp), fr_len(fp) - FC_FC_FILL(f_ctl));
+		/* fall through */
+	case FC_EOF_N:
+		if (fh->fh_type == FC_TYPE_BLS)
+			fc_exch_recv_bls(mp, fp);
+		else if ((f_ctl & (FC_FC_EX_CTX | FC_FC_SEQ_CTX)) ==
+			 FC_FC_EX_CTX)
+			fc_exch_recv_seq_resp(mp, fp);
+		else if (f_ctl & FC_FC_SEQ_CTX)
+			fc_exch_recv_resp(mp, fp);
+		else
+			fc_exch_recv_req(lp, mp, fp);
+		break;
+	default:
+		FC_DBG("dropping invalid frame (eof %x)", fr_eof(fp));
+		fc_frame_free(fp);
+		break;
+	}
+}
+EXPORT_SYMBOL(fc_exch_recv);
+
+int fc_exch_init(struct fc_lport *lp)
+{
+	if (!lp->tt.exch_get) {
+		/*
+		 *  exch_put() should be NULL if
+		 *  exch_get() is NULL
+		 */
+		WARN_ON(lp->tt.exch_put);
+		lp->tt.exch_get = fc_exch_get;
+	}
+
+	if (!lp->tt.seq_start_next)
+		lp->tt.seq_start_next = fc_seq_start_next;
+
+	if (!lp->tt.exch_seq_send)
+		lp->tt.exch_seq_send = fc_exch_seq_send;
+
+	if (!lp->tt.seq_send)
+		lp->tt.seq_send = fc_seq_send;
+
+	if (!lp->tt.seq_els_rsp_send)
+		lp->tt.seq_els_rsp_send = fc_seq_els_rsp_send;
+
+	if (!lp->tt.exch_done)
+		lp->tt.exch_done = fc_exch_done;
+
+	if (!lp->tt.exch_mgr_reset)
+		lp->tt.exch_mgr_reset = fc_exch_mgr_reset;
+
+	if (!lp->tt.seq_exch_abort)
+		lp->tt.seq_exch_abort = fc_seq_exch_abort;
+
+	return 0;
+}
+EXPORT_SYMBOL(fc_exch_init);
+
+int fc_setup_exch_mgr(void)
+{
+	fc_em_cachep = kmem_cache_create("libfc_em", sizeof(struct fc_exch),
+					 0, SLAB_HWCACHE_ALIGN, NULL);
+	if (!fc_em_cachep)
+		return -ENOMEM;
+	return 0;
+}
+
+void fc_destroy_exch_mgr(void)
+{
+	kmem_cache_destroy(fc_em_cachep);
+}