[SCSI] fcoe, fnic, libfc: modifies current code paths to use EM anchor list

Modifies current code to use EM anchor list in EM allocation, EM free,
EM reset, exch allocation and exch lookup code paths.

 1. Modifies fc_exch_mgr_alloc to accept EM match function and then
    have allocated EM added to the lport using fc_exch_mgr_add API
    while also updating EM kref for newly added EM.

 2. Updates fc_exch_mgr_free API to accept only lport pointer instead
    EM and then have this API free all EMs of the lport from EM anchor
    list.

 3. Removes single lport pointer link from the EM, which was used in
    associating lport pointer in newly allocated exchange. Instead have
    lport pointer passed along new exchange allocation call path and
    then store passed lport pointer in newly allocated exchange, this
    will allow a single EM instance to be used across more than one
    lport and used in EM reset to reset only lport specific exchanges.

 4. Modifies fc_exch_mgr_reset to reset all EMs from the EM anchor list
    of the lport, adds additional exch lport pointer (ep->lp) check for
    shared EM case to reset exchange specific to a lport requested reset.

 5. Updates exch allocation API fc_exch_alloc to use EM anchor list and
    its anchor match func pointer. The fc_exch_alloc will walk the list
    of EMs until it finds a match, a match will be either null match
    func pointer or call to match function returning true value.

 6. Updates fc_exch_recv to accept incoming frame on local port using
    only lport pointer and frame pointer without specifying EM instance
    of incoming frame. Instead modified fc_exch_recv to locate EM for the
    incoming frame by matching xid of incoming frame against a EM xid range.
    This change was required to use EM list in libfc Rx path and after this
    change the lport fc_exch_mgr pointer emp is not needed anymore, so
    removed emp pointer.

 7. Updates fnic for removed lport emp pointer and above modified libfc APIs
    fc_exch_recv, fc_exch_mgr_alloc and fc_exch_mgr_free.

 8. Removes exch_get and exch_put from libfc_function_template as these
    are no longer needed with EM anchor list and its match function use.
    Also removes its default function fc_exch_get.

A defect this patch introduced regarding the libfc initialization order in
the fnic driver was fixed by Joe Eykholt <jeykholt@cisco.com>.

Signed-off-by: Vasu Dev <vasu.dev@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

2 files changed, 7 insertions, 11 deletions

diff --git a/drivers/scsi/fcoe/fcoe.c b/drivers/scsi/fcoe/fcoe.c
index 719a99d4a438..ebf2e20370d7 100644
--- a/drivers/scsi/fcoe/fcoe.c
+++ b/drivers/scsi/fcoe/fcoe.c
@@ -423,11 +423,8 @@ static int fcoe_shost_config(struct fc_lport *lp, struct Scsi_Host *shost,
  */
 static inline int fcoe_em_config(struct fc_lport *lp)
 {
-	BUG_ON(lp->emp);
-
-	lp->emp = fc_exch_mgr_alloc(lp, FC_CLASS_3,
-				    FCOE_MIN_XID, FCOE_MAX_XID);
-	if (!lp->emp)
+	if (!fc_exch_mgr_alloc(lp, FC_CLASS_3, FCOE_MIN_XID,
+			       FCOE_MAX_XID, NULL))
 		return -ENOMEM;
 
 	return 0;
@@ -478,8 +475,7 @@ static int fcoe_if_destroy(struct net_device *netdev)
 	scsi_remove_host(lp->host);
 
 	/* There are no more rports or I/O, free the EM */
-	if (lp->emp)
-		fc_exch_mgr_free(lp->emp);
+	fc_exch_mgr_free(lp);
 
 	/* Free existing skbs */
 	fcoe_clean_pending_queue(lp);
@@ -634,7 +630,7 @@ static int fcoe_if_create(struct net_device *netdev)
 	return rc;
 
 out_lp_destroy:
-	fc_exch_mgr_free(lp->emp); /* Free the EM */
+	fc_exch_mgr_free(lp);
 out_netdev_cleanup:
 	fcoe_netdev_cleanup(fc);
 out_host_put:
@@ -1277,7 +1273,7 @@ int fcoe_percpu_receive_thread(void *arg)
 		fh = fc_frame_header_get(fp);
 		if (fh->fh_r_ctl == FC_RCTL_DD_SOL_DATA &&
 		    fh->fh_type == FC_TYPE_FCP) {
-			fc_exch_recv(lp, lp->emp, fp);
+			fc_exch_recv(lp, fp);
 			continue;
 		}
 		if (fr_flags(fp) & FCPHF_CRC_UNCHECKED) {
@@ -1298,7 +1294,7 @@ int fcoe_percpu_receive_thread(void *arg)
 			fc_frame_free(fp);
 			continue;
 		}
-		fc_exch_recv(lp, lp->emp, fp);
+		fc_exch_recv(lp, fp);
 	}
 	return 0;
 }
diff --git a/drivers/scsi/fcoe/libfcoe.c b/drivers/scsi/fcoe/libfcoe.c
index 78caa6be1130..4db719d6ada1 100644
--- a/drivers/scsi/fcoe/libfcoe.c
+++ b/drivers/scsi/fcoe/libfcoe.c
@@ -885,7 +885,7 @@ static void fcoe_ctlr_recv_els(struct fcoe_ctlr *fip, struct sk_buff *skb)
 	stats->RxFrames++;
 	stats->RxWords += skb->len / FIP_BPW;
 
-	fc_exch_recv(lp, lp->emp, fp);
+	fc_exch_recv(lp, fp);
 	return;
 
 len_err: