[SCSI] libfc: export seq_release() for users of seq_assign()

Target modules using lport->tt.seq_assign() get a hold on the
exchange but have no way of releasing it.  Add that.
Signed-off-by: NJoe Eykholt <jeykholt@cisco.com>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>

drivers/scsi/libfc/fc_exch.c

@@ -1282,6 +1282,8 @@ static void fc_exch_recv_abts(struct fc_exch *ep, struct fc_frame *rx_fp)
  * @fp:    The request frame
  *
  * On success, the sequence pointer will be returned and also in fr_seq(@fp).
+ * A reference will be held on the exchange/sequence for the caller, which
+ * must call fc_seq_release().
  */
 static struct fc_seq *fc_seq_assign(struct fc_lport *lport, struct fc_frame *fp)
 {
@@ -1298,6 +1300,15 @@ static struct fc_seq *fc_seq_assign(struct fc_lport *lport, struct fc_frame *fp)
 	return fr_seq(fp);
 }
 
+/**
+ * fc_seq_release() - Release the hold
+ * @sp:    The sequence.
+ */
+static void fc_seq_release(struct fc_seq *sp)
+{
+	fc_exch_release(fc_seq_exch(sp));
+}
+
 /**
  * fc_exch_recv_req() - Handler for an incoming request
  * @lport: The local port that received the request
@@ -2369,6 +2380,9 @@ int fc_exch_init(struct fc_lport *lport)
 	if (!lport->tt.seq_assign)
 		lport->tt.seq_assign = fc_seq_assign;
 
+	if (!lport->tt.seq_release)
+		lport->tt.seq_release = fc_seq_release;
+
 	return 0;
 }
 EXPORT_SYMBOL(fc_exch_init);

include/scsi/libfc.h

@@ -571,6 +571,13 @@ struct libfc_function_template {
 	 */
 	struct fc_seq *(*seq_assign)(struct fc_lport *, struct fc_frame *);
 
+	/*
+	 * Release the reference on the sequence returned by seq_assign().
+	 *
+	 * STATUS: OPTIONAL
+	 */
+	void (*seq_release)(struct fc_seq *);
+
 	/*
 	 * Reset an exchange manager, completing all sequences and exchanges.
 	 * If s_id is non-zero, reset only exchanges originating from that FID.