[SCSI] libfc: provide space for LLD after remote port structure

Add pre-zeroed space after the allocation for fc_rport_priv
for use by the lower-level driver.

This is primarily for VN2VN FIP mode, but could be used in
other ways someday.

The space required is specified in lport->rport_priv_size.
Signed-off-by: Joe Eykholt <jeykholt@cisco.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

drivers/scsi/libfc/fc_rport.c

@@ -127,7 +127,7 @@ static struct fc_rport_priv *fc_rport_create(struct fc_lport *lport,
 	if (rdata)
 		return rdata;
 
-	rdata = kzalloc(sizeof(*rdata), GFP_KERNEL);
+	rdata = kzalloc(sizeof(*rdata) + lport->rport_priv_size, GFP_KERNEL);
 	if (!rdata)
 		return NULL;
 

include/scsi/libfc.h

@@ -799,6 +799,7 @@ struct fc_disc {
  * @mfs:                   The maximum Fibre Channel payload size
  * @max_retry_count:       The maximum retry attempts
  * @max_rport_retry_count: The maximum remote port retry attempts
+ * @rport_priv_size:       Size needed by driver after struct fc_rport_priv
  * @lro_xid:               The maximum XID for LRO
  * @lso_max:               The maximum large offload send size
  * @fcts:                  FC-4 type mask
@@ -848,6 +849,7 @@ struct fc_lport {
 	u32			       mfs;
 	u8			       max_retry_count;
 	u8			       max_rport_retry_count;
+	u16			       rport_priv_size;
 	u16			       link_speed;
 	u16			       link_supported_speeds;
 	u16			       lro_xid;