[SCSI] libfc: update fc_host mfs along with updating lport->mfs

Currently fc_host mfs is not getting updated in
case its changed during FLOGI and that leaves fc_host
to show its initial old value in sysfs, so instead
have fc_host mfs updated along with updating lport mfs
during FLOGI.

Also in case of bad mfs during flogi, error out
instead of continuing with flogi.

[ Changes made by Robert Love: condition to '>=' and
  added printing of lport->mfs in DBG statement. FLOGI
  resp processing failed without being able to compare
  FCoE MFS 2112 against an incoming MFS of 2112 ]

Signed-off-by: Vasu Dev <vasu.dev@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/libfc/fc_lport.c

@@ -1743,8 +1743,16 @@ void fc_lport_flogi_resp(struct fc_seq *sp, struct fc_frame *fp,
 	mfs = ntohs(flp->fl_csp.sp_bb_data) &
 		FC_SP_BB_DATA_MASK;
 	if (mfs >= FC_SP_MIN_MAX_PAYLOAD &&
-	    mfs < lport->mfs)
+	    mfs <= lport->mfs) {
 		lport->mfs = mfs;
+		fc_host_maxframe_size(lport->host) = mfs;
+	} else {
+		FC_LPORT_DBG(lport, "FLOGI bad mfs:%hu response, "
+			     "lport->mfs:%hu\n", mfs, lport->mfs);
+		fc_lport_error(lport, fp);
+		goto err;
+	}
+
 	csp_flags = ntohs(flp->fl_csp.sp_features);
 	r_a_tov = ntohl(flp->fl_csp.sp_r_a_tov);
 	e_d_tov = ntohl(flp->fl_csp.sp_e_d_tov);