[SCSI] libfcoe: add checking disable flag in FIP_FKA_ADV

When the D bit is set if the FKA_ADV_Period of the FIP Discovery
Advertisement, the ENode should not transmit period ENode FIP Keep Alive and
VN_Port FIP Keep Alive (FC-BB-5 Rev2, 7.8.3.13).

Note that fcf->flags is taken directly from the fip_header, I am claiming one
bit for the purpose of the FIP_FKA_Period D bit as FIP_FL_FK_ADV_B, and use
FIP_HEADER_FLAGS as bitmask for bits used in fip_header.

Signed-off-by: Yi Zou <yi.zou@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
diff --git a/drivers/scsi/fcoe/libfcoe.c b/drivers/scsi/fcoe/libfcoe.c
index 3c501d4..9961fd7 100644
--- a/drivers/scsi/fcoe/libfcoe.c
+++ b/drivers/scsi/fcoe/libfcoe.c
@@ -665,6 +665,8 @@
 			if (dlen != sizeof(struct fip_fka_desc))
 				goto len_err;
 			fka = (struct fip_fka_desc *)desc;
+			if (fka->fd_flags & FIP_FKA_ADV_D)
+				fcf->fd_flags = 1;
 			t = ntohl(fka->fd_fka_period);
 			if (t >= FCOE_CTLR_MIN_FKA)
 				fcf->fka_period = msecs_to_jiffies(t);
@@ -1160,7 +1162,7 @@
 		}
 	}
 
-	if (sel) {
+	if (sel && !sel->fd_flags) {
 		if (time_after_eq(jiffies, fip->ctlr_ka_time)) {
 			fip->ctlr_ka_time = jiffies + sel->fka_period;
 			fip->send_ctlr_ka = 1;