[SCSI] libfc: Fix frags in frame exceeding SKB_MAX_FRAGS in fc_fcp_send_data

In case of sequence offload, in fc_fcp_send_data(), the skb_fill_page_info()
called may end up adding more frags to the skb_shinfo(fp_skb(fp))->frags[],
exceeding SKB_MAX_FRAGS, this eventually corrupts the memory. I am adding the
FR_FRAME_SG_LEN back, but as SKB_MAX_FRAGS -1, leaving 1 for our fcoe_eof_crc
page. And send will be broken into multiple large sends if the frame already
contains more frags than skb handle.

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>

drivers/scsi/libfc/fc_fcp.c

@@ -574,7 +574,8 @@ static int fc_fcp_send_data(struct fc_fcp_pkt *fsp, struct fc_seq *seq,
 		tlen -= sg_bytes;
 		remaining -= sg_bytes;
 
-		if (tlen)
+		if ((skb_shinfo(fp_skb(fp))->nr_frags < FC_FRAME_SG_LEN) &&
+		    (tlen))
 			continue;
 
 		/*