[PATCH v2] net: tftp: Avoid sending extra ack on completion

[Ramon Fried <rfried.dev@gmail.com>]

in tftpboot, if ack was already sent previously for this
packet, don't send again.

Fixes: cc6b87ecaa96 ("net: tftp: Add client support for RFC 7440")

Reported-by: Suneel Garapati <suneelglinux@gmail.com>
Signed-off-by: Ramon Fried <rfried.dev@gmail.com>
---
v2: Fix it so it actually works :)

 net/tftp.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/net/tftp.c b/net/tftp.c
index 03079ded34..6b781ccf67 100644
--- a/net/tftp.c
+++ b/net/tftp.c
@@ -668,6 +668,12 @@ static void tftp_handler(uchar *pkt, unsigned dest, struct in_addr sip,
 			break;
 		}
 
+		if (len < tftp_block_size) {
+			tftp_send();
+			tftp_complete();
+			break;
+		}
+
 		/*
 		 *	Acknowledge the block just received, which will prompt
 		 *	the remote for the next one.
@@ -676,11 +682,6 @@ static void tftp_handler(uchar *pkt, unsigned dest, struct in_addr sip,
 			tftp_send();
 			tftp_next_ack += tftp_windowsize;
 		}
-
-		if (len < tftp_block_size) {
-			tftp_send();
-			tftp_complete();
-		}
 		break;
 
 	case TFTP_ERROR:
-- 
2.17.1