From f8e98486564494f075d49d33229aa81fb7da013d Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@google.com>
Date: Tue, 27 Jun 2023 12:10:13 +0000
Subject: [PATCH] Revert "tipc: add tipc_bearer_min_mtu to calculate min mtu"

This reverts commit 097ea78d8ccaf789eeeb154fdfb6afbd274a2a87 which is
commit 3ae6d66b605be604644d4bb5708a7ffd9cf1abe8 upstream.

It breaks the Android kernel ABI and is not needed for Android devices,
so it is safe to revert for now.  If it is determined that it is needed
in the future, it can be brought back in an abi-preserving way.

Bug: 161946584
Change-Id: I0b32b3b8d7c81895dd1680f7aec65d38cace080d
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
---
 net/tipc/bearer.c    | 13 -------------
 net/tipc/bearer.h    |  3 ---
 net/tipc/udp_media.c |  5 ++---
 3 files changed, 2 insertions(+), 19 deletions(-)

diff --git a/net/tipc/bearer.c b/net/tipc/bearer.c
index c6a9b3446ff8..72c31ef985eb 100644
--- a/net/tipc/bearer.c
+++ b/net/tipc/bearer.c
@@ -525,19 +525,6 @@ int tipc_bearer_mtu(struct net *net, u32 bearer_id)
 	return mtu;
 }
 
-int tipc_bearer_min_mtu(struct net *net, u32 bearer_id)
-{
-	int mtu = TIPC_MIN_BEARER_MTU;
-	struct tipc_bearer *b;
-
-	rcu_read_lock();
-	b = bearer_get(net, bearer_id);
-	if (b)
-		mtu += b->encap_hlen;
-	rcu_read_unlock();
-	return mtu;
-}
-
 /* tipc_bearer_xmit_skb - sends buffer to destination over bearer
  */
 void tipc_bearer_xmit_skb(struct net *net, u32 bearer_id,
diff --git a/net/tipc/bearer.h b/net/tipc/bearer.h
index 711a50f44993..6bf4550aa1ac 100644
--- a/net/tipc/bearer.h
+++ b/net/tipc/bearer.h
@@ -146,7 +146,6 @@ struct tipc_media {
  * @identity: array index of this bearer within TIPC bearer array
  * @disc: ptr to link setup request
  * @net_plane: network plane ('A' through 'H') currently associated with bearer
- * @encap_hlen: encap headers length
  * @up: bearer up flag (bit 0)
  * @refcnt: tipc_bearer reference counter
  *
@@ -171,7 +170,6 @@ struct tipc_bearer {
 	u32 identity;
 	struct tipc_discoverer *disc;
 	char net_plane;
-	u16 encap_hlen;
 	unsigned long up;
 	refcount_t refcnt;
 };
@@ -234,7 +232,6 @@ int tipc_bearer_setup(void);
 void tipc_bearer_cleanup(void);
 void tipc_bearer_stop(struct net *net);
 int tipc_bearer_mtu(struct net *net, u32 bearer_id);
-int tipc_bearer_min_mtu(struct net *net, u32 bearer_id);
 bool tipc_bearer_bcast_support(struct net *net, u32 bearer_id);
 void tipc_bearer_xmit_skb(struct net *net, u32 bearer_id,
 			  struct sk_buff *skb,
diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c
index 3e47501f024f..a23628108272 100644
--- a/net/tipc/udp_media.c
+++ b/net/tipc/udp_media.c
@@ -730,8 +730,8 @@ static int tipc_udp_enable(struct net *net, struct tipc_bearer *b,
 			udp_conf.local_ip.s_addr = local.ipv4.s_addr;
 		udp_conf.use_udp_checksums = false;
 		ub->ifindex = dev->ifindex;
-		b->encap_hlen = sizeof(struct iphdr) + sizeof(struct udphdr);
-		if (tipc_mtu_bad(dev, b->encap_hlen)) {
+		if (tipc_mtu_bad(dev, sizeof(struct iphdr) +
+				      sizeof(struct udphdr))) {
 			err = -EINVAL;
 			goto err;
 		}
@@ -752,7 +752,6 @@ static int tipc_udp_enable(struct net *net, struct tipc_bearer *b,
 		else
 			udp_conf.local_ip6 = local.ipv6;
 		ub->ifindex = dev->ifindex;
-		b->encap_hlen = sizeof(struct ipv6hdr) + sizeof(struct udphdr);
 		b->mtu = 1280;
 #endif
 	} else {