[XFRM]: Optimize MTU calculation

Replace the probing based MTU estimation, which usually takes 2-3 iterations
to find a fitting value and may underestimate the MTU, by an exact calculation.

Also fix underestimation of the XFRM trailer_len, which causes unnecessary
reallocations.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 5a00aa85b756..e144a25814bd 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -279,7 +279,7 @@ struct xfrm_type
         xfrm_address_t          *(*local_addr)(struct xfrm_state *, xfrm_address_t *);
         xfrm_address_t          *(*remote_addr)(struct xfrm_state *, xfrm_address_t *);
         /* Estimate maximal size of result of transformation of a dgram */
-        u32                     (*get_max_size)(struct xfrm_state *, int size);
+        u32                     (*get_mtu)(struct xfrm_state *, int size);
 };
 
 extern int xfrm_register_type(struct xfrm_type *type, unsigned short family);