error to use kmem_free() function

[#ZHANG CHUNLEI#]

I have modified  tcp_subr.c function , in which i make use of kmem_free(kmem_map,  , ) function.

However, the compiling error says: 

wanrning: implicit declaration of kmem_free() function and kmem_map undeclared. 

do i miss including some header file or other reasons?

thanks in advance. 

chunlei