Re: [PATCH net-next 0/4] tcp: listener refactor part 16

[David Miller <davem@davemloft.net>]

From: David Miller <davem@davemloft.net>
Date: Tue, 24 Mar 2015 15:02:57 -0400 (EDT)

> From: Eric Dumazet <edumazet@google.com>
> Date: Mon, 23 Mar 2015 21:34:22 -0700
> 
>> I added const qualifiers to various md5 methods, as I expect
>> to call them on behalf of request sock traffic even if
>> the listener socket is not locked. This seems ok, but adding
>> const makes the contract clearer. Note a good reduction
>> of code size thanks to request/establish sockets convergence.
> 
> Series applied, keep up the good work Eric.

Actually, I have to back this out.

You can't mark all of these things const, because of lockdep:

kernel/Makefile:133: *** No X.509 certificates found ***
net/ipv4/tcp_ipv4.c: In function ‘tcp_md5_do_lookup’:
net/ipv4/tcp_ipv4.c:907:2: warning: passing argument 1 of ‘lock_is_held’ discards ‘const’ qualifier from pointer target type [enabled by default]
In file included from include/linux/spinlock_types.h:18:0,
                 from include/linux/spinlock.h:81,
                 from include/linux/seqlock.h:35,
                 from include/linux/time.h:5,
                 from include/linux/stat.h:18,
                 from include/linux/module.h:10,
                 from net/ipv4/tcp_ipv4.c:58:
include/linux/lockdep.h:341:12: note: expected ‘struct lockdep_map *’ but argument is of type ‘const struct lockdep_map *’