net: tls: Avoid assigning 'const' pointer to non-const pointer

tls_build_proto() uses WRITE_ONCE() to assign a 'const' pointer to a
'non-const' pointer. Cleanups to the implementation of WRITE_ONCE() mean
that this will give rise to a compiler warning, just like a plain old
assignment would do:

  | net/tls/tls_main.c: In function ‘tls_build_proto’:
  | ./include/linux/compiler.h:229:30: warning: assignment discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
  | net/tls/tls_main.c:640:4: note: in expansion of macro ‘smp_store_release’
  |   640 |    smp_store_release(&saved_tcpv6_prot, prot);
  |       |    ^~~~~~~~~~~~~~~~~

Drop the const qualifier from the local 'prot' variable, as it isn't
needed.

Cc: Boris Pismenny <borisp@mellanox.com>
Cc: Aviad Yehezkel <aviadye@mellanox.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c
index 156efce50dbd10e134e13ba28afc802f78e9a4b5..b33e11c27cfa4a84b05a46bc5afd0f97ba78c855 100644 (file)
--- a/net/tls/tls_main.c
+++ b/net/tls/tls_main.c
@@ -629,7 +629,7 @@ struct tls_context *tls_ctx_create(struct sock *sk)
 static void tls_build_proto(struct sock *sk)
 {
        int ip_ver = sk->sk_family == AF_INET6 ? TLSV6 : TLSV4;
-       const struct proto *prot = READ_ONCE(sk->sk_prot);
+       struct proto *prot = READ_ONCE(sk->sk_prot);
 
        /* Build IPv6 TLS whenever the address of tcpv6 _prot changes */
        if (ip_ver == TLSV6 &&