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From:   Will Deacon <will@kernel.org>
To:     linux-kernel@vger.kernel.org
Cc:     linux-arch@vger.kernel.org, kernel-team@android.com,
        Will Deacon <will@kernel.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Peter Zijlstra <peterz@infradead.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
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        Arnd Bergmann <arnd@arndb.de>,
        Peter Oberparleiter <oberpar@linux.ibm.com>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Boris Pismenny <borisp@mellanox.com>,
        Aviad Yehezkel <aviadye@mellanox.com>,
        John Fastabend <john.fastabend@gmail.com>,
        Daniel Borkmann <daniel@iogearbox.net>
Subject: [PATCH v3 03/12] net: tls: Avoid assigning 'const' pointer to non-const pointer
Date:   Wed, 15 Apr 2020 17:52:09 +0100
Message-Id: <20200415165218.20251-4-will@kernel.org>
In-Reply-To: <20200415165218.20251-1-will@kernel.org>
References: <20200415165218.20251-1-will@kernel.org>
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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>
---
 net/tls/tls_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/tls/tls_main.c b/net/tls/tls_main.c
index 156efce50dbd..b33e11c27cfa 100644
--- 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 &&
-- 
2.26.0.110.g2183baf09c-goog