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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>,
	Segher Boessenkool <segher@kernel.crashing.org>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Peter Oberparleiter <oberpar@linux.ibm.com>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Pablo Neira Ayuso <pablo@netfilter.org>,
	Jozsef Kadlecsik <kadlec@netfilter.org>,
	Florian Westphal <fw@strlen.de>,
	"David S. Miller" <davem@davemloft.net>
Subject: [PATCH v2 02/10] netfilter: Avoid assigning 'const' pointer to non-const pointer
Date: Thu, 23 Jan 2020 15:33:33 +0000	[thread overview]
Message-ID: <20200123153341.19947-3-will@kernel.org> (raw)
In-Reply-To: <20200123153341.19947-1-will@kernel.org>

nf_remove_net_hook() 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:

  | In file included from ./include/linux/export.h:43,
  |                  from ./include/linux/linkage.h:7,
  |                  from ./include/linux/kernel.h:8,
  |                  from net/netfilter/core.c:9:
  | net/netfilter/core.c: In function ‘nf_remove_net_hook’:
  | ./include/linux/compiler.h:216:30: warning: assignment discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
  |   *(volatile typeof(x) *)&(x) = (val);  \
  |                               ^
  | net/netfilter/core.c:379:3: note: in expansion of macro ‘WRITE_ONCE’
  |    WRITE_ONCE(orig_ops[i], &dummy_ops);
  |    ^~~~~~~~~~

Follow the pattern used elsewhere in this file and add a cast to 'void *'
to squash the warning.

Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Jozsef Kadlecsik <kadlec@netfilter.org>
Cc: Florian Westphal <fw@strlen.de>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Will Deacon <will@kernel.org>
---
 net/netfilter/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netfilter/core.c b/net/netfilter/core.c
index 78f046ec506f..3ac7c8c1548d 100644
--- a/net/netfilter/core.c
+++ b/net/netfilter/core.c
@@ -376,7 +376,7 @@ static bool nf_remove_net_hook(struct nf_hook_entries *old,
 		if (orig_ops[i] != unreg)
 			continue;
 		WRITE_ONCE(old->hooks[i].hook, accept_all);
-		WRITE_ONCE(orig_ops[i], &dummy_ops);
+		WRITE_ONCE(orig_ops[i], (void *)&dummy_ops);
 		return true;
 	}
 
-- 
2.25.0.341.g760bfbb309-goog


  parent reply	other threads:[~2020-01-23 15:34 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-23 15:33 [PATCH v2 00/10] Rework READ_ONCE() to improve codegen Will Deacon
2020-01-23 15:33 ` [PATCH v2 01/10] compiler/gcc: Emit build-time warning for GCC prior to version 4.8 Will Deacon
2020-01-23 15:33 ` Will Deacon [this message]
2020-01-23 19:07   ` [PATCH v2 02/10] netfilter: Avoid assigning 'const' pointer to non-const pointer Nick Desaulniers
2020-01-24  8:24     ` Peter Zijlstra
2020-01-24 17:20       ` Nick Desaulniers
2020-01-27 12:04         ` David Laight
2020-01-24 17:36       ` Linus Torvalds
2020-01-24 22:00         ` Peter Zijlstra
2020-01-27 12:21         ` David Laight
2020-01-23 15:33 ` [PATCH v2 03/10] fault_inject: Don't rely on "return value" from WRITE_ONCE() Will Deacon
2020-01-23 15:33 ` [PATCH v2 04/10] READ_ONCE: Simplify implementations of {READ,WRITE}_ONCE() Will Deacon
2020-01-23 15:33 ` [PATCH v2 05/10] READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses Will Deacon
2020-01-25  8:27   ` Peter Zijlstra
2020-01-29 10:49     ` Peter Zijlstra
2020-01-23 15:33 ` [PATCH v2 06/10] READ_ONCE: Drop pointer qualifiers when reading from scalar types Will Deacon
2020-01-23 15:33 ` [PATCH v2 07/10] locking/barriers: Use '__unqual_scalar_typeof' for load-acquire macros Will Deacon
2020-01-23 15:33 ` [PATCH v2 08/10] arm64: barrier: Use '__unqual_scalar_typeof' for acquire/release macros Will Deacon
2020-01-23 15:33 ` [PATCH v2 09/10] compiler/gcc: Raise minimum GCC version for kernel builds to 4.8 Will Deacon
2020-01-23 18:36   ` Nick Desaulniers
2020-01-24  8:26     ` Peter Zijlstra
2020-01-24 17:05       ` Nick Desaulniers
2020-01-24 23:29         ` Peter Zijlstra
2020-01-25 10:34         ` Michael Ellerman
2020-01-23 15:33 ` [PATCH v2 10/10] gcov: Remove old GCC 3.4 support Will Deacon
2020-01-23 18:51   ` Nick Desaulniers
2020-01-28 14:56   ` Peter Oberparleiter
2020-01-23 17:07 ` [PATCH v2 00/10] Rework READ_ONCE() to improve codegen David Laight
2020-01-23 17:16   ` Will Deacon
2020-01-23 17:32     ` David Laight
2020-01-23 18:45       ` Nick Desaulniers
2020-01-23 19:01         ` Arvind Sankar
2020-01-24 10:11           ` David Laight
2020-01-26  1:10           ` Qais Yousef
2020-01-27  7:26             ` Arnd Bergmann
2020-01-23 17:59 ` Linus Torvalds
2020-01-24  8:33   ` Peter Zijlstra
2020-01-24 10:41     ` Peter Zijlstra
2020-02-10  9:50     ` Masahiro Yamada
2020-02-10  9:50       ` Masahiro Yamada
2020-02-10  9:59       ` Will Deacon
2020-01-31 10:20 ` David Howells

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