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From:   Vitaly Chikunov <vt@altlinux.org>
To:     Arnaldo Carvalho de Melo <acme@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>, linux-kernel@vger.kernel.org
Cc:     "Dmitry V . Levin" <ldv@altlinux.org>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Vineet Gupta <Vineet.Gupta1@synopsys.com>,
        stable@vger.kernel.org
Subject: [PATCH] tools lib: Disable redundant-delcs error for strlcpy
Date:   Mon,  9 Dec 2019 00:46:07 +0300
Message-Id: <20191208214607.20679-1-vt@altlinux.org>
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Disable `redundant-decls' error for strlcpy declaration and solve build
error allowing users to compile vanilla kernels.

When glibc have strlcpy (such as in ALT linux since 2004) objtool and
perf build fails with something like:

  In file included from exec-cmd.c:3:
  tools/include/linux/string.h:20:15: error: redundant redeclaration of ‘strlcpy’ [-Werror=redundant-decls]
     20 | extern size_t strlcpy(char *dest, const char *src, size_t size);
	|               ^~~~~~~

It's very hard to produce a perfect fix for that since it is a header
file indirectly pulled from many sources from different Makefile builds.

Fixes: ce99091 ("perf tools: Move strlcpy() from perf to tools/lib/string.c")
Fixes: 0215d59 ("tools lib: Reinstate strlcpy() header guard with __UCLIBC__")
Signed-off-by: Vitaly Chikunov <vt@altlinux.org>
Cc: Dmitry V. Levin <ldv@altlinux.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Cc: stable@vger.kernel.org
---
 tools/include/linux/string.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/include/linux/string.h b/tools/include/linux/string.h
index 980cb9266718..99ede7f5dfb8 100644
--- a/tools/include/linux/string.h
+++ b/tools/include/linux/string.h
@@ -17,7 +17,10 @@ int strtobool(const char *s, bool *res);
  * However uClibc headers also define __GLIBC__ hence the hack below
  */
 #if defined(__GLIBC__) && !defined(__UCLIBC__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wredundant-decls"
 extern size_t strlcpy(char *dest, const char *src, size_t size);
+#pragma GCC diagnostic pop
 #endif
 
 char *str_error_r(int errnum, char *buf, size_t buflen);
-- 
2.11.0