[PATCH 4.7 114/141] lib/test_hash.c: fix warning in preprocessor symbol evaluation

From: Greg Kroah-Hartman
Date: Thu Oct 06 2016 - 05:35:43 EST


4.7-stable review patch. If anyone has any objections, please let me know.

------------------

From: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>

commit e6173ba42bbdba05fd4f3021c0beda0506271507 upstream.

Some versions of gcc don't like tests for the value of an undefined
preprocessor symbol, even in the #else branch of an #ifndef:

lib/test_hash.c:224:7: warning: "HAVE_ARCH__HASH_32" is not defined [-Wundef]
#elif HAVE_ARCH__HASH_32 != 1
^
lib/test_hash.c:229:7: warning: "HAVE_ARCH_HASH_32" is not defined [-Wundef]
#elif HAVE_ARCH_HASH_32 != 1
^
lib/test_hash.c:234:7: warning: "HAVE_ARCH_HASH_64" is not defined [-Wundef]
#elif HAVE_ARCH_HASH_64 != 1
^

Seen with gcc 4.9, not seen with 4.1.2.

Change the logic to only check the value inside an #ifdef to fix this.

Fixes: 468a9428521e7d00 ("<linux/hash.h>: Add support for architecture-specific functions")
Link: http://lkml.kernel.org/r/20160829214952.1334674-4-arnd@xxxxxxxx
Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Acked-by: George Spelvin <linux@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
lib/test_hash.c | 24 +++++++++++++++---------
1 file changed, 15 insertions(+), 9 deletions(-)

--- a/lib/test_hash.c
+++ b/lib/test_hash.c
@@ -219,21 +219,27 @@ test_hash_init(void)
}

/* Issue notices about skipped tests. */
-#ifndef HAVE_ARCH__HASH_32
- pr_info("__hash_32() has no arch implementation to test.");
-#elif HAVE_ARCH__HASH_32 != 1
+#ifdef HAVE_ARCH__HASH_32
+#if HAVE_ARCH__HASH_32 != 1
pr_info("__hash_32() is arch-specific; not compared to generic.");
#endif
-#ifndef HAVE_ARCH_HASH_32
- pr_info("hash_32() has no arch implementation to test.");
-#elif HAVE_ARCH_HASH_32 != 1
+#else
+ pr_info("__hash_32() has no arch implementation to test.");
+#endif
+#ifdef HAVE_ARCH_HASH_32
+#if HAVE_ARCH_HASH_32 != 1
pr_info("hash_32() is arch-specific; not compared to generic.");
#endif
-#ifndef HAVE_ARCH_HASH_64
- pr_info("hash_64() has no arch implementation to test.");
-#elif HAVE_ARCH_HASH_64 != 1
+#else
+ pr_info("hash_32() has no arch implementation to test.");
+#endif
+#ifdef HAVE_ARCH_HASH_64
+#if HAVE_ARCH_HASH_64 != 1
pr_info("hash_64() is arch-specific; not compared to generic.");
#endif
+#else
+ pr_info("hash_64() has no arch implementation to test.");
+#endif

pr_notice("%u tests passed.", tests);