Commit Graph

4 Commits

Author SHA1 Message Date
Geert Uytterhoeven e6173ba42b lib/test_hash.c: fix warning in preprocessor symbol evaluation
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: 468a942852 ("<linux/hash.h>: Add support for architecture-specific functions")
Link: http://lkml.kernel.org/r/20160829214952.1334674-4-arnd@arndb.de
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: George Spelvin <linux@sciencehorizons.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-09-01 17:52:01 -07:00
Geert Uytterhoeven ed76b7a131 lib/test_hash.c: fix warning in two-dimensional array init
lib/test_hash.c: In function 'test_hash_init':
  lib/test_hash.c:146:2: warning: missing braces around initializer [-Wmissing-braces]

Fixes: 468a942852 ("<linux/hash.h>: Add support for architecture-specific functions")
Link: http://lkml.kernel.org/r/20160829214952.1334674-3-arnd@arndb.de
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: George Spelvin <linux@sciencehorizons.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-09-01 17:52:01 -07:00
Linus Torvalds 8387ff2577 vfs: make the string hashes salt the hash
We always mixed in the parent pointer into the dentry name hash, but we
did it late at lookup time.  It turns out that we can simplify that
lookup-time action by salting the hash with the parent pointer early
instead of late.

A few other users of our string hashes also wanted to mix in their own
pointers into the hash, and those are updated to use the same mechanism.

Hash users that don't have any particular initial salt can just use the
NULL pointer as a no-salt.

Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: George Spelvin <linux@sciencehorizons.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-10 20:21:46 -07:00
George Spelvin 468a942852 <linux/hash.h>: Add support for architecture-specific functions
This is just the infrastructure; there are no users yet.

This is modelled on CONFIG_ARCH_RANDOM; a CONFIG_ symbol declares
the existence of <asm/hash.h>.

That file may define its own versions of various functions, and define
HAVE_* symbols (no CONFIG_ prefix!) to suppress the generic ones.

Included is a self-test (in lib/test_hash.c) that verifies the basics.
It is NOT in general required that the arch-specific functions compute
the same thing as the generic, but if a HAVE_* symbol is defined with
the value 1, then equality is tested.

Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Cc: Philippe De Muyter <phdm@macq.eu>
Cc: linux-m68k@lists.linux-m68k.org
Cc: Alistair Francis <alistai@xilinx.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: uclinux-h8-devel@lists.sourceforge.jp
2016-05-28 15:48:31 -04:00