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From: "George Spelvin" <linux@sciencehorizons.net>
To: linux-kernel@vger.kernel.org, torvalds@linux-foundation.org
Cc: alistair.francis@xilinx.com, geert@linux-m68k.org,
	gerg@linux-m68k.org, linux-m68k@vger.kernel.org,
	linux@sciencehorizons.net, michal.simek@xilinx.com,
	tglx@linutronix.de, uclinux-h8-devel@lists.sourceforge.jp,
	ysato@users.sourceforge.jp
Subject: [PATCH 07/10] <linux/hash.h>: Add support for architecture-specific functions
Date: 25 May 2016 03:33:11 -0400	[thread overview]
Message-ID: <20160525073311.5600.qmail@ns.sciencehorizons.net> (raw)
In-Reply-To: <CA+55aFxPSW+84KfQ1N_WmND-wtvgj2zQm8nFPkRcc+gyU=uing@mail.gmail.com>

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/archhash.h>.

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

Signed-off-by: George Spelvin <linux@sciencehorizons.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greg Ungerer <gerg@linux-m68k.org>
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
---
 arch/Kconfig         |  8 ++++++++
 fs/namei.c           |  6 +++++-
 include/linux/hash.h | 11 +++++++++++
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index 81869a5e..33e8d7b1 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -589,6 +589,14 @@ config HAVE_STACK_VALIDATION
 	  Architecture supports the 'objtool check' host tool command, which
 	  performs compile-time stack metadata validation.
 
+config HAVE_ARCH_HASH
+	bool
+	default n
+	help
+	  If this is set, the architecture provides an <asm/archhash.h>
+	  file which provides platform-specific implementations of some
+	  functions in <linux/hash.h> or fs/namei.c.
+
 #
 # ABI hall of shame
 #
diff --git a/fs/namei.c b/fs/namei.c
index 2b8d0650..380e8057 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1788,7 +1788,11 @@ static int walk_component(struct nameidata *nd, int flags)
 
 #include <asm/word-at-a-time.h>
 
-#ifdef CONFIG_64BIT
+#ifdef HASH_MIX
+
+/* Architecture provides HASH_MIX and fold_hash() in <linux/hash.h> */
+
+#elif defined(CONFIG_64BIT)
 /*
  * Register pressure in the mixing function is an issue, particularly
  * on 32-bit x86, but almost any function requires one state value and
diff --git a/include/linux/hash.h b/include/linux/hash.h
index 8926f369..838bc84b 100644
--- a/include/linux/hash.h
+++ b/include/linux/hash.h
@@ -41,17 +41,27 @@
 #define GOLDEN_RATIO_32 0x61C88647
 #define GOLDEN_RATIO_64 0x61C8864680B583EBull
 
+#ifdef CONFIG_HAVE_ARCH_HASH
+/* This header may use the GOLDEN_RATIO_xx constants */
+#include <asm/archhash.h>
+#endif
+
+#ifndef HAVE_ARCH__HASH_32
 static inline u32 __hash_32(u32 val)
 {
 	return val * GOLDEN_RATIO_32;
 }
+#endif
 
+#ifndef HAVE_ARCH_HASH_32
 static inline u32 hash_32(u32 val, unsigned int bits)
 {
 	/* High bits are more random, so use them. */
 	return __hash_32(val) >> (32 - bits);
 }
+#endif
 
+#ifndef HAVE_ARCH_HASH_64
 static __always_inline u32 hash_64(u64 val, unsigned int bits)
 {
 	if (__builtin_constant_p(bits > 32 || bits == 0)) {
@@ -74,6 +84,7 @@ static __always_inline u32 hash_64(u64 val, unsigned int bits)
 	return hash_32((u32)val - __hash_32(val >> 32), bits);
 #endif
 }
+#endif
 
 static inline u32 hash_ptr(const void *ptr, unsigned int bits)
 {
-- 
2.8.1

  parent reply	other threads:[~2016-05-25  7:33 UTC|newest]

Thread overview: 55+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CA+55aFxPSW+84KfQ1N_WmND-wtvgj2zQm8nFPkRcc+gyU=uing@mail.gmail.com>
2016-05-25  7:20 ` [PATCH 00/10] String hash improvements George Spelvin
2016-05-25  8:00   ` Geert Uytterhoeven
2016-05-25  8:11     ` George Spelvin
2016-05-25  8:50       ` Geert Uytterhoeven
2016-05-25  9:07         ` George Spelvin
2016-05-25 16:08   ` Linus Torvalds
2016-05-28 19:57     ` [PATCH v3 " George Spelvin
2016-05-28 19:57       ` [PATCH v3 01/10] Pull out string hash to <linux/stringhash.h> George Spelvin
2016-05-28 19:57       ` [PATCH v3 02/10] fs/namei.c: Add hashlen_string() function George Spelvin
2016-05-28 19:57       ` [PATCH v3 03/10] <linux/sunrpc/svcauth.h>: Define hash_str() in terms of hashlen_string() George Spelvin
2016-05-28 19:57       ` [PATCH v3 04/10] Change hash_64() return value to 32 bits George Spelvin
2016-05-28 19:57       ` [PATCH v3 05/10] Eliminate bad hash multipliers from hash_32() and hash_64() George Spelvin
2016-05-28 19:57       ` [PATCH v3 06/10] fs/namei.c: Improve dcache hash function George Spelvin
2016-05-30 15:11         ` Peter Zijlstra
2016-05-30 16:06           ` George Spelvin
2016-05-30 16:27             ` Peter Zijlstra
2016-05-30 18:10               ` George Spelvin
2016-06-02  1:18                 ` Linus Torvalds
2016-06-02  2:31                   ` George Spelvin
2016-06-02 16:35                     ` Linus Torvalds
2016-06-02 18:23                       ` George Spelvin
2016-05-28 19:57       ` [PATCH v3 07/10] <linux/hash.h>: Add support for architecture-specific functions George Spelvin
2016-05-29  7:57         ` Geert Uytterhoeven
2016-05-28 19:57       ` [PATCH v3 08/10] m68k: Add <asm/hash.h> George Spelvin
2016-05-28 19:57       ` [PATCH v3 09/10] microblaze: " George Spelvin
2016-05-28 19:57       ` [PATCH v3 10/10] h8300: " George Spelvin
2016-05-28 20:47       ` [PATCH v3 00/10] String hash improvements Linus Torvalds
2016-05-28 20:54         ` George Spelvin
2016-06-02 22:59     ` [PATCH " Fubo Chen
2016-05-26 17:09   ` [PATCH v2 " George Spelvin
2016-05-25  7:21 ` [PATCH 01/10] Pull out string hash to <linux/stringhash.h> George Spelvin
2016-05-25  7:22 ` [PATCH 02/10] fs/namei.c: Add hash_string() function George Spelvin
2016-05-25  7:26 ` [PATCH 03/10] <linux/sunrpc/svcauth.h>: Define hash_str() in terms of hash_string() George Spelvin
2016-05-25  7:28 ` [PATCH 04/10] Change hash_64() return value to 32 bits George Spelvin
2016-05-25  7:29 ` [PATCH 05/10] Eliminate bad hash multipliers from hash_32() and hash_64() George Spelvin
2016-05-25  7:31 ` [PATCH 06/10] fs/namei.c: Improve dcache hash function George Spelvin
2016-05-25  7:33 ` George Spelvin [this message]
2016-05-26 17:16   ` [PATCH v2 07/10] <linux/hash.h>: Add support for architecture-specific functions George Spelvin
2016-05-25  7:34 ` [PATCH 08/10] m68k: Add <asm/archhash.h> George Spelvin
2016-05-25  7:34 ` George Spelvin
2016-05-25  8:07   ` Geert Uytterhoeven
2016-05-25  8:19     ` George Spelvin
2016-05-25  8:24     ` [PATCH 08v2/10] " George Spelvin
2016-05-25  8:48       ` Geert Uytterhoeven
2016-05-25  8:56   ` [PATCH 08/10] " Philippe De Muyter
2016-05-25  9:14     ` George Spelvin
2016-05-25  9:31       ` Andreas Schwab
2016-05-25  9:51       ` Philippe De Muyter
2016-05-25 13:24   ` Philippe De Muyter
2016-05-25 13:42     ` George Spelvin
2016-05-26 17:19   ` [PATCH v2 08/10] m68k: Add <asm/hash.h> George Spelvin
2016-05-25  7:37 ` [PATCH 09/10] microblaze: Add <asm/archhash.h> George Spelvin
2016-05-26 17:21   ` [PATCH v2 09/10] microblaze: Add <asm/hash.h> George Spelvin
2016-05-25  7:38 ` [PATCH 10/10] h8300: Add <asm/archhash.h> George Spelvin
2016-05-26 17:23   ` [PATCH v2 10/10] h8300: Add <asm/hash.h> George Spelvin

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