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From:   Isabella Basso <isabbasso@riseup.net>
To:     geert@linux-m68k.org
Cc:     ferreiraenzoa@gmail.com, augusto.duraes33@gmail.com,
        brendanhiggins@google.com, dlatypov@google.com,
        davidgow@google.com, linux-kselftest@vger.kernel.org,
        linux-kernel@vger.kernel.org, kunit-dev@googlegroups.com,
        ~lkcamp/patches@lists.sr.ht, rodrigosiqueiramelo@gmail.com,
        akpm@linux-foundation.org, skhan@linuxfoundation.org,
        Isabella Basso <isabellabdoamaral@usp.br>,
        Isabella Basso <isabbasso@riseup.net>
Subject: [PATCH v3 1/5] hash.h: remove unused define directive
Date:   Thu, 28 Oct 2021 19:25:29 -0300
Message-Id: <20211028222533.432641-2-isabbasso@riseup.net>
In-Reply-To: <20211028222533.432641-1-isabbasso@riseup.net>
References: <20211028222533.432641-1-isabbasso@riseup.net>
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From: Isabella Basso <isabellabdoamaral@usp.br>

Currently, there exist hash_32() and __hash_32() functions, which were
introduced in a patch [1] targeting architecture specific optimizations.
These functions can be overridden on a per-architecture basis to achieve
such optimizations. They must set their corresponding define directive
(HAVE_ARCH_HASH_32 and HAVE_ARCH__HASH_32, respectively) so that header
files can deal with these overrides properly.

As the supported 32-bit architectures that have their own hash function
implementation (i.e. m68k, Microblaze, H8/300, pa-risc) have only been
making use of the (more general) __hash_32() function (which only lacks
a right shift operation when compared to the hash_32() function),
remove the define directive corresponding to the arch-specific hash_32()
implementation.

[1] https://lore.kernel.org/lkml/20160525073311.5600.qmail@ns.sciencehorizons.net/

Reviewed-by: David Gow <davidgow@google.com>
Tested-by: David Gow <davidgow@google.com>
Co-developed-by: Augusto Durães Camargo <augusto.duraes33@gmail.com>
Signed-off-by: Augusto Durães Camargo <augusto.duraes33@gmail.com>
Co-developed-by: Enzo Ferreira <ferreiraenzoa@gmail.com>
Signed-off-by: Enzo Ferreira <ferreiraenzoa@gmail.com>
Signed-off-by: Isabella Basso <isabbasso@riseup.net>
---
Changes since v1:
- As suggested by David Gow:
  1. Reword commit message.

 include/linux/hash.h       |  5 +----
 lib/test_hash.c            | 24 +-----------------------
 tools/include/linux/hash.h |  5 +----
 3 files changed, 3 insertions(+), 31 deletions(-)

diff --git a/include/linux/hash.h b/include/linux/hash.h
index ad6fa21d977b..38edaa08f862 100644
--- a/include/linux/hash.h
+++ b/include/linux/hash.h
@@ -62,10 +62,7 @@ static inline u32 __hash_32_generic(u32 val)
 	return val * GOLDEN_RATIO_32;
 }

-#ifndef HAVE_ARCH_HASH_32
-#define hash_32 hash_32_generic
-#endif
-static inline u32 hash_32_generic(u32 val, unsigned int bits)
+static inline u32 hash_32(u32 val, unsigned int bits)
 {
 	/* High bits are more random, so use them. */
 	return __hash_32(val) >> (32 - bits);
diff --git a/lib/test_hash.c b/lib/test_hash.c
index 0ee40b4a56dd..d4b0cfdb0377 100644
--- a/lib/test_hash.c
+++ b/lib/test_hash.c
@@ -94,22 +94,7 @@ test_int_hash(unsigned long long h64, u32 hash_or[2][33])
 			pr_err("hash_32(%#x, %d) = %#x > %#x", h0, k, h1, m);
 			return false;
 		}
-#ifdef HAVE_ARCH_HASH_32
-		h2 = hash_32_generic(h0, k);
-#if HAVE_ARCH_HASH_32 == 1
-		if (h1 != h2) {
-			pr_err("hash_32(%#x, %d) = %#x != hash_32_generic() "
-				" = %#x", h0, k, h1, h2);
-			return false;
-		}
-#else
-		if (h2 > m) {
-			pr_err("hash_32_generic(%#x, %d) = %#x > %#x",
-				h0, k, h1, m);
-			return false;
-		}
-#endif
-#endif
+
 		/* Test hash_64 */
 		hash_or[1][k] |= h1 = hash_64(h64, k);
 		if (h1 > m) {
@@ -227,13 +212,6 @@ test_hash_init(void)
 #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
-#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.");
diff --git a/tools/include/linux/hash.h b/tools/include/linux/hash.h
index ad6fa21d977b..38edaa08f862 100644
--- a/tools/include/linux/hash.h
+++ b/tools/include/linux/hash.h
@@ -62,10 +62,7 @@ static inline u32 __hash_32_generic(u32 val)
 	return val * GOLDEN_RATIO_32;
 }

-#ifndef HAVE_ARCH_HASH_32
-#define hash_32 hash_32_generic
-#endif
-static inline u32 hash_32_generic(u32 val, unsigned int bits)
+static inline u32 hash_32(u32 val, unsigned int bits)
 {
 	/* High bits are more random, so use them. */
 	return __hash_32(val) >> (32 - bits);
--
2.33.1