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Message-ID: <20250130035130.180676-6-ebiggers@kernel.org>
Date: Wed, 29 Jan 2025 19:51:24 -0800
From: Eric Biggers <ebiggers@...nel.org>
To: linux-kernel@...r.kernel.org
Cc: linux-crypto@...r.kernel.org,
x86@...nel.org,
linux-block@...r.kernel.org,
Ard Biesheuvel <ardb@...nel.org>,
Keith Busch <kbusch@...nel.org>,
Kent Overstreet <kent.overstreet@...ux.dev>,
"Martin K . Petersen" <martin.petersen@...cle.com>
Subject: [PATCH v2 05/11] lib/crc64: add support for arch-optimized implementations
From: Eric Biggers <ebiggers@...gle.com>
Add support for architecture-optimized implementations of the CRC64
library functions, following the approach taken for the CRC32 and
CRC-T10DIF library functions.
Also take the opportunity to tweak the function prototypes:
- Use 'const void *' for the lib entry points (since this is easier for
users) but 'const u8 *' for the underlying arch and generic functions
(since this is easier for the implementations of these functions).
- Don't bother with __pure. It's an unusual optimization that doesn't
help properly written code. It's a weird quirk we can do without.
Signed-off-by: Eric Biggers <ebiggers@...gle.com>
---
include/linux/crc64.h | 26 ++++++++++++++++++++++----
lib/Kconfig | 7 +++++++
lib/crc64.c | 36 ++++++++----------------------------
3 files changed, 37 insertions(+), 32 deletions(-)
diff --git a/include/linux/crc64.h b/include/linux/crc64.h
index 17cf5af3e78e..41de30b907df 100644
--- a/include/linux/crc64.h
+++ b/include/linux/crc64.h
@@ -5,12 +5,28 @@
#ifndef _LINUX_CRC64_H
#define _LINUX_CRC64_H
#include <linux/types.h>
-u64 __pure crc64_be(u64 crc, const void *p, size_t len);
-u64 __pure crc64_nvme_generic(u64 crc, const void *p, size_t len);
+u64 crc64_be_arch(u64 crc, const u8 *p, size_t len);
+u64 crc64_be_generic(u64 crc, const u8 *p, size_t len);
+u64 crc64_nvme_arch(u64 crc, const u8 *p, size_t len);
+u64 crc64_nvme_generic(u64 crc, const u8 *p, size_t len);
+
+/**
+ * crc64_be - Calculate bitwise big-endian ECMA-182 CRC64
+ * @crc: seed value for computation. 0 or (u64)~0 for a new CRC calculation,
+ * or the previous crc64 value if computing incrementally.
+ * @p: pointer to buffer over which CRC64 is run
+ * @len: length of buffer @p
+ */
+static inline u64 crc64_be(u64 crc, const void *p, size_t len)
+{
+ if (IS_ENABLED(CONFIG_CRC64_ARCH))
+ return crc64_be_arch(crc, p, len);
+ return crc64_be_generic(crc, p, len);
+}
/**
* crc64_nvme - Calculate CRC64-NVME
* @crc: seed value for computation. 0 for a new CRC calculation, or the
* previous crc64 value if computing incrementally.
@@ -18,11 +34,13 @@ u64 __pure crc64_nvme_generic(u64 crc, const void *p, size_t len);
* @len: length of buffer @p
*
* This computes the CRC64 defined in the NVME NVM Command Set Specification,
* *including the bitwise inversion at the beginning and end*.
*/
-static inline u64 crc64_nvme(u64 crc, const u8 *p, size_t len)
+static inline u64 crc64_nvme(u64 crc, const void *p, size_t len)
{
- return crc64_nvme_generic(crc, p, len);
+ if (IS_ENABLED(CONFIG_CRC64_ARCH))
+ return ~crc64_nvme_arch(~crc, p, len);
+ return ~crc64_nvme_generic(~crc, p, len);
}
#endif /* _LINUX_CRC64_H */
diff --git a/lib/Kconfig b/lib/Kconfig
index da07fd39cf97..67bbf4f64dd9 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -199,10 +199,17 @@ config CRC64
This option is provided for the case where no in-kernel-tree
modules require CRC64 functions, but a module built outside
the kernel tree does. Such modules that use library CRC64
functions require M here.
+config ARCH_HAS_CRC64
+ bool
+
+config CRC64_ARCH
+ tristate
+ default CRC64 if ARCH_HAS_CRC64 && CRC_OPTIMIZATIONS
+
config CRC4
tristate "CRC4 functions"
help
This option is provided for the case where no in-kernel-tree
modules require CRC4 functions, but a module built outside
diff --git a/lib/crc64.c b/lib/crc64.c
index d6f3f245eede..5b1b17057f0a 100644
--- a/lib/crc64.c
+++ b/lib/crc64.c
@@ -39,40 +39,20 @@
#include "crc64table.h"
MODULE_DESCRIPTION("CRC64 calculations");
MODULE_LICENSE("GPL v2");
-/**
- * crc64_be - Calculate bitwise big-endian ECMA-182 CRC64
- * @crc: seed value for computation. 0 or (u64)~0 for a new CRC calculation,
- * or the previous crc64 value if computing incrementally.
- * @p: pointer to buffer over which CRC64 is run
- * @len: length of buffer @p
- */
-u64 __pure crc64_be(u64 crc, const void *p, size_t len)
+u64 crc64_be_generic(u64 crc, const u8 *p, size_t len)
{
- size_t i, t;
-
- const unsigned char *_p = p;
-
- for (i = 0; i < len; i++) {
- t = ((crc >> 56) ^ (*_p++)) & 0xFF;
- crc = crc64table[t] ^ (crc << 8);
- }
-
+ while (len--)
+ crc = (crc << 8) ^ crc64table[(crc >> 56) ^ *p++];
return crc;
}
-EXPORT_SYMBOL_GPL(crc64_be);
+EXPORT_SYMBOL_GPL(crc64_be_generic);
-u64 __pure crc64_nvme_generic(u64 crc, const void *p, size_t len)
+u64 crc64_nvme_generic(u64 crc, const u8 *p, size_t len)
{
- const unsigned char *_p = p;
- size_t i;
-
- crc = ~crc;
-
- for (i = 0; i < len; i++)
- crc = (crc >> 8) ^ crc64nvmetable[(crc & 0xff) ^ *_p++];
-
- return ~crc;
+ while (len--)
+ crc = (crc >> 8) ^ crc64nvmetable[(crc & 0xff) ^ *p++];
+ return crc;
}
EXPORT_SYMBOL_GPL(crc64_nvme_generic);
--
2.48.1
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