lib/crc: loongarch: Migrate optimized CRC code into lib/crc/

Move the loongarch-optimized CRC code from arch/loongarch/lib/crc* into
its new location in lib/crc/loongarch/, and wire it up in the new way.
This new way of organizing the CRC code eliminates the need to
artificially split the code for each CRC variant into separate arch and
generic modules, enabling better inlining and dead code elimination.
For more details, see "lib/crc: Prepare for arch-optimized code in
subdirs of lib/crc/".

Reviewed-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: "Jason A. Donenfeld" <Jason@zx2c4.com>
Link: https://lore.kernel.org/r/20250607200454.73587-6-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>

Author: Eric Biggers

arch/loongarch/Kconfig

@@ -15,7 +15,6 @@ config LOONGARCH
 	select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
 	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
 	select ARCH_HAS_CPU_FINALIZE_INIT
-	select ARCH_HAS_CRC32
 	select ARCH_HAS_CURRENT_STACK_POINTER
 	select ARCH_HAS_DEBUG_VM_PGTABLE
 	select ARCH_HAS_FAST_MULTIPLIER

arch/loongarch/lib/Makefile

@@ -11,5 +11,3 @@ obj-$(CONFIG_ARCH_SUPPORTS_INT128) += tishift.o
 obj-$(CONFIG_CPU_HAS_LSX) += xor_simd.o xor_simd_glue.o
 
 obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o
-
-obj-$(CONFIG_CRC32_ARCH) += crc32-loongarch.o

lib/crc/Kconfig

@@ -68,6 +68,7 @@ config CRC32_ARCH
 	depends on CRC32 && CRC_OPTIMIZATIONS
 	default y if ARM && KERNEL_MODE_NEON
 	default y if ARM64
+	default y if LOONGARCH
 
 config CRC64
 	tristate

arch/loongarch/lib/crc32-loongarch.c lib/crc/loongarch/crc32.harch/loongarch/lib/crc32-loongarch.c renamed to lib/crc/loongarch/crc32.h

@@ -10,9 +10,6 @@
  */
 
 #include <asm/cpu-features.h>
-#include <linux/crc32.h>
-#include <linux/export.h>
-#include <linux/module.h>
 #include <linux/unaligned.h>
 
 #define _CRC32(crc, value, size, type)			\
@@ -29,7 +26,7 @@ do {							\
 
 static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_crc32);
 
-u32 crc32_le_arch(u32 crc, const u8 *p, size_t len)
+static inline u32 crc32_le_arch(u32 crc, const u8 *p, size_t len)
 {
 	if (!static_branch_likely(&have_crc32))
 		return crc32_le_base(crc, p, len);
@@ -64,9 +61,8 @@ u32 crc32_le_arch(u32 crc, const u8 *p, size_t len)
 
 	return crc;
 }
-EXPORT_SYMBOL(crc32_le_arch);
 
-u32 crc32c_arch(u32 crc, const u8 *p, size_t len)
+static inline u32 crc32c_arch(u32 crc, const u8 *p, size_t len)
 {
 	if (!static_branch_likely(&have_crc32))
 		return crc32c_base(crc, p, len);
@@ -101,36 +97,19 @@ u32 crc32c_arch(u32 crc, const u8 *p, size_t len)
 
 	return crc;
 }
-EXPORT_SYMBOL(crc32c_arch);
 
-u32 crc32_be_arch(u32 crc, const u8 *p, size_t len)
-{
-	return crc32_be_base(crc, p, len);
-}
-EXPORT_SYMBOL(crc32_be_arch);
+#define crc32_be_arch crc32_be_base /* not implemented on this arch */
 
-static int __init crc32_loongarch_init(void)
+#define crc32_mod_init_arch crc32_mod_init_arch
+static inline void crc32_mod_init_arch(void)
 {
 	if (cpu_has_crc32)
 		static_branch_enable(&have_crc32);
-	return 0;
 }
-subsys_initcall(crc32_loongarch_init);
 
-static void __exit crc32_loongarch_exit(void)
-{
-}
-module_exit(crc32_loongarch_exit);
-
-u32 crc32_optimizations(void)
+static inline u32 crc32_optimizations_arch(void)
 {
 	if (static_key_enabled(&have_crc32))
 		return CRC32_LE_OPTIMIZATION | CRC32C_OPTIMIZATION;
 	return 0;
 }
-EXPORT_SYMBOL(crc32_optimizations);
-
-MODULE_AUTHOR("Min Zhou <zhoumin@loongson.cn>");
-MODULE_AUTHOR("Huacai Chen <chenhuacai@loongson.cn>");
-MODULE_DESCRIPTION("CRC32 and CRC32C using LoongArch crc* instructions");
-MODULE_LICENSE("GPL v2");