bitmap updates for v6.20

- more rust helpers (Alice);
  - more bitops tests (Ryota);
  - FIND_NTH_BIT() uninitialized variable fix (Lee Yongjun);
  - random cleanups (Andy, H. Peter).
 -----BEGIN PGP SIGNATURE-----
 
 iQGzBAABCgAdFiEEi8GdvG6xMhdgpu/4sUSA/TofvsgFAmmJIqMACgkQsUSA/Tof
 vsj/uwv/WIv9Wa3oTm3qzkIyaxeowIQE+DeDduporSoO8fnVfEYHjPuihMy3J5Gv
 x6iNUq9n8fMhmg/qHHyKwb/Ow8Ob11re9MZWS6a02wlm8Het0W9hKEk1z7qauFsI
 Vqq3rlMO3wYGaSPmlnh7rn/NHByrJ49ZrJcoX3he0Ov5MKp1w+dP3Czee4HGTb3A
 SM0cf4iCR3/Jj3flTsMghZgqZKNhsIe+ejX++dFPhmv82FHbIBcwUfN6CM27OGdy
 M7GAro1xIaoTwQVKCO2AycLAu8j+Rx9s+mcGuIAWynDo6YG1tVetADZQ+nRJG+x9
 WdUDZwBDyEZlx/8BGnS56wevYxXEfC0lMTTgBqsYlCtLToyeE8G6NUVCLzEJAQCJ
 iWhcsenQVIiEHtYBZI/o2PmEp1Puzk1jI0+uFib1jE5Llf3+FrfMQGOiN2TBStEa
 zVIOipr+L9EaBbJdiKCV1jTl/MoDuCdRPLyby8egxPS+rk4RugvDsGc31XN48118
 OHIJO2M/
 =WnLV
 -----END PGP SIGNATURE-----

Merge tag 'bitmap-for-6.20' of https://github.com/norov/linux

Pull bitmap updates from Yury Norov:

 - more rust helpers (Alice)

 - more bitops tests (Ryota)

 - FIND_NTH_BIT() uninitialized variable fix (Lee Yongjun)

 - random cleanups (Andy, H. Peter)

* tag 'bitmap-for-6.20' of https://github.com/norov/linux:
  lib/tests: extend KUnit test for bitops with more cases
  bitops: Add more files to the MAINTAINERS
  lib/find_bit: fix uninitialized variable use in FIND_NTH_BIT
  lib/tests: add KUnit test for bitops
  rust: cpumask: add __rust_helper to helpers
  rust: bitops: add __rust_helper to helpers
  rust: bitmap: add __rust_helper to helpers
  linux/bitfield.h: replace __auto_type with auto

MAINTAINERS

@@ -4472,8 +4472,10 @@ F:	arch/*/lib/bitops.c
 F:	include/asm-generic/bitops
 F:	include/asm-generic/bitops.h
 F:	include/linux/bitops.h
+F:	include/linux/count_zeros.h
 F:	lib/hweight.c
 F:	lib/test_bitops.c
+F:	lib/tests/bitops_kunit.c
 F:	tools/*/bitops*
 
 BITOPS API BINDINGS [RUST]

include/linux/bitfield.h

@@ -8,6 +8,7 @@
 #define _LINUX_BITFIELD_H
 
 #include <linux/build_bug.h>
+#include <linux/compiler.h>
 #include <linux/typecheck.h>
 #include <asm/byteorder.h>
 
@@ -243,7 +244,7 @@ __MAKE_OP(64)
 
 #define __field_prep(mask, val)						\
 	({								\
-		__auto_type __mask = (mask);				\
+		auto __mask = (mask);					\
 		typeof(__mask) __val = (val);				\
 		unsigned int __shift = BITS_PER_TYPE(__mask) <= 32 ?	\
 				       __ffs(__mask) : __ffs64(__mask);	\
@@ -252,7 +253,7 @@ __MAKE_OP(64)
 
 #define __field_get(mask, reg)						\
 	({								\
-		__auto_type __mask = (mask);				\
+		auto __mask = (mask);					\
 		typeof(__mask) __reg =  (reg);				\
 		unsigned int __shift = BITS_PER_TYPE(__mask) <= 32 ?	\
 				       __ffs(__mask) : __ffs64(__mask);	\

lib/Kconfig.debug

@@ -2647,6 +2647,19 @@ config TEST_SYSCTL
 
 	  If unsure, say N.
 
+config BITOPS_KUNIT
+	tristate "KUnit test for bitops" if !KUNIT_ALL_TESTS
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
+	help
+	  This option enables the KUnit test for the bitops library
+	  which provides functions for bit operations.
+
+	  Note that this is derived from the original test_bitops module.
+	  For micro-benchmarks and compiler warning checks, enable TEST_BITOPS.
+
+	  If unsure, say N.
+
 config BITFIELD_KUNIT
 	tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
 	depends on KUNIT

lib/find_bit.c

@@ -71,7 +71,7 @@ out:										\
 
 #define FIND_NTH_BIT(FETCH, size, num)						\
 ({										\
-	unsigned long sz = (size), nr = (num), idx, w, tmp;			\
+	unsigned long sz = (size), nr = (num), idx, w, tmp = 0;			\
 										\
 	for (idx = 0; (idx + 1) * BITS_PER_LONG <= sz; idx++) {			\
 		if (idx * BITS_PER_LONG + nr >= sz)				\

lib/tests/Makefile

@@ -5,6 +5,7 @@
 # KUnit tests
 CFLAGS_bitfield_kunit.o := $(DISABLE_STRUCTLEAK_PLUGIN)
 obj-$(CONFIG_BASE64_KUNIT) += base64_kunit.o
+obj-$(CONFIG_BITOPS_KUNIT) += bitops_kunit.o
 obj-$(CONFIG_BITFIELD_KUNIT) += bitfield_kunit.o
 obj-$(CONFIG_BITS_TEST) += test_bits.o
 obj-$(CONFIG_BLACKHOLE_DEV_KUNIT_TEST) += blackhole_dev_kunit.o

lib/tests/bitops_kunit.c

@@ -0,0 +1,205 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 Intel Corporation
+ * Copyright (C) 2026 Ryota Sakamoto <sakamo.ryota@gmail.com>
+ */
+
+#include <linux/bitops.h>
+#include <linux/module.h>
+#include <kunit/test.h>
+
+/* use an enum because that's the most common BITMAP usage */
+enum bitops_fun {
+	BITOPS_4 = 4,
+	BITOPS_7 = 7,
+	BITOPS_11 = 11,
+	BITOPS_31 = 31,
+	BITOPS_88 = 88,
+	BITOPS_LENGTH = 256
+};
+
+struct bitops_test_case {
+	const char *str;
+	const long nr;
+};
+
+static struct bitops_test_case bitops_cases[] = {
+	{
+		.str = "BITOPS_4",
+		.nr = BITOPS_4,
+	},
+	{
+		.str = "BITOPS_7",
+		.nr = BITOPS_7,
+	},
+	{
+		.str = "BITOPS_11",
+		.nr = BITOPS_11,
+	},
+	{
+		.str = "BITOPS_31",
+		.nr = BITOPS_31,
+	},
+	{
+		.str = "BITOPS_88",
+		.nr = BITOPS_88,
+	},
+};
+
+KUNIT_ARRAY_PARAM_DESC(bitops, bitops_cases, str);
+
+static void test_set_bit_clear_bit(struct kunit *test)
+{
+	const struct bitops_test_case *params = test->param_value;
+	DECLARE_BITMAP(bitmap, BITOPS_LENGTH);
+	int bit_set;
+
+	bitmap_zero(bitmap, BITOPS_LENGTH);
+
+	set_bit(params->nr, bitmap);
+	KUNIT_EXPECT_TRUE(test, test_bit(params->nr, bitmap));
+
+	clear_bit(params->nr, bitmap);
+	KUNIT_EXPECT_FALSE(test, test_bit(params->nr, bitmap));
+
+	bit_set = find_first_bit(bitmap, BITOPS_LENGTH);
+	KUNIT_EXPECT_EQ(test, bit_set, BITOPS_LENGTH);
+}
+
+static void test_change_bit(struct kunit *test)
+{
+	const struct bitops_test_case *params = test->param_value;
+	DECLARE_BITMAP(bitmap, BITOPS_LENGTH);
+	int bit_set;
+
+	bitmap_zero(bitmap, BITOPS_LENGTH);
+
+	change_bit(params->nr, bitmap);
+	KUNIT_EXPECT_TRUE(test, test_bit(params->nr, bitmap));
+
+	change_bit(params->nr, bitmap);
+	KUNIT_EXPECT_FALSE(test, test_bit(params->nr, bitmap));
+
+	bit_set = find_first_bit(bitmap, BITOPS_LENGTH);
+	KUNIT_EXPECT_EQ(test, bit_set, BITOPS_LENGTH);
+}
+
+static void test_test_and_set_bit_test_and_clear_bit(struct kunit *test)
+{
+	const struct bitops_test_case *params = test->param_value;
+	DECLARE_BITMAP(bitmap, BITOPS_LENGTH);
+	int bit_set;
+
+	bitmap_zero(bitmap, BITOPS_LENGTH);
+
+	KUNIT_EXPECT_FALSE(test, test_and_set_bit(params->nr, bitmap));
+	KUNIT_EXPECT_TRUE(test, test_bit(params->nr, bitmap));
+
+	KUNIT_EXPECT_TRUE(test, test_and_set_bit(params->nr, bitmap));
+	KUNIT_EXPECT_TRUE(test, test_bit(params->nr, bitmap));
+
+	KUNIT_EXPECT_TRUE(test, test_and_clear_bit(params->nr, bitmap));
+	KUNIT_EXPECT_FALSE(test, test_bit(params->nr, bitmap));
+
+	KUNIT_EXPECT_FALSE(test, test_and_clear_bit(params->nr, bitmap));
+	KUNIT_EXPECT_FALSE(test, test_bit(params->nr, bitmap));
+
+	bit_set = find_first_bit(bitmap, BITOPS_LENGTH);
+	KUNIT_EXPECT_EQ(test, bit_set, BITOPS_LENGTH);
+}
+
+static void test_test_and_change_bit(struct kunit *test)
+{
+	const struct bitops_test_case *params = test->param_value;
+	DECLARE_BITMAP(bitmap, BITOPS_LENGTH);
+	int bit_set;
+
+	bitmap_zero(bitmap, BITOPS_LENGTH);
+
+	KUNIT_EXPECT_FALSE(test, test_and_change_bit(params->nr, bitmap));
+	KUNIT_EXPECT_TRUE(test, test_bit(params->nr, bitmap));
+
+	KUNIT_EXPECT_TRUE(test, test_and_change_bit(params->nr, bitmap));
+	KUNIT_EXPECT_FALSE(test, test_bit(params->nr, bitmap));
+
+	bit_set = find_first_bit(bitmap, BITOPS_LENGTH);
+	KUNIT_EXPECT_EQ(test, bit_set, BITOPS_LENGTH);
+}
+
+struct order_test_case {
+	const char *str;
+	const unsigned int count;
+	const int expected;
+};
+
+static struct order_test_case order_test_cases[] = {
+	{"0x00000003", 0x00000003,  2},
+	{"0x00000004", 0x00000004,  2},
+	{"0x00001fff", 0x00001fff, 13},
+	{"0x00002000", 0x00002000, 13},
+	{"0x50000000", 0x50000000, 31},
+	{"0x80000000", 0x80000000, 31},
+	{"0x80003000", 0x80003000, 32},
+};
+
+KUNIT_ARRAY_PARAM_DESC(order, order_test_cases, str);
+
+static void test_get_count_order(struct kunit *test)
+{
+	const struct order_test_case *params = test->param_value;
+
+	KUNIT_EXPECT_EQ(test, get_count_order(params->count), params->expected);
+	KUNIT_EXPECT_EQ(test, get_count_order_long(params->count), params->expected);
+}
+
+#ifdef CONFIG_64BIT
+struct order_long_test_case {
+	const char *str;
+	const unsigned long count;
+	const int expected;
+};
+
+static struct order_long_test_case order_long_test_cases[] = {
+	{"0x0000000300000000", 0x0000000300000000, 34},
+	{"0x0000000400000000", 0x0000000400000000, 34},
+	{"0x00001fff00000000", 0x00001fff00000000, 45},
+	{"0x0000200000000000", 0x0000200000000000, 45},
+	{"0x5000000000000000", 0x5000000000000000, 63},
+	{"0x8000000000000000", 0x8000000000000000, 63},
+	{"0x8000300000000000", 0x8000300000000000, 64},
+};
+
+KUNIT_ARRAY_PARAM_DESC(order_long, order_long_test_cases, str);
+
+static void test_get_count_order_long(struct kunit *test)
+{
+	const struct order_long_test_case *params = test->param_value;
+
+	KUNIT_EXPECT_EQ(test, get_count_order_long(params->count), params->expected);
+}
+#endif
+
+static struct kunit_case bitops_test_cases[] = {
+	KUNIT_CASE_PARAM(test_set_bit_clear_bit, bitops_gen_params),
+	KUNIT_CASE_PARAM(test_change_bit, bitops_gen_params),
+	KUNIT_CASE_PARAM(test_test_and_set_bit_test_and_clear_bit, bitops_gen_params),
+	KUNIT_CASE_PARAM(test_test_and_change_bit, bitops_gen_params),
+	KUNIT_CASE_PARAM(test_get_count_order, order_gen_params),
+#ifdef CONFIG_64BIT
+	KUNIT_CASE_PARAM(test_get_count_order_long, order_long_gen_params),
+#endif
+	{},
+};
+
+static struct kunit_suite bitops_test_suite = {
+	.name = "bitops",
+	.test_cases = bitops_test_cases,
+};
+
+kunit_test_suite(bitops_test_suite);
+
+MODULE_AUTHOR("Jesse Brandeburg <jesse.brandeburg@intel.com>");
+MODULE_AUTHOR("Wei Yang <richard.weiyang@gmail.com>");
+MODULE_AUTHOR("Ryota Sakamoto <sakamo.ryota@gmail.com>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Bit testing module");

rust/helpers/bitmap.c

@@ -2,6 +2,7 @@
 
 #include <linux/bitmap.h>
 
+__rust_helper
 void rust_helper_bitmap_copy_and_extend(unsigned long *to, const unsigned long *from,
 		unsigned int count, unsigned int size)
 {

rust/helpers/bitops.c

@@ -3,21 +3,25 @@
 #include <linux/bitops.h>
 #include <linux/find.h>
 
+__rust_helper
 void rust_helper___set_bit(unsigned long nr, unsigned long *addr)
 {
 	__set_bit(nr, addr);
 }
 
+__rust_helper
 void rust_helper___clear_bit(unsigned long nr, unsigned long *addr)
 {
 	__clear_bit(nr, addr);
 }
 
+__rust_helper
 void rust_helper_set_bit(unsigned long nr, volatile unsigned long *addr)
 {
 	set_bit(nr, addr);
 }
 
+__rust_helper
 void rust_helper_clear_bit(unsigned long nr, volatile unsigned long *addr)
 {
 	clear_bit(nr, addr);

rust/helpers/cpumask.c

@@ -2,67 +2,80 @@
 
 #include <linux/cpumask.h>
 
+__rust_helper
 void rust_helper_cpumask_set_cpu(unsigned int cpu, struct cpumask *dstp)
 {
 	cpumask_set_cpu(cpu, dstp);
 }
 
+__rust_helper
 void rust_helper___cpumask_set_cpu(unsigned int cpu, struct cpumask *dstp)
 {
 	__cpumask_set_cpu(cpu, dstp);
 }
 
+__rust_helper
 void rust_helper_cpumask_clear_cpu(int cpu, struct cpumask *dstp)
 {
 	cpumask_clear_cpu(cpu, dstp);
 }
 
+__rust_helper
 void rust_helper___cpumask_clear_cpu(int cpu, struct cpumask *dstp)
 {
 	__cpumask_clear_cpu(cpu, dstp);
 }
 
+__rust_helper
 bool rust_helper_cpumask_test_cpu(int cpu, struct cpumask *srcp)
 {
 	return cpumask_test_cpu(cpu, srcp);
 }
 
+__rust_helper
 void rust_helper_cpumask_setall(struct cpumask *dstp)
 {
 	cpumask_setall(dstp);
 }
 
+__rust_helper
 bool rust_helper_cpumask_empty(struct cpumask *srcp)
 {
 	return cpumask_empty(srcp);
 }
 
+__rust_helper
 bool rust_helper_cpumask_full(struct cpumask *srcp)
 {
 	return cpumask_full(srcp);
 }
 
+__rust_helper
 unsigned int rust_helper_cpumask_weight(struct cpumask *srcp)
 {
 	return cpumask_weight(srcp);
 }
 
+__rust_helper
 void rust_helper_cpumask_copy(struct cpumask *dstp, const struct cpumask *srcp)
 {
 	cpumask_copy(dstp, srcp);
 }
 
+__rust_helper
 bool rust_helper_alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
 {
 	return alloc_cpumask_var(mask, flags);
 }
 
+__rust_helper
 bool rust_helper_zalloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
 {
 	return zalloc_cpumask_var(mask, flags);
 }
 
 #ifndef CONFIG_CPUMASK_OFFSTACK
+__rust_helper
 void rust_helper_free_cpumask_var(cpumask_var_t mask)
 {
 	free_cpumask_var(mask);