[PATCH v2 6/8] lib/find_bit: Add test-module,find_last_zero_bit

[Levi Yun <ppbuk5246@gmail.com>]

Add test module to test find_last_zero_bit and
find_each_*_bit_revserse.

Signed-off-by: Levi Yun <ppbuk5246@gmail.com>
---
 lib/Kconfig.debug        |   8 ++
 lib/Makefile             |   1 +
 lib/test_find_last_bit.c | 235 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 244 insertions(+)
 create mode 100644 lib/test_find_last_bit.c

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index c789b39ed527..481e366d0e82 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2188,6 +2188,14 @@ config FIND_BIT_BENCHMARK
 
 	  If unsure, say N.
 
+config TEST_FIND_LAST_BIT
+	tristate "Test find_last_*_bit functions"
+	help
+	  This builds the "test_find_last_bit" module that measure find_last_*_bit()
+	  functions performance.
+
+	  If unsure, say N.
+
 config TEST_FIRMWARE
 	tristate "Test firmware loading via userspace interface"
 	depends on FW_LOADER
diff --git a/lib/Makefile b/lib/Makefile
index ce45af50983a..310719df6207 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -58,6 +58,7 @@ obj-y += hexdump.o
 obj-$(CONFIG_TEST_HEXDUMP) += test_hexdump.o
 obj-y += kstrtox.o
 obj-$(CONFIG_FIND_BIT_BENCHMARK) += find_bit_benchmark.o
+obj-$(CONFIG_TEST_FIND_LAST_BIT) += test_find_last_bit.o
 obj-$(CONFIG_TEST_BPF) += test_bpf.o
 obj-$(CONFIG_TEST_FIRMWARE) += test_firmware.o
 obj-$(CONFIG_TEST_BITOPS) += test_bitops.o
diff --git a/lib/test_find_last_bit.c b/lib/test_find_last_bit.c
new file mode 100644
index 000000000000..579866c476d1
--- /dev/null
+++ b/lib/test_find_last_bit.c
@@ -0,0 +1,235 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Test for find_prev_*_bit functions.
+ *
+ * Copyright (c) 2020 Levi Yun.
+ */
+
+#include <linux/bitops.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/printk.h>
+#include <linux/random.h>
+
+
+#define BITMAP_LEN		(4096UL * 8 * 10)
+#define BITMAP_LAST_IDX		BITMAP_LEN - 1
+
+
+static DECLARE_BITMAP(zero_bitmap, BITMAP_LEN) __initdata;
+static DECLARE_BITMAP(full_bitmap, BITMAP_LEN) __initdata;
+
+static int __init test_for_each_clear_rev(const void *bitmap, unsigned long len)
+{
+	unsigned long cur;
+	unsigned long expect = BITMAP_LAST_IDX;
+
+	pr_err("[%s:%d] Start test clear full iteration\n", __func__, __LINE__);
+
+	len = BITMAP_LEN;
+
+	for_each_clear_bit_reverse(cur, bitmap, len) {
+		if (cur != expect) {
+			pr_err("[%s:%d] full iteration fail!,  expect: %lu, cur: %lu\n",
+					__func__, __LINE__, expect, cur);
+
+			return 0;
+		}
+
+		expect--;
+	}
+
+	len = BITMAP_LEN;
+
+	cur = len / 3;
+	expect = cur;
+	pr_err("[%s:%d] Success\n", __func__, __LINE__);
+
+	pr_err("[%s:%d] Start test clear iteration with starting point\n", __func__, __LINE__);
+	for_each_clear_bit_from_reverse(cur, bitmap, len) {
+		if (cur != expect) {
+			pr_err("[%s:%d] full iteration fail!,  expect: %lu, cur: %lu\n",
+					__func__, __LINE__, expect, cur);
+
+			return 0;
+		}
+
+		expect--;
+	}
+
+	pr_err("[%s:%d] Success\n", __func__, __LINE__);
+
+	return 0;
+}
+
+static int __init test_for_each_set_rev(const void *bitmap, unsigned long len)
+{
+	unsigned long cur;
+	unsigned long expect = BITMAP_LAST_IDX;
+
+	len = BITMAP_LEN;
+	pr_err("[%s:%d] Start test set full iteration\n", __func__, __LINE__);
+	for_each_set_bit_reverse(cur, bitmap, len) {
+		if (cur != expect) {
+			pr_err("[%s:%d] full iteration fail!,  expect: %lu, cur: %lu\n",
+					__func__, __LINE__, expect, cur);
+
+			return 0;
+		}
+
+		expect--;
+	}
+	pr_err("[%s:%d] Success\n", __func__, __LINE__);
+
+
+	len = BITMAP_LEN;
+	cur = len / 3;
+	expect =  cur;
+
+	pr_err("[%s:%d] Start test set iteration with starting point\n", __func__, __LINE__);
+	for_each_set_bit_from_reverse(cur, bitmap, len) {
+		if (cur != expect) {
+			pr_err("[%s:%d] full iteration fail!,  expect: %lu, cur: %lu\n",
+					__func__, __LINE__, expect, cur);
+
+			return 0;
+		}
+
+		expect--;
+	}
+	pr_err("[%s:%d] Success\n", __func__, __LINE__);
+
+	return 0;
+}
+
+static int __init test_find_last_bit_clear_middle(void *bitmap)
+{
+	unsigned long idx;
+	unsigned long len = 4096;
+
+	pr_err("[%s] Start test\n", __func__);
+
+	clear_bit(1, bitmap);
+	clear_bit(65, bitmap);
+	clear_bit(136, bitmap);
+	clear_bit(4095, bitmap);
+
+	idx = find_last_zero_bit(bitmap, len);
+	if (idx != 4095) {
+		pr_err("[%s] Fail! expect: %u, idx: %lu\n", __func__, 4095, idx);
+
+		goto teardown;
+	}
+
+	idx = find_last_zero_bit(bitmap, idx);
+	if (idx != 136) {
+		pr_err("[%s] Fail! expect: %u, idx: %lu\n", __func__, 127, idx);
+
+		goto teardown;
+	}
+
+	idx = find_last_zero_bit(bitmap, idx);
+	if (idx != 65) {
+		pr_err("[%s] Fail! expect: %u, idx: %lu\n", __func__, 65, idx);
+
+		goto teardown;
+	}
+
+	idx = find_last_zero_bit(bitmap, idx);
+	if (idx != 1) {
+		pr_err("[%s] Fail! expect: %u, idx: %lu\n", __func__, 1, idx);
+
+		goto teardown;
+	}
+
+	idx = find_last_zero_bit(bitmap, idx);
+	if (idx != 1) {
+		pr_err("[%s] Fail (find no bit clear)! expect: %u, idx: %lu\n", __func__, 1, idx);
+
+		goto teardown;
+	}
+
+	pr_err("[%s] Success\n", __func__);
+
+teardown:
+	set_bit(4095, bitmap);
+	set_bit(136, bitmap);
+	set_bit(65, bitmap);
+	set_bit(1, bitmap);
+
+	return 0;
+}
+
+static int __init test_find_last_zero_bit(void *bitmap, unsigned long len)
+{
+	unsigned long idx;
+	pr_err("[%s] Start test\n", __func__);
+
+	idx = find_last_zero_bit(bitmap, len);
+	if (idx != len) {
+		pr_err("[%s] Fail! expect: %lu, idx: %lu\n", __func__, len, idx);
+
+		goto teardown;
+	}
+
+	clear_bit(4095, bitmap);
+	clear_bit(2032, bitmap);
+	clear_bit(0, bitmap);
+
+	idx = find_last_zero_bit(bitmap, len);
+	if (idx != 4095) {
+		pr_err("[%s] Fail! expect: %u, idx: %lu\n", __func__, 4095, idx);
+
+		goto teardown;
+	}
+
+	idx = find_last_zero_bit(bitmap, idx);
+	if (idx != 2032) {
+		pr_err("[%s] Fail! expect: %u, idx: %lu\n", __func__, 2032, idx);
+
+		goto teardown;
+	}
+
+	idx = find_last_zero_bit(bitmap, idx);
+	if (idx != 0) {
+		pr_err("[%s] Fail! expect: %u, idx: %lu\n", __func__, 0, idx);
+
+		goto teardown;
+	}
+
+	pr_err("[%s] Success\n", __func__);
+
+teardown:
+	set_bit(0, bitmap);
+	set_bit(2032, bitmap);
+	set_bit(4095, bitmap);
+
+	return 0;
+}
+
+static int __init find_last_bit_test(void)
+{
+	bitmap_zero(zero_bitmap, BITMAP_LEN);
+	bitmap_fill(full_bitmap, BITMAP_LEN);
+	pr_err("\nStart testing find_last_*_bit()\n");
+
+	test_for_each_clear_rev(zero_bitmap, BITMAP_LEN);
+	test_for_each_set_rev(full_bitmap, BITMAP_LEN);
+	test_find_last_bit_clear_middle(full_bitmap);
+	test_find_last_zero_bit(full_bitmap, BITMAP_LEN);
+
+	pr_err("\nFinish testing find_last_*_bit()\n");
+
+	/*
+	 * Everything is OK. Return error just to let user run benchmark
+	 * again without annoying rmmod.
+	 */
+	return -EINVAL;
+}
+
+
+module_init(find_last_bit_test);
+
+
+MODULE_LICENSE("GPL");
-- 
2.27.0