// SPDX-License-Identifier: GPL-2.0
/*
 * Test cases for memcat_p() in lib/memcat_p.c
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/string.h>
#include <linux/slab.h>
#include <linux/module.h>

struct test_struct {
        int             num;
        unsigned int    magic;
};

#define MAGIC           0xf00ff00f
/* Size of each of the NULL-terminated input arrays */
#define INPUT_MAX       128
/* Expected number of non-NULL elements in the output array */
#define EXPECT          (INPUT_MAX * 2 - 2)

static int __init test_memcat_p_init(void)
{
        struct test_struct **in0, **in1, **out, **p;
        int err = -ENOMEM, i, r, total = 0;

        in0 = kzalloc_objs(*in0, INPUT_MAX);
        if (!in0)
                return err;

        in1 = kzalloc_objs(*in1, INPUT_MAX);
        if (!in1)
                goto err_free_in0;

        for (i = 0, r = 1; i < INPUT_MAX - 1; i++) {
                in0[i] = kmalloc_obj(**in0);
                if (!in0[i])
                        goto err_free_elements;

                in1[i] = kmalloc_obj(**in1);
                if (!in1[i]) {
                        kfree(in0[i]);
                        goto err_free_elements;
                }

                /* lifted from test_sort.c */
                r = (r * 725861) % 6599;
                in0[i]->num = r;
                in1[i]->num = -r;
                in0[i]->magic = MAGIC;
                in1[i]->magic = MAGIC;
        }

        in0[i] = in1[i] = NULL;

        out = memcat_p(in0, in1);
        if (!out)
                goto err_free_all_elements;

        err = -EINVAL;
        for (i = 0, p = out; *p && (i < INPUT_MAX * 2 - 1); p++, i++) {
                total += (*p)->num;

                if ((*p)->magic != MAGIC) {
                        pr_err("test failed: wrong magic at %d: %u\n", i,
                               (*p)->magic);
                        goto err_free_out;
                }
        }

        if (total) {
                pr_err("test failed: expected zero total, got %d\n", total);
                goto err_free_out;
        }

        if (i != EXPECT) {
                pr_err("test failed: expected output size %d, got %d\n",
                       EXPECT, i);
                goto err_free_out;
        }

        for (i = 0; i < INPUT_MAX - 1; i++)
                if (out[i] != in0[i] || out[i + INPUT_MAX - 1] != in1[i]) {
                        pr_err("test failed: wrong element order at %d\n", i);
                        goto err_free_out;
                }

        err = 0;
        pr_info("test passed\n");

err_free_out:
        kfree(out);
err_free_all_elements:
        i = INPUT_MAX;
err_free_elements:
        for (i--; i >= 0; i--) {
                kfree(in1[i]);
                kfree(in0[i]);
        }

        kfree(in1);
err_free_in0:
        kfree(in0);

        return err;
}

static void __exit test_memcat_p_exit(void)
{
}

module_init(test_memcat_p_init);
module_exit(test_memcat_p_exit);

MODULE_DESCRIPTION("Test cases for memcat_p() in lib/memcat_p.c");
MODULE_LICENSE("GPL");