path: root/lib/kunit_iov_iter.c

// SPDX-License-Identifier: GPL-2.0-only
/* I/O iterator tests.  This can only test kernel-backed iterator types.
 *
 * Copyright (C) 2023 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/uio.h>
#include <linux/bvec.h>
#include <kunit/test.h>

MODULE_DESCRIPTION("iov_iter testing");
MODULE_AUTHOR("David Howells <dhowells@redhat.com>");
MODULE_LICENSE("GPL");

struct kvec_test_range {
	int	from, to;
};

static const struct kvec_test_range kvec_test_ranges[] = {
	{ 0x00002, 0x00002 },
	{ 0x00027, 0x03000 },
	{ 0x05193, 0x18794 },
	{ 0x20000, 0x20000 },
	{ 0x20000, 0x24000 },
	{ 0x24000, 0x27001 },
	{ 0x29000, 0xffffb },
	{ 0xffffd, 0xffffe },
	{ -1 }
};

static inline u8 pattern(unsigned long x)
{
	return x & 0xff;
}

static void iov_kunit_unmap(void *data)
{
	vunmap(data);
}

static void *__init iov_kunit_create_buffer(struct kunit *test,
					    struct page ***ppages,
					    size_t npages)
{
	struct page **pages;
	unsigned long got;
	void *buffer;

	pages = kunit_kcalloc(test, npages, sizeof(struct page *), GFP_KERNEL);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pages);
	*ppages = pages;

	got = alloc_pages_bulk_array(GFP_KERNEL, npages, pages);
	if (got != npages) {
		release_pages(pages, got);
		KUNIT_ASSERT_EQ(test, got, npages);
	}

	buffer = vmap(pages, npages, VM_MAP | VM_MAP_PUT_PAGES, PAGE_KERNEL);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, buffer);

	kunit_add_action_or_reset(test, iov_kunit_unmap, buffer);
	return buffer;
}

static void __init iov_kunit_load_kvec(struct kunit *test,
				       struct iov_iter *iter, int dir,
				       struct kvec *kvec, unsigned int kvmax,
				       void *buffer, size_t bufsize,
				       const struct kvec_test_range *pr)
{
	size_t size = 0;
	int i;

	for (i = 0; i < kvmax; i++, pr++) {
		if (pr->from < 0)
			break;
		KUNIT_ASSERT_GE(test, pr->to, pr->from);
		KUNIT_ASSERT_LE(test, pr->to, bufsize);
		kvec[i].iov_base = buffer + pr->from;
		kvec[i].iov_len = pr->to - pr->from;
		size += pr->to - pr->from;
	}
	KUNIT_ASSERT_LE(test, size, bufsize);

	iov_iter_kvec(iter, dir, kvec, i, size);
}

/*
 * Test copying to a ITER_KVEC-type iterator.
 */
static void __init iov_kunit_copy_to_kvec(struct kunit *test)
{
	const struct kvec_test_range *pr;
	struct iov_iter iter;
	struct page **spages, **bpages;
	struct kvec kvec[8];
	u8 *scratch, *buffer;
	size_t bufsize, npages, size, copied;
	int i, patt;

	bufsize = 0x100000;
	npages = bufsize / PAGE_SIZE;

	scratch = iov_kunit_create_buffer(test, &spages, npages);
	for (i = 0; i < bufsize; i++)
		scratch[i] = pattern(i);

	buffer = iov_kunit_create_buffer(test, &bpages, npages);
	memset(buffer, 0, bufsize);

	iov_kunit_load_kvec(test, &iter, READ, kvec, ARRAY_SIZE(kvec),
			    buffer, bufsize, kvec_test_ranges);
	size = iter.count;

	copied = copy_to_iter(scratch, size, &iter);

	KUNIT_EXPECT_EQ(test, copied, size);
	KUNIT_EXPECT_EQ(test, iter.count, 0);
	KUNIT_EXPECT_EQ(test, iter.nr_segs, 0);

	/* Build the expected image in the scratch buffer. */
	patt = 0;
	memset(scratch, 0, bufsize);
	for (pr = kvec_test_ranges; pr->from >= 0; pr++)
		for (i = pr->from; i < pr->to; i++)
			scratch[i] = pattern(patt++);

	/* Compare the images */
	for (i = 0; i < bufsize; i++) {
		KUNIT_EXPECT_EQ_MSG(test, buffer[i], scratch[i], "at i=%x", i);
		if (buffer[i] != scratch[i])
			return;
	}

	KUNIT_SUCCEED(test);
}

/*
 * Test copying from a ITER_KVEC-type iterator.
 */
static void __init iov_kunit_copy_from_kvec(struct kunit *test)
{
	const struct kvec_test_range *pr;
	struct iov_iter iter;
	struct page **spages, **bpages;
	struct kvec kvec[8];
	u8 *scratch, *buffer;
	size_t bufsize, npages, size, copied;
	int i,