iov_iter: Kunit tests for page extraction

Add some kunit tests for page extraction for ITER_BVEC, ITER_KVEC and
ITER_XARRAY type iterators.  ITER_UBUF and ITER_IOVEC aren't dealt with
as they require userspace VM interaction.  ITER_DISCARD isn't dealt with
either as that can't be extracted.
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: David Hildenbrand <david@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/kunit_iov_iter.c

@@ -519,6 +519,243 @@ static void __init iov_kunit_copy_from_xarray(struct kunit *test)
 	KUNIT_SUCCEED();
 }
 
+/*
+ * Test the extraction of ITER_KVEC-type iterators.
+ */
+static void __init iov_kunit_extract_pages_kvec(struct kunit *test)
+{
+	const struct kvec_test_range *pr;
+	struct iov_iter iter;
+	struct page **bpages, *pagelist[8], **pages = pagelist;
+	struct kvec kvec[8];
+	u8 *buffer;
+	ssize_t len;
+	size_t bufsize, size = 0, npages;
+	int i, from;
+
+	bufsize = 0x100000;
+	npages = bufsize / PAGE_SIZE;
+
+	buffer = iov_kunit_create_buffer(test, &bpages, npages);
+
+	iov_kunit_load_kvec(test, &iter, READ, kvec, ARRAY_SIZE(kvec),
+			    buffer, bufsize, kvec_test_ranges);
+	size = iter.count;
+
+	pr = kvec_test_ranges;
+	from = pr->from;
+	do {
+		size_t offset0 = LONG_MAX;
+
+		for (i = 0; i < ARRAY_SIZE(pagelist); i++)
+			pagelist[i] = (void *)(unsigned long)0xaa55aa55aa55aa55ULL;
+
+		len = iov_iter_extract_pages(&iter, &pages, 100 * 1024,
+					     ARRAY_SIZE(pagelist), 0, &offset0);
+		KUNIT_EXPECT_GE(test, len, 0);
+		if (len < 0)
+			break;
+		KUNIT_EXPECT_GE(test, (ssize_t)offset0, 0);
+		KUNIT_EXPECT_LT(test, offset0, PAGE_SIZE);
+		KUNIT_EXPECT_LE(test, len, size);
+		KUNIT_EXPECT_EQ(test, iter.count, size - len);
+		size -= len;
+
+		if (len == 0)
+			break;
+
+		for (i = 0; i < ARRAY_SIZE(pagelist); i++) {
+			struct page *p;
+			ssize_t part = min_t(ssize_t, len, PAGE_SIZE - offset0);
+			int ix;
+
+			KUNIT_ASSERT_GE(test, part, 0);
+			while (from == pr->to) {
+				pr++;
+				from = pr->from;
+				if (from < 0)
+					goto stop;
+			}
+			ix = from / PAGE_SIZE;
+			KUNIT_ASSERT_LT(test, ix, npages);
+			p = bpages[ix];
+			KUNIT_EXPECT_PTR_EQ(test, pagelist[i], p);
+			KUNIT_EXPECT_EQ(test, offset0, from % PAGE_SIZE);
+			from += part;
+			len -= part;
+			KUNIT_ASSERT_GE(test, len, 0);
+			if (len == 0)
+				break;
+			offset0 = 0;
+		}
+
+		if (test->status == KUNIT_FAILURE)
+			break;
+	} while (iov_iter_count(&iter) > 0);
+
+stop:
+	KUNIT_EXPECT_EQ(test, size, 0);
+	KUNIT_EXPECT_EQ(test, iter.count, 0);
+	KUNIT_SUCCEED();
+}
+
+/*
+ * Test the extraction of ITER_BVEC-type iterators.
+ */
+static void __init iov_kunit_extract_pages_bvec(struct kunit *test)
+{
+	const struct bvec_test_range *pr;
+	struct iov_iter iter;
+	struct page **bpages, *pagelist[8], **pages = pagelist;
+	struct bio_vec bvec[8];
+	ssize_t len;
+	size_t bufsize, size = 0, npages;
+	int i, from;
+
+	bufsize = 0x100000;
+	npages = bufsize / PAGE_SIZE;
+
+	iov_kunit_create_buffer(test, &bpages, npages);
+	iov_kunit_load_bvec(test, &iter, READ, bvec, ARRAY_SIZE(bvec),
+			    bpages, npages, bufsize, bvec_test_ranges);
+	size = iter.count;
+
+	pr = bvec_test_ranges;
+	from = pr->from;
+	do {
+		size_t offset0 = LONG_MAX;
+
+		for (i = 0; i < ARRAY_SIZE(pagelist); i++)
+			pagelist[i] = (void *)(unsigned long)0xaa55aa55aa55aa55ULL;
+
+		len = iov_iter_extract_pages(&iter, &pages, 100 * 1024,
+					     ARRAY_SIZE(pagelist), 0, &offset0);
+		KUNIT_EXPECT_GE(test, len, 0);
+		if (len < 0)
+			break;
+		KUNIT_EXPECT_GE(test, (ssize_t)offset0, 0);
+		KUNIT_EXPECT_LT(test, offset0, PAGE_SIZE);
+		KUNIT_EXPECT_LE(test, len, size);
+		KUNIT_EXPECT_EQ(test, iter.count, size - len);
+		size -= len;
+
+		if (len == 0)
+			break;
+
+		for (i = 0; i < ARRAY_SIZE(pagelist); i++) {
+			struct page *p;
+			ssize_t part = min_t(ssize_t, len, PAGE_SIZE - offset0);
+			int ix;
+
+			KUNIT_ASSERT_GE(test, part, 0);
+			while (from == pr->to) {
+				pr++;
+				from = pr->from;
+				if (from < 0)
+					goto stop;
+			}
+			ix = pr->page + from / PAGE_SIZE;
+			KUNIT_ASSERT_LT(test, ix, npages);
+			p = bpages[ix];
+			KUNIT_EXPECT_PTR_EQ(test, pagelist[i], p);
+			KUNIT_EXPECT_EQ(test, offset0, from % PAGE_SIZE);
+			from += part;
+			len -= part;
+			KUNIT_ASSERT_GE(test, len, 0);
+			if (len == 0)
+				break;
+			offset0 = 0;
+		}
+
+		if (test->status == KUNIT_FAILURE)
+			break;
+	} while (iov_iter_count(&iter) > 0);
+
+stop:
+	KUNIT_EXPECT_EQ(test, size, 0);
+	KUNIT_EXPECT_EQ(test, iter.count, 0);
+	KUNIT_SUCCEED();
+}
+
+/*
+ * Test the extraction of ITER_XARRAY-type iterators.
+ */
+static void __init iov_kunit_extract_pages_xarray(struct kunit *test)
+{
+	const struct kvec_test_range *pr;
+	struct iov_iter iter;
+	struct xarray *xarray;
+	struct page **bpages, *pagelist[8], **pages = pagelist;
+	ssize_t len;
+	size_t bufsize, size = 0, npages;
+	int i, from;
+
+	bufsize = 0x100000;
+	npages = bufsize / PAGE_SIZE;
+
+	xarray = iov_kunit_create_xarray(test);
+
+	iov_kunit_create_buffer(test, &bpages, npages);
+	iov_kunit_load_xarray(test, &iter, READ, xarray, bpages, npages);
+
+	for (pr = kvec_test_ranges; pr->from >= 0; pr++) {
+		from = pr->from;
+		size = pr->to - from;
+		KUNIT_ASSERT_LE(test, pr->to, bufsize);
+
+		iov_iter_xarray(&iter, WRITE, xarray, from, size);
+
+		do {
+			size_t offset0 = LONG_MAX;
+
+			for (i = 0; i < ARRAY_SIZE(pagelist); i++)
+				pagelist[i] = (void *)(unsigned long)0xaa55aa55aa55aa55ULL;
+
+			len = iov_iter_extract_pages(&iter, &pages, 100 * 1024,
+						     ARRAY_SIZE(pagelist), 0, &offset0);
+			KUNIT_EXPECT_GE(test, len, 0);
+			if (len < 0)
+				break;
+			KUNIT_EXPECT_LE(test, len, size);
+			KUNIT_EXPECT_EQ(test, iter.count, size - len);
+			if (len == 0)
+				break;
+			size -= len;
+			KUNIT_EXPECT_GE(test, (ssize_t)offset0, 0);
+			KUNIT_EXPECT_LT(test, offset0, PAGE_SIZE);
+
+			for (i = 0; i < ARRAY_SIZE(pagelist); i++) {
+				struct page *p;
+				ssize_t part = min_t(ssize_t, len, PAGE_SIZE - offset0);
+				int ix;
+
+				KUNIT_ASSERT_GE(test, part, 0);
+				ix = from / PAGE_SIZE;
+				KUNIT_ASSERT_LT(test, ix, npages);
+				p = bpages[ix];
+				KUNIT_EXPECT_PTR_EQ(test, pagelist[i], p);
+				KUNIT_EXPECT_EQ(test, offset0, from % PAGE_SIZE);
+				from += part;
+				len -= part;
+				KUNIT_ASSERT_GE(test, len, 0);
+				if (len == 0)
+					break;
+				offset0 = 0;
+			}
+
+			if (test->status == KUNIT_FAILURE)
+				goto stop;
+		} while (iov_iter_count(&iter) > 0);
+
+		KUNIT_EXPECT_EQ(test, size, 0);
+		KUNIT_EXPECT_EQ(test, iter.count, 0);
+		KUNIT_EXPECT_EQ(test, iter.iov_offset, pr->to - pr->from);
+	}
+
+stop:
+	KUNIT_SUCCEED();
+}
+
 static struct kunit_case __refdata iov_kunit_cases[] = {
 	KUNIT_CASE(iov_kunit_copy_to_kvec),
 	KUNIT_CASE(iov_kunit_copy_from_kvec),
@@ -526,6 +763,9 @@ static struct kunit_case __refdata iov_kunit_cases[] = {
 	KUNIT_CASE(iov_kunit_copy_from_bvec),
 	KUNIT_CASE(iov_kunit_copy_to_xarray),
 	KUNIT_CASE(iov_kunit_copy_from_xarray),
+	KUNIT_CASE(iov_kunit_extract_pages_kvec),
+	KUNIT_CASE(iov_kunit_extract_pages_bvec),
+	KUNIT_CASE(iov_kunit_extract_pages_xarray),
 	{}
 };