1 files changed, 102 insertions, 0 deletions
diff --git a/tools/testing/scatterlist/main.c b/tools/testing/scatterlist/main.c
new file mode 100644
index 000000000..f561aed7c
--- /dev/null
+++ b/tools/testing/scatterlist/main.c
@@ -0,0 +1,102 @@
+#include <stdio.h>
+#include <assert.h>
+
+#include <linux/scatterlist.h>
+
+#define MAX_PAGES (64)
+
+struct test {
+	int alloc_ret;
+	unsigned num_pages;
+	unsigned *pfn;
+	unsigned size;
+	unsigned int max_seg;
+	unsigned int expected_segments;
+};
+
+static void set_pages(struct page **pages, const unsigned *array, unsigned num)
+{
+	unsigned int i;
+
+	assert(num < MAX_PAGES);
+	for (i = 0; i < num; i++)
+		pages[i] = (struct page *)(unsigned long)
+			   ((1 + array[i]) * PAGE_SIZE);
+}
+
+#define pfn(...) (unsigned []){ __VA_ARGS__ }
+
+static void fail(struct test *test, struct sg_table *st, const char *cond)
+{
+	unsigned int i;
+
+	fprintf(stderr, "Failed on '%s'!\n\n", cond);
+
+	printf("size = %u, max segment = %u, expected nents = %u\nst->nents = %u, st->orig_nents= %u\n",
+	       test->size, test->max_seg, test->expected_segments, st->nents,
+	       st->orig_nents);
+
+	printf("%u input PFNs:", test->num_pages);
+	for (i = 0; i < test->num_pages; i++)
+		printf(" %x", test->pfn[i]);
+	printf("\n");
+
+	exit(1);
+}
+
+#define VALIDATE(cond, st, test) \
+	if (!(cond)) \
+		fail((test), (st), #cond);
+
+int main(void)
+{
+	const unsigned int sgmax = SCATTERLIST_MAX_SEGMENT;
+	struct test *test, tests[] = {
+		{ -EINVAL, 1, pfn(0), PAGE_SIZE, 0, 1 },
+		{ 0, 1, pfn(0), PAGE_SIZE, PAGE_SIZE + 1, 1 },
+		{ 0, 1, pfn(0), PAGE_SIZE, sgmax + 1, 1 },
+		{ 0, 1, pfn(0), PAGE_SIZE, sgmax, 1 },
+		{ 0, 1, pfn(0), 1, sgmax, 1 },
+		{ 0, 2, pfn(0, 1), 2 * PAGE_SIZE, sgmax, 1 },
+		{ 0, 2, pfn(1, 0), 2 * PAGE_SIZE, sgmax, 2 },
+		{ 0, 3, pfn(0, 1, 2), 3 * PAGE_SIZE, sgmax, 1 },
+		{ 0, 3, pfn(0, 2, 1), 3 * PAGE_SIZE, sgmax, 3 },
+		{ 0, 3, pfn(0, 1, 3), 3 * PAGE_SIZE, sgmax, 2 },
+		{ 0, 3, pfn(1, 2, 4), 3 * PAGE_SIZE, sgmax, 2 },
+		{ 0, 3, pfn(1, 3, 4), 3 * PAGE_SIZE, sgmax, 2 },
+		{ 0, 4, pfn(0, 1, 3, 4), 4 * PAGE_SIZE, sgmax, 2 },
+		{ 0, 5, pfn(0, 1, 3, 4, 5), 5 * PAGE_SIZE, sgmax, 2 },
+		{ 0, 5, pfn(0, 1, 3, 4, 6), 5 * PAGE_SIZE, sgmax, 3 },
+		{ 0, 5, pfn(0, 1, 2, 3, 4), 5 * PAGE_SIZE, sgmax, 1 },
+		{ 0, 5, pfn(0, 1, 2, 3, 4), 5 * PAGE_SIZE, 2 * PAGE_SIZE, 3 },
+		{ 0, 6, pfn(0, 1, 2, 3, 4, 5), 6 * PAGE_SIZE, 2 * PAGE_SIZE, 3 },
+		{ 0, 6, pfn(0, 2, 3, 4, 5, 6), 6 * PAGE_SIZE, 2 * PAGE_SIZE, 4 },
+		{ 0, 6, pfn(0, 1, 3, 4, 5, 6), 6 * PAGE_SIZE, 2 * PAGE_SIZE, 3 },
+		{ 0, 0, NULL, 0, 0, 0 },
+	};
+	unsigned int i;
+
+	for (i = 0, test = tests; test->expected_segments; test++, i++) {
+		struct page *pages[MAX_PAGES];
+		struct sg_table st;
+		struct scatterlist *sg;
+
+		set_pages(pages, test->pfn, test->num_pages);
+
+		sg = __sg_alloc_table_from_pages(&st, pages, test->num_pages, 0,
+				test->size, test->max_seg, NULL, 0, GFP_KERNEL);
+		assert(PTR_ERR_OR_ZERO(sg) == test->alloc_ret);
+
+		if (test->alloc_ret)
+			continue;
+
+		VALIDATE(st.nents == test->expected_segments, &st, test);
+		VALIDATE(st.orig_nents == test->expected_segments, &st, test);
+
+		sg_free_table(&st);
+	}
+
+	assert(i == (sizeof(tests) / sizeof(tests[0])) - 1);
+
+	return 0;
+}