#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 *pfn_app;	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 = UINT_MAX;	struct test *test, tests[] = {		{ -EINVAL, 1, pfn(0), NULL, PAGE_SIZE, 0, 1 },		{ 0, 1, pfn(0), NULL, PAGE_SIZE, PAGE_SIZE + 1, 1 },		{ 0, 1, pfn(0), NULL, PAGE_SIZE, sgmax, 1 },		{ 0, 1, pfn(0), NULL, 1, sgmax, 1 },		{ 0, 2, pfn(0, 1), NULL, 2 * PAGE_SIZE, sgmax, 1 },		{ 0, 2, pfn(1, 0), NULL, 2 * PAGE_SIZE, sgmax, 2 },		{ 0, 3, pfn(0, 1, 2), NULL, 3 * PAGE_SIZE, sgmax, 1 },		{ 0, 3, pfn(0, 1, 2), NULL, 3 * PAGE_SIZE, sgmax, 1 },		{ 0, 3, pfn(0, 1, 2), pfn(3, 4, 5), 3 * PAGE_SIZE, sgmax, 1 },		{ 0, 3, pfn(0, 1, 2), pfn(4, 5, 6), 3 * PAGE_SIZE, sgmax, 2 },		{ 0, 3, pfn(0, 2, 1), NULL, 3 * PAGE_SIZE, sgmax, 3 },		{ 0, 3, pfn(0, 1, 3), NULL, 3 * PAGE_SIZE, sgmax, 2 },		{ 0, 3, pfn(1, 2, 4), NULL, 3 * PAGE_SIZE, sgmax, 2 },		{ 0, 3, pfn(1, 3, 4), NULL, 3 * PAGE_SIZE, sgmax, 2 },		{ 0, 4, pfn(0, 1, 3, 4), NULL, 4 * PAGE_SIZE, sgmax, 2 },		{ 0, 5, pfn(0, 1, 3, 4, 5), NULL, 5 * PAGE_SIZE, sgmax, 2 },		{ 0, 5, pfn(0, 1, 3, 4, 6), NULL, 5 * PAGE_SIZE, sgmax, 3 },		{ 0, 5, pfn(0, 1, 2, 3, 4), NULL, 5 * PAGE_SIZE, sgmax, 1 },		{ 0, 5, pfn(0, 1, 2, 3, 4), NULL, 5 * PAGE_SIZE, 2 * PAGE_SIZE,		  3 },		{ 0, 6, pfn(0, 1, 2, 3, 4, 5), NULL, 6 * PAGE_SIZE,		  2 * PAGE_SIZE, 3 },		{ 0, 6, pfn(0, 2, 3, 4, 5, 6), NULL, 6 * PAGE_SIZE,		  2 * PAGE_SIZE, 4 },		{ 0, 6, pfn(0, 1, 3, 4, 5, 6), pfn(7, 8, 9, 10, 11, 12),		  6 * PAGE_SIZE, 12 * PAGE_SIZE, 2 },		{ 0, 0, NULL, NULL, 0, 0, 0 },	};	unsigned int i; 	for (i = 0, test = tests; test->expected_segments; test++, i++) {		int left_pages = test->pfn_app ? test->num_pages : 0;		struct sg_append_table append = {};		struct page *pages[MAX_PAGES];		int ret; 		set_pages(pages, test->pfn, test->num_pages); 		if (test->pfn_app)			ret = sg_alloc_append_table_from_pages(				&append, pages, test->num_pages, 0, test->size,				test->max_seg, left_pages, GFP_KERNEL);		else			ret = sg_alloc_table_from_pages_segment(				&append.sgt, pages, test->num_pages, 0,				test->size, test->max_seg, GFP_KERNEL); 		assert(ret == test->alloc_ret); 		if (test->alloc_ret)			continue; 		if (test->pfn_app) {			set_pages(pages, test->pfn_app, test->num_pages);			ret = sg_alloc_append_table_from_pages(				&append, pages, test->num_pages, 0, test->size,				test->max_seg, 0, GFP_KERNEL); 			assert(ret == test->alloc_ret);		} 		VALIDATE(append.sgt.nents == test->expected_segments,			 &append.sgt, test);		if (!test->pfn_app)			VALIDATE(append.sgt.orig_nents ==					 test->expected_segments,				 &append.sgt, test); 		if (test->pfn_app)			sg_free_append_table(&append);		else			sg_free_table(&append.sgt);	} 	assert(i == (sizeof(tests) / sizeof(tests[0])) - 1); 	return 0;}