lib/test_vmalloc.c: add vm_map_ram()/vm_unmap_ram() test case

Add vm_map_ram()/vm_unmap_ram() test case to our stress test-suite.

[akpm@linux-foundation.org: fix whitespace, per Lorenzo]
Link: https://lkml.kernel.org/r/20230330190639.431589-2-urezki@gmail.comSigned-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

lib/test_vmalloc.c

@@ -53,6 +53,7 @@ __param(int, run_test_mask, INT_MAX,
 		"\t\tid: 128,  name: pcpu_alloc_test\n"
 		"\t\tid: 256,  name: kvfree_rcu_1_arg_vmalloc_test\n"
 		"\t\tid: 512,  name: kvfree_rcu_2_arg_vmalloc_test\n"
+		"\t\tid: 1024, name: vm_map_ram_test\n"
 		/* Add a new test case description here. */
 );
 
@@ -358,6 +359,41 @@ kvfree_rcu_2_arg_vmalloc_test(void)
 	return 0;
 }
 
+static int
+vm_map_ram_test(void)
+{
+	unsigned long nr_allocated;
+	unsigned int map_nr_pages;
+	unsigned char *v_ptr;
+	struct page **pages;
+	int i;
+
+	map_nr_pages = nr_pages > 0 ? nr_pages:1;
+	pages = kmalloc(map_nr_pages * sizeof(struct page), GFP_KERNEL);
+	if (!pages)
+		return -1;
+
+	nr_allocated = alloc_pages_bulk_array(GFP_KERNEL, map_nr_pages, pages);
+	if (nr_allocated != map_nr_pages)
+		goto cleanup;
+
+	/* Run the test loop. */
+	for (i = 0; i < test_loop_count; i++) {
+		v_ptr = vm_map_ram(pages, map_nr_pages, NUMA_NO_NODE);
+		*v_ptr = 'a';
+		vm_unmap_ram(v_ptr, map_nr_pages);
+	}
+
+cleanup:
+	for (i = 0; i < nr_allocated; i++)
+		__free_page(pages[i]);
+
+	kfree(pages);
+
+	/* 0 indicates success. */
+	return nr_allocated != map_nr_pages;
+}
+
 struct test_case_desc {
 	const char *test_name;
 	int (*test_func)(void);
@@ -374,6 +410,7 @@ static struct test_case_desc test_case_array[] = {
 	{ "pcpu_alloc_test", pcpu_alloc_test },
 	{ "kvfree_rcu_1_arg_vmalloc_test", kvfree_rcu_1_arg_vmalloc_test },
 	{ "kvfree_rcu_2_arg_vmalloc_test", kvfree_rcu_2_arg_vmalloc_test },
+	{ "vm_map_ram_test", vm_map_ram_test },
 	/* Add a new test case here. */
 };