[LTP] [PATCH v4 5/8] Cleanup mmap18 test

[Andrea Cervesato]

From: Andrea Cervesato <andrea.cervesato@suse.com>

Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>
---
 testcases/kernel/syscalls/mmap/mmap18.c | 90 ++++++++++++++++-----------------
 1 file changed, 43 insertions(+), 47 deletions(-)

diff --git a/testcases/kernel/syscalls/mmap/mmap18.c b/testcases/kernel/syscalls/mmap/mmap18.c
index b37b29890ca009ea671b29e81e02fc1e42b44dbb..3de524ecc60b53ec352f58a00620dc39f3f787a5 100644
--- a/testcases/kernel/syscalls/mmap/mmap18.c
+++ b/testcases/kernel/syscalls/mmap/mmap18.c
@@ -1,58 +1,54 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Copyright (c) Zilogic Systems Pvt. Ltd., 2020
- * Email: code@zilogic.com
+ *	Email: code@zilogic.com
+ * Copyright (C) 2025 SUSE LLC Andrea Cervesato <andrea.cervesato@suse.com>
  */
 
-/*
- * Test mmap() MAP_GROWSDOWN flag
+/*\
+ * Verify mmap() syscall using MAP_GROWSDOWN flag.
+ *
+ * [Algorithm]
  *
- * # Test1:
+ * **Test 1**
  *
- *   We assign the memory region partially allocated with MAP_GROWSDOWN flag to
- *   a thread as a stack and expect the mapping to grow when we touch the
- *   guard page by calling a recusive function in the thread that uses the
- *   growable mapping as a stack.
+ * We assign the memory region partially allocated with MAP_GROWSDOWN flag to
+ * a thread as a stack and expect the mapping to grow when we touch the
+ * guard page by calling a recusive function in the thread that uses the
+ * growable mapping as a stack.
  *
- *   The kernel only grows the memory region when the stack pointer is within
- *   guard page when the guard page is touched so simply faulting the guard
- *   page will not cause the mapping to grow.
+ * The kernel only grows the memory region when the stack pointer is within
+ * guard page when the guard page is touched so simply faulting the guard
+ * page will not cause the mapping to grow.
  *
- *   Newer kernels does not allow a MAP_GROWSDOWN mapping to grow closer than
- *   'stack_guard_gap' pages to an existing mapping. So when we map the stack we
- *   make sure there is enough of free address space before the lowest stack
- *   address.
+ * Newer kernels does not allow a MAP_GROWSDOWN mapping to grow closer than
+ * 'stack_guard_gap' pages to an existing mapping. So when we map the stack we
+ * make sure there is enough of free address space before the lowest stack
+ * address.
  *
- *   Kernel default 'stack_guard_gap' size is '256 * getpagesize()'.
+ * Kernel default `stack_guard_gap` size is `256 * getpagesize()`.
  *
- *   The stack memory map would look like:
+ * The stack memory map would look like:
  *
- *   |  -  -  -   reserved  size   -  -  -  |
+ * |  -  -  -   reserved  size   -  -  -  |
  *
- *   +-- - - - --+------------+-------------+
- *   | 256 pages |  unmapped  |   mapped    |
- *   +-- - - - --+------------+-------------+
- *                            | mapped size |
- *   ^           |  -  -  stack size  -  -  |
- *   start
- *               ^                          ^
- *               stack bottom       stack top
+ * +-- - - - --+------------+-------------+
+ * | 256 pages |  unmapped  |   mapped    |
+ * +-- - - - --+------------+-------------+
+ *                          | mapped size |
+ * ^           |  -  -  stack size  -  -  |
+ * start
+ *             ^                          ^
+ *             stack bottom       stack top
  *
- * # Test2:
+ * **Test 2**
  *
- *   We allocate stack as we do in the first test but we mmap a page in the
- *   space the stack is supposed to grow into and we expect the thread to
- *   segfault when the guard page is faulted.
+ * We allocate stack as we do in the first test but we mmap a page in the
+ * space the stack is supposed to grow into and we expect the thread to
+ * segfault when the guard page is faulted.
  */
 
-#include <unistd.h>
 #include <pthread.h>
-#include <sys/mman.h>
-#include <sys/wait.h>
-#include <sys/types.h>
-#include <stdlib.h>
-#include <stdbool.h>
-
 #include "tst_test.h"
 #include "tst_safe_pthread.h"
 
@@ -63,12 +59,12 @@ static bool __attribute__((noinline)) check_stackgrow_up(void)
 	char local_var;
 	static char *addr;
 
-       if (!addr) {
-               addr = &local_var;
-               return check_stackgrow_up();
-       }
+	if (!addr) {
+		addr = &local_var;
+		return check_stackgrow_up();
+	}
 
-       return (addr < &local_var);
+	return (addr < &local_var);
 }
 
 static void setup(void)
@@ -90,7 +86,7 @@ static void *allocate_stack(size_t stack_size, size_t mapped_size)
 	long reserved_size = 256 * page_size + stack_size;
 
 	start = SAFE_MMAP(NULL, reserved_size, PROT_READ | PROT_WRITE,
-	                  MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+			MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 	SAFE_MUNMAP(start, reserved_size);
 
 	SAFE_MMAP((start + reserved_size - mapped_size), mapped_size, PROT_READ | PROT_WRITE,
@@ -103,7 +99,7 @@ static void *allocate_stack(size_t stack_size, size_t mapped_size)
 	tst_res(TINFO, "start = %p, stack_top = %p, stack bottom = %p",
 		start, stack_top, stack_bottom);
 	tst_res(TINFO, "mapped pages %zu, stack pages %zu",
-	        mapped_size/page_size, stack_size/page_size);
+		mapped_size/page_size, stack_size/page_size);
 
 	return stack_bottom;
 }
@@ -192,10 +188,10 @@ static void grow_stack_fail(size_t stack_size, size_t mapped_size)
 	}
 
 	SAFE_WAIT(&wstatus);
-        if (WIFSIGNALED(wstatus) && WTERMSIG(wstatus) == SIGSEGV)
+	if (WIFSIGNALED(wstatus) && WTERMSIG(wstatus) == SIGSEGV)
 		tst_res(TPASS, "Child killed by %s as expected", tst_strsig(SIGSEGV));
-        else
-                tst_res(TFAIL, "Child: %s", tst_strstatus(wstatus));
+	else
+		tst_res(TFAIL, "Child: %s", tst_strstatus(wstatus));
 }
 
 static void run_test(void)

-- 
2.43.0