uml: simplify helper stack handling

run_helper and run_helper_thread had arguments which were the same in all
callers.  run_helper's stack_out was always NULL and run_helper_thread's
stack_order was always 0.  These are now gone, and the constants folded
into the code.

Also fixed leaks of the helper stack in the AIO and SIGIO code.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 12 insertions, 7 deletions

diff --git a/arch/um/os-Linux/sigio.c b/arch/um/os-Linux/sigio.c
index 8d4e0c6b8c92..2c23cb261188 100644
--- a/arch/um/os-Linux/sigio.c
+++ b/arch/um/os-Linux/sigio.c
@@ -26,6 +26,7 @@
  * exitcall.
  */
 static int write_sigio_pid = -1;
+static unsigned long write_sigio_stack;
 
 /* These arrays are initialized before the sigio thread is started, and
  * the descriptors closed after it is killed.  So, it can't see them change.
@@ -144,8 +145,10 @@ static void update_thread(void)
         return;
  fail:
         /* Critical section start */
-        if(write_sigio_pid != -1)
+        if (write_sigio_pid != -1) {
                 os_kill_process(write_sigio_pid, 1);
+                free_stack(write_sigio_stack, 0);
+        }
         write_sigio_pid = -1;
         close(sigio_private[0]);
         close(sigio_private[1]);
@@ -243,7 +246,6 @@ static struct pollfd *setup_initial_poll(int fd)
 
 static void write_sigio_workaround(void)
 {
-        unsigned long stack;
         struct pollfd *p;
         int err;
         int l_write_sigio_fds[2];
@@ -293,7 +295,8 @@ static void write_sigio_workaround(void)
         memcpy(sigio_private, l_sigio_private, sizeof(l_sigio_private));
 
         write_sigio_pid = run_helper_thread(write_sigio_thread, NULL,
-                                            CLONE_FILES | CLONE_VM, &stack, 0);
+                                            CLONE_FILES | CLONE_VM,
+                                            &write_sigio_stack);
 
         if (write_sigio_pid < 0)
                 goto out_clear;
@@ -356,10 +359,12 @@ out:
 
 static void sigio_cleanup(void)
 {
-        if(write_sigio_pid != -1){
-                os_kill_process(write_sigio_pid, 1);
-                write_sigio_pid = -1;
-        }
+        if (write_sigio_pid == -1)
+                return;
+
+        os_kill_process(write_sigio_pid, 1);
+        free_stack(write_sigio_stack, 0);
+        write_sigio_pid = -1;
 }
 
 __uml_exitcall(sigio_cleanup);