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, 7 insertions, 12 deletions

diff --git a/arch/um/os-Linux/helper.c b/arch/um/os-Linux/helper.c
index 97bed16bf4c7..9cf48d0577cc 100644
--- a/arch/um/os-Linux/helper.c
+++ b/arch/um/os-Linux/helper.c
@@ -44,17 +44,13 @@ static int helper_child(void *arg)
 /* Returns either the pid of the child process we run or -E* on failure.
  * XXX The alloc_stack here breaks if this is called in the tracing thread, so
  * we need to receive a preallocated stack (a local buffer is ok). */
-int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv,
-               unsigned long *stack_out)
+int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv)
 {
         struct helper_data data;
         unsigned long stack, sp;
         int pid, fds[2], ret, n;
 
-        if ((stack_out != NULL) && (*stack_out != 0))
-                stack = *stack_out;
-        else
-                stack = alloc_stack(0, __cant_sleep());
+        stack = alloc_stack(0, __cant_sleep());
         if (stack == 0)
                 return -ENOMEM;
 
@@ -113,22 +109,21 @@ out_close:
                 close(fds[1]);
         close(fds[0]);
 out_free:
-        if ((stack_out == NULL) || (*stack_out == 0))
-                free_stack(stack, 0);
+        free_stack(stack, 0);
         return ret;
 }
 
 int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags,
-                      unsigned long *stack_out, int stack_order)
+                      unsigned long *stack_out)
 {
         unsigned long stack, sp;
         int pid, status, err;
 
-        stack = alloc_stack(stack_order, __cant_sleep());
+        stack = alloc_stack(0, __cant_sleep());
         if (stack == 0)
                 return -ENOMEM;
 
-        sp = stack + (UM_KERN_PAGE_SIZE << stack_order) - sizeof(void *);
+        sp = stack + UM_KERN_PAGE_SIZE - sizeof(void *);
         pid = clone(proc, (void *) sp, flags | SIGCHLD, arg);
         if (pid < 0) {
                 err = -errno;
@@ -147,7 +142,7 @@ int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags,
                 if (!WIFEXITED(status) || (WEXITSTATUS(status) != 0))
                         printk("run_helper_thread - thread returned status "
                                "0x%x\n", status);
-                free_stack(stack, stack_order);
+                free_stack(stack, 0);
         } else
                 *stack_out = stack;
         return pid;