coredump: turn mm->core_startup_done into the pointer to struct core_state

mm->core_startup_done points to "struct completion startup_done" allocated
on the coredump_wait()'s stack.  Introduce the new structure, core_state,
which holds this "struct completion".  This way we can add more info
visible to the threads participating in coredump without enlarging
mm_struct.

No changes in affected .o files.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 11 insertions, 6 deletions

diff --git a/fs/exec.c b/fs/exec.c
index e347e6ed1617..71734568f018 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1597,13 +1597,13 @@ static int coredump_wait(int exit_code)
 {
         struct task_struct *tsk = current;
         struct mm_struct *mm = tsk->mm;
-        struct completion startup_done;
+        struct core_state core_state;
         struct completion *vfork_done;
         int core_waiters;
 
         init_completion(&mm->core_done);
-        init_completion(&startup_done);
-        mm->core_startup_done = &startup_done;
+        init_completion(&core_state.startup);
+        mm->core_state = &core_state;
 
         core_waiters = zap_threads(tsk, mm, exit_code);
         up_write(&mm->mmap_sem);
@@ -1622,7 +1622,7 @@ static int coredump_wait(int exit_code)
         }
 
         if (core_waiters)
-                wait_for_completion(&startup_done);
+                wait_for_completion(&core_state.startup);
 fail:
         BUG_ON(mm->core_waiters);
         return core_waiters;
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 02a27ae78539..97819efd2333 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -159,6 +159,10 @@ struct vm_area_struct {
 #endif
 };
 
+struct core_state {
+        struct completion startup;
+};
+
 struct mm_struct {
         struct vm_area_struct * mmap;           /* list of VMAs */
         struct rb_root mm_rb;
@@ -220,7 +224,8 @@ struct mm_struct {
         unsigned long flags; /* Must use atomic bitops to access the bits */
 
         /* coredumping support */
-        struct completion *core_startup_done, core_done;
+        struct core_state *core_state;
+        struct completion core_done;
 
         /* aio bits */
         rwlock_t                ioctx_list_lock;        /* aio lock */
diff --git a/kernel/exit.c b/kernel/exit.c
index 28a44a2612dc..f7fa21dbced4 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -680,7 +680,7 @@ static void exit_mm(struct task_struct * tsk)
                 up_read(&mm->mmap_sem);
                 down_write(&mm->mmap_sem);
                 if (!--mm->core_waiters)
-                        complete(mm->core_startup_done);
+                        complete(&mm->core_state->startup);
                 up_write(&mm->mmap_sem);
 
                 wait_for_completion(&mm->core_done);