drm/rockchip: dw_hdmi: add power domain control

[firefly-linux-kernel-4.4.55.git] / kernel / fork.c

diff --git a/kernel/fork.c b/kernel/fork.c
index d6a6da547e415427603294f41827215b71c56c20..c85efa77e82528c4ea55aae0e3ccff1836c1fab8 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -585,7 +585,8 @@ static void mm_init_owner(struct mm_struct *mm, struct task_struct *p)
 #endif
 }
 
-static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p)
+static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p,
+       struct user_namespace *user_ns)
 {
        mm->mmap = NULL;
        mm->mm_rb = RB_ROOT;
@@ -625,6 +626,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p)
        if (init_new_context(p, mm))
                goto fail_nocontext;
 
+       mm->user_ns = get_user_ns(user_ns);
        return mm;
 
 fail_nocontext:
@@ -670,7 +672,7 @@ struct mm_struct *mm_alloc(void)
                return NULL;
 
        memset(mm, 0, sizeof(*mm));
-       return mm_init(mm, current);
+       return mm_init(mm, current, current_user_ns());
 }
 
 /*
@@ -685,6 +687,7 @@ void __mmdrop(struct mm_struct *mm)
        destroy_context(mm);
        mmu_notifier_mm_destroy(mm);
        check_mm(mm);
+       put_user_ns(mm->user_ns);
        free_mm(mm);
 }
 EXPORT_SYMBOL_GPL(__mmdrop);
@@ -763,6 +766,29 @@ struct file *get_mm_exe_file(struct mm_struct *mm)
 }
 EXPORT_SYMBOL(get_mm_exe_file);
 
+/**
+ * get_task_exe_file - acquire a reference to the task's executable file
+ *
+ * Returns %NULL if task's mm (if any) has no associated executable file or
+ * this is a kernel thread with borrowed mm (see the comment above get_task_mm).
+ * User must release file via fput().
+ */
+struct file *get_task_exe_file(struct task_struct *task)
+{
+       struct file *exe_file = NULL;
+       struct mm_struct *mm;
+
+       task_lock(task);
+       mm = task->mm;
+       if (mm) {
+               if (!(task->flags & PF_KTHREAD))
+                       exe_file = get_mm_exe_file(mm);
+       }
+       task_unlock(task);
+       return exe_file;
+}
+EXPORT_SYMBOL(get_task_exe_file);
+
 /**
  * get_task_mm - acquire a reference to the task's mm
  *
@@ -879,14 +905,12 @@ void mm_release(struct task_struct *tsk, struct mm_struct *mm)
        deactivate_mm(tsk, mm);
 
        /*
-        * If we're exiting normally, clear a user-space tid field if
-        * requested.  We leave this alone when dying by signal, to leave
-        * the value intact in a core dump, and to save the unnecessary
-        * trouble, say, a killed vfork parent shouldn't touch this mm.
-        * Userland only wants this done for a sys_exit.
+        * Signal userspace if we're not exiting with a core dump
+        * because we want to leave the value intact for debugging
+        * purposes.
         */
        if (tsk->clear_child_tid) {
-               if (!(tsk->flags & PF_SIGNALED) &&
+               if (!(tsk->signal->flags & SIGNAL_GROUP_COREDUMP) &&
                    atomic_read(&mm->mm_users) > 1) {
                        /*
                         * We don't check the error code - if userspace has
@@ -922,7 +946,7 @@ static struct mm_struct *dup_mm(struct task_struct *tsk)
 
        memcpy(mm, oldmm, sizeof(*mm));
 
-       if (!mm_init(mm, tsk))
+       if (!mm_init(mm, tsk, mm->user_ns))
                goto fail_nomem;
 
        err = dup_mmap(mm, oldmm);