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authorMateusz Guzik <mguzik@redhat.com>2016-08-23 16:20:38 +0200
committerPaul Moore <paul@paul-moore.com>2016-08-31 16:11:20 -0400
commitcd81a9170e69e018bbaba547c1fd85a585f5697a (patch)
treeb0c11dc4cc55aba04e21f8c7352b8c516124cbdb /kernel/fork.c
parent43761473c254b45883a64441dd0bc85a42f3645c (diff)
downloadlinux-linaro-stable-cd81a9170e69e018bbaba547c1fd85a585f5697a.tar.gz
mm: introduce get_task_exe_file
For more convenient access if one has a pointer to the task. As a minor nit take advantage of the fact that only task lock + rcu are needed to safely grab ->exe_file. This saves mm refcount dance. Use the helper in proc_exe_link. Signed-off-by: Mateusz Guzik <mguzik@redhat.com> Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Acked-by: Richard Guy Briggs <rgb@redhat.com> Cc: <stable@vger.kernel.org> # 4.3.x Signed-off-by: Paul Moore <paul@paul-moore.com>
Diffstat (limited to 'kernel/fork.c')
-rw-r--r--kernel/fork.c23
1 files changed, 23 insertions, 0 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index d277e83ed3e0..42451aeb245f 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -774,6 +774,29 @@ 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
*
* Returns %NULL if the task has no mm. Checks PF_KTHREAD (meaning