audit: consolidate handling of mm->exe_file

This patch adds a audit_log_d_path_exe() helper function
to share how we handle auditing of the exe_file's path.
Used by both audit and auditsc. No functionality is changed.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
[PM: tweaked subject line]
Signed-off-by: Paul Moore <pmoore@redhat.com>

kernel/auditsc.c

diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 793e9e9..4b89f7f 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -2460,7 +2460,6 @@
 	kuid_t auid, uid;
 	kgid_t gid;
 	unsigned int sessionid;
-	struct mm_struct *mm = current->mm;
 	char comm[sizeof(current->comm)];
 
 	auid = audit_get_loginuid(current);
@@ -2475,13 +2474,7 @@
 	audit_log_task_context(ab);
 	audit_log_format(ab, " pid=%d comm=", task_pid_nr(current));
 	audit_log_untrustedstring(ab, get_task_comm(comm, current));
-	if (mm) {
-		down_read(&mm->mmap_sem);
-		if (mm->exe_file)
-			audit_log_d_path(ab, " exe=", &mm->exe_file->f_path);
-		up_read(&mm->mmap_sem);
-	} else
-		audit_log_format(ab, " exe=(null)");
+	audit_log_d_path_exe(ab, current->mm);
 }
 
 /**