From 79c743dd1e8de61c31f484c0a1b48930543044b3 Mon Sep 17 00:00:00 2001
From: Andrew Morton <akpm@linux-foundation.org>
Date: Mon, 30 Jul 2012 14:42:17 -0700
Subject: kernel/kmod.c: document call_usermodehelper_fns() a bit

This function's interface is, uh, subtle.  Attempt to apologise for it.

Cc: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 kernel/kmod.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/kernel/kmod.c b/kernel/kmod.c
index ff2c7cb86d7..2a8351516a0 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -577,6 +577,12 @@ unlock:
 	return retval;
 }
 
+/*
+ * call_usermodehelper_fns() will not run the caller-provided cleanup function
+ * if a memory allocation failure is experienced.  So the caller might need to
+ * check the call_usermodehelper_fns() return value: if it is -ENOMEM, perform
+ * the necessaary cleanup within the caller.
+ */
 int call_usermodehelper_fns(
 	char *path, char **argv, char **envp, int wait,
 	int (*init)(struct subprocess_info *info, struct cred *new),
-- 
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