[RFC PATCH 5 6/7] KEYS - use correct memory allocation flag in call_usermodehelper_keys()

[Ian Kent <raven@themaw.net>]

From: Ian Kent <ikent@redhat.com>

When call_usermodehelper_keys() is called it assumes it won't be called
with the flag UMH_NO_WAIT. Currently that's always the case.

Change this to check the flag and use the correct kernel memory allocation
flag to guard against future changes.

Signed-off-by: Ian Kent <ikent@redhat.com>
Cc: Benjamin Coddington <bcodding@redhat.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: J. Bruce Fields <bfields@fieldses.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: Oleg Nesterov <onestero@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Jeff Layton <jeff.layton@primarydata.com>
---
 security/keys/request_key.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index 486ef6f..e865f9f 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -76,8 +76,10 @@ static int call_usermodehelper_keys(char *path, char **argv, char **envp,
 					struct key *session_keyring, int wait)
 {
 	struct subprocess_info *info;
+	unsigned int gfp_mask = (wait & UMH_NO_WAIT) ?
+					GFP_ATOMIC : GFP_KERNEL;
 
-	info = call_usermodehelper_setup(path, argv, envp, GFP_KERNEL,
+	info = call_usermodehelper_setup(path, argv, envp, gfp_mask,
 					  umh_keys_init, umh_keys_cleanup,
 					  session_keyring);
 	if (!info)