Created a function for setting timeouts on keys

The keyctl_set_timeout function isn't exported to other parts of the
kernel, but I want to use it for the NFS idmapper.  I already have the
key, but I wanted a generic way to set the timeout.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/security/keys/key.c b/security/keys/key.c
index 7ada8019be1..06783cffb3a 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -671,6 +671,26 @@ found_kernel_type:
 	return ktype;
 }
 
+void key_set_timeout(struct key *key, unsigned timeout)
+{
+	struct timespec now;
+	time_t expiry = 0;
+
+	/* make the changes with the locks held to prevent races */
+	down_write(&key->sem);
+
+	if (timeout > 0) {
+		now = current_kernel_time();
+		expiry = now.tv_sec + timeout;
+	}
+
+	key->expiry = expiry;
+	key_schedule_gc(key->expiry + key_gc_delay);
+
+	up_write(&key->sem);
+}
+EXPORT_SYMBOL_GPL(key_set_timeout);
+
 /*
  * Unlock a key type locked by key_type_lookup().
  */