ceph: handle kmalloc() failure

Return ERR_PTR(-ENOMEM) if kmalloc() fails. We handle allocation
failures the same way later in the function.

Signed-off-by: Dan Carpenter <[e-mail]>
Signed-off-by: Sage Weil <[e-mail]>

fs/ceph/mds_client.c

···
 	struct ceph_mds_session *s;
 
 	s = kzalloc(sizeof(*s), GFP_NOFS);
+	if (!s)
+		return ERR_PTR(-ENOMEM);
 	s->s_mdsc = mdsc;
 	s->s_mds = mds;
 	s->s_state = CEPH_MDS_SESSION_NEW;