[PATCH] keys: discard the contents of a key on revocation

Cause the keys linked to a keyring to be unlinked from it when revoked and it
causes the data attached to a user-defined key to be discarded when revoked.

This frees up most of the quota a key occupied at that point, rather than
waiting for the key to actually be destroyed.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/keys/user-type.h b/include/keys/user-type.h
index a3dae18..c37c342 100644
--- a/include/keys/user-type.h
+++ b/include/keys/user-type.h
@@ -37,6 +37,7 @@
 extern int user_instantiate(struct key *key, const void *data, size_t datalen);
 extern int user_update(struct key *key, const void *data, size_t datalen);
 extern int user_match(const struct key *key, const void *criterion);
+extern void user_revoke(struct key *key);
 extern void user_destroy(struct key *key);
 extern void user_describe(const struct key *user, struct seq_file *m);
 extern long user_read(const struct key *key,