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KEYS: keyring_serialise_link_sem is only needed for keyring->keyring links

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keyring_serialise_link_sem is only needed for keyring->keyring links as it's
used to prevent cycle detection from being avoided by parallel keyring
additions.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
This commit is contained in:
David Howells 2010-04-30 14:32:28 +01:00 committed by James Morris
parent 0ffbe2699c
commit 553d603c8f
1 changed files with 9 additions and 7 deletions
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16
security/keys/keyring.c
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@ -705,13 +705,14 @@ int __key_link(struct key *keyring, struct key *key)
if (keyring->type != &key_type_keyring) if (keyring->type != &key_type_keyring)
goto error; goto error;
/* serialise link/link calls to prevent parallel calls causing a /* do some special keyring->keyring link checks */
* cycle when applied to two keyring in opposite orders */
down_write(&keyring_serialise_link_sem);
/* check that we aren't going to create a cycle adding one keyring to
* another */
if (key->type == &key_type_keyring) { if (key->type == &key_type_keyring) {
/* serialise link/link calls to prevent parallel calls causing
* a cycle when applied to two keyring in opposite orders */
down_write(&keyring_serialise_link_sem);
/* check that we aren't going to create a cycle adding one
* keyring to another */
ret = keyring_detect_cycle(keyring, key); ret = keyring_detect_cycle(keyring, key);
if (ret < 0) if (ret < 0)
goto error2; goto error2;
@ -814,7 +815,8 @@ int __key_link(struct key *keyring, struct key *key)
done: done:
ret = 0; ret = 0;
error2: error2:
up_write(&keyring_serialise_link_sem); if (key->type == &key_type_keyring)
up_write(&keyring_serialise_link_sem);
error: error:
return ret; return ret;