keys: Change keyring_serialise_link_sem to a mutex

Change keyring_serialise_link_sem to a mutex as it's only ever
write-locked.

Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
David Howells 2019-05-30 11:40:24 +01:00
parent 9fd165379e
commit 3be59f7451

View File

@ -100,7 +100,7 @@ EXPORT_SYMBOL(key_type_keyring);
* Semaphore to serialise link/link calls to prevent two link calls in parallel
* introducing a cycle.
*/
static DECLARE_RWSEM(keyring_serialise_link_sem);
static DEFINE_MUTEX(keyring_serialise_link_lock);
/*
* Publish the name of a keyring so that it can be found by name (if it has
@ -1206,7 +1206,7 @@ int __key_link_begin(struct key *keyring,
const struct keyring_index_key *index_key,
struct assoc_array_edit **_edit)
__acquires(&keyring->sem)
__acquires(&keyring_serialise_link_sem)
__acquires(&keyring_serialise_link_lock)
{
struct assoc_array_edit *edit;
int ret;
@ -1228,7 +1228,7 @@ int __key_link_begin(struct key *keyring,
/* serialise link/link calls to prevent parallel calls causing a cycle
* when linking two keyring in opposite orders */
if (index_key->type == &key_type_keyring)
down_write(&keyring_serialise_link_sem);
mutex_lock(&keyring_serialise_link_lock);
/* Create an edit script that will insert/replace the key in the
* keyring tree.
@ -1260,7 +1260,7 @@ int __key_link_begin(struct key *keyring,
assoc_array_cancel_edit(edit);
error_sem:
if (index_key->type == &key_type_keyring)
up_write(&keyring_serialise_link_sem);
mutex_unlock(&keyring_serialise_link_lock);
error_krsem:
up_write(&keyring->sem);
kleave(" = %d", ret);
@ -1307,13 +1307,13 @@ void __key_link_end(struct key *keyring,
const struct keyring_index_key *index_key,
struct assoc_array_edit *edit)
__releases(&keyring->sem)
__releases(&keyring_serialise_link_sem)
__releases(&keyring_serialise_link_lock)
{
BUG_ON(index_key->type == NULL);
kenter("%d,%s,", keyring->serial, index_key->type->name);
if (index_key->type == &key_type_keyring)
up_write(&keyring_serialise_link_sem);
mutex_unlock(&keyring_serialise_link_lock);
if (edit) {
if (!edit->dead_leaf) {