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Bluetooth: Convert LTK list to RCU
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This patch set converts the hdev->long_term_keys list to use RCU to
eliminate the need to use hci_dev_lock/unlock.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
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Johan Hedberg authored and Marcel Holtmann committed Nov 15, 2014
1 parent 3e64b7b commit 970d0f1
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Showing 4 changed files with 31 additions and 26 deletions.
1 change: 1 addition & 0 deletions include/net/bluetooth/hci_core.h
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Original file line number Diff line number Diff line change
Expand Up @@ -108,6 +108,7 @@ struct smp_csrk {

struct smp_ltk {
struct list_head list;
struct rcu_head rcu;
bdaddr_t bdaddr;
u8 bdaddr_type;
u8 authenticated;
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42 changes: 24 additions & 18 deletions net/bluetooth/hci_core.c
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Original file line number Diff line number Diff line change
Expand Up @@ -778,17 +778,15 @@ static const struct file_operations identity_resolving_keys_fops = {
static int long_term_keys_show(struct seq_file *f, void *ptr)
{
struct hci_dev *hdev = f->private;
struct list_head *p, *n;
struct smp_ltk *ltk;

hci_dev_lock(hdev);
list_for_each_safe(p, n, &hdev->long_term_keys) {
struct smp_ltk *ltk = list_entry(p, struct smp_ltk, list);
rcu_read_lock();
list_for_each_entry_rcu(ltk, &hdev->long_term_keys, list)
seq_printf(f, "%pMR (type %u) %u 0x%02x %u %.4x %.16llx %*phN\n",
&ltk->bdaddr, ltk->bdaddr_type, ltk->authenticated,
ltk->type, ltk->enc_size, __le16_to_cpu(ltk->ediv),
__le64_to_cpu(ltk->rand), 16, ltk->val);
}
hci_dev_unlock(hdev);
rcu_read_unlock();

return 0;
}
Expand Down Expand Up @@ -3106,11 +3104,11 @@ void hci_link_keys_clear(struct hci_dev *hdev)

void hci_smp_ltks_clear(struct hci_dev *hdev)
{
struct smp_ltk *k, *tmp;
struct smp_ltk *k;

list_for_each_entry_safe(k, tmp, &hdev->long_term_keys, list) {
list_del(&k->list);
kfree(k);
list_for_each_entry_rcu(k, &hdev->long_term_keys, list) {
list_del_rcu(&k->list);
kfree_rcu(k, rcu);
}
}

Expand Down Expand Up @@ -3184,15 +3182,18 @@ struct smp_ltk *hci_find_ltk(struct hci_dev *hdev, __le16 ediv, __le64 rand,
{
struct smp_ltk *k;

list_for_each_entry(k, &hdev->long_term_keys, list) {
rcu_read_lock();
list_for_each_entry_rcu(k, &hdev->long_term_keys, list) {
if (k->ediv != ediv || k->rand != rand)
continue;

if (ltk_role(k->type) != role)
continue;

rcu_read_unlock();
return k;
}
rcu_read_unlock();

return NULL;
}
Expand All @@ -3202,11 +3203,16 @@ struct smp_ltk *hci_find_ltk_by_addr(struct hci_dev *hdev, bdaddr_t *bdaddr,
{
struct smp_ltk *k;

list_for_each_entry(k, &hdev->long_term_keys, list)
rcu_read_lock();
list_for_each_entry_rcu(k, &hdev->long_term_keys, list) {
if (addr_type == k->bdaddr_type &&
bacmp(bdaddr, &k->bdaddr) == 0 &&
ltk_role(k->type) == role)
ltk_role(k->type) == role) {
rcu_read_unlock();
return k;
}
}
rcu_read_unlock();

return NULL;
}
Expand Down Expand Up @@ -3309,7 +3315,7 @@ struct smp_ltk *hci_add_ltk(struct hci_dev *hdev, bdaddr_t *bdaddr,
key = kzalloc(sizeof(*key), GFP_KERNEL);
if (!key)
return NULL;
list_add(&key->list, &hdev->long_term_keys);
list_add_rcu(&key->list, &hdev->long_term_keys);
}

bacpy(&key->bdaddr, bdaddr);
Expand Down Expand Up @@ -3365,17 +3371,17 @@ int hci_remove_link_key(struct hci_dev *hdev, bdaddr_t *bdaddr)

int hci_remove_ltk(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 bdaddr_type)
{
struct smp_ltk *k, *tmp;
struct smp_ltk *k;
int removed = 0;

list_for_each_entry_safe(k, tmp, &hdev->long_term_keys, list) {
list_for_each_entry_rcu(k, &hdev->long_term_keys, list) {
if (bacmp(bdaddr, &k->bdaddr) || k->bdaddr_type != bdaddr_type)
continue;

BT_DBG("%s removing %pMR", hdev->name, bdaddr);

list_del(&k->list);
kfree(k);
list_del_rcu(&k->list);
kfree_rcu(k, rcu);
removed++;
}

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4 changes: 2 additions & 2 deletions net/bluetooth/hci_event.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4578,8 +4578,8 @@ static void hci_le_ltk_request_evt(struct hci_dev *hdev, struct sk_buff *skb)
*/
if (ltk->type == SMP_STK) {
set_bit(HCI_CONN_STK_ENCRYPT, &conn->flags);
list_del(&ltk->list);
kfree(ltk);
list_del_rcu(&ltk->list);
kfree_rcu(ltk, rcu);
} else {
clear_bit(HCI_CONN_STK_ENCRYPT, &conn->flags);
}
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10 changes: 4 additions & 6 deletions net/bluetooth/smp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -383,13 +383,13 @@ static void smp_chan_destroy(struct l2cap_conn *conn)
/* If pairing failed clean up any keys we might have */
if (!complete) {
if (smp->ltk) {
list_del(&smp->ltk->list);
kfree(smp->ltk);
list_del_rcu(&smp->ltk->list);
kfree_rcu(smp->ltk, rcu);
}

if (smp->slave_ltk) {
list_del(&smp->slave_ltk->list);
kfree(smp->slave_ltk);
list_del_rcu(&smp->slave_ltk->list);
kfree_rcu(smp->slave_ltk, rcu);
}

if (smp->remote_irk) {
Expand Down Expand Up @@ -1321,15 +1321,13 @@ static int smp_cmd_master_ident(struct l2cap_conn *conn, struct sk_buff *skb)

skb_pull(skb, sizeof(*rp));

hci_dev_lock(hdev);
authenticated = (hcon->sec_level == BT_SECURITY_HIGH);
ltk = hci_add_ltk(hdev, &hcon->dst, hcon->dst_type, SMP_LTK,
authenticated, smp->tk, smp->enc_key_size,
rp->ediv, rp->rand);
smp->ltk = ltk;
if (!(smp->remote_key_dist & KEY_DIST_MASK))
smp_distribute_keys(smp);
hci_dev_unlock(hdev);

return 0;
}
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