From: Johan Hedberg <johan.hedberg@xxxxxxxxx>
Since the HCI device list (hci_dev_list) is mostly accessed in a
read-only fashion we can make use of RCU instead of an rwlock to make
this access more efficient. This patch does the necessary changes to use
RCU for the hci_dev_list.
Signed-off-by: Johan Hedberg <johan.hedberg@xxxxxxxxx>
---
include/net/bluetooth/hci_core.h | 1 -
net/bluetooth/a2mp.c | 8 ++++----
net/bluetooth/hci_conn.c | 6 +++---
net/bluetooth/hci_core.c | 22 +++++++++-------------
net/bluetooth/hci_sock.c | 6 +++---
net/bluetooth/l2cap_core.c | 6 +++---
net/bluetooth/mgmt.c | 20 ++++++++++----------
7 files changed, 32 insertions(+), 37 deletions(-)
diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index b52c2ef3f56d..a26421ec7d99 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -463,7 +463,6 @@ struct hci_conn_params {
extern struct list_head hci_dev_list;
extern struct list_head hci_cb_list;
-extern rwlock_t hci_dev_list_lock;
extern rwlock_t hci_cb_list_lock;
/* ----- HCI interface to upper protocols ----- */
diff --git a/net/bluetooth/a2mp.c b/net/bluetooth/a2mp.c
index 5dcade511fdb..530d5140e1be 100644
--- a/net/bluetooth/a2mp.c
+++ b/net/bluetooth/a2mp.c
@@ -145,12 +145,12 @@ static int a2mp_discover_req(struct amp_mgr *mgr, struct sk_buff *skb,
skb_pull(skb, sizeof(ext_feat));
}
- read_lock(&hci_dev_list_lock);
+ rcu_read_lock();
/* at minimum the BR/EDR needs to be listed */
num_ctrl = 1;
- list_for_each_entry(hdev, &hci_dev_list, list) {
+ list_for_each_entry_rcu(hdev, &hci_dev_list, list) {
if (hdev->dev_type == HCI_AMP)
num_ctrl++;
}
@@ -158,7 +158,7 @@ static int a2mp_discover_req(struct amp_mgr *mgr, struct sk_buff *skb,
len = num_ctrl * sizeof(struct a2mp_cl) + sizeof(*rsp);
rsp = kmalloc(len, GFP_ATOMIC);
if (!rsp) {
- read_unlock(&hci_dev_list_lock);
+ rcu_read_unlock();
return -ENOMEM;
}
@@ -167,7 +167,7 @@ static int a2mp_discover_req(struct amp_mgr *mgr, struct sk_buff *skb,
__a2mp_add_cl(mgr, rsp->cl);
- read_unlock(&hci_dev_list_lock);
+ rcu_read_unlock();
a2mp_send(mgr, A2MP_DISCOVER_RSP, hdr->ident, len, rsp);
diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index 490ee8846d9e..19cfbc825c25 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -549,9 +549,9 @@ struct hci_dev *hci_get_route(bdaddr_t *dst, bdaddr_t *src)
BT_DBG("%pMR -> %pMR", src, dst);
- read_lock(&hci_dev_list_lock);
+ rcu_read_lock();
- list_for_each_entry(d, &hci_dev_list, list) {
+ list_for_each_entry_rcu(d, &hci_dev_list, list) {
if (!test_bit(HCI_UP, &d->flags) ||
test_bit(HCI_USER_CHANNEL, &d->dev_flags) ||
d->dev_type != HCI_BREDR)
@@ -576,7 +576,7 @@ struct hci_dev *hci_get_route(bdaddr_t *dst, bdaddr_t *src)
if (hdev)
hdev = hci_dev_hold(hdev);
- read_unlock(&hci_dev_list_lock);
+ rcu_read_unlock();
return hdev;
}
EXPORT_SYMBOL(hci_get_route);
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 172041e2b15a..ae96cf9bef6d 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -45,7 +45,6 @@ static void hci_tx_work(struct work_struct *work);
/* HCI device list */
LIST_HEAD(hci_dev_list);
-DEFINE_RWLOCK(hci_dev_list_lock);
/* HCI callback list */
LIST_HEAD(hci_cb_list);
@@ -1918,14 +1917,14 @@ struct hci_dev *hci_dev_get(int index)
if (index < 0)
return NULL;
- read_lock(&hci_dev_list_lock);
- list_for_each_entry(d, &hci_dev_list, list) {
+ rcu_read_lock();
+ list_for_each_entry_rcu(d, &hci_dev_list, list) {
if (d->id == index) {
hdev = hci_dev_hold(d);
break;
}
}
- read_unlock(&hci_dev_list_lock);
+ rcu_read_unlock();
return hdev;
}
@@ -2842,8 +2841,8 @@ int hci_get_dev_list(void __user *arg)
dr = dl->dev_req;
- read_lock(&hci_dev_list_lock);
- list_for_each_entry(hdev, &hci_dev_list, list) {
+ rcu_read_lock();
+ list_for_each_entry_rcu(hdev, &hci_dev_list, list) {
unsigned long flags = hdev->flags;
/* When the auto-off is configured it means the transport
@@ -2859,7 +2858,7 @@ int hci_get_dev_list(void __user *arg)
if (++n >= dev_num)
break;
}
- read_unlock(&hci_dev_list_lock);
+ rcu_read_unlock();
dl->dev_num = n;
size = sizeof(*dl) + n * sizeof(*dr);
@@ -4058,9 +4057,7 @@ int hci_register_dev(struct hci_dev *hdev)
set_bit(HCI_BREDR_ENABLED, &hdev->dev_flags);
}
- write_lock(&hci_dev_list_lock);
- list_add(&hdev->list, &hci_dev_list);
- write_unlock(&hci_dev_list_lock);
+ list_add_rcu(&hdev->list, &hci_dev_list);
/* Devices that are marked for raw-only usage are unconfigured
* and should not be included in normal operation.
@@ -4098,9 +4095,8 @@ void hci_unregister_dev(struct hci_dev *hdev)
id = hdev->id;
- write_lock(&hci_dev_list_lock);
- list_del(&hdev->list);
- write_unlock(&hci_dev_list_lock);
+ list_del_rcu(&hdev->list);
+ synchronize_rcu();
hci_dev_do_close(hdev);
diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
index 115f149362ba..5e15fd7ff395 100644
--- a/net/bluetooth/hci_sock.c
+++ b/net/bluetooth/hci_sock.c
@@ -367,9 +367,9 @@ static void send_monitor_replay(struct sock *sk)
{
struct hci_dev *hdev;
- read_lock(&hci_dev_list_lock);
+ rcu_read_lock();
- list_for_each_entry(hdev, &hci_dev_list, list) {
+ list_for_each_entry_rcu(hdev, &hci_dev_list, list) {
struct sk_buff *skb;
skb = create_monitor_event(hdev, HCI_DEV_REG);
@@ -380,7 +380,7 @@ static void send_monitor_replay(struct sock *sk)
kfree_skb(skb);
}
- read_unlock(&hci_dev_list_lock);
+ rcu_read_unlock();
}
/* Generate internal stack event */
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 8538cb07b0c0..a0172f5868c8 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -1096,15 +1096,15 @@ static bool __amp_capable(struct l2cap_chan *chan)
if (!(conn->fixed_chan_mask & L2CAP_FC_A2MP))
return false;
- read_lock(&hci_dev_list_lock);
- list_for_each_entry(hdev, &hci_dev_list, list) {
+ rcu_read_lock();
+ list_for_each_entry_rcu(hdev, &hci_dev_list, list) {
if (hdev->amp_type != AMP_TYPE_BREDR &&
test_bit(HCI_UP, &hdev->flags)) {
amp_available = true;
break;
}
}
- read_unlock(&hci_dev_list_lock);
+ rcu_read_unlock();
if (chan->chan_policy == BT_CHANNEL_POLICY_AMP_PREFERRED)
return amp_available;
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index 7703b72653ff..d0ceeff66c81 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -367,10 +367,10 @@ static int read_index_list(struct sock *sk, struct hci_dev *hdev, void *data,
BT_DBG("sock %p", sk);
- read_lock(&hci_dev_list_lock);
+ rcu_read_lock();
count = 0;
- list_for_each_entry(d, &hci_dev_list, list) {
+ list_for_each_entry_rcu(d, &hci_dev_list, list) {
if (d->dev_type == HCI_BREDR &&
!test_bit(HCI_UNCONFIGURED, &d->dev_flags))
count++;
@@ -379,12 +379,12 @@ static int read_index_list(struct sock *sk, struct hci_dev *hdev, void *data,
rp_len = sizeof(*rp) + (2 * count);
rp = kmalloc(rp_len, GFP_ATOMIC);
if (!rp) {
- read_unlock(&hci_dev_list_lock);
+ rcu_read_unlock();
return -ENOMEM;
}
count = 0;
- list_for_each_entry(d, &hci_dev_list, list) {
+ list_for_each_entry_rcu(d, &hci_dev_list, list) {
if (test_bit(HCI_SETUP, &d->dev_flags) ||
test_bit(HCI_CONFIG, &d->dev_flags) ||
test_bit(HCI_USER_CHANNEL, &d->dev_flags))
@@ -406,7 +406,7 @@ static int read_index_list(struct sock *sk, struct hci_dev *hdev, void *data,
rp->num_controllers = cpu_to_le16(count);
rp_len = sizeof(*rp) + (2 * count);
- read_unlock(&hci_dev_list_lock);
+ rcu_read_unlock();
err = cmd_complete(sk, MGMT_INDEX_NONE, MGMT_OP_READ_INDEX_LIST, 0, rp,
rp_len);
@@ -427,10 +427,10 @@ static int read_unconf_index_list(struct sock *sk, struct hci_dev *hdev,
BT_DBG("sock %p", sk);
- read_lock(&hci_dev_list_lock);
+ rcu_read_lock();
count = 0;
- list_for_each_entry(d, &hci_dev_list, list) {
+ list_for_each_entry_rcu(d, &hci_dev_list, list) {
if (d->dev_type == HCI_BREDR &&
test_bit(HCI_UNCONFIGURED, &d->dev_flags))
count++;
@@ -439,12 +439,12 @@ static int read_unconf_index_list(struct sock *sk, struct hci_dev *hdev,
rp_len = sizeof(*rp) + (2 * count);
rp = kmalloc(rp_len, GFP_ATOMIC);
if (!rp) {
- read_unlock(&hci_dev_list_lock);
+ rcu_read_unlock();
return -ENOMEM;
}
count = 0;
- list_for_each_entry(d, &hci_dev_list, list) {
+ list_for_each_entry_rcu(d, &hci_dev_list, list) {
if (test_bit(HCI_SETUP, &d->dev_flags) ||
test_bit(HCI_CONFIG, &d->dev_flags) ||
test_bit(HCI_USER_CHANNEL, &d->dev_flags))
@@ -466,7 +466,7 @@ static int read_unconf_index_list(struct sock *sk, struct hci_dev *hdev,
rp->num_controllers = cpu_to_le16(count);
rp_len = sizeof(*rp) + (2 * count);
- read_unlock(&hci_dev_list_lock);
+ rcu_read_unlock();
err = cmd_complete(sk, MGMT_INDEX_NONE, MGMT_OP_READ_UNCONF_INDEX_LIST,
0, rp, rp_len);
--
1.9.3
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