Re: [RFCv2 01/20] Bluetooth: General HCI callback implementation
From: Gustavo Padovan <hidden>
Date: 2012-07-24 19:44:17
Hi Andrei, * Andrei Emeltchenko [off-list ref] [2012-07-24 16:21:42 +0300]:
quoted hunk ↗ jump to hunk
From: Andrei Emeltchenko <redacted> Add general HCI callback implementation. Can be used for executing HCI commands from A2MP protocol. Signed-off-by: Andrei Emeltchenko <redacted> --- include/net/bluetooth/hci_core.h | 21 +++++++++ net/bluetooth/hci_core.c | 88 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 109 insertions(+)diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h index 41d9439..479e4d1 100644 --- a/include/net/bluetooth/hci_core.h +++ b/include/net/bluetooth/hci_core.h@@ -124,6 +124,17 @@ struct le_scan_params { #define HCI_MAX_SHORT_NAME_LENGTH 10 +struct hci_dev; + +struct hci_cb_cmd { + struct list_head list; + u16 opcode; + u8 status; + void *opt; + void (*cb)(struct hci_dev *hdev, struct hci_cb_cmd *cmd); + void (*destructor)(struct hci_dev *hdev, struct hci_cb_cmd *cmd); +}; + #define NUM_REASSEMBLY 4 struct hci_dev { struct list_head list;@@ -236,6 +247,9 @@ struct hci_dev { struct list_head mgmt_pending; + struct mutex cb_list_lock; + struct list_head cb_list; + struct discovery_state discovery; struct hci_conn_hash conn_hash; struct list_head blacklist;@@ -1092,5 +1106,12 @@ int hci_le_scan(struct hci_dev *hdev, u8 type, u16 interval, u16 window, int hci_cancel_le_scan(struct hci_dev *hdev); u8 bdaddr_to_le(u8 bdaddr_type); +struct hci_cb_cmd *hci_find_cb(struct hci_dev *hdev, __u16 opcode); +int hci_cmd_cb(struct hci_dev *hdev, __u16 opcode, __u32 plen, void *param, + void (*cb)(struct hci_dev *hdev, struct hci_cb_cmd *cmd), + void *opt, + void (*destructor)(struct hci_dev *hdev, struct hci_cb_cmd *cmd), + gfp_t flags); +void hci_remove_cb(struct hci_dev *hdev, struct hci_cb_cmd *cmd);
_cb usually meant that the function itself is a callback, we should put better names here, maybe: hci_callback_find() hci_callback_send_cmd() hci_callback_remove()
quoted hunk ↗ jump to hunk
#endif /* __HCI_CORE_H */diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index 28bab9d..165c235 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c@@ -36,6 +36,7 @@ static void hci_rx_work(struct work_struct *work); static void hci_cmd_work(struct work_struct *work); static void hci_tx_work(struct work_struct *work); +static void hci_cb_clear(struct hci_dev *hdev); /* HCI device list */ LIST_HEAD(hci_dev_list);@@ -1645,6 +1646,7 @@ struct hci_dev *hci_alloc_dev(void) mutex_init(&hdev->lock); mutex_init(&hdev->req_lock); + mutex_init(&hdev->cb_list_lock); INIT_LIST_HEAD(&hdev->mgmt_pending); INIT_LIST_HEAD(&hdev->blacklist);@@ -1652,6 +1654,7 @@ struct hci_dev *hci_alloc_dev(void) INIT_LIST_HEAD(&hdev->link_keys); INIT_LIST_HEAD(&hdev->long_term_keys); INIT_LIST_HEAD(&hdev->remote_oob_data); + INIT_LIST_HEAD(&hdev->cb_list); INIT_WORK(&hdev->rx_work, hci_rx_work); INIT_WORK(&hdev->cmd_work, hci_cmd_work);@@ -1817,6 +1820,7 @@ void hci_unregister_dev(struct hci_dev *hdev) hci_link_keys_clear(hdev); hci_smp_ltks_clear(hdev); hci_remote_oob_data_clear(hdev); + hci_cb_clear(hdev); hci_dev_unlock(hdev); hci_dev_put(hdev);@@ -2118,6 +2122,90 @@ int hci_send_cmd(struct hci_dev *hdev, __u16 opcode, __u32 plen, void *param) return 0; } +static int hci_add_cb(struct hci_dev *hdev, __u16 opcode, + void (*cb)(struct hci_dev *hdev, struct hci_cb_cmd *cmd), + void *opt, + void (*destructor)(struct hci_dev *hdev, + struct hci_cb_cmd *cmd), + gfp_t flags)
Then this on could be named hci_callback_add
+{
+ struct hci_cb_cmd *cmd;
+
+ cmd = kmalloc(sizeof(*cmd), flags);
+ if (!cmd)
+ return -ENOMEM;
+
+ cmd->cb = cb;
+ cmd->opcode = opcode;
+ cmd->opt = opt;
+ cmd->status = 0;
+ cmd->destructor = destructor;
+
+ mutex_lock(&hdev->cb_list_lock);
+ list_add(&cmd->list, &hdev->cb_list);
+ mutex_unlock(&hdev->cb_list_lock);can't we do RCU here, of it is not possible spinlocks? Transverse a list is a kind fast operation, we don't wanna pay two context switches here. It is expensive I think.
+
+ return 0;
+}
+
+struct hci_cb_cmd *hci_find_cb(struct hci_dev *hdev, __u16 opcode)
+{
+ struct hci_cb_cmd *cmd;
+
+ mutex_lock(&hdev->cb_list_lock);
+ list_for_each_entry(cmd, &hdev->cb_list, list)
+ if (cmd->opcode == opcode) {
+ mutex_unlock(&hdev->cb_list_lock);
+ return cmd;
+ }
+ mutex_unlock(&hdev->cb_list_lock);
+
+ return NULL;
+}
+
+void hci_remove_cb(struct hci_dev *hdev, struct hci_cb_cmd *cmd)
+{
+ BT_DBG("%s remove cmd %p", hdev->name, cmd);
+
+ mutex_lock(&hdev->cb_list_lock);
+ list_del(&cmd->list);
+ mutex_unlock(&hdev->cb_list_lock);
+
+ if (cmd->destructor) {
+ cmd->destructor(hdev, cmd);So what is the purpose of the destructor_cb? A2MP calls hci_cmd_cb and register it, then for some reason A2MP end up calling hci_remove_cb() later, and then cmd->destructor_cb() calls a function that actually belongs to A2MP. What is the advantage here? Or is this meant to be static and only called from hci_cb_clear()?
+ } else {
+ kfree(cmd->opt);
+ kfree(cmd);
+ }
+}
+
+static void hci_cb_clear(struct hci_dev *hdev)
+{
+ struct hci_cb_cmd *cmd, *tmp;
+
+ list_for_each_entry_safe(cmd, tmp, &hdev->cb_list, list)
+ hci_remove_cb(hdev, cmd);
+}
+
+/* Send HCI command with callback */
+int hci_cmd_cb(struct hci_dev *hdev, __u16 opcode, __u32 plen, void *param,
+ void (*cb)(struct hci_dev *hdev, struct hci_cb_cmd *cmd),
+ void *opt,
+ void (*destructor)(struct hci_dev *hdev, struct hci_cb_cmd *cmd),
+ gfp_t flags)
+{
+ int ret;
+
+ if (!cb)
+ return -EINVAL;
+
+ ret = hci_add_cb(hdev, opcode, cb, opt, destructor, flags);Why do you need hci_add_cb()? just put all it code here, it is used only once. Gustavo