Bluetooth: use wait_event API instead of open-coding it

I've seen timeout errors from HCI commands where it looks like
schedule_timeout() has returned immediately; additional logging for the
error case gives:

	req_status=1 req_result=0 remaining=10000 jiffies

so the device is still in state HCI_REQ_PEND and the value returned by
schedule_timeout() is the same as the original timeout (HCI_INIT_TIMEOUT
on a system with HZ=1000).

Use wait_event_interruptible_timeout() instead of open-coding similar
behaviour which is subject to the spurious failure described above.

Signed-off-by: John Keeping <john@metanate.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/net/bluetooth/hci_request.c b/net/bluetooth/hci_request.c
index 66c0781..e44d347 100644 (file)
--- a/net/bluetooth/hci_request.c
+++ b/net/bluetooth/hci_request.c
@@ -122,7 +122,6 @@ void hci_req_sync_cancel(struct hci_dev *hdev, int err)
 struct sk_buff *__hci_cmd_sync_ev(struct hci_dev *hdev, u16 opcode, u32 plen,
                                  const void *param, u8 event, u32 timeout)
 {
-       DECLARE_WAITQUEUE(wait, current);
        struct hci_request req;
        struct sk_buff *skb;
        int err = 0;
@@ -135,21 +134,14 @@ struct sk_buff *__hci_cmd_sync_ev(struct hci_dev *hdev, u16 opcode, u32 plen,
 
        hdev->req_status = HCI_REQ_PEND;
 
-       add_wait_queue(&hdev->req_wait_q, &wait);
-       set_current_state(TASK_INTERRUPTIBLE);
-
        err = hci_req_run_skb(&req, hci_req_sync_complete);
-       if (err < 0) {
-               remove_wait_queue(&hdev->req_wait_q, &wait);
-               set_current_state(TASK_RUNNING);
+       if (err < 0)
                return ERR_PTR(err);
-       }
 
-       schedule_timeout(timeout);
+       err = wait_event_interruptible_timeout(hdev->req_wait_q,
+                       hdev->req_status != HCI_REQ_PEND, timeout);
 
-       remove_wait_queue(&hdev->req_wait_q, &wait);
-
-       if (signal_pending(current))
+       if (err == -ERESTARTSYS)
                return ERR_PTR(-EINTR);
 
        switch (hdev->req_status) {
@@ -197,7 +189,6 @@ int __hci_req_sync(struct hci_dev *hdev, int (*func)(struct hci_request *req,
                   unsigned long opt, u32 timeout, u8 *hci_status)
 {
        struct hci_request req;
-       DECLARE_WAITQUEUE(wait, current);
        int err = 0;
 
        BT_DBG("%s start", hdev->name);
@@ -213,16 +204,10 @@ int __hci_req_sync(struct hci_dev *hdev, int (*func)(struct hci_request *req,
                return err;
        }
 
-       add_wait_queue(&hdev->req_wait_q, &wait);
-       set_current_state(TASK_INTERRUPTIBLE);
-
        err = hci_req_run_skb(&req, hci_req_sync_complete);
        if (err < 0) {
                hdev->req_status = 0;
 
-               remove_wait_queue(&hdev->req_wait_q, &wait);
-               set_current_state(TASK_RUNNING);
-
                /* ENODATA means the HCI request command queue is empty.
                 * This can happen when a request with conditionals doesn't
                 * trigger any commands to be sent. This is normal behavior
@@ -240,11 +225,10 @@ int __hci_req_sync(struct hci_dev *hdev, int (*func)(struct hci_request *req,
                return err;
        }
 
-       schedule_timeout(timeout);
-
-       remove_wait_queue(&hdev->req_wait_q, &wait);
+       err = wait_event_interruptible_timeout(hdev->req_wait_q,
+                       hdev->req_status != HCI_REQ_PEND, timeout);
 
-       if (signal_pending(current))
+       if (err == -ERESTARTSYS)
                return -EINTR;
 
        switch (hdev->req_status) {