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 <j...@metanate.com>
---
I saw problems with the -rt patchset on 4.9 and I'm not convinced that
it's Bluetooth at fault for the problem described above, but I think
this is a nice cleanup even if it's not a bug fix.
net/bluetooth/hci_request.c | 30 +++++++-----------------------
1 file changed, 7 insertions(+), 23 deletions(-)
diff --git a/net/bluetooth/hci_request.c b/net/bluetooth/hci_request.c
index 66c0781773df..e44d34734834 100644
--- 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) {
--
2.17.0
