* Gustavo Padovan <padovan@xxxxxxxxxxxxxx> [2011-10-06 22:11:38 -0300]:
> Hi David,
>
> Sorry for the big delay to respond to this.
>
> * David Herrmann <dh.herrmann@xxxxxxxxxxxxxx> [2011-08-26 14:06:02 +0200]:
>
> > Current hidp driver purges the in/out queue on HID shutdown, but does
> > not prevent further I/O. If a driver uses hidp_output_raw_report or
> > hidp_get_raw_report during shutdown, the driver hangs for 5 or 10
> > seconds per call until it gets a timeout.
> > That is, if the output queue of an HID driver has 10 messages pending,
> > it will take 50s until hid_destroy_device() will return. The
> > hidp_session_sem semaphore is held during shutdown so no other HID
> > device may be added/removed during this time.
> >
> > This patch makes hidp_output_raw_report and hidp_get_raw_report fail if
> > session->terminate is true. Also hidp_session will wakeup all current
> > calls to these functions to cancel the current operations.
> >
> > We already purge the current I/O queues on hidp_stop(), so this data loss
> > does not change the behaviour of the HID drivers.
> >
> > Signed-off-by: David Herrmann <dh.herrmann@xxxxxxxxxxxxxx>
> > ---
> > net/bluetooth/hidp/core.c | 40 ++++++++++++++++++++++++++--------------
> > 1 files changed, 26 insertions(+), 14 deletions(-)
> >
> > diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c
> > index 4423e3a..e134528 100644
> > --- a/net/bluetooth/hidp/core.c
> > +++ b/net/bluetooth/hidp/core.c
> > @@ -255,6 +255,9 @@ static int __hidp_send_ctrl_message(struct hidp_session *session,
> >
> > BT_DBG("session %p data %p size %d", session, data, size);
> >
> > + if (atomic_read(&session->terminate))
> > + return -EIO;
> > +
> > skb = alloc_skb(size + 1, GFP_ATOMIC);
> > if (!skb) {
> > BT_ERR("Can't allocate memory for new frame");
> > @@ -320,6 +323,13 @@ static int hidp_send_report(struct hidp_session *session, struct hid_report *rep
> > return hidp_queue_report(session, buf, rsize);
> > }
> >
> > +static void hidp_wakeup_reportq(struct hidp_session *session)
> > +{
> > + clear_bit(HIDP_WAITING_FOR_SEND_ACK, &session->flags);
> > + clear_bit(HIDP_WAITING_FOR_RETURN, &session->flags);
> > + wake_up_interruptible(&session->report_queue);
> > +}
> > +
> > static int hidp_get_raw_report(struct hid_device *hid,
> > unsigned char report_number,
> > unsigned char *data, size_t count,
> > @@ -329,6 +339,7 @@ static int hidp_get_raw_report(struct hid_device *hid,
> > struct sk_buff *skb;
> > size_t len;
> > int numbered_reports = hid->report_enum[report_type].numbered;
> > + int ret;
> >
> > switch (report_type) {
> > case HID_FEATURE_REPORT:
> > @@ -352,8 +363,9 @@ static int hidp_get_raw_report(struct hid_device *hid,
> > session->waiting_report_number = numbered_reports ? report_number : -1;
> > set_bit(HIDP_WAITING_FOR_RETURN, &session->flags);
> > data[0] = report_number;
> > - if (hidp_send_ctrl_message(hid->driver_data, report_type, data, 1))
> > - goto err_eio;
> > + ret = hidp_send_ctrl_message(hid->driver_data, report_type, data, 1);
> > + if (ret)
> > + goto err;
> >
> > /* Wait for the return of the report. The returned report
> > gets put in session->report_return. */
> > @@ -365,11 +377,13 @@ static int hidp_get_raw_report(struct hid_device *hid,
> > 5*HZ);
> > if (res == 0) {
> > /* timeout */
> > - goto err_eio;
> > + ret = -EIO;
> > + goto err;
> > }
> > if (res < 0) {
> > /* signal */
> > - goto err_restartsys;
> > + ret = -ERESTARTSYS;
> > + goto err;
> > }
> > }
> >
> > @@ -390,14 +404,10 @@ static int hidp_get_raw_report(struct hid_device *hid,
> >
> > return len;
> >
> > -err_restartsys:
> > - clear_bit(HIDP_WAITING_FOR_RETURN, &session->flags);
> > - mutex_unlock(&session->report_mutex);
> > - return -ERESTARTSYS;
> > -err_eio:
> > +err:
> > clear_bit(HIDP_WAITING_FOR_RETURN, &session->flags);
> > mutex_unlock(&session->report_mutex);
> > - return -EIO;
> > + return ret;
> > }
> >
> > static int hidp_output_raw_report(struct hid_device *hid, unsigned char *data, size_t count,
> > @@ -422,11 +432,10 @@ static int hidp_output_raw_report(struct hid_device *hid, unsigned char *data, s
> >
> > /* Set up our wait, and send the report request to the device. */
> > set_bit(HIDP_WAITING_FOR_SEND_ACK, &session->flags);
> > - if (hidp_send_ctrl_message(hid->driver_data, report_type,
> > - data, count)) {
> > - ret = -ENOMEM;
> > + ret = hidp_send_ctrl_message(hid->driver_data, report_type, data,
> > + count);
> > + if (ret)
> > goto err;
> > - }
> >
> > /* Wait for the ACK from the device. */
> > while (test_bit(HIDP_WAITING_FOR_SEND_ACK, &session->flags)) {
> > @@ -733,6 +742,9 @@ static int hidp_session(void *arg)
> > remove_wait_queue(sk_sleep(intr_sk), &intr_wait);
> > remove_wait_queue(sk_sleep(ctrl_sk), &ctrl_wait);
> >
> > + atomic_inc(&session->terminate);
>
> At this point seeems that terminate is already > 1.
>
> > + hidp_wakeup_reportq(session);
>
> just inline hidp_wakeup_reportq here, no need to create a function for this.
Nevermind, I fixed it for you. Patch is now applied. Thanks.
Gustavo
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