On Wed, 2013-02-20 at 18:16 +0000, Karl Relton wrote:
> From: Karl Relton <karllinuxtest.relton@xxxxxxxxxxxx>
>
> After linux 3.2 the hid_destroy_device call in hidp_session
> cleaning up invokes a hook to the power_supply code which
> in turn tries to read the battery capacity. This read will
> trigger a call to hidp_get_raw_report which is bound to fail
> because the device is being taken away - so rather than
> wait for the 5 second timeout failure this changes enables
> it to fail straight away.
>
> Signed-off-by: Karl Relton <karllinuxtest.relton@xxxxxxxxxxxx>
> Reviewed-by: David Herrmann <dh.herrmann@xxxxxxxxx>
> ---
> net/bluetooth/hidp/core.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/net/bluetooth/hidp/core.c b/net/bluetooth/hidp/core.c
> index b2bcbe2..4b26ea7 100644
> --- a/net/bluetooth/hidp/core.c
> +++ b/net/bluetooth/hidp/core.c
> @@ -311,6 +311,9 @@ static int hidp_get_raw_report(struct hid_device *hid,
> int numbered_reports = hid->report_enum[report_type].numbered;
> int ret;
>
> + if (atomic_read(&session->terminate))
> + return -EIO;
> +
> switch (report_type) {
Actually I've just realised that hidp_get_raw_report calls
__hidp_send_ctrl_message which already has the session->terminate test,
also returning -EIO on failure. So adding it again here is redundant.
> @@ -722,6 +725,7 @@ static int hidp_session(void *arg)
> set_current_state(TASK_INTERRUPTIBLE);
> }
> set_current_state(TASK_RUNNING);
> + atomic_inc(&session->terminate);
> remove_wait_queue(sk_sleep(intr_sk), &intr_wait);
> remove_wait_queue(sk_sleep(ctrl_sk), &ctrl_wait);
>
So its just this one single line we need - to ensure session->terminate
is non-zero, which will ensure calls to other things (like
hidp_get_raw_report) abort swiftly.
I'll change the patch and send v3 this evening (need to get back to the
day job!).
Karl
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