2022-01-13 09:01:49

by Archie Pusaka

[permalink] [raw]
Subject: [Bluez PATCH] device: Fix device can't be scanned for 5 mins after reboot

From: Archie Pusaka <[email protected]>

After the patches which limit the attempts of doing remote name
resolving, there's an issue which prevents BlueZ to RNR new devices
for 5 minutes after reboot. It's caused by failed_time is init to 0,
and is then treated as the timestamp when the device failed RNR.
However, actually there is no failure yet.

This CL fixes it by always allowing RNR when failed_time = 0.

Reviewed-by: Shuo-Peng Liao <[email protected]>
---

src/device.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/device.c b/src/device.c
index f2447c478e..16b1ed5bd3 100644
--- a/src/device.c
+++ b/src/device.c
@@ -4487,10 +4487,15 @@ bool device_is_name_resolve_allowed(struct btd_device *device)

clock_gettime(CLOCK_MONOTONIC, &now);

- /* If now < failed_time, it means the clock has somehow turned back,
- * possibly because of system restart. Allow name request in this case.
+ /* Allow name request for any of these cases:
+ * (1) failed_time is empty (0). Meaning no prior failure.
+ * (2) now < failed_time. Meaning the clock has somehow turned back,
+ * possibly because of system restart. Allow just to be safe.
+ * (3) now >= failed_time + name_request_retry_delay. Meaning the
+ * period of not sending name request is over.
*/
- return now.tv_sec < device->name_resolve_failed_time ||
+ return device->name_resolve_failed_time == 0 ||
+ now.tv_sec < device->name_resolve_failed_time ||
now.tv_sec >= device->name_resolve_failed_time +
btd_opts.name_request_retry_delay;
}
--
2.34.1.575.g55b058a8bb-goog


2022-01-13 09:11:43

by Marcel Holtmann

[permalink] [raw]
Subject: Re: [Bluez PATCH] device: Fix device can't be scanned for 5 mins after reboot

Hi Archie,

> After the patches which limit the attempts of doing remote name
> resolving, there's an issue which prevents BlueZ to RNR new devices
> for 5 minutes after reboot. It's caused by failed_time is init to 0,
> and is then treated as the timestamp when the device failed RNR.
> However, actually there is no failure yet.
>
> This CL fixes it by always allowing RNR when failed_time = 0.
>
> Reviewed-by: Shuo-Peng Liao <[email protected]>
> ---
>
> src/device.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/src/device.c b/src/device.c
> index f2447c478e..16b1ed5bd3 100644
> --- a/src/device.c
> +++ b/src/device.c
> @@ -4487,10 +4487,15 @@ bool device_is_name_resolve_allowed(struct btd_device *device)
>
> clock_gettime(CLOCK_MONOTONIC, &now);
>
> - /* If now < failed_time, it means the clock has somehow turned back,
> - * possibly because of system restart. Allow name request in this case.
> + /* Allow name request for any of these cases:
> + * (1) failed_time is empty (0). Meaning no prior failure.
> + * (2) now < failed_time. Meaning the clock has somehow turned back,
> + * possibly because of system restart. Allow just to be safe.
> + * (3) now >= failed_time + name_request_retry_delay. Meaning the
> + * period of not sending name request is over.
> */
> - return now.tv_sec < device->name_resolve_failed_time ||
> + return device->name_resolve_failed_time == 0 ||
> + now.tv_sec < device->name_resolve_failed_time ||
> now.tv_sec >= device->name_resolve_failed_time +
> btd_opts.name_request_retry_delay;
> }

I have the feeling this becomes complex and hard to follow. I appreciate the comment above, but just for thoughts, would it be better to do something like this:

/* failed_time is empty (0). Meaning no prior failure. */
if (device->name_..failed_time == 0)
return true;

..

return false;

Regards

Marcel

2022-01-13 09:16:50

by bluez.test.bot

[permalink] [raw]
Subject: RE: [Bluez] device: Fix device can't be scanned for 5 mins after reboot

This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=605086

---Test result---

Test Summary:
CheckPatch PASS 1.37 seconds
GitLint PASS 1.00 seconds
Prep - Setup ELL PASS 42.67 seconds
Build - Prep PASS 0.67 seconds
Build - Configure PASS 8.57 seconds
Build - Make PASS 1416.24 seconds
Make Check PASS 12.01 seconds
Make Check w/Valgrind PASS 446.97 seconds
Make Distcheck PASS 219.77 seconds
Build w/ext ELL - Configure PASS 8.66 seconds
Build w/ext ELL - Make PASS 1400.11 seconds
Incremental Build with patchesPASS 0.00 seconds



---
Regards,
Linux Bluetooth

2022-01-13 11:59:16

by Archie Pusaka

[permalink] [raw]
Subject: Re: [Bluez PATCH] device: Fix device can't be scanned for 5 mins after reboot

Hi Marcel,

On Thu, 13 Jan 2022 at 15:05, Marcel Holtmann <[email protected]> wrote:
>
> Hi Archie,
>
> > After the patches which limit the attempts of doing remote name
> > resolving, there's an issue which prevents BlueZ to RNR new devices
> > for 5 minutes after reboot. It's caused by failed_time is init to 0,
> > and is then treated as the timestamp when the device failed RNR.
> > However, actually there is no failure yet.
> >
> > This CL fixes it by always allowing RNR when failed_time = 0.
> >
> > Reviewed-by: Shuo-Peng Liao <[email protected]>
> > ---
> >
> > src/device.c | 11 ++++++++---
> > 1 file changed, 8 insertions(+), 3 deletions(-)
> >
> > diff --git a/src/device.c b/src/device.c
> > index f2447c478e..16b1ed5bd3 100644
> > --- a/src/device.c
> > +++ b/src/device.c
> > @@ -4487,10 +4487,15 @@ bool device_is_name_resolve_allowed(struct btd_device *device)
> >
> > clock_gettime(CLOCK_MONOTONIC, &now);
> >
> > - /* If now < failed_time, it means the clock has somehow turned back,
> > - * possibly because of system restart. Allow name request in this case.
> > + /* Allow name request for any of these cases:
> > + * (1) failed_time is empty (0). Meaning no prior failure.
> > + * (2) now < failed_time. Meaning the clock has somehow turned back,
> > + * possibly because of system restart. Allow just to be safe.
> > + * (3) now >= failed_time + name_request_retry_delay. Meaning the
> > + * period of not sending name request is over.
> > */
> > - return now.tv_sec < device->name_resolve_failed_time ||
> > + return device->name_resolve_failed_time == 0 ||
> > + now.tv_sec < device->name_resolve_failed_time ||
> > now.tv_sec >= device->name_resolve_failed_time +
> > btd_opts.name_request_retry_delay;
> > }
>
> I have the feeling this becomes complex and hard to follow. I appreciate the comment above, but just for thoughts, would it be better to do something like this:
>
> /* failed_time is empty (0). Meaning no prior failure. */
> if (device->name_..failed_time == 0)
> return true;
>
> ..
>
> return false;
>

I actually prefer your suggestion, this makes the code much easier to read.
However it's not a very common pattern I observe so I went with the
previous approach.

I have sent a v2 to separate the big if, please take a look.

Thanks,
Archie

> Regards
>
> Marcel
>