Hi Andy,
> Subject: Re: [PATCH v7 0/4] Extend device_get_match_data() to struct
> bus_type
>
> On Fri, Aug 11, 2023 at 01:27:36PM +0000, Biju Das wrote:
> > > On Thu, Aug 10, 2023 at 09:05:10AM +0000, Biju Das wrote:
>
> ...
>
> > > I'm good with this approach, but make sure you checked the whole
> > > kernel source tree for a such.
> >
> > Checking against 16 is too short I guess??
> >
> > drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h has 18 enums.
>
> So, what does prevent us from moving that tables to use pointers?
I think that will lead to ABI breakage(client->name vs id->name)
match = device_get_match_data(&client->dev);
if (match) {
chip_type = (uintptr_t)match;
name = client->name;
} else if (id) {
chip_type = (enum inv_devices)
id->driver_data;
name = id->name;
} else {
return -ENOSYS;
}
>
> > /*device enum */
> > enum inv_devices {
> > INV_MPU6050,
> > INV_MPU6500,
> > INV_MPU6515,
> > INV_MPU6880,
> > INV_MPU6000,
> > INV_MPU9150,
> > INV_MPU9250,
> > INV_MPU9255,
> > INV_ICM20608,
> > INV_ICM20608D,
> > INV_ICM20609,
> > INV_ICM20689,
> > INV_ICM20600,
> > INV_ICM20602,
> > INV_ICM20690,
> > INV_IAM20680,
> > INV_NUM_PARTS
> > };
> >
> > The new helper function
>
> You mean for debugging? We don't need that in production.
That is sample code for iterating through id table to find max enum
and check against ZERO_OR_NULL_PTR
>
> I think what you need is a coccinelle script to find these.
I need to explore using coccinelle script as I have n't tried before.
Cheers,
Biju
On Fri, Aug 11, 2023 at 02:46:10PM +0000, Biju Das wrote:
> > Subject: Re: [PATCH v7 0/4] Extend device_get_match_data() to struct
> > bus_type
> > On Fri, Aug 11, 2023 at 01:27:36PM +0000, Biju Das wrote:
> > > > On Thu, Aug 10, 2023 at 09:05:10AM +0000, Biju Das wrote:
...
> > > > I'm good with this approach, but make sure you checked the whole
> > > > kernel source tree for a such.
> > >
> > > Checking against 16 is too short I guess??
> > >
> > > drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h has 18 enums.
> >
> > So, what does prevent us from moving that tables to use pointers?
>
> I think that will lead to ABI breakage(client->name vs id->name)
>
> match = device_get_match_data(&client->dev);
> if (match) {
> chip_type = (uintptr_t)match;
> name = client->name;
> } else if (id) {
> chip_type = (enum inv_devices)
> id->driver_data;
> name = id->name;
> } else {
> return -ENOSYS;
> }
It's easy to work around (may be better fix can be found, haven't checked, just
what first comes to my mind):
match ...
name = match->name;
/* If enumerated via firmware node, fix the ABI */
if (dev_fwnode())
client->name
> > > /*device enum */
> > > enum inv_devices {
> > > INV_MPU6050,
> > > INV_MPU6500,
> > > INV_MPU6515,
> > > INV_MPU6880,
> > > INV_MPU6000,
> > > INV_MPU9150,
> > > INV_MPU9250,
> > > INV_MPU9255,
> > > INV_ICM20608,
> > > INV_ICM20608D,
> > > INV_ICM20609,
> > > INV_ICM20689,
> > > INV_ICM20600,
> > > INV_ICM20602,
> > > INV_ICM20690,
> > > INV_IAM20680,
> > > INV_NUM_PARTS
> > > };
> > >
> > > The new helper function
> >
> > You mean for debugging? We don't need that in production.
>
> That is sample code for iterating through id table to find max enum
> and check against ZERO_OR_NULL_PTR
Much better with a coccinelle. You will find all or almost all occurrences
without too much effort done.
> > I think what you need is a coccinelle script to find these.
>
> I need to explore using coccinelle script as I have n't tried before.
--
With Best Regards,
Andy Shevchenko
Hi Andy Shevchenko,
Thanks for the feedback.
> Subject: Re: [PATCH v7 0/4] Extend device_get_match_data() to struct
> bus_type
>
> On Fri, Aug 11, 2023 at 02:46:10PM +0000, Biju Das wrote:
> > > Subject: Re: [PATCH v7 0/4] Extend device_get_match_data() to struct
> > > bus_type On Fri, Aug 11, 2023 at 01:27:36PM +0000, Biju Das wrote:
> > > > > On Thu, Aug 10, 2023 at 09:05:10AM +0000, Biju Das wrote:
>
> ...
>
> > > > > I'm good with this approach, but make sure you checked the whole
> > > > > kernel source tree for a such.
> > > >
> > > > Checking against 16 is too short I guess??
> > > >
> > > > drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h has 18 enums.
> > >
> > > So, what does prevent us from moving that tables to use pointers?
> >
> > I think that will lead to ABI breakage(client->name vs id->name)
> >
> > match = device_get_match_data(&client->dev);
> > if (match) {
> > chip_type = (uintptr_t)match;
> > name = client->name;
> > } else if (id) {
> > chip_type = (enum inv_devices)
> > id->driver_data;
> > name = id->name;
> > } else {
> > return -ENOSYS;
> > }
>
>
> It's easy to work around (may be better fix can be found, haven't checked,
> just what first comes to my mind):
>
> match ...
> name = match->name;
The device_get_match_data()API returns matched data, so we cannot use that one here.
Maybe??
/* If enumerated via ID lookup, fix the ABI */
if (!dev_fwnode())
name = id->name;
Cheers,
Biju
>
> /* If enumerated via firmware node, fix the ABI */
> if (dev_fwnode())
> client->name
>
> > > > /*device enum */
> > > > enum inv_devices {
> > > > INV_MPU6050,
> > > > INV_MPU6500,
> > > > INV_MPU6515,
> > > > INV_MPU6880,
> > > > INV_MPU6000,
> > > > INV_MPU9150,
> > > > INV_MPU9250,
> > > > INV_MPU9255,
> > > > INV_ICM20608,
> > > > INV_ICM20608D,
> > > > INV_ICM20609,
> > > > INV_ICM20689,
> > > > INV_ICM20600,
> > > > INV_ICM20602,
> > > > INV_ICM20690,
> > > > INV_IAM20680,
> > > > INV_NUM_PARTS
> > > > };
> > > >
> > > > The new helper function
> > >
> > > You mean for debugging? We don't need that in production.
> >
> > That is sample code for iterating through id table to find max enum
> > and check against ZERO_OR_NULL_PTR
>
> Much better with a coccinelle. You will find all or almost all occurrences
> without too much effort done.
>
> > > I think what you need is a coccinelle script to find these.
> >
> > I need to explore using coccinelle script as I have n't tried before.
>
> --
> With Best Regards,
> Andy Shevchenko
>
On Tue, Aug 15, 2023 at 06:58:41AM +0000, Biju Das wrote: > > Subject: Re: [PATCH v7 0/4] Extend device_get_match_data() to struct > > bus_type > > On Fri, Aug 11, 2023 at 02:46:10PM +0000, Biju Das wrote: ... > > It's easy to work around (may be better fix can be found, haven't checked, > > just what first comes to my mind): > > > > match ... > > name = match->name; > > The device_get_match_data()API returns matched data, so we cannot use that one here. > > Maybe?? > > /* If enumerated via ID lookup, fix the ABI */ > if (!dev_fwnode()) > name = id->name; Yeah, you got the idea. -- With Best Regards, Andy Shevchenko
> Subject: RE: [PATCH v7 0/4] Extend device_get_match_data() to struct
> bus_type
>
>
> Hi Andy Shevchenko,
>
> Thanks for the feedback.
>
> > Subject: Re: [PATCH v7 0/4] Extend device_get_match_data() to struct
> > bus_type
> >
> > On Fri, Aug 11, 2023 at 02:46:10PM +0000, Biju Das wrote:
> > > > Subject: Re: [PATCH v7 0/4] Extend device_get_match_data() to
> > > > struct bus_type On Fri, Aug 11, 2023 at 01:27:36PM +0000, Biju Das
> wrote:
> > > > > > On Thu, Aug 10, 2023 at 09:05:10AM +0000, Biju Das wrote:
> >
> > ...
> >
> > > > > > I'm good with this approach, but make sure you checked the
> > > > > > whole kernel source tree for a such.
> > > > >
> > > > > Checking against 16 is too short I guess??
> > > > >
> > > > > drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h has 18 enums.
> > > >
> > > > So, what does prevent us from moving that tables to use pointers?
> > >
> > > I think that will lead to ABI breakage(client->name vs id->name)
> > >
> > > match = device_get_match_data(&client->dev);
> > > if (match) {
> > > chip_type = (uintptr_t)match;
> > > name = client->name;
> > > } else if (id) {
> > > chip_type = (enum inv_devices)
> > > id->driver_data;
> > > name = id->name;
> > > } else {
> > > return -ENOSYS;
> > > }
> >
> >
> > It's easy to work around (may be better fix can be found, haven't
> > checked, just what first comes to my mind):
> >
> > match ...
> > name = match->name;
>
> The device_get_match_data()API returns matched data, so we cannot use that
> one here.
>
> Maybe??
>
> /* If enumerated via ID lookup, fix the ABI */ if (!dev_fwnode())
> name = id->name;
Looks this will work.
/* If enumerated via firmware node, fix the ABI */
if (dev_fwnode())
name = client->name
else
name = id->name
Cheers,
Biju
Hi Biju,
On Fri, Aug 11, 2023 at 4:46 PM Biju Das <biju.das.jz@bp.renesas.com> wrote:
> > Subject: Re: [PATCH v7 0/4] Extend device_get_match_data() to struct
> > bus_type
> >
> > On Fri, Aug 11, 2023 at 01:27:36PM +0000, Biju Das wrote:
> > > > On Thu, Aug 10, 2023 at 09:05:10AM +0000, Biju Das wrote:
> >
> > ...
> >
> > > > I'm good with this approach, but make sure you checked the whole
> > > > kernel source tree for a such.
> > >
> > > Checking against 16 is too short I guess??
> > >
> > > drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h has 18 enums.
> >
> > So, what does prevent us from moving that tables to use pointers?
>
> I think that will lead to ABI breakage(client->name vs id->name)
>
> match = device_get_match_data(&client->dev);
> if (match) {
> chip_type = (uintptr_t)match;
> name = client->name;
> } else if (id) {
> chip_type = (enum inv_devices)
> id->driver_data;
> name = id->name;
> } else {
> return -ENOSYS;
> }
I don't consider that part of the ABI, as e.g. converting from board files
to DT would change the name.
In addition, using id->name breaks multiple instances of the same device.
I applaud more unification ;-)
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
On Mon, 14 Aug 2023 15:12:24 +0200
Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> Hi Biju,
>
> On Fri, Aug 11, 2023 at 4:46 PM Biju Das <biju.das.jz@bp.renesas.com> wrote:
> > > Subject: Re: [PATCH v7 0/4] Extend device_get_match_data() to struct
> > > bus_type
> > >
> > > On Fri, Aug 11, 2023 at 01:27:36PM +0000, Biju Das wrote:
> > > > > On Thu, Aug 10, 2023 at 09:05:10AM +0000, Biju Das wrote:
> > >
> > > ...
> > >
> > > > > I'm good with this approach, but make sure you checked the whole
> > > > > kernel source tree for a such.
> > > >
> > > > Checking against 16 is too short I guess??
> > > >
> > > > drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h has 18 enums.
> > >
> > > So, what does prevent us from moving that tables to use pointers?
> >
> > I think that will lead to ABI breakage(client->name vs id->name)
> >
> > match = device_get_match_data(&client->dev);
> > if (match) {
> > chip_type = (uintptr_t)match;
> > name = client->name;
> > } else if (id) {
> > chip_type = (enum inv_devices)
> > id->driver_data;
> > name = id->name;
> > } else {
> > return -ENOSYS;
> > }
>
> I don't consider that part of the ABI, as e.g. converting from board files
> to DT would change the name.
> In addition, using id->name breaks multiple instances of the same device.
This has always been a mess as I wasn't paying attention a long time back
and we ended up with some client->name entries being used for iio_dev->name
whereas it should be the part number.
Using id->name is correct choice. This is supposed to be the same for multiple
instances of the same device. There is label and a bunch of other options
for differentiating them including their parent devices.
Problem is that is exported to userspace and often used as part of the
matching when a userspace tool is trying to find the device.
We could 'give it a go' by setting the name in teh switch statement in the core code
and hope no one notices but it's not ideal
https://elixir.bootlin.com/linux/latest/source/drivers/iio/imu/inv_mpu6050/inv_mpu_core.c#L1597
Jonathan
>
> I applaud more unification ;-)
>
> Gr{oetje,eeting}s,
>
> Geert
>
Hi Geert,
Thanks for the feedback.
> Subject: Re: [PATCH v7 0/4] Extend device_get_match_data() to struct
> bus_type
>
> Hi Biju,
>
> On Fri, Aug 11, 2023 at 4:46 PM Biju Das <biju.das.jz@bp.renesas.com>
> wrote:
> > > Subject: Re: [PATCH v7 0/4] Extend device_get_match_data() to struct
> > > bus_type
> > >
> > > On Fri, Aug 11, 2023 at 01:27:36PM +0000, Biju Das wrote:
> > > > > On Thu, Aug 10, 2023 at 09:05:10AM +0000, Biju Das wrote:
> > >
> > > ...
> > >
> > > > > I'm good with this approach, but make sure you checked the whole
> > > > > kernel source tree for a such.
> > > >
> > > > Checking against 16 is too short I guess??
> > > >
> > > > drivers/iio/imu/inv_mpu6050/inv_mpu_iio.h has 18 enums.
> > >
> > > So, what does prevent us from moving that tables to use pointers?
> >
> > I think that will lead to ABI breakage(client->name vs id->name)
> >
> > match = device_get_match_data(&client->dev);
> > if (match) {
> > chip_type = (uintptr_t)match;
> > name = client->name;
> > } else if (id) {
> > chip_type = (enum inv_devices)
> > id->driver_data;
> > name = id->name;
> > } else {
> > return -ENOSYS;
> > }
>
> I don't consider that part of the ABI, as e.g. converting from board files
> to DT would change the name.
> In addition, using id->name breaks multiple instances of the same device.
OK, then according to you this patch is ok [1]?
https://patchwork.kernel.org/project/linux-renesas-soc/patch/20230807172548.258247-2-biju.das.jz@bp.renesas.com/
Cheers,
Biju
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