* Re: [PATCH] [v2] platform/surface: aggregator: avoid clang -Wconstant-conversion warning
2021-05-14 20:04 [PATCH] [v2] platform/surface: aggregator: avoid clang -Wconstant-conversion warning Arnd Bergmann
@ 2021-05-14 21:22 ` Nathan Chancellor
2021-05-17 8:31 ` David Laight
2021-05-14 21:56 ` Maximilian Luz
2021-05-19 13:12 ` Hans de Goede
2 siblings, 1 reply; 6+ messages in thread
From: Nathan Chancellor @ 2021-05-14 21:22 UTC (permalink / raw)
To: Arnd Bergmann, Maximilian Luz, Hans de Goede
Cc: Arnd Bergmann, platform-driver-x86, Nick Desaulniers,
linux-kernel, clang-built-linux
On 5/14/2021 1:04 PM, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> Clang complains about the assignment of SSAM_ANY_IID to
> ssam_device_uid->instance:
>
> drivers/platform/surface/surface_aggregator_registry.c:478:25: error: implicit conversion from 'int' to '__u8' (aka 'unsigned char') changes value from 65535 to 255 [-Werror,-Wconstant-conversion]
> { SSAM_VDEV(HUB, 0x02, SSAM_ANY_IID, 0x00) },
> ~ ^~~~~~~~~~~~
> include/linux/surface_aggregator/device.h:71:23: note: expanded from macro 'SSAM_ANY_IID'
> #define SSAM_ANY_IID 0xffff
> ^~~~~~
> include/linux/surface_aggregator/device.h:126:63: note: expanded from macro 'SSAM_VDEV'
> SSAM_DEVICE(SSAM_DOMAIN_VIRTUAL, SSAM_VIRTUAL_TC_##cat, tid, iid, fun)
> ^~~
> include/linux/surface_aggregator/device.h:102:41: note: expanded from macro 'SSAM_DEVICE'
> .instance = ((iid) != SSAM_ANY_IID) ? (iid) : 0, \
> ^~~
>
> The assignment doesn't actually happen, but clang checks the type limits
> before checking whether this assignment is reached. Replace the ?:
> operator with a __builtin_choose_expr() invocation that avoids the
> warning for the untaken part.
>
> Fixes: eb0e90a82098 ("platform/surface: aggregator: Add dedicated bus and device type")
> Cc: platform-driver-x86@vger.kernel.org
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
> ---
> v2: use __builtin_choose_expr() instead of a cast to shut up the warning
> ---
> include/linux/surface_aggregator/device.h | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/surface_aggregator/device.h b/include/linux/surface_aggregator/device.h
> index 4441ad667c3f..6ff9c58b3e17 100644
> --- a/include/linux/surface_aggregator/device.h
> +++ b/include/linux/surface_aggregator/device.h
> @@ -98,9 +98,9 @@ struct ssam_device_uid {
> | (((fun) != SSAM_ANY_FUN) ? SSAM_MATCH_FUNCTION : 0), \
> .domain = d, \
> .category = cat, \
> - .target = ((tid) != SSAM_ANY_TID) ? (tid) : 0, \
> - .instance = ((iid) != SSAM_ANY_IID) ? (iid) : 0, \
> - .function = ((fun) != SSAM_ANY_FUN) ? (fun) : 0 \
> + .target = __builtin_choose_expr((tid) != SSAM_ANY_TID, (tid), 0), \
> + .instance = __builtin_choose_expr((iid) != SSAM_ANY_IID, (iid), 0), \
> + .function = __builtin_choose_expr((fun) != SSAM_ANY_FUN, (fun), 0)
>
> /**
> * SSAM_VDEV() - Initialize a &struct ssam_device_id as virtual device with
>
^ permalink raw reply [flat|nested] 6+ messages in thread* RE: [PATCH] [v2] platform/surface: aggregator: avoid clang -Wconstant-conversion warning
2021-05-14 21:22 ` Nathan Chancellor
@ 2021-05-17 8:31 ` David Laight
2021-05-17 12:40 ` Maximilian Luz
0 siblings, 1 reply; 6+ messages in thread
From: David Laight @ 2021-05-17 8:31 UTC (permalink / raw)
To: 'Nathan Chancellor',
Arnd Bergmann, Maximilian Luz, Hans de Goede
Cc: Arnd Bergmann, platform-driver-x86, Nick Desaulniers,
linux-kernel, clang-built-linux
From: Nathan Chancellor
> Sent: 14 May 2021 22:23
> >
> > Clang complains about the assignment of SSAM_ANY_IID to
> > ssam_device_uid->instance:
Has this been raised with clang?
...
> > - .target = ((tid) != SSAM_ANY_TID) ? (tid) : 0, \
> > - .instance = ((iid) != SSAM_ANY_IID) ? (iid) : 0, \
> > - .function = ((fun) != SSAM_ANY_FUN) ? (fun) : 0 \
> > + .target = __builtin_choose_expr((tid) != SSAM_ANY_TID, (tid), 0), \
> > + .instance = __builtin_choose_expr((iid) != SSAM_ANY_IID, (iid), 0), \
> > + .function = __builtin_choose_expr((fun) != SSAM_ANY_FUN, (fun), 0)
A simpler alternative:
= fun * (fun != SSAM_ANY_FUN)
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] [v2] platform/surface: aggregator: avoid clang -Wconstant-conversion warning
2021-05-17 8:31 ` David Laight
@ 2021-05-17 12:40 ` Maximilian Luz
0 siblings, 0 replies; 6+ messages in thread
From: Maximilian Luz @ 2021-05-17 12:40 UTC (permalink / raw)
To: David Laight, 'Nathan Chancellor', Arnd Bergmann, Hans de Goede
Cc: Arnd Bergmann, platform-driver-x86, Nick Desaulniers,
linux-kernel, clang-built-linux
On 5/17/21 10:31 AM, David Laight wrote:
> From: Nathan Chancellor
>> Sent: 14 May 2021 22:23
>>>
>>> Clang complains about the assignment of SSAM_ANY_IID to
>>> ssam_device_uid->instance:
>
> Has this been raised with clang?
I believe so, see this earlier report:
https://lore.kernel.org/linux-mm/20210311185154.6uysryumfho73zlb@archlinux-ax161/
Regards,
Max
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] [v2] platform/surface: aggregator: avoid clang -Wconstant-conversion warning
2021-05-14 20:04 [PATCH] [v2] platform/surface: aggregator: avoid clang -Wconstant-conversion warning Arnd Bergmann
2021-05-14 21:22 ` Nathan Chancellor
@ 2021-05-14 21:56 ` Maximilian Luz
2021-05-19 13:12 ` Hans de Goede
2 siblings, 0 replies; 6+ messages in thread
From: Maximilian Luz @ 2021-05-14 21:56 UTC (permalink / raw)
To: Arnd Bergmann, Hans de Goede
Cc: Arnd Bergmann, platform-driver-x86, Nathan Chancellor,
Nick Desaulniers, linux-kernel, clang-built-linux
On 14/05/2021 22:04, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> Clang complains about the assignment of SSAM_ANY_IID to
> ssam_device_uid->instance:
>
> drivers/platform/surface/surface_aggregator_registry.c:478:25: error: implicit conversion from 'int' to '__u8' (aka 'unsigned char') changes value from 65535 to 255 [-Werror,-Wconstant-conversion]
> { SSAM_VDEV(HUB, 0x02, SSAM_ANY_IID, 0x00) },
> ~ ^~~~~~~~~~~~
> include/linux/surface_aggregator/device.h:71:23: note: expanded from macro 'SSAM_ANY_IID'
> #define SSAM_ANY_IID 0xffff
> ^~~~~~
> include/linux/surface_aggregator/device.h:126:63: note: expanded from macro 'SSAM_VDEV'
> SSAM_DEVICE(SSAM_DOMAIN_VIRTUAL, SSAM_VIRTUAL_TC_##cat, tid, iid, fun)
> ^~~
> include/linux/surface_aggregator/device.h:102:41: note: expanded from macro 'SSAM_DEVICE'
> .instance = ((iid) != SSAM_ANY_IID) ? (iid) : 0, \
> ^~~
>
> The assignment doesn't actually happen, but clang checks the type limits
> before checking whether this assignment is reached. Replace the ?:
> operator with a __builtin_choose_expr() invocation that avoids the
> warning for the untaken part.
>
> Fixes: eb0e90a82098 ("platform/surface: aggregator: Add dedicated bus and device type")
> Cc: platform-driver-x86@vger.kernel.org
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Thanks! This looks good to me.
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com>
> ---
> v2: use __builtin_choose_expr() instead of a cast to shut up the warning
> ---
> include/linux/surface_aggregator/device.h | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/surface_aggregator/device.h b/include/linux/surface_aggregator/device.h
> index 4441ad667c3f..6ff9c58b3e17 100644
> --- a/include/linux/surface_aggregator/device.h
> +++ b/include/linux/surface_aggregator/device.h
> @@ -98,9 +98,9 @@ struct ssam_device_uid {
> | (((fun) != SSAM_ANY_FUN) ? SSAM_MATCH_FUNCTION : 0), \
> .domain = d, \
> .category = cat, \
> - .target = ((tid) != SSAM_ANY_TID) ? (tid) : 0, \
> - .instance = ((iid) != SSAM_ANY_IID) ? (iid) : 0, \
> - .function = ((fun) != SSAM_ANY_FUN) ? (fun) : 0 \
> + .target = __builtin_choose_expr((tid) != SSAM_ANY_TID, (tid), 0), \
> + .instance = __builtin_choose_expr((iid) != SSAM_ANY_IID, (iid), 0), \
> + .function = __builtin_choose_expr((fun) != SSAM_ANY_FUN, (fun), 0)
>
> /**
> * SSAM_VDEV() - Initialize a &struct ssam_device_id as virtual device with
>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] [v2] platform/surface: aggregator: avoid clang -Wconstant-conversion warning
2021-05-14 20:04 [PATCH] [v2] platform/surface: aggregator: avoid clang -Wconstant-conversion warning Arnd Bergmann
2021-05-14 21:22 ` Nathan Chancellor
2021-05-14 21:56 ` Maximilian Luz
@ 2021-05-19 13:12 ` Hans de Goede
2 siblings, 0 replies; 6+ messages in thread
From: Hans de Goede @ 2021-05-19 13:12 UTC (permalink / raw)
To: Arnd Bergmann, Maximilian Luz
Cc: Arnd Bergmann, platform-driver-x86, Nathan Chancellor,
Nick Desaulniers, linux-kernel, clang-built-linux
Hi,
On 5/14/21 10:04 PM, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> Clang complains about the assignment of SSAM_ANY_IID to
> ssam_device_uid->instance:
>
> drivers/platform/surface/surface_aggregator_registry.c:478:25: error: implicit conversion from 'int' to '__u8' (aka 'unsigned char') changes value from 65535 to 255 [-Werror,-Wconstant-conversion]
> { SSAM_VDEV(HUB, 0x02, SSAM_ANY_IID, 0x00) },
> ~ ^~~~~~~~~~~~
> include/linux/surface_aggregator/device.h:71:23: note: expanded from macro 'SSAM_ANY_IID'
> #define SSAM_ANY_IID 0xffff
> ^~~~~~
> include/linux/surface_aggregator/device.h:126:63: note: expanded from macro 'SSAM_VDEV'
> SSAM_DEVICE(SSAM_DOMAIN_VIRTUAL, SSAM_VIRTUAL_TC_##cat, tid, iid, fun)
> ^~~
> include/linux/surface_aggregator/device.h:102:41: note: expanded from macro 'SSAM_DEVICE'
> .instance = ((iid) != SSAM_ANY_IID) ? (iid) : 0, \
> ^~~
>
> The assignment doesn't actually happen, but clang checks the type limits
> before checking whether this assignment is reached. Replace the ?:
> operator with a __builtin_choose_expr() invocation that avoids the
> warning for the untaken part.
>
> Fixes: eb0e90a82098 ("platform/surface: aggregator: Add dedicated bus and device type")
> Cc: platform-driver-x86@vger.kernel.org
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Thank you for your patch, I've applied this patch to my review-hans
branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans
I will also include this in the next pdx86-fixes pull-req for 5.13.
Note it will show up in my review-hans branch once I've pushed my
local branch there, which might take a while.
Once I've run some tests on this branch the patches there will be
added to the platform-drivers-x86/for-next branch and eventually
will be included in the pdx86 pull-request to Linus for the next
merge-window.
Regards,
Hans
> ---
> v2: use __builtin_choose_expr() instead of a cast to shut up the warning
> ---
> include/linux/surface_aggregator/device.h | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/surface_aggregator/device.h b/include/linux/surface_aggregator/device.h
> index 4441ad667c3f..6ff9c58b3e17 100644
> --- a/include/linux/surface_aggregator/device.h
> +++ b/include/linux/surface_aggregator/device.h
> @@ -98,9 +98,9 @@ struct ssam_device_uid {
> | (((fun) != SSAM_ANY_FUN) ? SSAM_MATCH_FUNCTION : 0), \
> .domain = d, \
> .category = cat, \
> - .target = ((tid) != SSAM_ANY_TID) ? (tid) : 0, \
> - .instance = ((iid) != SSAM_ANY_IID) ? (iid) : 0, \
> - .function = ((fun) != SSAM_ANY_FUN) ? (fun) : 0 \
> + .target = __builtin_choose_expr((tid) != SSAM_ANY_TID, (tid), 0), \
> + .instance = __builtin_choose_expr((iid) != SSAM_ANY_IID, (iid), 0), \
> + .function = __builtin_choose_expr((fun) != SSAM_ANY_FUN, (fun), 0)
>
> /**
> * SSAM_VDEV() - Initialize a &struct ssam_device_id as virtual device with
>
^ permalink raw reply [flat|nested] 6+ messages in thread