* Re: [PATCH] Staging: nvec: Change container_of macro to an inline function.
2023-03-18 17:05 [PATCH] Staging: nvec: Change container_of macro to an inline function Sumitra Sharma
@ 2023-03-18 17:14 ` Julia Lawall
2023-03-18 17:55 ` Sumitra Sharma
2023-03-18 18:55 ` kernel test robot
2023-03-18 20:48 ` kernel test robot
2 siblings, 1 reply; 6+ messages in thread
From: Julia Lawall @ 2023-03-18 17:14 UTC (permalink / raw)
To: Sumitra Sharma
Cc: Marc Dietrich, Greg Kroah-Hartman, ac100, linux-tegra,
linux-staging, linux-kernel, outreachy
On Sat, 18 Mar 2023, Sumitra Sharma wrote:
> The macro has the drawback that one cannot determine
> what type it applies to by looking at the definition.
> Hence this macro definition is not type-safe.
>
> The inline function gives the same benefits as the
> macro and only accepts the specific type of arguments.
> Use static because the definition only requires it to be
> visible in the current file.
Sumitra,
The subject line and log message could be a little less generic. For the
subject line, one has the impression that you are changing the definition
of container_of itself.
The log message is also a bit wordy. Something like the following would
be more concise and still present the issue:
Convert to_nvec_led from a macro to an inline function, to make the
relevant types apparent in the definition and to benefit from the type
checking performed by the compiler at call sites.
julia
>
> Signed-off-by: Sumitra Sharma <sumitraartsy@gmail.com>
> ---
> drivers/staging/nvec/nvec_paz00.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/nvec/nvec_paz00.c b/drivers/staging/nvec/nvec_paz00.c
> index 8b4da95081c8..9573ba762cdd 100644
> --- a/drivers/staging/nvec/nvec_paz00.c
> +++ b/drivers/staging/nvec/nvec_paz00.c
> @@ -14,8 +14,10 @@
> #include <linux/platform_device.h>
> #include "nvec.h"
>
> -#define to_nvec_led(led_cdev) \
> - container_of(led_cdev, struct nvec_led, cdev)
> +static inline struct nvec_led *to_nvec_led(struct led_classdev *led_cdev)
> +{
> + return container_of(led_cdev, struct nvec_led, cdev);
> +}
>
> #define NVEC_LED_REQ {'\x0d', '\x10', '\x45', '\x10', '\x00'}
>
> --
> 2.25.1
>
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] Staging: nvec: Change container_of macro to an inline function.
2023-03-18 17:14 ` Julia Lawall
@ 2023-03-18 17:55 ` Sumitra Sharma
2023-03-20 21:10 ` Ira Weiny
0 siblings, 1 reply; 6+ messages in thread
From: Sumitra Sharma @ 2023-03-18 17:55 UTC (permalink / raw)
To: Julia Lawall
Cc: Marc Dietrich, Greg Kroah-Hartman, ac100, linux-tegra,
linux-staging, linux-kernel, outreachy
On Sat, Mar 18, 2023 at 06:14:50PM +0100, Julia Lawall wrote:
>
>
> On Sat, 18 Mar 2023, Sumitra Sharma wrote:
>
> > The macro has the drawback that one cannot determine
> > what type it applies to by looking at the definition.
> > Hence this macro definition is not type-safe.
> >
> > The inline function gives the same benefits as the
> > macro and only accepts the specific type of arguments.
> > Use static because the definition only requires it to be
> > visible in the current file.
>
> Sumitra,
>
> The subject line and log message could be a little less generic. For the
> subject line, one has the impression that you are changing the definition
> of container_of itself.
>
> The log message is also a bit wordy. Something like the following would
> be more concise and still present the issue:
>
Okay. I will focus more on writing better patch subject and description.
Thanks.
Regards,
Sumitra
> Convert to_nvec_led from a macro to an inline function, to make the
> relevant types apparent in the definition and to benefit from the type
> checking performed by the compiler at call sites.
>
> julia
>
>
> >
> > Signed-off-by: Sumitra Sharma <sumitraartsy@gmail.com>
> > ---
> > drivers/staging/nvec/nvec_paz00.c | 6 ++++--
> > 1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/staging/nvec/nvec_paz00.c b/drivers/staging/nvec/nvec_paz00.c
> > index 8b4da95081c8..9573ba762cdd 100644
> > --- a/drivers/staging/nvec/nvec_paz00.c
> > +++ b/drivers/staging/nvec/nvec_paz00.c
> > @@ -14,8 +14,10 @@
> > #include <linux/platform_device.h>
> > #include "nvec.h"
> >
> > -#define to_nvec_led(led_cdev) \
> > - container_of(led_cdev, struct nvec_led, cdev)
> > +static inline struct nvec_led *to_nvec_led(struct led_classdev *led_cdev)
> > +{
> > + return container_of(led_cdev, struct nvec_led, cdev);
> > +}
> >
> > #define NVEC_LED_REQ {'\x0d', '\x10', '\x45', '\x10', '\x00'}
> >
> > --
> > 2.25.1
> >
> >
> >
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] Staging: nvec: Change container_of macro to an inline function.
2023-03-18 17:55 ` Sumitra Sharma
@ 2023-03-20 21:10 ` Ira Weiny
0 siblings, 0 replies; 6+ messages in thread
From: Ira Weiny @ 2023-03-20 21:10 UTC (permalink / raw)
To: Sumitra Sharma, Julia Lawall
Cc: Marc Dietrich, Greg Kroah-Hartman, ac100, linux-tegra,
linux-staging, linux-kernel, outreachy
Sumitra Sharma wrote:
> On Sat, Mar 18, 2023 at 06:14:50PM +0100, Julia Lawall wrote:
> >
> >
> > On Sat, 18 Mar 2023, Sumitra Sharma wrote:
> >
> > > The macro has the drawback that one cannot determine
> > > what type it applies to by looking at the definition.
> > > Hence this macro definition is not type-safe.
> > >
> > > The inline function gives the same benefits as the
> > > macro and only accepts the specific type of arguments.
> > > Use static because the definition only requires it to be
> > > visible in the current file.
> >
> > Sumitra,
> >
> > The subject line and log message could be a little less generic. For the
> > subject line, one has the impression that you are changing the definition
> > of container_of itself.
> >
> > The log message is also a bit wordy. Something like the following would
> > be more concise and still present the issue:
> >
>
> Okay. I will focus more on writing better patch subject and description.
Sumitra,
I can't tell for sure via email if you are getting discouraged. But if you are
don't feel bad. Writing good commit messages is hard.
That said, I see a couple of build errors from 0day on this patch. Do use the
tools to correct things like that before submitting.
Ira
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] Staging: nvec: Change container_of macro to an inline function.
2023-03-18 17:05 [PATCH] Staging: nvec: Change container_of macro to an inline function Sumitra Sharma
2023-03-18 17:14 ` Julia Lawall
@ 2023-03-18 18:55 ` kernel test robot
2023-03-18 20:48 ` kernel test robot
2 siblings, 0 replies; 6+ messages in thread
From: kernel test robot @ 2023-03-18 18:55 UTC (permalink / raw)
To: Sumitra Sharma, Marc Dietrich, Greg Kroah-Hartman, ac100,
linux-tegra, linux-staging, linux-kernel, outreachy
Cc: llvm, oe-kbuild-all
Hi Sumitra,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on staging/staging-testing]
url: https://github.com/intel-lab-lkp/linux/commits/Sumitra-Sharma/Staging-nvec-Change-container_of-macro-to-an-inline-function/20230319-010628
patch link: https://lore.kernel.org/r/20230318170514.GA49181%40sumitra.com
patch subject: [PATCH] Staging: nvec: Change container_of macro to an inline function.
config: arm64-randconfig-r014-20230319 (https://download.01.org/0day-ci/archive/20230319/202303190233.v2KJFmIG-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project 67409911353323ca5edf2049ef0df54132fa1ca7)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install arm64 cross compiling tool for clang build
# apt-get install binutils-aarch64-linux-gnu
# https://github.com/intel-lab-lkp/linux/commit/e58807d27f0ba705144bce72751f5cb0a75b9682
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Sumitra-Sharma/Staging-nvec-Change-container_of-macro-to-an-inline-function/20230319-010628
git checkout e58807d27f0ba705144bce72751f5cb0a75b9682
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm64 olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm64 SHELL=/bin/bash drivers/staging/nvec/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202303190233.v2KJFmIG-lkp@intel.com/
All errors (new ones prefixed by >>):
>> drivers/staging/nvec/nvec_paz00.c:19:9: error: incomplete definition of type 'struct nvec_led'
return container_of(led_cdev, struct nvec_led, cdev);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/container_of.h:20:47: note: expanded from macro 'container_of'
static_assert(__same_type(*(ptr), ((type *)0)->member) || \
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~
include/linux/compiler_types.h:338:74: note: expanded from macro '__same_type'
#define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
^
include/linux/build_bug.h:77:50: note: expanded from macro 'static_assert'
#define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr)
~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:78:56: note: expanded from macro '__static_assert'
#define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
^~~~
drivers/staging/nvec/nvec_paz00.c:17:22: note: forward declaration of 'struct nvec_led'
static inline struct nvec_led *to_nvec_led(struct led_classdev *led_cdev)
^
>> drivers/staging/nvec/nvec_paz00.c:19:9: error: offsetof of incomplete type 'struct nvec_led'
return container_of(led_cdev, struct nvec_led, cdev);
^ ~~~~~~
include/linux/container_of.h:23:21: note: expanded from macro 'container_of'
((type *)(__mptr - offsetof(type, member))); })
^ ~~~~
include/linux/stddef.h:16:32: note: expanded from macro 'offsetof'
#define offsetof(TYPE, MEMBER) __builtin_offsetof(TYPE, MEMBER)
^ ~~~~
drivers/staging/nvec/nvec_paz00.c:17:22: note: forward declaration of 'struct nvec_led'
static inline struct nvec_led *to_nvec_led(struct led_classdev *led_cdev)
^
>> drivers/staging/nvec/nvec_paz00.c:19:9: error: returning 'void' from a function with incompatible result type 'struct nvec_led *'
return container_of(led_cdev, struct nvec_led, cdev);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/container_of.h:18:41: note: expanded from macro 'container_of'
#define container_of(ptr, type, member) ({ \
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3 errors generated.
vim +19 drivers/staging/nvec/nvec_paz00.c
16
17 static inline struct nvec_led *to_nvec_led(struct led_classdev *led_cdev)
18 {
> 19 return container_of(led_cdev, struct nvec_led, cdev);
20 }
21
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] Staging: nvec: Change container_of macro to an inline function.
2023-03-18 17:05 [PATCH] Staging: nvec: Change container_of macro to an inline function Sumitra Sharma
2023-03-18 17:14 ` Julia Lawall
2023-03-18 18:55 ` kernel test robot
@ 2023-03-18 20:48 ` kernel test robot
2 siblings, 0 replies; 6+ messages in thread
From: kernel test robot @ 2023-03-18 20:48 UTC (permalink / raw)
To: Sumitra Sharma, Marc Dietrich, Greg Kroah-Hartman, ac100,
linux-tegra, linux-staging, linux-kernel, outreachy
Cc: oe-kbuild-all
Hi Sumitra,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on staging/staging-testing]
url: https://github.com/intel-lab-lkp/linux/commits/Sumitra-Sharma/Staging-nvec-Change-container_of-macro-to-an-inline-function/20230319-010628
patch link: https://lore.kernel.org/r/20230318170514.GA49181%40sumitra.com
patch subject: [PATCH] Staging: nvec: Change container_of macro to an inline function.
config: arm-allyesconfig (https://download.01.org/0day-ci/archive/20230319/202303190432.kRoDGmiE-lkp@intel.com/config)
compiler: arm-linux-gnueabi-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/e58807d27f0ba705144bce72751f5cb0a75b9682
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Sumitra-Sharma/Staging-nvec-Change-container_of-macro-to-an-inline-function/20230319-010628
git checkout e58807d27f0ba705144bce72751f5cb0a75b9682
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=arm olddefconfig
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash drivers/staging/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202303190432.kRoDGmiE-lkp@intel.com/
All errors (new ones prefixed by >>):
In file included from include/linux/container_of.h:5,
from include/linux/list.h:5,
from include/linux/module.h:12,
from drivers/staging/nvec/nvec_paz00.c:10:
drivers/staging/nvec/nvec_paz00.c: In function 'to_nvec_led':
>> include/linux/container_of.h:20:54: error: invalid use of undefined type 'struct nvec_led'
20 | static_assert(__same_type(*(ptr), ((type *)0)->member) || \
| ^~
include/linux/build_bug.h:78:56: note: in definition of macro '__static_assert'
78 | #define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
| ^~~~
include/linux/container_of.h:20:9: note: in expansion of macro 'static_assert'
20 | static_assert(__same_type(*(ptr), ((type *)0)->member) || \
| ^~~~~~~~~~~~~
include/linux/container_of.h:20:23: note: in expansion of macro '__same_type'
20 | static_assert(__same_type(*(ptr), ((type *)0)->member) || \
| ^~~~~~~~~~~
drivers/staging/nvec/nvec_paz00.c:19:16: note: in expansion of macro 'container_of'
19 | return container_of(led_cdev, struct nvec_led, cdev);
| ^~~~~~~~~~~~
include/linux/compiler_types.h:338:27: error: expression in static assertion is not an integer
338 | #define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/build_bug.h:78:56: note: in definition of macro '__static_assert'
78 | #define __static_assert(expr, msg, ...) _Static_assert(expr, msg)
| ^~~~
include/linux/container_of.h:20:9: note: in expansion of macro 'static_assert'
20 | static_assert(__same_type(*(ptr), ((type *)0)->member) || \
| ^~~~~~~~~~~~~
include/linux/container_of.h:20:23: note: in expansion of macro '__same_type'
20 | static_assert(__same_type(*(ptr), ((type *)0)->member) || \
| ^~~~~~~~~~~
drivers/staging/nvec/nvec_paz00.c:19:16: note: in expansion of macro 'container_of'
19 | return container_of(led_cdev, struct nvec_led, cdev);
| ^~~~~~~~~~~~
In file included from include/uapi/linux/posix_types.h:5,
from include/uapi/linux/types.h:14,
from include/linux/types.h:6,
from include/linux/kasan-checks.h:5,
from include/asm-generic/rwonce.h:26,
from ./arch/arm/include/generated/asm/rwonce.h:1,
from include/linux/compiler.h:247,
from include/linux/build_bug.h:5:
>> include/linux/stddef.h:16:33: error: invalid use of undefined type 'struct nvec_led'
16 | #define offsetof(TYPE, MEMBER) __builtin_offsetof(TYPE, MEMBER)
| ^~~~~~~~~~~~~~~~~~
include/linux/container_of.h:23:28: note: in expansion of macro 'offsetof'
23 | ((type *)(__mptr - offsetof(type, member))); })
| ^~~~~~~~
drivers/staging/nvec/nvec_paz00.c:19:16: note: in expansion of macro 'container_of'
19 | return container_of(led_cdev, struct nvec_led, cdev);
| ^~~~~~~~~~~~
drivers/staging/nvec/nvec_paz00.c:20:1: error: control reaches end of non-void function [-Werror=return-type]
20 | }
| ^
cc1: some warnings being treated as errors
vim +20 include/linux/container_of.h
d2a8ebbf8192b8 Andy Shevchenko 2021-11-08 9
d2a8ebbf8192b8 Andy Shevchenko 2021-11-08 10 /**
d2a8ebbf8192b8 Andy Shevchenko 2021-11-08 11 * container_of - cast a member of a structure out to the containing structure
d2a8ebbf8192b8 Andy Shevchenko 2021-11-08 12 * @ptr: the pointer to the member.
d2a8ebbf8192b8 Andy Shevchenko 2021-11-08 13 * @type: the type of the container struct this is embedded in.
d2a8ebbf8192b8 Andy Shevchenko 2021-11-08 14 * @member: the name of the member within the struct.
d2a8ebbf8192b8 Andy Shevchenko 2021-11-08 15 *
7376e561fd2e01 Sakari Ailus 2022-10-24 16 * WARNING: any const qualifier of @ptr is lost.
d2a8ebbf8192b8 Andy Shevchenko 2021-11-08 17 */
d2a8ebbf8192b8 Andy Shevchenko 2021-11-08 18 #define container_of(ptr, type, member) ({ \
d2a8ebbf8192b8 Andy Shevchenko 2021-11-08 19 void *__mptr = (void *)(ptr); \
e1edc277e6f6df Rasmus Villemoes 2021-11-08 @20 static_assert(__same_type(*(ptr), ((type *)0)->member) || \
e1edc277e6f6df Rasmus Villemoes 2021-11-08 21 __same_type(*(ptr), void), \
d2a8ebbf8192b8 Andy Shevchenko 2021-11-08 22 "pointer type mismatch in container_of()"); \
d2a8ebbf8192b8 Andy Shevchenko 2021-11-08 23 ((type *)(__mptr - offsetof(type, member))); })
d2a8ebbf8192b8 Andy Shevchenko 2021-11-08 24
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests
^ permalink raw reply [flat|nested] 6+ messages in thread