Re: [PATCH 1/2] devres: provide devm_kstrdup_const()
On Mon, Aug 27, 2018 at 04:28:55PM +0200, Bartosz Golaszewski wrote:
> 2018-08-27 12:33 GMT+02:00 Mike Rapoport :
> > On Mon, Aug 27, 2018 at 10:21:00AM +0200, Bartosz Golaszewski wrote:
> >> Provide a resource managed version of kstrdup_const(). This variant
> >> internally calls devm_kstrdup() on pointers that are outside of
> >> .rodata section. Also provide a corresponding version of devm_kfree().
> >>
> >> Signed-off-by: Bartosz Golaszewski
> >> ---
> >> include/linux/device.h | 2 ++
> >> mm/util.c | 35 +++
> >> 2 files changed, 37 insertions(+)
> >>
> >> diff --git a/include/linux/device.h b/include/linux/device.h
> >> index 8f882549edee..f8f5982d26b2 100644
> >> --- a/include/linux/device.h
> >> +++ b/include/linux/device.h
> >> @@ -693,7 +693,9 @@ static inline void *devm_kcalloc(struct device *dev,
> >> return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
> >> }
> >> extern void devm_kfree(struct device *dev, void *p);
> >> +extern void devm_kfree_const(struct device *dev, void *p);
> >> extern char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp)
> >> __malloc;
> >> +extern char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t
> >> gfp);
> >> extern void *devm_kmemdup(struct device *dev, const void *src, size_t len,
> >> gfp_t gfp);
> >>
> >> diff --git a/mm/util.c b/mm/util.c
> >> index d2890a407332..6d1f41b5775e 100644
> >> --- a/mm/util.c
> >> +++ b/mm/util.c
[ ... ]
> >> + * Strings allocated by devm_kstrdup_const will be automatically freed
> >> when
> >> + * the associated device is detached.
> >> + */
> >> +char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp)
> >> +{
> >> + if (is_kernel_rodata((unsigned long)s))
> >> + return s;
> >> +
> >> + return devm_kstrdup(dev, s, gfp);
> >> +}
> >> +EXPORT_SYMBOL(devm_kstrdup_const);
> >> +
> >
> > The devm_ variants seem to belong to drivers/base/devres.c rather than
> > mm/util.c
> >
>
> Not all devm_ variants live in drivers/base/devres.c, many subsystems
> implement them locally. In this case we need to choose between
> exporting is_kernel_rodata() and putting devm_kstrdup_const() in
> mm/util.c. I chose the latter, since it's cleaner.
I rather think that moving is_kernel_rodata() to
include/asm-generic/sections.h and having devm_kstrdup_const() next to
devm_kstrdup() would be cleaner.
> Bart
>
--
Sincerely yours,
Mike.
Re: [PATCH 1/2] devres: provide devm_kstrdup_const()
On Mon, Aug 27, 2018 at 04:28:55PM +0200, Bartosz Golaszewski wrote:
> 2018-08-27 12:33 GMT+02:00 Mike Rapoport :
> > On Mon, Aug 27, 2018 at 10:21:00AM +0200, Bartosz Golaszewski wrote:
> >> Provide a resource managed version of kstrdup_const(). This variant
> >> internally calls devm_kstrdup() on pointers that are outside of
> >> .rodata section. Also provide a corresponding version of devm_kfree().
> >>
> >> Signed-off-by: Bartosz Golaszewski
> >> ---
> >> include/linux/device.h | 2 ++
> >> mm/util.c | 35 +++
> >> 2 files changed, 37 insertions(+)
> >>
> >> diff --git a/include/linux/device.h b/include/linux/device.h
> >> index 8f882549edee..f8f5982d26b2 100644
> >> --- a/include/linux/device.h
> >> +++ b/include/linux/device.h
> >> @@ -693,7 +693,9 @@ static inline void *devm_kcalloc(struct device *dev,
> >> return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
> >> }
> >> extern void devm_kfree(struct device *dev, void *p);
> >> +extern void devm_kfree_const(struct device *dev, void *p);
> >> extern char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp)
> >> __malloc;
> >> +extern char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t
> >> gfp);
> >> extern void *devm_kmemdup(struct device *dev, const void *src, size_t len,
> >> gfp_t gfp);
> >>
> >> diff --git a/mm/util.c b/mm/util.c
> >> index d2890a407332..6d1f41b5775e 100644
> >> --- a/mm/util.c
> >> +++ b/mm/util.c
[ ... ]
> >> + * Strings allocated by devm_kstrdup_const will be automatically freed
> >> when
> >> + * the associated device is detached.
> >> + */
> >> +char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp)
> >> +{
> >> + if (is_kernel_rodata((unsigned long)s))
> >> + return s;
> >> +
> >> + return devm_kstrdup(dev, s, gfp);
> >> +}
> >> +EXPORT_SYMBOL(devm_kstrdup_const);
> >> +
> >
> > The devm_ variants seem to belong to drivers/base/devres.c rather than
> > mm/util.c
> >
>
> Not all devm_ variants live in drivers/base/devres.c, many subsystems
> implement them locally. In this case we need to choose between
> exporting is_kernel_rodata() and putting devm_kstrdup_const() in
> mm/util.c. I chose the latter, since it's cleaner.
I rather think that moving is_kernel_rodata() to
include/asm-generic/sections.h and having devm_kstrdup_const() next to
devm_kstrdup() would be cleaner.
> Bart
>
--
Sincerely yours,
Mike.
Re: [PATCH 1/2] devres: provide devm_kstrdup_const()
2018-08-27 12:33 GMT+02:00 Mike Rapoport :
> On Mon, Aug 27, 2018 at 10:21:00AM +0200, Bartosz Golaszewski wrote:
>> Provide a resource managed version of kstrdup_const(). This variant
>> internally calls devm_kstrdup() on pointers that are outside of
>> .rodata section. Also provide a corresponding version of devm_kfree().
>>
>> Signed-off-by: Bartosz Golaszewski
>> ---
>> include/linux/device.h | 2 ++
>> mm/util.c | 35 +++
>> 2 files changed, 37 insertions(+)
>>
>> diff --git a/include/linux/device.h b/include/linux/device.h
>> index 8f882549edee..f8f5982d26b2 100644
>> --- a/include/linux/device.h
>> +++ b/include/linux/device.h
>> @@ -693,7 +693,9 @@ static inline void *devm_kcalloc(struct device *dev,
>> return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
>> }
>> extern void devm_kfree(struct device *dev, void *p);
>> +extern void devm_kfree_const(struct device *dev, void *p);
>> extern char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp)
>> __malloc;
>> +extern char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t
>> gfp);
>> extern void *devm_kmemdup(struct device *dev, const void *src, size_t len,
>> gfp_t gfp);
>>
>> diff --git a/mm/util.c b/mm/util.c
>> index d2890a407332..6d1f41b5775e 100644
>> --- a/mm/util.c
>> +++ b/mm/util.c
>> @@ -39,6 +39,20 @@ void kfree_const(const void *x)
>> }
>> EXPORT_SYMBOL(kfree_const);
>>
>> +/**
>> + * devm_kfree_const - Resource managed conditional kfree
>> + * @dev: device this memory belongs to
>> + * @p: memory to free
>> + *
>> + * Function calls devm_kfree only if @p is not in .rodata section.
>> + */
>> +void devm_kfree_const(struct device *dev, void *p)
>> +{
>> + if (!is_kernel_rodata((unsigned long)p))
>> + devm_kfree(dev, p);
>> +}
>> +EXPORT_SYMBOL(devm_kfree_const);
>> +
>> /**
>> * kstrdup - allocate space for and copy an existing string
>> * @s: the string to duplicate
>> @@ -78,6 +92,27 @@ const char *kstrdup_const(const char *s, gfp_t gfp)
>> }
>> EXPORT_SYMBOL(kstrdup_const);
>>
>> +/**
>> + * devm_kstrdup_const - resource managed conditional string duplication
>> + * @dev: device for which to duplicate the string
>> + * @s: the string to duplicate
>> + * @gfp: the GFP mask used in the kmalloc() call when allocating memory
>> + *
>> + * Function returns source string if it is in .rodata section otherwise it
>> + * fallbacks to devm_kstrdup.
>
> Please make it proper "Returns:" description and move to the end of the
> comment. See Documentation/doc-guide/kernel-doc.rst.
>
Sure.
>> + * Strings allocated by devm_kstrdup_const will be automatically freed when
>> + * the associated device is detached.
>> + */
>> +char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp)
>> +{
>> + if (is_kernel_rodata((unsigned long)s))
>> + return s;
>> +
>> + return devm_kstrdup(dev, s, gfp);
>> +}
>> +EXPORT_SYMBOL(devm_kstrdup_const);
>> +
>
> The devm_ variants seem to belong to drivers/base/devres.c rather than
> mm/util.c
>
Not all devm_ variants live in drivers/base/devres.c, many subsystems
implement them locally. In this case we need to choose between
exporting is_kernel_rodata() and putting devm_kstrdup_const() in
mm/util.c. I chose the latter, since it's cleaner.
Bart
>> /**
>> * kstrndup - allocate space for and copy an existing string
>> * @s: the string to duplicate
>> --
>> 2.18.0
>>
>
> --
> Sincerely yours,
> Mike.
>
Re: [PATCH 1/2] devres: provide devm_kstrdup_const()
2018-08-27 12:33 GMT+02:00 Mike Rapoport :
> On Mon, Aug 27, 2018 at 10:21:00AM +0200, Bartosz Golaszewski wrote:
>> Provide a resource managed version of kstrdup_const(). This variant
>> internally calls devm_kstrdup() on pointers that are outside of
>> .rodata section. Also provide a corresponding version of devm_kfree().
>>
>> Signed-off-by: Bartosz Golaszewski
>> ---
>> include/linux/device.h | 2 ++
>> mm/util.c | 35 +++
>> 2 files changed, 37 insertions(+)
>>
>> diff --git a/include/linux/device.h b/include/linux/device.h
>> index 8f882549edee..f8f5982d26b2 100644
>> --- a/include/linux/device.h
>> +++ b/include/linux/device.h
>> @@ -693,7 +693,9 @@ static inline void *devm_kcalloc(struct device *dev,
>> return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
>> }
>> extern void devm_kfree(struct device *dev, void *p);
>> +extern void devm_kfree_const(struct device *dev, void *p);
>> extern char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp)
>> __malloc;
>> +extern char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t
>> gfp);
>> extern void *devm_kmemdup(struct device *dev, const void *src, size_t len,
>> gfp_t gfp);
>>
>> diff --git a/mm/util.c b/mm/util.c
>> index d2890a407332..6d1f41b5775e 100644
>> --- a/mm/util.c
>> +++ b/mm/util.c
>> @@ -39,6 +39,20 @@ void kfree_const(const void *x)
>> }
>> EXPORT_SYMBOL(kfree_const);
>>
>> +/**
>> + * devm_kfree_const - Resource managed conditional kfree
>> + * @dev: device this memory belongs to
>> + * @p: memory to free
>> + *
>> + * Function calls devm_kfree only if @p is not in .rodata section.
>> + */
>> +void devm_kfree_const(struct device *dev, void *p)
>> +{
>> + if (!is_kernel_rodata((unsigned long)p))
>> + devm_kfree(dev, p);
>> +}
>> +EXPORT_SYMBOL(devm_kfree_const);
>> +
>> /**
>> * kstrdup - allocate space for and copy an existing string
>> * @s: the string to duplicate
>> @@ -78,6 +92,27 @@ const char *kstrdup_const(const char *s, gfp_t gfp)
>> }
>> EXPORT_SYMBOL(kstrdup_const);
>>
>> +/**
>> + * devm_kstrdup_const - resource managed conditional string duplication
>> + * @dev: device for which to duplicate the string
>> + * @s: the string to duplicate
>> + * @gfp: the GFP mask used in the kmalloc() call when allocating memory
>> + *
>> + * Function returns source string if it is in .rodata section otherwise it
>> + * fallbacks to devm_kstrdup.
>
> Please make it proper "Returns:" description and move to the end of the
> comment. See Documentation/doc-guide/kernel-doc.rst.
>
Sure.
>> + * Strings allocated by devm_kstrdup_const will be automatically freed when
>> + * the associated device is detached.
>> + */
>> +char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp)
>> +{
>> + if (is_kernel_rodata((unsigned long)s))
>> + return s;
>> +
>> + return devm_kstrdup(dev, s, gfp);
>> +}
>> +EXPORT_SYMBOL(devm_kstrdup_const);
>> +
>
> The devm_ variants seem to belong to drivers/base/devres.c rather than
> mm/util.c
>
Not all devm_ variants live in drivers/base/devres.c, many subsystems
implement them locally. In this case we need to choose between
exporting is_kernel_rodata() and putting devm_kstrdup_const() in
mm/util.c. I chose the latter, since it's cleaner.
Bart
>> /**
>> * kstrndup - allocate space for and copy an existing string
>> * @s: the string to duplicate
>> --
>> 2.18.0
>>
>
> --
> Sincerely yours,
> Mike.
>
Re: [PATCH 1/2] devres: provide devm_kstrdup_const()
Hi Bartosz,
I love your patch! Perhaps something to improve:
[auto build test WARNING on clk/clk-next]
[also build test WARNING on v4.19-rc1 next-20180827]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system]
url:
https://github.com/0day-ci/linux/commits/Bartosz-Golaszewski/devres-provide-devm_kstrdup_const/20180827-162336
base: https://git.kernel.org/pub/scm/linux/kernel/git/clk/linux.git clk-next
config: powerpc-mpc836x_mds_defconfig (attached as .config)
compiler: powerpc-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
wget
https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O
~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
GCC_VERSION=7.2.0 make.cross ARCH=powerpc
All warnings (new ones prefixed by >>):
mm/util.c: In function 'devm_kstrdup_const':
>> mm/util.c:110:10: warning: return discards 'const' qualifier from pointer
>> target type [-Wdiscarded-qualifiers]
return s;
^
vim +/const +110 mm/util.c
94
95 /**
96 * devm_kstrdup_const - resource managed conditional string duplication
97 * @dev: device for which to duplicate the string
98 * @s: the string to duplicate
99 * @gfp: the GFP mask used in the kmalloc() call when allocating memory
100 *
101 * Function returns source string if it is in .rodata section otherwise
it
102 * fallbacks to devm_kstrdup.
103 *
104 * Strings allocated by devm_kstrdup_const will be automatically freed
when
105 * the associated device is detached.
106 */
107 char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp)
108 {
109 if (is_kernel_rodata((unsigned long)s))
> 110 return s;
111
112 return devm_kstrdup(dev, s, gfp);
113 }
114 EXPORT_SYMBOL(devm_kstrdup_const);
115
---
0-DAY kernel test infrastructureOpen Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
.config.gz
Description: application/gzip
Re: [PATCH 1/2] devres: provide devm_kstrdup_const()
Hi Bartosz,
I love your patch! Perhaps something to improve:
[auto build test WARNING on clk/clk-next]
[also build test WARNING on v4.19-rc1 next-20180827]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system]
url:
https://github.com/0day-ci/linux/commits/Bartosz-Golaszewski/devres-provide-devm_kstrdup_const/20180827-162336
base: https://git.kernel.org/pub/scm/linux/kernel/git/clk/linux.git clk-next
config: powerpc-mpc836x_mds_defconfig (attached as .config)
compiler: powerpc-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
wget
https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O
~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
GCC_VERSION=7.2.0 make.cross ARCH=powerpc
All warnings (new ones prefixed by >>):
mm/util.c: In function 'devm_kstrdup_const':
>> mm/util.c:110:10: warning: return discards 'const' qualifier from pointer
>> target type [-Wdiscarded-qualifiers]
return s;
^
vim +/const +110 mm/util.c
94
95 /**
96 * devm_kstrdup_const - resource managed conditional string duplication
97 * @dev: device for which to duplicate the string
98 * @s: the string to duplicate
99 * @gfp: the GFP mask used in the kmalloc() call when allocating memory
100 *
101 * Function returns source string if it is in .rodata section otherwise
it
102 * fallbacks to devm_kstrdup.
103 *
104 * Strings allocated by devm_kstrdup_const will be automatically freed
when
105 * the associated device is detached.
106 */
107 char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp)
108 {
109 if (is_kernel_rodata((unsigned long)s))
> 110 return s;
111
112 return devm_kstrdup(dev, s, gfp);
113 }
114 EXPORT_SYMBOL(devm_kstrdup_const);
115
---
0-DAY kernel test infrastructureOpen Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
.config.gz
Description: application/gzip
Re: [PATCH 1/2] devres: provide devm_kstrdup_const()
On Mon, Aug 27, 2018 at 10:21:00AM +0200, Bartosz Golaszewski wrote:
> Provide a resource managed version of kstrdup_const(). This variant
> internally calls devm_kstrdup() on pointers that are outside of
> .rodata section. Also provide a corresponding version of devm_kfree().
>
> Signed-off-by: Bartosz Golaszewski
> ---
> include/linux/device.h | 2 ++
> mm/util.c | 35 +++
> 2 files changed, 37 insertions(+)
>
> diff --git a/include/linux/device.h b/include/linux/device.h
> index 8f882549edee..f8f5982d26b2 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -693,7 +693,9 @@ static inline void *devm_kcalloc(struct device *dev,
> return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
> }
> extern void devm_kfree(struct device *dev, void *p);
> +extern void devm_kfree_const(struct device *dev, void *p);
> extern char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp)
> __malloc;
> +extern char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t
> gfp);
> extern void *devm_kmemdup(struct device *dev, const void *src, size_t len,
> gfp_t gfp);
>
> diff --git a/mm/util.c b/mm/util.c
> index d2890a407332..6d1f41b5775e 100644
> --- a/mm/util.c
> +++ b/mm/util.c
> @@ -39,6 +39,20 @@ void kfree_const(const void *x)
> }
> EXPORT_SYMBOL(kfree_const);
>
> +/**
> + * devm_kfree_const - Resource managed conditional kfree
> + * @dev: device this memory belongs to
> + * @p: memory to free
> + *
> + * Function calls devm_kfree only if @p is not in .rodata section.
> + */
> +void devm_kfree_const(struct device *dev, void *p)
> +{
> + if (!is_kernel_rodata((unsigned long)p))
> + devm_kfree(dev, p);
> +}
> +EXPORT_SYMBOL(devm_kfree_const);
> +
> /**
> * kstrdup - allocate space for and copy an existing string
> * @s: the string to duplicate
> @@ -78,6 +92,27 @@ const char *kstrdup_const(const char *s, gfp_t gfp)
> }
> EXPORT_SYMBOL(kstrdup_const);
>
> +/**
> + * devm_kstrdup_const - resource managed conditional string duplication
> + * @dev: device for which to duplicate the string
> + * @s: the string to duplicate
> + * @gfp: the GFP mask used in the kmalloc() call when allocating memory
> + *
> + * Function returns source string if it is in .rodata section otherwise it
> + * fallbacks to devm_kstrdup.
Please make it proper "Returns:" description and move to the end of the
comment. See Documentation/doc-guide/kernel-doc.rst.
> + * Strings allocated by devm_kstrdup_const will be automatically freed when
> + * the associated device is detached.
> + */
> +char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp)
> +{
> + if (is_kernel_rodata((unsigned long)s))
> + return s;
> +
> + return devm_kstrdup(dev, s, gfp);
> +}
> +EXPORT_SYMBOL(devm_kstrdup_const);
> +
The devm_ variants seem to belong to drivers/base/devres.c rather than
mm/util.c
> /**
> * kstrndup - allocate space for and copy an existing string
> * @s: the string to duplicate
> --
> 2.18.0
>
--
Sincerely yours,
Mike.
Re: [PATCH 1/2] devres: provide devm_kstrdup_const()
On Mon, Aug 27, 2018 at 10:21:00AM +0200, Bartosz Golaszewski wrote:
> Provide a resource managed version of kstrdup_const(). This variant
> internally calls devm_kstrdup() on pointers that are outside of
> .rodata section. Also provide a corresponding version of devm_kfree().
>
> Signed-off-by: Bartosz Golaszewski
> ---
> include/linux/device.h | 2 ++
> mm/util.c | 35 +++
> 2 files changed, 37 insertions(+)
>
> diff --git a/include/linux/device.h b/include/linux/device.h
> index 8f882549edee..f8f5982d26b2 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -693,7 +693,9 @@ static inline void *devm_kcalloc(struct device *dev,
> return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
> }
> extern void devm_kfree(struct device *dev, void *p);
> +extern void devm_kfree_const(struct device *dev, void *p);
> extern char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp)
> __malloc;
> +extern char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t
> gfp);
> extern void *devm_kmemdup(struct device *dev, const void *src, size_t len,
> gfp_t gfp);
>
> diff --git a/mm/util.c b/mm/util.c
> index d2890a407332..6d1f41b5775e 100644
> --- a/mm/util.c
> +++ b/mm/util.c
> @@ -39,6 +39,20 @@ void kfree_const(const void *x)
> }
> EXPORT_SYMBOL(kfree_const);
>
> +/**
> + * devm_kfree_const - Resource managed conditional kfree
> + * @dev: device this memory belongs to
> + * @p: memory to free
> + *
> + * Function calls devm_kfree only if @p is not in .rodata section.
> + */
> +void devm_kfree_const(struct device *dev, void *p)
> +{
> + if (!is_kernel_rodata((unsigned long)p))
> + devm_kfree(dev, p);
> +}
> +EXPORT_SYMBOL(devm_kfree_const);
> +
> /**
> * kstrdup - allocate space for and copy an existing string
> * @s: the string to duplicate
> @@ -78,6 +92,27 @@ const char *kstrdup_const(const char *s, gfp_t gfp)
> }
> EXPORT_SYMBOL(kstrdup_const);
>
> +/**
> + * devm_kstrdup_const - resource managed conditional string duplication
> + * @dev: device for which to duplicate the string
> + * @s: the string to duplicate
> + * @gfp: the GFP mask used in the kmalloc() call when allocating memory
> + *
> + * Function returns source string if it is in .rodata section otherwise it
> + * fallbacks to devm_kstrdup.
Please make it proper "Returns:" description and move to the end of the
comment. See Documentation/doc-guide/kernel-doc.rst.
> + * Strings allocated by devm_kstrdup_const will be automatically freed when
> + * the associated device is detached.
> + */
> +char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp)
> +{
> + if (is_kernel_rodata((unsigned long)s))
> + return s;
> +
> + return devm_kstrdup(dev, s, gfp);
> +}
> +EXPORT_SYMBOL(devm_kstrdup_const);
> +
The devm_ variants seem to belong to drivers/base/devres.c rather than
mm/util.c
> /**
> * kstrndup - allocate space for and copy an existing string
> * @s: the string to duplicate
> --
> 2.18.0
>
--
Sincerely yours,
Mike.
Re: [PATCH 1/2] devres: provide devm_kstrdup_const()
2018-08-27 10:42 GMT+02:00 Joe Perches :
> On Mon, 2018-08-27 at 10:21 +0200, Bartosz Golaszewski wrote:
>> Provide a resource managed version of kstrdup_const(). This variant
>> internally calls devm_kstrdup() on pointers that are outside of
>> .rodata section. Also provide a corresponding version of devm_kfree().
> []
>> diff --git a/mm/util.c b/mm/util.c
> []
>> /**
>> * kstrdup - allocate space for and copy an existing string
>> * @s: the string to duplicate
>> @@ -78,6 +92,27 @@ const char *kstrdup_const(const char *s, gfp_t gfp)
>> }
>> EXPORT_SYMBOL(kstrdup_const);
>>
>> +/**
>> + * devm_kstrdup_const - resource managed conditional string duplication
>> + * @dev: device for which to duplicate the string
>> + * @s: the string to duplicate
>> + * @gfp: the GFP mask used in the kmalloc() call when allocating memory
>> + *
>> + * Function returns source string if it is in .rodata section otherwise it
>> + * fallbacks to devm_kstrdup.
>> + *
>> + * Strings allocated by devm_kstrdup_const will be automatically freed when
>> + * the associated device is detached.
>> + */
>> +char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp)
>> +{
>> + if (is_kernel_rodata((unsigned long)s))
>> + return s;
>> +
>> + return devm_kstrdup(dev, s, gfp);
>> +}
>> +EXPORT_SYMBOL(devm_kstrdup_const);
>
> Doesn't this lose constness and don't you get
> a compiler warning here?
>
Yes it does but for some reason gcc 6.3 didn't complain...
> The kstrdup_const function returns a const char *,
> why shouldn't this?
>
It probably should, I'll fix it for v2.
Bart
Re: [PATCH 1/2] devres: provide devm_kstrdup_const()
2018-08-27 10:42 GMT+02:00 Joe Perches :
> On Mon, 2018-08-27 at 10:21 +0200, Bartosz Golaszewski wrote:
>> Provide a resource managed version of kstrdup_const(). This variant
>> internally calls devm_kstrdup() on pointers that are outside of
>> .rodata section. Also provide a corresponding version of devm_kfree().
> []
>> diff --git a/mm/util.c b/mm/util.c
> []
>> /**
>> * kstrdup - allocate space for and copy an existing string
>> * @s: the string to duplicate
>> @@ -78,6 +92,27 @@ const char *kstrdup_const(const char *s, gfp_t gfp)
>> }
>> EXPORT_SYMBOL(kstrdup_const);
>>
>> +/**
>> + * devm_kstrdup_const - resource managed conditional string duplication
>> + * @dev: device for which to duplicate the string
>> + * @s: the string to duplicate
>> + * @gfp: the GFP mask used in the kmalloc() call when allocating memory
>> + *
>> + * Function returns source string if it is in .rodata section otherwise it
>> + * fallbacks to devm_kstrdup.
>> + *
>> + * Strings allocated by devm_kstrdup_const will be automatically freed when
>> + * the associated device is detached.
>> + */
>> +char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp)
>> +{
>> + if (is_kernel_rodata((unsigned long)s))
>> + return s;
>> +
>> + return devm_kstrdup(dev, s, gfp);
>> +}
>> +EXPORT_SYMBOL(devm_kstrdup_const);
>
> Doesn't this lose constness and don't you get
> a compiler warning here?
>
Yes it does but for some reason gcc 6.3 didn't complain...
> The kstrdup_const function returns a const char *,
> why shouldn't this?
>
It probably should, I'll fix it for v2.
Bart
Re: [PATCH 1/2] devres: provide devm_kstrdup_const()
On Mon, 2018-08-27 at 10:21 +0200, Bartosz Golaszewski wrote:
> Provide a resource managed version of kstrdup_const(). This variant
> internally calls devm_kstrdup() on pointers that are outside of
> .rodata section. Also provide a corresponding version of devm_kfree().
[]
> diff --git a/mm/util.c b/mm/util.c
[]
> /**
> * kstrdup - allocate space for and copy an existing string
> * @s: the string to duplicate
> @@ -78,6 +92,27 @@ const char *kstrdup_const(const char *s, gfp_t gfp)
> }
> EXPORT_SYMBOL(kstrdup_const);
>
> +/**
> + * devm_kstrdup_const - resource managed conditional string duplication
> + * @dev: device for which to duplicate the string
> + * @s: the string to duplicate
> + * @gfp: the GFP mask used in the kmalloc() call when allocating memory
> + *
> + * Function returns source string if it is in .rodata section otherwise it
> + * fallbacks to devm_kstrdup.
> + *
> + * Strings allocated by devm_kstrdup_const will be automatically freed when
> + * the associated device is detached.
> + */
> +char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp)
> +{
> + if (is_kernel_rodata((unsigned long)s))
> + return s;
> +
> + return devm_kstrdup(dev, s, gfp);
> +}
> +EXPORT_SYMBOL(devm_kstrdup_const);
Doesn't this lose constness and don't you get
a compiler warning here?
The kstrdup_const function returns a const char *,
why shouldn't this?
Re: [PATCH 1/2] devres: provide devm_kstrdup_const()
On Mon, 2018-08-27 at 10:21 +0200, Bartosz Golaszewski wrote:
> Provide a resource managed version of kstrdup_const(). This variant
> internally calls devm_kstrdup() on pointers that are outside of
> .rodata section. Also provide a corresponding version of devm_kfree().
[]
> diff --git a/mm/util.c b/mm/util.c
[]
> /**
> * kstrdup - allocate space for and copy an existing string
> * @s: the string to duplicate
> @@ -78,6 +92,27 @@ const char *kstrdup_const(const char *s, gfp_t gfp)
> }
> EXPORT_SYMBOL(kstrdup_const);
>
> +/**
> + * devm_kstrdup_const - resource managed conditional string duplication
> + * @dev: device for which to duplicate the string
> + * @s: the string to duplicate
> + * @gfp: the GFP mask used in the kmalloc() call when allocating memory
> + *
> + * Function returns source string if it is in .rodata section otherwise it
> + * fallbacks to devm_kstrdup.
> + *
> + * Strings allocated by devm_kstrdup_const will be automatically freed when
> + * the associated device is detached.
> + */
> +char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp)
> +{
> + if (is_kernel_rodata((unsigned long)s))
> + return s;
> +
> + return devm_kstrdup(dev, s, gfp);
> +}
> +EXPORT_SYMBOL(devm_kstrdup_const);
Doesn't this lose constness and don't you get
a compiler warning here?
The kstrdup_const function returns a const char *,
why shouldn't this?
