diff mbox series

[v4,1/4] devres: Provide krealloc_array

Message ID 20230509094942.396150-2-james.clark@arm.com (mailing list archive)
State Not Applicable
Headers show
Series devres: Provide krealloc_array | expand

Commit Message

James Clark May 9, 2023, 9:49 a.m. UTC
There is no krealloc_array equivalent in devres. Users would have to
do their own multiplication overflow check so provide one.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: James Clark <james.clark@arm.com>
---
 Documentation/driver-api/driver-model/devres.rst |  1 +
 include/linux/device.h                           | 11 +++++++++++
 2 files changed, 12 insertions(+)

Comments

Greg KH May 13, 2023, 11:04 a.m. UTC | #1
On Tue, May 09, 2023 at 10:49:38AM +0100, James Clark wrote:
> There is no krealloc_array equivalent in devres. Users would have to
> do their own multiplication overflow check so provide one.
> 
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Signed-off-by: James Clark <james.clark@arm.com>
> ---
>  Documentation/driver-api/driver-model/devres.rst |  1 +
>  include/linux/device.h                           | 11 +++++++++++
>  2 files changed, 12 insertions(+)
> 
> diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst
> index 4249eb4239e0..8be086b3f829 100644
> --- a/Documentation/driver-api/driver-model/devres.rst
> +++ b/Documentation/driver-api/driver-model/devres.rst
> @@ -364,6 +364,7 @@ MEM
>    devm_kmalloc_array()
>    devm_kmemdup()
>    devm_krealloc()
> +  devm_krealloc_array()
>    devm_kstrdup()
>    devm_kstrdup_const()
>    devm_kvasprintf()
> diff --git a/include/linux/device.h b/include/linux/device.h
> index 472dd24d4823..58f4f5948edb 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -223,6 +223,17 @@ static inline void *devm_kcalloc(struct device *dev,
>  {
>  	return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
>  }
> +static inline __realloc_size(3, 4) void * __must_check

Shouldn't you have a blank line before this one?

> +devm_krealloc_array(struct device *dev, void *p, size_t new_n, size_t new_size, gfp_t flags)
> +{
> +	size_t bytes;
> +
> +	if (unlikely(check_mul_overflow(new_n, new_size, &bytes)))
> +		return NULL;
> +
> +	return devm_krealloc(dev, p, bytes, flags);
> +}

I dislike how we have to keep copying the "real" functions (i.e.
krealloc_array) into something like this, but I can't think of a better
way to do it.

thanks,

greg k-h
James Clark May 15, 2023, 7:55 a.m. UTC | #2
On 13/05/2023 12:04, Greg KH wrote:
> On Tue, May 09, 2023 at 10:49:38AM +0100, James Clark wrote:
>> There is no krealloc_array equivalent in devres. Users would have to
>> do their own multiplication overflow check so provide one.
>>
>> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>> Signed-off-by: James Clark <james.clark@arm.com>
>> ---
>>  Documentation/driver-api/driver-model/devres.rst |  1 +
>>  include/linux/device.h                           | 11 +++++++++++
>>  2 files changed, 12 insertions(+)
>>
>> diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst
>> index 4249eb4239e0..8be086b3f829 100644
>> --- a/Documentation/driver-api/driver-model/devres.rst
>> +++ b/Documentation/driver-api/driver-model/devres.rst
>> @@ -364,6 +364,7 @@ MEM
>>    devm_kmalloc_array()
>>    devm_kmemdup()
>>    devm_krealloc()
>> +  devm_krealloc_array()
>>    devm_kstrdup()
>>    devm_kstrdup_const()
>>    devm_kvasprintf()
>> diff --git a/include/linux/device.h b/include/linux/device.h
>> index 472dd24d4823..58f4f5948edb 100644
>> --- a/include/linux/device.h
>> +++ b/include/linux/device.h
>> @@ -223,6 +223,17 @@ static inline void *devm_kcalloc(struct device *dev,
>>  {
>>  	return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
>>  }
>> +static inline __realloc_size(3, 4) void * __must_check
> 
> Shouldn't you have a blank line before this one?

I was going for consistency with the rest of this section which doesn't
have newlines between the functions for some reason. I can add one and
resubmit but it might look a bit out of place?

> 
>> +devm_krealloc_array(struct device *dev, void *p, size_t new_n, size_t new_size, gfp_t flags)
>> +{
>> +	size_t bytes;
>> +
>> +	if (unlikely(check_mul_overflow(new_n, new_size, &bytes)))
>> +		return NULL;
>> +
>> +	return devm_krealloc(dev, p, bytes, flags);
>> +}
> 
> I dislike how we have to keep copying the "real" functions (i.e.
> krealloc_array) into something like this, but I can't think of a better
> way to do it.
> 

Maybe something could be done with some macro magic, but it would
probably end up being worse than just copying them and would affect the
real ones as well. So yeah I can't think of any easy gains either.

Thanks
James

> thanks,
> 
> greg k-h
Greg KH May 15, 2023, 11:55 a.m. UTC | #3
On Mon, May 15, 2023 at 08:55:33AM +0100, James Clark wrote:
> 
> 
> On 13/05/2023 12:04, Greg KH wrote:
> > On Tue, May 09, 2023 at 10:49:38AM +0100, James Clark wrote:
> >> There is no krealloc_array equivalent in devres. Users would have to
> >> do their own multiplication overflow check so provide one.
> >>
> >> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> >> Signed-off-by: James Clark <james.clark@arm.com>
> >> ---
> >>  Documentation/driver-api/driver-model/devres.rst |  1 +
> >>  include/linux/device.h                           | 11 +++++++++++
> >>  2 files changed, 12 insertions(+)
> >>
> >> diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst
> >> index 4249eb4239e0..8be086b3f829 100644
> >> --- a/Documentation/driver-api/driver-model/devres.rst
> >> +++ b/Documentation/driver-api/driver-model/devres.rst
> >> @@ -364,6 +364,7 @@ MEM
> >>    devm_kmalloc_array()
> >>    devm_kmemdup()
> >>    devm_krealloc()
> >> +  devm_krealloc_array()
> >>    devm_kstrdup()
> >>    devm_kstrdup_const()
> >>    devm_kvasprintf()
> >> diff --git a/include/linux/device.h b/include/linux/device.h
> >> index 472dd24d4823..58f4f5948edb 100644
> >> --- a/include/linux/device.h
> >> +++ b/include/linux/device.h
> >> @@ -223,6 +223,17 @@ static inline void *devm_kcalloc(struct device *dev,
> >>  {
> >>  	return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
> >>  }
> >> +static inline __realloc_size(3, 4) void * __must_check
> > 
> > Shouldn't you have a blank line before this one?
> 
> I was going for consistency with the rest of this section which doesn't
> have newlines between the functions for some reason. I can add one and
> resubmit but it might look a bit out of place?

Ah, wasn't aware of that, given the lack of context.  So nevermind, it's
fine for now.

> >> +devm_krealloc_array(struct device *dev, void *p, size_t new_n, size_t new_size, gfp_t flags)
> >> +{
> >> +	size_t bytes;
> >> +
> >> +	if (unlikely(check_mul_overflow(new_n, new_size, &bytes)))
> >> +		return NULL;
> >> +
> >> +	return devm_krealloc(dev, p, bytes, flags);
> >> +}
> > 
> > I dislike how we have to keep copying the "real" functions (i.e.
> > krealloc_array) into something like this, but I can't think of a better
> > way to do it.
> > 
> 
> Maybe something could be done with some macro magic, but it would
> probably end up being worse than just copying them and would affect the
> real ones as well. So yeah I can't think of any easy gains either.

Ok, that's good.  Given a lack of objections from others, I'll just take
this through my driver core tree in a few days.

thanks,

greg k-h
diff mbox series

Patch

diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst
index 4249eb4239e0..8be086b3f829 100644
--- a/Documentation/driver-api/driver-model/devres.rst
+++ b/Documentation/driver-api/driver-model/devres.rst
@@ -364,6 +364,7 @@  MEM
   devm_kmalloc_array()
   devm_kmemdup()
   devm_krealloc()
+  devm_krealloc_array()
   devm_kstrdup()
   devm_kstrdup_const()
   devm_kvasprintf()
diff --git a/include/linux/device.h b/include/linux/device.h
index 472dd24d4823..58f4f5948edb 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -223,6 +223,17 @@  static inline void *devm_kcalloc(struct device *dev,
 {
 	return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
 }
+static inline __realloc_size(3, 4) void * __must_check
+devm_krealloc_array(struct device *dev, void *p, size_t new_n, size_t new_size, gfp_t flags)
+{
+	size_t bytes;
+
+	if (unlikely(check_mul_overflow(new_n, new_size, &bytes)))
+		return NULL;
+
+	return devm_krealloc(dev, p, bytes, flags);
+}
+
 void devm_kfree(struct device *dev, const void *p);
 char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp) __malloc;
 const char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp);