Re: [Xen-devel] [PATCH 4/4] xen: Introduce a xmemdup_bytes() helper

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 21/03/2020 22:19, Julien Grall wrote:
>> diff --git a/xen/include/xen/xmalloc.h b/xen/include/xen/xmalloc.h
>> index f515ceee2a..16979a117c 100644
>> --- a/xen/include/xen/xmalloc.h
>> +++ b/xen/include/xen/xmalloc.h
>> @@ -51,6 +51,17 @@
>>  #define xmalloc_bytes(_bytes) _xmalloc(_bytes, SMP_CACHE_BYTES)
>>  #define xzalloc_bytes(_bytes) _xzalloc(_bytes, SMP_CACHE_BYTES)
>>
>> +/* Allocate untyped storage and copying an existing instance. */
>> +#define xmemdup_bytes(_src, _nr)                \
>> +    ({                                          \
>> +        unsigned long nr_ = (_nr);              \
>> +        void *dst_ = xmalloc_bytes(nr_);        \
> The nr_ vs _nr is really confusing to read. Could you re-implement the
> function as a static inline?

I'd really prefer to, but sadly not.

That requires untangling headers sufficiently so we can include
string.h, to be able to use memcpy.  I don't have time at the moment to
sort that out.

~Andrew