Hi Rik, Thanks for the information. I have coded it using uint32_t/ uint8_t data types. Should I consider it ok and should I change them to u32. Regards. Bhanu On Fri, Jul 4, 2008 at 6:14 PM, Rik van Riel <riel@xxxxxxxxxxx> wrote: > On Fri, 4 Jul 2008 17:38:25 -0700 > "bhanu nani" <bhanu.lnxnew@xxxxxxxxx> wrote: > >> if I have an ioctl that passes me some data in a structure which >> have to process and return the result as a field in the structure. >> Is it acceptable if I copy the entire structure with copy_to_user() >> instead of copying only the field with with put_user()? >> Because doing so I am overwriting the user data which is ok for my >> application but does Linux treat overwriting data in this fashion? > > This is a fairly normal thing. > > However, you will want to make sure that your data > structure is the same on 32 and 64 bit systems, > because someone may end up using it on a 64 bit > kernel in the future, with a 32 bit program. > > PPC64 tends to run 32 bit PPC programs, after all. > > So you'll want to make sure the data structure uses > data types that are the same on 32 and 64 bit (like > u32) instead of data types that change depending > on how the system is compiled (like unsigned long). > > -- > All rights reversed. > -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
