----- On Jan 28, 2016, at 6:12 AM, heiko carstens [email protected] wrote:
> On Wed, Jan 27, 2016 at 10:47:37PM +0000, Mathieu Desnoyers wrote: >> ----- On Jan 27, 2016, at 5:11 PM, Josh Triplett [email protected] wrote: >> >> > On Wed, Jan 27, 2016 at 09:34:35PM +0000, Mathieu Desnoyers wrote: >> >> ----- On Jan 27, 2016, at 12:37 PM, Thomas Gleixner [email protected] >> >> wrote: >> >> >> >> > On Wed, 27 Jan 2016, Thomas Gleixner wrote: >> >> > >> >> >> On Wed, 27 Jan 2016, Mathieu Desnoyers wrote: >> >> >> > ----- On Jan 27, 2016, at 12:22 PM, Thomas Gleixner >> >> >> > [email protected] wrote: >> >> >> > Sounds fair. What is the recommended typing for "ptr" then ? >> >> >> > uint32_t ** or uint32_t * ? >> >> >> > >> >> >> > It would be expected to pass a "uint32_t *" for the set >> >> >> > operation, but the "get" operation requires a "uint32_t **". >> >> >> >> >> >> Well, you can't change the types depending on the opcode, so you need >> >> >> to stick >> >> >> with **. >> >> > >> >> > Alternatively you make it: >> >> > >> >> > (opcode, *newptr, **oldptr, flags); >> >> >> >> I'm tempted to stick to (opcode, **ptr, flags), because >> >> other syscalls that have "*newptr", "**oldptr" >> >> typically have them because they save the current state >> >> into oldptr, and set the new state, which is really >> >> not the case here. To eliminate any risk of confusion, >> >> I am tempted to keep a single "**ptr". >> >> >> >> Unless someone has a better idea... >> > >> > Either that or you could define it as "void *" and interpret it based on >> > flags, but that seems unfortunate; let's not imitate ioctl-style >> > typeless parameters. I'd stick with the double pointer and the current >> > behavior. >> >> Allright, will do! Thanks for the feedback :) > > Please don't forget that you also need to implement compat handling since > the size of the pointer that is being pointed to is only four bytes for > compat tasks. Oops, forgot about that. Will update my upcoming v3 to handle this properly. Well spotted ! Thanks! Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
