On Wed, Jun 07, 2023 at 05:57:39PM +0200, Thierry Reding wrote: > > No, on the contrary, now it's clear you can either have void __iomem * > > and struct gen_pool * or void *virt but not both. > > No, it's not clear. You can have one part of your driver write the > sram.virt field and another read dram.virt and they'll end up pointing > at the same memory location but with different meaning. That's why you > need to introduce the enumeration in order to specify which one of the > two you want to pick. > > And that's exactly where you start introducing the potential for > inconsistency: now you need to be extra careful that the enumeration and > the unions are set correctly. You effectively have two sources of truth > and they don't necessarily match. You can also end up (at least > theoretically) with the invalid value, so you need an extra check for > that too. > > You can avoid all of those inconsistencies if you reduce this to one > source of truth, namely the pointers that you're going to use. > There are 4 possible states for these pointers: both NULL both non-NULL sram pointer NULL, dram pointer non-NULL dram pointer NULL, sram pointer non-NULL So how is this one source of truth? Peter.
