On Tue, Apr 8, 2014 at 4:22 AM, Arnd Bergmann arnd@arndb.de wrote:
On Tuesday 08 April 2014 10:50:39 Liviu Dudau wrote:
On Mon, Apr 07, 2014 at 06:58:24PM +0100, Bjorn Helgaas wrote:
On Mon, Apr 7, 2014 at 5:36 AM, Arnd Bergmann arnd@arndb.de wrote:
I think migrating other architectures to use the same code should be a separate effort from adding a generic implementation that can be used by arm64. It's probably a good idea to have patches to convert arm32 and/or microblaze.
Let me reiterate that I am 100% in favor of replacing arch-specific code with more generic implementations.
However, I am not 100% in favor of doing it as separate efforts (although maybe I could be convinced). The reasons I hesitate are that (1) if only one architecture uses a new "generic" implementation, we really don't know whether it is generic enough, (2) until I see the patches to convert other architectures, I have to assume that I'm the one who will write them, and (3) as soon as we add the code to drivers/pci, it becomes partly my headache to maintain it, even if only one arch benefits from it.
Fair enough.
My approach to the asm-generic infrastruction has mostly been to ensure that whoever adds a new architecture has to make things easier for the next person.
That's a good rule. But if we add a generic implementation used only by one architecture, the overall complexity has increased (we added new unshared code), so the next person has to look at N+1 existing implementations. If we even convert one existing arch, that seems like an improvement: we have N implementations with one being used by at least two arches.
Bjorn