Re: [PATCH rdma-next 1/2] arm64/io: add memcpy_toio_64

[Niklas Schnelle <schnelle@linux.ibm.com>]

On Thu, 2024-01-18 at 12:21 -0400, Jason Gunthorpe wrote:
> On Thu, Jan 18, 2024 at 04:59:47PM +0100, Niklas Schnelle wrote:
> > On Thu, 2024-01-18 at 10:00 -0400, Jason Gunthorpe wrote:
> > > On Thu, Jan 18, 2024 at 02:46:40PM +0100, Niklas Schnelle wrote:
> > > 
> > > > Yes, we need zpci_memcpy_toio(to, from, count * 8) since our count is
> > > > in bytes like for memcpy_toio().
> > > 
> > > https://github.com/jgunthorpe/linux/commits/mlx5_wc/
> > > 
> > > Jason
> > > 
> > 
> > Thanks, the s390 patches:
> > 
> > 
> > s390: Implement __iowrite32_copy() 
> > s390: Use the correct count for __iowrite64_copy() 
> > s390: Stop using weak symbols for __iowrite64_copy() 
> > 
> > Look good to me. I.e. you may add my.
> > 
> > Acked-by Niklas Schnelle <schnelle@linux.ibm.com>
> 
> Great, thanks. I'll post this once rc1 comes out
> 
> > I did test your patches too and by accident confirmed again that these
> > do need commit 80df7d6af7f6 ("s390/pci: fix max size calculation in
> > zpci_memcpy_toio()") from the s390 feature branch to get the mlx5
> > driver to detect Write-Combining as supported. Note, as far as I know
> > Alexander Gordeev is targeting that one for v6.8-rc2 since we had quite
> > a few changes for v6.8-rc1.
> 
> OK, but we can still run these two things in parallel?
> 
> Jason

Sure, it's not worse without my patch than what we had before and
clearly __iowrite64_copy() has been completely broken for ages without
anyone noticing and is fixed by your patches even without my fix for
the too strict issue in that at least it then copies what it is
supposed to copy even if it does so with 8*8 byte stores.

Thanks,
Niklas