Re: [PATCH 1/9] alpha: Convert mapping routine to rely on physical address

[Magnus Lindholm <linmag7@xxxxxxxxx>]

On Thu, Sep 18, 2025 at 8:45 PM Leon Romanovsky <leon@xxxxxxxxxx> wrote:
>
> From: Leon Romanovsky <leonro@xxxxxxxxxx>
>
> Alpha doesn't need struct *page and can perform mapping based on
> physical addresses. So convert it to implement new .map_phys callback.


Hi,

SInce this patch affects the Alpha platform I got curious and decided to
try it out. The patch series requires some preparatory patches. Leon
provided me with links to his dmabuf-vfio branch, which had the
patches (and some prerequisite stuff) applied already.

Based on the dmabuf-vfio branch,  I've built a kernel and tested it on
my ES40 Alphaserver, the kernel booted fine but after a while of
moderate filesystem load I started seeing some ext3/4 related error
messages in the system logs. Rebooting with my old kernel into
single user mode, I was able to recover the filesystem using fsck.
Clearly this set of patches breaks things (at least on Alpha).

I haven't yet dug any deeper into the root causes of the file system
corruptions and I've only tested this on Alpha, maybe there has been
more testing done on other platforms targeted by this set
of patches?

Regards

Magnus Lindholm