Re: [RFC PATCH 4/4] cxl/region: Introduce cxl_memdev_attach_region

[Alejandro Lucero Palau <alucerop@amd.com>]

On 4/14/26 16:41, Alejandro Lucero Palau wrote:

<snip>
>
> Also, if the cxl_mem unbinding happens after the type2 driver has 
> invoked ioremap, the driver will be using something it should not. 
> Won't it? I do not think that is correct and the type2 driver should 
> somehow get a notification for stopping using such a range, some sort 
> of detach function the cxl core can invoke. That is something I 
> unsuccessfully tried to add in the past:
>
>
> https://lore.kernel.org/linux-cxl/20250624141355.269056-19-alejandro.lucero-palau@amd.com/ 
>
>
>

FWIW, in that v17 I add the callback function in here:


https://lore.kernel.org/linux-cxl/20250624141355.269056-21-alejandro.lucero-palau@amd.com/


which gets completed in the last patch for integrating the sfc driver 
cxl pio buffers unwinding.


I think that is necessary. About this patch, I think it should be part 
of Type2 series with changes for adding the ioremap to the protected cxl 
region "attachment". After that the CXL region can be safely used ... 
until the sfc driver explicitly exits or until the callback is invoked 
triggered by cxl_acpi removal or cxl_mem unbinding. The sfc driver will 
safely stop using pio buffers keeping the normal packet sending using DMA.


I'll work on a v26 with these changes.