Re: [PATCH v2 1/1] cxl/test: Update mock dev array before calling platform_device_add()

[Alison Schofield]

On Fri, May 22, 2026 at 07:50:59PM +0800, Li Ming wrote:
> 
> 在 2026/5/21 20:25, Li Ming 写道:
> > 
> > 在 2026/5/21 15:25, Alison Schofield 写道:
> > > On Wed, May 20, 2026 at 08:14:57PM +0800, Li Ming wrote:
> > > > CXL test environment hits the following error sometimes.
> > > > 
> > > >   cxl_mem mem9: endpoint7 failed probe
> > > > 
> > > > All mock memdevs are platform firmware devices added by cxl_test
> > > > module,
> > > > and cxl_test module also provides a platform device driver for them to
> > > > create a memdev device to CXL subsystem. cxl_test module uses
> > > > cxl_rcd/mem_single/mem arrays to store different types of mock memdevs.
> > > > CXL drivers calls registered mock functions for a mock memdev by
> > > > checking if a given memdev is in these arrays.
> > > > 
> > > > When cxl_test module adds these mock memdevs, it always calls
> > > > platform_device_add() before adding them to a suitable mock memdev
> > > > array. However, there is a small window where CXL drivers calls mock
> > > > function for a added memdev before it added to a mock memdev array. In
> > > > above case, cxl endpoint driver considers a added memdev was not a mock
> > > > memdev, then calling devm_cxl_endpoint_decoders_setup() for it rather
> > > > than mock_endpoint_decoders_setup().
> > > > 
> > > > An appropriate solution is that adding a new mock device to a mock
> > > > device array before calling platform_device_add() for it. It can
> > > > guarantee the new mock device is visible to CXL subsystem.
> > > > 
> > > > This patch introduces a new helped called
> > > > cxl_mock_platform_device_add()
> > > > to handle the issue, and uses the function for all mock devices
> > > > addition.
> > > > 
> > > Reviewed-by: Alison Schofield <alison.schofield@xxxxxxxxx>
> > 
> > Hi Alison,
> > 
> > 
> > I missed that you mentioned putting platform_device_alloc() into the
> > helper. I will send out v3 for that.
> > 
> > 
> After taking a look into the implementation, maybe keep current
> implementation would be better.
> 
> This helper is responsible for performing the platform_device_add()
> operation for all mock devices. However, each type of mock device has its
> own specific logic between platform_device_alloc() and
> platform_device_add().
> 
> If I move platform_device_alloc() into this helper,I will also have to
> incorporate all these device-specific implementations.

That makes sense Ming. Thanks for trying it out.

I'll add to my previous tag,

Tested-by: Alison Schofield <alison.schofield@xxxxxxxxx>

> 
> Ming
> 
> > Ming
> > 
snip