Re: [RFC type cxl initialization 1/2] cxl: add type2 device basic support

[Dan Williams <dan.j.williams@intel.com>]

Ben Cheatham wrote:
> On 2/20/25 2:00 PM, alejandro.lucero-palau@amd.com wrote:
> > From: Alejandro Lucero <alucerop@amd.com>
> > 
> > Differentiate CXL memory expanders (type 3) from CXL device accelerators
> > (type 2) with a new function for initializing cxl_dev_state and a macro
> > for helping accel drivers to embed cxl_dev_state inside a private
> > struct.
> > 
> > Move structs to include/cxl as the size of the accel driver private
> > struct embedding cxl_dev_state needs to know the size of this struct.
> > 
> > Signed-off-by: Alejandro Lucero <alucerop@amd.com>
[..]
> diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
> index 2c49e33851b2..14d7f93e4584 100644
> --- a/drivers/cxl/core/mbox.c
> +++ b/drivers/cxl/core/mbox.c
> @@ -1484,24 +1484,31 @@ int cxl_mailbox_init(struct cxl_mailbox *cxl_mbox, struct device *host)
>  }
>  EXPORT_SYMBOL_NS_GPL(cxl_mailbox_init, "CXL");
> 
> +static void cxl_memdev_state_destroy(void *cxlmds)
> +{
> +       kfree(cxlmds);
> +}
> +
>  struct cxl_memdev_state *cxl_memdev_state_create(struct device *dev, u64 serial,
>                                                  u16 dvsec)
>  {
>         struct cxl_memdev_state *mds;
>         int rc;
> 
> -       mds = devm_kzalloc(dev, sizeof(*mds), GFP_KERNEL);
> +       mds = cxl_dev_state_create(dev, serial, dvsec,
> +                                  CXL_DEVTYPE_CLASSMEM,
> +                                  struct cxl_memdev_state,
> +                                  cxlds);
>         if (!mds) {
>                 dev_err(dev, "No memory available\n");
>                 return ERR_PTR(-ENOMEM);
>         }
> 
> +       rc = devm_add_action_or_reset(dev, cxl_memdev_state_destroy, mds);
> +       if (rc)
> +               return ERR_PTR(rc);
> +
>         mutex_init(&mds->event.log_lock);
> -       mds->cxlds.dev = dev;
> -       mds->cxlds.reg_map.host = dev;
> -       mds->cxlds.cxl_mbox.host = dev;
> -       mds->cxlds.reg_map.resource = CXL_RESOURCE_NONE;
> -       mds->cxlds.type = CXL_DEVTYPE_CLASSMEM;
> 
> 
> Looking at the above, it occurs to me that it may be good to either:
> 
> a) Have a devm version of cxl_dev_state_create() or,
> b) Have an init macro (in addition) that takes a pointer so that you can use an
> allocator of your choice

The caller can always wrap the result with devm_add_action_or_reset().
No need to force comsumer drivers into an allocation regime.