Re: [PATCH 3/5] cxl/memdev: Pin parents for entire memdev lifetime

[Dave Jiang <dave.jiang@intel.com>]

On 5/19/26 2:01 PM, Dan Williams wrote:
> In order to be able to manage the driver that uses a memdev attach
> mechanism the parent needs to stick around for the
> device_release_driver(cxlmd->dev.parent) event.
> 
> Fixes: 29317f8dc6ed ("cxl/mem: Introduce cxl_memdev_attach for CXL-dependent operation")
> Signed-off-by: Dan Williams <djbw@kernel.org>

Reviewed-by: Dave Jiang <dave.jiang@intel.com>

Maybe a comment above get_device() to make note of why we are taking the reference.

> ---
>  drivers/cxl/core/memdev.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
> index 80e65690eb77..91c99eeea92c 100644
> --- a/drivers/cxl/core/memdev.c
> +++ b/drivers/cxl/core/memdev.c
> @@ -25,9 +25,11 @@ static DEFINE_IDA(cxl_memdev_ida);
>  static void cxl_memdev_release(struct device *dev)
>  {
>  	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
> +	struct device *parent = dev->parent;
>  
>  	ida_free(&cxl_memdev_ida, cxlmd->id);
>  	kfree(cxlmd);
> +	put_device(parent);
>  }
>  
>  static char *cxl_memdev_devnode(const struct device *dev, umode_t *mode, kuid_t *uid,
> @@ -707,7 +709,7 @@ static struct cxl_memdev *cxl_memdev_alloc(struct cxl_dev_state *cxlds,
>  	dev = &cxlmd->dev;
>  	device_initialize(dev);
>  	lockdep_set_class(&dev->mutex, &cxl_memdev_key);
> -	dev->parent = cxlds->dev;
> +	dev->parent = get_device(cxlds->dev);
>  	dev->bus = &cxl_bus_type;
>  	dev->devt = MKDEV(cxl_mem_major, cxlmd->id);
>  	dev->type = &cxl_memdev_type;