Re: [PATCHv4] cxl: avoid driver data for obtaining cxl_dev_state reference

[Alison Schofield <alison.schofield@intel.com>]

On Tue, Dec 03, 2024 at 04:21:12PM +0000, alucerop@amd.com wrote:
> From: Alejandro Lucero <alucerop@amd.com>
> 
> CXL Type3 pci driver uses struct device driver_data for keeping
> cxl_dev_state reference. Type1/2 drivers are not only about CXL so this
> field should not be used when code requires cxl_dev_state to work with
> and such a code used for Type2 support.
> 
> Change cxl_dvsec_rr_decode for passing cxl_dev_state as a parameter.
> 
> Seize the change for removing the unused cxl_port param.
> 

Dave,

Jonathan previously offered Reviewed-by tag so this looks good to
apply. I've added another review tag and also massaged the 
changelog for your consideration.

cxl/pci: Add Type 1/2 support to cxl_dvsec_rr_decode()

In cxl_dvsec_rr_decode() the pci driver expects to retrieve a cxlds,
struct cxl_dev_state, from the driver_data field of struct device.
While that works for Type 3, drivers for Type 1/2 devices may not
put a cxlds in the driver_data field.

In preparation for supporting Type 1/2 devices, replace parameter
'struct device' with 'struct cxl_dev_state' in cxl_dvsec_rr_decode().

Remove the unused parameter 'cxl_port' in cxl_dvsec_rr_decode().

[as: massaged commit msg and log]
Reviewed-by: Alison Schofield <alison.schofield@intel.com>


> Signed-off-by: Alejandro Lucero <alucerop@amd.com>
> ---
>  drivers/cxl/core/pci.c        | 6 +++---
>  drivers/cxl/cxl.h             | 3 ++-
>  drivers/cxl/port.c            | 2 +-
>  tools/testing/cxl/test/mock.c | 6 +++---
>  4 files changed, 9 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
> index 5b46bc46aaa9..420e4be85a1f 100644
> --- a/drivers/cxl/core/pci.c
> +++ b/drivers/cxl/core/pci.c
> @@ -291,11 +291,11 @@ static int devm_cxl_enable_hdm(struct device *host, struct cxl_hdm *cxlhdm)
>  	return devm_add_action_or_reset(host, disable_hdm, cxlhdm);
>  }
>  
> -int cxl_dvsec_rr_decode(struct device *dev, struct cxl_port *port,
> +int cxl_dvsec_rr_decode(struct cxl_dev_state *cxlds,
>  			struct cxl_endpoint_dvsec_info *info)
>  {
> -	struct pci_dev *pdev = to_pci_dev(dev);
> -	struct cxl_dev_state *cxlds = pci_get_drvdata(pdev);
> +	struct pci_dev *pdev = to_pci_dev(cxlds->dev);
> +	struct device *dev = cxlds->dev;
>  	int hdm_count, rc, i, ranges = 0;
>  	int d = cxlds->cxl_dvsec;
>  	u16 cap, ctrl;
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index f6015f24ad38..fdac3ddb8635 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -821,7 +821,8 @@ struct cxl_hdm *devm_cxl_setup_hdm(struct cxl_port *port,
>  int devm_cxl_enumerate_decoders(struct cxl_hdm *cxlhdm,
>  				struct cxl_endpoint_dvsec_info *info);
>  int devm_cxl_add_passthrough_decoder(struct cxl_port *port);
> -int cxl_dvsec_rr_decode(struct device *dev, struct cxl_port *port,
> +struct cxl_dev_state;
> +int cxl_dvsec_rr_decode(struct cxl_dev_state *cxlds,
>  			struct cxl_endpoint_dvsec_info *info);
>  
>  bool is_cxl_region(struct device *dev);
> diff --git a/drivers/cxl/port.c b/drivers/cxl/port.c
> index 24041cf85cfb..66e18fe55826 100644
> --- a/drivers/cxl/port.c
> +++ b/drivers/cxl/port.c
> @@ -98,7 +98,7 @@ static int cxl_endpoint_port_probe(struct cxl_port *port)
>  	struct cxl_port *root;
>  	int rc;
>  
> -	rc = cxl_dvsec_rr_decode(cxlds->dev, port, &info);
> +	rc = cxl_dvsec_rr_decode(cxlds, &info);
>  	if (rc < 0)
>  		return rc;
>  
> diff --git a/tools/testing/cxl/test/mock.c b/tools/testing/cxl/test/mock.c
> index f4ce96cc11d4..4f82716cfc16 100644
> --- a/tools/testing/cxl/test/mock.c
> +++ b/tools/testing/cxl/test/mock.c
> @@ -228,16 +228,16 @@ int __wrap_cxl_hdm_decode_init(struct cxl_dev_state *cxlds,
>  }
>  EXPORT_SYMBOL_NS_GPL(__wrap_cxl_hdm_decode_init, CXL);
>  
> -int __wrap_cxl_dvsec_rr_decode(struct device *dev, struct cxl_port *port,
> +int __wrap_cxl_dvsec_rr_decode(struct cxl_dev_state *cxlds,
>  			       struct cxl_endpoint_dvsec_info *info)
>  {
>  	int rc = 0, index;
>  	struct cxl_mock_ops *ops = get_cxl_mock_ops(&index);
>  
> -	if (ops && ops->is_mock_dev(dev))
> +	if (ops && ops->is_mock_dev(cxlds->dev))
>  		rc = 0;
>  	else
> -		rc = cxl_dvsec_rr_decode(dev, port, info);
> +		rc = cxl_dvsec_rr_decode(cxlds, info);
>  	put_cxl_mock_ops(index);
>  
>  	return rc;
> -- 
> 2.17.1
> 
>