Re: [PATCH 3/9] cxl/region: Limit visibility of cxl_region_contains_resource()

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

On 3/26/26 10:28 PM, Dan Williams wrote:
> The dax_hmem dependency on cxl_region_contains_resource() is a one-off
> special case. It is not suitable for other use cases.
> 
> Move the definition to the other CONFIG_CXL_REGION guarded definitions in
> drivers/cxl/cxl.h and include that by a relative path include. This matches
> what drivers/dax/cxl.c does for its limited private usage of CXL core
> symbols.
> 
> Reduce the symbol export visibility from global to just dax_hmem, to
> further clarify its applicability.
> 
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>

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

> ---
>  drivers/cxl/cxl.h         |  5 +++++
>  include/cxl/cxl.h         | 15 ---------------
>  drivers/cxl/core/region.c |  3 +--
>  drivers/dax/hmem/hmem.c   |  2 +-
>  4 files changed, 7 insertions(+), 18 deletions(-)
>  delete mode 100644 include/cxl/cxl.h
> 
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index 30a31968f266..84ad04a02bde 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -941,6 +941,7 @@ struct cxl_pmem_region *to_cxl_pmem_region(struct device *dev);
>  int cxl_add_to_region(struct cxl_endpoint_decoder *cxled);
>  struct cxl_dax_region *to_cxl_dax_region(struct device *dev);
>  u64 cxl_port_get_spa_cache_alias(struct cxl_port *endpoint, u64 spa);
> +bool cxl_region_contains_resource(struct resource *res);
>  #else
>  static inline bool is_cxl_pmem_region(struct device *dev)
>  {
> @@ -963,6 +964,10 @@ static inline u64 cxl_port_get_spa_cache_alias(struct cxl_port *endpoint,
>  {
>  	return 0;
>  }
> +static inline bool cxl_region_contains_resource(struct resource *res)
> +{
> +	return false;
> +}
>  #endif
>  
>  void cxl_endpoint_parse_cdat(struct cxl_port *port);
> diff --git a/include/cxl/cxl.h b/include/cxl/cxl.h
> deleted file mode 100644
> index b12d3d0f6658..000000000000
> --- a/include/cxl/cxl.h
> +++ /dev/null
> @@ -1,15 +0,0 @@
> -/* SPDX-License-Identifier: GPL-2.0-only */
> -/* Copyright (c) 2026 Advanced Micro Devices, Inc. */
> -#ifndef _CXL_H_
> -#define _CXL_H_
> -
> -#ifdef CONFIG_CXL_REGION
> -bool cxl_region_contains_resource(struct resource *res);
> -#else
> -static inline bool cxl_region_contains_resource(struct resource *res)
> -{
> -	return false;
> -}
> -#endif
> -
> -#endif /* _CXL_H_ */
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index b72556c1458b..12a9572f34d5 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -12,7 +12,6 @@
>  #include <linux/idr.h>
>  #include <linux/memory-tiers.h>
>  #include <linux/string_choices.h>
> -#include <cxl/cxl.h>
>  #include <cxlmem.h>
>  #include <cxl.h>
>  #include "core.h"
> @@ -4253,7 +4252,7 @@ bool cxl_region_contains_resource(struct resource *res)
>  	return bus_for_each_dev(&cxl_bus_type, NULL, res,
>  				region_contains_resource) != 0;
>  }
> -EXPORT_SYMBOL_GPL(cxl_region_contains_resource);
> +EXPORT_SYMBOL_FOR_MODULES(cxl_region_contains_resource, "dax_hmem");
>  
>  static int cxl_region_can_probe(struct cxl_region *cxlr)
>  {
> diff --git a/drivers/dax/hmem/hmem.c b/drivers/dax/hmem/hmem.c
> index 9ceda6b5cadf..0051e553c33f 100644
> --- a/drivers/dax/hmem/hmem.c
> +++ b/drivers/dax/hmem/hmem.c
> @@ -3,7 +3,7 @@
>  #include <linux/memregion.h>
>  #include <linux/module.h>
>  #include <linux/dax.h>
> -#include <cxl/cxl.h>
> +#include "../../cxl/cxl.h"
>  #include "../bus.h"
>  
>  static bool region_idle;