Re: [PATCH 1/6] cxl/mem: Fix devm_cxl_memdev_edac_release() confusion

[Alejandro Lucero Palau <alucerop@amd.com>]

On 12/4/25 02:21, Dan Williams wrote:
> A device release method is only for undoing allocations on the path to
> preparing the device for device_add(). In contrast, devm allocations are


Should this not be referencing to device_del() instead?


> post device_add(), are acquired during / after ->probe() and are released
> synchronous with ->remove().
>
> So, a "devm" helper in a "release" method is a clear anti-pattern.
>
> Move this devm release action where it belongs, an action created at edac
> object creation time. Otherwise, this leaks resources until
> cxl_memdev_release() time which may be long after these xarray and error
> record caches have gone idle.
>
> Note, this also fixes up the type of @cxlmd->err_rec_array which needlessly
> dropped type-safety.
>
> Fixes: 0b5ccb0de1e2 ("cxl/edac: Support for finding memory operation attributes from the current boot")
> Cc: Dave Jiang <dave.jiang@intel.com>
> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Cc: Shiju Jose <shiju.jose@huawei.com>
> Cc: Alison Schofield <alison.schofield@intel.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
>   drivers/cxl/cxlmem.h      |  5 +--
>   drivers/cxl/core/edac.c   | 64 ++++++++++++++++++++++-----------------
>   drivers/cxl/core/memdev.c |  1 -
>   3 files changed, 38 insertions(+), 32 deletions(-)
>
> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
> index 434031a0c1f7..c12ab4fc9512 100644
> --- a/drivers/cxl/cxlmem.h
> +++ b/drivers/cxl/cxlmem.h
> @@ -63,7 +63,7 @@ struct cxl_memdev {
>   	int depth;
>   	u8 scrub_cycle;
>   	int scrub_region_id;
> -	void *err_rec_array;
> +	struct cxl_mem_err_rec *err_rec_array;
>   };
>   
>   static inline struct cxl_memdev *to_cxl_memdev(struct device *dev)
> @@ -877,7 +877,6 @@ int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd);
>   int devm_cxl_region_edac_register(struct cxl_region *cxlr);
>   int cxl_store_rec_gen_media(struct cxl_memdev *cxlmd, union cxl_event *evt);
>   int cxl_store_rec_dram(struct cxl_memdev *cxlmd, union cxl_event *evt);
> -void devm_cxl_memdev_edac_release(struct cxl_memdev *cxlmd);
>   #else
>   static inline int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd)
>   { return 0; }
> @@ -889,8 +888,6 @@ static inline int cxl_store_rec_gen_media(struct cxl_memdev *cxlmd,
>   static inline int cxl_store_rec_dram(struct cxl_memdev *cxlmd,
>   				     union cxl_event *evt)
>   { return 0; }
> -static inline void devm_cxl_memdev_edac_release(struct cxl_memdev *cxlmd)
> -{ return; }
>   #endif
>   
>   #ifdef CONFIG_CXL_SUSPEND
> diff --git a/drivers/cxl/core/edac.c b/drivers/cxl/core/edac.c
> index 79994ca9bc9f..81160260e26b 100644
> --- a/drivers/cxl/core/edac.c
> +++ b/drivers/cxl/core/edac.c
> @@ -1988,6 +1988,40 @@ static int cxl_memdev_soft_ppr_init(struct cxl_memdev *cxlmd,
>   	return 0;
>   }
>   
> +static void err_rec_free(void *_cxlmd)
> +{
> +	struct cxl_memdev *cxlmd = _cxlmd;
> +	struct cxl_mem_err_rec *array_rec = cxlmd->err_rec_array;
> +	struct cxl_event_gen_media *rec_gen_media;
> +	struct cxl_event_dram *rec_dram;
> +	unsigned long index;
> +
> +	cxlmd->err_rec_array = NULL;
> +	xa_for_each(&array_rec->rec_dram, index, rec_dram)
> +		kfree(rec_dram);
> +	xa_destroy(&array_rec->rec_dram);
> +
> +	xa_for_each(&array_rec->rec_gen_media, index, rec_gen_media)
> +		kfree(rec_gen_media);
> +	xa_destroy(&array_rec->rec_gen_media);
> +	kfree(array_rec);
> +}
> +
> +static int devm_cxl_memdev_setup_err_rec(struct cxl_memdev *cxlmd)
> +{
> +	struct cxl_mem_err_rec *array_rec =
> +		kzalloc(sizeof(*array_rec), GFP_KERNEL);
> +
> +	if (!array_rec)
> +		return -ENOMEM;
> +
> +	xa_init(&array_rec->rec_gen_media);
> +	xa_init(&array_rec->rec_dram);
> +	cxlmd->err_rec_array = array_rec;
> +
> +	return devm_add_action_or_reset(&cxlmd->dev, err_rec_free, cxlmd);
> +}
> +
>   int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd)
>   {
>   	struct edac_dev_feature ras_features[CXL_NR_EDAC_DEV_FEATURES];
> @@ -2038,15 +2072,9 @@ int devm_cxl_memdev_edac_register(struct cxl_memdev *cxlmd)
>   		}
>   
>   		if (repair_inst) {
> -			struct cxl_mem_err_rec *array_rec =
> -				devm_kzalloc(&cxlmd->dev, sizeof(*array_rec),
> -					     GFP_KERNEL);
> -			if (!array_rec)
> -				return -ENOMEM;
> -
> -			xa_init(&array_rec->rec_gen_media);
> -			xa_init(&array_rec->rec_dram);
> -			cxlmd->err_rec_array = array_rec;
> +			rc = devm_cxl_memdev_setup_err_rec(cxlmd);
> +			if (rc)
> +				return rc;
>   		}
>   	}
>   
> @@ -2088,22 +2116,4 @@ int devm_cxl_region_edac_register(struct cxl_region *cxlr)
>   }
>   EXPORT_SYMBOL_NS_GPL(devm_cxl_region_edac_register, "CXL");
>   
> -void devm_cxl_memdev_edac_release(struct cxl_memdev *cxlmd)
> -{
> -	struct cxl_mem_err_rec *array_rec = cxlmd->err_rec_array;
> -	struct cxl_event_gen_media *rec_gen_media;
> -	struct cxl_event_dram *rec_dram;
> -	unsigned long index;
> -
> -	if (!IS_ENABLED(CONFIG_CXL_EDAC_MEM_REPAIR) || !array_rec)
> -		return;
> -
> -	xa_for_each(&array_rec->rec_dram, index, rec_dram)
> -		kfree(rec_dram);
> -	xa_destroy(&array_rec->rec_dram);
>   
> -	xa_for_each(&array_rec->rec_gen_media, index, rec_gen_media)
> -		kfree(rec_gen_media);
> -	xa_destroy(&array_rec->rec_gen_media);
> -}
> -EXPORT_SYMBOL_NS_GPL(devm_cxl_memdev_edac_release, "CXL");
> diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
> index e370d733e440..4dff7f44d908 100644
> --- a/drivers/cxl/core/memdev.c
> +++ b/drivers/cxl/core/memdev.c
> @@ -27,7 +27,6 @@ static void cxl_memdev_release(struct device *dev)
>   	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
>   
>   	ida_free(&cxl_memdev_ida, cxlmd->id);
> -	devm_cxl_memdev_edac_release(cxlmd);
>   	kfree(cxlmd);
>   }
>