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Message-ID: <2010f8dc-7cc6-4a42-a181-37e65fffd22f@intel.com>
Date: Thu, 4 Dec 2025 09:48:13 -0700
From: Dave Jiang <dave.jiang@...el.com>
To: Dan Williams <dan.j.williams@...el.com>
Cc: linux-cxl@...r.kernel.org, linux-kernel@...r.kernel.org,
Smita.KoralahalliChannabasappa@....com, alison.schofield@...el.com,
terry.bowman@....com, alejandro.lucero-palau@....com,
linux-pci@...r.kernel.org, Jonathan.Cameron@...wei.com,
Shiju Jose <shiju.jose@...wei.com>
Subject: Re: [PATCH 1/6] cxl/mem: Fix devm_cxl_memdev_edac_release() confusion
On 12/3/25 7:21 PM, 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
> 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@...el.com>
> Cc: Jonathan Cameron <Jonathan.Cameron@...wei.com>
> Cc: Shiju Jose <shiju.jose@...wei.com>
> Cc: Alison Schofield <alison.schofield@...el.com>
> Signed-off-by: Dan Williams <dan.j.williams@...el.com>
Reviewed-by: Dave Jiang <dave.jiang@...el.com>
This can go into fixes right? Does not look like a dependency for the rest of the series.
> ---
> 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);
> }
>
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