Re: [PATCH v19 07/15] cxl: Add helper function to retrieve a feature entry

Dave Jiang
2025-02-11T02:40:12Z

On 2/7/25 7:44 AM, shiju.jose@huawei.com wrote:
> From: Shiju Jose <shiju.jose@huawei.com>
>
> Add helper function to retrieve a feature entry from the supported
> features list, if supported.
>
> Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
> ---
> drivers/cxl/core/features.c | 21 +++++++++++++++++++++
> include/cxl/features.h | 2 ++
> 2 files changed, 23 insertions(+)
>
> diff --git a/drivers/cxl/core/features.c b/drivers/cxl/core/features.c
> index 5f64185a5c7a..bf175e69cda1 100644
> --- a/drivers/cxl/core/features.c
> +++ b/drivers/cxl/core/features.c
> @@ -43,6 +43,27 @@ bool is_cxl_feature_exclusive(struct cxl_feat_entry *entry)
> }
> EXPORT_SYMBOL_NS_GPL(is_cxl_feature_exclusive, "CXL");
>
> +struct cxl_feat_entry *cxl_get_feature_entry(struct cxl_memdev *cxlmd,
> + const uuid_t *feat_uuid)
> +{
> + struct cxl_features_state *cxlfs = cxlmd->cxlfs;
> + struct cxl_feat_entry *feat_entry;
> + int count;
> +
> + /*
> + * Retrieve the feature entry from the supported features list,
> + * if the feature is supported.
> + */
> + feat_entry = cxlfs->entries;
> + for (count = 0; count < cxlfs->num_features; count++, feat_entry++) {
> + if (uuid_equal(&feat_entry->uuid, feat_uuid))
> + return feat_entry;
> + }
> +
> + return ERR_PTR(-ENOENT);
> +}
> +EXPORT_SYMBOL_NS_GPL(cxl_get_feature_entry, "CXL");

You probably don't need this if the memfeature code are in CXL core.

DJ

> +
> size_t cxl_get_feature(struct cxl_mailbox *cxl_mbox, const uuid_t *feat_uuid,
> enum cxl_get_feat_selection selection,
> void *feat_out, size_t feat_out_size, u16 offset,
> diff --git a/include/cxl/features.h b/include/cxl/features.h
> index e52d0573f504..563d966beee5 100644
> --- a/include/cxl/features.h
> +++ b/include/cxl/features.h
> @@ -68,6 +68,8 @@ struct cxl_features_state {
> };
>
> struct cxl_mailbox;
> +struct cxl_feat_entry *cxl_get_feature_entry(struct cxl_memdev *cxlmd,
> + const uuid_t *feat_uuid);
> size_t cxl_get_feature(struct cxl_mailbox *cxl_mbox, const uuid_t *feat_uuid,
> enum cxl_get_feat_selection selection,
> void *feat_out, size_t feat_out_size, u16 offset,