linux-kernel - Re: [PATCH 1/8] cxl: Add helper function to retrieve a feature entry

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Z8tGz33l9vDzuJLy@aschofie-mobl2.lan>
Date: Fri, 7 Mar 2025 11:19:43 -0800
From: Alison Schofield <alison.schofield@...el.com>
To: shiju.jose@...wei.com
Cc: linux-cxl@...r.kernel.org, dan.j.williams@...el.com, dave@...olabs.net,
	jonathan.cameron@...wei.com, dave.jiang@...el.com,
	vishal.l.verma@...el.com, ira.weiny@...el.com, david@...hat.com,
	Vilas.Sridharan@....com, linux-edac@...r.kernel.org,
	linux-acpi@...r.kernel.org, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org, bp@...en8.de, tony.luck@...el.com,
	rafael@...nel.org, lenb@...nel.org, mchehab@...nel.org,
	leo.duran@....com, Yazen.Ghannam@....com, rientjes@...gle.com,
	jiaqiyan@...gle.com, Jon.Grimm@....com, dave.hansen@...ux.intel.com,
	naoya.horiguchi@....com, james.morse@....com, jthoughton@...gle.com,
	somasundaram.a@....com, erdemaktas@...gle.com, pgonda@...gle.com,
	duenwen@...gle.com, gthelen@...gle.com,
	wschwartz@...erecomputing.com, dferguson@...erecomputing.com,
	wbs@...amperecomputing.com, nifan.cxl@...il.com,
	tanxiaofei@...wei.com, prime.zeng@...ilicon.com,
	roberto.sassu@...wei.com, kangkang.shen@...urewei.com,
	wanghuiqiang@...wei.com, linuxarm@...wei.com
Subject: Re: [PATCH 1/8] cxl: Add helper function to retrieve a feature entry

On Thu, Feb 27, 2025 at 10:38:08PM +0000, shiju.jose@...wei.com wrote:
> From: Shiju Jose <shiju.jose@...wei.com>
> 
> Add helper function to retrieve a feature entry from the supported
> features list, if supported.
> 
> Signed-off-by: Shiju Jose <shiju.jose@...wei.com>
> ---
>  drivers/cxl/core/core.h     |  2 ++
>  drivers/cxl/core/features.c | 20 ++++++++++++++++++++
>  2 files changed, 22 insertions(+)
> 
> diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
> index 3d3b00835446..6c83f6f18122 100644
> --- a/drivers/cxl/core/core.h
> +++ b/drivers/cxl/core/core.h
> @@ -120,6 +120,8 @@ int cxl_port_get_switch_dport_bandwidth(struct cxl_port *port,
>  int cxl_gpf_port_setup(struct device *dport_dev, struct cxl_port *port);
>  
>  #ifdef CONFIG_CXL_FEATURES
> +struct cxl_feat_entry *cxl_get_feature_entry(struct cxl_dev_state *cxlds,
> +					     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,
> diff --git a/drivers/cxl/core/features.c b/drivers/cxl/core/features.c
> index 048ba4fc3538..c822fb4a8c33 100644
> --- a/drivers/cxl/core/features.c
> +++ b/drivers/cxl/core/features.c
> @@ -203,6 +203,26 @@ int devm_cxl_setup_features(struct cxl_dev_state *cxlds)
>  }
>  EXPORT_SYMBOL_NS_GPL(devm_cxl_setup_features, "CXL");
>  
> +struct cxl_feat_entry *cxl_get_feature_entry(struct cxl_dev_state *cxlds,
> +					     const uuid_t *feat_uuid)
> +{
> +	struct cxl_features_state *cxlfs = to_cxlfs(cxlds);
> +	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->ent;

Do we need some NULL checking here on cxlfs, entries


> +	for (count = 0; count < cxlfs->entries->num_features; count++, feat_entry++) {

Was num_features previously validated? 

> +		if (uuid_equal(&feat_entry->uuid, feat_uuid))
> +			return feat_entry;
> +	}
> +
> +	return ERR_PTR(-ENOENT);

Why not just return NULL?


> +}
> +
>  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,
> -- 
> 2.43.0
>