linux-kernel - Re: [PATCH V7 1/5] interconnect: core: Add dynamic id allocation support

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: <pu3s3fjkt2663wce2632s25oys56wkhsc22lcc5ydepfc4pbll@n73ouprb25zj>
Date: Sat, 11 Jan 2025 14:57:57 -0600
From: Bjorn Andersson <andersson@...nel.org>
To: Raviteja Laggyshetty <quic_rlaggysh@...cinc.com>
Cc: Georgi Djakov <djakov@...nel.org>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Konrad Dybcio <konradybcio@...nel.org>, Odelu Kukatla <quic_okukatla@...cinc.com>, 
	Mike Tipton <mdptipton@...cinc.com>, Vivek Aknurwar <viveka@...cinc.com>, 
	Sibi Sankar <quic_sibis@...cinc.com>, linux-arm-msm@...r.kernel.org, linux-pm@...r.kernel.org, 
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH V7 1/5] interconnect: core: Add dynamic id allocation
 support

On Sat, Jan 11, 2025 at 04:14:25PM +0000, Raviteja Laggyshetty wrote:
> Current interconnect framework is based on static IDs for creating node
> and registering with framework. This becomes a limitation for topologies
> where there are multiple instances of same interconnect provider. Add
> icc_node_create_alloc_id() API to create icc node with dynamic id, this
> will help to overcome the dependency on static IDs.
> 
> Signed-off-by: Raviteja Laggyshetty <quic_rlaggysh@...cinc.com>
> ---
>  drivers/interconnect/core.c           | 32 +++++++++++++++++++++++++++
>  include/linux/interconnect-provider.h |  6 +++++
>  2 files changed, 38 insertions(+)
> 
> diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c
> index 9d5404a07e8a..0b7093eb51af 100644
> --- a/drivers/interconnect/core.c
> +++ b/drivers/interconnect/core.c
> @@ -858,6 +858,38 @@ struct icc_node *icc_node_create(int id)
>  }
>  EXPORT_SYMBOL_GPL(icc_node_create);
>  
> +/**
> + * icc_node_create_alloc_id() - create node and dynamically allocate id
> + * @start_id: min id to be allocated
> + *
> + * Return: icc_node pointer on success, or ERR_PTR() on error
> + */
> +struct icc_node *icc_node_create_alloc_id(int start_id)

By having clients pass in start_id, you distribute the decision of what
a "good number" is across multiple parts of the system (or you have
clients relying on getting [start_id, start_id + N) back).

Wouldn't it be better to hide that choice in one place (inside the icc
framework)?

Regards,
Bjorn

> +{
> +	struct icc_node *node;
> +	int id;
> +
> +	mutex_lock(&icc_lock);
> +
> +	node = kzalloc(sizeof(*node), GFP_KERNEL);
> +	if (!node)
> +		return ERR_PTR(-ENOMEM);
> +
> +	id = idr_alloc(&icc_idr, node, start_id, 0, GFP_KERNEL);
> +	if (id < 0) {
> +		WARN(1, "%s: couldn't get idr\n", __func__);
> +		kfree(node);
> +		node = ERR_PTR(id);
> +		goto out;
> +	}
> +	node->id = id;
> +out:
> +	mutex_unlock(&icc_lock);
> +
> +	return node;
> +}
> +EXPORT_SYMBOL_GPL(icc_node_create_alloc_id);
> +
>  /**
>   * icc_node_destroy() - destroy a node
>   * @id: node id
> diff --git a/include/linux/interconnect-provider.h b/include/linux/interconnect-provider.h
> index f5aef8784692..4fc7a5884374 100644
> --- a/include/linux/interconnect-provider.h
> +++ b/include/linux/interconnect-provider.h
> @@ -117,6 +117,7 @@ struct icc_node {
>  int icc_std_aggregate(struct icc_node *node, u32 tag, u32 avg_bw,
>  		      u32 peak_bw, u32 *agg_avg, u32 *agg_peak);
>  struct icc_node *icc_node_create(int id);
> +struct icc_node *icc_node_create_alloc_id(int start_id);
>  void icc_node_destroy(int id);
>  int icc_link_create(struct icc_node *node, const int dst_id);
>  void icc_node_add(struct icc_node *node, struct icc_provider *provider);
> @@ -141,6 +142,11 @@ static inline struct icc_node *icc_node_create(int id)
>  	return ERR_PTR(-ENOTSUPP);
>  }
>  
> +static inline struct icc_node *icc_node_create_alloc_id(int start_id)
> +{
> +	return ERR_PTR(-EOPNOTSUPP);
> +}
> +
>  static inline void icc_node_destroy(int id)
>  {
>  }
> -- 
> 2.39.2
>