linux-kernel - Re: [PATCH 11/33] arm_mpam: Add the class and component structures for firmware described ris

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Message-ID: <316b04af-2005-47f0-887d-6e9d4031df5b@nvidia.com>
Date: Wed, 12 Nov 2025 19:23:51 -0800
From: Fenghua Yu <fenghuay@...dia.com>
To: Ben Horgan <ben.horgan@....com>, james.morse@....com
Cc: amitsinght@...vell.com, baisheng.gao@...soc.com,
 baolin.wang@...ux.alibaba.com, bobo.shaobowang@...wei.com,
 carl@...amperecomputing.com, catalin.marinas@....com, dakr@...nel.org,
 dave.martin@....com, david@...hat.com, dfustini@...libre.com,
 gregkh@...uxfoundation.org, gshan@...hat.com, guohanjun@...wei.com,
 jeremy.linton@....com, jonathan.cameron@...wei.com, kobak@...dia.com,
 lcherian@...vell.com, lenb@...nel.org, linux-acpi@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
 lpieralisi@...nel.org, peternewman@...gle.com, quic_jiles@...cinc.com,
 rafael@...nel.org, robh@...nel.org, rohit.mathew@....com,
 scott@...amperecomputing.com, sdonthineni@...dia.com, sudeep.holla@....com,
 tan.shaopeng@...itsu.com, will@...nel.org, xhao@...ux.alibaba.com,
 Shaopeng Tan <tan.shaopeng@...fujitsu.com>
Subject: Re: [PATCH 11/33] arm_mpam: Add the class and component structures
 for firmware described ris

Hi, Ben and James,

On 11/7/25 04:34, Ben Horgan wrote:
> From: James Morse <james.morse@....com>

[SNIP]

> +static int mpam_ris_create_locked(struct mpam_msc *msc, u8 ris_idx,
> +				  enum mpam_class_types type, u8 class_id,
> +				  int component_id)
> +{
> +	int err;
> +	struct mpam_vmsc *vmsc;
> +	struct mpam_msc_ris *ris;
> +	struct mpam_class *class;
> +	struct mpam_component *comp;
> +	struct platform_device *pdev = msc->pdev;
> +
> +	lockdep_assert_held(&mpam_list_lock);
> +
> +	if (ris_idx > MPAM_MSC_MAX_NUM_RIS)
> +		return -EINVAL;
> +
> +	if (test_and_set_bit(ris_idx, &msc->ris_idxs))
> +		return -EBUSY;
> +
> +	ris = devm_kzalloc(&msc->pdev->dev, sizeof(*ris), GFP_KERNEL);
> +	if (!ris)
> +		return -ENOMEM;

The ris_idx bit in msc->ris_idxs is not cleared on error paths in this 
function. The bit cannot be set again.

Not sure if this is a real problem in any case. Clearing the bit on 
error paths may be clean code.

[SNIP]

Thanks.

-Fenghua