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Date:   Wed, 4 Jan 2023 16:29:44 -0800
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Subject: Re: [PATCH v10 11/13] x86/resctrl: Add interface to write
 mbm_total_bytes_config
To:     Babu Moger <babu.moger@amd.com>, <corbet@lwn.net>,
        <tglx@linutronix.de>, <mingo@redhat.com>, <bp@alien8.de>
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References: <20221222233127.910538-1-babu.moger@amd.com>
 <20221222233127.910538-12-babu.moger@amd.com>
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From:   Reinette Chatre <reinette.chatre@intel.com>
In-Reply-To: <20221222233127.910538-12-babu.moger@amd.com>
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Hi Babu,

On 12/22/2022 3:31 PM, Babu Moger wrote:

...

> +static ssize_t mbm_total_bytes_config_write(struct kernfs_open_file *of,
> +					    char *buf, size_t nbytes,
> +					    loff_t off)
> +{
> +	struct rdt_resource *r = of->kn->parent->priv;
> +	int ret;
> +
> +	/* Valid input requires a trailing newline */
> +	if (nbytes == 0 || buf[nbytes - 1] != '\n')
> +		return -EINVAL;
> +
> +	cpus_read_lock();

Could you please elaborate why this lock is needed here as
well as in the following patch?

Reinette