linux-kernel - Re: [PATCH v2 1/2] drivers: base: cacheinfo: Do not populate sysfs for unknown cache types

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Message-ID: <3e842dd3-9b92-c56b-c45a-72d99b37f946@arm.com>
Date:   Fri, 14 Sep 2018 12:14:11 -0500
From:   Jeremy Linton <jeremy.linton@....com>
To:     Jeffrey Hugo <jhugo@...eaurora.org>, sudeep.holla@....com,
        gregkh@...uxfoundation.org, rjw@...ysocki.net,
        linux-acpi@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, vkilari@...eaurora.org
Subject: Re: [PATCH v2 1/2] drivers: base: cacheinfo: Do not populate sysfs
 for unknown cache types

Hi,

On 09/14/2018 11:28 AM, Jeffrey Hugo wrote:
> If a cache has an unknown type because neither the hardware nor the
> firmware told us, an entry in the sysfs tree will be made, but the type
> file will not be present.  lscpu depends on the type file being present
> for every entry, and will error out without printing system information
> if lscpu cannot open the type file.
> 
> Presenting information about a cache without indicating its type is not
> useful, therefore if we hit a cache with an unknown type, stop populating
> sysfs so that userspace has the maximum amount of useful information.
> 
> This addresses the following lscpu error, which prevents any output.
> lscpu: cannot open /sys/devices/system/cpu/cpu0/cache/index3/type: No such
> file or directory
> 
> Suggested-by: Sudeep Holla <sudeep.holla@....com>
> Signed-off-by: Jeffrey Hugo <jhugo@...eaurora.org>
> ---
>   drivers/base/cacheinfo.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
> index 5d5b598..cf78fa6 100644
> --- a/drivers/base/cacheinfo.c
> +++ b/drivers/base/cacheinfo.c
> @@ -615,6 +615,8 @@ static int cache_add_dev(unsigned int cpu)
>   		this_leaf = this_cpu_ci->info_list + i;
>   		if (this_leaf->disable_sysfs)
>   			continue;
> +		if (this_leaf->type == CACHE_TYPE_NOCACHE)
> +			break;
>   		cache_groups = cache_get_attribute_groups(this_leaf);
>   		ci_dev = cpu_device_create(parent, this_leaf, cache_groups,
>   					   "index%1u", i);
> 

Looks fine to me:

Reviewed-by: Jeremy Linton <jeremy.linton@....com>


Thanks,