linux-kernel - Re: [PATCH v9 5/9] x86/resctrl: Unwind the errors inside rdt_enable

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Message-ID: <2d6eb068-f326-7397-bf0d-d47fea01f199@amd.com>
Date:   Tue, 12 Sep 2023 11:54:40 -0500
From:   "Moger, Babu" <babu.moger@....com>
To:     Reinette Chatre <reinette.chatre@...el.com>, corbet@....net,
        tglx@...utronix.de, mingo@...hat.com, bp@...en8.de
Cc:     fenghua.yu@...el.com, dave.hansen@...ux.intel.com, x86@...nel.org,
        hpa@...or.com, paulmck@...nel.org, akpm@...ux-foundation.org,
        quic_neeraju@...cinc.com, rdunlap@...radead.org,
        damien.lemoal@...nsource.wdc.com, songmuchun@...edance.com,
        peterz@...radead.org, jpoimboe@...nel.org, pbonzini@...hat.com,
        chang.seok.bae@...el.com, pawan.kumar.gupta@...ux.intel.com,
        jmattson@...gle.com, daniel.sneddon@...ux.intel.com,
        sandipan.das@....com, tony.luck@...el.com, james.morse@....com,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
        bagasdotme@...il.com, eranian@...gle.com,
        christophe.leroy@...roup.eu, jarkko@...nel.org,
        adrian.hunter@...el.com, quic_jiles@...cinc.com,
        peternewman@...gle.com
Subject: Re: [PATCH v9 5/9] x86/resctrl: Unwind the errors inside
 rdt_enable_ctx()

Hi Reinette,

On 9/11/23 17:58, Reinette Chatre wrote:
> Hi Babu,
> 
> On 9/7/2023 4:51 PM, Babu Moger wrote:
>> rdt_enable_ctx() enables the features provided during resctrl mount.
>>
>> Additions to rdt_enable_ctx() are required to also modify error paths
>> of rdt_enable_ctx() callers to ensure correct unwinding if errors
>> are encountered after calling rdt_enable_ctx(). This is error prone.
>>
>> Introduce rdt_disable_ctx() to refactor the error unwinding of
>> rdt_enable_ctx() to simplify future additions. This also simplifies
>> cleanup in rdt_kill_sb().
>>
>> Remove cdp_disable_all() as it is not used anymore after the refactor.
>>
>> Suggested-by: Reinette Chatre <reinette.chatre@...el.com>
>> Reviewed-by: Fenghua Yu <fenghua.yu@...el.com>
>> Signed-off-by: Babu Moger <babu.moger@....com>
>> ---
> 
> This is one of the patches that received a change that was not
> mentioned in cover letter nor in a patch specific list of changes.

Yes. My bad.

> 
> Having a list of changes within each patch in this area is
> helpful in reviews.
> 
>>  arch/x86/kernel/cpu/resctrl/rdtgroup.c | 55 ++++++++++++++++----------
>>  1 file changed, 34 insertions(+), 21 deletions(-)
>>
>> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> index 35945b4bf196..34cb512be1de 100644
>> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> @@ -2290,14 +2290,6 @@ int resctrl_arch_set_cdp_enabled(enum resctrl_res_level l, bool enable)
>>  	return 0;
>>  }
>>  
>> -static void cdp_disable_all(void)
>> -{
>> -	if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L3))
>> -		resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L3, false);
>> -	if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L2))
>> -		resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L2, false);
>> -}
>> -
>>  /*
>>   * We don't allow rdtgroup directories to be created anywhere
>>   * except the root directory. Thus when looking for the rdtgroup
>> @@ -2377,19 +2369,44 @@ static int mkdir_mondata_all(struct kernfs_node *parent_kn,
>>  			     struct rdtgroup *prgrp,
>>  			     struct kernfs_node **mon_data_kn);
>>  
>> +static void rdt_disable_ctx(void)
>> +{
>> +	resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L3, false);
>> +
>> +	resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L2, false);
>> +
>> +	set_mba_sc(false);
>> +}
> 
> Could you please remove the empty line following each call?

Sure.

> 
> With the above change you can add:
> 
> Reviewed-by: Reinette Chatre <reinette.chatre@...el.com>
-- 
Thanks
Babu Moger