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Message-ID: <54236122-55d8-fd4a-1791-e6f96a61e3f0@amd.com>
Date: Wed, 30 Aug 2023 11:38:45 -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
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Subject: Re: [PATCH v8 5/8] x86/resctrl: Unwind the errors inside
rdt_enable_ctx()
Hi Reinette,
On 8/29/23 15:10, Reinette Chatre wrote:
> Hi Babu,
>
> On 8/21/2023 4:30 PM, Babu Moger wrote:
>> static int rdt_enable_ctx(struct rdt_fs_context *ctx)
>> {
>> int ret = 0;
>>
>> - if (ctx->enable_cdpl2)
>> + if (ctx->enable_cdpl2) {
>> ret = resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L2, true);
>> + if (ret)
>> + goto out_done;
>> + }
>>
>> - if (!ret && ctx->enable_cdpl3)
>> + if (ctx->enable_cdpl3) {
>> ret = resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L3, true);
>> + if (ret)
>> + goto out_cdpl2;
>> + }
>>
>> - if (!ret && ctx->enable_mba_mbps)
>> + if (ctx->enable_mba_mbps) {
>> ret = set_mba_sc(true);
>> + if (ret)
>> + goto out_cdpl3;
>
> An error may be encountered here without CDP ever enabled or just
> enabled for L2 or L3. I think that the error unwinding should
> take care to not unwind an action that was not done. Considering
> the information available I think checking either ctx->enable_...
> or the checks used in rdt_disable_ctx() would be ok but for consistency
> the resctrl_arch_get_cdp_enabled() checks may be most appropriate.
>
>> + }
>> +
>> + return 0;
>>
>> +out_cdpl3:
>
> So here I think there should be a check.
> if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L3))
>
>> + resctrl_arch_set_cdp_enabled(RDT_RESOURCE_L3, false);
>> +out_cdpl2:
>
> ... and here a check:
> if (resctrl_arch_get_cdp_enabled(RDT_RESOURCE_L2))
I know it does not hurt to add these checks. But, it may be unnecessary
considering cdp_disable() has the check "if (r_hw->cdp_enabled)" already.
Both are same checks. What do you think?
--
Thanks
Babu Moger
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