Re: [PATCH v6 07/10] arm_mpam: prepare mon_sel locking for MPAM-Fb

Andre Przywara <[email protected]> Fri, 31 Jul 2026 12:48:28 +0200
Newsgroups org.kernel.vger.linux-acpi,org.infradead.lists.linux-arm-kernel,org.kernel.vger.linux-kernel
Message-ID <[email protected]>
Hi Lee,

On 7/30/26 23:46, Lee Trager wrote:
> On 7/30/26 8:25 AM, Andre Przywara wrote:
> 
>> diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/ 
>> mpam_devices.c
>> index 38450c55e45e..d175d1d50030 100644
>> --- a/drivers/resctrl/mpam_devices.c
>> +++ b/drivers/resctrl/mpam_devices.c
>> @@ -2230,7 +2230,10 @@ static struct mpam_msc 
>> *do_mpam_msc_drv_probe(struct platform_device *pdev)
>>       if (err)
>>           return ERR_PTR(err);
>> -    mpam_mon_sel_lock_init(msc);
>> +    err = mpam_mon_sel_lock_init(dev, msc);
>> +    if (err)
>> +        return ERR_PTR(err);
>> +
>>       msc->id = pdev->id;
>>       msc->pdev = pdev;
>>       INIT_LIST_HEAD_RCU(&msc->all_msc_list);
>>
> msc->iface is set below, it needs to be set before calling 
> mpam_mon_sel_lock_init() so PCC devices initalize mon_sel_mtex, while 
> MMIO initialize the spinlock.

Ouch, that's a good one. This worked before, because we initialised 
both, but indeed now breaks.

Thanks for noticing, just moved the initialisation down now.

Cheers,
Andre