linux-kernel - Re: [PATCH v3 5/5] perf: arm_cspmu: drop redundant acpi_dev_uid_to

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Message-ID: <ZXQp18e9IR5w41wW@black.fi.intel.com>
Date:   Sat, 9 Dec 2023 10:48:23 +0200
From:   Raag Jadav <raag.jadav@...el.com>
To:     mika.westerberg@...ux.intel.com, andriy.shevchenko@...ux.intel.com,
        rafael@...nel.org, lenb@...nel.org, robert.moore@...el.com,
        ardb@...nel.org, will@...nel.org, mark.rutland@....com
Cc:     linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org,
        acpica-devel@...ts.linuxfoundation.org, linux-efi@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        mallikarjunappa.sangannavar@...el.com, bala.senthil@...el.com
Subject: Re: [PATCH v3 5/5] perf: arm_cspmu: drop redundant
 acpi_dev_uid_to_integer()

On Thu, Nov 23, 2023 at 03:36:17PM +0530, Raag Jadav wrote:
> Now that we have _UID matching support for integer types, we can use
> acpi_dev_hid_uid_match() for it.
> 
> Signed-off-by: Raag Jadav <raag.jadav@...el.com>
> Acked-by: Will Deacon <will@...nel.org>
> ---
>  drivers/perf/arm_cspmu/arm_cspmu.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/perf/arm_cspmu/arm_cspmu.c b/drivers/perf/arm_cspmu/arm_cspmu.c
> index 2cc35dded007..50b89b989ce7 100644
> --- a/drivers/perf/arm_cspmu/arm_cspmu.c
> +++ b/drivers/perf/arm_cspmu/arm_cspmu.c
> @@ -1108,7 +1108,6 @@ static int arm_cspmu_request_irq(struct arm_cspmu *cspmu)
>  
>  static inline int arm_cspmu_find_cpu_container(int cpu, u32 container_uid)
>  {
> -	u64 acpi_uid;
>  	struct device *cpu_dev;
>  	struct acpi_device *acpi_dev;
>  
> @@ -1118,8 +1117,7 @@ static inline int arm_cspmu_find_cpu_container(int cpu, u32 container_uid)
>  
>  	acpi_dev = ACPI_COMPANION(cpu_dev);
>  	while (acpi_dev) {
> -		if (acpi_dev_hid_uid_match(acpi_dev, ACPI_PROCESSOR_CONTAINER_HID, NULL) &&
> -		    !acpi_dev_uid_to_integer(acpi_dev, &acpi_uid) && acpi_uid == container_uid)
> +		if (acpi_dev_hid_uid_match(acpi_dev, ACPI_PROCESSOR_CONTAINER_HID, container_uid))
>  			return 0;

On second thought, I just realized that this can cause false positive
in case container_uid is integer 0.

I'm not aware if that's a valid value to match against in APMT.
If it is, it's better to drop patches 2 and 5 for now.

Raag