linux-kernel - Re: [PATCH v5 08/34] ACPI: Define acpi_put_table cleanup handler and acpi_get_table

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Message-ID: <CAJZ5v0hAPoE96C7=ynR=Ex4huPP3b896sBRNdBiLe=3Q9vKwHQ@mail.gmail.com>
Date: Mon, 17 Nov 2025 20:46:52 +0100
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Ben Horgan <ben.horgan@....com>
Cc: james.morse@....com, amitsinght@...vell.com, baisheng.gao@...soc.com, 
	baolin.wang@...ux.alibaba.com, bobo.shaobowang@...wei.com, 
	carl@...amperecomputing.com, catalin.marinas@....com, dakr@...nel.org, 
	dave.martin@....com, david@...hat.com, dfustini@...libre.com, 
	fenghuay@...dia.com, gregkh@...uxfoundation.org, gshan@...hat.com, 
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	kobak@...dia.com, lcherian@...vell.com, lenb@...nel.org, 
	linux-acpi@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	linux-kernel@...r.kernel.org, lpieralisi@...nel.org, peternewman@...gle.com, 
	quic_jiles@...cinc.com, rafael@...nel.org, robh@...nel.org, 
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	sudeep.holla@....com, tan.shaopeng@...itsu.com, will@...nel.org, 
	xhao@...ux.alibaba.com, Shaopeng Tan <tan.shaopeng@...fujitsu.com>, 
	Zeng Heng <zengheng4@...wei.com>
Subject: Re: [PATCH v5 08/34] ACPI: Define acpi_put_table cleanup handler and
 acpi_get_table_ret() helper

On Mon, Nov 17, 2025 at 6:01 PM Ben Horgan <ben.horgan@....com> wrote:
>
> Define a cleanup helper for use with __free to release the acpi table when
> the pointer goes out of scope. Also, introduce the helper
> acpi_get_table_ret() to simplify a commonly used pattern involving
> acpi_get_table().
>
> These are first used in a subsequent commit.
>
> Reviewed-by: Gavin Shan <gshan@...hat.com>
> Reviewed-by: Jonathan Cameron <jonathan.cameron@...wei.com>
> Reviewed-by: Shaopeng Tan <tan.shaopeng@...fujitsu.com>
> Reviewed-by: Fenghua Yu <fenghuay@...dia.com>
> Tested-by: Fenghua Yu <fenghuay@...dia.com>
> Tested-by: Carl Worth <carl@...amperecomputing.com>
> Tested-by: Gavin Shan <gshan@...hat.com>
> Tested-by: Zeng Heng <zengheng4@...wei.com>
> Tested-by: Shaopeng Tan <tan.shaopeng@...fujitsu.com>
> Signed-off-by: Ben Horgan <ben.horgan@....com>
> ---
>  include/linux/acpi.h | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
>
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index a9dbacabdf89..1124b7dc79fd 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -8,6 +8,7 @@
>  #ifndef _LINUX_ACPI_H
>  #define _LINUX_ACPI_H
>
> +#include <linux/cleanup.h>
>  #include <linux/errno.h>
>  #include <linux/ioport.h>      /* for struct resource */
>  #include <linux/resource_ext.h>
> @@ -221,6 +222,17 @@ void acpi_reserve_initial_tables (void);
>  void acpi_table_init_complete (void);
>  int acpi_table_init (void);
>
> +static inline struct acpi_table_header *acpi_get_table_ret(char *signature, u32 instance)

Maybe call this acpi_get_table_pointer() ?

> +{
> +       struct acpi_table_header *table;
> +       int status = acpi_get_table(signature, instance, &table);
> +
> +       if (ACPI_FAILURE(status))
> +               return ERR_PTR(-ENOENT);
> +       return table;
> +}
> +DEFINE_FREE(acpi_put_table, struct acpi_table_header *, if (!IS_ERR_OR_NULL(_T)) acpi_put_table(_T))
> +
>  int acpi_table_parse(char *id, acpi_tbl_table_handler handler);
>  int __init_or_acpilib acpi_table_parse_entries(char *id,
>                 unsigned long table_size, int entry_id,
> --