linux-kernel - Re: [PATCH 2/3] ACPI: fix acpi_parse_entries

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Date:	Fri, 1 Jul 2016 23:32:11 +0200
From:	"Rafael J. Wysocki" <rafael@...nel.org>
To:	Al Stone <ahs3@...hat.com>
Cc:	ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	"Rafael J . Wysocki" <rjw@...ysocki.net>,
	Len Brown <lenb@...nel.org>
Subject: Re: [PATCH 2/3] ACPI: fix acpi_parse_entries_array() so it traverses
 all subtables

On Fri, Jul 1, 2016 at 11:21 PM, Al Stone <ahs3@...hat.com> wrote:
> Without this patch, the acpi_parse_entries_array() function will return
> the very first time there is any error found in either the array of
> callback functions or if one of the callbacks returns an non-zero value.
> However, the array of callbacks could still have valid entries further
> on in the array, or the callbacks may be able to process subsequent
> subtables without error.  The change here makes the function consistent
> with its description so that it will properly return the sum of all
> matching entries for all proc handlers, instead of stopping abruptly
> as it does today.

I'm not sure I follow.

You seem to be saying that the function should process all of the
subtables etc even though errors have been found for some of them, but
it still will return an error in the end if there are any errors.  How
exactly does it help to continue processing in case of an error, then?

> Signed-off-by: Al Stone <ahs3@...hat.com>
> Cc: Rafael J. Wysocki <rjw@...ysocki.net>
> Cc: Len Brown <lenb@...nel.org>
> ---
>  drivers/acpi/tables.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
> index 3e167b4..76c07ed 100644
> --- a/drivers/acpi/tables.c
> +++ b/drivers/acpi/tables.c
> @@ -246,6 +246,7 @@ acpi_parse_entries_array(char *id, unsigned long table_size,
>         struct acpi_subtable_header *entry;
>         unsigned long table_end;
>         int count = 0;
> +       int errs_found = 0;
>         int i;
>
>         if (acpi_disabled)
> @@ -278,8 +279,10 @@ acpi_parse_entries_array(char *id, unsigned long table_size,
>                         if (entry->type != proc[i].id)
>                                 continue;
>                         if (!proc[i].handler ||
> -                            proc[i].handler(entry, table_end))
> -                               return -EINVAL;
> +                            proc[i].handler(entry, table_end)) {
> +                               errs_found++;
> +                               continue;
> +                       }
>
>                         proc[i].count++;
>                         break;
> @@ -305,7 +308,7 @@ acpi_parse_entries_array(char *id, unsigned long table_size,
>                         id, proc->id, count - max_entries, count);
>         }
>
> -       return count;
> +       return (errs_found) ? -EINVAL : count;
>  }
>
>  int __init
> --