linux-kernel - Re: [PATCH v2 2/2] efi/fdt: Simplify get

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Date:   Mon, 5 Nov 2018 13:41:27 +0100
From:   Ard Biesheuvel <ard.biesheuvel@...aro.org>
To:     Julien Thierry <julien.thierry@....com>
Cc:     linux-efi <linux-efi@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Joe Perches <joe@...ches.com>
Subject: Re: [PATCH v2 2/2] efi/fdt: Simplify get_fdt flow

On 29 October 2018 at 11:15, Julien Thierry <julien.thierry@....com> wrote:
> Reorganize get_fdt lookup loop, clearly showing that:
> - Nothing is done for table entries that do not have fdt_guid
> - Once an entry with fdt_guid is found, break out of the loop
>
> No functional changes.
>
> Signed-off-by: Julien Thierry <julien.thierry@....com>
> Suggested-by: Joe Perches <joe@...ches.com>
> Cc: Ard Biesheuvel <ard.biesheuvel@...aro.org>
> ---
>  drivers/firmware/efi/libstub/fdt.c | 25 +++++++++++++------------
>  1 file changed, 13 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/firmware/efi/libstub/fdt.c b/drivers/firmware/efi/libstub/fdt.c
> index 8b6696e..5b7e2b3 100644
> --- a/drivers/firmware/efi/libstub/fdt.c
> +++ b/drivers/firmware/efi/libstub/fdt.c
> @@ -366,23 +366,24 @@ void *get_fdt(efi_system_table_t *sys_table, unsigned long *fdt_size)
>  {
>         efi_guid_t fdt_guid = DEVICE_TREE_GUID;
>         efi_config_table_t *tables;
> -       void *fdt;
>         int i;
>
> -       tables = (efi_config_table_t *) sys_table->tables;
> -       fdt = NULL;
> +       tables = (efi_config_table_t *)sys_table->tables;
>
>         for (i = 0; i < sys_table->nr_tables; i++) {
> -               if (efi_guidcmp(tables[i].guid, fdt_guid) == 0) {
> -                       fdt = (void *) tables[i].table;
> -                       if (fdt_check_header(fdt) != 0) {
> -                               pr_efi_err(sys_table, "Invalid header detected on UEFI supplied FDT, ignoring ...\n");
> -                               return NULL;
> -                       }
> -                       *fdt_size = fdt_totalsize(fdt);
> -                       break;
> +               void *fdt;
> +
> +               if (efi_guidcmp(tables[i].guid, fdt_guid) != 0)
> +                       continue;
> +
> +               fdt = (void *) tables[i].table;
> +               if (fdt_check_header(fdt) != 0) {
> +                       pr_efi_err(sys_table, "Invalid header detected on UEFI supplied FDT, ignoring ...\n");
> +                       return NULL;
>                 }
> +               *fdt_size = fdt_totalsize(fdt);
> +               return fdt;
>         }
>
> -       return fdt;
> +       return NULL;
>  }
> --
> 1.9.1
>

Queued in efi/next

Thanks.