Re: [RFC PATCH 04/15] libfdt: fdt_rw: Introduce fdt_downgrade_version()

[David Gibson <david@gibson.dropbear.id.au>]

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On Tue, Feb 10, 2026 at 06:33:32PM +0100, Herve Codina wrote:
> Current code perform a version downgrade at one place only, the end of
> fdt_rw_probe_().
> 
> In order to offer a finer grain and choose to downgrade or not depending
> on the exact writes done, introduce fdt_downgrade_version() to perform
> the downgrade operation.
> 
> The modification doesn't introduce any functional changes.
> 
> Signed-off-by: Herve Codina <herve.codina@bootlin.com>

Applied, thanks.

> ---
>  libfdt/fdt_rw.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/libfdt/fdt_rw.c b/libfdt/fdt_rw.c
> index 7475caf..90ea14e 100644
> --- a/libfdt/fdt_rw.c
> +++ b/libfdt/fdt_rw.c
> @@ -22,6 +22,12 @@ static int fdt_blocks_misordered_(const void *fdt,
>  		    (fdt_off_dt_strings(fdt) + fdt_size_dt_strings(fdt)));
>  }
>  
> +static void fdt_downgrade_version(void *fdt)
> +{
> +	if (!can_assume(LATEST) && fdt_version(fdt) > FDT_LAST_SUPPORTED_VERSION)
> +		fdt_set_version(fdt, FDT_LAST_SUPPORTED_VERSION);
> +}
> +
>  static int fdt_rw_probe_(void *fdt)
>  {
>  	if (can_assume(VALID_DTB))
> @@ -33,9 +39,8 @@ static int fdt_rw_probe_(void *fdt)
>  	if (fdt_blocks_misordered_(fdt, sizeof(struct fdt_reserve_entry),
>  				   fdt_size_dt_struct(fdt)))
>  		return -FDT_ERR_BADLAYOUT;
> -	if (!can_assume(LATEST) && fdt_version(fdt) > 17)
> -		fdt_set_version(fdt, 17);
>  
> +	fdt_downgrade_version(fdt);
>  	return 0;
>  }
>  
> -- 
> 2.52.0
> 
> 

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

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