Re: [PATCH 4/8] powerpc/pseries: fix parsing of initial node path in update_dt_node

[Nathan Fontenot <nfont@linux.vnet.ibm.com>]

On 08/15/2013 12:23 AM, Tyrel Datwyler wrote:
> On the first call to ibm,update-properties for a node the first property
> returned is the full node path. Currently this is not parsed correctly by the
> update_dt_node function. Commit 2e9b7b0 attempted to fix this, but was
> incorrect as it made a wrong assumption about the layout of the first
> property in the work area. Further, if ibm,update-properties must be called
> multiple times for the same node this special property should only be skipped
> after the initial call. The first property descriptor returned consists of
> the property name, property value length, and property value. The property
> name is an empty string, property length is encoded in 4 byte integer, and
> the property value is the node path.
> 
> Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>

Acked-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>

> ---
>  arch/powerpc/platforms/pseries/mobility.c | 21 +++++++++++----------
>  1 file changed, 11 insertions(+), 10 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
> index 023e354..ed5426f 100644
> --- a/arch/powerpc/platforms/pseries/mobility.c
> +++ b/arch/powerpc/platforms/pseries/mobility.c
> @@ -161,18 +161,19 @@ static int update_dt_node(u32 phandle, s32 scope)
>  
>  		prop_data = rtas_buf + sizeof(*upwa);
>  
> -		/* The first element of the buffer is the path of the node
> -		 * being updated in the form of a 8 byte string length
> -		 * followed by the string. Skip past this to get to the
> -		 * properties being updated.
> +		/* On the first call to ibm,update-properties for a node the
> +		 * the first property value descriptor contains an empty
> +		 * property name, the property value length encoded as u32,
> +		 * and the property value is the node path being updated.
>  		 */
> -		vd = *prop_data++;
> -		prop_data += vd;
> +		if (*prop_data == 0) {
> +			prop_data++;
> +			vd = *(u32 *)prop_data;
> +			prop_data += vd + sizeof(vd);
> +			upwa->nprops--;
> +		}
>  
> -		/* The path we skipped over is counted as one of the elements
> -		 * returned so start counting at one.
> -		 */
> -		for (i = 1; i < upwa->nprops; i++) {
> +		for (i = 0; i < upwa->nprops; i++) {
>  			char *prop_name;
>  
>  			prop_name = prop_data;
>