On 6/8/2016 2:50 AM, Gavin Shan wrote:
> The function is unflattening device sub-tree blob if @dad passed to
> the function is valid. Currently, this functionality is used by PPC
> PowerNV PCI hotplug driver only. There are possibly multiple nodes
> in the first level of depth, fdt_next_node() bails immediately when
> @depth becomes negative before the second device node can be probed
> successfully. It leads to the device nodes except the first one won't
> be unflattened successfully.
>
> This fixes the issue by setting the initial depth (@inital_depth) to
> 1 when this function is called to unflatten device sub-tree blob. No
> logic changes when this function is used to unflatten non-sub-tree
> blob.
>
> Cc: Rhyland Klein <rklein@xxxxxxxxxx>
> Fixes: 78c44d910 ("drivers/of: Fix depth when unflattening devicetree")
> Signed-off-by: Gavin Shan <gwshan@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/of/fdt.c | 15 +++++++++++++--
> 1 file changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> index 14f2f8c..9d70316 100644
> --- a/drivers/of/fdt.c
> +++ b/drivers/of/fdt.c
> @@ -395,7 +395,7 @@ static int unflatten_dt_nodes(const void *blob,
> struct device_node **nodepp)
> {
> struct device_node *root;
> - int offset = 0, depth = 0;
> + int offset = 0, depth = 0, initial_depth = 0;
> #define FDT_MAX_DEPTH 64
> unsigned int fpsizes[FDT_MAX_DEPTH];
> struct device_node *nps[FDT_MAX_DEPTH];
> @@ -408,8 +408,19 @@ static int unflatten_dt_nodes(const void *blob,
> root = dad;
> fpsizes[depth] = dad ? strlen(of_node_full_name(dad)) : 0;
> nps[depth] = dad;
> +
> + /*
> + * We're unflattening device sub-tree if @dad is valid. There are
> + * possibly multiple nodes in the first level of depth. We need
> + * set @depth to 1 to make fdt_next_node() happy as it bails
> + * immediately when negative @depth is found. Otherwise, the device
> + * nodes except the first one won't be unflattened successfully.
> + */
> + if (dad)
> + depth = initial_depth = 1;
> +
> for (offset = 0;
> - offset >= 0 && depth >= 0;
> + offset >= 0 && depth >= initial_depth;
> offset = fdt_next_node(blob, offset, &depth)) {
> if (WARN_ON_ONCE(depth >= FDT_MAX_DEPTH))
> continue;
>
I tested this and it seems to be working fine for me.
Tested-by: Rhyland Klein <rklein@xxxxxxxxxx>
-rhyland
--
nvpublic
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