Re: [PATCH V7 1/8] ACPI: I/O Remapping Table (IORT) initial support

[Hanjun Guo]

Hi Tomasz,

Sorry for jumping out late, just one comment below.

On 2016/6/20 19:02, Tomasz Nowicki wrote:
> IORT shows representation of IO topology for ARM based systems.
> It describes how various components are connected together on
> parent-child basis e.g. PCI RC -> SMMU -> ITS. Also see IORT spec.
>
> Initial support allows to detect IORT table presence and save its
> root pointer obtained through acpi_get_table(). The pointer validity
> depends on acpi_gbl_permanent_mmap because if acpi_gbl_permanent_mmap
> is not set while using IORT nodes we would dereference unmapped pointers.
>
> For the aforementioned reason call iort_table_detect() from acpi_init()
> which guarantees acpi_gbl_permanent_mmap to be set at that point.
>
> Add generic helpers which are helpful for scanning and retrieving
> information from IORT table content. List of the most important helpers:
> - iort_find_dev_node() finds IORT node for a given device
> - iort_node_map_rid() maps device RID and returns IORT node which provides
>   final translation
>
> Signed-off-by: Tomasz Nowicki <tn@xxxxxxxxxxxx>
> ---
>  drivers/acpi/Kconfig  |   3 +
>  drivers/acpi/Makefile |   1 +
>  drivers/acpi/bus.c    |   2 +
>  drivers/acpi/iort.c   | 220 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/iort.h  |  30 +++++++

[...]

> +static acpi_status
> +iort_match_node_callback(struct acpi_iort_node *node, void *context)
> +{
> +	struct device *dev = context;
> +
> +	switch (node->type) {
> +	case ACPI_IORT_NODE_NAMED_COMPONENT: {
> +		struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };

ACPI_ALLOCATE_BUFFER is used here, so ...

> +		struct acpi_device *adev = to_acpi_device_node(dev->fwnode);
> +		struct acpi_iort_named_component *ncomp;
> +
> +		if (!adev)
> +			break;
> +
> +		ncomp = (struct acpi_iort_named_component *)node->node_data;
> +
> +		if (ACPI_FAILURE(acpi_get_name(adev->handle,
> +					       ACPI_FULL_PATHNAME, &buffer))) {
> +			dev_warn(dev, "Can't get device full path name\n");
> +			break;
> +		}
> +
> +		if (!strcmp(ncomp->device_name, (char *)buffer.pointer))
> +			return AE_OK;

... we need to kfree(buffer.pointer) before we return or break.

With this fixed,

Reviewed-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>

Thanks
Hanjun

> +
> +		break;
> +	}