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

[Tomasz Nowicki]

On 22.06.2016 12:50, Marc Zyngier wrote:
> On 21/06/16 08:12, Hanjun Guo wrote:
> > 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.
>
> For the record, I've queued this patch on top:
>
> diff --git a/drivers/acpi/iort.c b/drivers/acpi/iort.c
> index 496dcf6..3b9e55b 100644
> --- a/drivers/acpi/iort.c
> +++ b/drivers/acpi/iort.c
> @@ -158,11 +158,15 @@ iort_match_node_callback(struct acpi_iort_node *node, void *context)
>   		if (ACPI_FAILURE(acpi_get_name(adev->handle,
>   					       ACPI_FULL_PATHNAME, &buffer))) {
>   			dev_warn(dev, "Can't get device full path name\n");
> -			break;
> -		}
> +		} else {
> +			int match;
>
> -		if (!strcmp(ncomp->device_name, (char *)buffer.pointer))
> -			return AE_OK;
> +			match = !strcmp(ncomp->device_name, buffer.pointer);
> +			acpi_os_free(&buffer);
> +
> +			if (match)
> +				return AE_OK;
> +		}
>
>   		break;
>   	}
>
>
> assuming that Rafael is OK with the general approach, of course.

Thanks Marc. As Lorenzo pointed out, we need another fix for 
iort_node_map_rid(). Do you want me to refresh the whole series or this 
patch only?

Tomasz