On 15/09/15 11:58, Tomasz Nowicki wrote:

On 14.09.2015 18:44, Marc Zyngier wrote:

quoted

struct device_node is very much DT specific, and the original authors
of the irqdomain subsystem recognized that tie, and went as far as
mentionning that this could be replaced by some "void *token",
should another firmware infrastructure be using it.

As we move ACPI on arm64 towards this model too, it makes a lot of sense
to perform that particular move.

We replace "struct device_node *of_node" with "void *domain_token", which
is a benign enough transformation. A non DT user of irqdomain can now
identify its domains using this pointer.

Also, in order to prevent the introduction of sideband type information,
only DT is allowed to store a valid kernel pointer in domain_token
(a pointer that passes the virt_addr_valid() test will be considered
as a valid device_node).

non-DT users that wish to store valid pointers in domain_token are
required to use another structure such as an IDR.

Signed-off-by: Marc Zyngier <redacted>
---
  include/linux/irqdomain.h | 68 +++++++++++++++++++-----------------
  kernel/irq/irqdomain.c    | 89 ++++++++++++++++++++++++++++++++++-------------
  2 files changed, 101 insertions(+), 56 deletions(-)

[...]

quoted

-struct irq_domain *__irq_domain_add(struct device_node *of_node, int size,
+struct irq_domain *__irq_domain_add(void *domain_token, int size,
  				    irq_hw_number_t hwirq_max, int direct_max,
  				    const struct irq_domain_ops *ops,
  				    void *host_data)
  {
+	struct device_node *of_node;
  	struct irq_domain *domain;

+	of_node = irq_domain_token_to_of_node(domain_token);
  	domain = kzalloc_node(sizeof(*domain) + (sizeof(unsigned int) * size),
  			      GFP_KERNEL, of_node_to_nid(of_node));

While we are here, do you think it makes sense to abstract 
of_node_to_nid as well? Then we would really remove device_node 
dependency for irqdomain.

Not quite sure yet. I've decided to completely ignore the whole NUMA
thing for the time being. This is a performance issue, not a
functionality problem.

Once we have something that actually makes sense, we can have a look.

	M.
-- 
Jazz is not dead. It just smells funny...