Commit 5cad61a6 authored Feb 18, 2011 by Ian Campbell Committed by Konrad Rzeszutek Wilk Mar 10, 2011

xen: events: assume PHYSDEVOP_get_free_pirq exists



The find_unbound_pirq is called only from xen_allocate_pirq_msi and
only if alloc_pirq is true. The only caller which does this is
xen_hvm_setup_msi_irqs. The use of this function is gated, in
pci_xen_hvm_init, on XENFEAT_hvm_pirqs.

The PHYSDEVOP_get_free_pirq interfaces was added to the hypervisor in
22410:be96f6058c05 while XENFEAT_hvm_pirqs was added a couple of
minutes prior in 22409:6663214f06ac. Therefore we do not need to
concern ourselves with hypervisors which support XENFEAT_hvm_pirqs but
not PHYSDEVOP_get_free_pirq.

This eliminates the fallback path in find_unbound_pirq which walks to
pirq_to_irq array looking for a free pirq. Unlike the
PHYSDEVOP_get_free_pirq interface this fallback only looks up a free
pirq but does not reserve it. Removing this fallback will simplify
locking in the future.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

parent 9a626612

drivers/xen/events.c

+6 −9

Original line number	Diff line number	Diff line
		@@ -649,19 +649,16 @@ out:

		static int find_unbound_pirq(int type)
		{
		int rc, i;
		int rc;
		struct physdev_get_free_pirq op_get_free_pirq;
		op_get_free_pirq.type = type;

		op_get_free_pirq.type = type;
		rc = HYPERVISOR_physdev_op(PHYSDEVOP_get_free_pirq, &op_get_free_pirq);
		if (!rc)
		return op_get_free_pirq.pirq;

		for (i = 0; i < nr_irqs; i++) {
		if (pirq_to_irq[i] < 0)
		return i;
		}
		return -1;
		WARN_ONCE(rc == -ENOSYS,
		"hypervisor does not support the PHYSDEVOP_get_free_pirq interface\n");

		return rc ? -1 : op_get_free_pirq.pirq;
		}

		int xen_allocate_pirq_msi(char name, int pirq, int alloc_pirq)