[Xen-devel] [PATCH 09/10] xen/pci: Remove 'xen_allocate_pirq_gsi'.

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

In the past (2.6.38) the 'xen_allocate_pirq_gsi' would allocate
an entry in a Linux IRQ -> {XEN_IRQ, type, event, ..} array. All
of that has been removed in 2.6.39 and the Xen IRQ subsystem uses
an linked list that is populated when the call to
'xen_allocate_irq_gsi' (universally done from any of the xen_bind_*
calls) is done. The 'xen_allocate_pirq_gsi' is a NOP and there is
no need for it anymore so lets remove it.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
---
 arch/x86/pci/xen.c   |   37 ++++++++++++-------------------------
 drivers/xen/events.c |    5 -----
 include/xen/events.h |    2 --
 3 files changed, 12 insertions(+), 32 deletions(-)

diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index 6eddc52..f07c419 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -37,14 +37,8 @@ static int xen_pcifront_enable_irq(struct pci_dev *dev)
                         rc);
                return rc;
        }
-
-       rc = xen_allocate_pirq_gsi(gsi);
-       if (rc < 0) {
-               dev_warn(&dev->dev, "Xen PCI: failed to allocate a PIRQ for 
GSI%d: %d\n",
-                        gsi, rc);
-               return rc;
-       }
-       pirq = rc;
+       /* In PV DomU the Xen PCI backend puts the PIRQ in the interrupt line.*/
+       pirq = gsi;
 
        if (gsi < NR_IRQS_LEGACY)
                share = 0;
@@ -63,18 +57,16 @@ static int xen_pcifront_enable_irq(struct pci_dev *dev)
 
 #ifdef CONFIG_ACPI
 static int xen_register_pirq(u32 gsi, int gsi_override, int triggering,
-                            bool alloc_pirq)
+                            bool set_pirq)
 {
        int rc, pirq = -1, irq = -1;
        struct physdev_map_pirq map_irq;
        int shareable = 0;
        char *name;
 
-       if (alloc_pirq) {
-               pirq = xen_allocate_pirq_gsi(gsi);
-               if (pirq < 0)
-                       goto out;
-       }
+       if (set_pirq)
+               pirq = gsi;
+
        map_irq.domid = DOMID_SELF;
        map_irq.type = MAP_PIRQ_TYPE_GSI;
        map_irq.index = gsi;
@@ -112,8 +104,8 @@ static int acpi_register_gsi_xen_hvm(struct device *dev, 
u32 gsi,
        if (!xen_hvm_domain())
                return -1;
 
-       return xen_register_pirq(gsi, -1 /* no GSI override */,
-                                trigger, false /* no PIRQ allocation */);
+       return xen_register_pirq(gsi, -1 /* no GSI override */, trigger,
+                                false /* no mapping of GSI to PIRQ */);
 }
 
 #ifdef CONFIG_XEN_DOM0
@@ -430,7 +422,7 @@ static __init void xen_setup_acpi_sci(void)
 
 int __init pci_xen_initial_domain(void)
 {
-       int pirq, irq;
+       int irq;
 
 #ifdef CONFIG_PCI_MSI
        x86_msi.setup_msi_irqs = xen_initdom_setup_msi_irqs;
@@ -447,16 +439,11 @@ int __init pci_xen_initial_domain(void)
 
                xen_register_pirq(irq, -1 /* no GSI override */,
                        trigger ? ACPI_LEVEL_SENSITIVE : ACPI_EDGE_SENSITIVE,
-                       true /* allocate IRQ */);
+                       true /* Map GSI to PIRQ */);
        }
        if (0 == nr_ioapics) {
-               for (irq = 0; irq < NR_IRQS_LEGACY; irq++) {
-                       pirq = xen_allocate_pirq_gsi(irq);
-                       if (WARN(pirq < 0,
-                                "Could not allocate PIRQ for legacy 
interrupt\n"))
-                               break;
-                       irq = xen_bind_pirq_gsi_to_irq(irq, pirq, 0, "xt-pic");
-               }
+               for (irq = 0; irq < NR_IRQS_LEGACY; irq++)
+                       xen_bind_pirq_gsi_to_irq(irq, irq, 0, "xt-pic");
        }
        return 0;
 }
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 23f1b81..da70f5c 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -615,11 +615,6 @@ static int find_irq_by_gsi(unsigned gsi)
        return -1;
 }
 
-int xen_allocate_pirq_gsi(unsigned gsi)
-{
-       return gsi;
-}
-
 /*
  * Do not make any assumptions regarding the relationship between the
  * IRQ number returned here and the Xen pirq argument.
diff --git a/include/xen/events.h b/include/xen/events.h
index 9af21e1..d287997 100644
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -74,8 +74,6 @@ int xen_set_callback_via(uint64_t via);
 void xen_evtchn_do_upcall(struct pt_regs *regs);
 void xen_hvm_evtchn_do_upcall(void);
 
-/* Allocate a pirq for a physical interrupt, given a gsi. */
-int xen_allocate_pirq_gsi(unsigned gsi);
 /* Bind a pirq for a physical interrupt to an irq. */
 int xen_bind_pirq_gsi_to_irq(unsigned gsi,
                             unsigned pirq, int shareable, char *name);
-- 
1.7.4.1


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