xen/pci: Remove 'xen_allocate_pirq_gsi'.

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@oracle.com>

3 files changed, 12 insertions, 32 deletions

diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index 6eddc524603c..f07c419a616c 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 23f1b8166a2a..da70f5c32eb9 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 9af21e19545a..d287997d3eab 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);