xen: simplify evtchn_do_upcall() call maze

There are several functions involved for performing the functionality
of evtchn_do_upcall():

- __xen_evtchn_do_upcall() doing the real work
- xen_hvm_evtchn_do_upcall() just being a wrapper for
  __xen_evtchn_do_upcall(), exposed for external callers
- xen_evtchn_do_upcall() calling __xen_evtchn_do_upcall(), too, but
  without any user

Simplify this maze by:

- removing the unused xen_evtchn_do_upcall()
- removing xen_hvm_evtchn_do_upcall() as the only left caller of
  __xen_evtchn_do_upcall(), while renaming __xen_evtchn_do_upcall() to
  xen_evtchn_do_upcall()

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Juergen Gross <jgross@suse.com>

arch/arm/xen/enlighten.c

@@ -207,7 +207,7 @@ static void xen_power_off(void)
 
 static irqreturn_t xen_arm_callback(int irq, void *arg)
 {
-	xen_hvm_evtchn_do_upcall();
+	xen_evtchn_do_upcall();
 	return IRQ_HANDLED;
 }
 

arch/x86/entry/common.c

@@ -294,7 +294,7 @@ static void __xen_pv_evtchn_do_upcall(struct pt_regs *regs)
 
 	inc_irq_stat(irq_hv_callback_count);
 
-	xen_hvm_evtchn_do_upcall();
+	xen_evtchn_do_upcall();
 
 	set_irq_regs(old_regs);
 }

arch/x86/xen/enlighten.c

@@ -32,7 +32,7 @@ EXPORT_SYMBOL_GPL(hypercall_page);
  * &HYPERVISOR_shared_info->vcpu_info[cpu]. See xen_hvm_init_shared_info
  * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info
  * but during boot it is switched to point to xen_vcpu_info.
- * The pointer is used in __xen_evtchn_do_upcall to acknowledge pending events.
+ * The pointer is used in xen_evtchn_do_upcall to acknowledge pending events.
  */
 DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);
 DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info);

arch/x86/xen/enlighten_hvm.c

@@ -136,7 +136,7 @@ DEFINE_IDTENTRY_SYSVEC(sysvec_xen_hvm_callback)
 
 	inc_irq_stat(irq_hv_callback_count);
 
-	xen_hvm_evtchn_do_upcall();
+	xen_evtchn_do_upcall();
 
 	set_irq_regs(old_regs);
 }

drivers/xen/events/events_base.c

@@ -1704,7 +1704,7 @@ void handle_irq_for_port(evtchn_port_t port, struct evtchn_loop_ctrl *ctrl)
 	generic_handle_irq(irq);
 }
 
-static int __xen_evtchn_do_upcall(void)
+int xen_evtchn_do_upcall(void)
 {
 	struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu);
 	int ret = vcpu_info->evtchn_upcall_pending ? IRQ_HANDLED : IRQ_NONE;
@@ -1735,24 +1735,7 @@ static int __xen_evtchn_do_upcall(void)
 
 	return ret;
 }
-
-void xen_evtchn_do_upcall(struct pt_regs *regs)
-{
-	struct pt_regs *old_regs = set_irq_regs(regs);
-
-	irq_enter();
-
-	__xen_evtchn_do_upcall();
-
-	irq_exit();
-	set_irq_regs(old_regs);
-}
-
-int xen_hvm_evtchn_do_upcall(void)
-{
-	return __xen_evtchn_do_upcall();
-}
-EXPORT_SYMBOL_GPL(xen_hvm_evtchn_do_upcall);
+EXPORT_SYMBOL_GPL(xen_evtchn_do_upcall);
 
 /* Rebind a new event channel to an existing irq. */
 void rebind_evtchn_irq(evtchn_port_t evtchn, int irq)

drivers/xen/platform-pci.c

@@ -64,7 +64,7 @@ static uint64_t get_callback_via(struct pci_dev *pdev)
 
 static irqreturn_t do_hvm_evtchn_intr(int irq, void *dev_id)
 {
-	return xen_hvm_evtchn_do_upcall();
+	return xen_evtchn_do_upcall();
 }
 
 static int xen_allocate_irq(struct pci_dev *pdev)

include/xen/events.h

@@ -105,8 +105,7 @@ int irq_from_virq(unsigned int cpu, unsigned int virq);
 evtchn_port_t evtchn_from_irq(unsigned irq);
 
 int xen_set_callback_via(uint64_t via);
-void xen_evtchn_do_upcall(struct pt_regs *regs);
-int xen_hvm_evtchn_do_upcall(void);
+int xen_evtchn_do_upcall(void);
 
 /* Bind a pirq for a physical interrupt to an irq. */
 int xen_bind_pirq_gsi_to_irq(unsigned gsi,