[Xen-devel] [PATCH v2 3/8] xen: arm: Refactor route_irq_to_guest

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

Split out the bit which allocates the struct irqaction and calls
__setup_irq into a new function (setup_guest_irq). I'm going to want
to call this a second time in a subsequent patch.

Note that the action is now allocated and initialised with the desc
lock held (since it is taken by the caller). I don't think this is an
issue (and avoiding this would make things more complex)

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
v2: New patch (maybe, it's been a while...)
---
 xen/arch/arm/irq.c | 104 +++++++++++++++++++++++++++++++----------------------
 1 file changed, 61 insertions(+), 43 deletions(-)

diff --git a/xen/arch/arm/irq.c b/xen/arch/arm/irq.c
index 5031777..6918438 100644
--- a/xen/arch/arm/irq.c
+++ b/xen/arch/arm/irq.c
@@ -394,61 +394,24 @@ bool_t is_assignable_irq(unsigned int irq)
     return ((irq >= NR_LOCAL_IRQS) && (irq < gic_number_lines()));
 }
 
-/*
- * Route an IRQ to a specific guest.
- * For now only SPIs are assignable to the guest.
- */
-int route_irq_to_guest(struct domain *d, unsigned int virq,
-                       unsigned int irq, const char * devname)
+static int setup_guest_irq(struct irq_desc *desc, unsigned int virq,
+                           unsigned int irqflags,
+                           struct irq_guest *info, const char *devname)
 {
+    const unsigned irq = desc->irq;
     struct irqaction *action;
-    struct irq_guest *info;
-    struct irq_desc *desc;
-    unsigned long flags;
     int retval = 0;
 
-    if ( virq >= vgic_num_irqs(d) )
-    {
-        printk(XENLOG_G_ERR
-               "the vIRQ number %u is too high for domain %u (max = %u)\n",
-               irq, d->domain_id, vgic_num_irqs(d));
-        return -EINVAL;
-    }
-
-    /* Only routing to virtual SPIs is supported */
-    if ( virq < NR_LOCAL_IRQS )
-    {
-        printk(XENLOG_G_ERR "IRQ can only be routed to an SPI\n");
-        return -EINVAL;
-    }
-
-    if ( !is_assignable_irq(irq) )
-    {
-        printk(XENLOG_G_ERR "the IRQ%u is not routable\n", irq);
-        return -EINVAL;
-    }
-    desc = irq_to_desc(irq);
+    ASSERT(spin_is_locked(&desc->lock));
 
     action = xmalloc(struct irqaction);
     if ( !action )
         return -ENOMEM;
 
-    info = xmalloc(struct irq_guest);
-    if ( !info )
-    {
-        xfree(action);
-        return -ENOMEM;
-    }
-
-    info->d = d;
-    info->virq = virq;
-
     action->dev_id = info;
     action->name = devname;
     action->free_on_release = 1;
 
-    spin_lock_irqsave(&desc->lock, flags);
-
     if ( desc->arch.type == DT_IRQ_TYPE_INVALID )
     {
         printk(XENLOG_G_ERR "IRQ %u has not been configured\n", irq);
@@ -466,6 +429,7 @@ int route_irq_to_guest(struct domain *d, unsigned int virq,
      */
     if ( desc->action != NULL )
     {
+        struct domain *d = info->d;
         struct domain *ad = irq_get_domain(desc);
 
         if ( test_bit(_IRQ_GUEST, &desc->status) && d == ad )
@@ -493,6 +457,61 @@ int route_irq_to_guest(struct domain *d, unsigned int virq,
     if ( retval )
         goto out;
 
+    return 0;
+
+out:
+    xfree(action);
+    return retval;
+}
+
+/*
+ * Route an IRQ to a specific guest.
+ * For now only SPIs are assignable to the guest.
+ */
+int route_irq_to_guest(struct domain *d, unsigned int virq,
+                       unsigned int irq, const char * devname)
+{
+    struct irq_guest *info;
+    struct irq_desc *desc;
+    unsigned long flags;
+    int retval;
+
+    if ( virq >= vgic_num_irqs(d) )
+    {
+        printk(XENLOG_G_ERR
+               "the vIRQ number %u is too high for domain %u (max = %u)\n",
+               irq, d->domain_id, vgic_num_irqs(d));
+        return -EINVAL;
+    }
+
+    /* Only routing to virtual SPIs is supported */
+    if ( virq < NR_LOCAL_IRQS )
+    {
+        printk(XENLOG_G_ERR "IRQ can only be routed to an SPI\n");
+        return -EINVAL;
+    }
+
+    if ( !is_assignable_irq(irq) )
+    {
+        printk(XENLOG_G_ERR "the IRQ%u is not routable\n", irq);
+        return -EINVAL;
+    }
+
+    desc = irq_to_desc(irq);
+
+    info = xmalloc(struct irq_guest);
+    if ( !info )
+        return -ENOMEM;
+
+    info->d = d;
+    info->virq = virq;
+
+    spin_lock_irqsave(&desc->lock, flags);
+
+    retval = setup_guest_irq(desc, virq, flags, info, devname);
+    if ( retval )
+        goto out;
+
     retval = gic_route_irq_to_guest(d, virq, desc, GIC_PRI_IRQ);
 
     spin_unlock_irqrestore(&desc->lock, flags);
@@ -507,7 +526,6 @@ int route_irq_to_guest(struct domain *d, unsigned int virq,
 
 out:
     spin_unlock_irqrestore(&desc->lock, flags);
-    xfree(action);
 free_info:
     xfree(info);
 
-- 
2.1.4


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