x86/irq: simplify loop in unmap_domain_pirq

The for loop in unmap_domain_pirq is unnecessary complicated, with
several places where the index is incremented, and also different
exit conditions spread between the loop body.

Simplify it by looping over each possible PIRQ using the for loop
syntax, and remove all possible in-loop exit points.

No functional change intended.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

diff --git a/xen/arch/x86/irq.c b/xen/arch/x86/irq.c
index 032fe821675048fdd2ca7a23ed7ba42a8e9b80bc..a1693f92dd928fe7e81e43e448938512d4cc1ba6 100644 (file)
--- a/xen/arch/x86/irq.c
+++ b/xen/arch/x86/irq.c
@@ -2305,7 +2305,6 @@ done:
 /* The pirq should have been unbound before this call. */
 int unmap_domain_pirq(struct domain *d, int pirq)
 {
-    unsigned long flags;
     struct irq_desc *desc;
     int irq, ret = 0, rc;
     unsigned int i, nr = 1;
@@ -2356,11 +2355,23 @@ int unmap_domain_pirq(struct domain *d, int pirq)
     if ( msi_desc != NULL )
         pci_disable_msi(msi_desc);
 
-    spin_lock_irqsave(&desc->lock, flags);
-
-    for ( i = 0; ; )
+    for ( i = 0; i < nr; i++, info = pirq_info(d, pirq + i) )
     {
+        unsigned long flags;
+
+        if ( !info || info->arch.irq <= 0 )
+        {
+            printk(XENLOG_G_ERR "%pd: MSI pirq %d not mapped\n",
+                   d, pirq + i);
+            continue;
+        }
+        irq = info->arch.irq;
+        desc = irq_to_desc(irq);
+
+        spin_lock_irqsave(&desc->lock, flags);
+
         BUG_ON(irq != domain_pirq_to_irq(d, pirq + i));
+        BUG_ON(desc->msi_desc != msi_desc + i);
 
         if ( !forced_unbind )
             clear_domain_irq_pirq(d, irq, info);
@@ -2378,45 +2389,6 @@ int unmap_domain_pirq(struct domain *d, int pirq)
             desc->msi_desc = NULL;
         }
 
-        if ( ++i == nr )
-            break;
-
-        spin_unlock_irqrestore(&desc->lock, flags);
-
-        if ( !forced_unbind )
-           cleanup_domain_irq_pirq(d, irq, info);
-
-        rc = irq_deny_access(d, irq);
-        if ( rc )
-        {
-            printk(XENLOG_G_ERR
-                   "dom%d: could not deny access to IRQ%d (pirq %d)\n",
-                   d->domain_id, irq, pirq + i);
-            ret = rc;
-        }
-
-        do {
-            info = pirq_info(d, pirq + i);
-            if ( info && (irq = info->arch.irq) > 0 )
-                break;
-            printk(XENLOG_G_ERR "dom%d: MSI pirq %d not mapped\n",
-                   d->domain_id, pirq + i);
-        } while ( ++i < nr );
-
-        if ( i == nr )
-        {
-            desc = NULL;
-            break;
-        }
-
-        desc = irq_to_desc(irq);
-        BUG_ON(desc->msi_desc != msi_desc + i);
-
-        spin_lock_irqsave(&desc->lock, flags);
-    }
-
-    if ( desc )
-    {
         spin_unlock_irqrestore(&desc->lock, flags);
 
         if ( !forced_unbind )
@@ -2427,7 +2399,7 @@ int unmap_domain_pirq(struct domain *d, int pirq)
         {
             printk(XENLOG_G_ERR
                    "dom%d: could not deny access to IRQ%d (pirq %d)\n",
-                   d->domain_id, irq, pirq + nr - 1);
+                   d->domain_id, irq, pirq + i);
             ret = rc;
         }
     }