[Xen-changelog] In both i386 and x86-64 Linux, using a static variable (and thus

[Xen patchbot -unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID c76daba31026e77d3b6cbae2164a3d5315f9273d
# Parent  f80709ba0e790af316c518eeb4ffab153801574f
In both i386 and x86-64 Linux, using a static variable (and thus 
having the potential of missing synchronization there,
as I suspect exists in native Linux) is not needed with the hypercall 
approach. In the hypervisor, the patch adds the
needed synchronization.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

diff -r f80709ba0e79 -r c76daba31026 
linux-2.6-xen-sparse/arch/i386/kernel/io_apic-xen.c
--- a/linux-2.6-xen-sparse/arch/i386/kernel/io_apic-xen.c       Thu Apr 20 
10:38:07 2006 +0100
+++ b/linux-2.6-xen-sparse/arch/i386/kernel/io_apic-xen.c       Thu Apr 20 
14:10:35 2006 +0100
@@ -1205,7 +1205,6 @@ u8 irq_vector[NR_IRQ_VECTORS] __read_mos
 
 int assign_irq_vector(int irq)
 {
-       static int current_vector = FIRST_DEVICE_VECTOR;
        physdev_op_t op;
 
        BUG_ON(irq >= NR_IRQ_VECTORS);
@@ -1216,13 +1215,12 @@ int assign_irq_vector(int irq)
        op.u.irq_op.irq = irq;
        if (HYPERVISOR_physdev_op(&op))
                return -ENOSPC;
-       current_vector = op.u.irq_op.vector;
-
-       vector_irq[current_vector] = irq;
+
+       vector_irq[op.u.irq_op.vector] = irq;
        if (irq != AUTO_ASSIGN)
-               IO_APIC_VECTOR(irq) = current_vector;
-
-       return current_vector;
+               IO_APIC_VECTOR(irq) = op.u.irq_op.vector;
+
+       return op.u.irq_op.vector;
 }
 
 #ifndef CONFIG_XEN
diff -r f80709ba0e79 -r c76daba31026 
linux-2.6-xen-sparse/arch/x86_64/kernel/io_apic-xen.c
--- a/linux-2.6-xen-sparse/arch/x86_64/kernel/io_apic-xen.c     Thu Apr 20 
10:38:07 2006 +0100
+++ b/linux-2.6-xen-sparse/arch/x86_64/kernel/io_apic-xen.c     Thu Apr 20 
14:10:35 2006 +0100
@@ -869,7 +869,6 @@ u8 irq_vector[NR_IRQ_VECTORS] __read_mos
 
 int assign_irq_vector(int irq)
 {
-       static int current_vector = FIRST_DEVICE_VECTOR;
        physdev_op_t op;
   
        BUG_ON(irq != AUTO_ASSIGN && (unsigned)irq >= NR_IRQ_VECTORS);
@@ -880,13 +879,12 @@ int assign_irq_vector(int irq)
        op.u.irq_op.irq = irq;
        if (HYPERVISOR_physdev_op(&op))
                return -ENOSPC;
-       current_vector = op.u.irq_op.vector;
-
-       vector_irq[current_vector] = irq;
+
+       vector_irq[op.u.irq_op.vector] = irq;
        if (irq != AUTO_ASSIGN)
-               IO_APIC_VECTOR(irq) = current_vector;
-
-       return current_vector;
+               IO_APIC_VECTOR(irq) = op.u.irq_op.vector;
+
+       return op.u.irq_op.vector;
 }
 
 extern void (*interrupt[NR_IRQS])(void);
diff -r f80709ba0e79 -r c76daba31026 xen/arch/x86/io_apic.c
--- a/xen/arch/x86/io_apic.c    Thu Apr 20 10:38:07 2006 +0100
+++ b/xen/arch/x86/io_apic.c    Thu Apr 20 14:10:35 2006 +0100
@@ -48,6 +48,7 @@ static struct { int pin, apic; } ioapic_
 static struct { int pin, apic; } ioapic_i8259 = { -1, -1 };
 
 static DEFINE_SPINLOCK(ioapic_lock);
+static DEFINE_SPINLOCK(vector_lock);
 
 int skip_ioapic_setup;
 
@@ -661,11 +662,17 @@ u8 irq_vector[NR_IRQ_VECTORS] __read_mos
 
 int assign_irq_vector(int irq)
 {
-    static int current_vector = FIRST_DYNAMIC_VECTOR, offset = 0;
+    static unsigned current_vector = FIRST_DYNAMIC_VECTOR, offset = 0;
+    unsigned vector;
 
     BUG_ON(irq >= NR_IRQ_VECTORS);
-    if (irq != AUTO_ASSIGN && IO_APIC_VECTOR(irq) > 0)
+    spin_lock(&vector_lock);
+
+    if (irq != AUTO_ASSIGN && IO_APIC_VECTOR(irq) > 0) {
+        spin_unlock(&vector_lock);
         return IO_APIC_VECTOR(irq);
+    }
+
 next:
     current_vector += 8;
 
@@ -679,16 +686,21 @@ next:
 
     if (current_vector > LAST_DYNAMIC_VECTOR) {
         offset++;
-        if (!(offset%8))
+        if (!(offset%8)) {
+            spin_unlock(&vector_lock);
             return -ENOSPC;
+        }
         current_vector = FIRST_DYNAMIC_VECTOR + offset;
     }
 
-    vector_irq[current_vector] = irq;
+    vector = current_vector;
+    vector_irq[vector] = irq;
     if (irq != AUTO_ASSIGN)
-        IO_APIC_VECTOR(irq) = current_vector;
-
-    return current_vector;
+        IO_APIC_VECTOR(irq) = vector;
+
+    spin_unlock(&vector_lock);
+
+    return vector;
 }
 
 static struct hw_interrupt_type ioapic_level_type;

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