[PATCH] x86_64: serialize assign_irq_vector() use of static variables

Since assign_irq_vector() can be called at runtime, its access of static
variables should be protected by a lock.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 18 insertions, 6 deletions

diff --git a/arch/i386/kernel/io_apic.c b/arch/i386/kernel/io_apic.c
index a62df3e764c5..43ffdd012d26 100644
--- a/arch/i386/kernel/io_apic.c
+++ b/arch/i386/kernel/io_apic.c
@@ -50,6 +50,7 @@ atomic_t irq_mis_count;
 static struct { int pin, apic; } ioapic_i8259 = { -1, -1 };
 
 static DEFINE_SPINLOCK(ioapic_lock);
+static DEFINE_SPINLOCK(vector_lock);
 
 int timer_over_8254 __initdata = 1;
 
@@ -1161,10 +1162,16 @@ u8 irq_vector[NR_IRQ_VECTORS] __read_mostly = { FIRST_DEVICE_VECTOR , 0 };
 int assign_irq_vector(int irq)
 {
         static int current_vector = FIRST_DEVICE_VECTOR, offset = 0;
+        int vector;
+
+        BUG_ON(irq != AUTO_ASSIGN && (unsigned)irq >= NR_IRQ_VECTORS);
+
+        spin_lock(&vector_lock);
 
-        BUG_ON(irq >= NR_IRQ_VECTORS);
-        if (irq != AUTO_ASSIGN && IO_APIC_VECTOR(irq) > 0)
+        if (irq != AUTO_ASSIGN && IO_APIC_VECTOR(irq) > 0) {
+                spin_unlock(&vector_lock);
                 return IO_APIC_VECTOR(irq);
+        }
 next:
         current_vector += 8;
         if (current_vector == SYSCALL_VECTOR)
@@ -1172,16 +1179,21 @@ next:
 
         if (current_vector >= FIRST_SYSTEM_VECTOR) {
                 offset++;
-                if (!(offset%8))
+                if (!(offset%8)) {
+                        spin_unlock(&vector_lock);
                         return -ENOSPC;
+                }
                 current_vector = FIRST_DEVICE_VECTOR + offset;
         }
 
-        vector_irq[current_vector] = irq;
+        vector = current_vector;
+        vector_irq[vector] = irq;
         if (irq != AUTO_ASSIGN)
-                IO_APIC_VECTOR(irq) = current_vector;
+                IO_APIC_VECTOR(irq) = vector;
+
+        spin_unlock(&vector_lock);
 
-        return current_vector;
+        return vector;
 }
 
 static struct hw_interrupt_type ioapic_level_type;