[PATCH] genirq: i386 irq: Dynamic irq support

The current implementation of create_irq() is a hack but it is the current
hack that msi.c uses, and unfortunately the ``generic'' apic msi ops depend on
this hack.  Thus we are stuck this hack of assuming irq == vector until the
depencencies in the generic msi code are removed.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rajesh Shah <rajesh.shah@intel.com>
Cc: Andi Kleen <ak@muc.de>
Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 48 insertions, 0 deletions

diff --git a/arch/i386/kernel/io_apic.c b/arch/i386/kernel/io_apic.c
index b3b01894ca69..fca689cfb0c9 100644
--- a/arch/i386/kernel/io_apic.c
+++ b/arch/i386/kernel/io_apic.c
@@ -2483,6 +2483,54 @@ static int __init ioapic_init_sysfs(void)
 
 device_initcall(ioapic_init_sysfs);
 
+#ifdef CONFIG_PCI_MSI
+/*
+ * Dynamic irq allocate and deallocation for MSI
+ */
+int create_irq(void)
+{
+        /* Hack of the day: irq == vector.
+         *
+         * Ultimately this will be be more general,
+         * and not depend on the irq to vector identity mapping.
+         * But this version is needed until msi.c can cope with
+         * the more general form.
+         */
+        int irq, vector;
+        unsigned long flags;
+        vector = assign_irq_vector(AUTO_ASSIGN);
+        irq = vector;
+
+        if (vector >= 0) {
+                struct irq_desc *desc;
+
+                spin_lock_irqsave(&vector_lock, flags);
+                vector_irq[vector] = irq;
+                irq_vector[irq] = vector;
+                spin_unlock_irqrestore(&vector_lock, flags);
+
+                set_intr_gate(vector, interrupt[irq]);
+
+                dynamic_irq_init(irq);
+        }
+        return irq;
+}
+
+void destroy_irq(unsigned int irq)
+{
+        unsigned long flags;
+        unsigned int vector;
+
+        dynamic_irq_cleanup(irq);
+
+        spin_lock_irqsave(&vector_lock, flags);
+        vector = irq_vector[irq];
+        vector_irq[vector] = -1;
+        irq_vector[irq] = 0;
+        spin_unlock_irqrestore(&vector_lock, flags);
+}
+#endif /* CONFIG_PCI_MSI */
+
 /* --------------------------------------------------------------------------
                           ACPI-based IOAPIC Configuration
    -------------------------------------------------------------------------- */