x86: apic: Fix mismerge, add arch_probe_nr_irqs() again

Merge commit aef55d4922 mis-merged io_apic.c so we lost the
arch_probe_nr_irqs() method.

This caused subtle boot breakages (udev confusion likely
due to missing drivers) with certain configs.

Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <20100207210250.GB8256@jenkins.home.ifup.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 22 insertions, 0 deletions

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 979589881c80..72ac2a332993 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -3876,6 +3876,28 @@ void __init probe_nr_irqs_gsi(void)
         printk(KERN_DEBUG "nr_irqs_gsi: %d\n", nr_irqs_gsi);
 }
 
+#ifdef CONFIG_SPARSE_IRQ
+int __init arch_probe_nr_irqs(void)
+{
+        int nr;
+
+        if (nr_irqs > (NR_VECTORS * nr_cpu_ids))
+                nr_irqs = NR_VECTORS * nr_cpu_ids;
+
+        nr = nr_irqs_gsi + 8 * nr_cpu_ids;
+#if defined(CONFIG_PCI_MSI) || defined(CONFIG_HT_IRQ)
+        /*
+         * for MSI and HT dyn irq
+         */
+        nr += nr_irqs_gsi * 16;
+#endif
+        if (nr < nr_irqs)
+                nr_irqs = nr;
+
+        return 0;
+}
+#endif
+
 static int __io_apic_set_pci_routing(struct device *dev, int irq,
                                 struct io_apic_irq_attr *irq_attr)
 {