x86/hpet: Use proper hpet device number for MSI allocation

hpet_assign_irq() is called with hpet_device->num as "hardware
interrupt number", but hpet_device->num is initialized after the
interrupt has been assigned, so it's always 0. As a consequence only
the first MSI allocation succeeds, the following ones fail because the
"hardware interrupt number" already exists.

Move the initialization of dev->num and other fields before the call
to hpet_assign_irq(), which is the ordering before the offending
commit which introduced that regression.

Fixes: "3cb96f0c9733 x86/hpet: Enhance HPET IRQ to support hierarchical irqdomains"
Reported-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1506211635010.4107@nanos
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>

diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index c47aab3..10757d0 100644 (file)
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -577,16 +577,17 @@ static void hpet_msi_capability_lookup(unsigned int start_timer)
                if (!(cfg & HPET_TN_FSB_CAP))
                        continue;
 
+               hdev->flags = 0;
+               if (cfg & HPET_TN_PERIODIC_CAP)
+                       hdev->flags |= HPET_DEV_PERI_CAP;
+               sprintf(hdev->name, "hpet%d", i);
+               hdev->num = i;
+
                irq = hpet_assign_irq(hpet_domain, hdev, hdev->num);
                if (irq <= 0)
                        continue;
 
-               sprintf(hdev->name, "hpet%d", i);
-               hdev->num = i;
                hdev->irq = irq;
-               hdev->flags = 0;
-               if (cfg & HPET_TN_PERIODIC_CAP)
-                       hdev->flags |= HPET_DEV_PERI_CAP;
                hdev->flags |= HPET_DEV_FSB_CAP;
                hdev->flags |= HPET_DEV_VALID;
                num_timers_used++;