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>

1 files changed, 6 insertions, 5 deletions

diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index c47aab35a17e..10757d0a3fcf 100644
--- 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++;