Clearly for the adjusted BUG_ON()s to not yield false positives
num_hpets_used (rather than num_chs_used, as done mistakenly in
23042:599ceb5b0a9b) must be incremented before setting up an IRQ (and
decremented back when the setup failed). To avoid further confusion,
just eliminate the local variable altogether.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
--- a/xen/arch/x86/hpet.c
+++ b/xen/arch/x86/hpet.c
@@ -392,17 +392,17 @@ static int __init hpet_assign_irq(unsign
 return irq;
 }
 
-static unsigned int __init hpet_fsb_cap_lookup(void)
+static void __init hpet_fsb_cap_lookup(void)
 {
 u32 id;
- unsigned int i, num_chs, num_chs_used;
+ unsigned int i, num_chs;
 
 /* TODO. */
 if ( iommu_intremap )
 {
 printk(XENLOG_INFO "HPET's MSI mode hasn't been supported when "
 "Interrupt Remapping is enabled.\n");
- return 0;
+ return;
 }
 
 id = hpet_read32(HPET_ID);
@@ -412,13 +412,12 @@ static unsigned int __init hpet_fsb_cap_
 
 hpet_events = xmalloc_array(struct hpet_event_channel, num_chs);
 if ( !hpet_events )
- return 0;
+ return;
 memset(hpet_events, 0, num_chs * sizeof(*hpet_events));
 
- num_chs_used = 0;
 for ( i = 0; i < num_chs; i++ )
 {
- struct hpet_event_channel *ch = &hpet_events[num_chs_used];
+ struct hpet_event_channel *ch = &hpet_events[num_hpets_used];
 u32 cfg = hpet_read32(HPET_Tn_CFG(i));
 
 /* Only consider HPET timer with MSI support */
@@ -428,14 +427,12 @@ static unsigned int __init hpet_fsb_cap_
 ch->flags = 0;
 ch->idx = i;
 
- if ( (ch->irq = hpet_assign_irq(num_chs_used++)) < 0 )
- num_chs_used--;
+ if ( (ch->irq = hpet_assign_irq(num_hpets_used++)) < 0 )
+ num_hpets_used--;
 }
 
 printk(XENLOG_INFO "HPET: %u timers (%u will be used for broadcast)\n",
- num_chs, num_chs_used);
-
- return num_chs_used;
+ num_chs, num_hpets_used);
 }
 
 static struct hpet_event_channel *hpet_get_channel(unsigned int cpu)
@@ -555,7 +552,7 @@ void __init hpet_broadcast_init(void)
 
 cfg = hpet_read32(HPET_CFG);
 
- num_hpets_used = hpet_fsb_cap_lookup();
+ hpet_fsb_cap_lookup();
 if ( num_hpets_used > 0 )
 {
 /* Stop HPET legacy interrupts */

Attachment: x86-hpet-fix-23042.patch
Description: Text document

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