1 files changed, 27 insertions, 16 deletions

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 913d4bd2913a..85050c9ab755 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -394,13 +394,21 @@ union entry_union {
         struct IO_APIC_route_entry entry;
 };
 
+static struct IO_APIC_route_entry __ioapic_read_entry(int apic, int pin)
+{
+        union entry_union eu;
+
+        eu.w1 = io_apic_read(apic, 0x10 + 2 * pin);
+        eu.w2 = io_apic_read(apic, 0x11 + 2 * pin);
+        return eu.entry;
+}
+
 static struct IO_APIC_route_entry ioapic_read_entry(int apic, int pin)
 {
         union entry_union eu;
         unsigned long flags;
         raw_spin_lock_irqsave(&ioapic_lock, flags);
-        eu.w1 = io_apic_read(apic, 0x10 + 2 * pin);
-        eu.w2 = io_apic_read(apic, 0x11 + 2 * pin);
+        eu.entry = __ioapic_read_entry(apic, pin);
         raw_spin_unlock_irqrestore(&ioapic_lock, flags);
         return eu.entry;
 }
@@ -529,18 +537,6 @@ static void io_apic_modify_irq(struct irq_cfg *cfg,
                 __io_apic_modify_irq(entry, mask_and, mask_or, final);
 }
 
-static void __mask_and_edge_IO_APIC_irq(struct irq_pin_list *entry)
-{
-        __io_apic_modify_irq(entry, ~IO_APIC_REDIR_LEVEL_TRIGGER,
-                             IO_APIC_REDIR_MASKED, NULL);
-}
-
-static void __unmask_and_level_IO_APIC_irq(struct irq_pin_list *entry)
-{
-        __io_apic_modify_irq(entry, ~IO_APIC_REDIR_MASKED,
-                             IO_APIC_REDIR_LEVEL_TRIGGER, NULL);
-}
-
 static void io_apic_sync(struct irq_pin_list *entry)
 {
         /*
@@ -2496,8 +2492,23 @@ static void eoi_ioapic_irq(unsigned int irq, struct irq_cfg *cfg)
                         else
                                 io_apic_eoi(entry->apic, cfg->vector);
                 } else {
-                        __mask_and_edge_IO_APIC_irq(entry);
-                        __unmask_and_level_IO_APIC_irq(entry);
+                        struct IO_APIC_route_entry rte, rte1;
+
+                        rte = rte1 =
+                                __ioapic_read_entry(entry->apic, entry->pin);
+
+                        /*
+                         * Mask the entry and change the trigger mode to edge.
+                         */
+                        rte1.mask = 1;
+                        rte1.trigger = IOAPIC_EDGE;
+
+                        __ioapic_write_entry(apic, pin, rte1);
+
+                        /*
+                         * Restore the previous level triggered entry.
+                         */
+                        __ioapic_write_entry(apic, pin, rte);
                 }
         }
         raw_spin_unlock_irqrestore(&ioapic_lock, flags);