[PATCH v5 33/33] x86, ioapic: Hotadd of IOAPICs described in static MADT

[Yinghai Lu]

From: Rui Wang <rui.y.wang@xxxxxxxxx>

For IOAPICs described in static MADT, we already called __mp_register_ioapic()
in arch_early_irq_init(). During boot PCI root hotadd will call it again and
will find it already registered, thus register_ioapic() won't add it to the
ioapic_list. Subsequent hot-removal will also fail because it is not
found on the ioapic_list.

Signed-off-by: Rui Wang <rui.y.wang@xxxxxxxxx>
Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
---
 arch/x86/kernel/apic/io_apic.c | 4 +++-
 drivers/pci/ioapic.c           | 3 ++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 248a21d..ad28933 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -3964,8 +3964,10 @@ int __mp_register_ioapic(int id, u32 address, u32 gsi_base, bool hotadd)
 
 	/* already registered ? */
 	idx = __mp_find_ioapic(gsi_base);
-	if (idx >= 0)
+	if (idx >= 0) {
+		ret = -EEXIST;
 		goto out;
+	}
 
 	idx = find_first_zero_bit(ioapics_mask, MAX_IO_APICS);
 	if (idx >= MAX_IO_APICS) {
diff --git a/drivers/pci/ioapic.c b/drivers/pci/ioapic.c
index 54de155..0a23295 100644
--- a/drivers/pci/ioapic.c
+++ b/drivers/pci/ioapic.c
@@ -126,7 +126,8 @@ static void handle_ioapic_add(acpi_handle handle, struct pci_dev **pdev,
 		}
 	}
 
-	if (acpi_register_ioapic(handle, res->start, gsi_base)) {
+	ret = acpi_register_ioapic(handle, res->start, gsi_base);
+	if (ret && ret != -EEXIST) {
 		if (dev)
 			goto exit_release;
 		return;
-- 
1.8.4

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