[RFC PATCH 01/20] x86/xen/MSI: Eliminate arch_msix_mask_irq() and arch_msi_mask_irq()

[Yijing Wang <wangyijing@huawei.com>]

Commit 0e4ccb150 added two __weak arch functions arch_msix_mask_irq()
and arch_msi_mask_irq() to fix a bug found when running xen in x86.
Introduced these two funcntions make MSI code complex. This patch
reverted commit 0e4ccb150 and add #ifdef for x86 msi_chip to fix this
bug for simplicity. Also this is preparation for using struct
msi_chip instead of weak arch MSI functions in all platforms.

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 arch/x86/include/asm/x86_init.h |    3 ---
 arch/x86/kernel/apic/io_apic.c  |   15 +++++++++++++++
 arch/x86/kernel/x86_init.c      |   10 ----------
 arch/x86/pci/xen.c              |   13 +------------
 drivers/pci/msi.c               |   22 ++++++----------------
 include/linux/msi.h             |    2 --
 6 files changed, 22 insertions(+), 43 deletions(-)

diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index e45e4da..f58a9c7 100644
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -172,7 +172,6 @@ struct x86_platform_ops {
 
 struct pci_dev;
 struct msi_msg;
-struct msi_desc;
 
 struct x86_msi_ops {
 	int (*setup_msi_irqs)(struct pci_dev *dev, int nvec, int type);
@@ -183,8 +182,6 @@ struct x86_msi_ops {
 	void (*teardown_msi_irqs)(struct pci_dev *dev);
 	void (*restore_msi_irqs)(struct pci_dev *dev);
 	int  (*setup_hpet_msi)(unsigned int irq, unsigned int id);
-	u32 (*msi_mask_irq)(struct msi_desc *desc, u32 mask, u32 flag);
-	u32 (*msix_mask_irq)(struct msi_desc *desc, u32 flag);
 };
 
 struct IO_APIC_route_entry;
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 81e08ef..2609dcd 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -3019,14 +3019,29 @@ msi_set_affinity(struct irq_data *data, const struct cpumask *mask, bool force)
 	return IRQ_SET_MASK_OK_NOCOPY;
 }
 
+#ifdef CONFIG_XEN
+static void nop_unmask_msi_irq(struct irq_data *data)
+{
+}
+
+static void nop_mask_msi_irq(struct irq_data *data)
+{
+}
+#endif
+
 /*
  * IRQ Chip for MSI PCI/PCI-X/PCI-Express Devices,
  * which implement the MSI or MSI-X Capability Structure.
  */
 static struct irq_chip msi_chip = {
 	.name			= "PCI-MSI",
+#ifdef CONFIG_XEN
+	.irq_unmask		= nop_unmask_msi_irq,
+	.irq_mask		= nop_mask_msi_irq,
+#else
 	.irq_unmask		= unmask_msi_irq,
 	.irq_mask		= mask_msi_irq,
+#endif
 	.irq_ack		= ack_apic_edge,
 	.irq_set_affinity	= msi_set_affinity,
 	.irq_retrigger		= ioapic_retrigger_irq,
diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
index e48b674..234b072 100644
--- a/arch/x86/kernel/x86_init.c
+++ b/arch/x86/kernel/x86_init.c
@@ -116,8 +116,6 @@ struct x86_msi_ops x86_msi = {
 	.teardown_msi_irqs	= default_teardown_msi_irqs,
 	.restore_msi_irqs	= default_restore_msi_irqs,
 	.setup_hpet_msi		= default_setup_hpet_msi,
-	.msi_mask_irq		= default_msi_mask_irq,
-	.msix_mask_irq		= default_msix_mask_irq,
 };
 
 /* MSI arch specific hooks */
@@ -140,14 +138,6 @@ void arch_restore_msi_irqs(struct pci_dev *dev)
 {
 	x86_msi.restore_msi_irqs(dev);
 }
-u32 arch_msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
-{
-	return x86_msi.msi_mask_irq(desc, mask, flag);
-}
-u32 arch_msix_mask_irq(struct msi_desc *desc, u32 flag)
-{
-	return x86_msi.msix_mask_irq(desc, flag);
-}
 #endif
 
 struct x86_io_apic_ops x86_io_apic_ops = {
diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index 905956f..55c7858 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -393,14 +393,7 @@ static void xen_teardown_msi_irq(unsigned int irq)
 {
 	xen_destroy_irq(irq);
 }
-static u32 xen_nop_msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
-{
-	return 0;
-}
-static u32 xen_nop_msix_mask_irq(struct msi_desc *desc, u32 flag)
-{
-	return 0;
-}
+
 #endif
 
 int __init pci_xen_init(void)
@@ -424,8 +417,6 @@ int __init pci_xen_init(void)
 	x86_msi.setup_msi_irqs = xen_setup_msi_irqs;
 	x86_msi.teardown_msi_irq = xen_teardown_msi_irq;
 	x86_msi.teardown_msi_irqs = xen_teardown_msi_irqs;
-	x86_msi.msi_mask_irq = xen_nop_msi_mask_irq;
-	x86_msi.msix_mask_irq = xen_nop_msix_mask_irq;
 #endif
 	return 0;
 }
@@ -505,8 +496,6 @@ int __init pci_xen_initial_domain(void)
 	x86_msi.setup_msi_irqs = xen_initdom_setup_msi_irqs;
 	x86_msi.teardown_msi_irq = xen_teardown_msi_irq;
 	x86_msi.restore_msi_irqs = xen_initdom_restore_msi_irqs;
-	x86_msi.msi_mask_irq = xen_nop_msi_mask_irq;
-	x86_msi.msix_mask_irq = xen_nop_msix_mask_irq;
 #endif
 	xen_setup_acpi_sci();
 	__acpi_register_gsi = acpi_register_gsi_xen;
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 5a40516..bff25df 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -173,7 +173,7 @@ static inline __attribute_const__ u32 msi_mask(unsigned x)
  * reliably as devices without an INTx disable bit will then generate a
  * level IRQ which will never be cleared.
  */
-u32 default_msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
+static u32 __msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
 {
 	u32 mask_bits = desc->masked;
 
@@ -187,14 +187,9 @@ u32 default_msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
 	return mask_bits;
 }
 
-__weak u32 arch_msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
-{
-	return default_msi_mask_irq(desc, mask, flag);
-}
-
 static void msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
 {
-	desc->masked = arch_msi_mask_irq(desc, mask, flag);
+	desc->masked = __msi_mask_irq(desc, mask, flag);
 }
 
 /*
@@ -204,7 +199,7 @@ static void msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
  * file.  This saves a few milliseconds when initialising devices with lots
  * of MSI-X interrupts.
  */
-u32 default_msix_mask_irq(struct msi_desc *desc, u32 flag)
+static u32 __msix_mask_irq(struct msi_desc *desc, u32 flag)
 {
 	u32 mask_bits = desc->masked;
 	unsigned offset = desc->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE +
@@ -217,14 +212,9 @@ u32 default_msix_mask_irq(struct msi_desc *desc, u32 flag)
 	return mask_bits;
 }
 
-__weak u32 arch_msix_mask_irq(struct msi_desc *desc, u32 flag)
-{
-	return default_msix_mask_irq(desc, flag);
-}
-
 static void msix_mask_irq(struct msi_desc *desc, u32 flag)
 {
-	desc->masked = arch_msix_mask_irq(desc, flag);
+	desc->masked = __msix_mask_irq(desc, flag);
 }
 
 static void msi_set_mask_bit(struct irq_data *data, u32 flag)
@@ -893,7 +883,7 @@ void pci_msi_shutdown(struct pci_dev *dev)
 	/* Return the device with MSI unmasked as initial states */
 	mask = msi_mask(desc->msi_attrib.multi_cap);
 	/* Keep cached state to be restored */
-	arch_msi_mask_irq(desc, mask, ~mask);
+	__msi_mask_irq(desc, mask, ~mask);
 
 	/* Restore dev->irq to its default pin-assertion irq */
 	dev->irq = desc->msi_attrib.default_irq;
@@ -993,7 +983,7 @@ void pci_msix_shutdown(struct pci_dev *dev)
 	/* Return the device with MSI-X masked as initial states */
 	list_for_each_entry(entry, &dev->msi_list, list) {
 		/* Keep cached states to be restored */
-		arch_msix_mask_irq(entry, 1);
+		__msix_mask_irq(entry, 1);
 	}
 
 	msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_ENABLE, 0);
diff --git a/include/linux/msi.h b/include/linux/msi.h
index 8103f32..78e6b6e 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -65,8 +65,6 @@ void arch_restore_msi_irqs(struct pci_dev *dev);
 
 void default_teardown_msi_irqs(struct pci_dev *dev);
 void default_restore_msi_irqs(struct pci_dev *dev);
-u32 default_msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag);
-u32 default_msix_mask_irq(struct msi_desc *desc, u32 flag);
 
 struct msi_chip {
 	struct module *owner;
-- 
1.7.1