PCI/MSI: Add msi_setup_entry() to clean up MSI initialization

Move MSI entry stuff to a new function, msi_setup_entry(), to simplify
msi_capability_init() as MSI-X does.
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/msi.c

@@ -581,6 +581,38 @@ static int populate_msi_sysfs(struct pci_dev *pdev)
 	return ret;
 }
 
+static struct msi_desc *msi_setup_entry(struct pci_dev *dev)
+{
+	u16 control;
+	struct msi_desc *entry;
+
+	/* MSI Entry Initialization */
+	entry = alloc_msi_entry(dev);
+	if (!entry)
+		return NULL;
+
+	pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);
+
+	entry->msi_attrib.is_msix	= 0;
+	entry->msi_attrib.is_64		= !!(control & PCI_MSI_FLAGS_64BIT);
+	entry->msi_attrib.entry_nr	= 0;
+	entry->msi_attrib.maskbit	= !!(control & PCI_MSI_FLAGS_MASKBIT);
+	entry->msi_attrib.default_irq	= dev->irq;	/* Save IOAPIC IRQ */
+	entry->msi_attrib.pos		= dev->msi_cap;
+	entry->msi_attrib.multi_cap	= (control & PCI_MSI_FLAGS_QMASK) >> 1;
+
+	if (control & PCI_MSI_FLAGS_64BIT)
+		entry->mask_pos = dev->msi_cap + PCI_MSI_MASK_64;
+	else
+		entry->mask_pos = dev->msi_cap + PCI_MSI_MASK_32;
+
+	/* Save the initial mask status */
+	if (entry->msi_attrib.maskbit)
+		pci_read_config_dword(dev, entry->mask_pos, &entry->masked);
+
+	return entry;
+}
+
 /**
  * msi_capability_init - configure device's MSI capability structure
  * @dev: pointer to the pci_dev data structure of MSI device function
@@ -596,32 +628,15 @@ static int msi_capability_init(struct pci_dev *dev, int nvec)
 {
 	struct msi_desc *entry;
 	int ret;
-	u16 control;
 	unsigned mask;
 
 	msi_set_enable(dev, 0);	/* Disable MSI during set up */
 
-	pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, &control);
-	/* MSI Entry Initialization */
-	entry = alloc_msi_entry(dev);
+	entry = msi_setup_entry(dev);
 	if (!entry)
 		return -ENOMEM;
 
-	entry->msi_attrib.is_msix	= 0;
-	entry->msi_attrib.is_64		= !!(control & PCI_MSI_FLAGS_64BIT);
-	entry->msi_attrib.entry_nr	= 0;
-	entry->msi_attrib.maskbit	= !!(control & PCI_MSI_FLAGS_MASKBIT);
-	entry->msi_attrib.default_irq	= dev->irq;	/* Save IOAPIC IRQ */
-	entry->msi_attrib.pos		= dev->msi_cap;
-	entry->msi_attrib.multi_cap	= (control & PCI_MSI_FLAGS_QMASK) >> 1;
-
-	if (control & PCI_MSI_FLAGS_64BIT)
-		entry->mask_pos = dev->msi_cap + PCI_MSI_MASK_64;
-	else
-		entry->mask_pos = dev->msi_cap + PCI_MSI_MASK_32;
 	/* All MSIs are unmasked by default, Mask them all */
-	if (entry->msi_attrib.maskbit)
-		pci_read_config_dword(dev, entry->mask_pos, &entry->masked);
 	mask = msi_mask(entry->msi_attrib.multi_cap);
 	msi_mask_irq(entry, mask, mask);