PCI: remove redundant capabilities checking in pci_{save, restore}_pcie_state

Unlike PCI Express v1's Capabilities Structure, v2's requires the entire
structure to be implemented.  In v2 structures, register fields that
are not implemented are present but hardwired to 0x0.  These may
include: Link Capabilities, Status, and Control; Slot Capabilities,
Status, and Control; Root Capabilities, Status, and Control; and all of
the '2' (Device, Link, and Slot) Capabilities, Status, and Control
registers.

This patch removes the redundant capability checks corresponding to the
Link 2's and Slot 2's, Capabilities, Status, and Control registers as they
will be present if Device Capabilities 2's registers are (which explains
why the macros for each of the three are identical).

Signed-off-by: Myron Stowe <myron.stowe@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/pci.c

@@ -854,12 +854,6 @@ EXPORT_SYMBOL(pci_choose_state);
 		((flags & PCI_EXP_FLAGS_VERS) > 1 ||	\
 		 (type == PCI_EXP_TYPE_ROOT_PORT ||	\
 		  type == PCI_EXP_TYPE_RC_EC))
-#define pcie_cap_has_devctl2(type, flags)		\
-		((flags & PCI_EXP_FLAGS_VERS) > 1)
-#define pcie_cap_has_lnkctl2(type, flags)		\
-		((flags & PCI_EXP_FLAGS_VERS) > 1)
-#define pcie_cap_has_sltctl2(type, flags)		\
-		((flags & PCI_EXP_FLAGS_VERS) > 1)
 
 static struct pci_cap_saved_state *pci_find_saved_cap(
 	struct pci_dev *pci_dev, char cap)
@@ -902,13 +896,14 @@ static int pci_save_pcie_state(struct pci_dev *dev)
 		pci_read_config_word(dev, pos + PCI_EXP_SLTCTL, &cap[i++]);
 	if (pcie_cap_has_rtctl(dev->pcie_type, flags))
 		pci_read_config_word(dev, pos + PCI_EXP_RTCTL, &cap[i++]);
-	if (pcie_cap_has_devctl2(dev->pcie_type, flags))
-		pci_read_config_word(dev, pos + PCI_EXP_DEVCTL2, &cap[i++]);
-	if (pcie_cap_has_lnkctl2(dev->pcie_type, flags))
-		pci_read_config_word(dev, pos + PCI_EXP_LNKCTL2, &cap[i++]);
-	if (pcie_cap_has_sltctl2(dev->pcie_type, flags))
-		pci_read_config_word(dev, pos + PCI_EXP_SLTCTL2, &cap[i++]);
 
+	pos = pci_pcie_cap2(dev);
+	if (!pos)
+		return 0;
+
+	pci_read_config_word(dev, pos + PCI_EXP_DEVCTL2, &cap[i++]);
+	pci_read_config_word(dev, pos + PCI_EXP_LNKCTL2, &cap[i++]);
+	pci_read_config_word(dev, pos + PCI_EXP_SLTCTL2, &cap[i++]);
 	return 0;
 }
 
@@ -935,12 +930,14 @@ static void pci_restore_pcie_state(struct pci_dev *dev)
 		pci_write_config_word(dev, pos + PCI_EXP_SLTCTL, cap[i++]);
 	if (pcie_cap_has_rtctl(dev->pcie_type, flags))
 		pci_write_config_word(dev, pos + PCI_EXP_RTCTL, cap[i++]);
-	if (pcie_cap_has_devctl2(dev->pcie_type, flags))
-		pci_write_config_word(dev, pos + PCI_EXP_DEVCTL2, cap[i++]);
-	if (pcie_cap_has_lnkctl2(dev->pcie_type, flags))
-		pci_write_config_word(dev, pos + PCI_EXP_LNKCTL2, cap[i++]);
-	if (pcie_cap_has_sltctl2(dev->pcie_type, flags))
-		pci_write_config_word(dev, pos + PCI_EXP_SLTCTL2, cap[i++]);
+
+	pos = pci_pcie_cap2(dev);
+	if (!pos)
+		return;
+
+	pci_write_config_word(dev, pos + PCI_EXP_DEVCTL2, cap[i++]);
+	pci_write_config_word(dev, pos + PCI_EXP_LNKCTL2, cap[i++]);
+	pci_write_config_word(dev, pos + PCI_EXP_SLTCTL2, cap[i++]);
 }