PCI: Fix return value from pci_user_{read,write}_config_*()

The PCI user-space config accessors pci_user_{read,write}_config_*() return
negative error numbers, which were introduced by commit 34e3207
("PCI: handle positive error codes").  That patch converted all positive
error numbers from platform-specific PCI config accessors to -EINVAL, which
means the callers don't know anything about the specific cause of the
failure.

The patch fixes the issue by converting the positive PCIBIOS_* error values
to generic negative error numbers with pcibios_err_to_errno().

[bhelgaas: changelog]
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Greg Thelen <gthelen@google.com>

drivers/pci/access.c

@@ -148,7 +148,7 @@ static noinline void pci_wait_cfg(struct pci_dev *dev)
 int pci_user_read_config_##size						\
 	(struct pci_dev *dev, int pos, type *val)			\
 {									\
-	int ret = 0;							\
+	int ret = PCIBIOS_SUCCESSFUL;					\
 	u32 data = -1;							\
 	if (PCI_##size##_BAD)						\
 		return -EINVAL;						\
@@ -159,9 +159,7 @@ int pci_user_read_config_##size						\
 					pos, sizeof(type), &data);	\
 	raw_spin_unlock_irq(&pci_lock);				\
 	*val = (type)data;						\
-	if (ret > 0)							\
-		ret = -EINVAL;						\
-	return ret;							\
+	return pcibios_err_to_errno(ret);				\
 }									\
 EXPORT_SYMBOL_GPL(pci_user_read_config_##size);
 
@@ -170,7 +168,7 @@ EXPORT_SYMBOL_GPL(pci_user_read_config_##size);
 int pci_user_write_config_##size					\
 	(struct pci_dev *dev, int pos, type val)			\
 {									\
-	int ret = -EIO;							\
+	int ret = PCIBIOS_SUCCESSFUL;					\
 	if (PCI_##size##_BAD)						\
 		return -EINVAL;						\
 	raw_spin_lock_irq(&pci_lock);				\
@@ -179,9 +177,7 @@ int pci_user_write_config_##size					\
 	ret = dev->bus->ops->write(dev->bus, dev->devfn,		\
 					pos, sizeof(type), val);	\
 	raw_spin_unlock_irq(&pci_lock);				\
-	if (ret > 0)							\
-		ret = -EINVAL;						\
-	return ret;							\
+	return pcibios_err_to_errno(ret);				\
 }									\
 EXPORT_SYMBOL_GPL(pci_user_write_config_##size);
 

include/linux/pci.h

@@ -518,7 +518,7 @@ static inline int pcibios_err_to_errno(int err)
 	case PCIBIOS_FUNC_NOT_SUPPORTED:
 		return -ENOENT;
 	case PCIBIOS_BAD_VENDOR_ID:
-		return -EINVAL;
+		return -ENOTTY;
 	case PCIBIOS_DEVICE_NOT_FOUND:
 		return -ENODEV;
 	case PCIBIOS_BAD_REGISTER_NUMBER:
@@ -529,7 +529,7 @@ static inline int pcibios_err_to_errno(int err)
 		return -ENOSPC;
 	}
 
-	return -ENOTTY;
+	return -ERANGE;
 }
 
 /* Low-level architecture-dependent routines */