[PATCH] PCI: Make error code types consistent in pci_{read,write}_config_*

[Brian Norris <briannorris@chromium.org>]

Callers normally treat the config space accessors as returning PCBIOS_*
error codes, not Linux error codes (or they don't look at them at all).
We have pcibios_err_to_errno(), in case the error code needs translated.

Fixes: 4b1038834739 ("PCI: Don't attempt config access to disconnected devices")
Signed-off-by: Brian Norris <briannorris@chromium.org>
---
+ others, change subject

On Tue, May 23, 2017 at 11:44:01AM -0700, Brian Norris wrote:
> But the high level code doesn't handle this
> consistently. See, e.g., pci_read_config_byte() which can return regular
> Linux error codes (like -ENODEV), except it also passes up the return
> code of pci_read_config_byte() (a PCIBIOS_* code) directly.

Apparently this is new (inconsistent) behavior in 4.12-rc1. Seems like
an oversight to me.

> So callers don't really know whether to treat the value from
> pci_read_config_<foo>() as a PCIBIOS_* code (which should be translated
> with pcibios_err_to_errno()) or as a standard Linux errno.
> 
> But then, there are relatively few callers (less than 10% of
> pci_read_config_<foo>(); even fewer for writes) that actually check the
> error codes...
> 
> Maybe the "fix" is to replace -ENODEV with PCIBIOS_DEVICE_NOT_FOUND for
> the inconsistent cases (pci_{read,write}_config_{byte,word,dword}()).

Fix implemented in the surrounding patch.

 drivers/pci/access.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/access.c b/drivers/pci/access.c
index 74cf5fffb1e1..c80e37a69305 100644
--- a/drivers/pci/access.c
+++ b/drivers/pci/access.c
@@ -896,7 +896,7 @@ int pci_read_config_byte(const struct pci_dev *dev, int where, u8 *val)
 {
 	if (pci_dev_is_disconnected(dev)) {
 		*val = ~0;
-		return -ENODEV;
+		return PCIBIOS_DEVICE_NOT_FOUND;
 	}
 	return pci_bus_read_config_byte(dev->bus, dev->devfn, where, val);
 }
@@ -906,7 +906,7 @@ int pci_read_config_word(const struct pci_dev *dev, int where, u16 *val)
 {
 	if (pci_dev_is_disconnected(dev)) {
 		*val = ~0;
-		return -ENODEV;
+		return PCIBIOS_DEVICE_NOT_FOUND;
 	}
 	return pci_bus_read_config_word(dev->bus, dev->devfn, where, val);
 }
@@ -917,7 +917,7 @@ int pci_read_config_dword(const struct pci_dev *dev, int where,
 {
 	if (pci_dev_is_disconnected(dev)) {
 		*val = ~0;
-		return -ENODEV;
+		return PCIBIOS_DEVICE_NOT_FOUND;
 	}
 	return pci_bus_read_config_dword(dev->bus, dev->devfn, where, val);
 }
@@ -926,7 +926,7 @@ EXPORT_SYMBOL(pci_read_config_dword);
 int pci_write_config_byte(const struct pci_dev *dev, int where, u8 val)
 {
 	if (pci_dev_is_disconnected(dev))
-		return -ENODEV;
+		return PCIBIOS_DEVICE_NOT_FOUND;
 	return pci_bus_write_config_byte(dev->bus, dev->devfn, where, val);
 }
 EXPORT_SYMBOL(pci_write_config_byte);
@@ -934,7 +934,7 @@ EXPORT_SYMBOL(pci_write_config_byte);
 int pci_write_config_word(const struct pci_dev *dev, int where, u16 val)
 {
 	if (pci_dev_is_disconnected(dev))
-		return -ENODEV;
+		return PCIBIOS_DEVICE_NOT_FOUND;
 	return pci_bus_write_config_word(dev->bus, dev->devfn, where, val);
 }
 EXPORT_SYMBOL(pci_write_config_word);
@@ -943,7 +943,7 @@ int pci_write_config_dword(const struct pci_dev *dev, int where,
 					 u32 val)
 {
 	if (pci_dev_is_disconnected(dev))
-		return -ENODEV;
+		return PCIBIOS_DEVICE_NOT_FOUND;
 	return pci_bus_write_config_dword(dev->bus, dev->devfn, where, val);
 }
 EXPORT_SYMBOL(pci_write_config_dword);
-- 
2.13.0.219.gdb65acc882-goog