[v2] PCI: Fix return value from pci_user_{read,write}_config_*()

PCI accessors from user space pci_user_{read,write}_config_*()
return negative error number, which was introduced by commit
34e32072 ("PCI: handle positive error codes"). That patch coverts
all positive error numbers from platform specific PCI config
accessors to -EINVAL. The upper layer calling to those PCI config
accessors hardly know the specific cause from the return value
when hitting failures.

The patch fixes the issue by doing the conversion (from positive
to negative) using existing function pcibios_err_to_errno().

v2: pcibios_err_to_errno() translates unrecognized value to -ERANGE.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
---
 drivers/pci/access.c | 12 ++++--------
 include/linux/pci.h  |  4 ++--
 2 files changed, 6 insertions(+), 10 deletions(-)

On Tue, May 20 2014, Gavin Shan <gwshan@linux.vnet.ibm.com> wrote:

> PCI accessors from user space pci_user_{read,write}_config_*()
> return negative error number, which was introduced by commit
> 34e32072 ("PCI: handle positive error codes"). That patch coverts
> all positive error numbers from platform specific PCI config
> accessors to -EINVAL. The upper layer calling to those PCI config
> accessors hardly know the specific cause from the return value
> when hitting failures.
>
> The patch fixes the issue by doing the conversion (from positive
> to negative) using existing function pcibios_err_to_errno().
>
> v2: pcibios_err_to_errno() translates unrecognized value to -ERANGE.
>
> Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>

Acked-by: Greg Thelen <gthelen@google.com>
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On Wed, May 21, 2014 at 03:23:30PM +1000, Gavin Shan wrote:
> PCI accessors from user space pci_user_{read,write}_config_*()
> return negative error number, which was introduced by commit
> 34e32072 ("PCI: handle positive error codes"). That patch coverts
> all positive error numbers from platform specific PCI config
> accessors to -EINVAL. The upper layer calling to those PCI config
> accessors hardly know the specific cause from the return value
> when hitting failures.
> 
> The patch fixes the issue by doing the conversion (from positive
> to negative) using existing function pcibios_err_to_errno().
> 
> v2: pcibios_err_to_errno() translates unrecognized value to -ERANGE.
> 
> Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>

Applied with Greg's ack to pci/misc for v3.16, thanks!

> ---
>  drivers/pci/access.c | 12 ++++--------
>  include/linux/pci.h  |  4 ++--
>  2 files changed, 6 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/pci/access.c b/drivers/pci/access.c
> index 7f8b78c..8c148f3 100644
> --- a/drivers/pci/access.c
> +++ b/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);
>  
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index aab57b4..ece7bef 100644
> --- a/include/linux/pci.h
> +++ b/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 */
> -- 
> 1.8.3.2
> 
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