Re: [dpdk-dev] [PATCH v6 1/2] bus/pci: harmonize and document rte_pci_read_config return value

[Luca Boccassi <bluca@debian.org>]

On Tue, 2018-08-28 at 11:12 +0100, Luca Boccassi wrote:
> On Linux, rte_pci_read_config on success returns the number of read
> bytes, but on BSD it returns 0.
> Document the return values, and have BSD behave as Linux does.
> 
> At least one case (bnx2x PMD) treats 0 as an error, so the change
> makes sense also for that.
> 
> Signed-off-by: Luca Boccassi <bluca@debian.org>
> ---
>  drivers/bus/pci/bsd/pci.c     | 4 +++-
>  drivers/bus/pci/rte_bus_pci.h | 2 ++
>  2 files changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/bus/pci/bsd/pci.c b/drivers/bus/pci/bsd/pci.c
> index 655b34b7e4..175d83cf1b 100644
> --- a/drivers/bus/pci/bsd/pci.c
> +++ b/drivers/bus/pci/bsd/pci.c
> @@ -439,6 +439,8 @@ int rte_pci_read_config(const struct
> rte_pci_device *dev,
>  {
>  	int fd = -1;
>  	int size;
> +	/* Copy Linux implementation's behaviour */
> +	const int return_len = len;
>  	struct pci_io pi = {
>  		.pi_sel = {
>  			.pc_domain = dev->addr.domain,
> @@ -469,7 +471,7 @@ int rte_pci_read_config(const struct
> rte_pci_device *dev,
>  	}
>  	close(fd);
>  
> -	return 0;
> +	return return_len;
>  
>   error:
>  	if (fd >= 0)
> diff --git a/drivers/bus/pci/rte_bus_pci.h
> b/drivers/bus/pci/rte_bus_pci.h
> index 0d1955ffe0..df8f64798d 100644
> --- a/drivers/bus/pci/rte_bus_pci.h
> +++ b/drivers/bus/pci/rte_bus_pci.h
> @@ -219,6 +219,8 @@ void rte_pci_unregister(struct rte_pci_driver
> *driver);
>   *   The length of the data buffer.
>   * @param offset
>   *   The offset into PCI config space
> + * @return
> + *  Number of bytes read on success, negative on error.
>   */
>  int rte_pci_read_config(const struct rte_pci_device *device,
>  		void *buf, size_t len, off_t offset);

Hi Bruce,

Any chance you could please review the small BSD patch above when you
have a sec? Thanks!

-- 
Kind regards,
Luca Boccassi