Re: [PATCH v5 1/3] ethdev: new API to free consumed buffers in Tx ring

[Billy McFall <bmcfall@redhat.com>]

On Tue, Mar 7, 2017 at 11:03 AM, Thomas Monjalon <thomas.monjalon@6wind.com>
wrote:

> 2017-03-07 09:29, Billy McFall:
> > On Mon, Feb 27, 2017 at 8:48 AM, Thomas Monjalon <
> thomas.monjalon@6wind.com>
> > wrote:
> > > I think you could use rte_errno (while keeping negative return codes).
> > >
> >
> > I can do that if you want, but if I understand your comment, it will make
> > the implementation of the function not as clean. I cannot use the
> existing
> > RTE_ETH_VALID_PORTID_OR_ERR_RET(..) and RTE_FUNC_PTR_OR_ERR_RET(..)
> MACROs
> > because they are handling the return on error. Or am I missing something?
>
> Yes. Maybe we need new macros for basic error management with rte_errno.
>
> Looking at the code. Do you think we need new MACROs or just set rte_errno
in the existing? What would be the down side to setting rte_errno for all
the existing calls?

Looks like RTE_ETH_VALID_PORTID_OR_ERR_RET(..) is being called ~135 times.
Most calls are with retval set to either -ENODEV or -EINVAL. A few
instances of 0 and -1, but not many.

Looks like RTE_FUNC_PTR_OR_ERR_RET(..) is being called ~100 times. Most
calls are with retval set to -ENOTSUP. A few instances of 0, but not many.

I was thinking:
/* Macros to check for valid port */
#define RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, retval) do { \
if (!rte_eth_dev_is_valid_port(port_id)) { \
RTE_PMD_DEBUG_TRACE("Invalid port_id=%d\n", port_id); \
+ if (retval < 0) \
+ rte_errno = -retval; \
return retval; \
} \
} while (0)

Thanks,
Billy