> On 01/14, Lorenzo Bianconi wrote:
> > From: Marek Majtyka <alardam@xxxxxxxxx>
>
[...]
>
> Maybe stupid question: why do we need WRITE_ONCE here?
> And if we do need it, do we need READ_ONCE as well?
>
> WRITE_ONCE(*xdp_features, READ_ONCE(*xdp_features) | flags);
This part is from the Marek's original series. I will let him to comment on it.
>
> ?
>
> Also, would it make sense to drop this __xdp_features_set_redirect_target
> and just define the following:
>
> static inline void
> xdp_features_set_redirect_target(xdp_features_t *xdp_features, bool
> support_sg)
> {
> xdp_features_t flags = NETDEV_XDP_ACT_NDO_XMIT;
>
> if (support_sg)
> flags |= NETDEV_XDP_ACT_NDO_XMIT_SG;
> *xdp_features |= flags; /* or WRITE_ONCE */
> }
>
> This should avoid having two different sets of functions. Or does it
> look worse because of that 'naked' true/false argument in the call
> sites?
I did this way because we will mainly run it with support_sg set to false,
but I do not have a strong opinion on it, I am fine both ways. I will fix it.
Regards,
Lorenzo
>
>
> > +}
> > +
> > +static inline void
> > +xdp_features_clear_redirect_target(xdp_features_t *xdp_features)
> > +{
> > + WRITE_ONCE(*xdp_features,
> > + *xdp_features & ~(NETDEV_XDP_ACT_NDO_XMIT |
> > + NETDEV_XDP_ACT_NDO_XMIT_SG));
> > +}
> > +
> > +#else
> > +
> > +static inline void
> > +__xdp_features_set_redirect_target(xdp_features_t *xdp_features, u32
> > flags)
> > +{
> > +}
> > +
> > +static inline void
> > +xdp_features_clear_redirect_target(xdp_features_t *xdp_features)
> > +{
> > +}
> > +
> > +#endif
> > +
> > +static inline void
> > +xdp_features_set_redirect_target(xdp_features_t *xdp_features)
> > +{
> > + __xdp_features_set_redirect_target(xdp_features,
> > + NETDEV_XDP_ACT_NDO_XMIT |
> > + NETDEV_XDP_ACT_NDO_XMIT_SG);
> > +}
> > +
> > #define DEV_MAP_BULK_SIZE XDP_BULK_QUEUE_SIZE
>
> > #endif /* __LINUX_NET_XDP_H__ */
> > --
> > 2.39.0
>
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