On 2026-03-10 at 16:17:36, Björn Töpel ([email protected]) wrote: > Extend struct ethtool_ops with three loopback callbacks that drivers > can implement for MAC-level loopback control: > > - get_loopback(dev, name, id, entry): exact lookup by name and > instance id, used by doit (single-entry GET) requests. > > - get_loopback_by_index(dev, index, entry): flat enumeration by > index, used by dumpit (multi-entry GET) requests to iterate all > loopback points on a device. > > - set_loopback(dev, entry, extack): apply a loopback configuration > change. Returns 1 if hardware state changed, 0 if no-op. > > Wire the MAC component into loopback.c's dispatch functions. For dump > enumeration, MAC entries are tried first via the driver's > get_loopback_by_index() op, then MODULE/CMIS entries follow at the > next index offset. > > Signed-off-by: Björn Töpel <[email protected]> > --- > include/linux/ethtool.h | 7 ++++++ > net/ethtool/loopback.c | 56 ++++++++++++++++++++++++++++++++--------- > 2 files changed, 51 insertions(+), 12 deletions(-) >
The MAC loopback callbacks look good. Reviewed-by: Naveen Mamindlapalli <[email protected]> > diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h > index c9beca11fc40..8893e732f930 100644 > --- a/include/linux/ethtool.h > +++ b/include/linux/ethtool.h > @@ -1321,6 +1321,13 @@ struct ethtool_ops { > int (*set_mm)(struct net_device *dev, struct ethtool_mm_cfg *cfg, > struct netlink_ext_ack *extack); > void (*get_mm_stats)(struct net_device *dev, struct ethtool_mm_stats > *stats); > + int (*get_loopback)(struct net_device *dev, const char *name, > + u32 id, struct ethtool_loopback_entry *entry); > + int (*get_loopback_by_index)(struct net_device *dev, u32 index, > + struct ethtool_loopback_entry *entry); > + int (*set_loopback)(struct net_device *dev, > + const struct ethtool_loopback_entry *entry, > + struct netlink_ext_ack *extack); > }; > > int ethtool_check_ops(const struct ethtool_ops *ops); > diff --git a/net/ethtool/loopback.c b/net/ethtool/loopback.c > index ed184f45322e..9c5834be743f 100644 > --- a/net/ethtool/loopback.c > +++ b/net/ethtool/loopback.c > @@ -86,6 +86,10 @@ static int loopback_get(struct net_device *dev, > struct ethtool_loopback_entry *entry) > { > switch (component) { > + case ETHTOOL_LOOPBACK_COMPONENT_MAC: > + if (!dev->ethtool_ops->get_loopback) > + return -EOPNOTSUPP; > + return dev->ethtool_ops->get_loopback(dev, name, id, entry); > case ETHTOOL_LOOPBACK_COMPONENT_MODULE: > return ethtool_cmis_get_loopback(dev, name, entry); > default: > @@ -93,10 +97,22 @@ static int loopback_get(struct net_device *dev, > } > } > > -static int loopback_get_by_index(struct net_device *dev, u32 index, > +static int loopback_get_by_index(struct net_device *dev, > + enum ethtool_loopback_component component, > + u32 index, > struct ethtool_loopback_entry *entry) > { > - return ethtool_cmis_get_loopback_by_index(dev, index, entry); > + switch (component) { > + case ETHTOOL_LOOPBACK_COMPONENT_MAC: > + if (!dev->ethtool_ops->get_loopback_by_index) > + return -EOPNOTSUPP; > + return dev->ethtool_ops->get_loopback_by_index(dev, index, > + entry); > + case ETHTOOL_LOOPBACK_COMPONENT_MODULE: > + return ethtool_cmis_get_loopback_by_index(dev, index, entry); > + default: > + return -EOPNOTSUPP; > + } > } > > static int loopback_prepare_data(const struct ethnl_req_info *req_base, > @@ -116,7 +132,8 @@ static int loopback_prepare_data(const struct > ethnl_req_info *req_base, > ret = loopback_get(dev, req_info->component, req_info->id, > req_info->name, &data->entry); > else > - ret = loopback_get_by_index(dev, req_info->index, &data->entry); > + ret = loopback_get_by_index(dev, req_info->component, > + req_info->index, &data->entry); > > ethnl_ops_complete(dev); > > @@ -225,6 +242,10 @@ static int __loopback_set(struct net_device *dev, > struct netlink_ext_ack *extack) > { > switch (entry->component) { > + case ETHTOOL_LOOPBACK_COMPONENT_MAC: > + if (!dev->ethtool_ops->set_loopback) > + return -EOPNOTSUPP; > + return dev->ethtool_ops->set_loopback(dev, entry, extack); > case ETHTOOL_LOOPBACK_COMPONENT_MODULE: > return ethtool_cmis_set_loopback(dev, entry, extack); > default: > @@ -274,20 +295,31 @@ static int loopback_dump_one_dev(struct sk_buff *skb, > { > struct loopback_req_info *req_info = > container_of(ctx->req_info, struct loopback_req_info, base); > + /* pos_sub encodes: upper 16 bits = component phase, lower 16 = index > + * within that component. dump_one_dev is called repeatedly with > + * increasing pos_sub until all components are exhausted. > + */ > + enum ethtool_loopback_component phase = *pos_sub >> 16; > + u32 idx = *pos_sub & 0xffff; > int ret; > > - for (;; (*pos_sub)++) { > - req_info->index = *pos_sub; > - ret = ethnl_default_dump_one(skb, ctx->req_info->dev, ctx, > - info); > - if (ret == -EOPNOTSUPP) > - break; > - if (ret) > - return ret; > + for (; phase <= ETHTOOL_LOOPBACK_COMPONENT_MODULE; phase++) { > + for (;; idx++) { > + req_info->component = phase; > + req_info->index = idx; > + ret = ethnl_default_dump_one(skb, ctx->req_info->dev, > + ctx, info); > + if (ret == -EOPNOTSUPP) > + break; > + if (ret) { > + *pos_sub = ((unsigned long)phase << 16) | idx; > + return ret; > + } > + } > + idx = 0; > } > > *pos_sub = 0; > - > return 0; > } > > > -- > 2.53.0 >
