Hi Florian, Florian Fainelli <f.faine...@gmail.com> writes:
> On 10/12/2017 03:51 PM, Vivien Didelot wrote: >> The dsa_port structure has a "netdev" member, which can be used for >> either the master device, or the slave device, depending on its type. >> >> It is true that today, CPU port are not exposed to userspace, thus the >> port's netdev member can be used to point to its master interface. >> >> But it is still slightly confusing, so split it into more explicit >> "master" and "slave" members. > > I do see some value in doing that, although I also see value in having > structure members be named after what they are, rather than their use > (oh well, it's all debatable anyway), see below for a suggestion on how > to reconcile the two: > >> struct dsa_port { >> + /* Master device, physically connected if this is a CPU port */ >> + struct net_device *master; >> + >> + /* Slave device, if this port is exposed to userspace */ >> + struct net_device *slave; >> + > > How about using: > > union { > struct net_device *master; > struct net_device *slave; > } netdev; > > Such that this serves both purposes of clearly communicating what the > structure member is, and it can be either one of the two, but not both > at the same time? I love that! It makes clear that master is not available for a non-CPU port. Using this union is correct for the moment because DSA and CPU ports don't have a slave device attached to them. If this becomes true one day (unlikely), we'll remove the union. Thanks, Vivien