On Wed, 17 Jan 2018 14:32:17 +0000 Ferruh Yigit <ferruh.yi...@intel.com> wrote:
> On 1/17/2018 7:56 AM, Andrew Rybchenko wrote: > > On 01/16/2018 09:37 PM, Stephen Hemminger wrote: > >> While reviewing drivers, noticed a lot of unnecessary > >> duplication of code in drivers for handling the eth_dev link status > >> information. While consolidating this, it also became obvious that > >> some drivers behave differently for no good reason. > >> > >> It also was a good chance to introduce atomic exchange primitives > >> in EAL because there are other places using cmpset where not > >> necessary (such as bonding). > >> > >> Mostly only compile tested only, don't have all of the hardware > >> available (except ixgbe and virtio) to test. > >> > >> Note: the eth_dev_link_update function return value is inconsistent > >> across drivers. Should be changed to be void. > > > > I would say "link_update" callback return value is inconsistent across > > drivers. I'm not sure which direction is right here: make it consistent > > or make it void. Also any changes in link information could be > > important. As I understand it should not happen without up/down, > > but bugs with loss of intermediate transitions are definitely possible. > > So, notifying about any changes in link information is definitely safer. > > May be not now. > > Again, why not return previous link status, it is simple enough to prevent > inconsistent usage. > > rte_eth_link_get() already discards the return value, so won't be a problem > there. > > For the cases PMD would like know about link changes, they will need to > implement almost same link_update function with a return value, so why not use > existing link_update function? > > Like been in virtio, link_update() used in interrupt handler, and calls a > callback process if status changes. When link_update() return status changed > to > void, I guess they will need to implement another version of the link_update > with return and use it. The interrupt and non-interrupt model are different. Also the driver internally may want to do something different, this is about the return value for dev_ops->link_update. The code in rte_eth_dev never used the return value. The bonding driver was expecting it to work but it doesn't. Anyway drivers shouldn't in general be directly calling other devices eth_dev_ops
