28/06/2017 13:58, Jan Blunck: > On Wed, Jun 28, 2017 at 1:44 PM, Thomas Monjalon <tho...@monjalon.net> wrote: > > 27/06/2017 21:03, Jan Blunck: > >> On Tue, Jun 27, 2017 at 6:11 PM, Gaetan Rivet <gaetan.ri...@6wind.com> > >> wrote: > >> > --- a/lib/librte_eal/common/include/rte_bus.h > >> > +++ b/lib/librte_eal/common/include/rte_bus.h > >> > /** > >> > + * Implementation specific probe function which is responsible for > >> > linking > >> > + * devices on that bus with applicable drivers. > >> > + * The plugged device might already have been used previously by the > >> > bus, > >> > + * in which case some buses might prefer to detect and re-use the > >> > relevant > >> > + * information pertaining to this device. > >> > + * > >> > + * @param da > >> > + * Device declaration. > >> > + * > >> > + * @return > >> > + * The pointer to a valid rte_device usable by the bus on success. > >> > + * NULL on error. rte_errno is then set. > >> > + */ > >> > +typedef struct rte_device * (*rte_bus_plug_t)(struct rte_devargs *da); > >> > >> Shouldn't this be orthogonal to unplug() and take a rte_device. You > >> should only be able to plug devices that have been found by scan > >> before. > > > > Plugging a device that has been scanned before is a special case. > > In a true hotplug scenario, we could use this plug function passing > > a devargs. > > I don't see any issue passing rte_devargs to plug and rte_device to unplug. > > What do you mean by "true hotplug"?
I mean a kernel notification of a new device. > The problem with this is that passing just rte_devargs to plug() > requires the bus to parse and enrich the rte_devargs with bus > specifics. From there it gets folded into the to-be-created bus > specific rte_XXX_device. This makes it unnecessarily complicated and > even worse it adds a second code path how devices come alive. Just after the notification, the rte_device does not exist yet. So the plug function could share the same code as the scan function to get the metadata and create the device instance. > When we get notified about a hotplug event we already know which bus > this event belongs to: > > 1. scan the bus for incoming devices No need to scan every devices here. > 2. plug single device with devargs and probe for drivers > > Makes sense? I want to make sure there is no misunderstanding first :)
