Re: [PATCH] ethdev: fix push new event

[Thomas Monjalon <thomas@monjalon.net>]

28/05/2022 10:53, lihuisong (C):
> 
> 在 2022/5/23 22:36, Thomas Monjalon 写道:
> > 23/05/2022 11:51, David Marchand:
> >> On Sat, May 21, 2022 at 8:57 AM Min Hu (Connor)<humin29@huawei.com>  wrote:
> >>> From: Huisong Li<lihuisong@huawei.com>
> >>>
> >>> The 'state' in struct rte_eth_dev may be used to update some information
> >>> when app receive these events. For example, when app receives a new event,
> >>> app may get the socket id of this port by calling rte_eth_dev_socket_id to
> >>> setup the attached port. The 'state' is used in rte_eth_dev_socket_id.
> >>>
> >>> If the state isn't modified to RTE_ETH_DEV_ATTACHED before pushing the new
> >>> event, app will get the socket id failed. So this patch moves pushing event
> >>> operation after the state updated.
> >>>
> >>> Fixes: 99a2dd955fba ("lib: remove librte_ prefix from directory names")
> >> A patch moving code is unlikely to be at fault.
> >>
> >>
> >> Looking at the patch which moved those notifications in this point of
> >> the code, the state update was pushed after the notification on
> >> purpose.
> >> See be8cd210379a ("ethdev: fix port probing notification")
> >>
> >>      ethdev: fix port probing notification
> >>
> >>      The new device was notified as soon as it was allocated.
> >>      It leads to use a device which is not yet initialized.
> >>
> >>      The notification must be published after the initialization is done
> >>      by the PMD, but before the state is changed, in order to let
> >>      notified entities taking ownership before general availability.
> >>
> >>
> >> Do we need an intermediate state during probing?
> > Possibly. Currently we have only 3 states:
> > 	RTE_ETH_DEV_UNUSED
> > 	RTE_ETH_DEV_ATTACHED
> > 	RTE_ETH_DEV_REMOVED
> >
> > We may add RTE_ETH_DEV_ALLOCATED just before calling
> > 	rte_eth_dev_callback_process(dev, RTE_ETH_EVENT_NEW, NULL);
> > Then we would need to check against RTE_ETH_DEV_ALLOCATED
> > in some ethdev functions.
> >
> Hi, Thomas,
> 
> Do you mean that we need to modify some funcions like following?
> 
> int rte_eth_dev_is_valid_port(uint16_t port_id)
> {
>      if (port_id >= RTE_MAX_ETHPORTS ||
>          (rte_eth_devices[port_id].state != *RTE_ETH_DEV_ALLOCATED*))
>          return 0;
>      else
>          return 1;
> }
> 
> uint16_t rte_eth_find_next(uint16_t port_id)
> {
>      while (port_id < RTE_MAX_ETHPORTS &&
>              rte_eth_devices[port_id].state != *RTE_ETH_DEV_ALLOCATED*)
>          port_id++;
> 
>      if (port_id >= RTE_MAX_ETHPORTS)
>          return RTE_MAX_ETHPORTS;
> 
>      return port_id;
> }

Yes this is what I mean.