> -----Original Message-----
> From: Burakov, Anatoly
> Sent: Thursday, June 21, 2018 5:06 PM
> To: Zhang, Qi Z <qi.z.zh...@intel.com>; tho...@monjalon.net
> Cc: Ananyev, Konstantin <konstantin.anan...@intel.com>; dev@dpdk.org;
> Richardson, Bruce <bruce.richard...@intel.com>; Yigit, Ferruh
> <ferruh.yi...@intel.com>; Shelton, Benjamin H
> <benjamin.h.shel...@intel.com>; Vangati, Narender
> <narender.vang...@intel.com>
> Subject: Re: [PATCH v2 06/22] ethdev: support attach or detach share device
> from secondary
>
> On 21-Jun-18 3:00 AM, Qi Zhang wrote:
> > This patch cover the multi-process hotplug case when a share device
> > attach/detach request be issued from secondary process, the
> > implementation references malloc_mp.c.
> >
> > device attach on secondary:
> > a) secondary send async request to primary and wait on a condition
> > which will be released by matched response from primary.
> > b) primary receive the request and attach the new device if failed
> > goto i).
> > c) primary forward attach request to all secondary as async request
> > (because this in mp thread context, use sync request will
> > deadlock)
> > d) secondary receive request and attach device and send reply.
> > e) primary check the reply if all success go to j).
> > f) primary send attach rollback async request to all secondary.
> > g) secondary receive the request and detach device and send reply.
> > h) primary receive the reply and detach device as rollback action.
> > i) send fail response to secondary, goto k).
> > j) send success response to secondary.
> > k) secondary process receive response and return.
> >
> > device detach on secondary:
> > a) secondary send async request to primary and wait on a condition
> > which will be released by matched response from primary.
> > b) primary receive the request and perform pre-detach check, if device
> > is locked, goto j).
> > c) primary send pre-detach async request to all secondary.
> > d) secondary perform pre-detach check and send reply.
> > e) primary check the reply if any fail goto j).
> > f) primary send detach async request to all secondary
> > g) secondary detach the device and send reply
> > h) primary detach the device.
> > i) send success response to secondary, goto k).
> > j) send fail response to secondary.
> > k) secondary process receive response and return.
> >
> > Signed-off-by: Qi Zhang <qi.z.zh...@intel.com>
> > ---
> >
>
> <snip>
>
> > -static int handle_secondary_request(const struct rte_mp_msg *msg,
> > const void *peer)
> > +static int
> > +check_reply(const struct eth_dev_mp_req *req, const struct
> > +rte_mp_reply *reply) {
> > + struct eth_dev_mp_req *resp;
> > + int i;
> > +
> > + if (reply->nb_received != reply->nb_sent)
> > + return -EINVAL;
> > +
> > + for (i = 0; i < reply->nb_received; i++) {
> > + resp = (struct eth_dev_mp_req *)reply->msgs[i].param;
> > +
> > + if (resp->t != req->t) {
> > + ethdev_log(ERR, "Unexpected response to async
> > request\n");
> > + return -EINVAL;
> > + }
> > +
> > + if (resp->id != req->id) {
> > + ethdev_log(ERR, "response to wrong async request\n");
> > + return -EINVAL;
> > + }
> > +
> > + if (resp->result)
> > + return resp->result;
> > + }
> > +
> > + return 0;
> > +}
>
> As far as i understand, return values from this will propagate all the way up
> to
> user return value.
Yes
>How would a user differentiate between -EINVAL returned
> from invalid parameters, and -EINVAL from failed reply?
My understanding is if
(resp->t != req->t) or (resp->id != req->id) is not expected to happen at any
condition.
there should be a bug if it does happen.
So the return value is not necessary to be sensitive.
Am I right?
> I think this error code should be different (don't know which one though
> :) ).
>
> (as a side note, you keep returning -EINVAL all over the place, even when
> problem is not in user's arguments - you should probably fix those too. for
> example, if request ID not found, return code should probably be something
> like -ENOENT)
Yes, -ENOENT is better than -EINVAL for id mismatch?
>
>
> --
> Thanks,
> Anatoly
