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Date: Fri, 02 Nov 2018 09:53:03 +1100
From: Samuel Mendoza-Jonas <sam@...dozajonas.com>
To: Justin.Lee1@...l.com, netdev@...r.kernel.org
Cc: davem@...emloft.net, linux-kernel@...r.kernel.org,
openbmc@...ts.ozlabs.org
Subject: Re: [PATCH net-next 5/6] net/ncsi: Reset channel state in
ncsi_start_dev()
On Tue, 2018-10-30 at 21:26 +0000, Justin.Lee1@...l.com wrote:
> > +int ncsi_reset_dev(struct ncsi_dev *nd)
> > +{
> > + struct ncsi_dev_priv *ndp = TO_NCSI_DEV_PRIV(nd);
> > + struct ncsi_channel *nc, *active;
> > + struct ncsi_package *np;
> > + unsigned long flags;
> > + bool enabled;
> > + int state;
> > +
> > + active = NULL;
> > + NCSI_FOR_EACH_PACKAGE(ndp, np) {
> > + NCSI_FOR_EACH_CHANNEL(np, nc) {
> > + spin_lock_irqsave(&nc->lock, flags);
> > + enabled = nc->monitor.enabled;
> > + state = nc->state;
> > + spin_unlock_irqrestore(&nc->lock, flags);
> > +
> > + if (enabled)
> > + ncsi_stop_channel_monitor(nc);
> > + if (state == NCSI_CHANNEL_ACTIVE) {
> > + active = nc;
> > + break;
>
> Is the original intention to process the channel one by one?
> If it is the case, there are two loops and we might need to use
> "goto found" instead.
Yes we'll need to break out of the package loop here as well.
>
> > + }
> > + }
> > + }
> > +
>
> found: ?
>
> > + if (!active) {
> > + /* Done */
> > + spin_lock_irqsave(&ndp->lock, flags);
> > + ndp->flags &= ~NCSI_DEV_RESET;
> > + spin_unlock_irqrestore(&ndp->lock, flags);
> > + return ncsi_choose_active_channel(ndp);
> > + }
> > +
> > + spin_lock_irqsave(&ndp->lock, flags);
> > + ndp->flags |= NCSI_DEV_RESET;
> > + ndp->active_channel = active;
> > + ndp->active_package = active->package;
> > + spin_unlock_irqrestore(&ndp->lock, flags);
> > +
> > + nd->state = ncsi_dev_state_suspend;
> > + schedule_work(&ndp->work);
> > + return 0;
> > +}
>
> Also similar issue in ncsi_choose_active_channel() function below.
>
> > @@ -916,32 +1045,49 @@ static int ncsi_choose_active_channel(struct ncsi_dev_priv *ndp)
> >
> > ncm = &nc->modes[NCSI_MODE_LINK];
> > if (ncm->data[2] & 0x1) {
> > - spin_unlock_irqrestore(&nc->lock, flags);
> > found = nc;
> > - goto out;
> > + with_link = true;
> > }
> >
> > - spin_unlock_irqrestore(&nc->lock, flags);
> > + /* If multi_channel is enabled configure all valid
> > + * channels whether or not they currently have link
> > + * so they will have AENs enabled.
> > + */
> > + if (with_link || np->multi_channel) {
>
> I notice that there is a case that we will misconfigure the interface.
> For example below, multi-channel is not enable for package 1.
> But we enable the channel for ncsi2 below (package 1 channel 0) as that interface is the first
> channel for that package with link.
I don't think I see the issue here; multi-channel is not set on package
1, but both channels are in the channel whitelist. Channel 0 is
configured since it's the first found on package 1, and channel 1 is not
since channel 0 is already found. Are you expecting something different?
>
> cat /sys/kernel/debug/ncsi_protocol/ncsi_device_
> IFIDX IFNAME NAME PID CID RX TX MP MC WP WC PC CS PS LS RU CR NQ HA
> =====================================================================
> 2 eth2 ncsi0 000 000 1 1 1 1 1 1 0 2 1 1 1 1 0 1
> 2 eth2 ncsi1 000 001 1 0 1 1 1 1 0 2 1 1 1 1 0 1
> 2 eth2 ncsi2 001 000 1 0 1 0 1 1 0 2 1 1 1 1 0 1
> 2 eth2 ncsi3 001 001 0 0 1 0 1 1 0 1 0 1 1 1 0 1
> =====================================================================
> MP: Multi-mode Package WP: Whitelist Package
> MC: Multi-mode Channel WC: Whitelist Channel
> PC: Primary Channel CS: Channel State IA/A/IV 1/2/3
> PS: Poll Status LS: Link Status
> RU: Running CR: Carrier OK
> NQ: Queue Stopped HA: Hardware Arbitration
>
> I temporally change to the following to avoid that.
> if ((with_link &&
> !np->multi_channel &&
> list_empty(&ndp->channel_queue)) || np->multi_channel) {
>
> > + spin_lock_irqsave(&ndp->lock, flags);
> > + list_add_tail_rcu(&nc->link,
> > + &ndp->channel_queue);
> > + spin_unlock_irqrestore(&ndp->lock, flags);
> > +
> > + netdev_dbg(ndp->ndev.dev,
> > + "NCSI: Channel %u added to queue (link %s)\n",
> > + nc->id,
> > + ncm->data[2] & 0x1 ? "up" : "down");
> > + }
> > +
> > + spin_unlock_irqrestore(&nc->lock, cflags);
> > +
> > + if (with_link && !np->multi_channel)
> > + break;
>
> Similar issue here. As we are using break, so each package will configure one active TX.
>
I believe this is handled properly in ncsi_channel_is_tx() in the most
recent revision.
> > }
> > + if (with_link && !ndp->multi_package)
> > + break;
> > }
> >
> > - if (!found) {
> > + if (list_empty(&ndp->channel_queue) && found) {
> > + netdev_info(ndp->ndev.dev,
> > + "NCSI: No channel with link found, configuring channel %u\n",
> > + found->id);
> > + spin_lock_irqsave(&ndp->lock, flags);
> > + list_add_tail_rcu(&found->link, &ndp->channel_queue);
> > + spin_unlock_irqrestore(&ndp->lock, flags);
> > + } else if (!found) {
> > netdev_warn(ndp->ndev.dev,
> > - "NCSI: No channel found with link\n");
> > + "NCSI: No channel found to configure!\n");
> > ncsi_report_link(ndp, true);
> > return -ENODEV;
> > }
>
> Also, for deselect package handler function, do we want to set to inactive here?
> If we just change the state, the cached data still keeps the old value. If the new
> ncsi_reset_dev() function is handling one by one, can we skip this part?
Technically yes we could skip the state change here since
ncsi_reset_dev() will have already done it. However if we send a DP
command via some other means then it is probably best to ensure we treat
all channels on that package as inactive.
>
> static int ncsi_rsp_handler_dp(struct ncsi_request *nr)
> {
> struct ncsi_rsp_pkt *rsp;
> struct ncsi_dev_priv *ndp = nr->ndp;
> struct ncsi_package *np;
> struct ncsi_channel *nc;
> unsigned long flags;
>
> /* Find the package */
> rsp = (struct ncsi_rsp_pkt *)skb_network_header(nr->rsp);
> ncsi_find_package_and_channel(ndp, rsp->rsp.common.channel,
> &np, NULL);
> if (!np)
> return -ENODEV;
>
> /* Change state of all channels attached to the package */
> NCSI_FOR_EACH_CHANNEL(np, nc) {
> spin_lock_irqsave(&nc->lock, flags);
> nc->state = NCSI_CHANNEL_INACTIVE;
>
> spin_unlock_irqrestore(&nc->lock, flags);
> }
>
> return 0;
> }
>
>
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