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SubjectRe: [PATCH net-next RFC v5 01/15] devlink: Add reload action option to devlink reload command
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On 9/23/2020 9:25 PM, Jakub Kicinski wrote:
>
> On Fri, 18 Sep 2020 19:06:37 +0300 Moshe Shemesh wrote:
>> Add devlink reload action to allow the user to request a specific reload
>> action. The action parameter is optional, if not specified then devlink
>> driver re-init action is used (backward compatible).
>> Note that when required to do firmware activation some drivers may need
>> to reload the driver. On the other hand some drivers may need to reset
>> the firmware to reinitialize the driver entities. Therefore, the devlink
>> reload command returns the actions which were actually performed.
>> Reload actions supported are:
>> driver_reinit: driver entities re-initialization, applying devlink-param
>> and devlink-resource values.
>> fw_activate: firmware activate.
>>
>> command examples:
>> $devlink dev reload pci/0000:82:00.0 action driver_reinit
>> reload_actions_performed:
>> driver_reinit
>>
>> $devlink dev reload pci/0000:82:00.0 action fw_activate
>> reload_actions_performed:
>> driver_reinit fw_activate
>>
>> Signed-off-by: Moshe Shemesh <moshe@mellanox.com>
>> @@ -3971,15 +3972,19 @@ static int mlx4_devlink_reload_up(struct devlink *devlink,
>> int err;
>>
>> err = mlx4_restart_one_up(persist->pdev, true, devlink);
>> - if (err)
>> + if (err) {
>> mlx4_err(persist->dev, "mlx4_restart_one_up failed, ret=%d\n",
>> err);
>> + return err;
>> + }
>> + *actions_performed = BIT(DEVLINK_RELOAD_ACTION_DRIVER_REINIT);
> FWIW I think drivers should be able to assign this even if they return
> an error. On error there is no certainty what actions were actually
> performed (e.g. when timeout happened but the device did the reset a
> little later) so this argument should not be interpreted in presence of
> errors, anyway.


Not sure I got it. Do you mean driver can assign it anyway and devlink
should ignore in case of failure ?

As I implemented here devlink already ignores actions_performed in case
driver returns with error.

> Also consider providing a second enum for the BIT(xyz)s.
OK.
>> -static bool devlink_reload_supported(const struct devlink *devlink)
>> +static bool devlink_reload_supported(const struct devlink_ops *ops)
>> {
>> - return devlink->ops->reload_down && devlink->ops->reload_up;
>> + return ops->reload_down && ops->reload_up;
>> }
> Please make the change to devlink_reload_supported() a separate patch.


Ack.

>> -
>> +
> What is this white space funk? 🤔


Missed that.

>> static void devlink_reload_failed_set(struct devlink *devlink,
>> bool reload_failed)
>> {
>> @@ -2969,32 +2975,79 @@ bool devlink_is_reload_failed(const struct devlink *devlink)
>> EXPORT_SYMBOL_GPL(devlink_is_reload_failed);
>>
>> static int devlink_reload(struct devlink *devlink, struct net *dest_net,
>> - struct netlink_ext_ack *extack)
>> + enum devlink_reload_action action, struct netlink_ext_ack *extack,
>> + unsigned long *actions_performed)
>> {
>> int err;
>>
>> if (!devlink->reload_enabled)
>> return -EOPNOTSUPP;
>>
>> - err = devlink->ops->reload_down(devlink, !!dest_net, extack);
>> + err = devlink->ops->reload_down(devlink, !!dest_net, action, extack);
>> if (err)
>> return err;
>>
>> if (dest_net && !net_eq(dest_net, devlink_net(devlink)))
>> devlink_reload_netns_change(devlink, dest_net);
>>
>> - err = devlink->ops->reload_up(devlink, extack);
>> + err = devlink->ops->reload_up(devlink, action, extack, actions_performed);
>> devlink_reload_failed_set(devlink, !!err);
>> - return err;
>> + if (err)
>> + return err;
>> +
>> + WARN_ON(!test_bit(action, actions_performed));
>> + return 0;
>> +}
>> +
>> +static int
>> +devlink_nl_reload_actions_performed_fill(struct sk_buff *msg,
>> + struct devlink *devlink,
>> + unsigned long actions_performed,
>> + enum devlink_command cmd, u32 portid,
>> + u32 seq, int flags)
>> +{
>> + struct nlattr *actions_performed_attr;
>> + void *hdr;
>> + int i;
>> +
>> + hdr = genlmsg_put(msg, portid, seq, &devlink_nl_family, flags, cmd);
>> + if (!hdr)
>> + return -EMSGSIZE;
>> +
>> + if (devlink_nl_put_handle(msg, devlink))
>> + goto genlmsg_cancel;
>> +
>> + actions_performed_attr = nla_nest_start(msg, DEVLINK_ATTR_RELOAD_ACTIONS_PERFORMED);
>> + if (!actions_performed_attr)
>> + goto genlmsg_cancel;
>> +
>> + for (i = 0; i <= DEVLINK_RELOAD_ACTION_MAX; i++) {
>> + if (!test_bit(i, &actions_performed))
>> + continue;
>> + if (nla_put_u8(msg, DEVLINK_ATTR_RELOAD_ACTION, i))
>> + goto actions_performed_nest_cancel;
> Why not just return a mask? You need a special attribute for the nest,
> anyway..
>
> User space would probably actually prefer to have a single attr than an
> iteration over a nest...
OK.
>> + }
>> + nla_nest_end(msg, actions_performed_attr);
>> + genlmsg_end(msg, hdr);
>> + return 0;
>> +
>> +actions_performed_nest_cancel:
>> + nla_nest_cancel(msg, actions_performed_attr);
>> +genlmsg_cancel:
>> + genlmsg_cancel(msg, hdr);
>> + return -EMSGSIZE;
>> }
>>
>> static int devlink_nl_cmd_reload(struct sk_buff *skb, struct genl_info *info)
>> {
>> struct devlink *devlink = info->user_ptr[0];
>> + enum devlink_reload_action action;
>> + unsigned long actions_performed;
>> struct net *dest_net = NULL;
>> + struct sk_buff *msg;
>> int err;
>>
>> - if (!devlink_reload_supported(devlink))
>> + if (!devlink_reload_supported(devlink->ops))
>> return -EOPNOTSUPP;
>>
>> err = devlink_resources_validate(devlink, NULL, info);
>> @@ -3011,12 +3064,43 @@ static int devlink_nl_cmd_reload(struct sk_buff *skb, struct genl_info *info)
>> return PTR_ERR(dest_net);
>> }
>>
>> - err = devlink_reload(devlink, dest_net, info->extack);
>> + if (info->attrs[DEVLINK_ATTR_RELOAD_ACTION])
>> + action = nla_get_u8(info->attrs[DEVLINK_ATTR_RELOAD_ACTION]);
>> + else
>> + action = DEVLINK_RELOAD_ACTION_DRIVER_REINIT;
>> +
>> + if (action == DEVLINK_RELOAD_ACTION_UNSPEC) {
>> + NL_SET_ERR_MSG_MOD(info->extack, "Invalid reload action");
>> + return -EINVAL;
>> + } else if (!devlink_reload_action_is_supported(devlink, action)) {
>> + NL_SET_ERR_MSG_MOD(info->extack, "Requested reload action is not supported by the driver");
>> + return -EOPNOTSUPP;
>> + }
>> +
>> + err = devlink_reload(devlink, dest_net, action, info->extack, &actions_performed);
> Perhaps we can pass the requested action to the driver via
> actions_performed already, and then all the drivers which
> only do what they're asked to don't have to touch it?


Not sure about it. Note that in the next patch I add here limit_level
and that has only input param, so I think it would be confusing.

>> if (dest_net)
>> put_net(dest_net);
>>
>> - return err;
>> + if (err)
>> + return err;
>> + /* For backward compatibility generate reply only if attributes used by user */
>> + if (!info->attrs[DEVLINK_ATTR_RELOAD_ACTION])
>> + return 0;
>> +
>> + msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
>> + if (!msg)
>> + return -ENOMEM;
>> +
>> + err = devlink_nl_reload_actions_performed_fill(msg, devlink, actions_performed,
>> + DEVLINK_CMD_RELOAD, info->snd_portid,
>> + info->snd_seq, 0);
>> + if (err) {
>> + nlmsg_free(msg);
>> + return err;
>> + }
>> +
>> + return genlmsg_reply(msg, info);
> Are you using devlink_nl_reload_actions_performed_fill() somewhere else?
No
> I'd move the nlmsg_new() / genlmsg_reply() into the helper.


Can do it, but there are many _fill() functions in devlink.c code to
fill the data, none of them include nlmsg_new() and genlmsg_reply()
that's always in the calling function, even if the calling function adds
only that. So I guess I will leave it for consistency.

>> }
>>
>> static int devlink_nl_flash_update_fill(struct sk_buff *msg,
>> @@ -7069,6 +7153,7 @@ static const struct nla_policy devlink_nl_policy[DEVLINK_ATTR_MAX + 1] = {
>> [DEVLINK_ATTR_TRAP_POLICER_RATE] = { .type = NLA_U64 },
>> [DEVLINK_ATTR_TRAP_POLICER_BURST] = { .type = NLA_U64 },
>> [DEVLINK_ATTR_PORT_FUNCTION] = { .type = NLA_NESTED },
>> + [DEVLINK_ATTR_RELOAD_ACTION] = { .type = NLA_U8 },
> Why not just range validation here?


All devlink attributes that pass here go through devlink_nl_poicy this
way, including other enums.

I think changing that should be in a different patch for all, not in
this patchset.

>> };
>>
>> static const struct genl_ops devlink_nl_ops[] = {
>> @@ -7402,6 +7487,20 @@ static struct genl_family devlink_nl_family __ro_after_init = {
>> .n_mcgrps = ARRAY_SIZE(devlink_nl_mcgrps),
>> };
>>
>> +static bool devlink_reload_actions_valid(const struct devlink_ops *ops)
>> +{
>> + if (!devlink_reload_supported(ops)) {
>> + if (WARN_ON(ops->supported_reload_actions))
>> + return false;
>> + return true;
>> + }
>> +
>> + if (WARN_ON(ops->supported_reload_actions >= BIT(__DEVLINK_RELOAD_ACTION_MAX) ||
>> + ops->supported_reload_actions <= BIT(DEVLINK_RELOAD_ACTION_UNSPEC)))
> This won't protect you from ACTION_UNSPEC being set..
>
> WARN_ON(ops->supported_reload_actions & ~GENMASK(...))


Right, I will fix.

>> + return false;
>> + return true;
>> +}

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