On Wed, May 01, 2024 at 01:31:34AM +0800, Heng Qi wrote:
...
> diff --git a/include/linux/dim.h b/include/linux/dim.h
...
> @@ -198,6 +234,32 @@ enum dim_step_result {
> DIM_ON_EDGE,
> };
>
> +/**
> + * net_dim_init_irq_moder - collect information to initialize irq moderation
> + * @dev: target network device
> + * @profile_flags: Rx or Tx profile modification capability
> + * @coal_flags: irq moderation params flags
> + * @rx_mode: CQ period mode for Rx
> + * @tx_mode: CQ period mode for Tx
> + * @rx_dim_work: Rx worker called after dim decision
> + * void (*rx_dim_work)(struct work_struct *work);
> + *
> + * @tx_dim_work: Tx worker called after dim decision
> + * void (*tx_dim_work)(struct work_struct *work);
> + *
Hi Heng Qi,
The above seems to result in make htmldocs issuing the following warnings:
.../net_dim:175: ./include/linux/dim.h:244: WARNING: Inline emphasis start-string without end-string.
.../net_dim:175: ./include/linux/dim.h:244: WARNING: Inline emphasis start-string without end-string.
.../net_dim:175: ./include/linux/dim.h:247: WARNING: Inline emphasis start-string without end-string.
.../net_dim:175: ./include/linux/dim.h:247: WARNING: Inline emphasis start-string without end-string.
I suggest the following alternative:
* @rx_dim_work: Rx worker called after dim decision
* @tx_dim_work: Tx worker called after dim decision
Exercised using Sphinx 7.2.6
...
> diff --git a/net/ethtool/coalesce.c b/net/ethtool/coalesce.c
...
> @@ -134,6 +212,12 @@ static int coalesce_fill_reply(struct sk_buff *skb,
> const struct coalesce_reply_data *data = COALESCE_REPDATA(reply_base);
> const struct kernel_ethtool_coalesce *kcoal = &data->kernel_coalesce;
> const struct ethtool_coalesce *coal = &data->coalesce;
> +#if IS_ENABLED(CONFIG_DIMLIB)
> + struct net_device *dev = req_base->dev;
> + struct dim_irq_moder *moder = dev->irq_moder;
> + u8 coal_flags;
> + int ret;
> +#endif
> u32 supported = data->supported_params;
It's a minor nit, but here goes: please consider using reverse xmas tree
order - longest line to shortest - for local variable declarations in
Networking code.
In this case, I appreciate that it's not strictly possible without
introducing more than one IS_ENABLED condition, which seems worse.
So, as that condition breaks the visual flow, what I suggest in this
case is having a second block of local variable declarations, like this:
const struct coalesce_reply_data *data = COALESCE_REPDATA(reply_base);
const struct kernel_ethtool_coalesce *kcoal = &data->kernel_coalesce;
const struct ethtool_coalesce *coal = &data->coalesce;
u32 supported = data->supported_params;
#if IS_ENABLED(CONFIG_DIMLIB)
struct dim_irq_moder *moder = dev->irq_moder;
struct net_device *dev = req_base->dev;
u8 coal_flags;
int ret;
#endif
Or better still, if it can be done cleanly, moving all the IS_ENABLED()
code in this function into a separate function, with an no-op
implementation in the case that CONFIG_DIMLIB is not enabled. In general
I'd recommend that approach over sprinkling IS_ENABLED or #ifdef inside
functions. Because in my experience it tends to lead to more readable code.
In any case, the following tool is helpful for isolating
reverse xmas tree issues.
https://github.com/ecree-solarflare/xmastree
> if (coalesce_put_u32(skb, ETHTOOL_A_COALESCE_RX_USECS,
> @@ -192,11 +276,49 @@ static int coalesce_fill_reply(struct sk_buff *skb,
> kcoal->tx_aggr_time_usecs, supported))
> return -EMSGSIZE;
>
> +#if IS_ENABLED(CONFIG_DIMLIB)
> + if (!moder)
> + return 0;
> +
> + coal_flags = moder->coal_flags;
> + rcu_read_lock();
> + if (moder->profile_flags & DIM_PROFILE_RX) {
> + ret = coalesce_put_profile(skb, ETHTOOL_A_COALESCE_RX_PROFILE,
> + rcu_dereference(moder->rx_profile),
> + coal_flags);
> + if (ret) {
> + rcu_read_unlock();
> + return ret;
> + }
> + }
> +
> + if (moder->profile_flags & DIM_PROFILE_TX) {
> + ret = coalesce_put_profile(skb, ETHTOOL_A_COALESCE_TX_PROFILE,
> + rcu_dereference(moder->tx_profile),
> + coal_flags);
> + if (ret) {
> + rcu_read_unlock();
> + return ret;
> + }
> + }
> + rcu_read_unlock();
> +#endif
> return 0;
> }
...
