Re: [PATCH 5/9] net: ethernet: ti: cpts: add return value to tx and rx timestamp funcitons

From: Richard Cochran
Date: Wed Sep 14 2016 - 10:00:34 EST


On Wed, Sep 14, 2016 at 04:02:27PM +0300, Grygorii Strashko wrote:
> From: WingMan Kwok <w-kwok2@xxxxxx>
>
> Added return values in tx and rx timestamp funcitons facilitate the
> possibililies of timestamping by CPSW modules other than CPTS, such as
> packet accelerator on Keystone 2 devices.

I'm sorry, this is totally bogus.

> Signed-off-by: WingMan Kwok <w-kwok2@xxxxxx>
> Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
> ---
> drivers/net/ethernet/ti/cpts.c | 16 ++++++++++------
> drivers/net/ethernet/ti/cpts.h | 11 +++++++----
> 2 files changed, 17 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/net/ethernet/ti/cpts.c b/drivers/net/ethernet/ti/cpts.c
> index 1ee64c6..970d4e2 100644
> --- a/drivers/net/ethernet/ti/cpts.c
> +++ b/drivers/net/ethernet/ti/cpts.c
> @@ -302,34 +302,38 @@ static u64 cpts_find_ts(struct cpts *cpts, struct sk_buff *skb, int ev_type)
> return ns;
> }
>
> -void cpts_rx_timestamp(struct cpts *cpts, struct sk_buff *skb)
> +int cpts_rx_timestamp(struct cpts *cpts, struct sk_buff *skb)
> {
> u64 ns;
> struct skb_shared_hwtstamps *ssh;
>
> if (!cpts || !cpts->rx_enable)
> - return;
> + return -EPERM;

EPERM? Come on.

> ns = cpts_find_ts(cpts, skb, CPTS_EV_RX);
> if (!ns)
> - return;
> + return -ENOENT;
> ssh = skb_hwtstamps(skb);
> memset(ssh, 0, sizeof(*ssh));
> ssh->hwtstamp = ns_to_ktime(ns);
> +
> + return 0;
> }
>
> -void cpts_tx_timestamp(struct cpts *cpts, struct sk_buff *skb)
> +int cpts_tx_timestamp(struct cpts *cpts, struct sk_buff *skb)
> {
> u64 ns;
> struct skb_shared_hwtstamps ssh;
>
> if (!cpts || !(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
> - return;
> + return -EPERM;
> ns = cpts_find_ts(cpts, skb, CPTS_EV_TX);
> if (!ns)
> - return;
> + return -ENOENT;
> memset(&ssh, 0, sizeof(ssh));
> ssh.hwtstamp = ns_to_ktime(ns);
> skb_tstamp_tx(skb, &ssh);
> +
> + return 0;
> }
>
> int cpts_register(struct cpts *cpts)
> diff --git a/drivers/net/ethernet/ti/cpts.h b/drivers/net/ethernet/ti/cpts.h
> index a865193..47026ec 100644
> --- a/drivers/net/ethernet/ti/cpts.h
> +++ b/drivers/net/ethernet/ti/cpts.h
> @@ -129,8 +129,8 @@ struct cpts {
> struct cpts_event pool_data[CPTS_MAX_EVENTS];
> };
>
> -void cpts_rx_timestamp(struct cpts *cpts, struct sk_buff *skb);
> -void cpts_tx_timestamp(struct cpts *cpts, struct sk_buff *skb);
> +int cpts_rx_timestamp(struct cpts *cpts, struct sk_buff *skb);
> +int cpts_tx_timestamp(struct cpts *cpts, struct sk_buff *skb);
> int cpts_register(struct cpts *cpts);
> void cpts_unregister(struct cpts *cpts);
> struct cpts *cpts_create(struct device *dev, void __iomem *regs,
> @@ -162,11 +162,14 @@ static inline bool cpts_is_tx_enabled(struct cpts *cpts)
> #else
> struct cpts;
>
> -static inline void cpts_rx_timestamp(struct cpts *cpts, struct sk_buff *skb)
> +static inline int cpts_rx_timestamp(struct cpts *cpts, struct sk_buff *skb)
> {
> + return -EOPNOTSUPP;

You are planning to check in the hot path if a compile time feature is
enabled?

Brilliant stuff.

> }
> -static inline void cpts_tx_timestamp(struct cpts *cpts, struct sk_buff *skb)
> +
> +static inline int cpts_tx_timestamp(struct cpts *cpts, struct sk_buff *skb)
> {
> + return -EOPNOTSUPP;
> }
>
> static inline
> --
> 2.9.3
>

Thanks,
Richard