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Subject[net-next 1/3] net: dsa: optimize tx timestamp request handling
Date
Optimization could be done on dsa_skb_tx_timestamp(), and dsa device
drivers should adapt to it.

- Check SKBTX_HW_TSTAMP request flag at the very beginning, instead of in
port_txtstamp, so that most skbs not requiring tx timestamp just return.

- No longer to identify PTP packets, and limit tx timestamping only for PTP
packets. If device driver likes, let device driver do.

- It is a waste to clone skb directly in dsa_skb_tx_timestamp().
For one-step timestamping, a clone is not needed. For any failure of
port_txtstamp (this may usually happen), the skb clone has to be freed.
So put skb cloning into port_txtstamp where it really needs.

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
---
Documentation/networking/timestamping.rst | 7 +++++--
.../net/dsa/hirschmann/hellcreek_hwtstamp.c | 20 ++++++++++++------
.../net/dsa/hirschmann/hellcreek_hwtstamp.h | 2 +-
drivers/net/dsa/mv88e6xxx/hwtstamp.c | 21 +++++++++++++------
drivers/net/dsa/mv88e6xxx/hwtstamp.h | 6 +++---
drivers/net/dsa/ocelot/felix.c | 11 ++++++----
drivers/net/dsa/sja1105/sja1105_ptp.c | 6 +++++-
drivers/net/dsa/sja1105/sja1105_ptp.h | 2 +-
include/net/dsa.h | 2 +-
net/dsa/slave.c | 20 +++++-------------
10 files changed, 57 insertions(+), 40 deletions(-)

diff --git a/Documentation/networking/timestamping.rst b/Documentation/networking/timestamping.rst
index f682e88fa87e..7f04a699a5d1 100644
--- a/Documentation/networking/timestamping.rst
+++ b/Documentation/networking/timestamping.rst
@@ -635,8 +635,8 @@ in generic code: a BPF classifier (``ptp_classify_raw``) is used to identify
PTP event messages (any other packets, including PTP general messages, are not
timestamped), and provides two hooks to drivers:

-- ``.port_txtstamp()``: The driver is passed a clone of the timestampable skb
- to be transmitted, before actually transmitting it. Typically, a switch will
+- ``.port_txtstamp()``: A clone of the timestampable skb to be transmitted
+ is needed, before actually transmitting it. Typically, a switch will
have a PTP TX timestamp register (or sometimes a FIFO) where the timestamp
becomes available. There may be an IRQ that is raised upon this timestamp's
availability, or the driver might have to poll after invoking
@@ -645,6 +645,9 @@ timestamped), and provides two hooks to drivers:
later use (when the timestamp becomes available). Each skb is annotated with
a pointer to its clone, in ``DSA_SKB_CB(skb)->clone``, to ease the driver's
job of keeping track of which clone belongs to which skb.
+ But one-step timestamping request is handled differently with above two-step
+ timestamping. The skb clone is no longer needed since hardware will insert
+ TX time information on packet during egress.

- ``.port_rxtstamp()``: The original (and only) timestampable skb is provided
to the driver, for it to annotate it with a timestamp, if that is immediately
diff --git a/drivers/net/dsa/hirschmann/hellcreek_hwtstamp.c b/drivers/net/dsa/hirschmann/hellcreek_hwtstamp.c
index 69dd9a2e8bb6..2ff4b7c08b72 100644
--- a/drivers/net/dsa/hirschmann/hellcreek_hwtstamp.c
+++ b/drivers/net/dsa/hirschmann/hellcreek_hwtstamp.c
@@ -374,31 +374,39 @@ long hellcreek_hwtstamp_work(struct ptp_clock_info *ptp)
}

bool hellcreek_port_txtstamp(struct dsa_switch *ds, int port,
- struct sk_buff *clone, unsigned int type)
+ struct sk_buff *skb, struct sk_buff **clone)
{
struct hellcreek *hellcreek = ds->priv;
struct hellcreek_port_hwtstamp *ps;
struct ptp_header *hdr;
+ unsigned int type;

ps = &hellcreek->ports[port].port_hwtstamp;

- /* Check if the driver is expected to do HW timestamping */
- if (!(skb_shinfo(clone)->tx_flags & SKBTX_HW_TSTAMP))
+ type = ptp_classify_raw(skb);
+ if (type == PTP_CLASS_NONE)
return false;

/* Make sure the message is a PTP message that needs to be timestamped
* and the interaction with the HW timestamping is enabled. If not, stop
* here
*/
- hdr = hellcreek_should_tstamp(hellcreek, port, clone, type);
+ hdr = hellcreek_should_tstamp(hellcreek, port, skb, type);
if (!hdr)
return false;

+ *clone = skb_clone_sk(skb);
+ if (!(*clone))
+ return false;
+
if (test_and_set_bit_lock(HELLCREEK_HWTSTAMP_TX_IN_PROGRESS,
- &ps->state))
+ &ps->state)) {
+ kfree_skb(*clone);
+ *clone = NULL;
return false;
+ }

- ps->tx_skb = clone;
+ ps->tx_skb = *clone;

/* store the number of ticks occurred since system start-up till this
* moment
diff --git a/drivers/net/dsa/hirschmann/hellcreek_hwtstamp.h b/drivers/net/dsa/hirschmann/hellcreek_hwtstamp.h
index c0745ffa1ebb..58cc96642076 100644
--- a/drivers/net/dsa/hirschmann/hellcreek_hwtstamp.h
+++ b/drivers/net/dsa/hirschmann/hellcreek_hwtstamp.h
@@ -45,7 +45,7 @@ int hellcreek_port_hwtstamp_get(struct dsa_switch *ds, int port,
bool hellcreek_port_rxtstamp(struct dsa_switch *ds, int port,
struct sk_buff *clone, unsigned int type);
bool hellcreek_port_txtstamp(struct dsa_switch *ds, int port,
- struct sk_buff *clone, unsigned int type);
+ struct sk_buff *skb, struct sk_buff **clone);

int hellcreek_get_ts_info(struct dsa_switch *ds, int port,
struct ethtool_ts_info *info);
diff --git a/drivers/net/dsa/mv88e6xxx/hwtstamp.c b/drivers/net/dsa/mv88e6xxx/hwtstamp.c
index 094d17a1d037..280a95962861 100644
--- a/drivers/net/dsa/mv88e6xxx/hwtstamp.c
+++ b/drivers/net/dsa/mv88e6xxx/hwtstamp.c
@@ -469,24 +469,33 @@ long mv88e6xxx_hwtstamp_work(struct ptp_clock_info *ptp)
}

bool mv88e6xxx_port_txtstamp(struct dsa_switch *ds, int port,
- struct sk_buff *clone, unsigned int type)
+ struct sk_buff *skb, struct sk_buff **clone)
{
struct mv88e6xxx_chip *chip = ds->priv;
struct mv88e6xxx_port_hwtstamp *ps = &chip->port_hwtstamp[port];
struct ptp_header *hdr;
+ unsigned int type;

- if (!(skb_shinfo(clone)->tx_flags & SKBTX_HW_TSTAMP))
- return false;
+ type = ptp_classify_raw(skb);
+ if (type == PTP_CLASS_NONE)
+ return false

- hdr = mv88e6xxx_should_tstamp(chip, port, clone, type);
+ hdr = mv88e6xxx_should_tstamp(chip, port, skb, type);
if (!hdr)
return false;

+ *clone = skb_clone_sk(skb);
+ if (!(*clone))
+ return false;
+
if (test_and_set_bit_lock(MV88E6XXX_HWTSTAMP_TX_IN_PROGRESS,
- &ps->state))
+ &ps->state)) {
+ kfree_skb(*clone);
+ *clone = NULL;
return false;
+ }

- ps->tx_skb = clone;
+ ps->tx_skb = *clone;
ps->tx_tstamp_start = jiffies;
ps->tx_seq_id = be16_to_cpu(hdr->sequence_id);

diff --git a/drivers/net/dsa/mv88e6xxx/hwtstamp.h b/drivers/net/dsa/mv88e6xxx/hwtstamp.h
index 9da9f197ba02..da2b253334d0 100644
--- a/drivers/net/dsa/mv88e6xxx/hwtstamp.h
+++ b/drivers/net/dsa/mv88e6xxx/hwtstamp.h
@@ -118,7 +118,7 @@ int mv88e6xxx_port_hwtstamp_get(struct dsa_switch *ds, int port,
bool mv88e6xxx_port_rxtstamp(struct dsa_switch *ds, int port,
struct sk_buff *clone, unsigned int type);
bool mv88e6xxx_port_txtstamp(struct dsa_switch *ds, int port,
- struct sk_buff *clone, unsigned int type);
+ struct sk_buff *skb, struct sk_buff **clone);

int mv88e6xxx_get_ts_info(struct dsa_switch *ds, int port,
struct ethtool_ts_info *info);
@@ -152,8 +152,8 @@ static inline bool mv88e6xxx_port_rxtstamp(struct dsa_switch *ds, int port,
}

static inline bool mv88e6xxx_port_txtstamp(struct dsa_switch *ds, int port,
- struct sk_buff *clone,
- unsigned int type)
+ struct sk_buff *skb,
+ struct sk_buff **clone)
{
return false;
}
diff --git a/drivers/net/dsa/ocelot/felix.c b/drivers/net/dsa/ocelot/felix.c
index 6b5442be0230..cdec2f5e271c 100644
--- a/drivers/net/dsa/ocelot/felix.c
+++ b/drivers/net/dsa/ocelot/felix.c
@@ -1396,14 +1396,17 @@ static bool felix_rxtstamp(struct dsa_switch *ds, int port,
}

static bool felix_txtstamp(struct dsa_switch *ds, int port,
- struct sk_buff *clone, unsigned int type)
+ struct sk_buff *skb, struct sk_buff **clone)
{
struct ocelot *ocelot = ds->priv;
struct ocelot_port *ocelot_port = ocelot->ports[port];

- if (ocelot->ptp && (skb_shinfo(clone)->tx_flags & SKBTX_HW_TSTAMP) &&
- ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP) {
- ocelot_port_add_txtstamp_skb(ocelot, port, clone);
+ if (ocelot->ptp && ocelot_port->ptp_cmd == IFH_REW_OP_TWO_STEP_PTP) {
+ *clone = skb_clone_sk(skb);
+ if (!(*clone))
+ return false;
+
+ ocelot_port_add_txtstamp_skb(ocelot, port, *clone);
return true;
}

diff --git a/drivers/net/dsa/sja1105/sja1105_ptp.c b/drivers/net/dsa/sja1105/sja1105_ptp.c
index 1b90570b257b..6a1f854a8c33 100644
--- a/drivers/net/dsa/sja1105/sja1105_ptp.c
+++ b/drivers/net/dsa/sja1105/sja1105_ptp.c
@@ -436,7 +436,7 @@ bool sja1105_port_rxtstamp(struct dsa_switch *ds, int port,
* callback, where we will timestamp it synchronously.
*/
bool sja1105_port_txtstamp(struct dsa_switch *ds, int port,
- struct sk_buff *skb, unsigned int type)
+ struct sk_buff *skb, struct sk_buff **clone)
{
struct sja1105_private *priv = ds->priv;
struct sja1105_port *sp = &priv->ports[port];
@@ -444,6 +444,10 @@ bool sja1105_port_txtstamp(struct dsa_switch *ds, int port,
if (!sp->hwts_tx_en)
return false;

+ *clone = skb_clone_sk(skb);
+ if (!(*clone))
+ return false;
+
return true;
}

diff --git a/drivers/net/dsa/sja1105/sja1105_ptp.h b/drivers/net/dsa/sja1105/sja1105_ptp.h
index 3daa33e98e77..ab80b73219cb 100644
--- a/drivers/net/dsa/sja1105/sja1105_ptp.h
+++ b/drivers/net/dsa/sja1105/sja1105_ptp.h
@@ -105,7 +105,7 @@ bool sja1105_port_rxtstamp(struct dsa_switch *ds, int port,
struct sk_buff *skb, unsigned int type);

bool sja1105_port_txtstamp(struct dsa_switch *ds, int port,
- struct sk_buff *skb, unsigned int type);
+ struct sk_buff *skb, struct sk_buff **clone);

int sja1105_hwtstamp_get(struct dsa_switch *ds, int port, struct ifreq *ifr);

diff --git a/include/net/dsa.h b/include/net/dsa.h
index 1259b0f40684..c8415c324e27 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -734,7 +734,7 @@ struct dsa_switch_ops {
int (*port_hwtstamp_set)(struct dsa_switch *ds, int port,
struct ifreq *ifr);
bool (*port_txtstamp)(struct dsa_switch *ds, int port,
- struct sk_buff *clone, unsigned int type);
+ struct sk_buff *skb, struct sk_buff **clone);
bool (*port_rxtstamp)(struct dsa_switch *ds, int port,
struct sk_buff *skb, unsigned int type);

diff --git a/net/dsa/slave.c b/net/dsa/slave.c
index 9300cb66e500..5b746a903ef4 100644
--- a/net/dsa/slave.c
+++ b/net/dsa/slave.c
@@ -19,7 +19,6 @@
#include <linux/if_bridge.h>
#include <linux/if_hsr.h>
#include <linux/netpoll.h>
-#include <linux/ptp_classify.h>

#include "dsa_priv.h"

@@ -555,26 +554,19 @@ static void dsa_skb_tx_timestamp(struct dsa_slave_priv *p,
struct sk_buff *skb)
{
struct dsa_switch *ds = p->dp->ds;
- struct sk_buff *clone;
- unsigned int type;
+ struct sk_buff *clone = NULL;

- type = ptp_classify_raw(skb);
- if (type == PTP_CLASS_NONE)
+ if (!(skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP))
return;

if (!ds->ops->port_txtstamp)
return;

- clone = skb_clone_sk(skb);
- if (!clone)
+ if (!ds->ops->port_txtstamp(ds, p->dp->index, skb, &clone))
return;

- if (ds->ops->port_txtstamp(ds, p->dp->index, clone, type)) {
+ if (clone)
DSA_SKB_CB(skb)->clone = clone;
- return;
- }
-
- kfree_skb(clone);
}

netdev_tx_t dsa_enqueue_skb(struct sk_buff *skb, struct net_device *dev)
@@ -628,9 +620,7 @@ static netdev_tx_t dsa_slave_xmit(struct sk_buff *skb, struct net_device *dev)

DSA_SKB_CB(skb)->clone = NULL;

- /* Identify PTP protocol packets, clone them, and pass them to the
- * switch driver
- */
+ /* Handle tx timestamp request if has */
dsa_skb_tx_timestamp(p, skb);

if (dsa_realloc_skb(skb, dev)) {
--
2.25.1
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