[PATCH net-next v4 05/10] net: ethernet: ti: cpts: optimize packet to event matching

From: Grygorii Strashko
Date: Wed Apr 22 2020 - 16:13:45 EST


Now the CPTS driver performs packet (skb) parsing every time when it needs
to match packet to CPTS event (including ptp_classify_raw() calls).

This patch optimizes matching process by parsing packet only once upon
arrival and stores PTP specific data in skb->cb using the same fromat as in
CPTS HW event. As result, all future matching reduces to comparing two u32
values.

Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
Acked-by: Richard Cochran <richardcochran@xxxxxxxxx>
---
drivers/net/ethernet/ti/cpts.c | 91 ++++++++++++++++++++++------------
1 file changed, 58 insertions(+), 33 deletions(-)

diff --git a/drivers/net/ethernet/ti/cpts.c b/drivers/net/ethernet/ti/cpts.c
index 1f738bb3df74..6efb809d58ed 100644
--- a/drivers/net/ethernet/ti/cpts.c
+++ b/drivers/net/ethernet/ti/cpts.c
@@ -23,15 +23,13 @@
#define CPTS_SKB_TX_WORK_TIMEOUT 1 /* jiffies */

struct cpts_skb_cb_data {
+ u32 skb_mtype_seqid;
unsigned long tmo;
};

#define cpts_read32(c, r) readl_relaxed(&c->reg->r)
#define cpts_write32(c, v, r) writel_relaxed(v, &c->reg->r)

-static int cpts_match(struct sk_buff *skb, unsigned int ptp_class,
- u16 ts_seqid, u8 ts_msgtype);
-
static int event_expired(struct cpts_event *event)
{
return time_after(jiffies, event->tmo);
@@ -97,29 +95,29 @@ static void cpts_purge_txq(struct cpts *cpts)
static bool cpts_match_tx_ts(struct cpts *cpts, struct cpts_event *event)
{
struct sk_buff *skb, *tmp;
- u16 seqid;
- u8 mtype;
bool found = false;
+ u32 mtype_seqid;

- mtype = (event->high >> MESSAGE_TYPE_SHIFT) & MESSAGE_TYPE_MASK;
- seqid = (event->high >> SEQUENCE_ID_SHIFT) & SEQUENCE_ID_MASK;
+ mtype_seqid = event->high &
+ ((MESSAGE_TYPE_MASK << MESSAGE_TYPE_SHIFT) |
+ (SEQUENCE_ID_MASK << SEQUENCE_ID_SHIFT) |
+ (EVENT_TYPE_MASK << EVENT_TYPE_SHIFT));

/* no need to grab txq.lock as access is always done under cpts->lock */
skb_queue_walk_safe(&cpts->txq, skb, tmp) {
struct skb_shared_hwtstamps ssh;
- unsigned int class = ptp_classify_raw(skb);
struct cpts_skb_cb_data *skb_cb =
(struct cpts_skb_cb_data *)skb->cb;

- if (cpts_match(skb, class, seqid, mtype)) {
+ if (mtype_seqid == skb_cb->skb_mtype_seqid) {
memset(&ssh, 0, sizeof(ssh));
ssh.hwtstamp = ns_to_ktime(event->timestamp);
skb_tstamp_tx(skb, &ssh);
found = true;
__skb_unlink(skb, &cpts->txq);
dev_consume_skb_any(skb);
- dev_dbg(cpts->dev, "match tx timestamp mtype %u seqid %04x\n",
- mtype, seqid);
+ dev_dbg(cpts->dev, "match tx timestamp mtype_seqid %08x\n",
+ mtype_seqid);
break;
}

@@ -338,12 +336,15 @@ static const struct ptp_clock_info cpts_info = {
.do_aux_work = cpts_overflow_check,
};

-static int cpts_match(struct sk_buff *skb, unsigned int ptp_class,
- u16 ts_seqid, u8 ts_msgtype)
+static int cpts_skb_get_mtype_seqid(struct sk_buff *skb, u32 *mtype_seqid)
{
- u16 *seqid;
- unsigned int offset = 0;
+ unsigned int ptp_class = ptp_classify_raw(skb);
u8 *msgtype, *data = skb->data;
+ unsigned int offset = 0;
+ u16 *seqid;
+
+ if (ptp_class == PTP_CLASS_NONE)
+ return 0;

if (ptp_class & PTP_CLASS_VLAN)
offset += VLAN_HLEN;
@@ -371,22 +372,20 @@ static int cpts_match(struct sk_buff *skb, unsigned int ptp_class,
msgtype = data + offset;

seqid = (u16 *)(data + offset + OFF_PTP_SEQUENCE_ID);
+ *mtype_seqid = (*msgtype & MESSAGE_TYPE_MASK) << MESSAGE_TYPE_SHIFT;
+ *mtype_seqid |= (ntohs(*seqid) & SEQUENCE_ID_MASK) << SEQUENCE_ID_SHIFT;

- return (ts_msgtype == (*msgtype & 0xf) && ts_seqid == ntohs(*seqid));
+ return 1;
}

-static u64 cpts_find_ts(struct cpts *cpts, struct sk_buff *skb, int ev_type)
+static u64 cpts_find_ts(struct cpts *cpts, struct sk_buff *skb,
+ int ev_type, u32 skb_mtype_seqid)
{
- u64 ns = 0;
- struct cpts_event *event;
struct list_head *this, *next;
- unsigned int class = ptp_classify_raw(skb);
+ struct cpts_event *event;
unsigned long flags;
- u16 seqid;
- u8 mtype;
-
- if (class == PTP_CLASS_NONE)
- return 0;
+ u32 mtype_seqid;
+ u64 ns = 0;

spin_lock_irqsave(&cpts->lock, flags);
cpts_fifo_read(cpts, -1);
@@ -397,10 +396,13 @@ static u64 cpts_find_ts(struct cpts *cpts, struct sk_buff *skb, int ev_type)
list_add(&event->list, &cpts->pool);
continue;
}
- mtype = (event->high >> MESSAGE_TYPE_SHIFT) & MESSAGE_TYPE_MASK;
- seqid = (event->high >> SEQUENCE_ID_SHIFT) & SEQUENCE_ID_MASK;
- if (ev_type == event_type(event) &&
- cpts_match(skb, class, seqid, mtype)) {
+
+ mtype_seqid = event->high &
+ ((MESSAGE_TYPE_MASK << MESSAGE_TYPE_SHIFT) |
+ (SEQUENCE_ID_MASK << SEQUENCE_ID_SHIFT) |
+ (EVENT_TYPE_MASK << EVENT_TYPE_SHIFT));
+
+ if (mtype_seqid == skb_mtype_seqid) {
ns = event->timestamp;
list_del_init(&event->list);
list_add(&event->list, &cpts->pool);
@@ -427,10 +429,21 @@ static u64 cpts_find_ts(struct cpts *cpts, struct sk_buff *skb, int ev_type)

void cpts_rx_timestamp(struct cpts *cpts, struct sk_buff *skb)
{
- u64 ns;
+ struct cpts_skb_cb_data *skb_cb = (struct cpts_skb_cb_data *)skb->cb;
struct skb_shared_hwtstamps *ssh;
+ int ret;
+ u64 ns;
+
+ ret = cpts_skb_get_mtype_seqid(skb, &skb_cb->skb_mtype_seqid);
+ if (!ret)
+ return;
+
+ skb_cb->skb_mtype_seqid |= (CPTS_EV_RX << EVENT_TYPE_SHIFT);

- ns = cpts_find_ts(cpts, skb, CPTS_EV_RX);
+ dev_dbg(cpts->dev, "%s mtype seqid %08x\n",
+ __func__, skb_cb->skb_mtype_seqid);
+
+ ns = cpts_find_ts(cpts, skb, CPTS_EV_RX, skb_cb->skb_mtype_seqid);
if (!ns)
return;
ssh = skb_hwtstamps(skb);
@@ -441,12 +454,24 @@ EXPORT_SYMBOL_GPL(cpts_rx_timestamp);

void cpts_tx_timestamp(struct cpts *cpts, struct sk_buff *skb)
{
- u64 ns;
+ struct cpts_skb_cb_data *skb_cb = (struct cpts_skb_cb_data *)skb->cb;
struct skb_shared_hwtstamps ssh;
+ int ret;
+ u64 ns;

if (!(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
return;
- ns = cpts_find_ts(cpts, skb, CPTS_EV_TX);
+
+ ret = cpts_skb_get_mtype_seqid(skb, &skb_cb->skb_mtype_seqid);
+ if (!ret)
+ return;
+
+ skb_cb->skb_mtype_seqid |= (CPTS_EV_TX << EVENT_TYPE_SHIFT);
+
+ dev_dbg(cpts->dev, "%s mtype seqid %08x\n",
+ __func__, skb_cb->skb_mtype_seqid);
+
+ ns = cpts_find_ts(cpts, skb, CPTS_EV_TX, skb_cb->skb_mtype_seqid);
if (!ns)
return;
memset(&ssh, 0, sizeof(ssh));
--
2.17.1