qede: Handle infinite driver spinning for Tx timestamp.

In PTP Tx implementation, driver kept scheduling a poll thread until the
timestamp is available. In the error scenarios (e.g. app requesting the
timestamp for non-ptp packet), this thread kept waiting for the timestamp
forever.  This patch add changes to report such scenario as an error and
terminate the thread. Added a timeout of 2 seconds i.e., max time to wait
for Tx timestamp. Added a stat value ptp_skip_txts for reporting the number
of packets for which Tx timestamping is skipped.

Signed-off-by: Sudarsana Reddy Kalluru <skalluru@marvell.com>
Signed-off-by: Michal Kalderon <mkalderon@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/qlogic/qede/qede.h b/drivers/net/ethernet/qlogic/qede/qede.h
index 92fe226..b972ab0 100644 (file)
--- a/drivers/net/ethernet/qlogic/qede/qede.h
+++ b/drivers/net/ethernet/qlogic/qede/qede.h
@@ -92,6 +92,7 @@ struct qede_stats_common {
        u64 non_coalesced_pkts;
        u64 coalesced_bytes;
        u64 link_change_count;
+       u64 ptp_skip_txts;
 
        /* port */
        u64 rx_64_byte_packets;
@@ -189,6 +190,7 @@ struct qede_dev {
 
        const struct qed_eth_ops        *ops;
        struct qede_ptp                 *ptp;
+       u64                             ptp_skip_txts;
 
        struct qed_dev_eth_info dev_info;
 #define QEDE_MAX_RSS_CNT(edev) ((edev)->dev_info.num_queues)

diff --git a/drivers/net/ethernet/qlogic/qede/qede_ethtool.c b/drivers/net/ethernet/qlogic/qede/qede_ethtool.c
index 8911a97..e85f9fe 100644 (file)
--- a/drivers/net/ethernet/qlogic/qede/qede_ethtool.c
+++ b/drivers/net/ethernet/qlogic/qede/qede_ethtool.c
@@ -174,6 +174,7 @@ static const struct {
        QEDE_STAT(coalesced_bytes),
 
        QEDE_STAT(link_change_count),
+       QEDE_STAT(ptp_skip_txts),
 };
 
 #define QEDE_NUM_STATS ARRAY_SIZE(qede_stats_arr)

diff --git a/drivers/net/ethernet/qlogic/qede/qede_main.c b/drivers/net/ethernet/qlogic/qede/qede_main.c
index a9684a8..741377b 100644 (file)
--- a/drivers/net/ethernet/qlogic/qede/qede_main.c
+++ b/drivers/net/ethernet/qlogic/qede/qede_main.c
@@ -390,6 +390,7 @@ void qede_fill_by_demand_stats(struct qede_dev *edev)
        p_common->brb_discards = stats.common.brb_discards;
        p_common->tx_mac_ctrl_frames = stats.common.tx_mac_ctrl_frames;
        p_common->link_change_count = stats.common.link_change_count;
+       p_common->ptp_skip_txts = edev->ptp_skip_txts;
 
        if (QEDE_IS_BB(edev)) {
                struct qede_stats_bb *p_bb = &edev->stats.bb;
@@ -2232,6 +2233,8 @@ out:
        if (mode != QEDE_UNLOAD_RECOVERY)
                DP_NOTICE(edev, "Link is down\n");
 
+       edev->ptp_skip_txts = 0;
+
        DP_INFO(edev, "Ending qede unload\n");
 }
 

diff --git a/drivers/net/ethernet/qlogic/qede/qede_ptp.c b/drivers/net/ethernet/qlogic/qede/qede_ptp.c
index bddb2b5..f815435 100644 (file)
--- a/drivers/net/ethernet/qlogic/qede/qede_ptp.c
+++ b/drivers/net/ethernet/qlogic/qede/qede_ptp.c
@@ -30,6 +30,7 @@
  * SOFTWARE.
  */
 #include "qede_ptp.h"
+#define QEDE_PTP_TX_TIMEOUT (2 * HZ)
 
 struct qede_ptp {
        const struct qed_eth_ptp_ops    *ops;
@@ -38,6 +39,7 @@ struct qede_ptp {
        struct timecounter              tc;
        struct ptp_clock                *clock;
        struct work_struct              work;
+       unsigned long                   ptp_tx_start;
        struct qede_dev                 *edev;
        struct sk_buff                  *tx_skb;
 
@@ -160,18 +162,30 @@ static void qede_ptp_task(struct work_struct *work)
        struct qede_dev *edev;
        struct qede_ptp *ptp;
        u64 timestamp, ns;
+       bool timedout;
        int rc;
 
        ptp = container_of(work, struct qede_ptp, work);
        edev = ptp->edev;
+       timedout = time_is_before_jiffies(ptp->ptp_tx_start +
+                                         QEDE_PTP_TX_TIMEOUT);
 
        /* Read Tx timestamp registers */
        spin_lock_bh(&ptp->lock);
        rc = ptp->ops->read_tx_ts(edev->cdev, &timestamp);
        spin_unlock_bh(&ptp->lock);
        if (rc) {
-               /* Reschedule to keep checking for a valid timestamp value */
-               schedule_work(&ptp->work);
+               if (unlikely(timedout)) {
+                       DP_INFO(edev, "Tx timestamp is not recorded\n");
+                       dev_kfree_skb_any(ptp->tx_skb);
+                       ptp->tx_skb = NULL;
+                       clear_bit_unlock(QEDE_FLAGS_PTP_TX_IN_PRORGESS,
+                                        &edev->flags);
+                       edev->ptp_skip_txts++;
+               } else {
+                       /* Reschedule to keep checking for a valid TS value */
+                       schedule_work(&ptp->work);
+               }
                return;
        }
 
@@ -514,19 +528,28 @@ void qede_ptp_tx_ts(struct qede_dev *edev, struct sk_buff *skb)
        if (!ptp)
                return;
 
-       if (test_and_set_bit_lock(QEDE_FLAGS_PTP_TX_IN_PRORGESS, &edev->flags))
+       if (test_and_set_bit_lock(QEDE_FLAGS_PTP_TX_IN_PRORGESS,
+                                 &edev->flags)) {
+               DP_ERR(edev, "Timestamping in progress\n");
+               edev->ptp_skip_txts++;
                return;
+       }
 
        if (unlikely(!test_bit(QEDE_FLAGS_TX_TIMESTAMPING_EN, &edev->flags))) {
-               DP_NOTICE(edev,
-                         "Tx timestamping was not enabled, this packet will not be timestamped\n");
+               DP_ERR(edev,
+                      "Tx timestamping was not enabled, this packet will not be timestamped\n");
+               clear_bit_unlock(QEDE_FLAGS_PTP_TX_IN_PRORGESS, &edev->flags);
+               edev->ptp_skip_txts++;
        } else if (unlikely(ptp->tx_skb)) {
-               DP_NOTICE(edev,
-                         "The device supports only a single outstanding packet to timestamp, this packet will not be timestamped\n");
+               DP_ERR(edev,
+                      "The device supports only a single outstanding packet to timestamp, this packet will not be timestamped\n");
+               clear_bit_unlock(QEDE_FLAGS_PTP_TX_IN_PRORGESS, &edev->flags);
+               edev->ptp_skip_txts++;
        } else {
                skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
                /* schedule check for Tx timestamp */
                ptp->tx_skb = skb_get(skb);
+               ptp->ptp_tx_start = jiffies;
                schedule_work(&ptp->work);
        }
 }