[PATCH net v2] igb: initialize PTP state before registering PHC

[Runyu Xiao]

igb_ptp_init() currently initializes the PTP lock, work items,
timestamp configuration, and timecounter after ptp_clock_register().
The PHC is published by that call, so PTP callbacks and timestamp
interrupts can run before those objects are ready.

Initialize the complete PTP state before registering the PHC. Skip the
setup when CONFIG_PTP_1588_CLOCK is disabled, since the PTP registration
helper is then a no-op. If PHC registration fails, cancel the work items
queued by igb_ptp_reset() or a timestamp interrupt before returning.

Fixes: b888c510f7b3 ("igb: Avoid starting unnecessary workqueues")
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/netdev/20260830154912.2712900-1-runyu.xiao@xxxxxxxxxx/
Assisted-by: LLM
Signed-off-by: Runyu Xiao <runyu.xiao@xxxxxxxxxx>

---
v2:
- Restore all PTP state initialization before PHC registration.
- Skip PTP setup when CONFIG_PTP_1588_CLOCK is disabled.
- Cancel both PTP work items when PHC registration fails.
---
 drivers/net/ethernet/intel/igb/igb_ptp.c | 31 +++++++++++++++---------
 1 file changed, 19 insertions(+), 12 deletions(-)

diff --git a/drivers/net/ethernet/intel/igb/igb_ptp.c b/drivers/net/ethernet/intel/igb/igb_ptp.c
index 638d8242b..1c5581451 100644
--- a/drivers/net/ethernet/intel/igb/igb_ptp.c
+++ b/drivers/net/ethernet/intel/igb/igb_ptp.c
@@ -1307,6 +1307,9 @@ void igb_ptp_init(struct igb_adapter *adapter)
 	struct e1000_hw *hw = &adapter->hw;
 	struct net_device *netdev = adapter->netdev;
 
+	if (!IS_ENABLED(CONFIG_PTP_1588_CLOCK))
+		return;
+
 	switch (hw->mac.type) {
 	case e1000_82576:
 		snprintf(adapter->ptp_caps.name, 16, "%pm", netdev->dev_addr);
@@ -1378,27 +1381,31 @@ void igb_ptp_init(struct igb_adapter *adapter)
 		return;
 	}
 
+	spin_lock_init(&adapter->tmreg_lock);
+	INIT_WORK(&adapter->ptp_tx_work, igb_ptp_tx_work);
+
+	if (adapter->ptp_flags & IGB_PTP_OVERFLOW_CHECK)
+		INIT_DELAYED_WORK(&adapter->ptp_overflow_work,
+				  igb_ptp_overflow_check);
+
+	adapter->tstamp_config.rx_filter = HWTSTAMP_FILTER_NONE;
+	adapter->tstamp_config.tx_type = HWTSTAMP_TX_OFF;
+
+	igb_ptp_reset(adapter);
+
 	adapter->ptp_clock = ptp_clock_register(&adapter->ptp_caps,
 						&adapter->pdev->dev);
 	if (IS_ERR(adapter->ptp_clock)) {
+		if (adapter->ptp_flags & IGB_PTP_OVERFLOW_CHECK)
+			cancel_delayed_work_sync(&adapter->ptp_overflow_work);
+		cancel_work_sync(&adapter->ptp_tx_work);
+
 		adapter->ptp_clock = NULL;
 		dev_err(&adapter->pdev->dev, "ptp_clock_register failed\n");
 	} else if (adapter->ptp_clock) {
 		dev_info(&adapter->pdev->dev, "added PHC on %s\n",
 			 adapter->netdev->name);
 		adapter->ptp_flags |= IGB_PTP_ENABLED;
-
-		spin_lock_init(&adapter->tmreg_lock);
-		INIT_WORK(&adapter->ptp_tx_work, igb_ptp_tx_work);
-
-		if (adapter->ptp_flags & IGB_PTP_OVERFLOW_CHECK)
-			INIT_DELAYED_WORK(&adapter->ptp_overflow_work,
-					  igb_ptp_overflow_check);
-
-		adapter->tstamp_config.rx_filter = HWTSTAMP_FILTER_NONE;
-		adapter->tstamp_config.tx_type = HWTSTAMP_TX_OFF;
-
-		igb_ptp_reset(adapter);
 	}
 }
 
-- 
2.34.1