bnxt_en: Optimize recovery path ULP locking in the driver

In the error recovery path (AER, firmware recovery, etc), the
driver notifies the RoCE driver via ULP_STOP before the reset
and via ULP_START after the reset, all under RTNL_LOCK.  The
RoCE driver can take a long time if there are a lot of QPs to
destroy, so it is not ideal to hold the global RTNL lock.

Rely on the new en_dev_lock mutex instead for ULP_STOP and
ULP_START.  For the most part, we move the ULP_STOP call before
we take the RTNL lock and move the ULP_START after RTNL unlock.
Note that SRIOV re-enablement must be done after ULP_START
or RoCE on the VFs will not resume properly after reset.

The one scenario in bnxt_hwrm_if_change() where the RTNL lock
is already taken in the .ndo_open() context requires the ULP
restart to be deferred to the bnxt_sp_task() workqueue.

Reviewed-by: Selvin Thyparampil Xavier <selvin.xavier@broadcom.com>
Reviewed-by: Vikas Gupta <vikas.gupta@broadcom.com>
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240501003056.100607-6-michael.chan@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: Kalesh AP

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -11556,7 +11556,7 @@ static int bnxt_hwrm_if_change(struct bnxt *bp, bool up)
 		if (fw_reset) {
 			set_bit(BNXT_STATE_FW_RESET_DET, &bp->state);
 			if (!test_bit(BNXT_STATE_IN_FW_RESET, &bp->state))
-				bnxt_ulp_stop(bp);
+				bnxt_ulp_irq_stop(bp);
 			bnxt_free_ctx_mem(bp);
 			bnxt_dcb_free(bp);
 			rc = bnxt_fw_init_one(bp);
@@ -12111,10 +12111,9 @@ static int bnxt_open(struct net_device *dev)
 		bnxt_hwrm_if_change(bp, false);
 	} else {
 		if (test_and_clear_bit(BNXT_STATE_FW_RESET_DET, &bp->state)) {
-			if (!test_bit(BNXT_STATE_IN_FW_RESET, &bp->state)) {
-				bnxt_ulp_start(bp, 0);
-				bnxt_reenable_sriov(bp);
-			}
+			if (!test_bit(BNXT_STATE_IN_FW_RESET, &bp->state))
+				bnxt_queue_sp_work(bp,
+						   BNXT_RESTART_ULP_SP_EVENT);
 		}
 	}
 
@@ -13270,7 +13269,6 @@ static void bnxt_fw_fatal_close(struct bnxt *bp)
 
 static void bnxt_fw_reset_close(struct bnxt *bp)
 {
-	bnxt_ulp_stop(bp);
 	/* When firmware is in fatal state, quiesce device and disable
 	 * bus master to prevent any potential bad DMAs before freeing
 	 * kernel memory.
@@ -13351,6 +13349,7 @@ void bnxt_fw_exception(struct bnxt *bp)
 {
 	netdev_warn(bp->dev, "Detected firmware fatal condition, initiating reset\n");
 	set_bit(BNXT_STATE_FW_FATAL_COND, &bp->state);
+	bnxt_ulp_stop(bp);
 	bnxt_rtnl_lock_sp(bp);
 	bnxt_force_fw_reset(bp);
 	bnxt_rtnl_unlock_sp(bp);
@@ -13382,6 +13381,7 @@ static int bnxt_get_registered_vfs(struct bnxt *bp)
 
 void bnxt_fw_reset(struct bnxt *bp)
 {
+	bnxt_ulp_stop(bp);
 	bnxt_rtnl_lock_sp(bp);
 	if (test_bit(BNXT_STATE_OPEN, &bp->state) &&
 	    !test_bit(BNXT_STATE_IN_FW_RESET, &bp->state)) {
@@ -13506,6 +13506,12 @@ static void bnxt_fw_echo_reply(struct bnxt *bp)
 	hwrm_req_send(bp, req);
 }
 
+static void bnxt_ulp_restart(struct bnxt *bp)
+{
+	bnxt_ulp_stop(bp);
+	bnxt_ulp_start(bp, 0);
+}
+
 static void bnxt_sp_task(struct work_struct *work)
 {
 	struct bnxt *bp = container_of(work, struct bnxt, sp_task);
@@ -13517,6 +13523,11 @@ static void bnxt_sp_task(struct work_struct *work)
 		return;
 	}
 
+	if (test_and_clear_bit(BNXT_RESTART_ULP_SP_EVENT, &bp->sp_event)) {
+		bnxt_ulp_restart(bp);
+		bnxt_reenable_sriov(bp);
+	}
+
 	if (test_and_clear_bit(BNXT_RX_MASK_SP_EVENT, &bp->sp_event))
 		bnxt_cfg_rx_mode(bp);
 
@@ -13973,10 +13984,8 @@ static bool bnxt_fw_reset_timeout(struct bnxt *bp)
 static void bnxt_fw_reset_abort(struct bnxt *bp, int rc)
 {
 	clear_bit(BNXT_STATE_IN_FW_RESET, &bp->state);
-	if (bp->fw_reset_state != BNXT_FW_RESET_STATE_POLL_VF) {
-		bnxt_ulp_start(bp, rc);
+	if (bp->fw_reset_state != BNXT_FW_RESET_STATE_POLL_VF)
 		bnxt_dl_health_fw_status_update(bp, false);
-	}
 	bp->fw_reset_state = 0;
 	dev_close(bp->dev);
 }
@@ -14007,7 +14016,7 @@ static void bnxt_fw_reset_task(struct work_struct *work)
 				bp->fw_reset_state = 0;
 				netdev_err(bp->dev, "Firmware reset aborted, bnxt_get_registered_vfs() returns %d\n",
 					   n);
-				return;
+				goto ulp_start;
 			}
 			bnxt_queue_fw_reset_work(bp, HZ / 10);
 			return;
@@ -14017,7 +14026,7 @@ static void bnxt_fw_reset_task(struct work_struct *work)
 		if (test_bit(BNXT_STATE_ABORT_ERR, &bp->state)) {
 			bnxt_fw_reset_abort(bp, rc);
 			rtnl_unlock();
-			return;
+			goto ulp_start;
 		}
 		bnxt_fw_reset_close(bp);
 		if (bp->fw_cap & BNXT_FW_CAP_ERR_RECOVER_RELOAD) {
@@ -14110,7 +14119,7 @@ static void bnxt_fw_reset_task(struct work_struct *work)
 			netdev_err(bp->dev, "bnxt_open() failed during FW reset\n");
 			bnxt_fw_reset_abort(bp, rc);
 			rtnl_unlock();
-			return;
+			goto ulp_start;
 		}
 
 		if ((bp->fw_cap & BNXT_FW_CAP_ERROR_RECOVERY) &&
@@ -14122,17 +14131,19 @@ static void bnxt_fw_reset_task(struct work_struct *work)
 		/* Make sure fw_reset_state is 0 before clearing the flag */
 		smp_mb__before_atomic();
 		clear_bit(BNXT_STATE_IN_FW_RESET, &bp->state);
-		bnxt_ulp_start(bp, 0);
-		bnxt_reenable_sriov(bp);
-		bnxt_vf_reps_alloc(bp);
-		bnxt_vf_reps_open(bp);
 		bnxt_ptp_reapply_pps(bp);
 		clear_bit(BNXT_STATE_FW_ACTIVATE, &bp->state);
 		if (test_and_clear_bit(BNXT_STATE_RECOVER, &bp->state)) {
 			bnxt_dl_health_fw_recovery_done(bp);
 			bnxt_dl_health_fw_status_update(bp, true);
 		}
 		rtnl_unlock();
+		bnxt_ulp_start(bp, 0);
+		bnxt_reenable_sriov(bp);
+		rtnl_lock();
+		bnxt_vf_reps_alloc(bp);
+		bnxt_vf_reps_open(bp);
+		rtnl_unlock();
 		break;
 	}
 	return;
@@ -14148,6 +14159,8 @@ static void bnxt_fw_reset_task(struct work_struct *work)
 	rtnl_lock();
 	bnxt_fw_reset_abort(bp, rc);
 	rtnl_unlock();
+ulp_start:
+	bnxt_ulp_start(bp, rc);
 }
 
 static int bnxt_init_board(struct pci_dev *pdev, struct net_device *dev)
@@ -15534,8 +15547,9 @@ static int bnxt_suspend(struct device *device)
 	struct bnxt *bp = netdev_priv(dev);
 	int rc = 0;
 
-	rtnl_lock();
 	bnxt_ulp_stop(bp);
+
+	rtnl_lock();
 	if (netif_running(dev)) {
 		netif_device_detach(dev);
 		rc = bnxt_close(dev);
@@ -15590,10 +15604,10 @@ static int bnxt_resume(struct device *device)
 	}
 
 resume_exit:
+	rtnl_unlock();
 	bnxt_ulp_start(bp, rc);
 	if (!rc)
 		bnxt_reenable_sriov(bp);
-	rtnl_unlock();
 	return rc;
 }
 
@@ -15623,11 +15637,11 @@ static pci_ers_result_t bnxt_io_error_detected(struct pci_dev *pdev,
 
 	netdev_info(netdev, "PCI I/O error detected\n");
 
+	bnxt_ulp_stop(bp);
+
 	rtnl_lock();
 	netif_device_detach(netdev);
 
-	bnxt_ulp_stop(bp);
-
 	if (test_and_set_bit(BNXT_STATE_IN_FW_RESET, &bp->state)) {
 		netdev_err(bp->dev, "Firmware reset already in progress\n");
 		abort = true;
@@ -15763,13 +15777,13 @@ static void bnxt_io_resume(struct pci_dev *pdev)
 	if (!err && netif_running(netdev))
 		err = bnxt_open(netdev);
 
-	bnxt_ulp_start(bp, err);
-	if (!err) {
-		bnxt_reenable_sriov(bp);
+	if (!err)
 		netif_device_attach(netdev);
-	}
 
 	rtnl_unlock();
+	bnxt_ulp_start(bp, err);
+	if (!err)
+		bnxt_reenable_sriov(bp);
 }
 
 static const struct pci_error_handlers bnxt_err_handler = {

drivers/net/ethernet/broadcom/bnxt/bnxt.h

@@ -2440,6 +2440,7 @@ struct bnxt {
 #define BNXT_LINK_CFG_CHANGE_SP_EVENT	21
 #define BNXT_THERMAL_THRESHOLD_SP_EVENT	22
 #define BNXT_FW_ECHO_REQUEST_SP_EVENT	23
+#define BNXT_RESTART_ULP_SP_EVENT	24
 
 	struct delayed_work	fw_reset_task;
 	int			fw_reset_state;

drivers/net/ethernet/broadcom/bnxt/bnxt_devlink.c

@@ -437,18 +437,20 @@ static int bnxt_dl_reload_down(struct devlink *dl, bool netns_change,
 
 	switch (action) {
 	case DEVLINK_RELOAD_ACTION_DRIVER_REINIT: {
+		bnxt_ulp_stop(bp);
 		rtnl_lock();
 		if (bnxt_sriov_cfg(bp)) {
 			NL_SET_ERR_MSG_MOD(extack,
 					   "reload is unsupported while VFs are allocated or being configured");
 			rtnl_unlock();
+			bnxt_ulp_start(bp, 0);
 			return -EOPNOTSUPP;
 		}
 		if (bp->dev->reg_state == NETREG_UNREGISTERED) {
 			rtnl_unlock();
+			bnxt_ulp_start(bp, 0);
 			return -ENODEV;
 		}
-		bnxt_ulp_stop(bp);
 		if (netif_running(bp->dev))
 			bnxt_close_nic(bp, true, true);
 		bnxt_vf_reps_free(bp);
@@ -516,7 +518,6 @@ static int bnxt_dl_reload_up(struct devlink *dl, enum devlink_reload_action acti
 		bnxt_vf_reps_alloc(bp);
 		if (netif_running(bp->dev))
 			rc = bnxt_open_nic(bp, true, true);
-		bnxt_ulp_start(bp, rc);
 		if (!rc) {
 			bnxt_reenable_sriov(bp);
 			bnxt_ptp_reapply_pps(bp);
@@ -570,6 +571,8 @@ static int bnxt_dl_reload_up(struct devlink *dl, enum devlink_reload_action acti
 		dev_close(bp->dev);
 	}
 	rtnl_unlock();
+	if (action == DEVLINK_RELOAD_ACTION_DRIVER_REINIT)
+		bnxt_ulp_start(bp, rc);
 	return rc;
 }