[PATCH net-next] net: ti: icssm-prueth: use dev_close()/dev_open() in icssm_prueth_change_mode()

[Sai Varun Mudepally]

In icssm_prueth_change_mode(), if ndev->netdev_ops->ndo_open(ndev) fails
and returns an error, the function aborts without restoring the NAPI state.
Later, when the interface is brought down, the kernel naturally invokes
ndo_stop() again. A second napi_disable() call on an already disabled NAPI
might trigger an infinite sleep waiting for NAPI_STATE_SCHED.

Use dev_close()/dev_open() so the core keeps IFF_UP consistent. If
dev_open() fails, close the ports already reopened and fall back to
EMAC mode.

Also undo the br_members update in icssm_prueth_ndev_port_link() when
icssm_prueth_port_offload_fwd_mark_update() fails.

Test Log:
https://gist.github.com/SaiVarun754/688a21038f1b2bd2b89d2db65224edb0

Fixes: eca327ae9aa6 ("net: ti: icssm-prueth: Add support for ICSSM RSTP switch")
Signed-off-by: Sai Varun Mudepally <saivarun@xxxxxxxxxxx>
---
 drivers/net/ethernet/ti/icssm/icssm_prueth.c | 38 ++++++++++++++------
 1 file changed, 28 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/ti/icssm/icssm_prueth.c b/drivers/net/ethernet/ti/icssm/icssm_prueth.c
index b42c98e861e0..d50aa0992c33 100644
--- a/drivers/net/ethernet/ti/icssm/icssm_prueth.c
+++ b/drivers/net/ethernet/ti/icssm/icssm_prueth.c
@@ -1100,7 +1100,7 @@ static int icssm_prueth_change_mode(struct prueth *prueth,
 	bool portstatus[PRUETH_NUM_MACS];
 	struct prueth_emac *emac;
 	struct net_device *ndev;
-	int i, ret;
+	int i, j, ret;
 
 	for (i = 0; i < PRUETH_NUM_MACS; i++) {
 		if (!prueth->emac[i]) {
@@ -1115,11 +1115,7 @@ static int icssm_prueth_change_mode(struct prueth *prueth,
 		if (!portstatus[i])
 			continue;
 
-		ret = ndev->netdev_ops->ndo_stop(ndev);
-		if (ret < 0) {
-			netdev_err(ndev, "failed to stop: %d", ret);
-			return ret;
-		}
+		dev_close(ndev);
 	}
 
 	if (mode == PRUSS_ETHTYPE_EMAC || mode == PRUSS_ETHTYPE_SWITCH) {
@@ -1141,14 +1137,25 @@ static int icssm_prueth_change_mode(struct prueth *prueth,
 		if (!portstatus[i])
 			continue;
 
-		ret = ndev->netdev_ops->ndo_open(ndev);
+		ret = dev_open(ndev, NULL);
 		if (ret < 0) {
 			netdev_err(ndev, "failed to start: %d", ret);
-			return ret;
+			goto err_dev_open;
 		}
 	}
 
 	return 0;
+
+err_dev_open:
+	for (j = 0; j < i; j++) {
+		if (portstatus[j])
+			dev_close(prueth->emac[j]->ndev);
+	}
+
+	/* Fall back to EMAC mode */
+	prueth->eth_type = PRUSS_ETHTYPE_EMAC;
+
+	return ret;
 }
 
 /* VLAN-tag PCP to priority queue map for EMAC/Switch/HSR/PRP used by driver
@@ -1639,6 +1646,8 @@ bool icssm_prueth_sw_port_dev_check(const struct net_device *ndev)
 
 static int icssm_prueth_port_offload_fwd_mark_update(struct prueth *prueth)
 {
+	struct prueth_emac *emac;
+	unsigned long flags;
 	int set_val = 0;
 	int i, ret = 0;
 	u8 all_slaves;
@@ -1661,11 +1670,20 @@ static int icssm_prueth_port_offload_fwd_mark_update(struct prueth *prueth)
 	 */
 	if (set_val && !PRUETH_IS_SWITCH(prueth)) {
 		ret = icssm_prueth_change_mode(prueth, PRUSS_ETHTYPE_SWITCH);
-		if (ret < 0)
+		if (ret < 0) {
 			dev_err(prueth->dev, "Failed to enable Switch mode\n");
-		else
+			emac = prueth->emac[0];
+			spin_lock_irqsave(&emac->addr_lock, flags);
+
+			prueth->br_members &= ~BIT(emac->port_id);
+			if (!prueth->br_members)
+				prueth->hw_bridge_dev = NULL;
+
+			spin_unlock_irqrestore(&emac->addr_lock, flags);
+		} else {
 			dev_info(prueth->dev,
 				 "TI PRU ethernet now in Switch mode\n");
+		}
 	}
 
 	/* Bridge is deleted, switch to Dual EMAC mode */
-- 
2.43.0