[PATCH net v2 04/14] net: pse-pd: do not keep a failed IRQ in pcdev->irq

[Carlo Szelinsky <github@szelinsky.de>]

devm_pse_irq_helper() keeps the IRQ number in pcdev->irq even when the
IRQ request failed. The failed probe then runs
pse_controller_unregister(), which calls disable_irq() on that line. If
another device owns it, that device stops getting interrupts.

Clear pcdev->irq when the request fails. It is now set before the
request, because pse_isr() can run as soon as the IRQ is enabled and
pse_pw_d_is_sw_pw_control() reads it.

Found by code inspection. Not reproduced.

Fixes: ffef61d6d273 ("net: pse-pd: Add support for budget evaluation strategies")
Reviewed-by: Kory Maincent <kory.maincent@bootlin.com>
Signed-off-by: Carlo Szelinsky <github@szelinsky.de>
---
 drivers/net/pse-pd/pse_core.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/net/pse-pd/pse_core.c b/drivers/net/pse-pd/pse_core.c
index c6612232b820..eab7e25f2039 100644
--- a/drivers/net/pse-pd/pse_core.c
+++ b/drivers/net/pse-pd/pse_core.c
@@ -1343,14 +1343,20 @@ int devm_pse_irq_helper(struct pse_controller_dev *pcdev, int irq,
 	if (!h->notifs_mask)
 		return -ENOMEM;
 
+	/* pse_isr() can run as soon as the IRQ is enabled, and
+	 * pse_pw_d_is_sw_pw_control() reads pcdev->irq.
+	 */
+	pcdev->irq = irq;
 	ret = devm_request_threaded_irq(dev, irq, NULL, pse_isr,
 					IRQF_ONESHOT | irq_flags,
 					irq_name, h);
-	if (ret)
+	if (ret) {
+		pcdev->irq = 0;
 		dev_err(pcdev->dev, "Failed to request IRQ %d\n", irq);
+		return ret;
+	}
 
-	pcdev->irq = irq;
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL_GPL(devm_pse_irq_helper);
 
-- 
2.43.0