Merge tag 'renesas-fixes3-for-v4.13' of https://git.kernel.org/pub/sc…

…m/linux/kernel/git/horms/renesas into fixes

Pull "Third Round of Renesas ARM Based SoC Fixes for v4.13" from Simon Horman:

Fix deadlock in regulator quirk for R-Car Gen 2 SoCs

The da9063/da9210 regulator quirk for R-Car Gen2 boards uses a bus
notifier, and unregisters the notifier when it is no longer needed.
However, a notifier must not be unregistered from within the call chain.

This bug went unnoticed, as blocking_notifier_chain_unregister() didn't
take the semaphore during early boot. This is no longer the case as of
upstream commit 1c3c5ea ("sched/core: Enable might_sleep() and
smp_processor_id() checks early") and a deadlock occurs.

* tag 'renesas-fixes3-for-v4.13' of https://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas:
  ARM: shmobile: rcar-gen2: Fix deadlock in regulator quirk

arch/arm/mach-shmobile/regulator-quirk-rcar-gen2.c

@@ -67,8 +67,12 @@ static int regulator_quirk_notify(struct notifier_block *nb,
 {
 	struct device *dev = data;
 	struct i2c_client *client;
+	static bool done;
 	u32 mon;
 
+	if (done)
+		return 0;
+
 	mon = ioread32(irqc + IRQC_MONITOR);
 	dev_dbg(dev, "%s: %ld, IRQC_MONITOR = 0x%x\n", __func__, action, mon);
 	if (mon & REGULATOR_IRQ_MASK)
@@ -99,7 +103,7 @@ static int regulator_quirk_notify(struct notifier_block *nb,
 remove:
 	dev_info(dev, "IRQ2 is not asserted, removing quirk\n");
 
-	bus_unregister_notifier(&i2c_bus_type, nb);
+	done = true;
 	iounmap(irqc);
 	return 0;
 }