clocksource/drivers/davinci: Fix memory leak in davinci_timer_register when init fails

Smatch reports:
drivers/clocksource/timer-davinci.c:332 davinci_timer_register()
warn: 'base' from ioremap() not released on lines: 274.

Fix this and other potential memory leak problems
by adding a set of corresponding exit lables.

Fixes: 721154f972 ("clocksource/drivers/davinci: Add support for clockevents")
Signed-off-by: Qinrun Dai <flno@hust.edu.cn>
Link: https://lore.kernel.org/r/20230413135037.1505799-1-flno@hust.edu.cn
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

drivers/clocksource/timer-davinci.c

@@ -257,21 +257,25 @@ int __init davinci_timer_register(struct clk *clk,
 				resource_size(&timer_cfg->reg),
 				"davinci-timer")) {
 		pr_err("Unable to request memory region\n");
-		return -EBUSY;
+		rv = -EBUSY;
+		goto exit_clk_disable;
 	}
 
 	base = ioremap(timer_cfg->reg.start, resource_size(&timer_cfg->reg));
 	if (!base) {
 		pr_err("Unable to map the register range\n");
-		return -ENOMEM;
+		rv = -ENOMEM;
+		goto exit_mem_region;
 	}
 
 	davinci_timer_init(base);
 	tick_rate = clk_get_rate(clk);
 
 	clockevent = kzalloc(sizeof(*clockevent), GFP_KERNEL);
-	if (!clockevent)
-		return -ENOMEM;
+	if (!clockevent) {
+		rv = -ENOMEM;
+		goto exit_iounmap_base;
+	}
 
 	clockevent->dev.name = "tim12";
 	clockevent->dev.features = CLOCK_EVT_FEAT_ONESHOT;
@@ -296,7 +300,7 @@ int __init davinci_timer_register(struct clk *clk,
 			 "clockevent/tim12", clockevent);
 	if (rv) {
 		pr_err("Unable to request the clockevent interrupt\n");
-		return rv;
+		goto exit_free_clockevent;
 	}
 
 	davinci_clocksource.dev.rating = 300;
@@ -323,13 +327,27 @@ int __init davinci_timer_register(struct clk *clk,
 	rv = clocksource_register_hz(&davinci_clocksource.dev, tick_rate);
 	if (rv) {
 		pr_err("Unable to register clocksource\n");
-		return rv;
+		goto exit_free_irq;
 	}
 
 	sched_clock_register(davinci_timer_read_sched_clock,
 			     DAVINCI_TIMER_CLKSRC_BITS, tick_rate);
 
 	return 0;
+
+exit_free_irq:
+	free_irq(timer_cfg->irq[DAVINCI_TIMER_CLOCKEVENT_IRQ].start,
+			clockevent);
+exit_free_clockevent:
+	kfree(clockevent);
+exit_iounmap_base:
+	iounmap(base);
+exit_mem_region:
+	release_mem_region(timer_cfg->reg.start,
+			   resource_size(&timer_cfg->reg));
+exit_clk_disable:
+	clk_disable_unprepare(clk);
+	return rv;
 }
 
 static int __init of_davinci_timer_register(struct device_node *np)