Re: [PATCH] drivers/power/88pm860x_battery.c: use devm_request_threaded_irq

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On Sat, 5 Jan 2013, Anton Vorontsov wrote:

On Sat, Dec 08, 2012 at 06:16:35PM +0100, Julia Lawall wrote:
From: Julia Lawall <Julia.Lawall@xxxxxxx>

devm_request_threaded_irq requests and irq that is freed when a driver
detaches.  This patch uses devm_request_threaded_irq for irqs that are
requested in the probe function of a platform device and are only freed in
the remove function.

Additionally, the original code used devm_kzalloc, but kfree.  This would
lead to a double free.  The problem was found using the following semantic
match (http://coccinelle.lip6.fr/):

// <smpl>
@@
expression x,e;
@@
x = devm_kzalloc(...)
... when != x = e
?-kfree(x,...);
// </smpl>

The error handling code in the probe function is also simplified in the
cases where there is now nothing to do other than return.

Signed-off-by: Julia Lawall <Julia.Lawall@xxxxxxx>

---
[....]
@@ -994,9 +989,6 @@ static int pm860x_battery_remove(struct platform_device *pdev)
 	struct pm860x_battery_info *info = platform_get_drvdata(pdev);

 	power_supply_unregister(&info->battery);
-	free_irq(info->irq_batt, info);
-	free_irq(info->irq_cc, info);
-	kfree(info);

It is not safe to access battery ('struct power_supply') object after
_unregister() (and irq handlers will surely do). Instead of removing
free_irq(), the right fix would be to place the two calls before
_unregister().

Thanks for the feedback.  I will send a new patch.

julia
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