Re: [PATCH 4/9] gpiolib: use gpio_chips list in sysfs ops

From: Alexandre Courbot
Date: Sat Feb 09 2013 - 08:53:47 EST

On Sat, Feb 9, 2013 at 6:37 PM, Grant Likely <grant.likely@xxxxxxxxxxxx> wrote:
> However, this code is incorrect (it was incorrect before you touched it,
> so not your fault). Moving it to a list makes it a lot worse though
> because it introduces the possibility of dereferencing an invalid
> pointer. The hooks need to grab the spinlock before parsing the list.
> I've got a patch which I'll post. I'd appreciate it if you can test
> also.
> In actual fact, I'd like to replace the spinlock with a mutex, but that
> requires some auditing to make sure there aren't any users from an
> atomic context.

I thought about doing that as well actually, but left it for later. It
looks safe at first sight, but as you mention we cannot exclude a few
users will break as a consequence of such a switch.

In any case, I plan to give it a try once that big chunk is merged.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at