Re: [PATCH] ipack: add missing put_device() after device_register()failed
From: Dmitry Torokhov
Date: Tue Feb 26 2013 - 17:29:01 EST
On Tue, Feb 26, 2013 at 10:03:15AM +0100, Samuel Iglesias Gonsalvez wrote:
> put_device() must be called after device_register() fails,
> since device_register() always initializes the refcount
> on the device structure to one.
> dev->id is free'd inside of ipack_device_release function.
> So, it's not needed to do it here.
> Signed-off-by: Samuel Iglesias Gonsalvez <siglesias@xxxxxxxxxx>
> drivers/ipack/ipack.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
> diff --git a/drivers/ipack/ipack.c b/drivers/ipack/ipack.c
> index 7ec6b20..3588ccf 100644
> --- a/drivers/ipack/ipack.c
> +++ b/drivers/ipack/ipack.c
> @@ -449,7 +449,7 @@ int ipack_device_register(struct ipack_device *dev)
> ret = device_register(&dev->dev);
> if (ret < 0)
> - kfree(dev->id);
> + put_device(&dev->dev);
Now callers have no idea if they have to free (put_device) it in case of
failure or it is already done for them, because a few lines earlier, if
pack_device_read_id() fails, it simply returns error code.
IMO if a function did not allocate object it should not try to free it,
callers should dispose of the device as they see fit.
What is missing, however, is dev->id = NULL assignment so that if caller
does put_device() kit won't double-free the memory. Also it would make
sense to split device_register into device_init() and device_add() so
that device_init() is very first thing you do and in case of all
failures callers should use put_device().
Also tpci200.c need to learn to clean up after itself and I also not
sure why it tries to provide its own release function.
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