Hi Robert,
On Sat, May 28, 2011 at 5:15 PM, Robert P. J. Day <rpjday@xxxxxxxxxxxxxx> wrote:
>
> Âfrom drivers/base/core.c, we have the fairly unambiguous advice:
>
> * NOTE: _Never_ directly free @dev after calling this function, even
> * if it returned an error! Always use put_device() to give up the
> * reference initialized in this function instead.
> */
> int device_register(struct device *dev)
> {
> Â Â Â Âdevice_initialize(dev);
> Â Â Â Âreturn device_add(dev);
> }
>
> Âand yet, there appears to be driver code that does exactly that,
> such as this snippet from drivers/w1/w1_int.c (line 86):
>
> Â Â Â Â... snip ...
> Â Â Â Âerr = device_register(&dev->dev);
> Â Â Â Âif (err) {
> Â Â Â Â Â Â Â Âprintk(KERN_ERR "Failed to register master device. err=%d\n", err);
> Â Â Â Â Â Â Â Âmemset(dev, 0, sizeof(struct w1_master));
> Â Â Â Â Â Â Â Âkfree(dev);
> Â Â Â Â Â Â Â Âdev = NULL;
> Â Â Â Â}
Free is for allocated dev not for struct device so it is OK. IMO thi
snippet should look like:
err = device_register(&dev->dev);
if (err) {
printk(KERN_ERR "Failed to register master device. err=%d\n", err);
put_device(&dev->dev);
memset(dev, 0, sizeof(struct w1_master));
kfree(dev);
dev = NULL;
}
>
> Â Â Â Âreturn dev;
>
> Âisn't the above doing just that -- directly freeing the dev
> structure without first calling put_device()? Âor am i misreading
> something?
>
> rday
>
> --
>
> ========================================================================
> Robert P. J. Day                 Ottawa, Ontario, CANADA
> Â Â Â Â Â Â Â Â Â Â Â Âhttp://crashcourse.ca
>
> Twitter: Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â http://twitter.com/rpjday
> LinkedIn: Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â http://ca.linkedin.com/in/rpjday
> ========================================================================
>
>
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regards,
marek
--
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Marek Belisko - OPEN-NANDRA
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