Hi Robert, On Sat, May 28, 2011 at 5:15 PM, Robert P. J. Day <rpjday@crashcourse.ca> wrote:
from 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) { device_initialize(dev); return device_add(dev); }
and yet, there appears to be driver code that does exactly that, such as this snippet from drivers/w1/w1_int.c (line 86):
... snip ... err = device_register(&dev->dev); if (err) { printk(KERN_ERR "Failed to register master device. err=%d\n", err); memset(dev, 0, sizeof(struct w1_master)); kfree(dev); dev = NULL; }
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; }
return dev;
isn't the above doing just that -- directly freeing the dev structure without first calling put_device()? or am i misreading something?
rday
--
======================================================================== Robert P. J. Day Ottawa, Ontario, CANADA http://crashcourse.ca
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