Re: [PATCH 3/4] add ksm kernel shared memory driver

[Izik Eidus]

Jonathan Corbet wrote:
> On Wed, 12 Nov 2008 00:17:39 +0200
> Izik Eidus <ieidus@xxxxxxxxxx> wrote:
>
>   
> > > > +static int ksm_dev_open(struct inode *inode, struct file *filp)
> > > > +{
> > > > +	try_module_get(THIS_MODULE);
> > > > +	return 0;
> > > > +}
> > > > +
> > > > +static int ksm_dev_release(struct inode *inode, struct file *filp)
> > > > +{
> > > > +	module_put(THIS_MODULE);
> > > > +	return 0;
> > > > +}
> > > > +
> > > > +static struct file_operations ksm_chardev_ops = {
> > > > +	.open           = ksm_dev_open,
> > > > +	.release        = ksm_dev_release,
> > > > +	.unlocked_ioctl = ksm_dev_ioctl,
> > > > +	.compat_ioctl   = ksm_dev_ioctl,
> > > > +};
> > > >       
> > > >         
> > > Why do you roll your own module reference counting?  Is there a
> > > reason you don't just set .owner and let the VFS handle it?
> > >     
> > >       
> > Yes, I am taking get_task_mm() if the module will be removed before i 
> > free the mms, things will go wrong
> >     
>
> But...if you set .owner, the VFS will do the try_module_get() *before*
> calling into your module (as an added bonus, it will actually check the
> return value too).  
Ohhh i see what you mean
you are right i had at least needed to check for the return value of 
try_module_get(),
anyway will check this issue for V2.
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