Re: [RFC 22/22] tcm_loop: Add multi-fabric Linux/SCSI LLD fabricmodule

From: Greg KH
Date: Mon Sep 06 2010 - 01:16:29 EST


On Sun, Sep 05, 2010 at 10:08:16PM -0700, Dmitry Torokhov wrote:
> On Sun, Sep 05, 2010 at 02:51:19PM -0700, Nicholas A. Bellinger wrote:
> > On Sun, 2010-09-05 at 13:30 -0700, Dmitry Torokhov wrote:
> > > On Mon, Aug 30, 2010 at 02:23:23AM -0700, Nicholas A. Bellinger wrote:
> > > > +
> > > > +static void tcm_loop_primary_release(struct device *dev)
> > > > +{
> > > > + return;
> > > > +}
> > > > +
> > > > +static struct device tcm_loop_primary = {
> > > > + .init_name = "tcm_loop_0",
> > > > + .release = tcm_loop_primary_release,
> > > > +};
> > > > +
> > >
> > > No, you can not have statically allocated devices and dummy release
> > > functions.
> > >
> >
> > Last time I checked this is still what mainline
> > drivers/scsi/scsi_debug.c is doing for struct device pseudo_primary:
> >
> > static void pseudo_0_release(struct device *dev)
> > {
> > if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts)
> > printk(KERN_INFO "scsi_debug: pseudo_0_release() called\n");
> > }
> >
> > static struct device pseudo_primary = {
> > .init_name = "pseudo_0",
> > .release = pseudo_0_release,
> > };
> >
> > so for these type of things in TCM_Loop I tend to follow what scsi_debug does,
> > so I don't exactly see a issue here atm. Anybody else have comments..?
>
> The kobject embedded in the device structure is refcounted and it's
> lifetime may be different from lifetime of your module. If somebody
> happen to hold reference to the driver while your module is being
> unloaded bad things will happen.
>
> I am sure Greg has something on this topic ready for cut-and-paste.

Documentation/kobject.txt :)

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