Re: Linux 2.6.16-rc3

Russell King
2006-02-16T18:09:39Z

On Thu, Feb 16, 2006 at 09:57:32AM -0800, James Bottomley wrote:
> On Thu, 2006-02-16 at 17:12 +0000, Russell King wrote:
> > This is probably an idiotic question, but if there's something in the
> > scsi release handler can't be called in non-process context, why can't
> > scsi queue up the release processing via the work API itself, rather
> > than having to have this additional code and complexity for everyone?
>
> It's because, in order to get a guaranteed single allocation for the
> workqueue to execute in user context, I need to know when the release
> will be called. The only way to do that is to add the execute in
> process context directly to kref_put.

Is there something in the driver model which would prevent something
like this?

static void scsi_release_process(void *p)
{
struct my_work *work = p;
struct device *dev = work->dev;

/* destroy dev */

kfree(work);
}

static void scsi_release(struct device *dev)
{
struct my_work *work;

work = kmalloc(sizeof(struct my_work), GFP_ATOMIC);
if (work) {
INIT_WORK(&work->work, scsi_release_process, work);
work->dev = dev;
schedule_work(&work->work);
} else {
printk(KERN_ERR ...);
}
}

where scsi_release() is the function called by the device model on the
last put of a scsi device.

I guess is more or less what you're trying to do invasively via the
driver model.

--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of: 2.6 Serial core