Re: SCSI RAM driver ported to 3.3 kernel for file system and I/Otesting

From: Matthew Wilcox
Date: Wed May 16 2012 - 15:34:07 EST


On Wed, May 16, 2012 at 03:31:55PM -0400, chetan loke wrote:
> > +               if (list_empty(&ram_device->commands))
> > +                       wake_up_process(ram_device->thread);
>
> Didn't look in detail but if the queue is empty then why would you
> want to wake up the kthread? What if you just wake_up after
> list_add_tail below?

If the list is non-empty, then the kthread has already been woken up
and doesn't need to be woken again.

> > +               list_add_tail(&ram_cmnd->queue, &ram_device->commands);
> > +               spin_unlock_irqrestore(shost->host_lock, flags);
> > +       } else {
> > +               scsi_ram_execute_command(cmnd);
> > +       }
>
>
> Chetan Loke
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