Re: dmfs for 2.5.51

Greg KH (greg@kroah.com)
Thu, 12 Dec 2002 21:25:51 -0800


On Thu, Dec 12, 2002 at 05:50:01PM -0800, Andrew Morton wrote:
> Greg KH wrote:
> >
> > ..
> > +Examples
> > +--------
> > +
> > +Example commands will make things a bit clearer:
>
> hm. The whole thing seems hokey to me. Not sure why.

I agree. It doesn't feel right. I mean, doing a mkdir(1) to create a
device, which causes files to be created automagically in that
directory? Something needs to change here, and I proposed a single file
to write to that creates the device, but was shot down by the author.

Anyone else have any ideas?

> > ...
> > + echo -e "0 56 linear /dev/hda3 0\n56 102344 linear /dev/hda4 0" > table
>
> Maybe this is why.

Heh, yeah, welcome to parsers in the kernel :)
But the dm code today does much the same thing with ioctls, passing a
string down to the loaded modules below it. So there is a bit of
president. Even if it is ugly :)

> > ...
> > +static struct page *find_page(struct dmfs_file *f, loff_t len, int fill)
>
> This is called under spinlock.
>
> > ...
> > + void *addr = (void *) __get_free_page(GFP_KERNEL);
>
> whoops.

Nice catch. I'm not sure that the find_page(), __io() and friends
functions are really needed at all.

Thanks for looking at this. I hope the dm authors can help explain
more.

greg k-h
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/