Re: Reading page from given block device

[Alexander Viro]

On Thu, 9 May 2002, Pavel Machek wrote:

> Hi!
> 
> > > Well, I'm doing it during boot, and this is swap partition; it should
> > > not have been accessed previously.
> > > 
> > > > >         bdev = bdget(kdev_t_to_nr(dev));
> > > > >         if (!bdev) {
> > > > >                 printk("No block device for %s\n", __bdevname(dev));
> > > > >                 BUG();
> > > > >         }
> > > > >         printk("C");
> > 
> > blkdev_open(bdev, FMODE_READ, O_RDONLY, BDEV_RAW)
> 
> blkdev_open is 

grr...  s/open/get/ - sorry.

> fs.h:extern int blkdev_open(struct inode *, struct file *);
> 
> ... I can't see how to use it in this context.
> 
> > > > >         if (!bh || (!bh->b_data)) {
> > > > >                 return -1;
> > 
> > However, I would really suggest to open the bugger once, do all IO and
> > then close it.  See how raw.c and friends deal with these problems.
> 
> Performance should not matter here.

Yeah, but amount of places that mess with kdev_t should.