Re: [PATCH] [LMB]: Fix lmb_add_region if region should be added at the head

[Kumar Gala]

On Feb 19, 2008, at 10:45 PM, David Miller wrote:

> From: Kumar Gala <galak@xxxxxxxxxxxxxxxxxxx>
> Date: Tue, 19 Feb 2008 22:27:48 -0600 (CST)
>
> > We introduced a bug in fixing lmb_add_region to handle an initial
> > region being non-zero.  Before that fix it was impossible to insert
> > a region at the head of the list since the first region always  
> > started
> > at zero.
> >
> > Now that its possible for the first region to be non-zero we need to
> > check to see if the new region should be added at the head and if so
> > actually add it.
> >
> > Signed-off-by: Kumar Gala <galak@xxxxxxxxxxxxxxxxxxx>
> ...
> > @@ -184,6 +184,11 @@ static long __init lmb_add_region(struct  
> > lmb_region *rgn, u64 base, u64 size)
> > 			break;
> > 		}
> > 	}
> > +
> > +	if (base < rgn->region[0].base) {
> > +		rgn->region[0].base = base;
> > +		rgn->region[0].size = size;
> > +	}
> > 	rgn->cnt++;
> >
> > 	return 0;
>
> Are you sure this is sufficient?
>
> It seems to me, to handle this properly, you'll need to handle
> the case where the lower addressed entry you are inserting is
> not contiguous with the existing entry 0.
>
> Therefore, you need to move all existing entries up a slot,
> then you can set the 0 entry to 'base' and 'size'.

The for loop above the code I added will move all the existing slots  
up one.  Its just the tail cleanup we are missing.

- k
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