[PATCH 7/7] fs: Fix a confusing error about overlapping regions

[Tom Rini]

On Sun, Sep 03, 2023 at 12:06:13PM -0600, Simon Glass wrote:
> Hi Tom,
> 
> On Sun, 3 Sept 2023 at 10:42, Tom Rini <trini at konsulko.com> wrote:
> >
> > On Thu, Aug 31, 2023 at 06:15:19PM -0600, Simon Glass wrote:
> > > Hi Tom,
> > >
> > > On Wed, 23 Aug 2023 at 09:14, Tom Rini <trini at konsulko.com> wrote:
> > > >
> > > > On Wed, Aug 23, 2023 at 07:42:03AM -0600, Simon Glass wrote:
> > > >
> > > > > When lmb runs out of space in its internal tables, it gives errors on
> > > > > every fs load operation. This is horribly confusing, as the poor user
> > > > > tries different memory regions one at a time.
> > > > >
> > > > > Use the updated API to check the error code and print a helpful message.
> > > > > Also, allow the operation to proceed.
> > > > >
> > > > > Update the tests accordingly.
> > > > >
> > > > > Signed-off-by: Simon Glass <sjg at chromium.org>
> > > > [snip]
> > > > > +     if (ret == -E2BIG) {
> > > > > +             log_warning("Reservation tables exhausted: see CONFIG_LMB_USE_MAX_REGIONS\n");
> > > > > +             return 0;
> > > > > +     }
> > > >
> > > > This isn't the right option.  Everyone has CONFIG_LMB_USE_MAX_REGIONS
> > > > set.  You would want to increase CONFIG_LMB_MAX_REGIONS.
> > > >
> > > > But it sounds like what you've found and fixed is an underlying problem
> > > > as to why 16 regions isn't enough in some common cases now?  So we could
> > >
> > > I don't think I have fixed anything. But I'll send v2 and perhaps it
> > > will be clearer what is going on here.
> > >
> > > > possibly avoid the string size growth here and have a comment that also
> > > > matches up with the help under LMB_MAX_REGIONS?
> > >
> > > I don't know, sorry. The size of struct(lmb) on 64-bit sandbox is
> > > about 400 bytes. There seems to be a lot of code to save not much
> > > memory.
> >
> > What do you mean here?  The alternative is not unlimited ranges but
> > instead to define the limit of memory regions and limit of reserved
> > ranges.
> 
> A better alternative would be not to limit the number of regions, IMO,
> i.e. have an array of regions that can grow as needed.

That's not something that we have in the code today, however.

-- 
Tom
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