RE: [Patch v3 01/14] x86/ioremap: Fix page aligned size calculation in __ioremap_caller()

[Michael Kelley (LINUX)]

From: Dave Hansen <dave.hansen@xxxxxxxxx> Sent: Monday, November 21, 2022 10:14 AM
> 
> On 11/16/22 10:41, Michael Kelley wrote:
> > Current code re-calculates the size after aligning the starting and
> > ending physical addresses on a page boundary. But the re-calculation
> > also embeds the masking of high order bits that exceed the size of
> > the physical address space (via PHYSICAL_PAGE_MASK). If the masking
> > removes any high order bits, the size calculation results in a huge
> > value that is likely to immediately fail.
> >
> > Fix this by re-calculating the page-aligned size first. Then mask any
> > high order bits using PHYSICAL_PAGE_MASK.
> >
> > Signed-off-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
> 
> Looks good:
> 
> Acked-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
> 
> Although I do agree with Boris that this superficially looks like
> something that's important to backport.  It would be best to either beef
> up the changelog to explain why that's not the case, or to treat this as
> an actual fix and submit separately.

You and Boris agree and I have no objection, so I'll add the "Fixes:" tag.
I'd like to keep the patch as part of this series because it *is* needed to
make the series work.

Michael