Re: [PATCH 4.4 03/34] mtd: nand: gpmi: Fix failure when a erased page has a bitflip at BBM

[Richard Weinberger]

Boris,

Am Mittwoch, 7. März 2018, 09:12:36 CET schrieb Boris Brezillon:
> On Tue, 06 Mar 2018 21:22:30 +0000
> 
> Ben Hutchings <ben.hutchings@xxxxxxxxxxxxxxx> wrote:
> > On Fri, 2018-03-02 at 09:50 +0100, Greg Kroah-Hartman wrote:
> > > 4.4-stable review patch.  If anyone has any objections, please let me
> > > know.
> > > 
> > > ------------------
> > > 
> > > From: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
> > > 
> > > 
> > > [ Upstream commit fdf2e821052958a114618a95ab18a300d0b080cb ]
> > > 
> > > When erased subpages are read then the BCH decoder returns STATUS_ERASED
> > > if they are all empty, or STATUS_UNCORRECTABLE if there are bitflips.
> > > When there are bitflips, we have to set these bits again to show the
> > > upper layers a completely erased page. When a bitflip happens in the
> > > exact byte where the bad block marker is, then this byte is swapped
> > > with another byte in block_mark_swapping(). The correction code then
> > > detects a bitflip in another subpage and no longer corrects the bitflip
> > > where it really happens.
> > 
> > [...]
> > 
> > This seesm to be a bug fix for commit bd2e778c9ee3 "gpmi-nand: Handle
> > ECC Errors in erased pages".  That's not in 4.4 so the bug fix is not
> > needed, though it doesn't appear to do any harm.
> 
> I wonder why the fix was backported to stable releases in the first
> place. AFAICS, there's no Cc-stable or Fixes tag in the original
> commit. It's probably something in the backport-to-stable process I'm
> not aware of.

It was auto selected by a stable script.

Thanks,
//richard