Re: [PATCH 2/3] xfs: add kmem_alloc_io()

[Christoph Hellwig]

On Thu, Aug 22, 2019 at 10:31:32AM +1000, Dave Chinner wrote:
> > Btw, I think we should eventually kill off KM_NOFS and just use
> > PF_MEMALLOC_NOFS in XFS, as the interface makes so much more sense.
> > But that's something for the future.
> 
> Yeah, and it's not quite as simple as just using PF_MEMALLOC_NOFS
> at high levels - we'll still need to annotate callers that use KM_NOFS
> to avoid lockdep false positives. i.e. any code that can be called from
> GFP_KERNEL and reclaim context will throw false positives from
> lockdep if we don't annotate tehm correctly....

Oh well.  For now we have the XFS kmem_wrappers to turn that into
GFP_NOFS so we shouldn't be too worried, but I think that is something
we should fix in lockdep to ensure it is generally useful.  I've added
the maintainers and relevant lists to kick off a discussion.