linux-stable.git/include/linux/hmm.h, branch v5.3.7

mm/hmm: move hmm_vma_range_done and hmm_vma_fault to nouveau

2019-07-25T19:14:39+00:00

These two functions are marked as a legacy APIs to get rid of, but seem to
suit the current nouveau flow.  Move it to the only user in preparation
for fixing a locking bug involving caller and callee.  All comments
referring to the old API have been removed as this now is a driver private
helper.

Link: https://lore.kernel.org/r/20190724065258.16603-3-hch@lst.de
Tested-by: Ralph Campbell 
Signed-off-by: Christoph Hellwig 
Reviewed-by: Jason Gunthorpe 
Signed-off-by: Jason Gunthorpe

Merge branch 'hmm-devmem-cleanup.4' into rdma.git hmm

2019-07-02T18:10:45+00:00

Christoph Hellwig says:

====================
Below is a series that cleans up the dev_pagemap interface so that it is
more easily usable, which removes the need to wrap it in hmm and thus
allowing to kill a lot of code

Changes since v3:
 - pull in "mm/swap: Fix release_pages() when releasing devmap pages" and
   rebase the other patches on top of that
 - fold the hmm_devmem_add_resource into the DEVICE_PUBLIC memory removal
   patch
 - remove _vm_normal_page as it isn't needed without DEVICE_PUBLIC memory
 - pick up various ACKs

Changes since v2:
 - fix nvdimm kunit build
 - add a new memory type for device dax
 - fix a few issues in intermediate patches that didn't show up in the end
   result
 - incorporate feedback from Michal Hocko, including killing of
   the DEVICE_PUBLIC memory type entirely

Changes since v1:
 - rebase
 - also switch p2pdma to the internal refcount
 - add type checking for pgmap->type
 - rename the migrate method to migrate_to_ram
 - cleanup the altmap_valid flag
 - various tidbits from the reviews
====================

Conflicts resolved by:
 - Keeping Ira's version of the code in swap.c
 - Using the delete for the section in hmm.rst
 - Using the delete for the devmap code in hmm.c and .h

* branch 'hmm-devmem-cleanup.4': (24 commits)
  mm: don't select MIGRATE_VMA_HELPER from HMM_MIRROR
  mm: remove the HMM config option
  mm: sort out the DEVICE_PRIVATE Kconfig mess
  mm: simplify ZONE_DEVICE page private data
  mm: remove hmm_devmem_add
  mm: remove hmm_vma_alloc_locked_page
  nouveau: use devm_memremap_pages directly
  nouveau: use alloc_page_vma directly
  PCI/P2PDMA: use the dev_pagemap internal refcount
  device-dax: use the dev_pagemap internal refcount
  memremap: provide an optional internal refcount in struct dev_pagemap
  memremap: replace the altmap_valid field with a PGMAP_ALTMAP_VALID flag
  memremap: remove the data field in struct dev_pagemap
  memremap: add a migrate_to_ram method to struct dev_pagemap_ops
  memremap: lift the devmap_enable manipulation into devm_memremap_pages
  memremap: pass a struct dev_pagemap to ->kill and ->cleanup
  memremap: move dev_pagemap callbacks into a separate structure
  memremap: validate the pagemap type passed to devm_memremap_pages
  mm: factor out a devm_request_free_mem_region helper
  mm: export alloc_pages_vma
  ...

Signed-off-by: Jason Gunthorpe

mm: remove the HMM config option

2019-07-02T17:32:45+00:00

All the mm/hmm.c code is better keyed off HMM_MIRROR.  Also let nouveau
depend on it instead of the mix of a dummy dependency symbol plus the
actually selected one.  Drop various odd dependencies, as the code is
pretty portable.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Ira Weiny 
Reviewed-by: Jason Gunthorpe 
Reviewed-by: Dan Williams 
Signed-off-by: Jason Gunthorpe

mm: simplify ZONE_DEVICE page private data

2019-07-02T17:32:45+00:00

Remove the clumsy hmm_devmem_page_{get,set}_drvdata helpers, and
instead just access the page directly.  Also make the page data
a void pointer, and thus much easier to use.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Dan Williams 
Signed-off-by: Jason Gunthorpe

mm: remove hmm_devmem_add

2019-07-02T17:32:45+00:00

There isn't really much value add in the hmm_devmem_add wrapper and
more, as using devm_memremap_pages directly now is just as simple.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Jason Gunthorpe 
Reviewed-by: Dan Williams 
Signed-off-by: Jason Gunthorpe

mm: remove hmm_vma_alloc_locked_page

2019-07-02T17:32:44+00:00

The only user of it has just been removed, and there wasn't really any need
to wrap a basic memory allocator to start with.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Jason Gunthorpe 
Reviewed-by: Dan Williams 
Signed-off-by: Jason Gunthorpe

memremap: add a migrate_to_ram method to struct dev_pagemap_ops

2019-07-02T17:32:44+00:00

This replaces the hacky ->fault callback, which is currently directly
called from common code through a hmm specific data structure as an
exercise in layering violations.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Ralph Campbell 
Reviewed-by: Jason Gunthorpe 
Reviewed-by: Dan Williams 
Tested-by: Dan Williams 
Signed-off-by: Jason Gunthorpe

mm: remove MEMORY_DEVICE_PUBLIC support

2019-07-02T17:32:43+00:00

The code hasn't been used since it was added to the tree, and doesn't
appear to actually be usable.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Jason Gunthorpe 
Acked-by: Michal Hocko 
Reviewed-by: Dan Williams 
Tested-by: Dan Williams 
Signed-off-by: Jason Gunthorpe

mm: remove the struct hmm_device infrastructure

2019-07-02T14:59:21+00:00

This code is a trivial wrapper around device model helpers, which
should have been integrated into the driver device model usage from
the start.  Assuming it actually had users, which it never had since
the code was added more than 1 1/2 years ago.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Jason Gunthorpe 
Reviewed-by: John Hubbard 
Reviewed-by: Dan Williams 
Signed-off-by: Jason Gunthorpe

mm/hmm: Fix error flows in hmm_invalidate_range_start

2019-06-27T16:05:02+00:00

If the trylock on the hmm->mirrors_sem fails the function will return
without decrementing the notifiers that were previously incremented. Since
the caller will not call invalidate_range_end() on EAGAIN this will result
in notifiers becoming permanently incremented and deadlock.

If the sync_cpu_device_pagetables() required blocking the function will
not return EAGAIN even though the device continues to touch the
pages. This is a violation of the mmu notifier contract.

Switch, and rename, the ranges_lock to a spin lock so we can reliably
obtain it without blocking during error unwind.

The error unwind is necessary since the notifiers count must be held
incremented across the call to sync_cpu_device_pagetables() as we cannot
allow the range to become marked valid by a parallel
invalidate_start/end() pair while doing sync_cpu_device_pagetables().

Signed-off-by: Jason Gunthorpe 
Reviewed-by: Ralph Campbell 
Reviewed-by: Christoph Hellwig 
Tested-by: Philip Yang