linux-stable.git/include/linux/hmm.h, branch v4.17.2

mm/hmm: fix header file if/else/endif maze, again

2018-04-11T17:28:31+00:00

The last fix was still wrong, as we need the inline dummy functions also
for the case that CONFIG_HMM is enabled but CONFIG_HMM_MIRROR is not:

  kernel/fork.o: In function `__mmdrop':
  fork.c:(.text+0x14f6): undefined reference to `hmm_mm_destroy'

This adds back the second copy of the dummy functions, hopefully
this time in the right place.

Link: http://lkml.kernel.org/r/20180404110236.804484-1-arnd@arndb.de
Fixes: 8900d06a277a ("mm/hmm: fix header file if/else/endif maze")
Signed-off-by: Arnd Bergmann 
Reviewed-by: Jérôme Glisse 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/hmm: use device driver encoding for HMM pfn

2018-04-11T17:28:31+00:00

Users of hmm_vma_fault() and hmm_vma_get_pfns() provide a flags array and
pfn shift value allowing them to define their own encoding for HMM pfn
that are fill inside the pfns array of the hmm_range struct.  With this
device driver can get pfn that match their own private encoding out of HMM
without having to do any conversion.

[rcampbell@nvidia.com: don't ignore specific pte fault flag in hmm_vma_fault()]
  Link: http://lkml.kernel.org/r/20180326213009.2460-2-jglisse@redhat.com
[rcampbell@nvidia.com: clarify fault logic for device private memory]
  Link: http://lkml.kernel.org/r/20180326213009.2460-3-jglisse@redhat.com
Link: http://lkml.kernel.org/r/20180323005527.758-16-jglisse@redhat.com
Signed-off-by: Jérôme Glisse 
Signed-off-by: Ralph Campbell 
Cc: Evgeny Baskakov 
Cc: Ralph Campbell 
Cc: Mark Hairgrove 
Cc: John Hubbard 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/hmm: change hmm_vma_fault() to allow write fault on page basis

2018-04-11T17:28:31+00:00

This changes hmm_vma_fault() to not take a global write fault flag for a
range but instead rely on caller to populate HMM pfns array with proper
fault flag ie HMM_PFN_VALID if driver want read fault for that address or
HMM_PFN_VALID and HMM_PFN_WRITE for write.

Moreover by setting HMM_PFN_DEVICE_PRIVATE the device driver can ask for
device private memory to be migrated back to system memory through page
fault.

This is more flexible API and it better reflects how device handles and
reports fault.

Link: http://lkml.kernel.org/r/20180323005527.758-15-jglisse@redhat.com
Signed-off-by: Jérôme Glisse 
Cc: Evgeny Baskakov 
Cc: Ralph Campbell 
Cc: Mark Hairgrove 
Cc: John Hubbard 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/hmm: rename HMM_PFN_DEVICE_UNADDRESSABLE to HMM_PFN_DEVICE_PRIVATE

2018-04-11T17:28:30+00:00

Make naming consistent across code, DEVICE_PRIVATE is the name use outside
HMM code so use that one.

Link: http://lkml.kernel.org/r/20180323005527.758-12-jglisse@redhat.com
Signed-off-by: Jérôme Glisse 
Reviewed-by: John Hubbard 
Cc: Evgeny Baskakov 
Cc: Ralph Campbell 
Cc: Mark Hairgrove 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/hmm: do not differentiate between empty entry or missing directory

2018-04-11T17:28:30+00:00

There is no point in differentiating between a range for which there is
not even a directory (and thus entries) and empty entry (pte_none() or
pmd_none() returns true).

Simply drop the distinction ie remove HMM_PFN_EMPTY flag and merge now
duplicate hmm_vma_walk_hole() and hmm_vma_walk_clear() functions.

Link: http://lkml.kernel.org/r/20180323005527.758-11-jglisse@redhat.com
Signed-off-by: Jérôme Glisse 
Reviewed-by: John Hubbard 
Cc: Evgeny Baskakov 
Cc: Ralph Campbell 
Cc: Mark Hairgrove 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/hmm: use uint64_t for HMM pfn instead of defining hmm_pfn_t to ulong

2018-04-11T17:28:30+00:00

All device driver we care about are using 64bits page table entry.  In
order to match this and to avoid useless define convert all HMM pfn to
directly use uint64_t.  It is a first step on the road to allow driver to
directly use pfn value return by HMM (saving memory and CPU cycles use for
conversion between the two).

Link: http://lkml.kernel.org/r/20180323005527.758-9-jglisse@redhat.com
Signed-off-by: Jérôme Glisse 
Reviewed-by: John Hubbard 
Cc: Evgeny Baskakov 
Cc: Ralph Campbell 
Cc: Mark Hairgrove 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/hmm: remove HMM_PFN_READ flag and ignore peculiar architecture

2018-04-11T17:28:30+00:00

Only peculiar architecture allow write without read thus assume that any
valid pfn do allow for read.  Note we do not care for write only because
it does make sense with thing like atomic compare and exchange or any
other operations that allow you to get the memory value through them.

Link: http://lkml.kernel.org/r/20180323005527.758-8-jglisse@redhat.com
Signed-off-by: Jérôme Glisse 
Reviewed-by: John Hubbard 
Cc: Evgeny Baskakov 
Cc: Ralph Campbell 
Cc: Mark Hairgrove 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/hmm: use struct for hmm_vma_fault(), hmm_vma_get_pfns() parameters

2018-04-11T17:28:30+00:00

Both hmm_vma_fault() and hmm_vma_get_pfns() were taking a hmm_range struct
as parameter and were initializing that struct with others of their
parameters.  Have caller of those function do this as they are likely to
already do and only pass this struct to both function this shorten
function signature and make it easier in the future to add new parameters
by simply adding them to the structure.

Link: http://lkml.kernel.org/r/20180323005527.758-7-jglisse@redhat.com
Signed-off-by: Jérôme Glisse 
Reviewed-by: John Hubbard 
Cc: Evgeny Baskakov 
Cc: Ralph Campbell 
Cc: Mark Hairgrove 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/hmm: HMM should have a callback before MM is destroyed

2018-04-11T17:28:30+00:00

hmm_mirror_register() registers a callback for when the CPU pagetable is
modified.  Normally, the device driver will call hmm_mirror_unregister()
when the process using the device is finished.  However, if the process
exits uncleanly, the struct_mm can be destroyed with no warning to the
device driver.

Link: http://lkml.kernel.org/r/20180323005527.758-4-jglisse@redhat.com
Signed-off-by: Ralph Campbell 
Signed-off-by: Jérôme Glisse 
Reviewed-by: John Hubbard 
Cc: Evgeny Baskakov 
Cc: Mark Hairgrove 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/hmm: fix header file if/else/endif maze

2018-04-11T17:28:30+00:00

The #if/#else/#endif for IS_ENABLED(CONFIG_HMM) were wrong.  Because of
this after multiple include there was multiple definition of both
hmm_mm_init() and hmm_mm_destroy() leading to build failure if HMM was
enabled (CONFIG_HMM set).

Link: http://lkml.kernel.org/r/20180323005527.758-3-jglisse@redhat.com
Signed-off-by: Jérôme Glisse 
Acked-by: Balbir Singh 
Cc: Andrew Morton 
Cc: Ralph Campbell 
Cc: John Hubbard 
Cc: Evgeny Baskakov 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds