mm/hmm: change hmm_vma_fault() to allow write fault on page basis
authorJérôme Glisse <jglisse@redhat.com>
Tue, 10 Apr 2018 23:29:02 +0000 (16:29 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 11 Apr 2018 17:28:31 +0000 (10:28 -0700)
commit2aee09d8c1164219971c7b396f2235bd5334018c
tree121ed9085293eeb478d1a8465514ab96ed5eb2a8
parent53f5c3f489ecddc7570a2e2422a6fc5b25007b9d
mm/hmm: change hmm_vma_fault() to allow write fault on page basis

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 <jglisse@redhat.com>
Cc: Evgeny Baskakov <ebaskakov@nvidia.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Mark Hairgrove <mhairgrove@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/hmm.h
mm/hmm.c