The patch titled
Subject: mm/hmm: do not erase snapshot when a range is invalidated
has been added to the -mm tree. Its filename is
mm-hmm-do-not-erase-snapshot-when-a-range-is-invalidated.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-hmm-do-not-erase-snapshot-when-a-range-is-invalidated.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-hmm-do-not-erase-snapshot-when-a-range-is-invalidated.patch
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------------------------------------------------------
From: Jérôme Glisse <jglisse@xxxxxxxxxx>
Subject: mm/hmm: do not erase snapshot when a range is invalidated
Users of HMM might be using the snapshot information to do preparatory
step like dma mapping pages to a device before checking for invalidation
through hmm_vma_range_done() so do not erase that information and assume
users will do the right thing.
Link: http://lkml.kernel.org/r/20190129165428.3931-3-jglisse@xxxxxxxxxx
Signed-off-by: Jérôme Glisse <jglisse@xxxxxxxxxx>
Cc: Ralph Campbell <rcampbell@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Christian König <christian.koenig@xxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Felix Kuehling <Felix.Kuehling@xxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hmm.c | 6 ------
1 file changed, 6 deletions(-)
--- a/mm/hmm.c~mm-hmm-do-not-erase-snapshot-when-a-range-is-invalidated
+++ a/mm/hmm.c
@@ -170,16 +170,10 @@ static int hmm_invalidate_range(struct h
spin_lock(&hmm->lock);
list_for_each_entry(range, &hmm->ranges, list) {
- unsigned long addr, idx, npages;
-
if (update->end < range->start || update->start >= range->end)
continue;
range->valid = false;
- addr = max(update->start, range->start);
- idx = (addr - range->start) >> PAGE_SHIFT;
- npages = (min(range->end, update->end) - addr) >> PAGE_SHIFT;
- memset(&range->pfns[idx], 0, sizeof(*range->pfns) * npages);
}
spin_unlock(&hmm->lock);
_
Patches currently in -mm which might be from jglisse@xxxxxxxxxx are
mm-hmm-use-reference-counting-for-hmm-struct.patch
mm-hmm-do-not-erase-snapshot-when-a-range-is-invalidated.patch
mm-hmm-improve-and-rename-hmm_vma_get_pfns-to-hmm_range_snapshot.patch
mm-hmm-improve-and-rename-hmm_vma_fault-to-hmm_range_fault.patch
mm-hmm-improve-driver-api-to-work-and-wait-over-a-range.patch
mm-hmm-add-default-fault-flags-to-avoid-the-need-to-pre-fill-pfns-arrays.patch
mm-hmm-add-an-helper-function-that-fault-pages-and-map-them-to-a-device.patch
mm-hmm-support-hugetlbfs-snap-shoting-faulting-and-dma-mapping.patch
mm-hmm-allow-to-mirror-vma-of-a-file-on-a-dax-backed-filesystem.patch
mm-hmm-add-helpers-for-driver-to-safely-take-the-mmap_sem.patch
mm-mmu_notifier-contextual-information-for-event-triggering-invalidation-v2.patch
mm-mmu_notifier-contextual-information-for-event-triggering-invalidation-v2-fix.patch
