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authorJérôme Glisse <jglisse@redhat.com>2018-04-10 16:28:42 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-11 10:28:30 -0700
commit855ce7d2525c97cf706ad82a419f0c2d632b9481 (patch)
tree4c7cb4c0d14450792fdf512b5eb8e0832080ec8e
parentff05c0c6bbe5043af6a1686522ed845f40ba49ee (diff)
mm/hmm: cleanup special vma handling (VM_SPECIAL)
Special vma (one with any of the VM_SPECIAL flags) can not be access by device because there is no consistent model across device drivers on those vma and their backing memory. This patch directly use hmm_range struct for hmm_pfns_special() argument as it is always affecting the whole vma and thus the whole range. It also make behavior consistent after this patch both hmm_vma_fault() and hmm_vma_get_pfns() returns -EINVAL when facing such vma. Previously hmm_vma_fault() returned 0 and hmm_vma_get_pfns() return -EINVAL but both were filling the HMM pfn array with special entry. Link: http://lkml.kernel.org/r/20180323005527.758-10-jglisse@redhat.com Signed-off-by: Jérôme Glisse <jglisse@redhat.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Cc: Evgeny Baskakov <ebaskakov@nvidia.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Mark Hairgrove <mhairgrove@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/hmm.c40
1 files changed, 20 insertions, 20 deletions
diff --git a/mm/hmm.c b/mm/hmm.c
index b69f30fc064b..a93c1e35df91 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -324,14 +324,6 @@ static int hmm_vma_do_fault(struct mm_walk *walk,
return -EAGAIN;
}
-static void hmm_pfns_special(uint64_t *pfns,
- unsigned long addr,
- unsigned long end)
-{
- for (; addr < end; addr += PAGE_SIZE, pfns++)
- *pfns = HMM_PFN_SPECIAL;
-}
-
static int hmm_pfns_bad(unsigned long addr,
unsigned long end,
struct mm_walk *walk)
@@ -529,6 +521,14 @@ fault:
return 0;
}
+static void hmm_pfns_special(struct hmm_range *range)
+{
+ unsigned long addr = range->start, i = 0;
+
+ for (; addr < range->end; addr += PAGE_SIZE, i++)
+ range->pfns[i] = HMM_PFN_SPECIAL;
+}
+
/*
* hmm_vma_get_pfns() - snapshot CPU page table for a range of virtual addresses
* @range: range being snapshotted
@@ -553,12 +553,6 @@ int hmm_vma_get_pfns(struct hmm_range *range)
struct mm_walk mm_walk;
struct hmm *hmm;
- /* FIXME support hugetlb fs */
- if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL)) {
- hmm_pfns_special(range->pfns, range->start, range->end);
- return -EINVAL;
- }
-
/* Sanity check, this really should not happen ! */
if (range->start < vma->vm_start || range->start >= vma->vm_end)
return -EINVAL;
@@ -572,6 +566,12 @@ int hmm_vma_get_pfns(struct hmm_range *range)
if (!hmm->mmu_notifier.ops)
return -EINVAL;
+ /* FIXME support hugetlb fs */
+ if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL)) {
+ hmm_pfns_special(range);
+ return -EINVAL;
+ }
+
if (!(vma->vm_flags & VM_READ)) {
/*
* If vma do not allow read access, then assume that it does
@@ -740,6 +740,12 @@ int hmm_vma_fault(struct hmm_range *range, bool write, bool block)
if (!hmm->mmu_notifier.ops)
return -EINVAL;
+ /* FIXME support hugetlb fs */
+ if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL)) {
+ hmm_pfns_special(range);
+ return -EINVAL;
+ }
+
if (!(vma->vm_flags & VM_READ)) {
/*
* If vma do not allow read access, then assume that it does
@@ -751,12 +757,6 @@ int hmm_vma_fault(struct hmm_range *range, bool write, bool block)
return -EPERM;
}
- /* FIXME support hugetlb fs */
- if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL)) {
- hmm_pfns_special(range->pfns, range->start, range->end);
- return 0;
- }
-
/* Initialize range to track CPU page table update */
spin_lock(&hmm->lock);
range->valid = true;