From: Jérôme Glisse <jglisse@xxxxxxxxxx>
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.
Signed-off-by: Jérôme Glisse <jglisse@xxxxxxxxxx>
Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Evgeny Baskakov <ebaskakov@xxxxxxxxxx>
Cc: Ralph Campbell <rcampbell@xxxxxxxxxx>
Cc: Mark Hairgrove <mhairgrove@xxxxxxxxxx>
---
mm/hmm.c | 40 ++++++++++++++++++++--------------------
1 file changed, 20 insertions(+), 20 deletions(-)
diff --git a/mm/hmm.c b/mm/hmm.c
index b4db0b1b709a..2df69a95c5ab 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -300,14 +300,6 @@ 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)
@@ -505,6 +497,14 @@ static int hmm_vma_walk_pmd(pmd_t *pmdp,
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
@@ -529,12 +529,6 @@ 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;
@@ -548,6 +542,12 @@ 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
@@ -716,6 +716,12 @@ 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
@@ -727,12 +733,6 @@ 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;
--
2.14.3
