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authorJérôme Glisse <jglisse@redhat.com>2018-04-10 16:28:46 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-11 10:28:30 -0700
commit5504ed29692faad06ea74c4275e96a8ffc83a1e1 (patch)
treefc5b15aa9076aeedd248c339b442ca7ad5c372e7 /mm/hmm.c
parent855ce7d2525c97cf706ad82a419f0c2d632b9481 (diff)
mm/hmm: do not differentiate between empty entry or missing directory
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 <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>
Diffstat (limited to 'mm/hmm.c')
-rw-r--r--mm/hmm.c45
1 files changed, 15 insertions, 30 deletions
diff --git a/mm/hmm.c b/mm/hmm.c
index a93c1e35df91..b8affe0bf4eb 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -348,6 +348,16 @@ static void hmm_pfns_clear(uint64_t *pfns,
*pfns = 0;
}
+/*
+ * hmm_vma_walk_hole() - handle a range lacking valid pmd or pte(s)
+ * @start: range virtual start address (inclusive)
+ * @end: range virtual end address (exclusive)
+ * @walk: mm_walk structure
+ * Returns: 0 on success, -EAGAIN after page fault, or page fault error
+ *
+ * This function will be called whenever pmd_none() or pte_none() returns true,
+ * or whenever there is no page directory covering the virtual address range.
+ */
static int hmm_vma_walk_hole(unsigned long addr,
unsigned long end,
struct mm_walk *walk)
@@ -360,31 +370,6 @@ static int hmm_vma_walk_hole(unsigned long addr,
hmm_vma_walk->last = addr;
i = (addr - range->start) >> PAGE_SHIFT;
for (; addr < end; addr += PAGE_SIZE, i++) {
- pfns[i] = HMM_PFN_EMPTY;
- if (hmm_vma_walk->fault) {
- int ret;
-
- ret = hmm_vma_do_fault(walk, addr, &pfns[i]);
- if (ret != -EAGAIN)
- return ret;
- }
- }
-
- return hmm_vma_walk->fault ? -EAGAIN : 0;
-}
-
-static int hmm_vma_walk_clear(unsigned long addr,
- unsigned long end,
- struct mm_walk *walk)
-{
- struct hmm_vma_walk *hmm_vma_walk = walk->private;
- struct hmm_range *range = hmm_vma_walk->range;
- uint64_t *pfns = range->pfns;
- unsigned long i;
-
- hmm_vma_walk->last = addr;
- i = (addr - range->start) >> PAGE_SHIFT;
- for (; addr < end; addr += PAGE_SIZE, i++) {
pfns[i] = 0;
if (hmm_vma_walk->fault) {
int ret;
@@ -440,10 +425,10 @@ again:
if (!pmd_devmap(pmd) && !pmd_trans_huge(pmd))
goto again;
if (pmd_protnone(pmd))
- return hmm_vma_walk_clear(start, end, walk);
+ return hmm_vma_walk_hole(start, end, walk);
if (write_fault && !pmd_write(pmd))
- return hmm_vma_walk_clear(start, end, walk);
+ return hmm_vma_walk_hole(start, end, walk);
pfn = pmd_pfn(pmd) + pte_index(addr);
flag |= pmd_write(pmd) ? HMM_PFN_WRITE : 0;
@@ -462,7 +447,7 @@ again:
pfns[i] = 0;
if (pte_none(pte)) {
- pfns[i] = HMM_PFN_EMPTY;
+ pfns[i] = 0;
if (hmm_vma_walk->fault)
goto fault;
continue;
@@ -513,8 +498,8 @@ again:
fault:
pte_unmap(ptep);
- /* Fault all pages in range */
- return hmm_vma_walk_clear(start, end, walk);
+ /* Fault any virtual address we were asked to fault */
+ return hmm_vma_walk_hole(start, end, walk);
}
pte_unmap(ptep - 1);