The patch titled
Subject: mm/hmm: cleanup special vma handling (VM_SPECIAL)
has been added to the -mm tree. Its filename is
mm-hmm-cleanup-special-vma-handling-vm_special.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-hmm-cleanup-special-vma-handling-vm_special.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-hmm-cleanup-special-vma-handling-vm_special.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Jérôme Glisse <jglisse@xxxxxxxxxx>
Subject: mm/hmm: cleanup special vma handling (VM_SPECIAL)
Special vma (one with any of the VM_SPECIAL flags) can not be accessed by
devicees because there is no consistent model across device drivers on
those vmas and their backing memory.
This patch directly uses hmm_range struct for hmm_pfns_special() argument
as it is always affecting the whole vma and thus the whole range.
It also makes behavior consistent: after this patch both hmm_vma_fault()
and hmm_vma_get_pfns() return -EINVAL when facing such vmas. Previously
hmm_vma_fault() returned 0 and hmm_vma_get_pfns() returned -EINVAL but
both were filling the HMM pfn array with special entries.
Link: http://lkml.kernel.org/r/20180316191414.3223-9-jglisse@xxxxxxxxxx
Signed-off-by: Jérôme Glisse <jglisse@xxxxxxxxxx>
Cc: Evgeny Baskakov <ebaskakov@xxxxxxxxxx>
Cc: Ralph Campbell <rcampbell@xxxxxxxxxx>
Cc: Mark Hairgrove <mhairgrove@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hmm.c | 40 ++++++++++++++++++++--------------------
1 file changed, 20 insertions(+), 20 deletions(-)
diff -puN mm/hmm.c~mm-hmm-cleanup-special-vma-handling-vm_special mm/hmm.c
--- a/mm/hmm.c~mm-hmm-cleanup-special-vma-handling-vm_special
+++ a/mm/hmm.c
@@ -281,14 +281,6 @@ static int hmm_vma_do_fault(struct mm_wa
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)
@@ -486,6 +478,14 @@ 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 snapshoted and all needed informations
@@ -509,12 +509,6 @@ int hmm_vma_get_pfns(struct hmm_range *r
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;
@@ -528,6 +522,12 @@ int hmm_vma_get_pfns(struct hmm_range *r
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;
+ }
+
/* Initialize range to track CPU page table update */
spin_lock(&hmm->lock);
range->valid = true;
@@ -693,6 +693,12 @@ int hmm_vma_fault(struct hmm_range *rang
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;
+ }
+
/* Initialize range to track CPU page table update */
spin_lock(&hmm->lock);
range->valid = true;
@@ -710,12 +716,6 @@ int hmm_vma_fault(struct hmm_range *rang
return 0;
}
- /* 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;
- }
-
hmm_vma_walk.fault = true;
hmm_vma_walk.write = write;
hmm_vma_walk.block = block;
_
Patches currently in -mm which might be from jglisse@xxxxxxxxxx are
mm-hmm-fix-header-file-if-else-endif-maze.patch
mm-hmm-hmm_pfns_bad-was-accessing-wrong-struct.patch
mm-hmm-use-struct-for-hmm_vma_fault-hmm_vma_get_pfns-parameters.patch
mm-hmm-remove-hmm_pfn_read-flag-and-ignore-peculiar-architecture.patch
mm-hmm-use-uint64_t-for-hmm-pfn-instead-of-defining-hmm_pfn_t-to-ulong.patch
mm-hmm-cleanup-special-vma-handling-vm_special.patch
mm-hmm-do-not-differentiate-between-empty-entry-or-missing-directory.patch
mm-hmm-rename-hmm_pfn_device_unaddressable-to-hmm_pfn_device_private.patch
mm-hmm-move-hmm_pfns_clear-closer-to-where-it-is-use.patch
mm-hmm-factor-out-pte-and-pmd-handling-to-simplify-hmm_vma_walk_pmd.patch
mm-hmm-change-hmm_vma_fault-to-allow-write-fault-on-page-basis.patch
mm-hmm-use-device-driver-encoding-for-hmm-pfn.patch
--
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