The patch titled
Subject: mm/hmm: factor out pte and pmd handling to simplify hmm_vma_walk_pmd()
has been added to the -mm tree. Its filename is
mm-hmm-factor-out-pte-and-pmd-handling-to-simplify-hmm_vma_walk_pmd.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-hmm-factor-out-pte-and-pmd-handling-to-simplify-hmm_vma_walk_pmd.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-hmm-factor-out-pte-and-pmd-handling-to-simplify-hmm_vma_walk_pmd.patch
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------------------------------------------------------
From: Jérôme Glisse <jglisse@xxxxxxxxxx>
Subject: mm/hmm: factor out pte and pmd handling to simplify hmm_vma_walk_pmd()
No functional change, just create one function to handle pmd and one to
handle pte (hmm_vma_handle_pmd() and hmm_vma_handle_pte()).
Link: http://lkml.kernel.org/r/20180320020038.3360-14-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>
Cc: Balbir Singh <bsingharora@xxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Cc: Logan Gunthorpe <logang@xxxxxxxxxxxx>
Cc: Stephen Bates <sbates@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
diff -puN mm/hmm.c~mm-hmm-factor-out-pte-and-pmd-handling-to-simplify-hmm_vma_walk_pmd mm/hmm.c
--- a/mm/hmm.c~mm-hmm-factor-out-pte-and-pmd-handling-to-simplify-hmm_vma_walk_pmd
+++ a/mm/hmm.c
@@ -351,6 +351,99 @@ static int hmm_vma_walk_hole(unsigned lo
return hmm_vma_walk->fault ? -EAGAIN : 0;
}
+static int hmm_vma_handle_pmd(struct mm_walk *walk,
+ unsigned long addr,
+ unsigned long end,
+ uint64_t *pfns,
+ pmd_t pmd)
+{
+ struct hmm_vma_walk *hmm_vma_walk = walk->private;
+ unsigned long pfn, i;
+ uint64_t flag = 0;
+
+ if (pmd_protnone(pmd))
+ return hmm_vma_walk_hole(addr, end, walk);
+
+ if ((hmm_vma_walk->fault & hmm_vma_walk->write) && !pmd_write(pmd))
+ return hmm_vma_walk_hole(addr, end, walk);
+
+ pfn = pmd_pfn(pmd) + pte_index(addr);
+ flag |= pmd_write(pmd) ? HMM_PFN_WRITE : 0;
+ for (i = 0; addr < end; addr += PAGE_SIZE, i++, pfn++)
+ pfns[i] = hmm_pfn_from_pfn(pfn) | flag;
+ hmm_vma_walk->last = end;
+ return 0;
+}
+
+static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr,
+ unsigned long end, pmd_t *pmdp, pte_t *ptep,
+ uint64_t *pfns)
+{
+ struct hmm_vma_walk *hmm_vma_walk = walk->private;
+ struct vm_area_struct *vma = walk->vma;
+ pte_t pte = *ptep;
+
+ *pfns = 0;
+
+ if (pte_none(pte)) {
+ *pfns = 0;
+ if (hmm_vma_walk->fault)
+ goto fault;
+ return 0;
+ }
+
+ if (!pte_present(pte)) {
+ swp_entry_t entry = pte_to_swp_entry(pte);
+
+ if (!non_swap_entry(entry)) {
+ if (hmm_vma_walk->fault)
+ goto fault;
+ return 0;
+ }
+
+ /*
+ * This is a special swap entry, ignore migration, use
+ * device and report anything else as error.
+ */
+ if (is_device_private_entry(entry)) {
+ *pfns = hmm_pfn_from_pfn(swp_offset(entry));
+ if (is_write_device_private_entry(entry)) {
+ *pfns |= HMM_PFN_WRITE;
+ } else if ((hmm_vma_walk->fault & hmm_vma_walk->write))
+ goto fault;
+ *pfns |= HMM_PFN_DEVICE_PRIVATE;
+ return 0;
+ }
+
+ if (is_migration_entry(entry)) {
+ if (hmm_vma_walk->fault) {
+ pte_unmap(ptep);
+ hmm_vma_walk->last = addr;
+ migration_entry_wait(vma->vm_mm,
+ pmdp, addr);
+ return -EAGAIN;
+ }
+ return 0;
+ }
+
+ /* Report error for everything else */
+ *pfns = HMM_PFN_ERROR;
+ return -EFAULT;
+ }
+
+ if ((hmm_vma_walk->fault & hmm_vma_walk->write) && !pte_write(pte))
+ goto fault;
+
+ *pfns = hmm_pfn_from_pfn(pte_pfn(pte));
+ *pfns |= pte_write(pte) ? HMM_PFN_WRITE : 0;
+ return 0;
+
+fault:
+ pte_unmap(ptep);
+ /* Fault any virtual address we were ask to fault */
+ return hmm_vma_walk_hole(addr, end, walk);
+}
+
static int hmm_vma_walk_pmd(pmd_t *pmdp,
unsigned long start,
unsigned long end,
@@ -358,25 +451,20 @@ static int hmm_vma_walk_pmd(pmd_t *pmdp,
{
struct hmm_vma_walk *hmm_vma_walk = walk->private;
struct hmm_range *range = hmm_vma_walk->range;
- struct vm_area_struct *vma = walk->vma;
uint64_t *pfns = range->pfns;
unsigned long addr = start, i;
- bool write_fault;
pte_t *ptep;
i = (addr - range->start) >> PAGE_SHIFT;
- write_fault = hmm_vma_walk->fault & hmm_vma_walk->write;
again:
if (pmd_none(*pmdp))
return hmm_vma_walk_hole(start, end, walk);
- if (pmd_huge(*pmdp) && vma->vm_flags & VM_HUGETLB)
+ if (pmd_huge(*pmdp) && (range->vma->vm_flags & VM_HUGETLB))
return hmm_pfns_bad(start, end, walk);
if (pmd_devmap(*pmdp) || pmd_trans_huge(*pmdp)) {
- unsigned long pfn;
- uint64_t flag = 0;
pmd_t pmd;
/*
@@ -392,17 +480,8 @@ again:
barrier();
if (!pmd_devmap(pmd) && !pmd_trans_huge(pmd))
goto again;
- if (pmd_protnone(pmd))
- return hmm_vma_walk_hole(start, end, walk);
- if (write_fault && !pmd_write(pmd))
- return hmm_vma_walk_hole(start, end, walk);
-
- pfn = pmd_pfn(pmd) + pte_index(addr);
- flag |= pmd_write(pmd) ? HMM_PFN_WRITE : 0;
- for (; addr < end; addr += PAGE_SIZE, i++, pfn++)
- pfns[i] = hmm_pfn_from_pfn(pfn) | flag;
- return 0;
+ return hmm_vma_handle_pmd(walk, addr, end, &pfns[i], pmd);
}
if (pmd_bad(*pmdp))
@@ -410,67 +489,18 @@ again:
ptep = pte_offset_map(pmdp, addr);
for (; addr < end; addr += PAGE_SIZE, ptep++, i++) {
- pte_t pte = *ptep;
-
- pfns[i] = 0;
+ int r;
- if (pte_none(pte)) {
- pfns[i] = 0;
- if (hmm_vma_walk->fault)
- goto fault;
- continue;
- }
-
- if (!pte_present(pte)) {
- swp_entry_t entry = pte_to_swp_entry(pte);
-
- if (!non_swap_entry(entry)) {
- if (hmm_vma_walk->fault)
- goto fault;
- continue;
- }
-
- /*
- * This is a special swap entry, ignore migration, use
- * device and report anything else as error.
- */
- if (is_device_private_entry(entry)) {
- pfns[i] = hmm_pfn_from_pfn(swp_offset(entry));
- if (is_write_device_private_entry(entry)) {
- pfns[i] |= HMM_PFN_WRITE;
- } else if (write_fault)
- goto fault;
- pfns[i] |= HMM_PFN_DEVICE_PRIVATE;
- } else if (is_migration_entry(entry)) {
- if (hmm_vma_walk->fault) {
- pte_unmap(ptep);
- hmm_vma_walk->last = addr;
- migration_entry_wait(vma->vm_mm,
- pmdp, addr);
- return -EAGAIN;
- }
- continue;
- } else {
- /* Report error for everything else */
- pfns[i] = HMM_PFN_ERROR;
- }
- continue;
+ r = hmm_vma_handle_pte(walk, addr, end, pmdp, ptep, &pfns[i]);
+ if (r) {
+ /* hmm_vma_handle_pte() did unmap pte directory */
+ hmm_vma_walk->last = addr;
+ return r;
}
-
- if (write_fault && !pte_write(pte))
- goto fault;
-
- pfns[i] = hmm_pfn_from_pfn(pte_pfn(pte));
- pfns[i] |= pte_write(pte) ? HMM_PFN_WRITE : 0;
- continue;
-
-fault:
- pte_unmap(ptep);
- /* Fault any virtual address we were ask to fault */
- return hmm_vma_walk_hole(start, end, walk);
}
pte_unmap(ptep - 1);
+ hmm_vma_walk->last = addr;
return 0;
}
_
Patches currently in -mm which might be from jglisse@xxxxxxxxxx are
mm-hmm-fix-header-file-if-else-endif-maze-v2.patch
mm-hmm-unregister-mmu_notifier-when-last-hmm-client-quit.patch
mm-hmm-hmm_pfns_bad-was-accessing-wrong-struct.patch
mm-hmm-use-struct-for-hmm_vma_fault-hmm_vma_get_pfns-parameters-v2.patch
mm-hmm-remove-hmm_pfn_read-flag-and-ignore-peculiar-architecture-v2.patch
mm-hmm-use-uint64_t-for-hmm-pfn-instead-of-defining-hmm_pfn_t-to-ulong-v2.patch
mm-hmm-cleanup-special-vma-handling-vm_special.patch
mm-hmm-do-not-differentiate-between-empty-entry-or-missing-directory-v2.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-v2.patch
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