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Date: Thu, 22 Mar 2018 20:55:25 -0400
From: jglisse@...hat.com
To: linux-mm@...ck.org
Cc: Andrew Morton <akpm@...ux-foundation.org>,
linux-kernel@...r.kernel.org,
Jérôme Glisse <jglisse@...hat.com>,
Evgeny Baskakov <ebaskakov@...dia.com>,
Ralph Campbell <rcampbell@...dia.com>,
Mark Hairgrove <mhairgrove@...dia.com>
Subject: [PATCH 13/15] mm/hmm: factor out pte and pmd handling to simplify hmm_vma_walk_pmd() v2
From: Jérôme Glisse <jglisse@...hat.com>
No functional change, just create one function to handle pmd and one
to handle pte (hmm_vma_handle_pmd() and hmm_vma_handle_pte()).
Changed since v1:
- s/pfns/pfn for pte as in that case we are dealing with a single pfn
Signed-off-by: Jérôme Glisse <jglisse@...hat.com>
Reviewed-by: John Hubbard <jhubbard@...dia.com>
Cc: Evgeny Baskakov <ebaskakov@...dia.com>
Cc: Ralph Campbell <rcampbell@...dia.com>
Cc: Mark Hairgrove <mhairgrove@...dia.com>
---
mm/hmm.c | 174 +++++++++++++++++++++++++++++++++++++--------------------------
1 file changed, 102 insertions(+), 72 deletions(-)
diff --git a/mm/hmm.c b/mm/hmm.c
index 05b49a5d6674..2cc4dda1fd2e 100644
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -375,6 +375,99 @@ static int hmm_vma_walk_hole(unsigned long addr,
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 *pfn)
+{
+ struct hmm_vma_walk *hmm_vma_walk = walk->private;
+ struct vm_area_struct *vma = walk->vma;
+ pte_t pte = *ptep;
+
+ *pfn = 0;
+
+ if (pte_none(pte)) {
+ *pfn = 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)) {
+ *pfn = hmm_pfn_from_pfn(swp_offset(entry));
+ if (is_write_device_private_entry(entry)) {
+ *pfn |= HMM_PFN_WRITE;
+ } else if ((hmm_vma_walk->fault & hmm_vma_walk->write))
+ goto fault;
+ *pfn |= 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 */
+ *pfn = HMM_PFN_ERROR;
+ return -EFAULT;
+ }
+
+ if ((hmm_vma_walk->fault & hmm_vma_walk->write) && !pte_write(pte))
+ goto fault;
+
+ *pfn = hmm_pfn_from_pfn(pte_pfn(pte));
+ *pfn |= pte_write(pte) ? HMM_PFN_WRITE : 0;
+ return 0;
+
+fault:
+ pte_unmap(ptep);
+ /* Fault any virtual address we were asked 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,
@@ -382,25 +475,20 @@ 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;
/*
@@ -416,17 +504,8 @@ static int hmm_vma_walk_pmd(pmd_t *pmdp,
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))
@@ -434,67 +513,18 @@ static int hmm_vma_walk_pmd(pmd_t *pmdp,
ptep = pte_offset_map(pmdp, addr);
for (; addr < end; addr += PAGE_SIZE, ptep++, i++) {
- pte_t pte = *ptep;
-
- pfns[i] = 0;
-
- 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;
- }
+ int r;
- /*
- * 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 asked to fault */
- return hmm_vma_walk_hole(start, end, walk);
}
pte_unmap(ptep - 1);
+ hmm_vma_walk->last = addr;
return 0;
}
--
2.14.3
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