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[NTOS:MM] Simplify refcounting when adding/deleting a page in a shared segment

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CORE-17544
This commit is contained in:
Jérôme Gardou 2021-06-07 19:28:51 +02:00 • committed by Jérôme Gardou
parent bec42b6530
commit b3e9c89725
2 changed files with 11 additions and 5 deletions
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13
ntoskrnl/cache/section/sptab.c vendored
View file

@ -204,6 +204,16 @@ _MmSetPageEntrySectionSegment(PMM_SECTION_SEGMENT Segment,
OldEntry, OldEntry,
Entry); Entry);
/* Manage ref on segment */
if (Entry && !OldEntry)
{
InterlockedIncrement64(Segment->ReferenceCount);
}
if (OldEntry && !Entry)
{
MmDereferenceSegment(Segment);
}
if (Entry && !IS_SWAP_FROM_SSE(Entry)) if (Entry && !IS_SWAP_FROM_SSE(Entry))
{ {
/* We have a valid entry. See if we must do something */ /* We have a valid entry. See if we must do something */
@ -223,7 +233,6 @@ _MmSetPageEntrySectionSegment(PMM_SECTION_SEGMENT Segment,
* Add the Rmap and take a ref on the segment. * Add the Rmap and take a ref on the segment.
*/ */
MmSetSectionAssociation(PFN_FROM_SSE(Entry), Segment, Offset); MmSetSectionAssociation(PFN_FROM_SSE(Entry), Segment, Offset);
InterlockedIncrement64(Segment->ReferenceCount);
if (Offset->QuadPart >= (Segment->LastPage << PAGE_SHIFT)) if (Offset->QuadPart >= (Segment->LastPage << PAGE_SHIFT))
Segment->LastPage = (Offset->QuadPart >> PAGE_SHIFT) + 1; Segment->LastPage = (Offset->QuadPart >> PAGE_SHIFT) + 1;
@ -233,7 +242,6 @@ _MmSetPageEntrySectionSegment(PMM_SECTION_SEGMENT Segment,
{ {
/* We're switching to an invalid entry from a valid one */ /* We're switching to an invalid entry from a valid one */
MmDeleteSectionAssociation(PFN_FROM_SSE(OldEntry)); MmDeleteSectionAssociation(PFN_FROM_SSE(OldEntry));
MmDereferenceSegment(Segment);
if (Offset->QuadPart == ((Segment->LastPage - 1ULL) << PAGE_SHIFT)) if (Offset->QuadPart == ((Segment->LastPage - 1ULL) << PAGE_SHIFT))
{ {
@ -363,6 +371,7 @@ MmGetSectionAssociation(PFN_NUMBER Page,
Offset->QuadPart = PageTable->FileOffset.QuadPart + Offset->QuadPart = PageTable->FileOffset.QuadPart +
((ULONG64)RawOffset << PAGE_SHIFT); ((ULONG64)RawOffset << PAGE_SHIFT);
ASSERT(PFN_FROM_SSE(PageTable->PageEntries[RawOffset]) == Page); ASSERT(PFN_FROM_SSE(PageTable->PageEntries[RawOffset]) == Page);
InterlockedIncrement64(Segment->ReferenceCount);
} }
return Segment; return Segment;

3
ntoskrnl/mm/rmap.c
View file

@ -300,7 +300,6 @@ WriteSegment:
Released = MmCheckDirtySegment(Segment, &SegmentOffset, FALSE, TRUE); Released = MmCheckDirtySegment(Segment, &SegmentOffset, FALSE, TRUE);
MmUnlockSectionSegment(Segment); MmUnlockSectionSegment(Segment);
MmDereferenceSegment(Segment); MmDereferenceSegment(Segment);
if (Released) if (Released)
@ -475,8 +474,6 @@ MmGetSegmentRmap(PFN_NUMBER Page, PULONG RawOffset)
MiReleasePfnLock(OldIrql); MiReleasePfnLock(OldIrql);
return NULL; return NULL;
} }
InterlockedIncrement64(Result->Segment->ReferenceCount);
MiReleasePfnLock(OldIrql); MiReleasePfnLock(OldIrql);
return Result; return Result;
} }