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authorBaolin Wang <baolin.wang@linux.alibaba.com>2022-05-13 16:48:55 -0700
committerAndrew Morton <akpm@linux-foundation.org>2022-05-13 16:48:55 -0700
commitae07562909f3dfcdff40f87e51965728dab50485 (patch)
tree7801aceee552345779da81d937eef847a8807c8b /arch/s390/include/asm/hugetlb.h
parent110bf7a523075e42703fbe9c136ad00b867bec3a (diff)
mm: change huge_ptep_clear_flush() to return the original pte
Patch series "Fix CONT-PTE/PMD size hugetlb issue when unmapping or migrating", v4. presently, migrating a hugetlb page or unmapping a poisoned hugetlb page, we'll use ptep_clear_flush() and set_pte_at() to nuke the page table entry and remap it, and this is incorrect for CONT-PTE or CONT-PMD size hugetlb page, which will cause potential data consistent issue. This patch set will change to use hugetlb related APIs to fix this issue. Note: Mike pointed out the huge_ptep_get() will only return the one specific value, and it would not take into account the dirty or young bits of CONT-PTE/PMDs like the huge_ptep_get_and_clear() [1]. This inconsistent issue is not introduced by this patch set, and this issue will be addressed in another thread [2]. Meanwhile the uffd for hugetlb case [3] pointed out by Gerald also needs another patch to address. [1] https://lore.kernel.org/linux-mm/85bd80b4-b4fd-0d3f-a2e5-149559f2f387@oracle.com/ [2] https://lore.kernel.org/all/cover.1651998586.git.baolin.wang@linux.alibaba.com/ [3] https://lore.kernel.org/linux-mm/20220503120343.6264e126@thinkpad/ This patch (of 3): It is incorrect to use ptep_clear_flush() to nuke a hugetlb page table when unmapping or migrating a hugetlb page, and will change to use huge_ptep_clear_flush() instead in the following patches. So this is a preparation patch, which changes the huge_ptep_clear_flush() to return the original pte to help to nuke a hugetlb page table. [baolin.wang@linux.alibaba.com: fix build in several more architectures] Link: https://lkml.kernel.org/r/0009a4cd-2826-e8be-e671-f050d4f18d5d@linux.alibaba.com [sfr@canb.auug.org.au: fixup] Link: https://lkml.kernel.org/r/20220511181531.7f27a5c1@canb.auug.org.au Link: https://lkml.kernel.org/r/cover.1652270205.git.baolin.wang@linux.alibaba.com Link: https://lkml.kernel.org/r/20f77ddab90baa249bd24504c413189b82acde69.1652270205.git.baolin.wang@linux.alibaba.com Link: https://lkml.kernel.org/r/cover.1652147571.git.baolin.wang@linux.alibaba.com Link: https://lkml.kernel.org/r/dcf065868cce35bceaf138613ad27f17bb7c0c19.1652147571.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Helge Deller <deller@gmx.de> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Yoshinori Sato <ysato@users.osdn.me> Cc: Rich Felker <dalias@libc.org> Cc: David S. Miller <davem@davemloft.net> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'arch/s390/include/asm/hugetlb.h')
-rw-r--r--arch/s390/include/asm/hugetlb.h6
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/s390/include/asm/hugetlb.h b/arch/s390/include/asm/hugetlb.h
index 32c3fd6e878e..f22beda9e6d5 100644
--- a/arch/s390/include/asm/hugetlb.h
+++ b/arch/s390/include/asm/hugetlb.h
@@ -50,10 +50,10 @@ static inline void huge_pte_clear(struct mm_struct *mm, unsigned long addr,
set_pte(ptep, __pte(_SEGMENT_ENTRY_EMPTY));
}
-static inline void huge_ptep_clear_flush(struct vm_area_struct *vma,
- unsigned long address, pte_t *ptep)
+static inline pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
+ unsigned long address, pte_t *ptep)
{
- huge_ptep_get_and_clear(vma->vm_mm, address, ptep);
+ return huge_ptep_get_and_clear(vma->vm_mm, address, ptep);
}
static inline int huge_ptep_set_access_flags(struct vm_area_struct *vma,