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mm: page_vma_mapped_walk(): add a level of indentation 

page_vma_mapped_walk() cleanup: add a level of indentation to much of
the body, making no functional change in this commit, but reducing the
later diff when this is all converted to a loop.

[hughd@google.com: : page_vma_mapped_walk(): add a level of indentation fix]
  Link: https://lkml.kernel.org/r/7f817555-3ce1-c785-e438-87d8efdcaf26@google.com

Link: https://lkml.kernel.org/r/efde211-f3e2-fe54-977-ef481419e7f3@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Wang Yugui <wangyugui@e16-tech.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Hugh Dickins 2021-06-24 18:39:17 -07:00 committed by Sasha Levin
parent b1783bf8c8
commit a499febd99
1 changed files with 55 additions and 50 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

105
mm/page_vma_mapped.c
View File

@ -168,62 +168,67 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
if (pvmw->pte)
goto next_pte;
restart:
pgd = pgd_offset(mm, pvmw->address);
if (!pgd_present(*pgd))
return false;
p4d = p4d_offset(pgd, pvmw->address);
if (!p4d_present(*p4d))
return false;
pud = pud_offset(p4d, pvmw->address);
if (!pud_present(*pud))
return false;
pvmw->pmd = pmd_offset(pud, pvmw->address);
/*
* Make sure the pmd value isn't cached in a register by the
* compiler and used as a stale value after we've observed a
* subsequent update.
*/
pmde = READ_ONCE(*pvmw->pmd);
if (pmd_trans_huge(pmde) || is_pmd_migration_entry(pmde)) {
pvmw->ptl = pmd_lock(mm, pvmw->pmd);
pmde = *pvmw->pmd;
if (likely(pmd_trans_huge(pmde))) {
if (pvmw->flags & PVMW_MIGRATION)
return not_found(pvmw);
if (pmd_page(pmde) != page)
return not_found(pvmw);
return true;
}
if (!pmd_present(pmde)) {
swp_entry_t entry;
{
pgd = pgd_offset(mm, pvmw->address);
if (!pgd_present(*pgd))
return false;
p4d = p4d_offset(pgd, pvmw->address);
if (!p4d_present(*p4d))
return false;
pud = pud_offset(p4d, pvmw->address);
if (!pud_present(*pud))
return false;
if (!thp_migration_supported() ||
!(pvmw->flags & PVMW_MIGRATION))
return not_found(pvmw);
entry = pmd_to_swp_entry(pmde);
if (!is_migration_entry(entry) ||
migration_entry_to_page(entry) != page)
return not_found(pvmw);
return true;
}
/* THP pmd was split under us: handle on pte level */
spin_unlock(pvmw->ptl);
pvmw->ptl = NULL;
} else if (!pmd_present(pmde)) {
pvmw->pmd = pmd_offset(pud, pvmw->address);
/*
* If PVMW_SYNC, take and drop THP pmd lock so that we
* cannot return prematurely, while zap_huge_pmd() has
* cleared *pmd but not decremented compound_mapcount().
* Make sure the pmd value isn't cached in a register by the
* compiler and used as a stale value after we've observed a
* subsequent update.
*/
if ((pvmw->flags & PVMW_SYNC) && PageTransCompound(page)) {
spinlock_t *ptl = pmd_lock(mm, pvmw->pmd);
pmde = READ_ONCE(*pvmw->pmd);
spin_unlock(ptl);
if (pmd_trans_huge(pmde) || is_pmd_migration_entry(pmde)) {
pvmw->ptl = pmd_lock(mm, pvmw->pmd);
pmde = *pvmw->pmd;
if (likely(pmd_trans_huge(pmde))) {
if (pvmw->flags & PVMW_MIGRATION)
return not_found(pvmw);
if (pmd_page(pmde) != page)
return not_found(pvmw);
return true;
}
if (!pmd_present(pmde)) {
swp_entry_t entry;
if (!thp_migration_supported() ||
!(pvmw->flags & PVMW_MIGRATION))
return not_found(pvmw);
entry = pmd_to_swp_entry(pmde);
if (!is_migration_entry(entry) ||
migration_entry_to_page(entry) != page)
return not_found(pvmw);
return true;
}
/* THP pmd was split under us: handle on pte level */
spin_unlock(pvmw->ptl);
pvmw->ptl = NULL;
} else if (!pmd_present(pmde)) {
/*
* If PVMW_SYNC, take and drop THP pmd lock so that we
* cannot return prematurely, while zap_huge_pmd() has
* cleared *pmd but not decremented compound_mapcount().
*/
if ((pvmw->flags & PVMW_SYNC) &&
PageTransCompound(page)) {
spinlock_t *ptl = pmd_lock(mm, pvmw->pmd);
spin_unlock(ptl);
}
return false;
}
return false;
if (!map_pte(pvmw))
goto next_pte;
}
if (!map_pte(pvmw))
goto next_pte;
while (1) {
unsigned long end;