The patch titled
Subject: mm: ptep_clear() page table helper
has been removed from the -mm tree. Its filename was
mm-ptep_clear-page-table-helper.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
Subject: mm: ptep_clear() page table helper
We have ptep_get_and_clear() and ptep_get_and_clear_full() helpers to
clear PTE from user page tables, but there is no variant for simple clear
of a present PTE from user page tables without using a low level
pte_clear() which can be either native or para-virtualised.
Add a new ptep_clear() that can be used in common code to clear PTEs from
page table. We will need this call later in order to add a hook for page
table check.
Link: https://lkml.kernel.org/r/20211221154650.1047963-3-pasha.tatashin@xxxxxxxxxx
Signed-off-by: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Frederic Weisbecker <frederic@xxxxxxxxxx>
Cc: Greg Thelen <gthelen@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jiri Slaby <jirislaby@xxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Masahiro Yamada <masahiroy@xxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxx>
Cc: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Cc: Paul Turner <pjt@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Sami Tolvanen <samitolvanen@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Wei Xu <weixugc@xxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/vm/arch_pgtable_helpers.rst | 6 ++++--
include/linux/pgtable.h | 8 ++++++++
mm/debug_vm_pgtable.c | 2 +-
mm/khugepaged.c | 12 ++----------
4 files changed, 15 insertions(+), 13 deletions(-)
--- a/Documentation/vm/arch_pgtable_helpers.rst~mm-ptep_clear-page-table-helper
+++ a/Documentation/vm/arch_pgtable_helpers.rst
@@ -66,9 +66,11 @@ PTE Page Table Helpers
+---------------------------+--------------------------------------------------+
| pte_mknotpresent | Invalidates a mapped PTE |
+---------------------------+--------------------------------------------------+
-| ptep_get_and_clear | Clears a PTE |
+| ptep_clear | Clears a PTE |
+---------------------------+--------------------------------------------------+
-| ptep_get_and_clear_full | Clears a PTE |
+| ptep_get_and_clear | Clears and returns PTE |
++---------------------------+--------------------------------------------------+
+| ptep_get_and_clear_full | Clears and returns PTE (batched PTE unmap) |
+---------------------------+--------------------------------------------------+
| ptep_test_and_clear_young | Clears young from a PTE |
+---------------------------+--------------------------------------------------+
--- a/include/linux/pgtable.h~mm-ptep_clear-page-table-helper
+++ a/include/linux/pgtable.h
@@ -258,6 +258,14 @@ static inline int pmdp_clear_flush_young
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif
+#ifndef __HAVE_ARCH_PTEP_CLEAR
+static inline void ptep_clear(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep)
+{
+ pte_clear(mm, addr, ptep);
+}
+#endif
+
#ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
static inline pte_t ptep_get_and_clear(struct mm_struct *mm,
unsigned long address,
--- a/mm/debug_vm_pgtable.c~mm-ptep_clear-page-table-helper
+++ a/mm/debug_vm_pgtable.c
@@ -652,7 +652,7 @@ static void __init pte_clear_tests(struc
set_pte_at(args->mm, args->vaddr, args->ptep, pte);
flush_dcache_page(page);
barrier();
- pte_clear(args->mm, args->vaddr, args->ptep);
+ ptep_clear(args->mm, args->vaddr, args->ptep);
pte = ptep_get(args->ptep);
WARN_ON(!pte_none(pte));
}
--- a/mm/khugepaged.c~mm-ptep_clear-page-table-helper
+++ a/mm/khugepaged.c
@@ -756,11 +756,7 @@ static void __collapse_huge_page_copy(pt
* ptl mostly unnecessary.
*/
spin_lock(ptl);
- /*
- * paravirt calls inside pte_clear here are
- * superfluous.
- */
- pte_clear(vma->vm_mm, address, _pte);
+ ptep_clear(vma->vm_mm, address, _pte);
spin_unlock(ptl);
}
} else {
@@ -774,11 +770,7 @@ static void __collapse_huge_page_copy(pt
* inside page_remove_rmap().
*/
spin_lock(ptl);
- /*
- * paravirt calls inside pte_clear here are
- * superfluous.
- */
- pte_clear(vma->vm_mm, address, _pte);
+ ptep_clear(vma->vm_mm, address, _pte);
page_remove_rmap(src_page, false);
spin_unlock(ptl);
free_page_and_swap_cache(src_page);
_
Patches currently in -mm which might be from pasha.tatashin@xxxxxxxxxx are
