The patch titled
Subject: mm-let-pte_lockptr-consume-a-pte_t-pointer-fix
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-let-pte_lockptr-consume-a-pte_t-pointer-fix.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-let-pte_lockptr-consume-a-pte_t-pointer-fix.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: David Hildenbrand <david@xxxxxxxxxx>
Subject: mm-let-pte_lockptr-consume-a-pte_t-pointer-fix
Date: Mon, 29 Jul 2024 10:43:34 +0200
Let's adjust the comment, passing a pte to pte_lockptr() and dropping
a detail about changed *pmd, which no longer applies.
Link: https://lkml.kernel.org/r/498c936f-fa30-4670-9bbc-4cd8b7995091@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/pgtable-generic.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
--- a/mm/pgtable-generic.c~mm-let-pte_lockptr-consume-a-pte_t-pointer-fix
+++ a/mm/pgtable-generic.c
@@ -350,11 +350,11 @@ pte_t *pte_offset_map_nolock(struct mm_s
* pte_offset_map_nolock(mm, pmd, addr, ptlp), above, is like pte_offset_map();
* but when successful, it also outputs a pointer to the spinlock in ptlp - as
* pte_offset_map_lock() does, but in this case without locking it. This helps
- * the caller to avoid a later pte_lockptr(mm, *pmd), which might by that time
- * act on a changed *pmd: pte_offset_map_nolock() provides the correct spinlock
- * pointer for the page table that it returns. In principle, the caller should
- * recheck *pmd once the lock is taken; in practice, no callsite needs that -
- * either the mmap_lock for write, or pte_same() check on contents, is enough.
+ * the caller to avoid a later pte_lockptr(mm, pte): pte_offset_map_nolock()
+ * provides the correct spinlock pointer for the page table that it returns.
+ * In principle, the caller should recheck *pmd once the lock is taken; in
+ * practice, no callsite needs that - either the mmap_lock for write, or
+ * pte_same() check on contents, is enough.
*
* Note that free_pgtables(), used after unmapping detached vmas, or when
* exiting the whole mm, does not take page table lock before freeing a page
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
mm-let-pte_lockptr-consume-a-pte_t-pointer.patch
mm-let-pte_lockptr-consume-a-pte_t-pointer-fix.patch
mm-hugetlb-fix-hugetlb-vs-core-mm-pt-locking.patch
mm-turn-use_split_pte_ptlocks-use_split_pte_ptlocks-into-kconfig-options.patch
mm-hugetlb-enforce-that-pmd-pt-sharing-has-split-pmd-pt-locks.patch
powerpc-8xx-document-and-enforce-that-split-pt-locks-are-not-used.patch
mm-simplify-arch_make_folio_accessible.patch
mm-gup-convert-to-arch_make_folio_accessible.patch
s390-uv-drop-arch_make_page_accessible.patch
