linux-kernel - [PATCH v5 13/13] mm: pgtable: remove pte_offset_map

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Message-Id: <d04f9bbbcde048fb6ffa6f2bdbc6f9b22d5286f9.1727332572.git.zhengqi.arch@bytedance.com>
Date: Thu, 26 Sep 2024 14:46:26 +0800
From: Qi Zheng <zhengqi.arch@...edance.com>
To: david@...hat.com,
	hughd@...gle.com,
	willy@...radead.org,
	muchun.song@...ux.dev,
	vbabka@...nel.org,
	akpm@...ux-foundation.org,
	rppt@...nel.org,
	vishal.moola@...il.com,
	peterx@...hat.com,
	ryan.roberts@....com,
	christophe.leroy2@...soprasteria.com
Cc: linux-kernel@...r.kernel.org,
	linux-mm@...ck.org,
	linux-arm-kernel@...ts.infradead.org,
	linuxppc-dev@...ts.ozlabs.org,
	Qi Zheng <zhengqi.arch@...edance.com>
Subject: [PATCH v5 13/13] mm: pgtable: remove pte_offset_map_nolock()

Now no users are using the pte_offset_map_nolock(), remove it.

Signed-off-by: Qi Zheng <zhengqi.arch@...edance.com>
Reviewed-by: Muchun Song <muchun.song@...ux.dev>
Acked-by: David Hildenbrand <david@...hat.com>
---
 Documentation/mm/split_page_table_lock.rst |  3 ---
 include/linux/mm.h                         |  2 --
 mm/pgtable-generic.c                       | 21 ---------------------
 3 files changed, 26 deletions(-)

diff --git a/Documentation/mm/split_page_table_lock.rst b/Documentation/mm/split_page_table_lock.rst
index 08d0e706a32db..581446d4a4eba 100644
--- a/Documentation/mm/split_page_table_lock.rst
+++ b/Documentation/mm/split_page_table_lock.rst
@@ -16,9 +16,6 @@ There are helpers to lock/unlock a table and other accessor functions:
  - pte_offset_map_lock()
 	maps PTE and takes PTE table lock, returns pointer to PTE with
 	pointer to its PTE table lock, or returns NULL if no PTE table;
- - pte_offset_map_nolock()
-	maps PTE, returns pointer to PTE with pointer to its PTE table
-	lock (not taken), or returns NULL if no PTE table;
  - pte_offset_map_ro_nolock()
 	maps PTE, returns pointer to PTE with pointer to its PTE table
 	lock (not taken), or returns NULL if no PTE table;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 46828b9a74f2c..60a55b28cf679 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3015,8 +3015,6 @@ static inline pte_t *pte_offset_map_lock(struct mm_struct *mm, pmd_t *pmd,
 	return pte;
 }
 
-pte_t *pte_offset_map_nolock(struct mm_struct *mm, pmd_t *pmd,
-			unsigned long addr, spinlock_t **ptlp);
 pte_t *pte_offset_map_ro_nolock(struct mm_struct *mm, pmd_t *pmd,
 				unsigned long addr, spinlock_t **ptlp);
 pte_t *pte_offset_map_rw_nolock(struct mm_struct *mm, pmd_t *pmd,
diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index daa08b91ab6b2..5297dcc38c37a 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -305,18 +305,6 @@ pte_t *__pte_offset_map(pmd_t *pmd, unsigned long addr, pmd_t *pmdvalp)
 	return NULL;
 }
 
-pte_t *pte_offset_map_nolock(struct mm_struct *mm, pmd_t *pmd,
-			     unsigned long addr, spinlock_t **ptlp)
-{
-	pmd_t pmdval;
-	pte_t *pte;
-
-	pte = __pte_offset_map(pmd, addr, &pmdval);
-	if (likely(pte))
-		*ptlp = pte_lockptr(mm, &pmdval);
-	return pte;
-}
-
 pte_t *pte_offset_map_ro_nolock(struct mm_struct *mm, pmd_t *pmd,
 				unsigned long addr, spinlock_t **ptlp)
 {
@@ -372,15 +360,6 @@ pte_t *pte_offset_map_rw_nolock(struct mm_struct *mm, pmd_t *pmd,
  * and disconnected table.  Until pte_unmap(pte) unmaps and rcu_read_unlock()s
  * afterwards.
  *
- * 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.
- *
  * pte_offset_map_ro_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
-- 
2.20.1