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From:   Ryan Roberts <ryan.roberts@arm.com>
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Cc:     Ryan Roberts <ryan.roberts@arm.com>, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, damon@lists.linux.dev
Subject: [PATCH v3 2/3] mm: Move ptep_get() and pmdp_get() helpers
Date:   Mon, 12 Jun 2023 16:15:44 +0100
Message-Id: <20230612151545.3317766-3-ryan.roberts@arm.com>
In-Reply-To: <20230612151545.3317766-1-ryan.roberts@arm.com>
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There are many call sites that directly dereference a pte_t pointer.
This makes it very difficult to properly encapsulate a page table in the
arch code without having to allocate shadow page tables.

We will shortly solve this by replacing all the call sites with
ptep_get() calls. But there are call sites above the function definition
in the header file, so let's move ptep_get() to an earlier location to
solve that problem. And move pmdp_get() at the same time to keep it
close to ptep_get().

Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
---
 include/linux/pgtable.h | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index a1326e61d7ee..fc06f6419661 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -212,6 +212,20 @@ static inline int pudp_set_access_flags(struct vm_area_struct *vma,
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 #endif
 
+#ifndef ptep_get
+static inline pte_t ptep_get(pte_t *ptep)
+{
+	return READ_ONCE(*ptep);
+}
+#endif
+
+#ifndef pmdp_get
+static inline pmd_t pmdp_get(pmd_t *pmdp)
+{
+	return READ_ONCE(*pmdp);
+}
+#endif
+
 #ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
 static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
 					    unsigned long address,
@@ -317,20 +331,6 @@ static inline void ptep_clear(struct mm_struct *mm, unsigned long addr,
 	ptep_get_and_clear(mm, addr, ptep);
 }
 
-#ifndef ptep_get
-static inline pte_t ptep_get(pte_t *ptep)
-{
-	return READ_ONCE(*ptep);
-}
-#endif
-
-#ifndef pmdp_get
-static inline pmd_t pmdp_get(pmd_t *pmdp)
-{
-	return READ_ONCE(*pmdp);
-}
-#endif
-
 #ifdef CONFIG_GUP_GET_PXX_LOW_HIGH
 /*
  * For walking the pagetables without holding any locks.  Some architectures
-- 
2.25.1