linux-kernel - [PATCH v4 05/36] mm: Add default definition of set

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Message-Id: <20230315051444.3229621-6-willy@infradead.org>
Date:   Wed, 15 Mar 2023 05:14:13 +0000
From:   "Matthew Wilcox (Oracle)" <willy@...radead.org>
To:     linux-arch@...r.kernel.org
Cc:     "Matthew Wilcox (Oracle)" <willy@...radead.org>,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Mike Rapoport <rppt@...nel.org>
Subject: [PATCH v4 05/36] mm: Add default definition of set_ptes()

Most architectures can just define set_pte() and PFN_PTE_SHIFT to
use this definition.  It's also a handy spot to document the guarantees
provided by the MM.

Suggested-by: Mike Rapoport (IBM) <rppt@...nel.org>
Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
---
 include/linux/pgtable.h | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index c5a51481bbb9..a755fe94b4b4 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -172,6 +172,43 @@ static inline int pmd_young(pmd_t pmd)
 }
 #endif
 
+#ifndef set_ptes
+#ifdef PFN_PTE_SHIFT
+/**
+ * set_ptes - Map consecutive pages to a contiguous range of addresses.
+ * @mm: Address space to map the pages into.
+ * @addr: Address to map the first page at.
+ * @ptep: Page table pointer for the first entry.
+ * @pte: Page table entry for the first page.
+ * @nr: Number of pages to map.
+ *
+ * May be overridden by the architecture, or the architecture can define
+ * set_pte() and PFN_PTE_SHIFT.
+ *
+ * Context: The caller holds the page table lock.  The pages all belong
+ * to the same folio.  The PTEs are all in the same PMD.
+ */
+static inline void set_ptes(struct mm_struct *mm, unsigned long addr,
+		pte_t *ptep, pte_t pte, unsigned int nr)
+{
+	page_table_check_ptes_set(mm, addr, ptep, pte, nr);
+
+	for (;;) {
+		set_pte(ptep, pte);
+		if (--nr == 0)
+			break;
+		ptep++;
+		pte = __pte(pte_val(pte) + (1UL << PFN_PTE_SHIFT));
+	}
+}
+#ifndef set_pte_at
+#define set_pte_at(mm, addr, ptep, pte) set_ptes(mm, addr, ptep, pte, 1)
+#endif
+#endif
+#else
+#define set_pte_at(mm, addr, ptep, pte) set_ptes(mm, addr, ptep, pte, 1)
+#endif
+
 #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
 extern int ptep_set_access_flags(struct vm_area_struct *vma,
 				 unsigned long address, pte_t *ptep,
-- 
2.39.2