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From:   Liam Howlett <liam.howlett@oracle.com>
To:     "maple-tree@lists.infradead.org" <maple-tree@lists.infradead.org>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>,
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        Rik van Riel <riel@surriel.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Michel Lespinasse <walken.cr@gmail.com>,
        Liam Howlett <liam.howlett@oracle.com>
Subject: [PATCH 38/94] mm/gup: Add mm_populate_vma() for use when the vma is
 known
Thread-Topic: [PATCH 38/94] mm/gup: Add mm_populate_vma() for use when the vma
 is known
Thread-Index: AQHXPEQ1vRs0vBrIxUqHuI8bmYeYEQ==
Date:   Wed, 28 Apr 2021 15:36:08 +0000
Message-ID: <20210428153542.2814175-39-Liam.Howlett@Oracle.com>
References: <20210428153542.2814175-1-Liam.Howlett@Oracle.com>
In-Reply-To: <20210428153542.2814175-1-Liam.Howlett@Oracle.com>
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When a vma is known, avoid calling mm_populate to search for the vma to
populate.

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
---
 mm/gup.c      | 20 ++++++++++++++++++++
 mm/internal.h |  4 ++++
 2 files changed, 24 insertions(+)

diff --git a/mm/gup.c b/mm/gup.c
index c3a17b189064..48fe98ab0729 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1468,6 +1468,26 @@ long populate_vma_page_range(struct vm_area_struct *=
vma,
 				NULL, NULL, locked);
 }
=20
+/*
+ * mm_populate_vma() - Populate a single range in a single vma.
+ * @vma: The vma to populate.
+ * @start: The start address to populate
+ * @end: The end address to stop populating
+ *
+ * Note: Ignores errors.
+ */
+void mm_populate_vma(struct vm_area_struct *vma, unsigned long start,
+		unsigned long end)
+{
+	struct mm_struct *mm =3D current->mm;
+	int locked =3D 1;
+
+	mmap_read_lock(mm);
+	populate_vma_page_range(vma, start, end, &locked);
+	if (locked)
+		mmap_read_unlock(mm);
+}
+
 /*
  * __mm_populate - populate and/or mlock pages within a range of address s=
pace.
  *
diff --git a/mm/internal.h b/mm/internal.h
index 7ad55938d391..583f2f1e6ff8 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -346,6 +346,10 @@ static inline bool is_data_mapping(vm_flags_t flags)
 	return (flags & (VM_WRITE | VM_SHARED | VM_STACK)) =3D=3D VM_WRITE;
 }
=20
+/* mm/gup.c */
+extern void mm_populate_vma(struct vm_area_struct *vma, unsigned long star=
t,
+			    unsigned long end);
+
 /* Maple tree operations using VMAs */
 /*
  * vma_mas_store() - Store a VMA in the maple tree.
--=20
2.30.2