[PATCH 08/13] mm/huge_memory: add helpers to insert huge page during mmap

[Hou Tao]

From: Hou Tao <houtao1 at huawei.com>

vmf_insert_folio_{pmd,pud}() can be used to insert huge page during page
fault. However, for simplicity, the mapping of p2pdma memory inserts all
necessary pages during mmap. Therefore, add vm_insert_folio_{pmd|pud}
helpers to support inserting pmd-sized and pud-sized page during mmap.

Signed-off-by: Hou Tao <houtao1 at huawei.com>
---
 include/linux/huge_mm.h |  4 +++
 mm/huge_memory.c        | 66 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 70 insertions(+)

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index a4d9f964dfde..8cf8bb85be79 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -45,6 +45,10 @@ vm_fault_t vmf_insert_folio_pmd(struct vm_fault *vmf, struct folio *folio,
 				bool write);
 vm_fault_t vmf_insert_folio_pud(struct vm_fault *vmf, struct folio *folio,
 				bool write);
+int vm_insert_folio_pmd(struct vm_area_struct *vma, unsigned long addr,
+			struct folio *folio);
+int vm_insert_folio_pud(struct vm_area_struct *vma, unsigned long addr,
+			struct folio *folio);
 
 enum transparent_hugepage_flag {
 	TRANSPARENT_HUGEPAGE_UNSUPPORTED,
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 40cf59301c21..11d19f8986da 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1644,6 +1644,41 @@ vm_fault_t vmf_insert_folio_pmd(struct vm_fault *vmf, struct folio *folio,
 }
 EXPORT_SYMBOL_GPL(vmf_insert_folio_pmd);
 
+int vm_insert_folio_pmd(struct vm_area_struct *vma, unsigned long addr,
+			struct folio *folio)
+{
+	struct mm_struct *mm = vma->vm_mm;
+	struct folio_or_pfn fop = {
+		.folio = folio,
+		.is_folio = true,
+	};
+	pgd_t *pgd;
+	p4d_t *p4d;
+	pud_t *pud;
+	pmd_t *pmd;
+	vm_fault_t fault_err;
+
+	mmap_assert_write_locked(mm);
+
+	pgd = pgd_offset(mm, addr);
+	p4d = p4d_alloc(mm, pgd, addr);
+	if (!p4d)
+		return -ENOMEM;
+	pud = pud_alloc(mm, p4d, addr);
+	if (!pud)
+		return -ENOMEM;
+	pmd = pmd_alloc(mm, pud, addr);
+	if (!pmd)
+		return -ENOMEM;
+
+	fault_err = insert_pmd(vma, addr, pmd, fop, vma->vm_page_prot,
+			       vma->vm_flags & VM_WRITE);
+	if (fault_err != VM_FAULT_NOPAGE)
+		return -EINVAL;
+
+	return 0;
+}
+
 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
 static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma)
 {
@@ -1759,6 +1794,37 @@ vm_fault_t vmf_insert_folio_pud(struct vm_fault *vmf, struct folio *folio,
 	return insert_pud(vma, addr, vmf->pud, fop, vma->vm_page_prot, write);
 }
 EXPORT_SYMBOL_GPL(vmf_insert_folio_pud);
+
+int vm_insert_folio_pud(struct vm_area_struct *vma, unsigned long addr,
+			struct folio *folio)
+{
+	struct mm_struct *mm = vma->vm_mm;
+	struct folio_or_pfn fop = {
+		.folio = folio,
+		.is_folio = true,
+	};
+	pgd_t *pgd;
+	p4d_t *p4d;
+	pud_t *pud;
+	vm_fault_t fault_err;
+
+	mmap_assert_write_locked(mm);
+
+	pgd = pgd_offset(mm, addr);
+	p4d = p4d_alloc(mm, pgd, addr);
+	if (!p4d)
+		return -ENOMEM;
+	pud = pud_alloc(mm, p4d, addr);
+	if (!pud)
+		return -ENOMEM;
+
+	fault_err = insert_pud(vma, addr, pud, fop, vma->vm_page_prot,
+			       vma->vm_flags & VM_WRITE);
+	if (fault_err != VM_FAULT_NOPAGE)
+		return -EINVAL;
+
+	return 0;
+}
 #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 
 /**
-- 
2.29.2