[PATCH v4 4/9] mm: Add vmf_insert_pfn_xxx_prot() for huge page-table entries

[Thomas Hellström (VMware)]

From: Thomas Hellstrom <thellstrom at vmware.com>

For graphics drivers needing to modify the page-protection, add
huge page-table entries counterparts to vmf_insert_pfn_prot().

Cc: Andrew Morton <akpm at linux-foundation.org>
Cc: Michal Hocko <mhocko at suse.com>
Cc: "Matthew Wilcox (Oracle)" <willy at infradead.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov at linux.intel.com>
Cc: Ralph Campbell <rcampbell at nvidia.com>
Cc: "Jérôme Glisse" <jglisse at redhat.com>
Cc: "Christian König" <christian.koenig at amd.com>
Cc: Dan Williams <dan.j.williams at intel.com>
Signed-off-by: Thomas Hellstrom <thellstrom at vmware.com>
Acked-by: Christian König <christian.koenig at amd.com>
---
 include/linux/huge_mm.h | 41 +++++++++++++++++++++++++++++++++++++++--
 mm/huge_memory.c        | 38 ++++++++++++++++++++++++++++++++------
 2 files changed, 71 insertions(+), 8 deletions(-)

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 0b84e13e88e2..a95d1bc8ffe8 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -47,8 +47,45 @@ extern bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr,
 extern int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
 			unsigned long addr, pgprot_t newprot,
 			int prot_numa);
-vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, pfn_t pfn, bool write);
-vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn, bool write);
+vm_fault_t vmf_insert_pfn_pmd_prot(struct vm_fault *vmf, pfn_t pfn,
+				   pgprot_t pgprot, bool write);
+
+/**
+ * vmf_insert_pfn_pmd - insert a pmd size pfn
+ * @vmf: Structure describing the fault
+ * @pfn: pfn to insert
+ * @pgprot: page protection to use
+ * @write: whether it's a write fault
+ *
+ * Insert a pmd size pfn. See vmf_insert_pfn() for additional info.
+ *
+ * Return: vm_fault_t value.
+ */
+static inline vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, pfn_t pfn,
+					    bool write)
+{
+	return vmf_insert_pfn_pmd_prot(vmf, pfn, vmf->vma->vm_page_prot, write);
+}
+vm_fault_t vmf_insert_pfn_pud_prot(struct vm_fault *vmf, pfn_t pfn,
+				   pgprot_t pgprot, bool write);
+
+/**
+ * vmf_insert_pfn_pud - insert a pud size pfn
+ * @vmf: Structure describing the fault
+ * @pfn: pfn to insert
+ * @pgprot: page protection to use
+ * @write: whether it's a write fault
+ *
+ * Insert a pud size pfn. See vmf_insert_pfn() for additional info.
+ *
+ * Return: vm_fault_t value.
+ */
+static inline vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn,
+					    bool write)
+{
+	return vmf_insert_pfn_pud_prot(vmf, pfn, vmf->vma->vm_page_prot, write);
+}
+
 enum transparent_hugepage_flag {
 	TRANSPARENT_HUGEPAGE_FLAG,
 	TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index f8d24fc3f4df..b2ec62cca3ae 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -811,11 +811,24 @@ static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
 		pte_free(mm, pgtable);
 }
 
-vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, pfn_t pfn, bool write)
+/**
+ * vmf_insert_pfn_pmd_prot - insert a pmd size pfn
+ * @vmf: Structure describing the fault
+ * @pfn: pfn to insert
+ * @pgprot: page protection to use
+ * @write: whether it's a write fault
+ *
+ * Insert a pmd size pfn. See vmf_insert_pfn() for additional info and
+ * also consult the vmf_insert_mixed_prot() documentation when
+ * @pgprot != @vmf->vma->vm_page_prot.
+ *
+ * Return: vm_fault_t value.
+ */
+vm_fault_t vmf_insert_pfn_pmd_prot(struct vm_fault *vmf, pfn_t pfn,
+				   pgprot_t pgprot, bool write)
 {
 	unsigned long addr = vmf->address & PMD_MASK;
 	struct vm_area_struct *vma = vmf->vma;
-	pgprot_t pgprot = vma->vm_page_prot;
 	pgtable_t pgtable = NULL;
 
 	/*
@@ -843,7 +856,7 @@ vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, pfn_t pfn, bool write)
 	insert_pfn_pmd(vma, addr, vmf->pmd, pfn, pgprot, write, pgtable);
 	return VM_FAULT_NOPAGE;
 }
-EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd);
+EXPORT_SYMBOL_GPL(vmf_insert_pfn_pmd_prot);
 
 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
 static pud_t maybe_pud_mkwrite(pud_t pud, struct vm_area_struct *vma)
@@ -889,11 +902,24 @@ static void insert_pfn_pud(struct vm_area_struct *vma, unsigned long addr,
 	spin_unlock(ptl);
 }
 
-vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn, bool write)
+/**
+ * vmf_insert_pfn_pud_prot - insert a pud size pfn
+ * @vmf: Structure describing the fault
+ * @pfn: pfn to insert
+ * @pgprot: page protection to use
+ * @write: whether it's a write fault
+ *
+ * Insert a pud size pfn. See vmf_insert_pfn() for additional info and
+ * also consult the vmf_insert_mixed_prot() documentation when
+ * @pgprot != @vmf->vma->vm_page_prot.
+ *
+ * Return: vm_fault_t value.
+ */
+vm_fault_t vmf_insert_pfn_pud_prot(struct vm_fault *vmf, pfn_t pfn,
+				   pgprot_t pgprot, bool write)
 {
 	unsigned long addr = vmf->address & PUD_MASK;
 	struct vm_area_struct *vma = vmf->vma;
-	pgprot_t pgprot = vma->vm_page_prot;
 
 	/*
 	 * If we had pud_special, we could avoid all these restrictions,
@@ -914,7 +940,7 @@ vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn, bool write)
 	insert_pfn_pud(vma, addr, vmf->pud, pfn, pgprot, write);
 	return VM_FAULT_NOPAGE;
 }
-EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud);
+EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud_prot);
 #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 
 static void touch_pmd(struct vm_area_struct *vma, unsigned long addr,
-- 
2.21.1