[PATCH 1/3] mm: Introduce vmf_insert_pfn_prot

From: Matthew Wilcox
Date: Tue Jul 03 2018 - 08:39:46 EST


Like vm_insert_pfn_prot(), but returns a vm_fault_t instead of an errno.
Also unexport vm_insert_pfn_prot as it has no modular users.

Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxx>
---
include/linux/mm.h | 2 ++
mm/memory.c | 47 ++++++++++++++++++++++++++++++----------------
2 files changed, 33 insertions(+), 16 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1a9d6bd97f00..3cb763a38642 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2441,6 +2441,8 @@ int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
unsigned long pfn);
int vm_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr,
unsigned long pfn, pgprot_t pgprot);
+vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr,
+ unsigned long pfn, pgprot_t pgprot);
int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
pfn_t pfn);
vm_fault_t vmf_insert_mixed_mkwrite(struct vm_area_struct *vma,
diff --git a/mm/memory.c b/mm/memory.c
index b9ebd883e27c..caecb4d995ac 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1852,21 +1852,6 @@ int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
}
EXPORT_SYMBOL(vm_insert_pfn);

-/**
- * vm_insert_pfn_prot - insert single pfn into user vma with specified pgprot
- * @vma: user vma to map to
- * @addr: target user address of this page
- * @pfn: source kernel pfn
- * @pgprot: pgprot flags for the inserted page
- *
- * This is exactly like vm_insert_pfn, except that it allows drivers to
- * to override pgprot on a per-page basis.
- *
- * This only makes sense for IO mappings, and it makes no sense for
- * cow mappings. In general, using multiple vmas is preferable;
- * vm_insert_pfn_prot should only be used if using multiple VMAs is
- * impractical.
- */
int vm_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr,
unsigned long pfn, pgprot_t pgprot)
{
@@ -1893,7 +1878,37 @@ int vm_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr,

return ret;
}
-EXPORT_SYMBOL(vm_insert_pfn_prot);
+
+/**
+ * vmf_insert_pfn_prot - insert single pfn into user vma with specified pgprot
+ * @vma: user vma to map to
+ * @addr: target user address of this page
+ * @pfn: source kernel pfn
+ * @pgprot: pgprot flags for the inserted page
+ *
+ * This is exactly like vmf_insert_pfn(), except that it allows drivers to
+ * to override pgprot on a per-page basis.
+ *
+ * This only makes sense for IO mappings, and it makes no sense for
+ * COW mappings. In general, using multiple vmas is preferable;
+ * vm_insert_pfn_prot should only be used if using multiple VMAs is
+ * impractical.
+ *
+ * Return: vm_fault_t value.
+ */
+vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr,
+ unsigned long pfn, pgprot_t pgprot)
+{
+ int err = vm_insert_pfn_prot(vma, addr, pfn, pgprot);
+
+ if (err == -ENOMEM)
+ return VM_FAULT_OOM;
+ if (err < 0 && err != -EBUSY)
+ return VM_FAULT_SIGBUS;
+
+ return VM_FAULT_NOPAGE;
+}
+EXPORT_SYMBOL(vmf_insert_pfn_prot);

static bool vm_mixed_ok(struct vm_area_struct *vma, pfn_t pfn)
{
--
2.18.0