From: Matthew Wilcox <wi...@linux.intel.com>
vm_insert_mixed() will fail if there is already a valid PTE at that
location. The DAX code would rather replace the previous value with
the new PTE.
Signed-off-by: Matthew Wilcox <wi...@linux.intel.com>
---
include/linux/mm.h | 8 ++++++--
mm/memory.c | 34 +++++++++++++++++++++-------------
2 files changed, 27 insertions(+), 15 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e04f531..8d1194c 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1958,8 +1958,12 @@ int remap_pfn_range(struct vm_area_struct *, unsigned
long addr,
int vm_insert_page(struct vm_area_struct *, unsigned long addr, struct page *);
int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
unsigned long pfn);
-int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
- unsigned long pfn);
+int __vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
+ unsigned long pfn, bool replace);
+#define vm_insert_mixed(vma, addr, pfn) \
+ __vm_insert_mixed(vma, addr, pfn, false)
+#define vm_replace_mixed(vma, addr, pfn) \
+ __vm_insert_mixed(vma, addr, pfn, true)
int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned
long len);
diff --git a/mm/memory.c b/mm/memory.c
index 42bf429..cf06c97 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1476,7 +1476,7 @@ pte_t *__get_locked_pte(struct mm_struct *mm, unsigned
long addr,
* pages reserved for the old functions anyway.
*/
static int insert_page(struct vm_area_struct *vma, unsigned long addr,
- struct page *page, pgprot_t prot)
+ struct page *page, pgprot_t prot, bool replace)
{
struct mm_struct *mm = vma->vm_mm;
int retval;
@@ -1492,8 +1492,12 @@ static int insert_page(struct vm_area_struct *vma,
unsigned long addr,
if (!pte)
goto out;
retval = -EBUSY;
- if (!pte_none(*pte))
- goto out_unlock;
+ if (!pte_none(*pte)) {
+ if (!replace)
+ goto out_unlock;
+
VM_BUG_ON(!mutex_is_locked(&vma->vm_file->f_mapping->i_mmap_mutex));
+ zap_page_range_single(vma, addr, PAGE_SIZE, NULL);
+ }
/* Ok, finally just insert the thing.. */
get_page(page);
@@ -1549,12 +1553,12 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned
long addr,
BUG_ON(vma->vm_flags & VM_PFNMAP);
vma->vm_flags |= VM_MIXEDMAP;
}
- return insert_page(vma, addr, page, vma->vm_page_prot);
+ return insert_page(vma, addr, page, vma->vm_page_prot, false);
}
EXPORT_SYMBOL(vm_insert_page);
static int insert_pfn(struct vm_area_struct *vma, unsigned long addr,
- unsigned long pfn, pgprot_t prot)
+ unsigned long pfn, pgprot_t prot, bool replace)
{
struct mm_struct *mm = vma->vm_mm;
int retval;
@@ -1566,8 +1570,12 @@ static int insert_pfn(struct vm_area_struct *vma,
unsigned long addr,
if (!pte)
goto out;
retval = -EBUSY;
- if (!pte_none(*pte))
- goto out_unlock;
+ if (!pte_none(*pte)) {
+ if (!replace)
+ goto out_unlock;
+
VM_BUG_ON(!mutex_is_locked(&vma->vm_file->f_mapping->i_mmap_mutex));
+ zap_page_range_single(vma, addr, PAGE_SIZE, NULL);
+ }
/* Ok, finally just insert the thing.. */
entry = pte_mkspecial(pfn_pte(pfn, prot));
@@ -1620,14 +1628,14 @@ int vm_insert_pfn(struct vm_area_struct *vma, unsigned
long addr,
if (track_pfn_insert(vma, &pgprot, pfn))
return -EINVAL;
- ret = insert_pfn(vma, addr, pfn, pgprot);
+ ret = insert_pfn(vma, addr, pfn, pgprot, false);
return ret;
}
EXPORT_SYMBOL(vm_insert_pfn);
-int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
- unsigned long pfn)
+int __vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
+ unsigned long pfn, bool replace)
{
BUG_ON(!(vma->vm_flags & VM_MIXEDMAP));
@@ -1645,11 +1653,11 @@ int vm_insert_mixed(struct vm_area_struct *vma,
unsigned long addr,
struct page *page;
page = pfn_to_page(pfn);
- return insert_page(vma, addr, page, vma->vm_page_prot);
+ return insert_page(vma, addr, page, vma->vm_page_prot, replace);
}
- return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
+ return insert_pfn(vma, addr, pfn, vma->vm_page_prot, replace);
}
-EXPORT_SYMBOL(vm_insert_mixed);
+EXPORT_SYMBOL(__vm_insert_mixed);
/*
* maps a range of physical memory into the requested pages. the old
--
2.0.0
--
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