The patch titled
hugetlb: follow_hugetlb_page() for write access
has been added to the -mm tree. Its filename is
hugetlb-follow_hugetlb_page-for-write-access.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: hugetlb: follow_hugetlb_page() for write access
From: Adam Litke <agl@xxxxxxxxxx>
When calling get_user_pages(), a write flag is passed in by the caller to
indicate if write access is required on the faulted-in pages. Currently,
follow_hugetlb_page() ignores this flag and always faults pages for
read-only access. This can cause data corruption because a device driver
that calls get_user_pages() with write set will not expect COW faults to
occur on the returned pages.
This patch passes the write flag down to follow_hugetlb_page() and makes
sure hugetlb_fault() is called with the right write_access parameter.
Signed-off-by: Adam Litke <agl@xxxxxxxxxx>
Reviewed-by: Ken Chen <kenchen@xxxxxxxxxx>
Cc: David Gibson <hermes@xxxxxxxxxxxxxxxxxxxxx>
Cc: William Lee Irwin III <wli@xxxxxxxxxxxxxx>
Cc: Badari Pulavarty <pbadari@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/hugetlb.h | 2 +-
mm/hugetlb.c | 5 +++--
mm/memory.c | 2 +-
3 files changed, 5 insertions(+), 4 deletions(-)
diff -puN include/linux/hugetlb.h~hugetlb-follow_hugetlb_page-for-write-access include/linux/hugetlb.h
--- a/include/linux/hugetlb.h~hugetlb-follow_hugetlb_page-for-write-access
+++ a/include/linux/hugetlb.h
@@ -19,7 +19,7 @@ static inline int is_vm_hugetlb_page(str
int hugetlb_sysctl_handler(struct ctl_table *, int, struct file *, void __user *, size_t *, loff_t *);
int hugetlb_treat_movable_handler(struct ctl_table *, int, struct file *, void __user *, size_t *, loff_t *);
int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *, struct vm_area_struct *);
-int follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *, struct page **, struct vm_area_struct **, unsigned long *, int *, int);
+int follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *, struct page **, struct vm_area_struct **, unsigned long *, int *, int, int);
void unmap_hugepage_range(struct vm_area_struct *, unsigned long, unsigned long);
void __unmap_hugepage_range(struct vm_area_struct *, unsigned long, unsigned long);
int hugetlb_prefault(struct address_space *, struct vm_area_struct *);
diff -puN mm/hugetlb.c~hugetlb-follow_hugetlb_page-for-write-access mm/hugetlb.c
--- a/mm/hugetlb.c~hugetlb-follow_hugetlb_page-for-write-access
+++ a/mm/hugetlb.c
@@ -868,7 +868,8 @@ int hugetlb_fault(struct mm_struct *mm,
int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
struct page **pages, struct vm_area_struct **vmas,
- unsigned long *position, int *length, int i)
+ unsigned long *position, int *length, int i,
+ int write)
{
unsigned long pfn_offset;
unsigned long vaddr = *position;
@@ -890,7 +891,7 @@ int follow_hugetlb_page(struct mm_struct
int ret;
spin_unlock(&mm->page_table_lock);
- ret = hugetlb_fault(mm, vma, vaddr, 0);
+ ret = hugetlb_fault(mm, vma, vaddr, write);
spin_lock(&mm->page_table_lock);
if (!(ret & VM_FAULT_ERROR))
continue;
diff -puN mm/memory.c~hugetlb-follow_hugetlb_page-for-write-access mm/memory.c
--- a/mm/memory.c~hugetlb-follow_hugetlb_page-for-write-access
+++ a/mm/memory.c
@@ -1036,7 +1036,7 @@ int get_user_pages(struct task_struct *t
if (is_vm_hugetlb_page(vma)) {
i = follow_hugetlb_page(mm, vma, pages, vmas,
- &start, &len, i);
+ &start, &len, i, write);
continue;
}
_
Patches currently in -mm which might be from agl@xxxxxxxxxx are
hugetlb-follow_hugetlb_page-for-write-access.patch
hugetlb-allow-sticky-directory-mount-option.patch
hugetlb-split-alloc_huge_page-into-private-and-shared-components.patch
hugetlb-split-alloc_huge_page-into-private-and-shared-components-checkpatch-fixes.patch
hugetlb-fix-quota-management-for-private-mappings.patch
hugetlb-debit-quota-in-alloc_huge_page.patch
hugetlb-allow-bulk-updating-in-hugetlb__quota.patch
hugetlb-enforce-quotas-during-reservation-for-shared-mappings.patch
mm-hugetlbc-make-a-function-static.patch
-
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