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authorAdam Litke <agl@us.ibm.com>2007-11-15 03:59:33 +0300
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-11-15 05:45:39 +0300
commit5b23dbe8173c212d6a326e35347b038705603d39 (patch)
treea971d3cbab8911e7cbd5bec66f50d093f3f45976 /mm
parent19cd7537bdae6685c31677a01e08850612ba87f6 (diff)
downloadlinux-5b23dbe8173c212d6a326e35347b038705603d39.tar.xz
hugetlb: follow_hugetlb_page() for write access
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. [ezk@cs.sunysb.edu: build fix] Signed-off-by: Adam Litke <agl@us.ibm.com> Reviewed-by: Ken Chen <kenchen@google.com> Cc: David Gibson <hermes@gibson.dropbear.id.au> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Badari Pulavarty <pbadari@us.ibm.com> Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/hugetlb.c5
-rw-r--r--mm/memory.c2
2 files changed, 4 insertions, 3 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 8b809ecefa39..e2c80631d36a 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -868,7 +868,8 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
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 *mm, struct vm_area_struct *vma,
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 --git a/mm/memory.c b/mm/memory.c
index 9791e4786843..7b0403bfc97f 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1036,7 +1036,7 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
if (is_vm_hugetlb_page(vma)) {
i = follow_hugetlb_page(mm, vma, pages, vmas,
- &start, &len, i);
+ &start, &len, i, write);
continue;
}