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authorAdam Litke <agl@us.ibm.com>2007-11-14 19:59:33 -0500
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-11-14 21:45:39 -0500
commit5b23dbe8173c212d6a326e35347b038705603d39 (patch)
treea971d3cbab8911e7cbd5bec66f50d093f3f45976 /mm/hugetlb.c
parent19cd7537bdae6685c31677a01e08850612ba87f6 (diff)
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/hugetlb.c')
-rw-r--r--mm/hugetlb.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 8b809ecefa3..e2c80631d36 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,
868 868
869int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, 869int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
870 struct page **pages, struct vm_area_struct **vmas, 870 struct page **pages, struct vm_area_struct **vmas,
871 unsigned long *position, int *length, int i) 871 unsigned long *position, int *length, int i,
872 int write)
872{ 873{
873 unsigned long pfn_offset; 874 unsigned long pfn_offset;
874 unsigned long vaddr = *position; 875 unsigned long vaddr = *position;
@@ -890,7 +891,7 @@ int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
890 int ret; 891 int ret;
891 892
892 spin_unlock(&mm->page_table_lock); 893 spin_unlock(&mm->page_table_lock);
893 ret = hugetlb_fault(mm, vma, vaddr, 0); 894 ret = hugetlb_fault(mm, vma, vaddr, write);
894 spin_lock(&mm->page_table_lock); 895 spin_lock(&mm->page_table_lock);
895 if (!(ret & VM_FAULT_ERROR)) 896 if (!(ret & VM_FAULT_ERROR))
896 continue; 897 continue;