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| author | Adam Litke <agl@us.ibm.com> | 2007-11-14 16:59:33 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-11-14 18:45:39 -0800 |
| commit | 5b23dbe8173c212d6a326e35347b038705603d39 (patch) | |
| tree | a971d3cbab8911e7cbd5bec66f50d093f3f45976 | |
| parent | 19cd7537bdae6685c31677a01e08850612ba87f6 (diff) | |
| download | linux-3.10-5b23dbe8173c212d6a326e35347b038705603d39.tar.gz linux-3.10-5b23dbe8173c212d6a326e35347b038705603d39.tar.bz2 linux-3.10-5b23dbe8173c212d6a326e35347b038705603d39.zip | |
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>
| -rw-r--r-- | include/linux/hugetlb.h | 4 | ||||
| -rw-r--r-- | mm/hugetlb.c | 5 | ||||
| -rw-r--r-- | mm/memory.c | 2 |
3 files changed, 6 insertions, 5 deletions
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index ea0f50bfbe0..e22368656b3 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -19,7 +19,7 @@ static inline int is_vm_hugetlb_page(struct vm_area_struct *vma) 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 *); @@ -106,7 +106,7 @@ static inline unsigned long hugetlb_total_pages(void) return 0; } -#define follow_hugetlb_page(m,v,p,vs,a,b,i) ({ BUG(); 0; }) +#define follow_hugetlb_page(m,v,p,vs,a,b,i,w) ({ BUG(); 0; }) #define follow_huge_addr(mm, addr, write) ERR_PTR(-EINVAL) #define copy_hugetlb_page_range(src, dst, vma) ({ BUG(); 0; }) #define hugetlb_prefault(mapping, vma) ({ BUG(); 0; }) 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, 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 9791e478684..7b0403bfc97 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; } |