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authorNick Piggin <nickpiggin@yahoo.com.au>2005-08-03 06:24:01 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2005-08-03 12:12:05 -0400
commitf33ea7f404e592e4563b12101b7a4d17da6558d7 (patch)
tree1d587ad8a06cb6d2e3a187f0312c8a524ffefe53 /include/linux
parent5cb4cc0d8211c490537c8568001958fc76741312 (diff)
[PATCH] fix get_user_pages bug
Checking pte_dirty instead of pte_write in __follow_page is problematic for s390, and for copy_one_pte which leaves dirty when clearing write. So revert __follow_page to check pte_write as before, and make do_wp_page pass back a special extra VM_FAULT_WRITE bit to say it has done its full job: once get_user_pages receives this value, it no longer requires pte_write in __follow_page. But most callers of handle_mm_fault, in the various architectures, have switch statements which do not expect this new case. To avoid changing them all in a hurry, make an inline wrapper function (using the old name) that masks off the new bit, and use the extended interface with double underscores. Yes, we do have a call to do_wp_page from do_swap_page, but no need to change that: in rare case it's needed, another do_wp_page will follow. Signed-off-by: Hugh Dickins <hugh@veritas.com> [ Cleanups by Nick Piggin ] Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/mm.h22
1 files changed, 17 insertions, 5 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 6eb7f48317f8..82d7024f0765 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -625,10 +625,16 @@ static inline int page_mapped(struct page *page)
625 * Used to decide whether a process gets delivered SIGBUS or 625 * Used to decide whether a process gets delivered SIGBUS or
626 * just gets major/minor fault counters bumped up. 626 * just gets major/minor fault counters bumped up.
627 */ 627 */
628#define VM_FAULT_OOM (-1) 628#define VM_FAULT_OOM 0x00
629#define VM_FAULT_SIGBUS 0 629#define VM_FAULT_SIGBUS 0x01
630#define VM_FAULT_MINOR 1 630#define VM_FAULT_MINOR 0x02
631#define VM_FAULT_MAJOR 2 631#define VM_FAULT_MAJOR 0x03
632
633/*
634 * Special case for get_user_pages.
635 * Must be in a distinct bit from the above VM_FAULT_ flags.
636 */
637#define VM_FAULT_WRITE 0x10
632 638
633#define offset_in_page(p) ((unsigned long)(p) & ~PAGE_MASK) 639#define offset_in_page(p) ((unsigned long)(p) & ~PAGE_MASK)
634 640
@@ -704,7 +710,13 @@ extern pte_t *FASTCALL(pte_alloc_kernel(struct mm_struct *mm, pmd_t *pmd, unsign
704extern pte_t *FASTCALL(pte_alloc_map(struct mm_struct *mm, pmd_t *pmd, unsigned long address)); 710extern pte_t *FASTCALL(pte_alloc_map(struct mm_struct *mm, pmd_t *pmd, unsigned long address));
705extern int install_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, struct page *page, pgprot_t prot); 711extern int install_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, struct page *page, pgprot_t prot);
706extern int install_file_pte(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, unsigned long pgoff, pgprot_t prot); 712extern int install_file_pte(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, unsigned long pgoff, pgprot_t prot);
707extern int handle_mm_fault(struct mm_struct *mm,struct vm_area_struct *vma, unsigned long address, int write_access); 713extern int __handle_mm_fault(struct mm_struct *mm,struct vm_area_struct *vma, unsigned long address, int write_access);
714
715static inline int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, int write_access)
716{
717 return __handle_mm_fault(mm, vma, address, write_access) & (~VM_FAULT_WRITE);
718}
719
708extern int make_pages_present(unsigned long addr, unsigned long end); 720extern int make_pages_present(unsigned long addr, unsigned long end);
709extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write); 721extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write);
710void install_arg_page(struct vm_area_struct *, struct page *, unsigned long); 722void install_arg_page(struct vm_area_struct *, struct page *, unsigned long);