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author | Nick Piggin <nickpiggin@yahoo.com.au> | 2005-08-03 20:24:01 +1000 |
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committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-08-03 09:12:05 -0700 |
commit | f33ea7f404e592e4563b12101b7a4d17da6558d7 (patch) | |
tree | 1d587ad8a06cb6d2e3a187f0312c8a524ffefe53 /include/linux | |
parent | 5cb4cc0d8211c490537c8568001958fc76741312 (diff) | |
download | op-kernel-dev-f33ea7f404e592e4563b12101b7a4d17da6558d7.zip op-kernel-dev-f33ea7f404e592e4563b12101b7a4d17da6558d7.tar.gz |
[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.h | 22 |
1 files changed, 17 insertions, 5 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 6eb7f48..82d7024 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -625,10 +625,16 @@ static inline int page_mapped(struct page *page) * Used to decide whether a process gets delivered SIGBUS or * just gets major/minor fault counters bumped up. */ -#define VM_FAULT_OOM (-1) -#define VM_FAULT_SIGBUS 0 -#define VM_FAULT_MINOR 1 -#define VM_FAULT_MAJOR 2 +#define VM_FAULT_OOM 0x00 +#define VM_FAULT_SIGBUS 0x01 +#define VM_FAULT_MINOR 0x02 +#define VM_FAULT_MAJOR 0x03 + +/* + * Special case for get_user_pages. + * Must be in a distinct bit from the above VM_FAULT_ flags. + */ +#define VM_FAULT_WRITE 0x10 #define offset_in_page(p) ((unsigned long)(p) & ~PAGE_MASK) @@ -704,7 +710,13 @@ extern pte_t *FASTCALL(pte_alloc_kernel(struct mm_struct *mm, pmd_t *pmd, unsign extern pte_t *FASTCALL(pte_alloc_map(struct mm_struct *mm, pmd_t *pmd, unsigned long address)); extern int install_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, struct page *page, pgprot_t prot); extern int install_file_pte(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, unsigned long pgoff, pgprot_t prot); -extern int handle_mm_fault(struct mm_struct *mm,struct vm_area_struct *vma, unsigned long address, int write_access); +extern int __handle_mm_fault(struct mm_struct *mm,struct vm_area_struct *vma, unsigned long address, int write_access); + +static inline int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, int write_access) +{ + return __handle_mm_fault(mm, vma, address, write_access) & (~VM_FAULT_WRITE); +} + extern int make_pages_present(unsigned long addr, unsigned long end); extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write); void install_arg_page(struct vm_area_struct *, struct page *, unsigned long); |