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Fix up recent get_user_pages() handling 

The VM_FAULT_WRITE thing is an extra bit, not a valid return value, and
has to be treated as such by get_user_pages().

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
hifive-unleashed-5.1
Linus Torvalds 2005-08-03 10:07:09 -07:00
parent f33ea7f404
commit a68d2ebc15
1 changed files with 13 additions and 9 deletions
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22
mm/memory.c
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@ -949,6 +949,8 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
cond_resched_lock(&mm->page_table_lock);
while (!(page = follow_page(mm, start, write_access))) {
int ret;
/*
* Shortcut for anonymous pages. We don't want
* to force the creation of pages tables for
@ -961,16 +963,18 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
break;
}
spin_unlock(&mm->page_table_lock);
switch (__handle_mm_fault(mm, vma, start,
write_access)) {
case VM_FAULT_WRITE:
/*
* do_wp_page has broken COW when
* necessary, even if maybe_mkwrite
* decided not to set pte_write
*/
ret = __handle_mm_fault(mm, vma, start, write_access);
/*
* The VM_FAULT_WRITE bit tells us that do_wp_page has
* broken COW when necessary, even if maybe_mkwrite
* decided not to set pte_write. We can thus safely do
* subsequent page lookups as if they were reads.
*/
if (ret & VM_FAULT_WRITE)
write_access = 0;
/* FALLTHRU */
switch (ret & ~VM_FAULT_WRITE) {
case VM_FAULT_MINOR:
tsk->min_flt++;
break;