mm: replace get_user_pages_unlocked() write/force parameters with gup_flags

This removes the 'write' and 'force' use from get_user_pages_unlocked()
and replaces them with 'gup_flags' to make the use of FOLL_FORCE
explicit in callers as use of this flag can result in surprising
behaviour (and hence bugs) within the mm subsystem.

Signed-off-by: Lorenzo Stoakes <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Lorenzo Stoakes 2016-10-13 01:20:13 +01:00 • committed by Linus Torvalds
commit c164154f66
14 changed files with 27 additions and 36 deletions

View file

@ -907,17 +907,10 @@ EXPORT_SYMBOL(__get_user_pages_unlocked);
* "force" parameter).
*/
long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
int write, int force, struct page **pages)
struct page **pages, unsigned int gup_flags)
{
unsigned int flags = FOLL_TOUCH;
if (write)
flags |= FOLL_WRITE;
if (force)
flags |= FOLL_FORCE;
return __get_user_pages_unlocked(current, current->mm, start, nr_pages,
pages, flags);
pages, gup_flags | FOLL_TOUCH);
}
EXPORT_SYMBOL(get_user_pages_unlocked);
@ -1535,7 +1528,8 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
start += nr << PAGE_SHIFT;
pages += nr;
ret = get_user_pages_unlocked(start, nr_pages - nr, write, 0, pages);
ret = get_user_pages_unlocked(start, nr_pages - nr, pages,
write ? FOLL_WRITE : 0);
/* Have to be a bit careful with return values */
if (nr > 0) {

View file

@ -197,17 +197,10 @@ long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,
EXPORT_SYMBOL(__get_user_pages_unlocked);
long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
int write, int force, struct page **pages)
struct page **pages, unsigned int gup_flags)
{
unsigned int flags = 0;
if (write)
flags |= FOLL_WRITE;
if (force)
flags |= FOLL_FORCE;
return __get_user_pages_unlocked(current, current->mm, start, nr_pages,
pages, flags);
pages, gup_flags);
}
EXPORT_SYMBOL(get_user_pages_unlocked);

View file

@ -283,7 +283,8 @@ EXPORT_SYMBOL_GPL(__get_user_pages_fast);
int __weak get_user_pages_fast(unsigned long start,
int nr_pages, int write, struct page **pages)
{
return get_user_pages_unlocked(start, nr_pages, write, 0, pages);
return get_user_pages_unlocked(start, nr_pages, pages,
write ? FOLL_WRITE : 0);
}
EXPORT_SYMBOL_GPL(get_user_pages_fast);