diff options
author | Lorenzo Stoakes <lstoakes@gmail.com> | 2016-10-13 01:20:11 +0100 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-12-17 21:55:16 +0100 |
commit | 6a3c9524df93e9597d30c2d32114950772fce58e (patch) | |
tree | 2f6d15a2239a5ed3f06a1b638cc951ef6b831d53 /mm | |
parent | 8aca77150a9a2f89aba94f62a09c95f9a00c2956 (diff) |
mm: remove write/force parameters from __get_user_pages_locked()
commit 859110d7497cdd0e6b21010d6f777049d676382c upstream.
This removes the redundant 'write' and 'force' parameters from
__get_user_pages_locked() 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 <lstoakes@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 4.4:
- Drop change in get_user_pages_remote()
- Adjust context]
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/gup.c | 37 |
1 files changed, 26 insertions, 11 deletions
@@ -627,7 +627,6 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, unsigned long nr_pages, - int write, int force, struct page **pages, struct vm_area_struct **vmas, int *locked, bool notify_drop, @@ -645,10 +644,6 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk, if (pages) flags |= FOLL_GET; - if (write) - flags |= FOLL_WRITE; - if (force) - flags |= FOLL_FORCE; pages_done = 0; lock_dropped = false; @@ -745,8 +740,15 @@ long get_user_pages_locked(struct task_struct *tsk, struct mm_struct *mm, int write, int force, struct page **pages, int *locked) { - return __get_user_pages_locked(tsk, mm, start, nr_pages, write, force, - pages, NULL, locked, true, FOLL_TOUCH); + unsigned int flags = FOLL_TOUCH; + + if (write) + flags |= FOLL_WRITE; + if (force) + flags |= FOLL_FORCE; + + return __get_user_pages_locked(tsk, mm, start, nr_pages, + pages, NULL, locked, true, flags); } EXPORT_SYMBOL(get_user_pages_locked); @@ -767,9 +769,15 @@ __always_inline long __get_user_pages_unlocked(struct task_struct *tsk, struct m { long ret; int locked = 1; + + if (write) + gup_flags |= FOLL_WRITE; + if (force) + gup_flags |= FOLL_FORCE; + down_read(&mm->mmap_sem); - ret = __get_user_pages_locked(tsk, mm, start, nr_pages, write, force, - pages, NULL, &locked, false, gup_flags); + ret = __get_user_pages_locked(tsk, mm, start, nr_pages, pages, NULL, + &locked, false, gup_flags); if (locked) up_read(&mm->mmap_sem); return ret; @@ -861,8 +869,15 @@ long get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, unsigned long nr_pages, int write, int force, struct page **pages, struct vm_area_struct **vmas) { - return __get_user_pages_locked(tsk, mm, start, nr_pages, write, force, - pages, vmas, NULL, false, FOLL_TOUCH); + unsigned int flags = FOLL_TOUCH; + + if (write) + flags |= FOLL_WRITE; + if (force) + flags |= FOLL_FORCE; + + return __get_user_pages_locked(tsk, mm, start, nr_pages, + pages, vmas, NULL, false, flags); } EXPORT_SYMBOL(get_user_pages); |