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authorLorenzo Stoakes <lstoakes@gmail.com>2016-10-13 01:20:11 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2016-10-18 14:13:36 -0700
commit859110d7497cdd0e6b21010d6f777049d676382c (patch)
treed2da6062b292dd6478a607bb8d564047d087144c /mm
parent19be0eaffa3ac7d8eb6784ad9bdbc7d67ed8e619 (diff)
mm: remove write/force parameters from __get_user_pages_locked()
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>
Diffstat (limited to 'mm')
-rw-r--r--mm/gup.c47
1 files changed, 33 insertions, 14 deletions
diff --git a/mm/gup.c b/mm/gup.c
index 22cc22e7432f..720eb9385204 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -739,7 +739,6 @@ 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,
@@ -757,10 +756,6 @@ 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;
@@ -856,9 +851,15 @@ long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
int write, int force, struct page **pages,
int *locked)
{
+ unsigned int flags = FOLL_TOUCH;
+
+ if (write)
+ flags |= FOLL_WRITE;
+ if (force)
+ flags |= FOLL_FORCE;
+
return __get_user_pages_locked(current, current->mm, start, nr_pages,
- write, force, pages, NULL, locked, true,
- FOLL_TOUCH);
+ pages, NULL, locked, true, flags);
}
EXPORT_SYMBOL(get_user_pages_locked);
@@ -879,9 +880,15 @@ __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;
@@ -973,9 +980,15 @@ long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm,
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 | FOLL_REMOTE);
+ unsigned int flags = FOLL_TOUCH | FOLL_REMOTE;
+
+ 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_remote);
@@ -989,9 +1002,15 @@ long get_user_pages(unsigned long start, unsigned long nr_pages,
int write, int force, struct page **pages,
struct vm_area_struct **vmas)
{
+ unsigned int flags = FOLL_TOUCH;
+
+ if (write)
+ flags |= FOLL_WRITE;
+ if (force)
+ flags |= FOLL_FORCE;
+
return __get_user_pages_locked(current, current->mm, start, nr_pages,
- write, force, pages, vmas, NULL, false,
- FOLL_TOUCH);
+ pages, vmas, NULL, false, flags);
}
EXPORT_SYMBOL(get_user_pages);