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authorLorenzo Stoakes <lstoakes@gmail.com>2016-10-13 01:20:14 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2016-10-19 08:11:05 -0700
commit3b913179c3fa89dd0e304193fa0c746fc0481447 (patch)
tree9d19f80b42aa94ccdd93d926332aee9881ac439b
parentc164154f66f0c9b02673f07aa4f044f1d9c70274 (diff)
mm: replace get_user_pages_locked() write/force parameters with gup_flags
This removes the 'write' and 'force' use from get_user_pages_locked() 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 <lstoakes@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/mm.h2
-rw-r--r--mm/frame_vector.c8
-rw-r--r--mm/gup.c12
-rw-r--r--mm/nommu.c5
4 files changed, 15 insertions, 12 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h
index abd53f2eb74e..9fe9b0438169 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1282,7 +1282,7 @@ long get_user_pages(unsigned long start, unsigned long nr_pages,
int write, int force, struct page **pages,
struct vm_area_struct **vmas);
long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
- int write, int force, struct page **pages, int *locked);
+ unsigned int gup_flags, struct page **pages, int *locked);
long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,
unsigned long start, unsigned long nr_pages,
struct page **pages, unsigned int gup_flags);
diff --git a/mm/frame_vector.c b/mm/frame_vector.c
index 381bb07ed14f..81b67498bb9c 100644
--- a/mm/frame_vector.c
+++ b/mm/frame_vector.c
@@ -41,10 +41,16 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
int ret = 0;
int err;
int locked;
+ unsigned int gup_flags = 0;
if (nr_frames == 0)
return 0;
+ if (write)
+ gup_flags |= FOLL_WRITE;
+ if (force)
+ gup_flags |= FOLL_FORCE;
+
if (WARN_ON_ONCE(nr_frames > vec->nr_allocated))
nr_frames = vec->nr_allocated;
@@ -59,7 +65,7 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
vec->got_ref = true;
vec->is_pfns = false;
ret = get_user_pages_locked(start, nr_frames,
- write, force, (struct page **)(vec->ptrs), &locked);
+ gup_flags, (struct page **)(vec->ptrs), &locked);
goto out;
}
diff --git a/mm/gup.c b/mm/gup.c
index 373d1ec006e4..3cfb55ef0cf4 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -848,18 +848,12 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk,
* up_read(&mm->mmap_sem);
*/
long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
- int write, int force, struct page **pages,
+ unsigned int gup_flags, 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,
- pages, NULL, locked, true, flags);
+ pages, NULL, locked, true,
+ gup_flags | FOLL_TOUCH);
}
EXPORT_SYMBOL(get_user_pages_locked);
diff --git a/mm/nommu.c b/mm/nommu.c
index 7e27add39f7e..842cfdd1a31e 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -176,9 +176,12 @@ long get_user_pages(unsigned long start, unsigned long nr_pages,
EXPORT_SYMBOL(get_user_pages);
long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
- int write, int force, struct page **pages,
+ unsigned int gup_flags, struct page **pages,
int *locked)
{
+ int write = gup_flags & FOLL_WRITE;
+ int force = gup_flags & FOLL_FORCE;
+
return get_user_pages(start, nr_pages, write, force, pages, NULL);
}
EXPORT_SYMBOL(get_user_pages_locked);