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Commit ffe6376c authored by Lorenzo Stoakes's avatar Lorenzo Stoakes Committed by Greg Kroah-Hartman
Browse files

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



commit 3b913179c3fa89dd0e304193fa0c746fc0481447 upstream.

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: default avatarLorenzo Stoakes <lstoakes@gmail.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 4.4: adjust context]
Signed-off-by: default avatarBen Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 2b29980e

include/linux/mm.h

+1 −2
Original line number Diff line number Diff line
@@ -1203,8 +1203,7 @@ long get_user_pages(struct task_struct *tsk, struct mm_struct *mm, 
		    struct vm_area_struct **vmas);

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,

		    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);

mm/frame_vector.c

+7 −1
Original line number Diff line number Diff line
@@ -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(current, mm, start, nr_frames,

			write, force, (struct page **)(vec->ptrs), &locked);

			gup_flags, (struct page **)(vec->ptrs), &locked);

		goto out;

	}

mm/gup.c

+3 −9
Original line number Diff line number Diff line
@@ -737,18 +737,12 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk, 
 */

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,

			   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(tsk, mm, start, nr_pages,

				       pages, NULL, locked, true, flags);

				       pages, NULL, locked, true,

				       gup_flags | FOLL_TOUCH);

}

EXPORT_SYMBOL(get_user_pages_locked);

mm/nommu.c

+4 −1
Original line number Diff line number Diff line
@@ -201,9 +201,12 @@ EXPORT_SYMBOL(get_user_pages); 


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,

			   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(tsk, mm, start, nr_pages, write, force,

			      pages, NULL);

}