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Commit 859110d7 authored by Lorenzo Stoakes's avatar Lorenzo Stoakes Committed by Linus Torvalds
Browse files

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: default avatarLorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 19be0eaf

mm/gup.c

+33 −14
Original line number Diff line number Diff line
@@ -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);