Commit 803e4572 authored by John Hubbard's avatar John Hubbard Committed by Linus Torvalds
Browse files

mm/process_vm_access: set FOLL_PIN via pin_user_pages_remote() 

Convert process_vm_access to use the new pin_user_pages_remote() call,
which sets FOLL_PIN.  Setting FOLL_PIN is now required for code that
requires tracking of pinned pages.

Also, release the pages via put_user_page*().

Also, rename "pages" to "pinned_pages", as this makes for easier reading
of process_vm_rw_single_vec().

Link: http://lkml.kernel.org/r/20200107224558.2362728-15-jhubbard@nvidia.com


Signed-off-by: default avatarJohn Hubbard <jhubbard@nvidia.com>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Reviewed-by: default avatarJérôme Glisse <jglisse@redhat.com>
Reviewed-by: default avatarIra Weiny <ira.weiny@intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Björn Töpel <bjorn.topel@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Leon Romanovsky <leonro@mellanox.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent dfa0a4ff

mm/process_vm_access.c

+15 −13
Original line number Diff line number Diff line
@@ -42,12 +42,11 @@ static int process_vm_rw_pages(struct page **pages, 
		if (copy > len)

			copy = len;



		if (vm_write) {

		if (vm_write)

			copied = copy_page_from_iter(page, offset, copy, iter);

			set_page_dirty_lock(page);

		} else {

		else

			copied = copy_page_to_iter(page, offset, copy, iter);

		}



		len -= copied;

		if (copied < copy && iov_iter_count(iter))

			return -EFAULT;
@@ -96,7 +95,7 @@ static int process_vm_rw_single_vec(unsigned long addr, 
		flags |= FOLL_WRITE;



	while (!rc && nr_pages && iov_iter_count(iter)) {

		int pages = min(nr_pages, max_pages_per_loop);

		int pinned_pages = min(nr_pages, max_pages_per_loop);

		int locked = 1;

		size_t bytes;
@@ -106,14 +105,15 @@ static int process_vm_rw_single_vec(unsigned long addr, 
		 * current/current->mm

		 */

		down_read(&mm->mmap_sem);

		pages = get_user_pages_remote(task, mm, pa, pages, flags,

					      process_pages, NULL, &locked);

		pinned_pages = pin_user_pages_remote(task, mm, pa, pinned_pages,

						     flags, process_pages,

						     NULL, &locked);

		if (locked)

			up_read(&mm->mmap_sem);

		if (pages <= 0)

		if (pinned_pages <= 0)

			return -EFAULT;



		bytes = pages * PAGE_SIZE - start_offset;

		bytes = pinned_pages * PAGE_SIZE - start_offset;

		if (bytes > len)

			bytes = len;
@@ -122,10 +122,12 @@ static int process_vm_rw_single_vec(unsigned long addr, 
					 vm_write);

		len -= bytes;

		start_offset = 0;

		nr_pages -= pages;

		pa += pages * PAGE_SIZE;

		while (pages)

			put_page(process_pages[--pages]);

		nr_pages -= pinned_pages;

		pa += pinned_pages * PAGE_SIZE;



		/* If vm_write is set, the pages need to be made dirty: */

		put_user_pages_dirty_lock(process_pages, pinned_pages,

					  vm_write);

	}



	return rc;