From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Hubbard Subject: [PATCH v2 08/18] mm/process_vm_access: set FOLL_PIN via pin_user_pages_remote() Date: Sun, 3 Nov 2019 13:18:03 -0800 Message-ID: <20191103211813.213227-9-jhubbard@nvidia.com> References: <20191103211813.213227-1-jhubbard@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20191103211813.213227-1-jhubbard@nvidia.com> Sender: netdev-owner@vger.kernel.org To: Andrew Morton Cc: Al Viro , Alex Williamson , Benjamin Herrenschmidt , =?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= , Christoph Hellwig , Dan Williams , Daniel Vetter , Dave Chinner , David Airlie , "David S . Miller" , Ira Weiny , Jan Kara , Jason Gunthorpe , Jens Axboe , Jonathan Corbet , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , Magnus Karlsson , Mauro Carvalho Chehab , Michael Ellerman List-Id: dri-devel@lists.freedesktop.org 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(). Reviewed-by: Ira Weiny Signed-off-by: John Hubbard --- mm/process_vm_access.c | 28 +++++++++++++++------------- 1 file changed, 15 insertions(+), 13 deletions(-) diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c index 357aa7bef6c0..fd20ab675b85 100644 --- a/mm/process_vm_access.c +++ b/mm/process_vm_access.c @@ -42,12 +42,11 @@ static int process_vm_rw_pages(struct page **pages, if (copy > len) copy =3D len; =20 - if (vm_write) { + if (vm_write) copied =3D copy_page_from_iter(page, offset, copy, iter); - set_page_dirty_lock(page); - } else { + else copied =3D copy_page_to_iter(page, offset, copy, iter); - } + len -=3D 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 |=3D FOLL_WRITE; =20 while (!rc && nr_pages && iov_iter_count(iter)) { - int pages =3D min(nr_pages, max_pages_per_loop); + int pinned_pages =3D min(nr_pages, max_pages_per_loop); int locked =3D 1; size_t bytes; =20 @@ -106,14 +105,15 @@ static int process_vm_rw_single_vec(unsigned long add= r, * current/current->mm */ down_read(&mm->mmap_sem); - pages =3D get_user_pages_remote(task, mm, pa, pages, flags, - process_pages, NULL, &locked); + pinned_pages =3D pin_user_pages_remote(task, mm, pa, pinned_pages, + flags, process_pages, + NULL, &locked); if (locked) up_read(&mm->mmap_sem); - if (pages <=3D 0) + if (pinned_pages <=3D 0) return -EFAULT; =20 - bytes =3D pages * PAGE_SIZE - start_offset; + bytes =3D pinned_pages * PAGE_SIZE - start_offset; if (bytes > len) bytes =3D len; =20 @@ -122,10 +122,12 @@ static int process_vm_rw_single_vec(unsigned long add= r, vm_write); len -=3D bytes; start_offset =3D 0; - nr_pages -=3D pages; - pa +=3D pages * PAGE_SIZE; - while (pages) - put_page(process_pages[--pages]); + nr_pages -=3D pinned_pages; + pa +=3D 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); } =20 return rc; --=20 2.23.0