From 53f131c284e83c29c227c0938926a82b2ed4d7ba Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Tue, 23 Feb 2021 17:26:21 +0100 Subject: [PATCH] xen-front-pgdir-shbuf: don't record wrong grant handle upon error In order for subsequent unmapping to not mistakenly unmap handle 0, record a perceived always-invalid one instead. Signed-off-by: Jan Beulich Reviewed-by: Juergen Gross Reviewed-by: Oleksandr Andrushchenko Link: https://lore.kernel.org/r/82414b0f-1b63-5509-7c1d-5bcc8239a3de@suse.com Signed-off-by: Boris Ostrovsky --- drivers/xen/xen-front-pgdir-shbuf.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/xen/xen-front-pgdir-shbuf.c b/drivers/xen/xen-front-pgdir-shbuf.c index 48a658dc7ccf..81b6e13fa5ec 100644 --- a/drivers/xen/xen-front-pgdir-shbuf.c +++ b/drivers/xen/xen-front-pgdir-shbuf.c @@ -305,11 +305,18 @@ static int backend_map(struct xen_front_pgdir_shbuf *buf) /* Save handles even if error, so we can unmap. */ for (cur_page = 0; cur_page < buf->num_pages; cur_page++) { - buf->backend_map_handles[cur_page] = map_ops[cur_page].handle; - if (unlikely(map_ops[cur_page].status != GNTST_okay)) + if (likely(map_ops[cur_page].status == GNTST_okay)) { + buf->backend_map_handles[cur_page] = + map_ops[cur_page].handle; + } else { + buf->backend_map_handles[cur_page] = + INVALID_GRANT_HANDLE; + if (!ret) + ret = -ENXIO; dev_err(&buf->xb_dev->dev, "Failed to map page %d: %d\n", cur_page, map_ops[cur_page].status); + } } if (ret) {