xenfs/xenbus: report partial reads/writes correctly
copy_(to|from)_user return the number of uncopied bytes, so a successful
return is 0, and any non-zero result indicates some degree of failure.
Reported-by: "Jun Zhu (Intern)" <Jun.Zhu@citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
diff --git a/drivers/xen/xenfs/xenbus.c b/drivers/xen/xenfs/xenbus.c
index 9d5b519..d2a9058 100644
--- a/drivers/xen/xenfs/xenbus.c
+++ b/drivers/xen/xenfs/xenbus.c
@@ -142,7 +142,7 @@
i += sz - ret;
rb->cons += sz - ret;
- if (ret != sz) {
+ if (ret != 0) {
if (i == 0)
i = -EFAULT;
goto out;
@@ -453,7 +453,7 @@
ret = copy_from_user(u->u.buffer + u->len, ubuf, len);
- if (ret == len) {
+ if (ret != 0) {
rc = -EFAULT;
goto out;
}