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>
This commit is contained in:
Jeremy Fitzhardinge 2010-08-25 12:19:53 -07:00
parent 6280f190da
commit fb27cfbcbd

View File

@ -142,7 +142,7 @@ static ssize_t xenbus_file_read(struct file *filp,
i += sz - ret;
rb->cons += sz - ret;
if (ret != sz) {
if (ret != 0) {
if (i == 0)
i = -EFAULT;
goto out;
@ -453,7 +453,7 @@ static ssize_t xenbus_file_write(struct file *filp,
ret = copy_from_user(u->u.buffer + u->len, ubuf, len);
if (ret == len) {
if (ret != 0) {
rc = -EFAULT;
goto out;
}