6.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Stefano Garzarella <sgarzare@xxxxxxxxxx>
commit 7aed44babc7f97e82b38e9a68515e699692cc100 upstream.
In the while loop of vringh_iov_xfer(), `partlen` could be 0 if one of
the `iov` has 0 lenght.
In this case, we should skip the iov and go to the next one.
But calling vringh_kiov_advance() with 0 lenght does not cause the
advancement, since it returns immediately if asked to advance by 0 bytes.
Let's restore the code that was there before commit b8c06ad4d67d
("vringh: implement vringh_kiov_advance()"), avoiding using
vringh_kiov_advance().
Fixes: b8c06ad4d67d ("vringh: implement vringh_kiov_advance()")
Cc: stable@xxxxxxxxxxxxxxx
Reported-by: Jason Wang <jasowang@xxxxxxxxxx>
Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>
Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/vhost/vringh.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
--- a/drivers/vhost/vringh.c
+++ b/drivers/vhost/vringh.c
@@ -123,8 +123,18 @@ static inline ssize_t vringh_iov_xfer(st
done += partlen;
len -= partlen;
ptr += partlen;
+ iov->consumed += partlen;
+ iov->iov[iov->i].iov_len -= partlen;
+ iov->iov[iov->i].iov_base += partlen;
- vringh_kiov_advance(iov, partlen);
+ if (!iov->iov[iov->i].iov_len) {
+ /* Fix up old iov element then increment. */
+ iov->iov[iov->i].iov_len = iov->consumed;
+ iov->iov[iov->i].iov_base -= iov->consumed;
+
+ iov->consumed = 0;
+ iov->i++;
+ }
}
return done;
}
