tap_get_user() used to track the length of iov_iter with another variable. We can use iov_iter_count() to determine the current length to avoid such chores.
Signed-off-by: Akihiko Odaki akihiko.odaki@daynix.com --- drivers/net/tap.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/net/tap.c b/drivers/net/tap.c index 5aa41d5f7765..061c2f27dfc8 100644 --- a/drivers/net/tap.c +++ b/drivers/net/tap.c @@ -641,7 +641,7 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control, struct sk_buff *skb; struct tap_dev *tap; unsigned long total_len = iov_iter_count(from); - unsigned long len = total_len; + unsigned long len; int err; struct virtio_net_hdr vnet_hdr = { 0 }; int vnet_hdr_len = 0; @@ -655,9 +655,8 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control, vnet_hdr_len = READ_ONCE(q->vnet_hdr_sz);
err = -EINVAL; - if (len < vnet_hdr_len) + if (iov_iter_count(from) < vnet_hdr_len) goto err; - len -= vnet_hdr_len;
err = -EFAULT; if (!copy_from_iter_full(&vnet_hdr, sizeof(vnet_hdr), from)) @@ -671,10 +670,12 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control, tap16_to_cpu(q, vnet_hdr.csum_start) + tap16_to_cpu(q, vnet_hdr.csum_offset) + 2); err = -EINVAL; - if (tap16_to_cpu(q, vnet_hdr.hdr_len) > len) + if (tap16_to_cpu(q, vnet_hdr.hdr_len) > iov_iter_count(from)) goto err; }
+ len = iov_iter_count(from); + err = -EINVAL; if (unlikely(len < ETH_HLEN)) goto err;