Akihiko Odaki wrote:
> hdr_len is repeatedly used so keep it in a local variable.
>
> Signed-off-by: Akihiko Odaki <akihiko.odaki@xxxxxxxxxx>
> ---
> drivers/net/tap.c | 17 +++++++----------
> 1 file changed, 7 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/net/tap.c b/drivers/net/tap.c
> index 061c2f27dfc83f5e6d0bea4da0e845cc429b1fd8..7ee2e9ee2a89fd539b087496b92d2f6198266f44 100644
> --- a/drivers/net/tap.c
> +++ b/drivers/net/tap.c
> @@ -645,6 +645,7 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control,
> int err;
> struct virtio_net_hdr vnet_hdr = { 0 };
> int vnet_hdr_len = 0;
> + int hdr_len = 0;
> int copylen = 0;
> int depth;
> bool zerocopy = false;
> @@ -672,6 +673,7 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control,
> err = -EINVAL;
> if (tap16_to_cpu(q, vnet_hdr.hdr_len) > iov_iter_count(from))
> goto err;
> + hdr_len = tap16_to_cpu(q, vnet_hdr.hdr_len);
> }
>
> len = iov_iter_count(from);
> @@ -683,11 +685,8 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control,
> if (msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY)) {
> struct iov_iter i;
>
> - copylen = vnet_hdr.hdr_len ?
> - tap16_to_cpu(q, vnet_hdr.hdr_len) : GOODCOPY_LEN;
> - if (copylen > good_linear)
> - copylen = good_linear;
> - else if (copylen < ETH_HLEN)
> + copylen = min(hdr_len ? hdr_len : GOODCOPY_LEN, good_linear);
> + if (copylen < ETH_HLEN)
> copylen = ETH_HLEN;
> linear = copylen;
> i = *from;
> @@ -698,11 +697,9 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control,
>
> if (!zerocopy) {
> copylen = len;
> - linear = tap16_to_cpu(q, vnet_hdr.hdr_len);
> - if (linear > good_linear)
> - linear = good_linear;
> - else if (linear < ETH_HLEN)
> - linear = ETH_HLEN;
> + linear = min(hdr_len, good_linear);
> + if (copylen < ETH_HLEN)
> + copylen = ETH_HLEN;
Similar to previous patch, I don't think this patch is significant
enough to warrant the code churn.
