Re: [PATCH net-next v4 8/9] tap: Keep hdr_len in tap_get_user()

Akihiko Odaki wrote:

hdr_len is repeatedly used so keep it in a local variable.

Signed-off-by: Akihiko Odaki akihiko.odaki@daynix.com

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.