Re: [PATCH net-next v5 6/7] 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

@@ -682,11 +683,8 @@ 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;
  

I forgot earlier: this can also use single line statement

copylen = max(copylen, ETH_HLEN);

And perhaps easiest to follow is

copylen = hdr_len ?: GOODCOPY_LEN; copylen = min(copylen, good_linear); copylen = max(copylen, ETH_HLEN);

linear = copylen;
i = *from;

@@ -697,11 +695,9 @@ 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;
  

Same