[PATCH net v3 8/9] tap: Keep hdr_len in tap_get_user()
From: Akihiko Odaki <hidden>
Date: 2025-01-16 08:09:33
Also in:
kvm, linux-doc, linux-kselftest, lkml, virtualization
Subsystem:
networking drivers, the rest, tun/tap driver · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Willem de Bruijn, Jason Wang
hdr_len is repeatedly used so keep it in a local variable. Signed-off-by: Akihiko Odaki <redacted> --- 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 061c2f27dfc8..7ee2e9ee2a89 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; } skb = tap_alloc_skb(&q->sk, TAP_RESERVE, copylen,
--
2.47.1