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tap: Keep hdr_len in tap_get_user()

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

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250207-tun-v6-6-fb49cf8b103e@daynix.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Akihiko Odaki 2025-02-07 15:10:56 +09:00 committed by Jakub Kicinski
parent 1d41e2fa93
commit 74212f20f3
1 changed files with 10 additions and 18 deletions
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28
drivers/net/tap.c
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@ -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;
@ -663,13 +664,13 @@ static ssize_t tap_get_user(struct tap_queue *q, void *msg_control,
if (!copy_from_iter_full(&vnet_hdr, sizeof(vnet_hdr), from))
goto err;
iov_iter_advance(from, vnet_hdr_len - sizeof(vnet_hdr));
if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
tap16_to_cpu(q, vnet_hdr.csum_start) +
tap16_to_cpu(q, vnet_hdr.csum_offset) + 2 >
tap16_to_cpu(q, vnet_hdr.hdr_len))
vnet_hdr.hdr_len = cpu_to_tap16(q,
tap16_to_cpu(q, vnet_hdr.csum_start) +
tap16_to_cpu(q, vnet_hdr.csum_offset) + 2);
hdr_len = tap16_to_cpu(q, vnet_hdr.hdr_len);
if (vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
hdr_len = max(tap16_to_cpu(q, vnet_hdr.csum_start) +
tap16_to_cpu(q, vnet_hdr.csum_offset) + 2,
hdr_len);
vnet_hdr.hdr_len = cpu_to_tap16(q, hdr_len);
}
err = -EINVAL;
if (tap16_to_cpu(q, vnet_hdr.hdr_len) > len)
goto err;
@ -682,12 +683,7 @@ 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 = ETH_HLEN;
copylen = clamp(hdr_len ?: GOODCOPY_LEN, ETH_HLEN, good_linear);
linear = copylen;
i = *from;
iov_iter_advance(&i, copylen);
@ -697,11 +693,7 @@ 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 = clamp(hdr_len, ETH_HLEN, good_linear);
}
skb = tap_alloc_skb(&q->sk, TAP_RESERVE, copylen,