[PATCH net v3 3/9] tun: Keep hdr_len in tun_get_user()
From: Akihiko Odaki <hidden>
Date: 2025-01-16 08:08:55
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/tun.c | 14 +++++--------- 1 file changed, 5 insertions(+), 9 deletions(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index bd272b4736fb..ec56ac865848 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c@@ -1746,6 +1746,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, struct virtio_net_hdr gso = { 0 }; int good_linear; int copylen; + int hdr_len = 0; bool zerocopy = false; int err; u32 rxhash = 0;
@@ -1776,6 +1777,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, if (tun16_to_cpu(tun, gso.hdr_len) > iov_iter_count(from)) return -EINVAL; + hdr_len = tun16_to_cpu(tun, gso.hdr_len); iov_iter_advance(from, vnet_hdr_sz - sizeof(gso)); }
@@ -1783,8 +1785,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, if ((tun->flags & TUN_TYPE_MASK) == IFF_TAP) { align += NET_IP_ALIGN; - if (unlikely(len < ETH_HLEN || - (gso.hdr_len && tun16_to_cpu(tun, gso.hdr_len) < ETH_HLEN))) + if (unlikely(len < ETH_HLEN || (hdr_len && hdr_len < ETH_HLEN))) return -EINVAL; }
@@ -1797,9 +1798,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, * enough room for skb expand head in case it is used. * The rest of the buffer is mapped from userspace. */ - copylen = gso.hdr_len ? tun16_to_cpu(tun, gso.hdr_len) : GOODCOPY_LEN; - if (copylen > good_linear) - copylen = good_linear; + copylen = min(hdr_len ? hdr_len : GOODCOPY_LEN, good_linear); linear = copylen; iov_iter_advance(&i, copylen); if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
@@ -1820,10 +1819,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, } else { if (!zerocopy) { copylen = len; - if (tun16_to_cpu(tun, gso.hdr_len) > good_linear) - linear = good_linear; - else - linear = tun16_to_cpu(tun, gso.hdr_len); + linear = min(hdr_len, good_linear); } if (frags) {
--
2.47.1