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Message-ID: <678a1fd7d7c85_3e503c29449@willemb.c.googlers.com.notmuch>
Date: Fri, 17 Jan 2025 04:16:07 -0500
From: Willem de Bruijn <willemdebruijn.kernel@...il.com>
To: Akihiko Odaki <akihiko.odaki@...nix.com>,
Jonathan Corbet <corbet@....net>,
Willem de Bruijn <willemdebruijn.kernel@...il.com>,
Jason Wang <jasowang@...hat.com>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
"Michael S. Tsirkin" <mst@...hat.com>,
Xuan Zhuo <xuanzhuo@...ux.alibaba.com>,
Shuah Khan <shuah@...nel.org>,
linux-doc@...r.kernel.org,
linux-kernel@...r.kernel.org,
netdev@...r.kernel.org,
kvm@...r.kernel.org,
virtualization@...ts.linux-foundation.org,
linux-kselftest@...r.kernel.org,
Yuri Benditovich <yuri.benditovich@...nix.com>,
Andrew Melnychenko <andrew@...nix.com>,
Stephen Hemminger <stephen@...workplumber.org>,
gur.stavi@...wei.com,
devel@...nix.com,
Akihiko Odaki <akihiko.odaki@...nix.com>
Subject: Re: [PATCH net v3 4/9] tun: Decouple vnet from tun_struct
Akihiko Odaki wrote:
> Decouple vnet-related functions from tun_struct so that we can reuse
> them for tap in the future.
>
> Signed-off-by: Akihiko Odaki <akihiko.odaki@...nix.com>
> ---
> drivers/net/tun.c | 53 +++++++++++++++++++++++++++--------------------------
> 1 file changed, 27 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/net/tun.c b/drivers/net/tun.c
> index ec56ac865848..add09dfdada5 100644
> --- a/drivers/net/tun.c
> +++ b/drivers/net/tun.c
> @@ -298,16 +298,16 @@ static bool tun_napi_frags_enabled(const struct tun_file *tfile)
> return tfile->napi_frags_enabled;
> }
>
> -static inline bool tun_legacy_is_little_endian(struct tun_struct *tun)
> +static inline bool tun_legacy_is_little_endian(unsigned int flags)
> {
> return !(IS_ENABLED(CONFIG_TUN_VNET_CROSS_LE) &&
> - (tun->flags & TUN_VNET_BE)) &&
> + (flags & TUN_VNET_BE)) &&
> virtio_legacy_is_little_endian();
> }
>
> -static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
> +static long tun_get_vnet_be(unsigned int flags, int __user *argp)
> {
> - int be = !!(tun->flags & TUN_VNET_BE);
> + int be = !!(flags & TUN_VNET_BE);
>
> if (!IS_ENABLED(CONFIG_TUN_VNET_CROSS_LE))
> return -EINVAL;
> @@ -318,7 +318,7 @@ static long tun_get_vnet_be(struct tun_struct *tun, int __user *argp)
> return 0;
> }
>
> -static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
> +static long tun_set_vnet_be(unsigned int *flags, int __user *argp)
> {
> int be;
>
> @@ -329,27 +329,26 @@ static long tun_set_vnet_be(struct tun_struct *tun, int __user *argp)
> return -EFAULT;
>
> if (be)
> - tun->flags |= TUN_VNET_BE;
> + *flags |= TUN_VNET_BE;
> else
> - tun->flags &= ~TUN_VNET_BE;
> + *flags &= ~TUN_VNET_BE;
>
> return 0;
> }
>
> -static inline bool tun_is_little_endian(struct tun_struct *tun)
> +static inline bool tun_is_little_endian(unsigned int flags)
> {
> - return tun->flags & TUN_VNET_LE ||
> - tun_legacy_is_little_endian(tun);
> + return flags & TUN_VNET_LE || tun_legacy_is_little_endian(flags);
> }
>
> -static inline u16 tun16_to_cpu(struct tun_struct *tun, __virtio16 val)
> +static inline u16 tun16_to_cpu(unsigned int flags, __virtio16 val)
> {
> - return __virtio16_to_cpu(tun_is_little_endian(tun), val);
> + return __virtio16_to_cpu(tun_is_little_endian(flags), val);
> }
>
> -static inline __virtio16 cpu_to_tun16(struct tun_struct *tun, u16 val)
> +static inline __virtio16 cpu_to_tun16(unsigned int flags, u16 val)
> {
> - return __cpu_to_virtio16(tun_is_little_endian(tun), val);
> + return __cpu_to_virtio16(tun_is_little_endian(flags), val);
> }
>
> static inline u32 tun_hashfn(u32 rxhash)
> @@ -1764,6 +1763,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
>
> if (tun->flags & IFF_VNET_HDR) {
> int vnet_hdr_sz = READ_ONCE(tun->vnet_hdr_sz);
> + int flags = tun->flags;
Here and elsewhere: instead of passing around and repeatedly parsing
flags, have a variable is_little_endian (or is_le)?
>
> if (iov_iter_count(from) < vnet_hdr_sz)
> return -EINVAL;
> @@ -1772,12 +1772,12 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
> return -EFAULT;
>
> if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
> - tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2 > tun16_to_cpu(tun, gso.hdr_len))
> - gso.hdr_len = cpu_to_tun16(tun, tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2);
> + tun16_to_cpu(flags, gso.csum_start) + tun16_to_cpu(flags, gso.csum_offset) + 2 > tun16_to_cpu(flags, gso.hdr_len))
> + gso.hdr_len = cpu_to_tun16(flags, tun16_to_cpu(flags, gso.csum_start) + tun16_to_cpu(flags, gso.csum_offset) + 2);
>
> - if (tun16_to_cpu(tun, gso.hdr_len) > iov_iter_count(from))
> + if (tun16_to_cpu(flags, gso.hdr_len) > iov_iter_count(from))
> return -EINVAL;
> - hdr_len = tun16_to_cpu(tun, gso.hdr_len);
> + hdr_len = tun16_to_cpu(flags, gso.hdr_len);
> iov_iter_advance(from, vnet_hdr_sz - sizeof(gso));
> }
>
> @@ -1854,7 +1854,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
> }
> }
>
> - if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun))) {
> + if (virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun->flags))) {
> atomic_long_inc(&tun->rx_frame_errors);
> err = -EINVAL;
> goto free_skb;
> @@ -2108,23 +2108,24 @@ static ssize_t tun_put_user(struct tun_struct *tun,
>
> if (vnet_hdr_sz) {
> struct virtio_net_hdr gso;
> + int flags = tun->flags;
>
> if (iov_iter_count(iter) < vnet_hdr_sz)
> return -EINVAL;
>
> if (virtio_net_hdr_from_skb(skb, &gso,
> - tun_is_little_endian(tun), true,
> + tun_is_little_endian(flags), true,
> vlan_hlen)) {
> struct skb_shared_info *sinfo = skb_shinfo(skb);
>
> if (net_ratelimit()) {
> netdev_err(tun->dev, "unexpected GSO type: 0x%x, gso_size %d, hdr_len %d\n",
> - sinfo->gso_type, tun16_to_cpu(tun, gso.gso_size),
> - tun16_to_cpu(tun, gso.hdr_len));
> + sinfo->gso_type, tun16_to_cpu(flags, gso.gso_size),
> + tun16_to_cpu(flags, gso.hdr_len));
> print_hex_dump(KERN_ERR, "tun: ",
> DUMP_PREFIX_NONE,
> 16, 1, skb->head,
> - min((int)tun16_to_cpu(tun, gso.hdr_len), 64), true);
> + min((int)tun16_to_cpu(flags, gso.hdr_len), 64), true);
> }
> WARN_ON_ONCE(1);
> return -EINVAL;
> @@ -2493,7 +2494,7 @@ static int tun_xdp_one(struct tun_struct *tun,
> skb_reserve(skb, xdp->data - xdp->data_hard_start);
> skb_put(skb, xdp->data_end - xdp->data);
>
> - if (virtio_net_hdr_to_skb(skb, gso, tun_is_little_endian(tun))) {
> + if (virtio_net_hdr_to_skb(skb, gso, tun_is_little_endian(tun->flags))) {
> atomic_long_inc(&tun->rx_frame_errors);
> kfree_skb(skb);
> ret = -EINVAL;
> @@ -3322,11 +3323,11 @@ static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
> break;
>
> case TUNGETVNETBE:
> - ret = tun_get_vnet_be(tun, argp);
> + ret = tun_get_vnet_be(tun->flags, argp);
> break;
>
> case TUNSETVNETBE:
> - ret = tun_set_vnet_be(tun, argp);
> + ret = tun_set_vnet_be(&tun->flags, argp);
> break;
>
> case TUNATTACHFILTER:
>
> --
> 2.47.1
>
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