[PATCH net-next v6 3/7] tun: Decouple vnet from tun_struct

[Akihiko Odaki <akihiko.odaki@daynix.com>]

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@daynix.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
---
 drivers/net/tun.c | 51 ++++++++++++++++++++++++++-------------------------
 1 file changed, 26 insertions(+), 25 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index c204c1c0d75bc7d336ec315099a5a60d5d70ea82..28a1af1de9d704ed5cc51aac3d99bc095cb28ba5 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -298,17 +298,17 @@ 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)
 {
 	bool be = IS_ENABLED(CONFIG_TUN_VNET_CROSS_LE) &&
-		  (tun->flags & TUN_VNET_BE);
+		  (flags & TUN_VNET_BE);
 
 	return !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;
@@ -319,7 +319,7 @@ 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;
 
@@ -330,27 +330,26 @@ 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)
@@ -1766,6 +1765,7 @@ 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;
 
 		if (len < vnet_hdr_sz)
 			return -EINVAL;
@@ -1774,11 +1774,11 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 		if (!copy_from_iter_full(&gso, sizeof(gso), from))
 			return -EFAULT;
 
-		hdr_len = tun16_to_cpu(tun, gso.hdr_len);
+		hdr_len = tun16_to_cpu(flags, gso.hdr_len);
 
 		if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
-			hdr_len = max(tun16_to_cpu(tun, gso.csum_start) + tun16_to_cpu(tun, gso.csum_offset) + 2, hdr_len);
-			gso.hdr_len = cpu_to_tun16(tun, hdr_len);
+			hdr_len = max(tun16_to_cpu(flags, gso.csum_start) + tun16_to_cpu(flags, gso.csum_offset) + 2, hdr_len);
+			gso.hdr_len = cpu_to_tun16(flags, hdr_len);
 		}
 
 		if (hdr_len > len)
@@ -1857,7 +1857,7 @@ 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;
@@ -2111,23 +2111,24 @@ 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;
@@ -2496,7 +2497,7 @@ 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;
@@ -3325,11 +3326,11 @@ 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:

-- 
2.48.1