[PATCH net v3 4/9] 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>
---
 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;
 
 		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