tun: Use iovec iterators

This patch removes the use of skb_copy_datagram_const_iovec in
favour of the iovec iterator-based skb_copy_datagram_iter.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 30 insertions, 35 deletions

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 9dd3746994a4..2ff769bf3f35 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -71,6 +71,7 @@
 #include <net/rtnetlink.h>
 #include <net/sock.h>
 #include <linux/seq_file.h>
+#include <linux/uio.h>
 
 #include <asm/uaccess.h>
 
@@ -1230,11 +1231,11 @@ static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
 static ssize_t tun_put_user(struct tun_struct *tun,
                             struct tun_file *tfile,
                             struct sk_buff *skb,
-                            const struct iovec *iv, int len)
+                            struct iov_iter *iter)
 {
         struct tun_pi pi = { 0, skb->protocol };
-        ssize_t total = 0;
-        int vlan_offset = 0, copied;
+        ssize_t total;
+        int vlan_offset;
         int vlan_hlen = 0;
         int vnet_hdr_sz = 0;
 
@@ -1244,23 +1245,25 @@ static ssize_t tun_put_user(struct tun_struct *tun,
         if (tun->flags & TUN_VNET_HDR)
                 vnet_hdr_sz = tun->vnet_hdr_sz;
 
+        total = skb->len + vlan_hlen + vnet_hdr_sz;
+
         if (!(tun->flags & TUN_NO_PI)) {
-                if ((len -= sizeof(pi)) < 0)
+                if (iov_iter_count(iter) < sizeof(pi))
                         return -EINVAL;
 
-                if (len < skb->len + vlan_hlen + vnet_hdr_sz) {
+                total += sizeof(pi);
+                if (iov_iter_count(iter) < total) {
                         /* Packet will be striped */
                         pi.flags |= TUN_PKT_STRIP;
                 }
 
-                if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
+                if (copy_to_iter(&pi, sizeof(pi), iter) != sizeof(pi))
                         return -EFAULT;
-                total += sizeof(pi);
         }
 
         if (vnet_hdr_sz) {
                 struct virtio_net_hdr gso = { 0 }; /* no info leak */
-                if ((len -= vnet_hdr_sz) < 0)
+                if (iov_iter_count(iter) < vnet_hdr_sz)
                         return -EINVAL;
 
                 if (skb_is_gso(skb)) {
@@ -1299,17 +1302,12 @@ static ssize_t tun_put_user(struct tun_struct *tun,
                         gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
                 } /* else everything is zero */
 
-                if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
-                                               sizeof(gso))))
+                if (copy_to_iter(&gso, sizeof(gso), iter) != sizeof(gso))
                         return -EFAULT;
-                total += vnet_hdr_sz;
         }
 
-        copied = total;
-        len = min_t(int, skb->len + vlan_hlen, len);
-        total += skb->len + vlan_hlen;
         if (vlan_hlen) {
-                int copy, ret;
+                int ret;
                 struct {
                         __be16 h_vlan_proto;
                         __be16 h_vlan_TCI;
@@ -1320,36 +1318,32 @@ static ssize_t tun_put_user(struct tun_struct *tun,
 
                 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
 
-                copy = min_t(int, vlan_offset, len);
-                ret = skb_copy_datagram_const_iovec(skb, 0, iv, copied, copy);
-                len -= copy;
-                copied += copy;
-                if (ret || !len)
+                ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
+                if (ret || !iov_iter_count(iter))
                         goto done;
 
-                copy = min_t(int, sizeof(veth), len);
-                ret = memcpy_toiovecend(iv, (void *)&veth, copied, copy);
-                len -= copy;
-                copied += copy;
-                if (ret || !len)
+                ret = copy_to_iter(&veth, sizeof(veth), iter);
+                if (ret != sizeof(veth) || !iov_iter_count(iter))
                         goto done;
         }
 
-        skb_copy_datagram_const_iovec(skb, vlan_offset, iv, copied, len);
+        skb_copy_datagram_iter(skb, vlan_offset, iter, skb->len - vlan_offset);
 
 done:
         tun->dev->stats.tx_packets++;
-        tun->dev->stats.tx_bytes += len;
+        tun->dev->stats.tx_bytes += skb->len + vlan_hlen;
 
         return total;
 }
 
 static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
-                           const struct iovec *iv, ssize_t len, int noblock)
+                           const struct iovec *iv, unsigned long segs,
+                           ssize_t len, int noblock)
 {
         struct sk_buff *skb;
         ssize_t ret = 0;
         int peeked, err, off = 0;
+        struct iov_iter iter;
 
         tun_debug(KERN_INFO, tun, "tun_do_read\n");
 
@@ -1362,11 +1356,12 @@ static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
         /* Read frames from queue */
         skb = __skb_recv_datagram(tfile->socket.sk, noblock ? MSG_DONTWAIT : 0,
                                   &peeked, &off, &err);
-        if (skb) {
-                ret = tun_put_user(tun, tfile, skb, iv, len);
-                kfree_skb(skb);
-        } else
-                ret = err;
+        if (!skb)
+                return ret;
+
+        iov_iter_init(&iter, READ, iv, segs, len);
+        ret = tun_put_user(tun, tfile, skb, &iter);
+        kfree_skb(skb);
 
         return ret;
 }
@@ -1387,7 +1382,7 @@ static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
                 goto out;
         }
 
-        ret = tun_do_read(tun, tfile, iv, len,
+        ret = tun_do_read(tun, tfile, iv, count, len,
                           file->f_flags & O_NONBLOCK);
         ret = min_t(ssize_t, ret, len);
         if (ret > 0)
@@ -1488,7 +1483,7 @@ static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
                                          SOL_PACKET, TUN_TX_TIMESTAMP);
                 goto out;
         }
-        ret = tun_do_read(tun, tfile, m->msg_iov, total_len,
+        ret = tun_do_read(tun, tfile, m->msg_iov, m->msg_iovlen, total_len,
                           flags & MSG_DONTWAIT);
         if (ret > total_len) {
                 m->msg_flags |= MSG_TRUNC;