{macvtap,tun}_get_user(): switch to iov_iter

allows to switch macvtap and tun from ->aio_write() to ->write_iter()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 21 insertions, 23 deletions

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 8f8004552d8e..22b4cf2fa108 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -640,12 +640,12 @@ static void macvtap_skb_to_vnet_hdr(const struct sk_buff *skb,
 
 /* Get packet from user space buffer */
 static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
-                                const struct iovec *iv, unsigned long total_len,
-                                size_t count, int noblock)
+                                struct iov_iter *from, int noblock)
 {
         int good_linear = SKB_MAX_HEAD(NET_IP_ALIGN);
         struct sk_buff *skb;
         struct macvlan_dev *vlan;
+        unsigned long total_len = iov_iter_count(from);
         unsigned long len = total_len;
         int err;
         struct virtio_net_hdr vnet_hdr = { 0 };
@@ -653,6 +653,7 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
         int copylen = 0;
         bool zerocopy = false;
         size_t linear;
+        ssize_t n;
 
         if (q->flags & IFF_VNET_HDR) {
                 vnet_hdr_len = q->vnet_hdr_sz;
@@ -662,10 +663,11 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
                         goto err;
                 len -= vnet_hdr_len;
 
-                err = memcpy_fromiovecend((void *)&vnet_hdr, iv, 0,
-                                           sizeof(vnet_hdr));
-                if (err < 0)
+                err = -EFAULT;
+                n = copy_from_iter(&vnet_hdr, sizeof(vnet_hdr), from);
+                if (n != sizeof(vnet_hdr))
                         goto err;
+                iov_iter_advance(from, vnet_hdr_len - sizeof(vnet_hdr));
                 if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
                      vnet_hdr.csum_start + vnet_hdr.csum_offset + 2 >
                                                         vnet_hdr.hdr_len)
@@ -680,17 +682,16 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
         if (unlikely(len < ETH_HLEN))
                 goto err;
 
-        err = -EMSGSIZE;
-        if (unlikely(count > UIO_MAXIOV))
-                goto err;
-
         if (m && m->msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY)) {
+                struct iov_iter i;
+
                 copylen = vnet_hdr.hdr_len ? vnet_hdr.hdr_len : GOODCOPY_LEN;
                 if (copylen > good_linear)
                         copylen = good_linear;
                 linear = copylen;
-                if (iov_pages(iv, vnet_hdr_len + copylen, count)
-                    <= MAX_SKB_FRAGS)
+                i = *from;
+                iov_iter_advance(&i, copylen);
+                if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
                         zerocopy = true;
         }
 
@@ -708,10 +709,9 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
                 goto err;
 
         if (zerocopy)
-                err = zerocopy_sg_from_iovec(skb, iv, vnet_hdr_len, count);
+                err = zerocopy_sg_from_iter(skb, from);
         else {
-                err = skb_copy_datagram_from_iovec(skb, 0, iv, vnet_hdr_len,
-                                                   len);
+                err = skb_copy_datagram_from_iter(skb, 0, from, len);
                 if (!err && m && m->msg_control) {
                         struct ubuf_info *uarg = m->msg_control;
                         uarg->callback(uarg, false);
@@ -764,16 +764,12 @@ err:
         return err;
 }
 
-static ssize_t macvtap_aio_write(struct kiocb *iocb, const struct iovec *iv,
-                                 unsigned long count, loff_t pos)
+static ssize_t macvtap_write_iter(struct kiocb *iocb, struct iov_iter *from)
 {
         struct file *file = iocb->ki_filp;
-        ssize_t result = -ENOLINK;
         struct macvtap_queue *q = file->private_data;
 
-        result = macvtap_get_user(q, NULL, iv, iov_length(iv, count), count,
-                                  file->f_flags & O_NONBLOCK);
-        return result;
+        return macvtap_get_user(q, NULL, from, file->f_flags & O_NONBLOCK);
 }
 
 /* Put packet to the user space buffer */
@@ -1081,8 +1077,9 @@ static const struct file_operations macvtap_fops = {
         .open           = macvtap_open,
         .release        = macvtap_release,
         .read           = new_sync_read,
+        .write          = new_sync_write,
         .read_iter      = macvtap_read_iter,
-        .aio_write      = macvtap_aio_write,
+        .write_iter     = macvtap_write_iter,
         .poll           = macvtap_poll,
         .llseek         = no_llseek,
         .unlocked_ioctl = macvtap_ioctl,
@@ -1095,8 +1092,9 @@ static int macvtap_sendmsg(struct kiocb *iocb, struct socket *sock,
                            struct msghdr *m, size_t total_len)
 {
         struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
-        return macvtap_get_user(q, m, m->msg_iov, total_len, m->msg_iovlen,
-                            m->msg_flags & MSG_DONTWAIT);
+        struct iov_iter from;
+        iov_iter_init(&from, WRITE, m->msg_iov, m->msg_iovlen, total_len);
+        return macvtap_get_user(q, m, &from, m->msg_flags & MSG_DONTWAIT);
 }
 
 static int macvtap_recvmsg(struct kiocb *iocb, struct socket *sock,