[PATCH 3/4] macvtap: Use iovec iterators

From: Herbert Xu
Date: Tue Nov 04 2014 - 03:32:30 EST


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@xxxxxxxxxxxxxxxxxxx>
---

drivers/net/macvtap.c | 45 ++++++++++++++++++++-------------------------
1 file changed, 20 insertions(+), 25 deletions(-)

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 880cc09..a0e1dd7 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -15,6 +15,7 @@
#include <linux/cdev.h>
#include <linux/idr.h>
#include <linux/fs.h>
+#include <linux/uio.h>

#include <net/ipv6.h>
#include <net/net_namespace.h>
@@ -778,31 +779,28 @@ static ssize_t macvtap_aio_write(struct kiocb *iocb, const struct iovec *iv,
/* Put packet to the user space buffer */
static ssize_t macvtap_put_user(struct macvtap_queue *q,
const struct sk_buff *skb,
- const struct iovec *iv, int len)
+ struct iov_iter *iter)
{
int ret;
int vnet_hdr_len = 0;
int vlan_offset = 0;
- int copied, total;
+ int total;

if (q->flags & IFF_VNET_HDR) {
struct virtio_net_hdr vnet_hdr;
vnet_hdr_len = q->vnet_hdr_sz;
- if ((len -= vnet_hdr_len) < 0)
+ if (iov_iter_count(iter) < vnet_hdr_len)
return -EINVAL;

macvtap_skb_to_vnet_hdr(skb, &vnet_hdr);

- if (memcpy_toiovecend(iv, (void *)&vnet_hdr, 0, sizeof(vnet_hdr)))
+ if (copy_to_iter(&vnet_hdr, sizeof(vnet_hdr), iter))
return -EFAULT;
}
- total = copied = vnet_hdr_len;
+ total = vnet_hdr_len;
total += skb->len;

- if (!vlan_tx_tag_present(skb))
- len = min_t(int, skb->len, len);
- else {
- int copy;
+ if (vlan_tx_tag_present(skb)) {
struct {
__be16 h_vlan_proto;
__be16 h_vlan_TCI;
@@ -811,37 +809,33 @@ static ssize_t macvtap_put_user(struct macvtap_queue *q,
veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb));

vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
- len = min_t(int, skb->len + VLAN_HLEN, len);
total += VLAN_HLEN;

- 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 || !iov_iter_count(iter))
goto done;
}

- ret = skb_copy_datagram_const_iovec(skb, vlan_offset, iv, copied, len);
+ ret = skb_copy_datagram_iter(skb, vlan_offset, iter,
+ skb->len - vlan_offset);

done:
return ret ? ret : total;
}

static ssize_t macvtap_do_read(struct macvtap_queue *q,
- const struct iovec *iv, unsigned long len,
+ const struct iovec *iv, unsigned long segs,
+ unsigned long len,
int noblock)
{
DEFINE_WAIT(wait);
struct sk_buff *skb;
ssize_t ret = 0;
+ struct iov_iter iter;

while (len) {
if (!noblock)
@@ -863,7 +857,8 @@ static ssize_t macvtap_do_read(struct macvtap_queue *q,
schedule();
continue;
}
- ret = macvtap_put_user(q, skb, iv, len);
+ iov_iter_init(&iter, READ, iv, segs, len);
+ ret = macvtap_put_user(q, skb, &iter);
kfree_skb(skb);
break;
}
@@ -886,7 +881,7 @@ static ssize_t macvtap_aio_read(struct kiocb *iocb, const struct iovec *iv,
goto out;
}

- ret = macvtap_do_read(q, iv, len, file->f_flags & O_NONBLOCK);
+ ret = macvtap_do_read(q, iv, count, len, file->f_flags & O_NONBLOCK);
ret = min_t(ssize_t, ret, len);
if (ret > 0)
iocb->ki_pos = ret;
@@ -1117,7 +1112,7 @@ static int macvtap_recvmsg(struct kiocb *iocb, struct socket *sock,
int ret;
if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
return -EINVAL;
- ret = macvtap_do_read(q, m->msg_iov, total_len,
+ ret = macvtap_do_read(q, m->msg_iov, m->msg_iovlen, total_len,
flags & MSG_DONTWAIT);
if (ret > total_len) {
m->msg_flags |= MSG_TRUNC;
--
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