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Subject[PATCH v2 08/17] {macvtap,tun}_get_user(): switch to iov_iter
Date
From: Al Viro <viro@zeniv.linux.org.uk>

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

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
drivers/net/macvtap.c | 44 +++++++++++++++++++++-----------------------
drivers/net/tun.c | 44 ++++++++++++++++++++++++--------------------
2 files changed, 45 insertions(+), 43 deletions(-)

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 8f80045..22b4cf2 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,
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 405dfdf..4b743c6 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1012,28 +1012,29 @@ static struct sk_buff *tun_alloc_skb(struct tun_file *tfile,

/* Get packet from user space buffer */
static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
- void *msg_control, const struct iovec *iv,
- size_t total_len, size_t count, int noblock)
+ void *msg_control, struct iov_iter *from,
+ int noblock)
{
struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
struct sk_buff *skb;
+ size_t total_len = iov_iter_count(from);
size_t len = total_len, align = NET_SKB_PAD, linear;
struct virtio_net_hdr gso = { 0 };
int good_linear;
- int offset = 0;
int copylen;
bool zerocopy = false;
int err;
u32 rxhash;
+ ssize_t n;

if (!(tun->flags & TUN_NO_PI)) {
if (len < sizeof(pi))
return -EINVAL;
len -= sizeof(pi);

- if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
+ n = copy_from_iter(&pi, sizeof(pi), from);
+ if (n != sizeof(pi))
return -EFAULT;
- offset += sizeof(pi);
}

if (tun->flags & TUN_VNET_HDR) {
@@ -1041,7 +1042,8 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
return -EINVAL;
len -= tun->vnet_hdr_sz;

- if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
+ n = copy_from_iter(&gso, sizeof(gso), from);
+ if (n != sizeof(gso))
return -EFAULT;

if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
@@ -1050,7 +1052,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,

if (gso.hdr_len > len)
return -EINVAL;
- offset += tun->vnet_hdr_sz;
+ iov_iter_advance(from, tun->vnet_hdr_sz);
}

if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
@@ -1063,6 +1065,8 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
good_linear = SKB_MAX_HEAD(align);

if (msg_control) {
+ struct iov_iter i = *from;
+
/* There are 256 bytes to be copied in skb, so there is
* enough room for skb expand head in case it is used.
* The rest of the buffer is mapped from userspace.
@@ -1071,7 +1075,8 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
if (copylen > good_linear)
copylen = good_linear;
linear = copylen;
- if (iov_pages(iv, offset + copylen, count) <= MAX_SKB_FRAGS)
+ iov_iter_advance(&i, copylen);
+ if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
zerocopy = true;
}

@@ -1091,9 +1096,9 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
}

if (zerocopy)
- err = zerocopy_sg_from_iovec(skb, iv, offset, count);
+ err = zerocopy_sg_from_iter(skb, from);
else {
- err = skb_copy_datagram_from_iovec(skb, 0, iv, offset, len);
+ err = skb_copy_datagram_from_iter(skb, 0, from, len);
if (!err && msg_control) {
struct ubuf_info *uarg = msg_control;
uarg->callback(uarg, false);
@@ -1207,8 +1212,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
return total_len;
}

-static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
- unsigned long count, loff_t pos)
+static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
struct tun_struct *tun = tun_get(file);
@@ -1218,10 +1222,7 @@ static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
if (!tun)
return -EBADFD;

- tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count);
-
- result = tun_get_user(tun, tfile, NULL, iv, iov_length(iv, count),
- count, file->f_flags & O_NONBLOCK);
+ result = tun_get_user(tun, tfile, NULL, from, file->f_flags & O_NONBLOCK);

tun_put(tun);
return result;
@@ -1445,11 +1446,14 @@ static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
int ret;
struct tun_file *tfile = container_of(sock, struct tun_file, socket);
struct tun_struct *tun = __tun_get(tfile);
+ struct iov_iter from;

if (!tun)
return -EBADFD;
- ret = tun_get_user(tun, tfile, m->msg_control, m->msg_iov, total_len,
- m->msg_iovlen, m->msg_flags & MSG_DONTWAIT);
+
+ iov_iter_init(&from, WRITE, m->msg_iov, m->msg_iovlen, total_len);
+ ret = tun_get_user(tun, tfile, m->msg_control, &from,
+ m->msg_flags & MSG_DONTWAIT);
tun_put(tun);
return ret;
}
@@ -2233,9 +2237,9 @@ static const struct file_operations tun_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.read = new_sync_read,
+ .write = new_sync_write,
.read_iter = tun_chr_read_iter,
- .write = do_sync_write,
- .aio_write = tun_chr_aio_write,
+ .write_iter = tun_chr_write_iter,
.poll = tun_chr_poll,
.unlocked_ioctl = tun_chr_ioctl,
#ifdef CONFIG_COMPAT
--
1.7.10.4


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