[PATCH net-next 1/2] tun/tap: use ptr_ring instead of skb_array

From: Jason Wang
Date: Fri Dec 29 2017 - 05:00:27 EST

This patch switches to use ptr_ring instead of skb_array. This will be
used to enqueue different types of pointers by encoding type into
lower bits.

Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
drivers/net/tap.c | 41 +++++++++++++++++++++--------------------
drivers/net/tun.c | 42 ++++++++++++++++++++++--------------------
drivers/vhost/net.c | 39 ++++++++++++++++++++-------------------
include/linux/if_tap.h | 6 +++---
include/linux/if_tun.h | 4 ++--
5 files changed, 68 insertions(+), 64 deletions(-)

diff --git a/drivers/net/tap.c b/drivers/net/tap.c
index 0a886fda..7c38659 100644
--- a/drivers/net/tap.c
+++ b/drivers/net/tap.c
@@ -330,7 +330,7 @@ rx_handler_result_t tap_handle_frame(struct sk_buff **pskb)
if (!q)
return RX_HANDLER_PASS;

- if (__skb_array_full(&q->skb_array))
+ if (__ptr_ring_full(&q->ring))
goto drop;

skb_push(skb, ETH_HLEN);
@@ -348,7 +348,7 @@ rx_handler_result_t tap_handle_frame(struct sk_buff **pskb)
goto drop;

if (!segs) {
- if (skb_array_produce(&q->skb_array, skb))
+ if (ptr_ring_produce(&q->ring, skb))
goto drop;
goto wake_up;
}
@@ -358,7 +358,7 @@ rx_handler_result_t tap_handle_frame(struct sk_buff **pskb)
struct sk_buff *nskb = segs->next;

segs->next = NULL;
- if (skb_array_produce(&q->skb_array, segs)) {
+ if (ptr_ring_produce(&q->ring, segs)) {
kfree_skb(segs);
kfree_skb_list(nskb);
break;
@@ -375,7 +375,7 @@ rx_handler_result_t tap_handle_frame(struct sk_buff **pskb)
!(features & NETIF_F_CSUM_MASK) &&
skb_checksum_help(skb))
goto drop;
- if (skb_array_produce(&q->skb_array, skb))
+ if (ptr_ring_produce(&q->ring, skb))
goto drop;
}

@@ -497,7 +497,7 @@ static void tap_sock_destruct(struct sock *sk)
{
struct tap_queue *q = container_of(sk, struct tap_queue, sk);

- skb_array_cleanup(&q->skb_array);
+ ptr_ring_cleanup(&q->ring, __skb_array_destroy_skb);
}

static int tap_open(struct inode *inode, struct file *file)
@@ -517,7 +517,7 @@ static int tap_open(struct inode *inode, struct file *file)
&tap_proto, 0);
if (!q)
goto err;
- if (skb_array_init(&q->skb_array, tap->dev->tx_queue_len, GFP_KERNEL)) {
+ if (ptr_ring_init(&q->ring, tap->dev->tx_queue_len, GFP_KERNEL)) {
sk_free(&q->sk);
goto err;
}
@@ -546,7 +546,7 @@ static int tap_open(struct inode *inode, struct file *file)

err = tap_set_queue(tap, file, q);
if (err) {
- /* tap_sock_destruct() will take care of freeing skb_array */
+ /* tap_sock_destruct() will take care of freeing ptr_ring */
goto err_put;
}

@@ -583,7 +583,7 @@ static unsigned int tap_poll(struct file *file, poll_table *wait)
mask = 0;
poll_wait(file, &q->wq.wait, wait);

- if (!skb_array_empty(&q->skb_array))
+ if (!ptr_ring_empty(&q->ring))
mask |= POLLIN | POLLRDNORM;

if (sock_writeable(&q->sk) ||
@@ -844,7 +844,7 @@ static ssize_t tap_do_read(struct tap_queue *q,
TASK_INTERRUPTIBLE);

/* Read frames from the queue */
- skb = skb_array_consume(&q->skb_array);
+ skb = ptr_ring_consume(&q->ring);
if (skb)
break;
if (noblock) {
@@ -1176,7 +1176,7 @@ static int tap_peek_len(struct socket *sock)
{
struct tap_queue *q = container_of(sock, struct tap_queue,
sock);
- return skb_array_peek_len(&q->skb_array);
+ return PTR_RING_PEEK_CALL(&q->ring, __skb_array_len_with_tag);
}

/* Ops structure to mimic raw sockets with tun */
@@ -1202,7 +1202,7 @@ struct socket *tap_get_socket(struct file *file)
}
EXPORT_SYMBOL_GPL(tap_get_socket);

-struct skb_array *tap_get_skb_array(struct file *file)
+struct ptr_ring *tap_get_ptr_ring(struct file *file)
{
struct tap_queue *q;

@@ -1211,29 +1211,30 @@ struct skb_array *tap_get_skb_array(struct file *file)
q = file->private_data;
if (!q)
return ERR_PTR(-EBADFD);
- return &q->skb_array;
+ return &q->ring;
}
-EXPORT_SYMBOL_GPL(tap_get_skb_array);
+EXPORT_SYMBOL_GPL(tap_get_ptr_ring);

int tap_queue_resize(struct tap_dev *tap)
{
struct net_device *dev = tap->dev;
struct tap_queue *q;
- struct skb_array **arrays;
+ struct ptr_ring **rings;
int n = tap->numqueues;
int ret, i = 0;

- arrays = kmalloc_array(n, sizeof(*arrays), GFP_KERNEL);
- if (!arrays)
+ rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
+ if (!rings)
return -ENOMEM;

list_for_each_entry(q, &tap->queue_list, next)
- arrays[i++] = &q->skb_array;
+ rings[i++] = &q->ring;

- ret = skb_array_resize_multiple(arrays, n,
- dev->tx_queue_len, GFP_KERNEL);
+ ret = ptr_ring_resize_multiple(rings, n,
+ dev->tx_queue_len, GFP_KERNEL,
+ __skb_array_destroy_skb);

- kfree(arrays);
+ kfree(rings);
return ret;
}
EXPORT_SYMBOL_GPL(tap_queue_resize);
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index e367d631..2c89efe 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -179,7 +179,7 @@ struct tun_file {
struct mutex napi_mutex; /* Protects access to the above napi */
struct list_head next;
struct tun_struct *detached;
- struct skb_array tx_array;
+ struct ptr_ring tx_ring;
};

struct tun_flow_entry {
@@ -634,7 +634,7 @@ static void tun_queue_purge(struct tun_file *tfile)
{
struct sk_buff *skb;

- while ((skb = skb_array_consume(&tfile->tx_array)) != NULL)
+ while ((skb = ptr_ring_consume(&tfile->tx_ring)) != NULL)
kfree_skb(skb);

skb_queue_purge(&tfile->sk.sk_write_queue);
@@ -688,7 +688,8 @@ static void __tun_detach(struct tun_file *tfile, bool clean)
unregister_netdevice(tun->dev);
}
if (tun)
- skb_array_cleanup(&tfile->tx_array);
+ ptr_ring_cleanup(&tfile->tx_ring,
+ __skb_array_destroy_skb);
sock_put(&tfile->sk);
}
}
@@ -777,7 +778,7 @@ static int tun_attach(struct tun_struct *tun, struct file *file,
}

if (!tfile->detached &&
- skb_array_init(&tfile->tx_array, dev->tx_queue_len, GFP_KERNEL)) {
+ ptr_ring_init(&tfile->tx_ring, dev->tx_queue_len, GFP_KERNEL)) {
err = -ENOMEM;
goto out;
}
@@ -1027,7 +1028,7 @@ static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)

nf_reset(skb);

- if (skb_array_produce(&tfile->tx_array, skb))
+ if (ptr_ring_produce(&tfile->tx_ring, skb))
goto drop;

/* Notify and wake up reader process */
@@ -1295,7 +1296,7 @@ static unsigned int tun_chr_poll(struct file *file, poll_table *wait)

poll_wait(file, sk_sleep(sk), wait);

- if (!skb_array_empty(&tfile->tx_array))
+ if (!ptr_ring_empty(&tfile->tx_ring))
mask |= POLLIN | POLLRDNORM;

if (tun->dev->flags & IFF_UP &&
@@ -1944,7 +1945,7 @@ static struct sk_buff *tun_ring_recv(struct tun_file *tfile, int noblock,
struct sk_buff *skb = NULL;
int error = 0;

- skb = skb_array_consume(&tfile->tx_array);
+ skb = ptr_ring_consume(&tfile->tx_ring);
if (skb)
goto out;
if (noblock) {
@@ -1956,7 +1957,7 @@ static struct sk_buff *tun_ring_recv(struct tun_file *tfile, int noblock,
current->state = TASK_INTERRUPTIBLE;

while (1) {
- skb = skb_array_consume(&tfile->tx_array);
+ skb = ptr_ring_consume(&tfile->tx_ring);
if (skb)
break;
if (signal_pending(current)) {
@@ -2186,7 +2187,7 @@ static int tun_peek_len(struct socket *sock)
if (!tun)
return 0;

- ret = skb_array_peek_len(&tfile->tx_array);
+ ret = PTR_RING_PEEK_CALL(&tfile->tx_ring, __skb_array_len_with_tag);
tun_put(tun);

return ret;
@@ -3092,25 +3093,26 @@ static int tun_queue_resize(struct tun_struct *tun)
{
struct net_device *dev = tun->dev;
struct tun_file *tfile;
- struct skb_array **arrays;
+ struct ptr_ring **rings;
int n = tun->numqueues + tun->numdisabled;
int ret, i;

- arrays = kmalloc_array(n, sizeof(*arrays), GFP_KERNEL);
- if (!arrays)
+ rings = kmalloc_array(n, sizeof(*rings), GFP_KERNEL);
+ if (!rings)
return -ENOMEM;

for (i = 0; i < tun->numqueues; i++) {
tfile = rtnl_dereference(tun->tfiles[i]);
- arrays[i] = &tfile->tx_array;
+ rings[i] = &tfile->tx_ring;
}
list_for_each_entry(tfile, &tun->disabled, next)
- arrays[i++] = &tfile->tx_array;
+ rings[i++] = &tfile->tx_ring;

- ret = skb_array_resize_multiple(arrays, n,
- dev->tx_queue_len, GFP_KERNEL);
+ ret = ptr_ring_resize_multiple(rings, n,
+ dev->tx_queue_len, GFP_KERNEL,
+ __skb_array_destroy_skb);

- kfree(arrays);
+ kfree(rings);
return ret;
}

@@ -3196,7 +3198,7 @@ struct socket *tun_get_socket(struct file *file)
}
EXPORT_SYMBOL_GPL(tun_get_socket);

-struct skb_array *tun_get_skb_array(struct file *file)
+struct ptr_ring *tun_get_tx_ring(struct file *file)
{
struct tun_file *tfile;

@@ -3205,9 +3207,9 @@ struct skb_array *tun_get_skb_array(struct file *file)
tfile = file->private_data;
if (!tfile)
return ERR_PTR(-EBADFD);
- return &tfile->tx_array;
+ return &tfile->tx_ring;
}
-EXPORT_SYMBOL_GPL(tun_get_skb_array);
+EXPORT_SYMBOL_GPL(tun_get_tx_ring);

module_init(tun_init);
module_exit(tun_cleanup);
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index c7bdeb6..c316555 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -89,7 +89,7 @@ struct vhost_net_ubuf_ref {

#define VHOST_RX_BATCH 64
struct vhost_net_buf {
- struct sk_buff **queue;
+ void **queue;
int tail;
int head;
};
@@ -108,7 +108,7 @@ struct vhost_net_virtqueue {
/* Reference counting for outstanding ubufs.
* Protected by vq mutex. Writers must also take device mutex. */
struct vhost_net_ubuf_ref *ubufs;
- struct skb_array *rx_array;
+ struct ptr_ring *rx_ring;
struct vhost_net_buf rxq;
};

@@ -158,7 +158,7 @@ static int vhost_net_buf_produce(struct vhost_net_virtqueue *nvq)
struct vhost_net_buf *rxq = &nvq->rxq;

rxq->head = 0;
- rxq->tail = skb_array_consume_batched(nvq->rx_array, rxq->queue,
+ rxq->tail = ptr_ring_consume_batched(nvq->rx_ring, rxq->queue,
VHOST_RX_BATCH);
return rxq->tail;
}
@@ -167,9 +167,10 @@ static void vhost_net_buf_unproduce(struct vhost_net_virtqueue *nvq)
{
struct vhost_net_buf *rxq = &nvq->rxq;

- if (nvq->rx_array && !vhost_net_buf_is_empty(rxq)) {
- skb_array_unconsume(nvq->rx_array, rxq->queue + rxq->head,
- vhost_net_buf_get_size(rxq));
+ if (nvq->rx_ring && !vhost_net_buf_is_empty(rxq)) {
+ ptr_ring_unconsume(nvq->rx_ring, rxq->queue + rxq->head,
+ vhost_net_buf_get_size(rxq),
+ __skb_array_destroy_skb);
rxq->head = rxq->tail = 0;
}
}
@@ -583,7 +584,7 @@ static int peek_head_len(struct vhost_net_virtqueue *rvq, struct sock *sk)
int len = 0;
unsigned long flags;

- if (rvq->rx_array)
+ if (rvq->rx_ring)
return vhost_net_buf_peek(rvq);

spin_lock_irqsave(&sk->sk_receive_queue.lock, flags);
@@ -790,7 +791,7 @@ static void handle_rx(struct vhost_net *net)
* they refilled. */
goto out;
}
- if (nvq->rx_array)
+ if (nvq->rx_ring)
msg.msg_control = vhost_net_buf_consume(&nvq->rxq);
/* On overrun, truncate and discard */
if (unlikely(headcount > UIO_MAXIOV)) {
@@ -896,7 +897,7 @@ static int vhost_net_open(struct inode *inode, struct file *f)
struct vhost_net *n;
struct vhost_dev *dev;
struct vhost_virtqueue **vqs;
- struct sk_buff **queue;
+ void **queue;
int i;

n = kvmalloc(sizeof *n, GFP_KERNEL | __GFP_RETRY_MAYFAIL);
@@ -908,7 +909,7 @@ static int vhost_net_open(struct inode *inode, struct file *f)
return -ENOMEM;
}

- queue = kmalloc_array(VHOST_RX_BATCH, sizeof(struct sk_buff *),
+ queue = kmalloc_array(VHOST_RX_BATCH, sizeof(void *),
GFP_KERNEL);
if (!queue) {
kfree(vqs);
@@ -1046,23 +1047,23 @@ static struct socket *get_raw_socket(int fd)
return ERR_PTR(r);
}

-static struct skb_array *get_tap_skb_array(int fd)
+static struct ptr_ring *get_tap_ptr_ring(int fd)
{
- struct skb_array *array;
+ struct ptr_ring *ring;
struct file *file = fget(fd);

if (!file)
return NULL;
- array = tun_get_skb_array(file);
- if (!IS_ERR(array))
+ ring = tun_get_tx_ring(file);
+ if (!IS_ERR(ring))
goto out;
- array = tap_get_skb_array(file);
- if (!IS_ERR(array))
+ ring = tap_get_ptr_ring(file);
+ if (!IS_ERR(ring))
goto out;
- array = NULL;
+ ring = NULL;
out:
fput(file);
- return array;
+ return ring;
}

static struct socket *get_tap_socket(int fd)
@@ -1143,7 +1144,7 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
vq->private_data = sock;
vhost_net_buf_unproduce(nvq);
if (index == VHOST_NET_VQ_RX)
- nvq->rx_array = get_tap_skb_array(fd);
+ nvq->rx_ring = get_tap_ptr_ring(fd);
r = vhost_vq_init_access(vq);
if (r)
goto err_used;
diff --git a/include/linux/if_tap.h b/include/linux/if_tap.h
index 3ecef57..8e66866 100644
--- a/include/linux/if_tap.h
+++ b/include/linux/if_tap.h
@@ -4,7 +4,7 @@

#if IS_ENABLED(CONFIG_TAP)
struct socket *tap_get_socket(struct file *);
-struct skb_array *tap_get_skb_array(struct file *file);
+struct ptr_ring *tap_get_ptr_ring(struct file *file);
#else
#include <linux/err.h>
#include <linux/errno.h>
@@ -14,7 +14,7 @@ static inline struct socket *tap_get_socket(struct file *f)
{
return ERR_PTR(-EINVAL);
}
-static inline struct skb_array *tap_get_skb_array(struct file *f)
+static inline struct ptr_ring *tap_get_ptr_ring(struct file *f)
{
return ERR_PTR(-EINVAL);
}
@@ -70,7 +70,7 @@ struct tap_queue {
u16 queue_index;
bool enabled;
struct list_head next;
- struct skb_array skb_array;
+ struct ptr_ring ring;
};

rx_handler_result_t tap_handle_frame(struct sk_buff **pskb);
diff --git a/include/linux/if_tun.h b/include/linux/if_tun.h
index bf9bdf4..bdee9b8 100644
--- a/include/linux/if_tun.h
+++ b/include/linux/if_tun.h
@@ -19,7 +19,7 @@

#if defined(CONFIG_TUN) || defined(CONFIG_TUN_MODULE)
struct socket *tun_get_socket(struct file *);
-struct skb_array *tun_get_skb_array(struct file *file);
+struct ptr_ring *tun_get_tx_ring(struct file *file);
#else
#include <linux/err.h>
#include <linux/errno.h>
@@ -29,7 +29,7 @@ static inline struct socket *tun_get_socket(struct file *f)
{
return ERR_PTR(-EINVAL);
}
-static inline struct skb_array *tun_get_skb_array(struct file *f)
+static inline struct ptr_ring *tun_get_tx_ring(struct file *f)
{
return ERR_PTR(-EINVAL);
}
--
2.7.4