xsk: add Rx receive functions and poll support

Here the actual receive functions of AF_XDP are implemented, that in a
later commit, will be called from the XDP layers.

There's one set of functions for the XDP_DRV side and another for
XDP_SKB (generic).

A new XDP API, xdp_return_buff, is also introduced.

Adding xdp_return_buff, which is analogous to xdp_return_frame, but
acts upon an struct xdp_buff. The API will be used by AF_XDP in future
commits.

Support for the poll syscall is also implemented.

v2: xskq_validate_id did not update cons_tail.
    The entries variable was calculated twice in xskq_nb_avail.
    Squashed xdp_return_buff commit.

Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Björn Töpel 2018-05-02 13:01:27 +02:00 committed by Alexei Starovoitov
parent 965a990984
commit c497176cb2
6 changed files with 238 additions and 5 deletions

View File

@ -104,6 +104,7 @@ struct xdp_frame *convert_to_xdp_frame(struct xdp_buff *xdp)
}
void xdp_return_frame(struct xdp_frame *xdpf);
void xdp_return_buff(struct xdp_buff *xdp);
int xdp_rxq_info_reg(struct xdp_rxq_info *xdp_rxq,
struct net_device *dev, u32 queue_index);

View File

@ -31,6 +31,28 @@ struct xdp_sock {
u16 queue_id;
/* Protects multiple processes in the control path */
struct mutex mutex;
u64 rx_dropped;
};
struct xdp_buff;
#ifdef CONFIG_XDP_SOCKETS
int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp);
int xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp);
void xsk_flush(struct xdp_sock *xs);
#else
static inline int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
{
return -ENOTSUPP;
}
static inline int xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
{
return -ENOTSUPP;
}
static inline void xsk_flush(struct xdp_sock *xs)
{
}
#endif /* CONFIG_XDP_SOCKETS */
#endif /* _LINUX_XDP_SOCK_H */

View File

@ -308,11 +308,9 @@ int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq,
}
EXPORT_SYMBOL_GPL(xdp_rxq_info_reg_mem_model);
void xdp_return_frame(struct xdp_frame *xdpf)
static void xdp_return(void *data, struct xdp_mem_info *mem)
{
struct xdp_mem_info *mem = &xdpf->mem;
struct xdp_mem_allocator *xa;
void *data = xdpf->data;
struct page *page;
switch (mem->type) {
@ -339,4 +337,15 @@ void xdp_return_frame(struct xdp_frame *xdpf)
break;
}
}
void xdp_return_frame(struct xdp_frame *xdpf)
{
xdp_return(xdpf->data, &xdpf->mem);
}
EXPORT_SYMBOL_GPL(xdp_return_frame);
void xdp_return_buff(struct xdp_buff *xdp)
{
xdp_return(xdp->data, &xdp->rxq->mem);
}
EXPORT_SYMBOL_GPL(xdp_return_buff);

View File

@ -39,6 +39,24 @@ struct xdp_umem {
struct work_struct work;
};
static inline char *xdp_umem_get_data(struct xdp_umem *umem, u32 idx)
{
u64 pg, off;
char *data;
pg = idx >> umem->nfpplog2;
off = (idx & umem->nfpp_mask) << umem->frame_size_log2;
data = page_address(umem->pgs[pg]);
return data + off;
}
static inline char *xdp_umem_get_data_with_headroom(struct xdp_umem *umem,
u32 idx)
{
return xdp_umem_get_data(umem, idx) + umem->frame_headroom;
}
bool xdp_umem_validate_queues(struct xdp_umem *umem);
int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr);
void xdp_get_umem(struct xdp_umem *umem);

View File

@ -41,6 +41,74 @@ static struct xdp_sock *xdp_sk(struct sock *sk)
return (struct xdp_sock *)sk;
}
static int __xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
{
u32 *id, len = xdp->data_end - xdp->data;
void *buffer;
int err = 0;
if (xs->dev != xdp->rxq->dev || xs->queue_id != xdp->rxq->queue_index)
return -EINVAL;
id = xskq_peek_id(xs->umem->fq);
if (!id)
return -ENOSPC;
buffer = xdp_umem_get_data_with_headroom(xs->umem, *id);
memcpy(buffer, xdp->data, len);
err = xskq_produce_batch_desc(xs->rx, *id, len,
xs->umem->frame_headroom);
if (!err)
xskq_discard_id(xs->umem->fq);
return err;
}
int xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
{
int err;
err = __xsk_rcv(xs, xdp);
if (likely(!err))
xdp_return_buff(xdp);
else
xs->rx_dropped++;
return err;
}
void xsk_flush(struct xdp_sock *xs)
{
xskq_produce_flush_desc(xs->rx);
xs->sk.sk_data_ready(&xs->sk);
}
int xsk_generic_rcv(struct xdp_sock *xs, struct xdp_buff *xdp)
{
int err;
err = __xsk_rcv(xs, xdp);
if (!err)
xsk_flush(xs);
else
xs->rx_dropped++;
return err;
}
static unsigned int xsk_poll(struct file *file, struct socket *sock,
struct poll_table_struct *wait)
{
unsigned int mask = datagram_poll(file, sock, wait);
struct sock *sk = sock->sk;
struct xdp_sock *xs = xdp_sk(sk);
if (xs->rx && !xskq_empty_desc(xs->rx))
mask |= POLLIN | POLLRDNORM;
return mask;
}
static int xsk_init_queue(u32 entries, struct xsk_queue **queue,
bool umem_queue)
{
@ -179,6 +247,9 @@ static int xsk_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
} else if (!xs->umem || !xdp_umem_validate_queues(xs->umem)) {
err = -EINVAL;
goto out_unlock;
} else {
/* This xsk has its own umem. */
xskq_set_umem(xs->umem->fq, &xs->umem->props);
}
/* Rebind? */
@ -330,7 +401,7 @@ static const struct proto_ops xsk_proto_ops = {
.socketpair = sock_no_socketpair,
.accept = sock_no_accept,
.getname = sock_no_getname,
.poll = sock_no_poll,
.poll = xsk_poll,
.ioctl = sock_no_ioctl,
.listen = sock_no_listen,
.shutdown = sock_no_shutdown,

View File

@ -20,6 +20,8 @@
#include "xdp_umem_props.h"
#define RX_BATCH_SIZE 16
struct xsk_queue {
struct xdp_umem_props umem_props;
u32 ring_mask;
@ -32,8 +34,118 @@ struct xsk_queue {
u64 invalid_descs;
};
/* Common functions operating for both RXTX and umem queues */
static inline u32 xskq_nb_avail(struct xsk_queue *q, u32 dcnt)
{
u32 entries = q->prod_tail - q->cons_tail;
if (entries == 0) {
/* Refresh the local pointer */
q->prod_tail = READ_ONCE(q->ring->producer);
entries = q->prod_tail - q->cons_tail;
}
return (entries > dcnt) ? dcnt : entries;
}
static inline u32 xskq_nb_free(struct xsk_queue *q, u32 producer, u32 dcnt)
{
u32 free_entries = q->nentries - (producer - q->cons_tail);
if (free_entries >= dcnt)
return free_entries;
/* Refresh the local tail pointer */
q->cons_tail = READ_ONCE(q->ring->consumer);
return q->nentries - (producer - q->cons_tail);
}
/* UMEM queue */
static inline bool xskq_is_valid_id(struct xsk_queue *q, u32 idx)
{
if (unlikely(idx >= q->umem_props.nframes)) {
q->invalid_descs++;
return false;
}
return true;
}
static inline u32 *xskq_validate_id(struct xsk_queue *q)
{
while (q->cons_tail != q->cons_head) {
struct xdp_umem_ring *ring = (struct xdp_umem_ring *)q->ring;
unsigned int idx = q->cons_tail & q->ring_mask;
if (xskq_is_valid_id(q, ring->desc[idx]))
return &ring->desc[idx];
q->cons_tail++;
}
return NULL;
}
static inline u32 *xskq_peek_id(struct xsk_queue *q)
{
struct xdp_umem_ring *ring;
if (q->cons_tail == q->cons_head) {
WRITE_ONCE(q->ring->consumer, q->cons_tail);
q->cons_head = q->cons_tail + xskq_nb_avail(q, RX_BATCH_SIZE);
/* Order consumer and data */
smp_rmb();
return xskq_validate_id(q);
}
ring = (struct xdp_umem_ring *)q->ring;
return &ring->desc[q->cons_tail & q->ring_mask];
}
static inline void xskq_discard_id(struct xsk_queue *q)
{
q->cons_tail++;
(void)xskq_validate_id(q);
}
/* Rx queue */
static inline int xskq_produce_batch_desc(struct xsk_queue *q,
u32 id, u32 len, u16 offset)
{
struct xdp_rxtx_ring *ring = (struct xdp_rxtx_ring *)q->ring;
unsigned int idx;
if (xskq_nb_free(q, q->prod_head, 1) == 0)
return -ENOSPC;
idx = (q->prod_head++) & q->ring_mask;
ring->desc[idx].idx = id;
ring->desc[idx].len = len;
ring->desc[idx].offset = offset;
return 0;
}
static inline void xskq_produce_flush_desc(struct xsk_queue *q)
{
/* Order producer and data */
smp_wmb();
q->prod_tail = q->prod_head,
WRITE_ONCE(q->ring->producer, q->prod_tail);
}
static inline bool xskq_empty_desc(struct xsk_queue *q)
{
return (xskq_nb_free(q, q->prod_tail, 1) == q->nentries);
}
void xskq_set_umem(struct xsk_queue *q, struct xdp_umem_props *umem_props);
struct xsk_queue *xskq_create(u32 nentries, bool umem_queue);
void xskq_destroy(struct xsk_queue *q);
void xskq_destroy(struct xsk_queue *q_ops);
#endif /* _LINUX_XSK_QUEUE_H */