[RFC PATCH v3 10/20] io_uring: setup ZC for an Rx queue when registering an ifq

David Wei
2023-12-19T21:04:15Z

From: David Wei <davidhwei@meta.com>

This patch sets up ZC for an Rx queue in a net device when an ifq is
registered with io_uring. The Rx queue is specified in the registration
struct.

For now since there is only one ifq, its destruction is implicit during
io_uring cleanup.

Signed-off-by: David Wei <dw@davidwei.uk>
---
io_uring/zc_rx.c | 45 +++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 43 insertions(+), 2 deletions(-)

diff --git a/io_uring/zc_rx.c b/io_uring/zc_rx.c
index 7e3e6f6d446b..259e08a34ab2 100644
--- a/io_uring/zc_rx.c
+++ b/io_uring/zc_rx.c
@@ -4,6 +4,7 @@
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/io_uring.h>
+#include <linux/netdevice.h>

#include <uapi/linux/io_uring.h>

@@ -11,6 +12,34 @@
#include "kbuf.h"
#include "zc_rx.h"

+typedef int (*bpf_op_t)(struct net_device *dev, struct netdev_bpf *bpf);
+
+static int __io_queue_mgmt(struct net_device *dev, struct io_zc_rx_ifq *ifq,
+ u16 queue_id)
+{
+ struct netdev_bpf cmd;
+ bpf_op_t ndo_bpf;
+
+ ndo_bpf = dev->netdev_ops->ndo_bpf;
+ if (!ndo_bpf)
+ return -EINVAL;
+
+ cmd.command = XDP_SETUP_ZC_RX;
+ cmd.zc_rx.ifq = ifq;
+ cmd.zc_rx.queue_id = queue_id;
+ return ndo_bpf(dev, &cmd);
+}
+
+static int io_open_zc_rxq(struct io_zc_rx_ifq *ifq)
+{
+ return __io_queue_mgmt(ifq->dev, ifq, ifq->if_rxq_id);
+}
+
+static int io_close_zc_rxq(struct io_zc_rx_ifq *ifq)
+{
+ return __io_queue_mgmt(ifq->dev, NULL, ifq->if_rxq_id);
+}
+
static int io_allocate_rbuf_ring(struct io_zc_rx_ifq *ifq,
struct io_uring_zc_rx_ifq_reg *reg)
{
@@ -52,6 +81,10 @@ static struct io_zc_rx_ifq *io_zc_rx_ifq_alloc(struct io_ring_ctx *ctx)

static void io_zc_rx_ifq_free(struct io_zc_rx_ifq *ifq)
{
+ if (ifq->if_rxq_id != -1)
+ io_close_zc_rxq(ifq);
+ if (ifq->dev)
+ dev_put(ifq->dev);
io_free_rbuf_ring(ifq);
kfree(ifq);
}
@@ -77,18 +110,25 @@ int io_register_zc_rx_ifq(struct io_ring_ctx *ctx,
if (!ifq)
return -ENOMEM;

- /* TODO: initialise network interface */
-
ret = io_allocate_rbuf_ring(ifq, &reg);
if (ret)
goto err;

+ ret = -ENODEV;
+ ifq->dev = dev_get_by_index(current->nsproxy->net_ns, reg.if_idx);
+ if (!ifq->dev)
+ goto err;
+
/* TODO: map zc region and initialise zc pool */

ifq->rq_entries = reg.rq_entries;
ifq->cq_entries = reg.cq_entries;
ifq->if_rxq_id = reg.if_rxq_id;

+ ret = io_open_zc_rxq(ifq);
+ if (ret)
+ goto err;
+
ring_sz = sizeof(struct io_rbuf_ring);
rqes_sz = sizeof(struct io_uring_rbuf_rqe) * ifq->rq_entries;
cqes_sz = sizeof(struct io_uring_rbuf_cqe) * ifq->cq_entries;
@@ -101,6 +141,7 @@ int io_register_zc_rx_ifq(struct io_ring_ctx *ctx,
reg.cq_off.tail = offsetof(struct io_rbuf_ring, cq.tail);

if (copy_to_user(arg, &reg, sizeof(reg))) {
+ io_close_zc_rxq(ifq);
ret = -EFAULT;
goto err;
}
--
2.39.3