[PATCH v1 03/15] io_uring: add register ifq opcode

Jonathan Lemon
2022-11-08T05:05:33Z

Add initial support for support for hooking in zero-copy interface
queues to io_uring. This command requests a user-managed queue
from the specified network device.

This only includes the register opcode, unregistration is currently
done implicitly when the ring is removed.

Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
---
include/uapi/linux/io_uring.h | 15 ++++
io_uring/Makefile | 3 +-
io_uring/io_uring.c | 8 ++
io_uring/zctap.c | 134 ++++++++++++++++++++++++++++++++++
io_uring/zctap.h | 9 +++
5 files changed, 168 insertions(+), 1 deletion(-)
create mode 100644 io_uring/zctap.c
create mode 100644 io_uring/zctap.h

diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index ab7458033ee3..f65543595d71 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -490,6 +490,9 @@ enum {
/* register a range of fixed file slots for automatic slot allocation */
IORING_REGISTER_FILE_ALLOC_RANGE = 25,

+ /* register a network ifq for zerocopy RX */
+ IORING_REGISTER_IFQ = 26,
+
/* this goes last */
IORING_REGISTER_LAST
};
@@ -666,6 +669,18 @@ struct io_uring_recvmsg_out {
__u32 flags;
};

+/*
+ * Argument for IORING_REGISTER_IFQ
+ */
+struct io_uring_ifq_req {
+ __u32 ifindex;
+ __u16 queue_id;
+ __u16 ifq_id;
+ __u16 fill_bgid;
+ __u16 region_id;
+ __u16 resv[2];
+};
+
#ifdef __cplusplus
}
#endif
diff --git a/io_uring/Makefile b/io_uring/Makefile
index 8cc8e5387a75..9d87e2e45ef9 100644
--- a/io_uring/Makefile
+++ b/io_uring/Makefile
@@ -7,5 +7,6 @@ obj-$(CONFIG_IO_URING) += io_uring.o xattr.o nop.o fs.o splice.o \
openclose.o uring_cmd.o epoll.o \
statx.o net.o msg_ring.o timeout.o \
sqpoll.o fdinfo.o tctx.o poll.o \
- cancel.o kbuf.o rsrc.o rw.o opdef.o notif.o
+ cancel.o kbuf.o rsrc.o rw.o opdef.o \
+ notif.o zctap.o
obj-$(CONFIG_IO_WQ) += io-wq.o
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index ac8c488e3077..0d67b0d05ef9 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -91,6 +91,7 @@
#include "cancel.h"
#include "net.h"
#include "notif.h"
+#include "zctap.h"

#include "timeout.h"
#include "poll.h"
@@ -2799,6 +2800,7 @@ static __cold void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
__io_cqring_overflow_flush(ctx, true);
xa_for_each(&ctx->personalities, index, creds)
io_unregister_personality(ctx, index);
+ io_unregister_zctap_all(ctx);
if (ctx->rings)
io_poll_remove_all(ctx, NULL, true);
mutex_unlock(&ctx->uring_lock);
@@ -4031,6 +4033,12 @@ static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
break;
ret = io_register_file_alloc_range(ctx, arg);
break;
+ case IORING_REGISTER_IFQ:
+ ret = -EINVAL;
+ if (!arg || nr_args != 1)
+ break;
+ ret = io_register_ifq(ctx, arg);
+ break;
default:
ret = -EINVAL;
break;
diff --git a/io_uring/zctap.c b/io_uring/zctap.c
new file mode 100644
index 000000000000..2ba05110ea8a
--- /dev/null
+++ b/io_uring/zctap.c
@@ -0,0 +1,134 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/file.h>
+#include <linux/mm.h>
+#include <linux/io_uring.h>
+#include <linux/netdevice.h>
+
+#include <uapi/linux/io_uring.h>
+
+#include "io_uring.h"
+#include "zctap.h"
+
+#define NR_ZCTAP_IFQS 1
+
+typedef int (*bpf_op_t)(struct net_device *dev, struct netdev_bpf *bpf);
+
+static int __io_queue_mgmt(struct net_device *dev, struct io_zctap_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_ZCTAP;
+ cmd.zct.ifq = ifq;
+ cmd.zct.queue_id = queue_id;
+
+ return ndo_bpf(dev, &cmd);
+}
+
+static int io_open_zctap_ifq(struct io_zctap_ifq *ifq, u16 queue_id)
+{
+ return __io_queue_mgmt(ifq->dev, ifq, queue_id);
+}
+
+static int io_close_zctap_ifq(struct io_zctap_ifq *ifq, u16 queue_id)
+{
+ return __io_queue_mgmt(ifq->dev, NULL, queue_id);
+}
+
+static struct io_zctap_ifq *io_zctap_ifq_alloc(struct io_ring_ctx *ctx)
+{
+ struct io_zctap_ifq *ifq;
+
+ ifq = kzalloc(sizeof(*ifq), GFP_KERNEL);
+ if (!ifq)
+ return NULL;
+
+ ifq->ctx = ctx;
+ ifq->queue_id = -1;
+ return ifq;
+}
+
+static void io_zctap_ifq_free(struct io_zctap_ifq *ifq)
+{
+ if (ifq->queue_id != -1)
+ io_close_zctap_ifq(ifq, ifq->queue_id);
+ if (ifq->dev)
+ dev_put(ifq->dev);
+ kfree(ifq);
+}
+
+int io_register_ifq(struct io_ring_ctx *ctx,
+ struct io_uring_ifq_req __user *arg)
+{
+ struct io_uring_ifq_req req;
+ struct io_zctap_ifq *ifq;
+ int err;
+
+ if (copy_from_user(&req, arg, sizeof(req)))
+ return -EFAULT;
+
+ if (req.resv[0] || req.resv[1])
+ return -EINVAL;
+
+ if (req.ifq_id >= NR_ZCTAP_IFQS)
+ return -EINVAL;
+
+ if (ctx->zctap_ifq)
+ return -EBUSY;
+
+ ifq = io_zctap_ifq_alloc(ctx);
+ if (!ifq)
+ return -ENOMEM;
+
+ ifq->fill_bgid = req.fill_bgid;
+
+ err = -ENODEV;
+ ifq->dev = dev_get_by_index(&init_net, req.ifindex);
+ if (!ifq->dev)
+ goto out;
+
+ /* region attachment TBD */
+
+ err = io_open_zctap_ifq(ifq, req.queue_id);
+ if (err)
+ goto out;
+ ifq->queue_id = req.queue_id;
+
+ ctx->zctap_ifq = ifq;
+
+ return 0;
+
+out:
+ io_zctap_ifq_free(ifq);
+ return err;
+}
+
+int io_unregister_zctap_ifq(struct io_ring_ctx *ctx, unsigned long index)
+{
+ struct io_zctap_ifq *ifq;
+
+ ifq = ctx->zctap_ifq;
+ if (!ifq)
+ return -EINVAL;
+
+ ctx->zctap_ifq = NULL;
+ io_zctap_ifq_free(ifq);
+
+ return 0;
+}
+
+void io_unregister_zctap_all(struct io_ring_ctx *ctx)
+{
+ int i;
+
+ for (i = 0; i < NR_ZCTAP_IFQS; i++)
+ io_unregister_zctap_ifq(ctx, i);
+}
diff --git a/io_uring/zctap.h b/io_uring/zctap.h
new file mode 100644
index 000000000000..bbe4a509408b
--- /dev/null
+++ b/io_uring/zctap.h
@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef IOU_ZCTAP_H
+#define IOU_ZCTAP_H
+
+int io_register_ifq(struct io_ring_ctx *ctx,
+ struct io_uring_ifq_req __user *arg);
+void io_unregister_zctap_all(struct io_ring_ctx *ctx);
+
+#endif
--
2.30.2