[PATCH net-next v2 1/2] netdev-genl: Add an XSK attribute to queues

[Joe Damato <jdamato@fastly.com>]

Expose a new per-queue nest attribute, xsk, which will be present for
queues that are being used for AF_XDP. If the queue is not being used for
AF_XDP, the nest will not be present.

In the future, this attribute can be extended to include more data about
XSK as it is needed.

Signed-off-by: Joe Damato <jdamato@fastly.com>
Suggested-by: Jakub Kicinski <kuba@kernel.org>
---
 v2:
   - Patch adjusted to include an attribute, xsk, which is an empty nest
     and exposed for queues which have a pool.

 Documentation/netlink/specs/netdev.yaml | 13 ++++++++++++-
 include/uapi/linux/netdev.h             |  6 ++++++
 net/core/netdev-genl.c                  | 11 +++++++++++
 tools/include/uapi/linux/netdev.h       |  6 ++++++
 4 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
index cbb544bd6c84..4c3eda5ba754 100644
--- a/Documentation/netlink/specs/netdev.yaml
+++ b/Documentation/netlink/specs/netdev.yaml
@@ -268,6 +268,9 @@ attribute-sets:
         doc: The timeout, in nanoseconds, of how long to suspend irq
              processing, if event polling finds events
         type: uint
+  -
+    name: xsk-info
+    attributes: []
   -
     name: queue
     attributes:
@@ -286,6 +289,9 @@ attribute-sets:
       -
         name: type
         doc: Queue type as rx, tx. Each queue type defines a separate ID space.
+             XDP TX queues allocated in the kernel are not linked to NAPIs and
+             thus not listed. AF_XDP queues will have more information set in
+             the xsk attribute.
         type: u32
         enum: queue-type
       -
@@ -296,7 +302,11 @@ attribute-sets:
         name: dmabuf
         doc: ID of the dmabuf attached to this queue, if any.
         type: u32
-
+      -
+        name: xsk
+        doc: XSK information for this queue, if any.
+        type: nest
+        nested-attributes: xsk-info
   -
     name: qstats
     doc: |
@@ -637,6 +647,7 @@ operations:
             - napi-id
             - ifindex
             - dmabuf
+            - xsk
       dump:
         request:
           attributes:
diff --git a/include/uapi/linux/netdev.h b/include/uapi/linux/netdev.h
index e4be227d3ad6..46bdb0b67a39 100644
--- a/include/uapi/linux/netdev.h
+++ b/include/uapi/linux/netdev.h
@@ -130,12 +130,18 @@ enum {
 	NETDEV_A_NAPI_MAX = (__NETDEV_A_NAPI_MAX - 1)
 };
 
+enum {
+	__NETDEV_A_XSK_INFO_MAX,
+	NETDEV_A_XSK_INFO_MAX = (__NETDEV_A_XSK_INFO_MAX - 1)
+};
+
 enum {
 	NETDEV_A_QUEUE_ID = 1,
 	NETDEV_A_QUEUE_IFINDEX,
 	NETDEV_A_QUEUE_TYPE,
 	NETDEV_A_QUEUE_NAPI_ID,
 	NETDEV_A_QUEUE_DMABUF,
+	NETDEV_A_QUEUE_XSK,
 
 	__NETDEV_A_QUEUE_MAX,
 	NETDEV_A_QUEUE_MAX = (__NETDEV_A_QUEUE_MAX - 1)
diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index 715f85c6b62e..efaccfb6438e 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -371,6 +371,7 @@ netdev_nl_queue_fill_one(struct sk_buff *rsp, struct net_device *netdev,
 	struct net_devmem_dmabuf_binding *binding;
 	struct netdev_rx_queue *rxq;
 	struct netdev_queue *txq;
+	struct nlattr *nest;
 	void *hdr;
 
 	hdr = genlmsg_iput(rsp, info);
@@ -394,12 +395,22 @@ netdev_nl_queue_fill_one(struct sk_buff *rsp, struct net_device *netdev,
 		    nla_put_u32(rsp, NETDEV_A_QUEUE_DMABUF, binding->id))
 			goto nla_put_failure;
 
+		if (rxq->pool) {
+			nest = nla_nest_start(rsp, NETDEV_A_QUEUE_XSK);
+			nla_nest_end(rsp, nest);
+		}
+
 		break;
 	case NETDEV_QUEUE_TYPE_TX:
 		txq = netdev_get_tx_queue(netdev, q_idx);
 		if (txq->napi && nla_put_u32(rsp, NETDEV_A_QUEUE_NAPI_ID,
 					     txq->napi->napi_id))
 			goto nla_put_failure;
+
+		if (txq->pool) {
+			nest = nla_nest_start(rsp, NETDEV_A_QUEUE_XSK);
+			nla_nest_end(rsp, nest);
+		}
 	}
 
 	genlmsg_end(rsp, hdr);
diff --git a/tools/include/uapi/linux/netdev.h b/tools/include/uapi/linux/netdev.h
index e4be227d3ad6..46bdb0b67a39 100644
--- a/tools/include/uapi/linux/netdev.h
+++ b/tools/include/uapi/linux/netdev.h
@@ -130,12 +130,18 @@ enum {
 	NETDEV_A_NAPI_MAX = (__NETDEV_A_NAPI_MAX - 1)
 };
 
+enum {
+	__NETDEV_A_XSK_INFO_MAX,
+	NETDEV_A_XSK_INFO_MAX = (__NETDEV_A_XSK_INFO_MAX - 1)
+};
+
 enum {
 	NETDEV_A_QUEUE_ID = 1,
 	NETDEV_A_QUEUE_IFINDEX,
 	NETDEV_A_QUEUE_TYPE,
 	NETDEV_A_QUEUE_NAPI_ID,
 	NETDEV_A_QUEUE_DMABUF,
+	NETDEV_A_QUEUE_XSK,
 
 	__NETDEV_A_QUEUE_MAX,
 	NETDEV_A_QUEUE_MAX = (__NETDEV_A_QUEUE_MAX - 1)
-- 
2.25.1