[PATCH net-next 1/2] net: page_pool: support dumping pps of a specific ifindex via Netlink

[Jakub Kicinski <kuba@kernel.org>]

NIPA tries to make sure that HW tests don't modify system state.
It saves the state of page pools, too. Now that I write this commit
message I realize that this is impractical since page pool IDs and
state will get legitimately changed by the tests. But I already
spent a couple of hours implementing the filtering, so..

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 Documentation/netlink/specs/netdev.yaml |  6 ++++
 net/core/netdev-genl-gen.c              | 30 ++++++++++++----
 net/core/page_pool_user.c               | 47 +++++++++++++++++++++++--
 3 files changed, 74 insertions(+), 9 deletions(-)

diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
index 596c306ce52b..f998cc64323c 100644
--- a/Documentation/netlink/specs/netdev.yaml
+++ b/Documentation/netlink/specs/netdev.yaml
@@ -620,6 +620,9 @@ doc: >-
             - dmabuf
             - io-uring
       dump:
+        request:
+          attributes:
+            - ifindex
         reply: *pp-reply
       config-cond: page-pool
     -
@@ -663,6 +666,9 @@ doc: >-
             - recycle-ring-full
             - recycle-released-refcnt
       dump:
+        request:
+          attributes:
+            - info
         reply: *pp-stats-reply
       config-cond: page-pool-stats
     -
diff --git a/net/core/netdev-genl-gen.c b/net/core/netdev-genl-gen.c
index ba673e81716f..22cbbdc40c6a 100644
--- a/net/core/netdev-genl-gen.c
+++ b/net/core/netdev-genl-gen.c
@@ -48,6 +48,11 @@ static const struct nla_policy netdev_dev_get_nl_policy[NETDEV_A_DEV_IFINDEX + 1
 static const struct nla_policy netdev_page_pool_get_nl_policy[NETDEV_A_PAGE_POOL_ID + 1] = {
 	[NETDEV_A_PAGE_POOL_ID] = NLA_POLICY_FULL_RANGE(NLA_UINT, &netdev_a_page_pool_id_range),
 };
+
+/* NETDEV_CMD_PAGE_POOL_GET - dump */
+static const struct nla_policy netdev_page_pool_get_dump_nl_policy[NETDEV_A_PAGE_POOL_IFINDEX + 1] = {
+	[NETDEV_A_PAGE_POOL_IFINDEX] = NLA_POLICY_FULL_RANGE(NLA_U32, &netdev_a_page_pool_ifindex_range),
+};
 #endif /* CONFIG_PAGE_POOL */
 
 /* NETDEV_CMD_PAGE_POOL_STATS_GET - do */
@@ -55,6 +60,15 @@ static const struct nla_policy netdev_page_pool_get_nl_policy[NETDEV_A_PAGE_POOL
 static const struct nla_policy netdev_page_pool_stats_get_nl_policy[NETDEV_A_PAGE_POOL_STATS_INFO + 1] = {
 	[NETDEV_A_PAGE_POOL_STATS_INFO] = NLA_POLICY_NESTED(netdev_page_pool_info_nl_policy),
 };
+
+/* NETDEV_CMD_PAGE_POOL_STATS_GET - dump */
+static const struct nla_policy netdev_page_pool_stats_get_dump_info_nl_policy[NETDEV_A_PAGE_POOL_IFINDEX + 1] = {
+	[NETDEV_A_PAGE_POOL_IFINDEX] = NLA_POLICY_FULL_RANGE(NLA_U32, &netdev_a_page_pool_ifindex_range),
+};
+
+static const struct nla_policy netdev_page_pool_stats_get_dump_nl_policy[NETDEV_A_PAGE_POOL_STATS_INFO + 1] = {
+	[NETDEV_A_PAGE_POOL_STATS_INFO] = NLA_POLICY_NESTED(netdev_page_pool_stats_get_dump_info_nl_policy),
+};
 #endif /* CONFIG_PAGE_POOL_STATS */
 
 /* NETDEV_CMD_QUEUE_GET - do */
@@ -130,9 +144,11 @@ static const struct genl_split_ops netdev_nl_ops[] = {
 		.flags		= GENL_CMD_CAP_DO,
 	},
 	{
-		.cmd	= NETDEV_CMD_PAGE_POOL_GET,
-		.dumpit	= netdev_nl_page_pool_get_dumpit,
-		.flags	= GENL_CMD_CAP_DUMP,
+		.cmd		= NETDEV_CMD_PAGE_POOL_GET,
+		.dumpit		= netdev_nl_page_pool_get_dumpit,
+		.policy		= netdev_page_pool_get_dump_nl_policy,
+		.maxattr	= NETDEV_A_PAGE_POOL_IFINDEX,
+		.flags		= GENL_CMD_CAP_DUMP,
 	},
 #endif /* CONFIG_PAGE_POOL */
 #ifdef CONFIG_PAGE_POOL_STATS
@@ -144,9 +160,11 @@ static const struct genl_split_ops netdev_nl_ops[] = {
 		.flags		= GENL_CMD_CAP_DO,
 	},
 	{
-		.cmd	= NETDEV_CMD_PAGE_POOL_STATS_GET,
-		.dumpit	= netdev_nl_page_pool_stats_get_dumpit,
-		.flags	= GENL_CMD_CAP_DUMP,
+		.cmd		= NETDEV_CMD_PAGE_POOL_STATS_GET,
+		.dumpit		= netdev_nl_page_pool_stats_get_dumpit,
+		.policy		= netdev_page_pool_stats_get_dump_nl_policy,
+		.maxattr	= NETDEV_A_PAGE_POOL_STATS_INFO,
+		.flags		= GENL_CMD_CAP_DUMP,
 	},
 #endif /* CONFIG_PAGE_POOL_STATS */
 	{
diff --git a/net/core/page_pool_user.c b/net/core/page_pool_user.c
index ee5060d8eec0..01509d1b3cba 100644
--- a/net/core/page_pool_user.c
+++ b/net/core/page_pool_user.c
@@ -79,7 +79,7 @@ struct page_pool_dump_cb {
 
 static int
 netdev_nl_page_pool_get_dump(struct sk_buff *skb, struct netlink_callback *cb,
-			     pp_nl_fill_cb fill)
+			     pp_nl_fill_cb fill, struct nlattr *ifindex_attr)
 {
 	struct page_pool_dump_cb *state = (void *)cb->ctx;
 	const struct genl_info *info = genl_info_dump(cb);
@@ -88,9 +88,17 @@ netdev_nl_page_pool_get_dump(struct sk_buff *skb, struct netlink_callback *cb,
 	struct page_pool *pool;
 	int err = 0;
 
+	if (ifindex_attr)
+		state->ifindex = nla_get_u32(ifindex_attr);
+
 	rtnl_lock();
 	mutex_lock(&page_pools_lock);
 	for_each_netdev_dump(net, netdev, state->ifindex) {
+		/* Either the provided ifindex doesn't exist or done dumping */
+		if (ifindex_attr &&
+		    netdev->ifindex != nla_get_u32(ifindex_attr))
+			break;
+
 		hlist_for_each_entry(pool, &netdev->page_pools, user.list) {
 			if (state->pp_id && state->pp_id < pool->user.id)
 				continue;
@@ -206,10 +214,40 @@ int netdev_nl_page_pool_stats_get_doit(struct sk_buff *skb,
 	return netdev_nl_page_pool_get_do(info, id, page_pool_nl_stats_fill);
 }
 
+static const struct netlink_range_validation page_pool_ifindex_range = {
+	.min	= 1ULL,
+	.max	= S32_MAX,
+};
+
+static const struct nla_policy
+page_pool_stat_info_policy[NETDEV_A_PAGE_POOL_IFINDEX + 1] = {
+	[NETDEV_A_PAGE_POOL_IFINDEX] =
+		NLA_POLICY_FULL_RANGE(NLA_U32, &page_pool_ifindex_range),
+};
+
 int netdev_nl_page_pool_stats_get_dumpit(struct sk_buff *skb,
 					 struct netlink_callback *cb)
 {
-	return netdev_nl_page_pool_get_dump(skb, cb, page_pool_nl_stats_fill);
+	struct nlattr *tb[ARRAY_SIZE(page_pool_stat_info_policy)];
+	const struct genl_info *info = genl_info_dump(cb);
+	struct nlattr *ifindex_attr = NULL;
+
+	if (info->attrs[NETDEV_A_PAGE_POOL_STATS_INFO]) {
+		struct nlattr *nest;
+		int err;
+
+		nest = info->attrs[NETDEV_A_PAGE_POOL_STATS_INFO];
+		err = nla_parse_nested(tb, ARRAY_SIZE(tb) - 1, nest,
+				       page_pool_stat_info_policy,
+				       info->extack);
+		if (err)
+			return err;
+
+		ifindex_attr = tb[NETDEV_A_PAGE_POOL_IFINDEX];
+	}
+
+	return netdev_nl_page_pool_get_dump(skb, cb, page_pool_nl_stats_fill,
+					    ifindex_attr);
 }
 
 static int
@@ -305,7 +343,10 @@ int netdev_nl_page_pool_get_doit(struct sk_buff *skb, struct genl_info *info)
 int netdev_nl_page_pool_get_dumpit(struct sk_buff *skb,
 				   struct netlink_callback *cb)
 {
-	return netdev_nl_page_pool_get_dump(skb, cb, page_pool_nl_fill);
+	const struct genl_info *info = genl_info_dump(cb);
+
+	return netdev_nl_page_pool_get_dump(skb, cb, page_pool_nl_fill,
+					    info->attrs[NETDEV_A_PAGE_POOL_IFINDEX]);
 }
 
 int page_pool_list(struct page_pool *pool)
-- 
2.53.0