[PATCH RFC net-next 1/4] net: core: page_pool_user: Allow flexibility of 'ifindex' value

[Amit Cohen <amcohen@nvidia.com>]

Netlink message of page pool query includes 'ifindex'. Currently, this
value is always set to 'pool->slow.netdev->ifindex'. This allows getting
responses only for page pools which holds pointer to real netdevice.

In case that driver does not have 1:1 mapping between page pool and
netdevice, 'pool->slow.netdev->ifindex' will not point to netdevice. That
means that such drivers cannot query page pools info and statistics.

The functions page_pool_nl_stats_fill()/page_pool_nl_fill() get page
pool structure and use 'ifindex' which is stored in the pool to fill
netlink message. Instead, let the callers decide which 'ifindex' should
be used. For now, all the callers pass 'pool->slow.netdev->ifindex', so
there is no behavior change. The next patch will change dump behavior.

Signed-off-by: Amit Cohen <amcohen@nvidia.com>
---
 net/core/page_pool_user.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/net/core/page_pool_user.c b/net/core/page_pool_user.c
index 3a3277ba167b..44948f7b9d68 100644
--- a/net/core/page_pool_user.c
+++ b/net/core/page_pool_user.c
@@ -30,7 +30,7 @@ static DEFINE_MUTEX(page_pools_lock);
  */
 
 typedef int (*pp_nl_fill_cb)(struct sk_buff *rsp, const struct page_pool *pool,
-			     const struct genl_info *info);
+			     const struct genl_info *info, int ifindex);
 
 static int
 netdev_nl_page_pool_get_do(struct genl_info *info, u32 id, pp_nl_fill_cb fill)
@@ -53,7 +53,7 @@ netdev_nl_page_pool_get_do(struct genl_info *info, u32 id, pp_nl_fill_cb fill)
 		goto err_unlock;
 	}
 
-	err = fill(rsp, pool, info);
+	err = fill(rsp, pool, info, pool->slow.netdev->ifindex);
 	if (err)
 		goto err_free_msg;
 
@@ -92,7 +92,7 @@ netdev_nl_page_pool_get_dump(struct sk_buff *skb, struct netlink_callback *cb,
 				continue;
 
 			state->pp_id = pool->user.id;
-			err = fill(skb, pool, info);
+			err = fill(skb, pool, info, pool->slow.netdev->ifindex);
 			if (err)
 				goto out;
 		}
@@ -108,7 +108,7 @@ netdev_nl_page_pool_get_dump(struct sk_buff *skb, struct netlink_callback *cb,
 
 static int
 page_pool_nl_stats_fill(struct sk_buff *rsp, const struct page_pool *pool,
-			const struct genl_info *info)
+			const struct genl_info *info, int ifindex)
 {
 #ifdef CONFIG_PAGE_POOL_STATS
 	struct page_pool_stats stats = {};
@@ -125,9 +125,8 @@ page_pool_nl_stats_fill(struct sk_buff *rsp, const struct page_pool *pool,
 	nest = nla_nest_start(rsp, NETDEV_A_PAGE_POOL_STATS_INFO);
 
 	if (nla_put_uint(rsp, NETDEV_A_PAGE_POOL_ID, pool->user.id) ||
-	    (pool->slow.netdev->ifindex != LOOPBACK_IFINDEX &&
-	     nla_put_u32(rsp, NETDEV_A_PAGE_POOL_IFINDEX,
-			 pool->slow.netdev->ifindex)))
+	    (ifindex != LOOPBACK_IFINDEX &&
+	     nla_put_u32(rsp, NETDEV_A_PAGE_POOL_IFINDEX, ifindex)))
 		goto err_cancel_nest;
 
 	nla_nest_end(rsp, nest);
@@ -210,7 +209,7 @@ int netdev_nl_page_pool_stats_get_dumpit(struct sk_buff *skb,
 
 static int
 page_pool_nl_fill(struct sk_buff *rsp, const struct page_pool *pool,
-		  const struct genl_info *info)
+		  const struct genl_info *info, int ifindex)
 {
 	size_t inflight, refsz;
 	void *hdr;
@@ -222,9 +221,8 @@ page_pool_nl_fill(struct sk_buff *rsp, const struct page_pool *pool,
 	if (nla_put_uint(rsp, NETDEV_A_PAGE_POOL_ID, pool->user.id))
 		goto err_cancel;
 
-	if (pool->slow.netdev->ifindex != LOOPBACK_IFINDEX &&
-	    nla_put_u32(rsp, NETDEV_A_PAGE_POOL_IFINDEX,
-			pool->slow.netdev->ifindex))
+	if (ifindex != LOOPBACK_IFINDEX &&
+	    nla_put_u32(rsp, NETDEV_A_PAGE_POOL_IFINDEX, ifindex))
 		goto err_cancel;
 	if (pool->user.napi_id &&
 	    nla_put_uint(rsp, NETDEV_A_PAGE_POOL_NAPI_ID, pool->user.napi_id))
@@ -271,7 +269,7 @@ static void netdev_nl_page_pool_event(const struct page_pool *pool, u32 cmd)
 	if (!ntf)
 		return;
 
-	if (page_pool_nl_fill(ntf, pool, &info)) {
+	if (page_pool_nl_fill(ntf, pool, &info, pool->slow.netdev->ifindex)) {
 		nlmsg_free(ntf);
 		return;
 	}
-- 
2.45.1