[RFC net-next 06/13] net: page_pool: stash the NAPI ID for easier access

[Jakub Kicinski <kuba@kernel.org>]

To avoid any issues with race conditions on accessing napi
and having to think about the lifetime of NAPI objects
in netlink GET - stash the napi_id to which page pool
was linked at creation time.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 include/net/page_pool/types.h | 1 +
 net/core/page_pool_user.c     | 4 +++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/net/page_pool/types.h b/include/net/page_pool/types.h
index b9db612708e4..3017557e0c59 100644
--- a/include/net/page_pool/types.h
+++ b/include/net/page_pool/types.h
@@ -195,6 +195,7 @@ struct page_pool {
 	/* User-facing fields, protected by page_pools_lock */
 	struct {
 		struct hlist_node list;
+		u32 napi_id;
 		u32 id;
 	} user;
 };
diff --git a/net/core/page_pool_user.c b/net/core/page_pool_user.c
index 25977ce18e2b..6632fc19a86f 100644
--- a/net/core/page_pool_user.c
+++ b/net/core/page_pool_user.c
@@ -37,9 +37,11 @@ int page_pool_list(struct page_pool *pool)
 	if (err < 0)
 		goto err_unlock;
 
-	if (pool->slow.netdev)
+	if (pool->slow.netdev) {
 		hlist_add_head(&pool->user.list,
 			       &pool->slow.netdev->page_pools);
+		pool->user.napi_id = pool->p.napi ? pool->p.napi->napi_id : 0;
+	}
 
 	mutex_unlock(&page_pools_lock);
 	return 0;
-- 
2.41.0