[PATCH net-next v1 1/6] netmem: rename __get/__put_netmem() to get/put_net_iov()

[Mina Almasry]

netmems carry both a non-pp backing refcount and a page_pool
pp_ref_count. Make the non-pp layer explicit and symmetric across both
netmem types: get/put_netmem() dispatches to get/put_page() for pages
and get/put_net_iov() for net_iovs, always acquiring or releasing a
non-pp reference regardless of page_pool membership.

Warn via DEBUG_NET_WARN_ON_ONCE() for net_iov types that do not support
non-pp references.

Signed-off-by: Mina Almasry <almasrymina@xxxxxxxxxx>
---
 include/net/netmem.h | 24 ++++++++++++++++++++----
 net/core/skbuff.c    | 36 ++++++++++++++++++++++++++----------
 2 files changed, 46 insertions(+), 14 deletions(-)

diff --git a/include/net/netmem.h b/include/net/netmem.h
index 0cc8572f62caf..697d50c51a5ee 100644
--- a/include/net/netmem.h
+++ b/include/net/netmem.h
@@ -399,21 +399,37 @@ static inline bool net_is_devmem_iov(const struct net_iov *niov)
 }
 #endif
 
-void __get_netmem(netmem_ref netmem);
-void __put_netmem(netmem_ref netmem);
+void get_net_iov(struct net_iov *niov);
+void put_net_iov(struct net_iov *niov);
 
+/**
+ * get_netmem - acquire a non-page_pool reference on a netmem
+ * @netmem: netmem to reference
+ *
+ * Acquires a non-pp backing reference (page._refcount via get_page() or
+ * binding->ref via get_net_iov()) regardless of page_pool membership.
+ * Counterpart to put_netmem().
+ */
 static __always_inline void get_netmem(netmem_ref netmem)
 {
 	if (netmem_is_net_iov(netmem))
-		__get_netmem(netmem);
+		get_net_iov(netmem_to_net_iov(netmem));
 	else
 		get_page(netmem_to_page(netmem));
 }
 
+/**
+ * put_netmem - release a non-page_pool reference on a netmem
+ * @netmem: netmem to unreference
+ *
+ * Drops a non-pp backing reference (page._refcount via put_page() or
+ * binding->ref via put_net_iov()) regardless of page_pool membership.
+ * Counterpart to get_netmem().
+ */
 static __always_inline void put_netmem(netmem_ref netmem)
 {
 	if (netmem_is_net_iov(netmem))
-		__put_netmem(netmem);
+		put_net_iov(netmem_to_net_iov(netmem));
 	else
 		put_page(netmem_to_page(netmem));
 }
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index d56f4f0102f75..b459264ba5180 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -7551,23 +7551,39 @@ bool csum_and_copy_from_iter_full(void *addr, size_t bytes,
 }
 EXPORT_SYMBOL(csum_and_copy_from_iter_full);
 
-void __get_netmem(netmem_ref netmem)
+/**
+ * get_net_iov - acquire a non-page_pool reference on a net_iov
+ * @niov: net_iov to reference
+ *
+ * Acquires a non-pp backing reference (binding->ref) on @niov regardless of
+ * page_pool membership, warning if @niov does not support non-pp references.
+ * Counterpart to put_net_iov().
+ */
+void get_net_iov(struct net_iov *niov)
 {
-	struct net_iov *niov = netmem_to_net_iov(netmem);
-
 	if (net_is_devmem_iov(niov))
-		net_devmem_get_net_iov(netmem_to_net_iov(netmem));
+		net_devmem_get_net_iov(niov);
+	else
+		DEBUG_NET_WARN_ON_ONCE(true);
 }
-EXPORT_SYMBOL(__get_netmem);
+EXPORT_SYMBOL(get_net_iov);
 
-void __put_netmem(netmem_ref netmem)
+/**
+ * put_net_iov - release a non-page_pool reference on a net_iov
+ * @niov: net_iov to unreference
+ *
+ * Drops a non-pp backing reference (binding->ref) on @niov regardless of
+ * page_pool membership, warning if @niov does not support non-pp references.
+ * Counterpart to get_net_iov().
+ */
+void put_net_iov(struct net_iov *niov)
 {
-	struct net_iov *niov = netmem_to_net_iov(netmem);
-
 	if (net_is_devmem_iov(niov))
-		net_devmem_put_net_iov(netmem_to_net_iov(netmem));
+		net_devmem_put_net_iov(niov);
+	else
+		DEBUG_NET_WARN_ON_ONCE(true);
 }
-EXPORT_SYMBOL(__put_netmem);
+EXPORT_SYMBOL(put_net_iov);
 
 struct vlan_type_depth __vlan_get_protocol_offset(const struct sk_buff *skb,
 						  __be16 type,
-- 
2.56.0.385.gd3acb90ef8-goog