netdev - [PATCH net-next 3/4] net: inline net_is_devmem

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Message-ID: <20260122045720.1221017-4-edumazet@google.com>
Date: Thu, 22 Jan 2026 04:57:18 +0000
From: Eric Dumazet <edumazet@...gle.com>
To: "David S . Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>, 
	Paolo Abeni <pabeni@...hat.com>
Cc: Simon Horman <horms@...nel.org>, netdev@...r.kernel.org, eric.dumazet@...il.com, 
	Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH net-next 3/4] net: inline net_is_devmem_iov()

1) Inline this small helper to reduce code size and decrease cpu costs.
2) Constify its argument.
3) Move it to include/net/netmem.h, as a prereq for the following patch.

$ scripts/bloat-o-meter -t vmlinux.2 vmlinux.3
add/remove: 0/2 grow/shrink: 0/4 up/down: 0/-158 (-158)
Function                                     old     new   delta
validate_xmit_skb                            866     857      -9
__pfx_net_is_devmem_iov                       16       -     -16
net_is_devmem_iov                             22       -     -22
get_netmem                                   152     130     -22
put_netmem                                   140     114     -26
tcp_recvmsg_locked                          3860    3797     -63
Total: Before=22566015, After=22565857, chg -0.00%

Signed-off-by: Eric Dumazet <edumazet@...gle.com>
---
 include/net/netmem.h | 12 ++++++++++++
 net/core/devmem.c    |  5 -----
 net/core/devmem.h    |  7 +------
 3 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/include/net/netmem.h b/include/net/netmem.h
index 9e10f4ac50c3d4381d2404c3b079366dfc08bab7..2113a197abb315f608ee3d6d3e8a60811b3781f8 100644
--- a/include/net/netmem.h
+++ b/include/net/netmem.h
@@ -389,6 +389,18 @@ static inline unsigned long netmem_get_dma_addr(netmem_ref netmem)
 	return netmem_to_nmdesc(netmem)->dma_addr;
 }
 
+#if defined(CONFIG_NET_DEVMEM)
+static inline bool net_is_devmem_iov(const struct net_iov *niov)
+{
+	return niov->type == NET_IOV_DMABUF;
+}
+#else
+static inline bool net_is_devmem_iov(const struct net_iov *niov)
+{
+	return false;
+}
+#endif
+
 void get_netmem(netmem_ref netmem);
 void put_netmem(netmem_ref netmem);
 
diff --git a/net/core/devmem.c b/net/core/devmem.c
index 185ed2a73d1cfa55858e4e0d42be365f612662fa..63f093f7d2b23f01929b83746ae25779d3f925d0 100644
--- a/net/core/devmem.c
+++ b/net/core/devmem.c
@@ -30,11 +30,6 @@ static DEFINE_XARRAY_FLAGS(net_devmem_dmabuf_bindings, XA_FLAGS_ALLOC1);
 
 static const struct memory_provider_ops dmabuf_devmem_ops;
 
-bool net_is_devmem_iov(struct net_iov *niov)
-{
-	return niov->type == NET_IOV_DMABUF;
-}
-
 static void net_devmem_dmabuf_free_chunk_owner(struct gen_pool *genpool,
 					       struct gen_pool_chunk *chunk,
 					       void *not_used)
diff --git a/net/core/devmem.h b/net/core/devmem.h
index 2534c8144212c79f09389201ae190511948977fb..1c5c18581fcb146450cfb18a4b1d0ce8a17b96a9 100644
--- a/net/core/devmem.h
+++ b/net/core/devmem.h
@@ -141,7 +141,7 @@ struct net_iov *
 net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding);
 void net_devmem_free_dmabuf(struct net_iov *ppiov);
 
-bool net_is_devmem_iov(struct net_iov *niov);
+
 struct net_devmem_dmabuf_binding *
 net_devmem_get_binding(struct sock *sk, unsigned int dmabuf_id);
 struct net_iov *
@@ -214,11 +214,6 @@ static inline u32 net_devmem_iov_binding_id(const struct net_iov *niov)
 	return 0;
 }
 
-static inline bool net_is_devmem_iov(struct net_iov *niov)
-{
-	return false;
-}
-
 static inline struct net_devmem_dmabuf_binding *
 net_devmem_get_binding(struct sock *sk, unsigned int dmabuf_id)
 {
-- 
2.52.0.457.g6b5491de43-goog