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Date:   Mon, 11 Jan 2021 18:28:38 +0000
To:     "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>
From:   Alexander Lobakin <alobakin@pm.me>
Cc:     Eric Dumazet <edumazet@google.com>,
        Edward Cree <ecree@solarflare.com>,
        Jonathan Lemon <jonathan.lemon@gmail.com>,
        Willem de Bruijn <willemb@google.com>,
        Miaohe Lin <linmiaohe@huawei.com>,
        Alexander Lobakin <alobakin@pm.me>,
        Steffen Klassert <steffen.klassert@secunet.com>,
        Guillaume Nault <gnault@redhat.com>,
        Yadu Kishore <kyk.segfault@gmail.com>,
        Al Viro <viro@zeniv.linux.org.uk>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Reply-To: Alexander Lobakin <alobakin@pm.me>
Subject: [PATCH net-next 2/5] skbuff: open-code __build_skb() inside __napi_alloc_skb()
Message-ID: <20210111182801.12609-2-alobakin@pm.me>
In-Reply-To: <20210111182801.12609-1-alobakin@pm.me>
References: <20210111182655.12159-1-alobakin@pm.me> <20210111182801.12609-1-alobakin@pm.me>
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Precedence: bulk

In preparation for skbuff_heads caching and reusing, open-code
__build_skb() inside __napi_alloc_skb() with factoring out
the skbbuff_head allocation itself.
Note that the return value of __build_skb_around() is not checked
since it never returns anything except the given skb.

Signed-off-by: Alexander Lobakin <alobakin@pm.me>
---
 net/core/skbuff.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 17ae5e90f103..3c904c29efbb 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -485,6 +485,11 @@ struct sk_buff *__netdev_alloc_skb(struct net_device *=
dev, unsigned int len,
 }
 EXPORT_SYMBOL(__netdev_alloc_skb);
=20
+static struct sk_buff *__napi_decache_skb(struct napi_alloc_cache *nc)
+{
+=09return kmem_cache_alloc(skbuff_head_cache, GFP_ATOMIC);
+}
+
 /**
  *=09__napi_alloc_skb - allocate skbuff for rx in a specific NAPI instance
  *=09@napi: napi instance this buffer was allocated for
@@ -525,12 +530,15 @@ struct sk_buff *__napi_alloc_skb(struct napi_struct *=
napi, unsigned int len,
 =09if (unlikely(!data))
 =09=09return NULL;
=20
-=09skb =3D __build_skb(data, len);
+=09skb =3D __napi_decache_skb(nc);
 =09if (unlikely(!skb)) {
 =09=09skb_free_frag(data);
 =09=09return NULL;
 =09}
=20
+=09memset(skb, 0, offsetof(struct sk_buff, tail));
+=09__build_skb_around(skb, data, len);
+
 =09if (nc->page.pfmemalloc)
 =09=09skb->pfmemalloc =3D 1;
 =09skb->head_frag =3D 1;
--=20
2.30.0