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From:   Vasily Averin <vvs@virtuozzo.com>
Subject: [PATCH NET 5/7] vrf: use pskb_realloc_headroom in vrf_finish_output
To:     "David S. Miller" <davem@davemloft.net>,
        Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        David Ahern <dsahern@kernel.org>,
        Jakub Kicinski <kuba@kernel.org>,
        Eric Dumazet <eric.dumazet@gmail.com>
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org
References: <74e90fba-df9f-5078-13de-41df54d2b257@virtuozzo.com>
 <cover.1626093470.git.vvs@virtuozzo.com>
Message-ID: <b17496f3-7471-319d-62f7-d289e6962778@virtuozzo.com>
Date:   Mon, 12 Jul 2021 16:27:11 +0300
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Precedence: bulk

Unlike skb_realloc_headroom, new helper pskb_realloc_headroom
does not allocate a new skb if possible.

Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
---
 drivers/net/vrf.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index 28a6c4c..74b9538 100644
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -863,18 +863,12 @@ static int vrf_finish_output(struct net *net, struct sock *sk, struct sk_buff *s
 
 	/* Be paranoid, rather than too clever. */
 	if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) {
-		struct sk_buff *skb2;
+		skb = pskb_realloc_headroom(skb, hh_len);
 
-		skb2 = skb_realloc_headroom(skb, LL_RESERVED_SPACE(dev));
-		if (!skb2) {
-			ret = -ENOMEM;
-			goto err;
+		if (!skb) {
+			dev->stats.tx_errors++;
+			return -ENOMEM;
 		}
-		if (skb->sk)
-			skb_set_owner_w(skb2, skb->sk);
-
-		consume_skb(skb);
-		skb = skb2;
 	}
 
 	rcu_read_lock_bh();
-- 
1.8.3.1