netdev - [PATCH] net: don't check skb

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Date:   Wed, 15 Jun 2022 11:24:26 +0800
From:   Sieng Piaw Liew <liew.s.piaw@...il.com>
To:     davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Sieng Piaw Liew <liew.s.piaw@...il.com>
Subject: [PATCH] net: don't check skb_count twice

NAPI cache skb_count is being checked twice without condition. Change to
checking the second time only if the first check is run.

Signed-off-by: Sieng Piaw Liew <liew.s.piaw@...il.com>
---
 net/core/skbuff.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 5b3559cb1d82..c426adff6d96 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -172,13 +172,14 @@ static struct sk_buff *napi_skb_cache_get(void)
 	struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
 	struct sk_buff *skb;
 
-	if (unlikely(!nc->skb_count))
+	if (unlikely(!nc->skb_count)) {
 		nc->skb_count = kmem_cache_alloc_bulk(skbuff_head_cache,
 						      GFP_ATOMIC,
 						      NAPI_SKB_CACHE_BULK,
 						      nc->skb_cache);
-	if (unlikely(!nc->skb_count))
-		return NULL;
+		if (unlikely(!nc->skb_count))
+			return NULL;
+	}
 
 	skb = nc->skb_cache[--nc->skb_count];
 	kasan_unpoison_object_data(skbuff_head_cache, skb);
-- 
2.17.1