skbuff: use __build_skb_around() in __alloc_skb()

Just call __build_skb_around() instead of open-coding it.
Signed-off-by: Alexander Lobakin <alobakin@pm.me>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/skbuff.c

@@ -326,7 +326,6 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
 			    int flags, int node)
 {
 	struct kmem_cache *cache;
-	struct skb_shared_info *shinfo;
 	struct sk_buff *skb;
 	u8 *data;
 	bool pfmemalloc;
@@ -366,21 +365,8 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
 	 * the tail pointer in struct sk_buff!
 	 */
 	memset(skb, 0, offsetof(struct sk_buff, tail));
-	/* Account for allocated memory : skb + skb->head */
-	skb->truesize = SKB_TRUESIZE(size);
+	__build_skb_around(skb, data, 0);
 	skb->pfmemalloc = pfmemalloc;
-	refcount_set(&skb->users, 1);
-	skb->head = data;
-	skb->data = data;
-	skb_reset_tail_pointer(skb);
-	skb->end = skb->tail + size;
-	skb->mac_header = (typeof(skb->mac_header))~0U;
-	skb->transport_header = (typeof(skb->transport_header))~0U;
-
-	/* make sure we initialize shinfo sequentially */
-	shinfo = skb_shinfo(skb);
-	memset(shinfo, 0, offsetof(struct skb_shared_info, dataref));
-	atomic_set(&shinfo->dataref, 1);
 
 	if (flags & SKB_ALLOC_FCLONE) {
 		struct sk_buff_fclones *fclones;
@@ -393,8 +379,6 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
 		fclones->skb2.fclone = SKB_FCLONE_CLONE;
 	}
 
-	skb_set_kcov_handle(skb, kcov_common_handle());
-
 	return skb;
 
 nodata: