netdev - [PATCH] net: helper function for skb

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Message-ID: <20220616122617.GA2237@debian>
Date:   Thu, 16 Jun 2022 14:26:29 +0200
From:   Richard Gobert <richardbgobert@...il.com>
To:     davem@...emloft.net, kuba@...nel.org, pabeni@...hat.com,
        edumazet@...gle.com, brouer@...hat.com, imagedong@...cent.com,
        vasily.averin@...ux.dev, talalahmad@...gle.com,
        luiz.von.dentz@...el.com, jk@...econstruct.com.au,
        netdev@...r.kernel.org
Subject: [PATCH] net: helper function for skb_shift

Move the len fields manipulation in the skbs to a helper function.
There is a comment specifically requesting this. This improves the
readability of skb_shift.

Signed-off-by: Richard Gobert <richardbgobert@...il.com>
---
 net/core/skbuff.c | 22 ++++++++++++++--------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 30b523fa4ad2..8a0a941915e8 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3508,6 +3508,19 @@ static int skb_prepare_for_shift(struct sk_buff *skb)
 }
 
 /**
+ * skb_shift_len - Update length fields of skbs when shifting.
+ */
+static inline void skb_shift_len(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen)
+{
+	skb->len -= shiftlen;
+	skb->data_len -= shiftlen;
+	skb->truesize -= shiftlen;
+	tgt->len += shiftlen;
+	tgt->data_len += shiftlen;
+	tgt->truesize += shiftlen;
+}
+
+/**
  * skb_shift - Shifts paged data partially from skb to another
  * @tgt: buffer into which tail data gets added
  * @skb: buffer from which the paged data comes from
@@ -3634,14 +3647,7 @@ int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen)
 	tgt->ip_summed = CHECKSUM_PARTIAL;
 	skb->ip_summed = CHECKSUM_PARTIAL;
 
-	/* Yak, is it really working this way? Some helper please? */
-	skb->len -= shiftlen;
-	skb->data_len -= shiftlen;
-	skb->truesize -= shiftlen;
-	tgt->len += shiftlen;
-	tgt->data_len += shiftlen;
-	tgt->truesize += shiftlen;
-
+	skb_shift_len(tgt, skb, shiftlen);
 	return shiftlen;
 }
 
-- 
2.36.1