net: caif: use skb helpers instead of open-coding them

Use existing skb_put_data() and skb_trim() instead of open-coding them,
with the skb_put_data() first so that logically, `skb` still contains the
data to be copied in its data..tail area when skb_put_data() reads it.
This change on its own is a cleanup, and it is also necessary for potential
future integration of skbuffs with things like KASAN.

Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 11 deletions

diff --git a/net/caif/cfpkt_skbuff.c b/net/caif/cfpkt_skbuff.c
index 38c2b7a890dd..37ac5ca0ffdf 100644
--- a/net/caif/cfpkt_skbuff.c
+++ b/net/caif/cfpkt_skbuff.c
@@ -319,16 +319,12 @@ struct cfpkt *cfpkt_append(struct cfpkt *dstpkt,
                 if (tmppkt == NULL)
                         return NULL;
                 tmp = pkt_to_skb(tmppkt);
-                skb_set_tail_pointer(tmp, dstlen);
-                tmp->len = dstlen;
-                memcpy(tmp->data, dst->data, dstlen);
+                skb_put_data(tmp, dst->data, dstlen);
                 cfpkt_destroy(dstpkt);
                 dst = tmp;
         }
-        memcpy(skb_tail_pointer(dst), add->data, skb_headlen(add));
+        skb_put_data(dst, add->data, skb_headlen(add));
         cfpkt_destroy(addpkt);
-        dst->tail += addlen;
-        dst->len += addlen;
         return skb_to_pkt(dst);
 }
 
@@ -359,13 +355,11 @@ struct cfpkt *cfpkt_split(struct cfpkt *pkt, u16 pos)
         if (skb2 == NULL)
                 return NULL;
 
+        skb_put_data(skb2, split, len2nd);
+
         /* Reduce the length of the original packet */
-        skb_set_tail_pointer(skb, pos);
-        skb->len = pos;
+        skb_trim(skb, pos);
 
-        memcpy(skb2->data, split, len2nd);
-        skb2->tail += len2nd;
-        skb2->len += len2nd;
         skb2->priority = skb->priority;
         return skb_to_pkt(skb2);
 }