net: add kerneldoc to skb_copy_bits()

Since skb_copy_bits() is called from assembly, add a fat comment to make
clear we should think twice before changing its prototype.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 2beda82..27002df 100644 (file)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1369,8 +1369,21 @@ pull_pages:
 }
 EXPORT_SYMBOL(__pskb_pull_tail);
 
-/* Copy some data bits from skb to kernel buffer. */
-
+/**
+ *     skb_copy_bits - copy bits from skb to kernel buffer
+ *     @skb: source skb
+ *     @offset: offset in source
+ *     @to: destination buffer
+ *     @len: number of bytes to copy
+ *
+ *     Copy the specified number of bytes from the source skb to the
+ *     destination buffer.
+ *
+ *     CAUTION ! :
+ *             If its prototype is ever changed,
+ *             check arch/{*}/net/{*}.S files,
+ *             since it is called from BPF assembly code.
+ */
 int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len)
 {
        int start = skb_headlen(skb);