[PATCH] net: add kerneldoc to skb_copy_bits()

[Eric Dumazet <eric.dumazet@gmail.com>]

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>
---
 net/core/skbuff.c |   17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 2beda82..d6c2958 100644
--- 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);