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>

1 files changed, 15 insertions, 2 deletions

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 2beda824636..27002dffe7e 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);