kern/134355: [mbuf] comments for m_getm2 inconsistent with behaviour

[Martin Karsten]

I must have missed this email. Yes, changing the comment is definitely enough to
rectify the inconsistency.

Thanks,
Martin

On 06/17/2009 04:13 PM, vwe at FreeBSD.org wrote:
> Old Synopsis: [kernel] comments for m_getm2 inconsistent with behaviour
> New Synopsis: [mbuf] comments for m_getm2 inconsistent with behaviour
> 
> State-Changed-From-To: open->analyzed
> State-Changed-By: vwe
> State-Changed-When: Wed Jun 17 20:07:52 UTC 2009
> State-Changed-Why: 
> Martin,
> thank you for your submission.
> In the first place I thought you've found a code bug but while carefully
> analyzing usage of m_getm2(), I haven't been able to to find a sign
> of trouble. I agree current implementation isn't intentional and might
> easily lead into misuse of m_getmw() but the function is rarely used.
> I think the issue can be solved by "fixing" the leading comment by
> something like the following.
> 
> --- uipc_mbuf.c.orig	2009-06-17 22:03:53.000000000 +0200
> +++ uipc_mbuf.c	2009-06-17 22:06:24.000000000 +0200
> @@ -90,8 +90,9 @@
>   * Allocate a given length worth of mbufs and/or clusters (whatever fits
>   * best) and return a pointer to the top of the allocated chain.  If an
>   * existing mbuf chain is provided, then we will append the new chain
> - * to the existing one but still return the top of the newly allocated
> - * chain.
> + * to the existing one but still return the top of the pre-existing
> + * chain. If no pre-existing mbuf chain is given, we return the top
> + * of the new allocated mbuf chain.
>   */
>  struct mbuf *
>  m_getm2(struct mbuf *m, int len, int how, short type, int flags)
> 
> 
> http://www.freebsd.org/cgi/query-pr.cgi?pr=134355