Hi Lucas,
On Wed, Nov 06, 2019 at 08:28:43PM +0000, Lucas wrote:
> Jan Klemkow <j.klem...@wemelug.de> wrote:
> > the following diff simplifies the error handling of MGETHDR() in
> > tcp_output(). Jumps earlier to out, prevents a double check of NULL and
> > makes the code more readable.
> >
> > OK?
> >
> > Bye,
> > Jan
> >
> > Index: netinet/tcp_output.c
> > ===================================================================
> > RCS file: /cvs/src/sys/netinet/tcp_output.c,v
> > retrieving revision 1.128
> > diff -u -p -r1.128 tcp_output.c
> > --- netinet/tcp_output.c 10 Nov 2018 18:40:34 -0000 1.128
> > +++ netinet/tcp_output.c 6 Nov 2019 14:34:40 -0000
> > @@ -652,17 +652,17 @@ send:
> > m->m_data -= hdrlen;
> > #else
> > MGETHDR(m, M_DONTWAIT, MT_HEADER);
> > - if (m != NULL && max_linkhdr + hdrlen > MHLEN) {
> > + if (m == NULL) {
> > + error = ENOBUFS;
> > + goto out;
> > + }
> > + if (max_linkhdr + hdrlen > MHLEN) {
> > MCLGET(m, M_DONTWAIT);
> > if ((m->m_flags & M_EXT) == 0) {
> > m_freem(m);
> > m = NULL;
> > }
> > }
> > - if (m == NULL) {
> > - error = ENOBUFS;
> > - goto out;
> > - }
> > m->m_data += max_linkhdr;
> > m->m_len = hdrlen;
>
> I might be missing something, but m can be NULL here, if (m->m_flags &
> M_EXT) == 0.
Yes, you are right. I missed that.
Thank,
Jan
