Hello Jan,
Jan Klemkow <[email protected]> wrote:
> Hi,
>
> 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.
> if (len <= m_trailingspace(m)) {
> @@ -701,16 +701,16 @@ send:
> tcpstat_inc(tcps_sndwinup);
>
> 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;
And same here.
-Lucas
