[libvirt] [PATCH 2/3] lxc: Turn @veths into a string list in virLXCProcessStart

[Erik Skultety]

On Fri, Jul 27, 2018 at 05:02:36PM +0200, Erik Skultety wrote:
> On Fri, Jul 27, 2018 at 02:34:41PM +0200, Michal Privoznik wrote:
> > On 07/27/2018 10:37 AM, Erik Skultety wrote:
> > > On Thu, Jul 26, 2018 at 05:36:28PM +0200, Michal Privoznik wrote:
> > >> This way it will be easier to use autofree.
> > >>
> > >> Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
> > >> ---
> > >>  src/lxc/lxc_process.c | 24 +++++++++---------------
> > >>  1 file changed, 9 insertions(+), 15 deletions(-)
> > >>
> > >> diff --git a/src/lxc/lxc_process.c b/src/lxc/lxc_process.c
> > >> index d021a890f7..3ac39d598c 100644
> > >> --- a/src/lxc/lxc_process.c
> > >> +++ b/src/lxc/lxc_process.c
> > >> @@ -514,8 +514,7 @@ static int virLXCProcessSetupNamespaces(virConnectPtr conn,
> > >>   * virLXCProcessSetupInterfaces:
> > >>   * @conn: pointer to connection
> > >>   * @def: pointer to virtual machine structure
> > >> - * @nveths: number of interfaces
> > >> - * @veths: interface names
> > >> + * @veths: string list of interface names
> > >>   *
> > >>   * Sets up the container interfaces by creating the veth device pairs and
> > >>   * attaching the parent end to the appropriate bridge.  The container end
> > >> @@ -525,7 +524,6 @@ static int virLXCProcessSetupNamespaces(virConnectPtr conn,
> > >>   */
> > >>  static int virLXCProcessSetupInterfaces(virConnectPtr conn,
> > >>                                          virDomainDefPtr def,
> > >> -                                        size_t *nveths,
> > >>                                          char ***veths)
> > >>  {
> > >>      int ret = -1;
> > >> @@ -534,6 +532,8 @@ static int virLXCProcessSetupInterfaces(virConnectPtr conn,
> > >>      virDomainNetDefPtr net;
> > >>      virDomainNetType type;
> > >>
> > >> +    *veths = NULL;
> > >> +
> > >>      for (i = 0; i < def->nnets; i++) {
> > >>          char *veth = NULL;
> > >>          virNetDevBandwidthPtr actualBandwidth;
> > >> @@ -549,9 +549,6 @@ static int virLXCProcessSetupInterfaces(virConnectPtr conn,
> > >>          if (virDomainNetAllocateActualDevice(def, net) < 0)
> > >>              goto cleanup;
> > >>
> > >> -        if (VIR_EXPAND_N(*veths, *nveths, 1) < 0)
> > >> -            goto cleanup;
> > >
> > > Contrary to what I said in the previous patch, I hadn't realized we were
> > > expanding a list by 1 in a loop before I looked at this patch. That is very
> > > inefficient and we'll keep doing that. Now I'm biased towards tracking the size
> > > of the list so that we can do VIR_EXPAND_N(*veths, 0, def->nnets) and then just
> > > add new elements, of course that would require tweaking the virStringListAdd
> > > more.
> > >
> >
> > Hold on. I'm not quite sure I follow. Are you suggesting to pre-allocate
> > the string list and ditch virStringListAdd completely? Something like
> > this?
>
> Yes, that's the idea. Originally, I didn't think dropping virStringListAdd would
> be necessary, but it's clear from the snippet below that it would.
>
> Erik

Something I forgot:

Reviewed-by: Erik Skultety <eskultet at redhat.com>

>
> >
> > diff --git i/src/lxc/lxc_process.c w/src/lxc/lxc_process.c
> > index 6eef17d1ce..33c806630b 100644
> > --- i/src/lxc/lxc_process.c
> > +++ w/src/lxc/lxc_process.c
> > @@ -532,7 +532,8 @@ static int virLXCProcessSetupInterfaces(virConnectPtr conn,
> >      virDomainNetDefPtr net;
> >      virDomainNetType type;
> >
> > -    *veths = NULL;
> > +    if (VIR_ALLOC_N(*veths, def->nnets + 1) < 0)
> > +        return -1;
> >
> >      for (i = 0; i < def->nnets; i++) {
> >          char *veth = NULL;
> > @@ -601,8 +602,7 @@ static int virLXCProcessSetupInterfaces(virConnectPtr conn,
> >              }
> >          }
> >
> > -        if (virStringListAdd(veths, veth) < 0)
> > -            goto cleanup;
> > +        (*veths)[i] = veth;
> >
> >          if (VIR_STRDUP(def->nets[i]->ifname_guest_actual, veth) < 0)
> >              goto cleanup;
> >
> >
> > Michal
> >
> > --
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>
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