[libvirt] [PATCH 11/24] hostdev: Remove redundant check
Andrea Bolognani
abologna at redhat.com
Thu Mar 10 17:21:51 UTC 2016
On Thu, 2016-03-10 at 12:01 -0500, John Ferlan wrote:
> On 03/07/2016 12:24 PM, Andrea Bolognani wrote:
> >
> > If 'last_processed_hostdev_vf != -1' is false then, since the
> > loop counter 'i' starts at 0, 'i <= last_processed_hostdev_vf'
> > can't possibly be true and the loop body will never be executed.
> >
> > Hence, the first check is completely redundant and can be safely
> > removed.
> > ---
> > src/util/virhostdev.c | 3 +--
> > 1 file changed, 1 insertion(+), 2 deletions(-)
> >
> Premise understood; however, Coverity has an issue...
Well, that's a first :P
> Way back here:
>
> 507 virPCIDeviceListPtr pcidevs = NULL;
>
> (1) Event var_tested_neg: Assigning: "last_processed_hostdev_vf" = a negative value.
> Also see events: [negative_returns]
>
> 508 int last_processed_hostdev_vf = -1;
>
>
> Eventually we enter this loop:
>
> for (i = 0; i < nhostdevs; i++) {
> virDomainHostdevDefPtr hostdev = hostdevs[i];
> if (!virHostdevIsPCINetDevice(hostdev))
> continue;
> if (virHostdevNetConfigReplace(hostdev, uuid,
> mgr->stateDir) < 0) {
> goto resetvfnetconfig;
> }
> last_processed_hostdev_vf = i;
> }
>
> If for some reason we "continue" (or not) and eventually "goto resetvfnetconfig;"
> before ever setting last_processed_hostdev_vf, then we get to the goto.,..
>
> > resetvfnetconfig:
> > - for (i = 0;
> > - last_processed_hostdev_vf != -1 && i <= last_processed_hostdev_vf; i++)
> and last_processed_hostdev_vf still == -1
>
> So that check needs to be there - perhaps just add an:
>
> if (last_processed_hostdev_vf > -1) {
> }
I fail to see how this is a problem: if last_processed_hostdev_vf
has never been assigned a value after being declared, then the
rewritten loop would be equivalent to
for (i = 0; i <= -1; i++) { ... }
which means the loop body will never be executed, just as
expected. Am I missing something?
Cheers.
--
Andrea Bolognani
Software Engineer - Virtualization Team
More information about the libvir-list
mailing list