Re: [dpdk-dev] [PATCH 2/2] pci: rearrange logic from compare loop

[Stephen Hemminger <stephen@networkplumber.org>]

There is no need to initialize a variable that is only used as a loop
variable.



On Tue, Apr 14, 2015 at 2:30 AM, Qiu, Michael <michael.qiu@intel.com> wrote:

> On 4/14/2015 6:11 AM, Stephen Hemminger wrote:
> > Do some cleanup of pci scan loop.
> >   * check errors first
> >   * don't initialize variables where not necessary
>
> Why? It should be better to initialize variables when define it.
>
> Thanks,
> Michael
> >   * cuddle else (follow existing style)
> >   * chop off conditional after return
> >
> > Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> >
> > ---
> >  lib/librte_eal/linuxapp/eal/eal_pci.c | 24 ++++++++++++------------
> >  1 file changed, 12 insertions(+), 12 deletions(-)
> >
> > diff --git a/lib/librte_eal/linuxapp/eal/eal_pci.c
> b/lib/librte_eal/linuxapp/eal/eal_pci.c
> > index c98a778..d96b1c4 100644
> > --- a/lib/librte_eal/linuxapp/eal/eal_pci.c
> > +++ b/lib/librte_eal/linuxapp/eal/eal_pci.c
> > @@ -337,6 +337,12 @@ pci_scan_one(const char *dirname, uint16_t domain,
> uint8_t bus,
> >       /* parse driver */
> >       snprintf(filename, sizeof(filename), "%s/driver", dirname);
> >       ret = pci_get_kernel_driver_by_path(filename, driver);
> > +     if (ret < 0) {
> > +             RTE_LOG(ERR, EAL, "Fail to get kernel driver\n");
> > +             free(dev);
> > +             return -1;
> > +     }
> > +
> >       if (!ret) {
> >               if (!strcmp(driver, "vfio-pci"))
> >                       dev->kdrv = RTE_KDRV_VFIO;
> > @@ -346,37 +352,31 @@ pci_scan_one(const char *dirname, uint16_t domain,
> uint8_t bus,
> >                       dev->kdrv = RTE_KDRV_UIO_GENERIC;
> >               else
> >                       dev->kdrv = RTE_KDRV_UNKNOWN;
> > -     } else if (ret < 0) {
> > -             RTE_LOG(ERR, EAL, "Fail to get kernel driver\n");
> > -             free(dev);
> > -             return -1;
> >       } else
> >               dev->kdrv = RTE_KDRV_UNKNOWN;
> >
> >       /* device is valid, add in list (sorted) */
> >       if (TAILQ_EMPTY(&pci_device_list)) {
> >               TAILQ_INSERT_TAIL(&pci_device_list, dev, next);
> > -     }
> > -     else {
> > -             struct rte_pci_device *dev2 = NULL;
> > +     } else {
> > +             struct rte_pci_device *dev2;
> >               int ret;
> >
> >               TAILQ_FOREACH(dev2, &pci_device_list, next) {
> >                       ret = rte_eal_compare_pci_addr(&dev->addr,
> &dev2->addr);
> >                       if (ret > 0)
> >                               continue;
> > -                     else if (ret < 0) {
> > +
> > +                     if (ret < 0) {
> >                               TAILQ_INSERT_BEFORE(dev2, dev, next);
> > -                             return 0;
> >                       } else { /* already registered */
> >                               dev2->kdrv = dev->kdrv;
> >                               dev2->max_vfs = dev->max_vfs;
> > -                             memmove(dev2->mem_resource,
> > -                                     dev->mem_resource,
> > +                             memmove(dev2->mem_resource,
> dev->mem_resource,
> >                                       sizeof(dev->mem_resource));
> >                               free(dev);
> > -                             return 0;
> >                       }
> > +                     return 0;
> >               }
> >               TAILQ_INSERT_TAIL(&pci_device_list, dev, next);
> >       }
>
>