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

["Qiu, Michael" <michael.qiu@intel.com>]

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);
>  	}