Re: [dpdk-dev] [PATCH] librte_vhost: Fix the path test issue

["Ouyang, Changchun" <changchun.ouyang@intel.com>]

Hi Huawei, 
Thanks for the comments,
And my response as follows.

> -----Original Message-----
> From: Xie, Huawei
> Sent: Thursday, November 6, 2014 10:39 AM
> To: Ouyang, Changchun; dev@dpdk.org
> Subject: RE: [dpdk-dev] [PATCH] librte_vhost: Fix the path test issue
> 
> >  		path = realpath(memfile, resolved_path);
> > -		if (path == NULL) {
> > +		if ((path == NULL) && (strlen(resolved_path) == 0)) {
> >  			RTE_LOG(ERR, VHOST_CONFIG,
> >  				"(%"PRIu64") Failed to resolve fd directory\n",
> >  				dev->device_fh);
> Changchun:
> For some strange file, according to API description, we shouldn't check
> resolved_path as it is undefined.
> To make the loop go on, we could use "continue" when we detect path is
> NULL.
> 
> RETURN VALUE
>        If there is no error, realpath() returns a pointer to the resolved_path.
> 
>        Otherwise it returns a NULL pointer, and the contents of the array
> resolved_path are undefined, and errno is set to indicate the error.

After my investigation this issue and find out using continue doesn't work.

The reason is procmap.fname itself is "/dev/hugepages/qemu_back_mem.pc.ram.zxfqLq",
It is not a normal path, so in this case, path is null, while resolved-path is /dev/hugepages/qemu_back_mem.pc.ram.zxfqLq

If 'continue' is used, then procmap.fname could not be hit in the directory list,
And then  app will exit after report:　Failed to find memory file for pid....

So I have to keep it.

Thanks again
Changchun