Re: [dpdk-dev] [PATCH 1/5] bus/vdev: add iteration filter on name

[Thomas Monjalon <thomas@monjalon.net>]

08/10/2018 08:46, Andrew Rybchenko:
> On 10/8/18 1:25 AM, Thomas Monjalon wrote:
> > A virtual device can be matched with following syntax:
> > 	bus=vdev,name=X
> >
> > Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
> > ---
> >   drivers/bus/vdev/vdev_params.c | 21 ++++++++++++++++++---
> >   1 file changed, 18 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/bus/vdev/vdev_params.c b/drivers/bus/vdev/vdev_params.c
> > index da270f2ec..133998c3e 100644
> > --- a/drivers/bus/vdev/vdev_params.c
> > +++ b/drivers/bus/vdev/vdev_params.c
> > @@ -2,6 +2,8 @@
> >    * Copyright 2018 Gaëtan Rivet
> >    */
> >   
> > +#include <string.h>
> > +
> >   #include <rte_dev.h>
> >   #include <rte_bus.h>
> >   #include <rte_kvargs.h>
> > @@ -11,10 +13,12 @@
> >   #include "vdev_private.h"
> >   
> >   enum vdev_params {
> > +	RTE_VDEV_PARAM_NAME,
> >   	RTE_VDEV_PARAM_MAX,
> >   };
> >   
> >   static const char * const vdev_params_keys[] = {
> > +	[RTE_VDEV_PARAM_NAME] = "name",
> >   	[RTE_VDEV_PARAM_MAX] = NULL,
> >   };
> >   
> > @@ -22,11 +26,22 @@ static int
> >   vdev_dev_match(const struct rte_device *dev,
> >   	       const void *_kvlist)
> >   {
> > +	int ret;
> >   	const struct rte_kvargs *kvlist = _kvlist;
> > +	char *name;
> > +
> > +	/* cannot pass const dev->name to rte_kvargs_process() */
> > +	name = strdup(dev->name);
> > +	if (name == NULL)
> > +		return -ENOMEM; /* interpreted as no match */
> 
> It is strange to see -ENOMEM and -1 returned from the same function.
> rte_dev_cmp_t does not return negative errno. It just says match /
> no match (greater / smaller than 0 if ordering is possible).
> So, -ENOMEM is really confusing here. I think just -1 should be used.

Yes, OK.

> > +	ret = rte_kvargs_process(kvlist,
> > +		vdev_params_keys[RTE_VDEV_PARAM_NAME],
> > +		rte_kvargs_strcmp, name);
> > +	free(name);
> > +	if (ret != 0)
> > +		return -1;
> >   
> > -	(void) kvlist;
> > -	(void) dev;
> > -	return 0;
> > +	return ret;
> 
> I'm not sure that I understand why 'ret' is returned here
> instead of 0. Above check guarantees that ret==0.
> If you change it, it should be a good reason.

Right

Thanks for the review!