Re: [PATCH v5 12/12] eal: make virtual driver probe and remove take rte_vdev_device

["Gaëtan Rivet" <gaetan.rivet@6wind.com>]

On Tue, Jun 27, 2017 at 02:58:55PM +0100, Bruce Richardson wrote:
> On Mon, Jun 26, 2017 at 02:22:10AM +0200, Gaetan Rivet wrote:
> > From: Jan Blunck <jblunck@infradead.org>
> > 
> > This is a preparation to embed the generic rte_device into the rte_eth_dev
> > also for virtual devices.
> > 
> > Signed-off-by: Jan Blunck <jblunck@infradead.org>
> > Signed-off-by: Gaetan Rivet <gaetan.rivet@6wind.com>
> > ---
> >  lib/librte_eal/common/eal_common_dev.c | 93 ++++++++++++++++++++++++++--------
> >  1 file changed, 71 insertions(+), 22 deletions(-)
> > 
> > diff --git a/lib/librte_eal/common/eal_common_dev.c b/lib/librte_eal/common/eal_common_dev.c
> > index a400ddd..d83ae41 100644
> > --- a/lib/librte_eal/common/eal_common_dev.c
> > +++ b/lib/librte_eal/common/eal_common_dev.c
> > @@ -37,6 +37,7 @@
> >  #include <inttypes.h>
> >  #include <sys/queue.h>
> >  
> > +#include <rte_bus.h>
> >  #include <rte_dev.h>
> >  #include <rte_devargs.h>
> >  #include <rte_debug.h>
> > @@ -45,50 +46,98 @@
> >  
> >  #include "eal_private.h"
> >  
> > +static int cmp_detached_dev_name(const struct rte_device *dev,
> > +	const void *_name)
> > +{
> > +	const char *name = _name;
> > +
> > +	/* skip attached devices */
> > +	if (dev->driver)
> > +		return 0;
> > +
> 
> Does returning 0 from this function not mean that all already-attached
> devices with match? Is that really what we want, as it doesn't seem to
> match the logic in the function below. Please explain if I'm wrong here.
> 

Yes, this was a mistake, good catch.

> > +	return strcmp(dev->name, name);
> > +}
> > +
> >  int rte_eal_dev_attach(const char *name, const char *devargs)
> >  {
> > -	struct rte_pci_addr addr;
> > +	struct rte_device *dev;
> > +	int ret;
> >  
> >  	if (name == NULL || devargs == NULL) {
> >  		RTE_LOG(ERR, EAL, "Invalid device or arguments provided\n");
> >  		return -EINVAL;
> >  	}
> >  
> > -	if (eal_parse_pci_DomBDF(name, &addr) == 0) {
> > -		if (rte_pci_probe_one(&addr) < 0)
> > -			goto err;
> > +	dev = rte_bus_find_device(cmp_detached_dev_name, name, NULL);
> > +	if (dev) {
> > +		struct rte_bus *bus;
> > +
> > +		bus = rte_bus_find_by_device(dev);
> > +		if (!bus) {
> > +			RTE_LOG(ERR, EAL, "Cannot find bus for device (%s)\n",
> > +				name);
> > +			return -EINVAL;
> > +		}
> >  
> > -	} else {
> > -		if (rte_vdev_init(name, devargs))
> > -			goto err;
> > +		if (!bus->plug) {
> > +			RTE_LOG(ERR, EAL, "Bus function not supported\n");
> > +			return -ENOTSUP;
> > +		}
> > +
> > +		ret = (bus->plug(dev->devargs) == NULL);
> > +		goto out;
> >  	}
> >  
> > -	return 0;
> > +	/*
> > +	 * If we haven't found a bus device the user meant to "hotplug" a
> > +	 * virtual device instead.
> > +	 */
> > +	ret = rte_vdev_init(name, devargs);
> > +out:
> > +	if (ret)
> > +		RTE_LOG(ERR, EAL, "Driver cannot attach the device (%s)\n",
> > +			name);
> > +	return ret;
> > +}
> > +
> <snip>
> 
> Regards,
> /Bruce

On Tue, Jun 27, 2017 at 03:00:58PM +0100, Bruce Richardson wrote:
> I'm also not sure about the commit title of this patch. It doesn't
> match
> my understanding of what the patch does.
>
> /Bruce

I have a few issues with this patch myself. However, to properly fix
those, I need the rte_devargs evolutions coming afterward.

As an intermediate step, this is good enough to support the current
rte_dev attach / detach API and follow the new hotplug API. It makes
sense to have it as part of this series, so that the latter is self-contained
and internally consistent.

But it will evolve.

I will rewrite the commit log.

-- 
Gaëtan Rivet
6WIND