Re: [dpdk-dev] [PATCH v3 4/4] eal: simplify parameters of hotplug functions

[Thomas Monjalon <thomas@monjalon.net>]

01/10/2018 13:26, Andrew Rybchenko:
> On 9/28/18 7:21 PM, Thomas Monjalon wrote:
> > All information about a device to probe can be grouped
> > in a common string, which is what we usually call devargs.
> > An application should not have to parse this string before
> > calling the EAL probe function.
> > And the syntax could evolve to be more complex and support
> > matching multiple devices in one string.
> > That's why the bus name and device name should be removed from
> > rte_eal_hotplug_add().
> > Instead of changing this function, a simpler one is added
> > and used in the old one, which may be deprecated later.
> >
> > When removing a device, we already know its rte_device handle
> > which can be directly passed as parameter of rte_eal_hotplug_remove().
> > If the rte_device is not known, it can be retrieved with the devargs,
> > by iterating in the device list (future RTE_DEV_FOREACH()).
> > Similarly to the probing case, a new function is added
> > and used in the old one, which may be deprecated later.
> > The new function is used in failsafe, because the replacement is easy.
> >
> > Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
> 
> Minor memory leak below, when fixed:
> 
> Reviewed-by: Andrew Rybchenko <arybchenko@solarflare.com>
> 
> <...>
> 
> > diff --git a/lib/librte_eal/common/eal_common_dev.c b/lib/librte_eal/common/eal_common_dev.c
> > index a9be58edf..b40e4c0d0 100644
> > --- a/lib/librte_eal/common/eal_common_dev.c
> > +++ b/lib/librte_eal/common/eal_common_dev.c
> > @@ -129,46 +129,57 @@ int rte_eal_dev_detach(struct rte_device *dev)
> >   
> >   int
> >   rte_eal_hotplug_add(const char *busname, const char *devname,
> > -		    const char *devargs)
> > +		    const char *drvargs)
> > +{
> > +	char *devargs = NULL;
> > +	int size, length = -1;
> > +
> > +	do { /* 2 iterations: first is to know string length */
> > +		size = length + 1;
> > +		length = snprintf(devargs, size, "%s:%s,%s", busname, devname, drvargs);
> > +		if (length >= size)
> > +			devargs = malloc(length + 1);
> > +		if (devargs == NULL)
> > +			return -ENOMEM;
> > +	} while (size == 0);
> > +
> > +	return rte_dev_probe(devargs);
> 
> I think we should free devargs after the call.

Good catch!
Will fix in v4, thank you.