[dpdk-dev] [PATCH v3 3/8] net/failsafe: support probed sub-devices getting

[Matan Azrad]

Hi Gaetan

From: Gaëtan Rivet, Tuesday, January 16, 2018 1:09 PM
> Hi Matan,
> 
> I'n not fond of the commit title, how about:
> 
> [PATCH v3 3/8] net/failsafe: add probed etherdev capture
> 
> ?
> 
OK, no problem.

> On Tue, Jan 09, 2018 at 02:47:28PM +0000, Matan Azrad wrote:
> > Previous fail-safe code didn't support getting probed sub-devices and
> > failed when it tried to probe them.
> >
> > Skip fail-safe sub-device probing when it already was probed.
> >
> > Signed-off-by: Matan Azrad <matan at mellanox.com>
> > Cc: Gaetan Rivet <gaetan.rivet at 6wind.com>
> > ---
> >  doc/guides/nics/fail_safe.rst       |  5 ++++
> >  drivers/net/failsafe/failsafe_eal.c | 60
> > ++++++++++++++++++++++++-------------
> >  2 files changed, 45 insertions(+), 20 deletions(-)
> >
> > diff --git a/doc/guides/nics/fail_safe.rst
> > b/doc/guides/nics/fail_safe.rst index 5b1b47e..b89e53b 100644
> > --- a/doc/guides/nics/fail_safe.rst
> > +++ b/doc/guides/nics/fail_safe.rst
> > @@ -115,6 +115,11 @@ Fail-safe command line parameters
> >    order to take only the last line into account (unlike ``exec()``) at every
> >    probe attempt.
> >
> > +.. note::
> > +
> > +   In case of whitelist sub-device probed by EAL, fail-safe PMD will take the
> device
> > +   as is, which means that EAL device options are taken in this case.
> > +
> >  - **mac** parameter [MAC address]
> >
> >    This parameter allows the user to set a default MAC address to the
> > fail-safe diff --git a/drivers/net/failsafe/failsafe_eal.c
> > b/drivers/net/failsafe/failsafe_eal.c
> > index 19d26f5..7bc7453 100644
> > --- a/drivers/net/failsafe/failsafe_eal.c
> > +++ b/drivers/net/failsafe/failsafe_eal.c
> > @@ -36,39 +36,59 @@
> >  #include "failsafe_private.h"
> >
> >  static int
> > +fs_get_port_by_device_name(const char *name, uint16_t *port_id)
> 
> The naming convention for the failsafe driver is
> 
>       namespace_object_sub-object_action()
> 
OK.
> With an ordering of objects by their scope (std, rte, failsafe, file).
> Also, "get" as an action is not descriptive enough.
> 
Isn't "get by device name" descriptive? 
> static int
> fs_ethdev_capture(const char *name, uint16_t *port_id);
> 
You miss here the main reason why we need this function instead of using rte_eth_dev_get_port_by_name.
The reason we need this function is because we want to find the device by the device name and not ethdev name.
What's about  fs_port_capture_by_device_name?

Maybe comparing it to device->devargs->name is better, What do you think?

> > +{
> > +	uint16_t pid;
> > +	size_t len;
> > +
> > +	if (name == NULL) {
> > +		DEBUG("Null pointer is specified\n");
> > +		return -EINVAL;
> > +	}
> > +	len = strlen(name);
> > +	RTE_ETH_FOREACH_DEV(pid) {
> > +		if (!strncmp(name, rte_eth_devices[pid].device->name,
> len)) {
> > +			*port_id = pid;
> > +			return 0;
> > +		}
> > +	}
> > +	return -ENODEV;
> > +}
> > +
> > +static int
> >  fs_bus_init(struct rte_eth_dev *dev)
> >  {
> >  	struct sub_device *sdev;
> >  	struct rte_devargs *da;
> >  	uint8_t i;
> > -	uint16_t j;
> > +	uint16_t pid;
> >  	int ret;
> >
> >  	FOREACH_SUBDEV(sdev, i, dev) {
> >  		if (sdev->state != DEV_PARSED)
> >  			continue;
> >  		da = &sdev->devargs;
> > -		ret = rte_eal_hotplug_add(da->bus->name,
> > -					  da->name,
> > -					  da->args);
> > -		if (ret) {
> > -			ERROR("sub_device %d probe failed %s%s%s", i,
> > -			      rte_errno ? "(" : "",
> > -			      rte_errno ? strerror(rte_errno) : "",
> > -			      rte_errno ? ")" : "");
> > -			continue;
> > -		}
> > -		RTE_ETH_FOREACH_DEV(j) {
> > -			if (strcmp(rte_eth_devices[j].device->name,
> > -				    da->name) == 0) {
> > -				ETH(sdev) = &rte_eth_devices[j];
> > -				break;
> > +		if (fs_get_port_by_device_name(da->name, &pid) != 0) {
> > +			ret = rte_eal_hotplug_add(da->bus->name,
> > +						  da->name,
> > +						  da->args);
> > +			if (ret) {
> > +				ERROR("sub_device %d probe failed
> %s%s%s", i,
> > +				      rte_errno ? "(" : "",
> > +				      rte_errno ? strerror(rte_errno) : "",
> > +				      rte_errno ? ")" : "");
> > +				continue;
> >  			}
> > +			if (fs_get_port_by_device_name(da->name, &pid)
> != 0) {
> > +				ERROR("sub_device %d init went wrong", i);
> > +				return -ENODEV;
> > +			}
> > +		} else {
> > +			/* Take control of device probed by EAL options. */
> > +			DEBUG("Taking control of a probed sub device"
> > +			      " %d named %s", i, da->name);
> 
> In this case, the devargs of the probed device must be copied within the sub-
> device definition and removed from the EAL using the proper rte_devargs
> API.
> 
> Note that there is no rte_devargs copy function. You can use
> rte_devargs_parse instead, "parsing" again the original devargs into the sub-
> device one. It is necessary for complying with internal rte_devargs
> requirements (da->args being malloc-ed, at the moment, but may evolve).
> 
> The rte_eal_devargs_parse function is not easy enough to use right now,
> you will have to build a devargs string (using snprintf) and submit it.
> I proposed a change this release for it but it will not make it for 18.02, that
> would have simplified your implementation.
> 

Got you. You right we need to remove the created devargs in fail-safe parse level.
What do you think about checking it in the parse level and avoid the new devargs creation?
Also to do the copy in parse level(same method as we are doing in probe level)?

> --
> Gaëtan Rivet
> 6WIND