[dpdk-dev] [PATCH v7 6/6] devargs: parse bus info

[Shreyansh Jain]

Hello Gaetan,

On Wednesday 05 July 2017 05:25 AM, Gaetan Rivet wrote:
> Signed-off-by: Gaetan Rivet <gaetan.rivet at 6wind.com>
> ---
>   lib/librte_eal/common/eal_common_devargs.c  | 42 ++++++++++++++++++++++++-----
>   lib/librte_eal/common/eal_common_vdev.c     |  6 +++--
>   lib/librte_eal/common/include/rte_devargs.h |  3 +++
>   3 files changed, 42 insertions(+), 9 deletions(-)
> 
> diff --git a/lib/librte_eal/common/eal_common_devargs.c b/lib/librte_eal/common/eal_common_devargs.c
> index ffa8ad9..102bd8d 100644
> --- a/lib/librte_eal/common/eal_common_devargs.c
> +++ b/lib/librte_eal/common/eal_common_devargs.c
> @@ -78,12 +78,23 @@ rte_eal_parse_devargs_str(const char *devargs_str,
>   	return 0;
>   }
>   
> +static int
> +bus_name_cmp(const struct rte_bus *bus, const void *_name)
> +{
> +	const char *name = _name;
> +
> +	return strncmp(bus->name, name,
> +		       strlen(bus->name));

Trivial: Any specific reason why this is split across multiple lines 
even though it is less than 80 chars in total?

> +}
> +
>   /* store a whitelist parameter for later parsing */
>   int
>   rte_eal_devargs_add(enum rte_devtype devtype, const char *devargs_str)
>   {
>   	struct rte_devargs *devargs = NULL;
> -	char *buf = NULL;
> +	struct rte_bus *bus = NULL;
> +	char *dev = NULL;
> +	const char *devname;
>   	int ret;
>   
>   	/* use malloc instead of rte_malloc as it's called early at init */
> @@ -94,34 +105,51 @@ rte_eal_devargs_add(enum rte_devtype devtype, const char *devargs_str)
>   	memset(devargs, 0, sizeof(*devargs));
>   	devargs->type = devtype;
>   
> -	if (rte_eal_parse_devargs_str(devargs_str, &buf, &devargs->args))
> +	if (rte_eal_parse_devargs_str(devargs_str, &dev, &devargs->args))

A very basic (and possibly incorrect) question:

here, for example "'net_pcap0,rx_pcap=input.pcap,tx_pcap=output.pcap'" 
was passed to application, which would mean;

dev = "net_pcap0" (name of the device)
devargs = "rx_pcap=input.pcap,tx_pcap=output.pcap"

>   		goto fail;
> +	devname = dev;
> +	do {
> +		bus = rte_bus_find(bus, bus_name_cmp, dev);
> +		if (bus == NULL)
> +			break;
> +		devname = dev + strlen(bus->name) + 1;

Assuming "vdev" bus:
                       "net_pcap0"
                             |
devname points here --------' (4+1) chars from start of "net_pcap0".
Is that the expectation?

Probably I am missing something here (maybe the input already has a bus 
name.)

Or, if this is not the case, then we will have to change the test 
application (test_devargs.c) which passes such strings to 
"rte_eal_devargs_add".

> +		if (rte_bus_find_by_device_name(devname) == bus)

Obviously, if my assumption is correct, this fails. Or, maybe I am 
completely off the mark.

> +			break;
> +		devname = dev;
> +	} while (1);
> +	if (bus == NULL) {
> +		bus = rte_bus_find_by_device_name(devname);
> +		if (bus == NULL) {
> +			fprintf(stderr, "ERROR: failed to parse bus info from device declaration\n");
> +			goto fail;
> +		}
> +	}
> +	devargs->bus = bus;
   >   	switch (devargs->type) {
>   	case RTE_DEVTYPE_WHITELISTED_PCI:
>   	case RTE_DEVTYPE_BLACKLISTED_PCI:
>   		/* try to parse pci identifier */
> -		if (eal_parse_pci_BDF(buf, &devargs->pci.addr) != 0 &&
> -		    eal_parse_pci_DomBDF(buf, &devargs->pci.addr) != 0)
> +		if (bus->parse(devname, &devargs->pci.addr) != 0)
>   			goto fail;
>   
>   		break;
>   	case RTE_DEVTYPE_VIRTUAL:
>   		/* save driver name */
>   		ret = snprintf(devargs->virt.drv_name,
> -			       sizeof(devargs->virt.drv_name), "%s", buf);
> +			       sizeof(devargs->virt.drv_name), "%s", devname);
>   		if (ret < 0 || ret >= (int)sizeof(devargs->virt.drv_name))
>   			goto fail;
>   
>   		break;
>   	}

I think all this will change in the devargs series.

>   
> -	free(buf);
> +	free(dev);
>   	TAILQ_INSERT_TAIL(&devargs_list, devargs, next);
>   	return 0;
>   
>   fail:
> -	free(buf);
> +	free(dev);
>   	if (devargs) {
>   		free(devargs->args);
>   		free(devargs);
> diff --git a/lib/librte_eal/common/eal_common_vdev.c b/lib/librte_eal/common/eal_common_vdev.c
> index 6ecd1b5..8fd1ef7 100644
> --- a/lib/librte_eal/common/eal_common_vdev.c
> +++ b/lib/librte_eal/common/eal_common_vdev.c
> @@ -177,6 +177,7 @@ alloc_devargs(const char *name, const char *args)
>   		return NULL;
>   
>   	devargs->type = RTE_DEVTYPE_VIRTUAL;
> +	devargs->bus = rte_bus_find_by_name("vdev");
>   	if (args)
>   		devargs->args = strdup(args);
>   
> @@ -289,12 +290,13 @@ vdev_scan(void)
>   {
>   	struct rte_vdev_device *dev;
>   	struct rte_devargs *devargs;
> +	struct rte_bus *vbus;
>   
>   	/* for virtual devices we scan the devargs_list populated via cmdline */
> -
> +	vbus = rte_bus_find_by_name("vdev");
>   	TAILQ_FOREACH(devargs, &devargs_list, next) {
>   
> -		if (devargs->type != RTE_DEVTYPE_VIRTUAL)
> +		if (devargs->bus != vbus)
>   			continue;
>   
>   		dev = find_vdev(devargs->virt.drv_name);
> diff --git a/lib/librte_eal/common/include/rte_devargs.h b/lib/librte_eal/common/include/rte_devargs.h
> index 88120a1..1f50a24 100644
> --- a/lib/librte_eal/common/include/rte_devargs.h
> +++ b/lib/librte_eal/common/include/rte_devargs.h
> @@ -51,6 +51,7 @@ extern "C" {
>   #include <stdio.h>
>   #include <sys/queue.h>
>   #include <rte_pci.h>
> +#include <rte_bus.h>
>   
>   /**
>    * Type of generic device
> @@ -89,6 +90,8 @@ struct rte_devargs {
>   			char drv_name[32];
>   		} virt;
>   	};
> +	/** Bus handle for the device. */
> +	struct rte_bus *bus;
>   	/** Arguments string as given by user or "" for no argument. */
>   	char *args;
>   };
> 
-
Shreyansh