[dpdk-dev] [PATCH v6 1/2] eal: add uevent monitor for hot plug

[Guo, Jia]

On 12/26/2017 2:06 AM, Stephen Hemminger wrote:
> On Thu,  2 Nov 2017 04:16:44 +0800
> Jeff Guo <jia.guo at intel.com> wrote:
>
>> +int
>> +rte_dev_bind_driver(const char *dev_name, const char *drv_type) {
> Bracket left after declaration.
thanks.
>
>
>> +	snprintf(drv_override_path, sizeof(drv_override_path),
>> +		"/sys/bus/pci/devices/%s/driver_override", dev_name);
>> +
>> +	/* specify the driver for a device by writing to driver_override */
>> +	drv_override_fd = open(drv_override_path, O_WRONLY);
>> +	if (drv_override_fd < 0) {
>> +		RTE_LOG(ERR, EAL, "Cannot open %s: %s\n",
>> +			drv_override_path, strerror(errno));
>> +		goto err;
>> +	}
>
> You should not have dev functions that assume PCI. Please split into common
> and bus specific code.
>
>
make sense, will modify it into bus specific code.
>> +static int
>> +dev_uev_parse(const char *buf, struct rte_eal_uevent *event)
>> +{
>> +	char action[RTE_EAL_UEVENT_MSG_LEN];
>> +	char subsystem[RTE_EAL_UEVENT_MSG_LEN];
>> +	char dev_path[RTE_EAL_UEVENT_MSG_LEN];
>> +	char pci_slot_name[RTE_EAL_UEVENT_MSG_LEN];
>> +	int i = 0;
>> +
>> +	memset(action, 0, RTE_EAL_UEVENT_MSG_LEN);
>> +	memset(subsystem, 0, RTE_EAL_UEVENT_MSG_LEN);
>> +	memset(dev_path, 0, RTE_EAL_UEVENT_MSG_LEN);
>> +	memset(pci_slot_name, 0, RTE_EAL_UEVENT_MSG_LEN);
>> +
>> +	while (i < RTE_EAL_UEVENT_MSG_LEN) {
>> +		for (; i < RTE_EAL_UEVENT_MSG_LEN; i++) {
>> +			if (*buf)
>> +				break;
>> +			buf++;
>> +		}
>> +		if (!strncmp(buf, "libudev", 7)) {
>> +			buf += 7;
>> +			i += 7;
>> +			event->group = UEV_MONITOR_UDEV;
>> +		}
>> +		if (!strncmp(buf, "ACTION=", 7)) {
>> +			buf += 7;
>> +			i += 7;
>> +			snprintf(action, sizeof(action), "%s", buf);
> Why snprintf rather than strncpy?
>
snprintf would no need manual write '\0' and the src length is not 
explicit, and if concern about the efficiency of the snprintf scan, i 
will constrain the value of dest buf length.
>> +		} else if (!strncmp(buf, "DEVPATH=", 8)) {
>> +			buf += 8;
>> +			i += 8;
>> +			snprintf(dev_path, sizeof(dev_path), "%s", buf);
>> +		} else if (!strncmp(buf, "SUBSYSTEM=", 10)) {
>> +			buf += 10;
>> +			i += 10;
>> +			snprintf(subsystem, sizeof(subsystem), "%s", buf);
>> +		} else if (!strncmp(buf, "PCI_SLOT_NAME=", 14)) {
>> +			buf += 14;
>> +			i += 14;
>> +			snprintf(pci_slot_name, sizeof(subsystem), "%s", buf);
>> +		}
>> +		for (; i < RTE_EAL_UEVENT_MSG_LEN; i++) {
>> +			if (*buf == '\0')
>> +				break;
>> +			buf++;
>> +		}
>> +	}
>> +
>> +	if (!strncmp(subsystem, "pci", 3))
>> +		event->subsystem = UEV_SUBSYSTEM_PCI;
>> +	if (!strncmp(action, "add", 3))
>> +		event->type = RTE_EAL_DEV_EVENT_ADD;
>> +	if (!strncmp(action, "remove", 6))
>> +		event->type = RTE_EAL_DEV_EVENT_REMOVE;
>> +	event->devname = pci_slot_name;
> Why do you need to first capture the strings, then set state variables?
> Instead why not update event->xxx directly?
i think that would be more benefit to read and manage out of the loop.