[dpdk-dev] [PATCH V18 3/4] eal/linux: uevent parse and process

[Guo, Jia]

thanks for review.


On 4/4/2018 11:15 AM, Tan, Jianfeng wrote:
> Hi Jeff,
>
> Looks much better now, but still have some issues to address.
>
>> -----Original Message-----
>> From: Guo, Jia
>> Sent: Tuesday, April 3, 2018 6:34 PM
>> To: stephen at networkplumber.org; Richardson, Bruce; Yigit, Ferruh;
>> Ananyev, Konstantin; gaetan.rivet at 6wind.com; Wu, Jingjing;
>> thomas at monjalon.net; motih at mellanox.com; Van Haaren, Harry; Tan,
>> Jianfeng
>> Cc: jblunck at infradead.org; shreyansh.jain at nxp.com; dev at dpdk.org; Guo,
>> Jia; Zhang, Helin
>> Subject: [PATCH V18 3/4] eal/linux: uevent parse and process
>>
>> In order to handle the uevent which has been detected from the kernel
>> side, add uevent parse and process function to translate the uevent into
>> device event, which user has subscribed to monitor.
>>
>> Signed-off-by: Jeff Guo <jia.guo at intel.com>
>> ---
>> v18->v17:
>> refine socket configuration.
>> ---
>>   lib/librte_eal/linuxapp/eal/eal_dev.c | 178
>> +++++++++++++++++++++++++++++++++-
>>   1 file changed, 176 insertions(+), 2 deletions(-)
>>
>> diff --git a/lib/librte_eal/linuxapp/eal/eal_dev.c
>> b/lib/librte_eal/linuxapp/eal/eal_dev.c
>> index 9c8d1a0..9f2ee40 100644
>> --- a/lib/librte_eal/linuxapp/eal/eal_dev.c
>> +++ b/lib/librte_eal/linuxapp/eal/eal_dev.c
>> @@ -2,21 +2,195 @@
>>    * Copyright(c) 2018 Intel Corporation
>>    */
>>
>> +#include <string.h>
>> +#include <unistd.h>
>> +#include <sys/socket.h>
>> +#include <linux/netlink.h>
>> +
>>   #include <rte_log.h>
>>   #include <rte_compat.h>
>>   #include <rte_dev.h>
>> +#include <rte_malloc.h>
>> +#include <rte_interrupts.h>
>> +
>> +#include "eal_private.h"
>> +
>> +static struct rte_intr_handle intr_handle = {.fd = -1 };
>> +static bool monitor_started;
>> +
>> +#define EAL_UEV_MSG_LEN 4096
>> +#define EAL_UEV_MSG_ELEM_LEN 128
>> +
>> +/* identify the system layer which event exposure from */
> Reword it a little bit:
>      /* identify the system layer which reports this event */
>
>> +enum eal_dev_event_subsystem {
>> +	EAL_DEV_EVENT_SUBSYSTEM_PCI, /* PCI bus device event */
>> +	EAL_DEV_EVENT_SUBSYSTEM_UIO, /* UIO driver device event */
>> +	EAL_DEV_EVENT_SUBSYSTEM_VFIO, /* VFIO driver device event */
>> +	EAL_DEV_EVENT_SUBSYSTEM_MAX
>> +};
>> +
>> +static int
>> +dev_uev_socket_fd_create(void)
>> +{
>> +	struct sockaddr_nl addr;
>> +	int ret;
>> +
>> +	intr_handle.fd = socket(PF_NETLINK, SOCK_RAW | SOCK_CLOEXEC |
>> +			SOCK_NONBLOCK,
>> +			NETLINK_KOBJECT_UEVENT);
>> +	if (intr_handle.fd < 0) {
>> +		RTE_LOG(ERR, EAL, "create uevent fd failed.\n");
>> +		return -1;
>> +	}
>> +
>> +	memset(&addr, 0, sizeof(addr));
>> +	addr.nl_family = AF_NETLINK;
>> +	addr.nl_pid = 0;
>> +	addr.nl_groups = 0xffffffff;
>> +
>> +	ret = bind(intr_handle.fd, (struct sockaddr *) &addr, sizeof(addr));
>> +	if (ret < 0) {
>> +		RTE_LOG(ERR, EAL, "Failed to bind socket for netlink fd.\n");
> Reword it a little bit so that we can understand it's a log related to hotplug:
>      Failed to bind uevent socket
>
>> +		goto err;
>> +	}
>> +
>> +	return 0;
>> +err:
>> +	close(intr_handle.fd);
> Then: intr_handle.fd = -1?
sure.
>> +	return ret;
>> +}
>> +
>> +static void
>> +dev_uev_parse(const char *buf, struct rte_dev_event *event, int length)
>> +{
>> +	char action[EAL_UEV_MSG_ELEM_LEN];
>> +	char subsystem[EAL_UEV_MSG_ELEM_LEN];
>> +	char pci_slot_name[EAL_UEV_MSG_ELEM_LEN];
>> +	int i = 0;
>> +
>> +	memset(action, 0, EAL_UEV_MSG_ELEM_LEN);
>> +	memset(subsystem, 0, EAL_UEV_MSG_ELEM_LEN);
>> +	memset(pci_slot_name, 0, EAL_UEV_MSG_ELEM_LEN);
>> +
>> +	while (i < length) {
>> +		for (; i < length; i++) {
>> +			if (*buf)
>> +				break;
>> +			buf++;
>> +		}
>> +		if (!strncmp(buf, "ACTION=", 7)) {
>> +			buf += 7;
>> +			i += 7;
>> +			snprintf(action, sizeof(action), "%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);
>> +			event->devname = strdup(pci_slot_name);
>> +		}
>> +		for (; i < length; i++) {
>> +			if (*buf == '\0')
>> +				break;
>> +			buf++;
>> +		}
>> +	}
>> +
>> +	if (!strncmp(subsystem, "uio", 3))
>> +		event->subsystem = EAL_DEV_EVENT_SUBSYSTEM_UIO;
>> +	else if (!strncmp(subsystem, "pci", 3))
>> +		event->subsystem = EAL_DEV_EVENT_SUBSYSTEM_PCI;
>> +	else if (!strncmp(subsystem, "vfio", 4))
> How can we indicate it is an event with subsystem that we will not handle?
>
>> +		event->subsystem = EAL_DEV_EVENT_SUBSYSTEM_VFIO;
>> +	if (!strncmp(action, "add", 3))
>> +		event->type = RTE_DEV_EVENT_ADD;
>> +	if (!strncmp(action, "remove", 6))
>> +		event->type = RTE_DEV_EVENT_REMOVE;
> How can we indicate it is an event with type that we will not handle?
>
> My suggestion is to define a return value for that:
> - EVENT_VALID returned for an event that we will handle later.
> - EVENT_INVALID returned for any unknown events.
make sense ,just need 0 & -1 enough i think.
>> +}
>> +
>> +static int
>> +dev_uev_receive(int fd, struct rte_dev_event *uevent)
>> +{
>> +	int ret;
>> +	char buf[EAL_UEV_MSG_LEN];
>> +
>> +	memset(uevent, 0, sizeof(struct rte_dev_event));
>> +	memset(buf, 0, EAL_UEV_MSG_LEN);
>> +
>> +	ret = recv(fd, buf, EAL_UEV_MSG_LEN, MSG_DONTWAIT);
>> +	if (ret < 0) {
>> +		RTE_LOG(ERR, EAL,
>> +			"Socket read error(%d): %s.\n",
>> +			errno, strerror(errno));
>> +		return -1;
>> +	} else if (ret == 0)
>> +		/* connection closed */
>> +		return -1;
>> +
>> +	dev_uev_parse(buf, uevent, EAL_UEV_MSG_LEN);
>> +
>> +	return 0;
>> +}
>> +
>> +static void
>> +dev_uev_process(__rte_unused void *param)
>> +{
>> +	struct rte_dev_event uevent;
>> +
>> +	if (dev_uev_receive(intr_handle.fd, &uevent))
> If error happens, we shall start an alarm task to remove the callback of interrupt thread.
>> +		return;
> You may want to add a log here for debugging, showing what event comes for which device.
>
>> +	if (uevent.devname)
> You can also filter this kind of events using the way I suggested above.
>
>> +		dev_callback_process(uevent.devname, uevent.type);
>> +}
>>
>>   int __rte_experimental
>>   rte_dev_event_monitor_start(void)
>>   {
>> -	/* TODO: start uevent monitor for linux */
>> +	int ret;
>> +
>> +	if (monitor_started)
>> +		return 0;
>> +
>> +	ret = dev_uev_socket_fd_create();
>> +	if (ret) {
>> +		RTE_LOG(ERR, EAL, "error create device event fd.\n");
>> +		return -1;
>> +	}
>> +
>> +	intr_handle.type = RTE_INTR_HANDLE_DEV_EVENT;
>> +	ret = rte_intr_callback_register(&intr_handle, dev_uev_process,
>> NULL);
>> +
>> +	if (ret) {
>> +		RTE_LOG(ERR, EAL, "fail to register uevent callback.\n");
>> +		return -1;
>> +	}
>> +
>> +	monitor_started = true;
>> +
>>   	return 0;
>>   }
>>
>>   int __rte_experimental
>>   rte_dev_event_monitor_stop(void)
>>   {
>> -	/* TODO: stop uevent monitor for linux */
>> +	int ret;
>> +
>> +	if (!monitor_started)
>> +		return 0;
>> +
>> +	ret = rte_intr_callback_unregister(&intr_handle, dev_uev_process,
>> +					   (void *)-1);
>> +	if (ret < 0) {
>> +		RTE_LOG(ERR, EAL, "fail to unregister uevent callback.\n");
>> +		return ret;
>> +	}
>> +
>> +	close(intr_handle.fd);
>> +	intr_handle.fd = -1;
>> +	monitor_started = false;
>>   	return 0;
>>   }
>> --
>> 2.7.4