[dpdk-dev] [PATCH V19 3/4] eal/linux: uevent parse and process

[Tan, Jianfeng]

On 4/5/2018 5:02 PM, Jeff Guo wrote:
> 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>
> ---
> v19->18:
> fix some misunderstanding part
> ---
>   lib/librte_eal/linuxapp/eal/eal_dev.c | 196 +++++++++++++++++++++++++++++++++-
>   1 file changed, 194 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..4686c41 100644
> --- a/lib/librte_eal/linuxapp/eal/eal_dev.c
> +++ b/lib/librte_eal/linuxapp/eal/eal_dev.c
> @@ -2,21 +2,213 @@
>    * 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 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 uevent socket.\n");
> +		goto err;
> +	}
> +
> +	return 0;
> +err:
> +	close(intr_handle.fd);
> +	intr_handle.fd = -1;
> +	return ret;
> +}
> +
> +static int
> +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, ret = 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++;
> +		}
> +		/**
> +		 * check device uevent from kernel side, no need to check
> +		 * uevent from udev.
> +		 */
> +		if (!strncmp(buf, "libudev", 7)) {
> +			buf += 7;
> +			i += 7;
> +			return -1;
> +		}
> +		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++;
> +		}
> +	}
> +
> +	/* parse the subsystem layer */
> +	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))
> +		event->subsystem = EAL_DEV_EVENT_SUBSYSTEM_VFIO;
> +	else
> +		ret = -1;

We can just return -1 here.

>   
> +	/* parse the action type */
> +	if (!strncmp(action, "add", 3))
> +		event->type = RTE_DEV_EVENT_ADD;
> +	else if (!strncmp(action, "remove", 6))
> +		event->type = RTE_DEV_EVENT_REMOVE;
> +	else
> +		ret = -1;

We can just return -1 here.

> +	return ret;

return 0 here.

> +}
> +
> +static void
> +dev_uev_handler(__rte_unused void *param)
> +{
> +	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(intr_handle.fd, buf, EAL_UEV_MSG_LEN, MSG_DONTWAIT);
> +	if (ret == 0 || (ret < 0 && errno != EAGAIN)) {
> +		/* connection is closed or broken, can not up again. */
> +		RTE_LOG(ERR, EAL, "uevent socket connection is broken.\n");

Again, we need an alarm to unregister the callback from intr thread.

> +		return;
> +	} else if (ret < 0) {
> +		RTE_LOG(ERR, EAL,
> +			"uevent socket read error(%d): %s.\n",
> +			errno, strerror(errno));
> +		return;
> +	}

I think the above code can be adjusted as:

     if (ret == 0 || (ret < 0 && errno == EAGAIN))
             return;
     else if (ret < 0) {
            RTE_LOG(ERR, EAL, "...");
            set_alarm_to_unregister();
     }


> +
> +	ret = dev_uev_parse(buf, &uevent, EAL_UEV_MSG_LEN);
> +	if (ret < 0) {
> +		RTE_LOG(ERR, EAL, "It is not an valid event "

s/ERR/DEBUG, or there are too many logs.

> +			"that need to be handle.\n");
> +		return;
> +	}
> +
> +	RTE_LOG(DEBUG, EAL, "receive uevent(name:%s, type:%d, subsystem:%d)\n",
> +		uevent.devname, uevent.type, uevent.subsystem);
> +
> +	if (uevent.devname)
> +		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_handler, 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_handler,
> +					   (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;
>   }