[dpdk-dev] [PATCH V16 3/4] eal/linux: uevent parse and process

[Guo, Jia]

jianfeng


On 3/29/2018 12:15 AM, Tan, Jianfeng wrote:
> BTW, adding new .c file needs to update meson.build now.
>
thanks for your info .
> On 3/26/2018 7:20 PM, Jeff Guo wrote:
>> In order to handle the uevent which have been detected from the kernel
>> side, add uevent parse and process function to translate the uevent into
>> device event, which user has subscribe to monitor.
>>
>> Signed-off-by: Jeff Guo <jia.guo at intel.com>
>> ---
>> 1.move all linux specific together
>> ---
>>   lib/librte_eal/linuxapp/eal/eal_dev.c | 214 
>> +++++++++++++++++++++++++++++++++-
>>   1 file changed, 211 insertions(+), 3 deletions(-)
>>
>> diff --git a/lib/librte_eal/linuxapp/eal/eal_dev.c 
>> b/lib/librte_eal/linuxapp/eal/eal_dev.c
>> index 5ab5830..90094c0 100644
>> --- a/lib/librte_eal/linuxapp/eal/eal_dev.c
>> +++ b/lib/librte_eal/linuxapp/eal/eal_dev.c
>> @@ -2,19 +2,227 @@
>>    * Copyright(c) 2018 Intel Corporation
>>    */
>>   -#include <rte_log.h>
>> +#include <stdio.h>
>> +#include <string.h>
>> +#include <inttypes.h>
>> +#include <sys/queue.h>
>> +#include <sys/signalfd.h>
>> +#include <sys/ioctl.h>
>> +#include <sys/socket.h>
>> +#include <linux/netlink.h>
>> +#include <sys/epoll.h>
>> +#include <unistd.h>
>> +#include <signal.h>
>
> Some header files are not necessary, the above one for example.
>
>> +#include <stdbool.h>
>> +#include <fcntl.h>
>> +
>> +#include <rte_malloc.h>
>> +#include <rte_bus.h>
>>   #include <rte_dev.h>
>> +#include <rte_devargs.h>
>
> We don't need this one neither.
>
>> +#include <rte_debug.h>
>> +#include <rte_log.h>
>> +#include <rte_interrupts.h>
>> +
>> +#include "eal_private.h"
>> +#include "eal_thread.h"
>
> Ditto.
>
>> +
>> +static struct rte_intr_handle intr_handle = {.fd = -1 };
>
> I don't think we need a static intr_handle, what we need is the 
> monitor fd.
>
>> +static bool monitor_not_started = true;
>> +
>> +#define EAL_UEV_MSG_LEN 4096
>> +#define EAL_UEV_MSG_ELEM_LEN 128
>> +
>> +/* identify the system layer which event exposure from */
>> +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_MAX
>> +};
>> +
>> +static int
>> +dev_uev_monitor_fd_new(void)
>> +{
>> +    int uevent_fd;
>> +
>> +    uevent_fd = socket(PF_NETLINK, SOCK_RAW | SOCK_CLOEXEC |
>> +            SOCK_NONBLOCK,
>> +            NETLINK_KOBJECT_UEVENT);
>> +    if (uevent_fd < 0) {
>> +        RTE_LOG(ERR, EAL, "create uevent fd failed\n");
>> +        return -1;
>> +    }
>> +    return uevent_fd;
>> +}
>> +
>> +static int
>> +dev_uev_monitor_create(int netlink_fd)
>
> I think we should merge this function with above function. I don't see 
> a reason to split into two functions.
>
make sense.
>> +{
>> +    struct sockaddr_nl addr;
>> +    int ret;
>> +    int size = 64 * 1024;
>> +    int nonblock = 1;
>> +
>> +    memset(&addr, 0, sizeof(addr));
>> +    addr.nl_family = AF_NETLINK;
>> +    addr.nl_pid = 0;
>> +    addr.nl_groups = 0xffffffff;
>> +
>> +    if (bind(netlink_fd, (struct sockaddr *) &addr, sizeof(addr)) < 
>> 0) {
>> +        RTE_LOG(ERR, EAL, "bind failed\n");
>
> Please print more information here, so that we don't have to check the 
> code if we really encounter such an error.
>
>> +        goto err;
>> +    }
>> +
>> +    setsockopt(netlink_fd, SOL_SOCKET, SO_PASSCRED, &size, 
>> sizeof(size));
>> +
>> +    ret = ioctl(netlink_fd, FIONBIO, &nonblock);
>> +    if (ret != 0) {
>> +        RTE_LOG(ERR, EAL, "ioctl(FIONBIO) failed\n");
>> +        goto err;
>> +    }
>> +    return 0;
>> +err:
>> +    close(netlink_fd);
>> +    return -1;
>> +}
>> +
>> +static void
>> +dev_uev_parse(const char *buf, struct rte_dev_event *event, int length)
>
> We always get an event we care? If no, we need return something so 
> that the caller can skip this event.
>
this function do no filter the event.
>> +{
>> +    char action[EAL_UEV_MSG_ELEM_LEN];
>> +    char subsystem[EAL_UEV_MSG_ELEM_LEN];
>> +    char dev_path[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(dev_path, 0, EAL_UEV_MSG_ELEM_LEN);
>> +    memset(pci_slot_name, 0, EAL_UEV_MSG_ELEM_LEN);
>
> I did not see you need dev_path, why do we care to parse it?
>
>> +
>> +    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, "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);
>> +            event->devname = pci_slot_name;
>
> You are assigning a stack pointer for the caller to use; this is 
> dangerous, we should never do that.
>
make sense.
>> +        }
>> +        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;
>> +    if (!strncmp(action, "add", 3))
>> +        event->type = RTE_DEV_EVENT_ADD;
>> +    if (!strncmp(action, "remove", 6))
>> +        event->type = RTE_DEV_EVENT_REMOVE;
>> +}
>> +
>> +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));
>
> The above three lines are in bad format.
>
>> +        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))
>> +        return;
>> +
>> +    if (uevent.devname)
>> +        dev_callback_process(uevent.devname, uevent.type, NULL);
>> +}
>>     int __rte_experimental
>>   rte_dev_event_monitor_start(void)
>>   {
>> -    /* TODO: start uevent monitor for linux */
>> +    int ret;
>> +
>> +    if (!monitor_not_started)
>> +        return 0;
>> +
>> +    intr_handle.fd = dev_uev_monitor_fd_new();
>> +    intr_handle.type = RTE_INTR_HANDLE_DEV_EVENT;
>> +
>> +    ret = dev_uev_monitor_create(intr_handle.fd);
>> +
>> +    if (ret) {
>> +        RTE_LOG(ERR, EAL, "error create device event monitor\n");
>> +        return -1;
>> +    }
>> +
>> +    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_not_started = false;
>> +
>>       return 0;
>>   }
>>     int __rte_experimental
>>   rte_dev_event_monitor_stop(void)
>>   {
>> -    /* TODO: stop uevent monitor for linux */
>> +    int ret;
>> +
>> +    if (monitor_not_started)
>> +        return 0;
>> +
>> +    ret = rte_intr_callback_unregister(&intr_handle, 
>> dev_uev_process, NULL);
>> +    if (ret) {
>> +        RTE_LOG(ERR, EAL, "fail to unregister uevent callback");
>> +        return ret;
>> +    }
>> +
>> +    close(intr_handle.fd);
>> +    intr_handle.fd = -1;
>> +    monitor_not_started = true;
>>       return 0;
>>   }
>