NAME

       ibv_get_async_event, ibv_ack_async_event - get or acknowledge asynchronous events

SYNOPSIS

       #include <infiniband/verbs.h>

       int ibv_get_async_event(struct ibv_context *context,
                               struct ibv_async_event *event);

       void ibv_ack_async_event(struct ibv_async_event *event);

DESCRIPTION

       ibv_get_async_event()  waits  for  the next async event of the RDMA device context context
       and returns it through the pointer event, which is an ibv_async_event struct,  as  defined
       in <infiniband/verbs.h>.

       struct ibv_async_event {
               union {
                       struct ibv_cq  *cq;             /* CQ that got the event */
                       struct ibv_qp  *qp;             /* QP that got the event */
                       struct ibv_srq *srq;            /* SRQ that got the event */
                       struct ibv_wq  *wq;             /* WQ that got the event */
                       int             port_num;       /* port number that got the event */
               } element;
               enum ibv_event_type     event_type;     /* type of the event */
       };

       One  member  of the element union will be valid, depending on the event_type member of the
       structure.  event_type will be one of the following events:

       QP events:

       IBV_EVENT_QP_FATAL  Error occurred on a QP and it transitioned to error state

       IBV_EVENT_QP_REQ_ERR  Invalid Request Local Work Queue Error

       IBV_EVENT_QP_ACCESS_ERR  Local access violation error

       IBV_EVENT_COMM_EST  Communication was established on a QP

       IBV_EVENT_SQ_DRAINED  Send Queue was drained of outstanding messages in progress

       IBV_EVENT_PATH_MIG  A connection has migrated to the alternate path

       IBV_EVENT_PATH_MIG_ERR  A connection failed to migrate to the alternate path

       IBV_EVENT_QP_LAST_WQE_REACHED  Last WQE Reached on a QP associated with an SRQ

       CQ events:

       IBV_EVENT_CQ_ERR  CQ is in error (CQ overrun)

       SRQ events:

       IBV_EVENT_SRQ_ERR  Error occurred on an SRQ

       IBV_EVENT_SRQ_LIMIT_REACHED  SRQ limit was reached

       WQ events:

       IBV_EVENT_WQ_FATAL  Error occurred on a WQ and it transitioned to error state

       Port events:

       IBV_EVENT_PORT_ACTIVE  Link became active on a port

       IBV_EVENT_PORT_ERR  Link became unavailable on a port

       IBV_EVENT_LID_CHANGE  LID was changed on a port

       IBV_EVENT_PKEY_CHANGE  P_Key table was changed on a port

       IBV_EVENT_SM_CHANGE  SM was changed on a port

       IBV_EVENT_CLIENT_REREGISTER  SM sent a CLIENT_REREGISTER request to a port

       IBV_EVENT_GID_CHANGE  GID table was changed on a port

       CA events:

       IBV_EVENT_DEVICE_FATAL  CA is in FATAL state

       ibv_ack_async_event() acknowledge the async event event.

RETURN VALUE

       ibv_get_async_event() returns 0 on success, and -1 on error.

       ibv_ack_async_event() returns no value.

NOTES

       All  async  events  that  ibv_get_async_event()  returns  must   be   acknowledged   using
       ibv_ack_async_event().  To avoid races, destroying an object (CQ, SRQ or QP) will wait for
       all affiliated events for the object  to  be  acknowledged;  this  avoids  an  application
       retrieving an affiliated event after the corresponding object has already been destroyed.

       ibv_get_async_event()  is  a  blocking  function.   If multiple threads call this function
       simultaneously, then when an async event occurs, only one thread will receive it,  and  it
       is not possible to predict which thread will receive it.

EXAMPLES

       The following code example demonstrates one possible way to work with async events in non-
       blocking mode.  It performs the following steps:

       1. Set the async events queue work mode to be non-blocked
       2. Poll the queue until it has an async event
       3. Get the async event and ack it

       /* change the blocking mode of the async event queue */
       flags = fcntl(ctx->async_fd, F_GETFL);
       rc = fcntl(ctx->async_fd, F_SETFL, flags | O_NONBLOCK);
       if (rc < 0) {
               fprintf(stderr, "Failed to change file descriptor of async event queue\n");
               return 1;
       }

       /*
        * poll the queue until it has an event and sleep ms_timeout
        * milliseconds between any iteration
        */
       my_pollfd.fd      = ctx->async_fd;
       my_pollfd.events  = POLLIN;
       my_pollfd.revents = 0;

       do {
               rc = poll(&my_pollfd, 1, ms_timeout);
       } while (rc == 0);
       if (rc < 0) {
               fprintf(stderr, "poll failed\n");
               return 1;
       }

       /* Get the async event */
       if (ibv_get_async_event(ctx, &async_event)) {
               fprintf(stderr, "Failed to get async_event\n");
               return 1;
       }

       /* Ack the event */
       ibv_ack_async_event(&async_event);

SEE ALSO

       ibv_open_device(3)

AUTHORS

       Dotan Barak <dotanba@gmail.com>