eal/linux: add epoll wrappers

[dpdk.git] / lib / librte_eal / linuxapp / eal / eal_interrupts.c

diff --git a/lib/librte_eal/linuxapp/eal/eal_interrupts.c b/lib/librte_eal/linuxapp/eal/eal_interrupts.c
index 61e7c85..55be263 100644 (file)
--- a/lib/librte_eal/linuxapp/eal/eal_interrupts.c
+++ b/lib/librte_eal/linuxapp/eal/eal_interrupts.c
@@ -69,6 +69,8 @@
 
 #define EAL_INTR_EPOLL_WAIT_FOREVER (-1)
 
+static RTE_DEFINE_PER_LCORE(int, _epfd) = -1; /**< epoll fd per thread */
+
 /**
  * union for pipe fds.
  */
@@ -896,3 +898,140 @@ rte_eal_intr_init(void)
 
        return -ret;
 }
+
+static int
+eal_epoll_process_event(struct epoll_event *evs, unsigned int n,
+                       struct rte_epoll_event *events)
+{
+       unsigned int i, count = 0;
+       struct rte_epoll_event *rev;
+
+       for (i = 0; i < n; i++) {
+               rev = evs[i].data.ptr;
+               if (!rev || !rte_atomic32_cmpset(&rev->status, RTE_EPOLL_VALID,
+                                                RTE_EPOLL_EXEC))
+                       continue;
+
+               events[count].status        = RTE_EPOLL_VALID;
+               events[count].fd            = rev->fd;
+               events[count].epfd          = rev->epfd;
+               events[count].epdata.event  = rev->epdata.event;
+               events[count].epdata.data   = rev->epdata.data;
+               if (rev->epdata.cb_fun)
+                       rev->epdata.cb_fun(rev->fd,
+                                          rev->epdata.cb_arg);
+
+               rte_compiler_barrier();
+               rev->status = RTE_EPOLL_VALID;
+               count++;
+       }
+       return count;
+}
+
+static inline int
+eal_init_tls_epfd(void)
+{
+       int pfd = epoll_create(255);
+
+       if (pfd < 0) {
+               RTE_LOG(ERR, EAL,
+                       "Cannot create epoll instance\n");
+               return -1;
+       }
+       return pfd;
+}
+
+int
+rte_intr_tls_epfd(void)
+{
+       if (RTE_PER_LCORE(_epfd) == -1)
+               RTE_PER_LCORE(_epfd) = eal_init_tls_epfd();
+
+       return RTE_PER_LCORE(_epfd);
+}
+
+int
+rte_epoll_wait(int epfd, struct rte_epoll_event *events,
+              int maxevents, int timeout)
+{
+       struct epoll_event evs[maxevents];
+       int rc;
+
+       if (!events) {
+               RTE_LOG(ERR, EAL, "rte_epoll_event can't be NULL\n");
+               return -1;
+       }
+
+       /* using per thread epoll fd */
+       if (epfd == RTE_EPOLL_PER_THREAD)
+               epfd = rte_intr_tls_epfd();
+
+       while (1) {
+               rc = epoll_wait(epfd, evs, maxevents, timeout);
+               if (likely(rc > 0)) {
+                       /* epoll_wait has at least one fd ready to read */
+                       rc = eal_epoll_process_event(evs, rc, events);
+                       break;
+               } else if (rc < 0) {
+                       if (errno == EINTR)
+                               continue;
+                       /* epoll_wait fail */
+                       RTE_LOG(ERR, EAL, "epoll_wait returns with fail %s\n",
+                               strerror(errno));
+                       rc = -1;
+                       break;
+               }
+       }
+
+       return rc;
+}
+
+static inline void
+eal_epoll_data_safe_free(struct rte_epoll_event *ev)
+{
+       while (!rte_atomic32_cmpset(&ev->status, RTE_EPOLL_VALID,
+                                   RTE_EPOLL_INVALID))
+               while (ev->status != RTE_EPOLL_VALID)
+                       rte_pause();
+       memset(&ev->epdata, 0, sizeof(ev->epdata));
+       ev->fd = -1;
+       ev->epfd = -1;
+}
+
+int
+rte_epoll_ctl(int epfd, int op, int fd,
+             struct rte_epoll_event *event)
+{
+       struct epoll_event ev;
+
+       if (!event) {
+               RTE_LOG(ERR, EAL, "rte_epoll_event can't be NULL\n");
+               return -1;
+       }
+
+       /* using per thread epoll fd */
+       if (epfd == RTE_EPOLL_PER_THREAD)
+               epfd = rte_intr_tls_epfd();
+
+       if (op == EPOLL_CTL_ADD) {
+               event->status = RTE_EPOLL_VALID;
+               event->fd = fd;  /* ignore fd in event */
+               event->epfd = epfd;
+               ev.data.ptr = (void *)event;
+       }
+
+       ev.events = event->epdata.event;
+       if (epoll_ctl(epfd, op, fd, &ev) < 0) {
+               RTE_LOG(ERR, EAL, "Error op %d fd %d epoll_ctl, %s\n",
+                       op, fd, strerror(errno));
+               if (op == EPOLL_CTL_ADD)
+                       /* rollback status when CTL_ADD fail */
+                       event->status = RTE_EPOLL_INVALID;
+               return -1;
+       }
+
+       if (op == EPOLL_CTL_DEL && event->status != RTE_EPOLL_INVALID)
+               eal_epoll_data_safe_free(event);
+
+       return 0;
+}