--- libev/ev_iouring.c	2019/12/27 21:56:29	1.11
+++ libev/ev_iouring.c	2019/12/28 03:29:50	1.13
@@ -89,6 +89,7 @@
 #include <sys/timerfd.h>
 #include <sys/mman.h>
 #include <poll.h>
+#include <stdint.h>
 
 #define IOURING_INIT_ENTRIES 32
 
@@ -175,8 +176,21 @@
   struct io_cqring_offsets cq_off;
 };
 
-#define IORING_OP_POLL_ADD    6
-#define IORING_OP_POLL_REMOVE 7
+#define IORING_SETUP_CQSIZE 0x00000008
+
+#define IORING_OP_POLL_ADD        6
+#define IORING_OP_POLL_REMOVE     7
+#define IORING_OP_TIMEOUT        11
+#define IORING_OP_TIMEOUT_REMOVE 12
+
+/* relative or absolute, reference clock is CLOCK_MONOTONIC */
+struct iouring_kernel_timespec
+{
+  int64_t tv_sec;
+  long long tv_nsec;
+};
+
+#define IORING_TIMEOUT_ABS 0x00000001
 
 #define IORING_ENTER_GETEVENTS 0x01
 
@@ -184,9 +198,9 @@
 #define IORING_OFF_CQ_RING 0x08000000ULL
 #define IORING_OFF_SQES	   0x10000000ULL
 
-#define IORING_FEAT_SINGLE_MMAP   0x1
-#define IORING_FEAT_NODROP        0x2
-#define IORING_FEAT_SUBMIT_STABLE 0x4
+#define IORING_FEAT_SINGLE_MMAP   0x00000001
+#define IORING_FEAT_NODROP        0x00000002
+#define IORING_FEAT_SUBMIT_STABLE 0x00000004
 
 inline_size
 int
@@ -291,6 +305,9 @@
   iouring_cq_ring = MAP_FAILED;
   iouring_sqes    = MAP_FAILED;
 
+  if (!have_monotonic) /* cannot really happen, but what if11 */
+    return -1;
+
   for (;;)
     {
       iouring_fd = evsys_io_uring_setup (iouring_entries, &params);
@@ -385,7 +402,12 @@
       struct io_uring_sqe *sqe = iouring_sqe_get (EV_A);
       sqe->opcode    = IORING_OP_POLL_REMOVE;
       sqe->fd        = fd;
-      sqe->user_data = -1;
+      /* Jens Axboe notified me that user_data is not what is documented, but is
+       * some kind of unique ID that has to match, otherwise the request cannot
+       * be removed. Since we don't *really* have that, we pass in the old
+       * generation counter - if that fails, too bad, it will hopefully be removed
+       * at close time and then be ignored. */
+      sqe->user_data = (uint32_t)fd | ((__u64)(uint32_t)anfds [fd].egen << 32);
       iouring_sqe_submit (EV_A_ sqe);
 
       /* increment generation counter to avoid handling old events */
@@ -436,11 +458,6 @@
   uint32_t gen = cqe->user_data >> 32;
   int      res = cqe->res;
 
-  /* ignore fd removal events, if there are any. TODO: verify */
-  /* TODO: yes, this triggers */
-  if (cqe->user_data == (__u64)-1)
-    return;
-
   assert (("libev: io_uring fd must be in-bounds", fd >= 0 && fd < anfdmax));
 
   /* documentation lies, of course. the result value is NOT like
@@ -450,6 +467,7 @@
    */
 
   /* ignore event if generation doesn't match */
+  /* other than skipping removal events, */
   /* this should actually be very rare */
   if (ecb_expect_false (gen != (uint32_t)anfds [fd].egen))
     return;