io_uring_peek_cqe and EAGAIN

[William Dauchy <wdauchy@gmail.com>]

Hello,

While doing some tests which are open/read/close files I saw that I
was getting -EAGAIN return value sometimesi on io_uring_peek_cqe,
and more often after dropping caches.
In parrallel, when reading examples provided by liburing, we can see
that getting this error is making the example fail (such as in
io_uring-cp). So I was wondering whether it was stupid to change the
example to something like:

diff --git a/examples/io_uring-cp.c b/examples/io_uring-cp.c
index cc7a227..2d6d190 100644
--- a/examples/io_uring-cp.c
+++ b/examples/io_uring-cp.c
@@ -170,11 +170,11 @@ static int copy_file(struct io_uring *ring, off_t insize)
     ret = io_uring_wait_cqe(ring, &cqe);
     got_comp = 1;
    } else {
-    ret = io_uring_peek_cqe(ring, &cqe);
-    if (ret == -EAGAIN) {
-     cqe = NULL;
-     ret = 0;
-    }
+    do {
+     ret = io_uring_peek_cqe(ring, &cqe)
+     if (ret != -EAGAIN)
+      break;
+    } while (1);
    }
    if (ret < 0) {
     fprintf(stderr, "io_uring_peek_cqe: %s\n",


Best,
-- 
William