man/io_uring_register_ring_fd.3: try to improve NOTES section
Threaded applications can use this optimization, but they cannot use it
if they share any given ring between multiple threads.
Link:
@@ -35,9 +35,10 @@ for restrictions when a ring is shared.
.SH NOTES
When the ring descriptor is registered, it is stored internally in the
.I struct io_uring
-structure. If an application shares this structure between threads, then this
-optimization cannot be used as the threads may get different values for the
-registered descriptor.
+structure. For applications that share a ring between threads, for example
+having one thread do submits and another reap events, then this optimization
+cannot be used as each thread may have a different index for the registered
+ring fd.
.SH RETURN VALUE
Returns 1 on success, indicating that one file descriptor was registered,
or
