man/io_uring_submit.3: add blurb on passed in data being stable
Link:
@@ -10,7 +10,7 @@ io_uring_submit - submit requests to the submission queue
.nf
.BR "#include <liburing.h>"
.PP
-.BI "int io_uring_submit(struct io_uring *ring)"
+.BI "int io_uring_submit(struct io_uring *ring);"
.PP
.SH DESCRIPTION
.PP
@@ -18,12 +18,26 @@ The io_uring_submit() function submits the next events to the submission
queue belonging to the
.I ring.
-After the caller retrieves a submission queue entry (SQE) with io_uring_get_sqe(),
-prepares the SQE, it can be submitted with io_uring_submit().
+After the caller retrieves a submission queue entry (SQE) with
+.BR io_uring_get_sqe (3)
+and prepares the SQE, it can be submitted with io_uring_submit().
.SH RETURN VALUE
On success
.BR io_uring_submit (3)
-returns the number of submitted submission queue entries. On failure it returns -errno.
+returns the number of submitted submission queue entries. On failure it returns
+.B -errno.
+.SH NOTES
+For any request that passes in data in a struct, that data must remain
+valid until the request has been successfully submitted. It need not remain
+valid until completion. Once a request has been submitted, the in-kernel
+state is stable. Very early kernels (5.4 and earlier) required state to be
+stable until the completion occurred. Applications can test for this
+behavior by inspecting the
+.B IORING_FEAT_SUBMIT_STABLE
+flag passed back from
+.BR io_uring_queue_init_params (3).
+In general, the man pages for the individual prep helpers will have a note
+mentioning this fact as well, if required for the given command.
.SH SEE ALSO
.BR io_uring_get_sqe (3), io_uring_submit_and_wait (3), io_uring_submit_and_wait_timeout (3)
