[RFC PATCH v3 1/4] liburing: add api to set napi busy poll settings

[Stefan Roesch <shr@devkernel.io>]

This adds three functions to manage the napi busy poll settings:
- io_uring_register_napi_busy_poll_timeout
- io_uring_unregister_napi_busy_poll_timeout
- io_uring_register_napi_prefer_busy_poll

Signed-off-by: Stefan Roesch <shr@devkernel.io>
---
 src/include/liburing.h          |  6 ++++++
 src/include/liburing/io_uring.h |  4 ++++
 src/liburing.map                |  7 +++++++
 src/register.c                  | 23 +++++++++++++++++++++++
 4 files changed, 40 insertions(+)

diff --git a/src/include/liburing.h b/src/include/liburing.h
index 12a703f..47bbced 100644
--- a/src/include/liburing.h
+++ b/src/include/liburing.h
@@ -235,6 +235,12 @@ int io_uring_register_sync_cancel(struct io_uring *ring,
 int io_uring_register_file_alloc_range(struct io_uring *ring,
 					unsigned off, unsigned len);
 
+int io_uring_register_napi_prefer_busy_poll(struct io_uring *ring,
+					    bool prefer_busy_poll);
+int io_uring_register_napi_busy_poll_timeout(struct io_uring *ring,
+					     unsigned int to);
+int io_uring_unregister_napi_busy_poll_timeout(struct io_uring *ring);
+
 int io_uring_get_events(struct io_uring *ring);
 int io_uring_submit_and_get_events(struct io_uring *ring);
 
diff --git a/src/include/liburing/io_uring.h b/src/include/liburing/io_uring.h
index a3e0920..2e53f52 100644
--- a/src/include/liburing/io_uring.h
+++ b/src/include/liburing/io_uring.h
@@ -499,6 +499,10 @@ enum {
 	/* register a range of fixed file slots for automatic slot allocation */
 	IORING_REGISTER_FILE_ALLOC_RANGE	= 25,
 
+	/* set/clear busy poll settings */
+	IORING_REGISTER_NAPI_PREFER_BUSY_POLL	= 26,
+	IORING_REGISTER_NAPI_BUSY_POLL_TIMEOUT	= 27,
+
 	/* this goes last */
 	IORING_REGISTER_LAST
 };
diff --git a/src/liburing.map b/src/liburing.map
index 06c64f8..2e41a40 100644
--- a/src/liburing.map
+++ b/src/liburing.map
@@ -67,3 +67,10 @@ LIBURING_2.3 {
 		io_uring_get_events;
 		io_uring_submit_and_get_events;
 } LIBURING_2.2;
+
+LIBURING_2.4 {
+	global:
+		io_uring_napi_register_prefer_busy_poll;
+		io_uring_napi_register_busy_poll_timeout;
+		io_uring_napi_unregister_busy_poll_timeout;
+} LIBURING_2.3;
diff --git a/src/register.c b/src/register.c
index e849825..50250b8 100644
--- a/src/register.c
+++ b/src/register.c
@@ -367,3 +367,26 @@ int io_uring_register_file_alloc_range(struct io_uring *ring,
 				       IORING_REGISTER_FILE_ALLOC_RANGE, &range,
 				       0);
 }
+
+int io_uring_register_napi_prefer_busy_poll(struct io_uring *ring,
+					    bool prefer_busy_poll)
+{
+	return __sys_io_uring_register(ring->ring_fd,
+				IORING_REGISTER_NAPI_PREFER_BUSY_POLL,
+				NULL, prefer_busy_poll);
+}
+
+int io_uring_register_napi_busy_poll_timeout(struct io_uring *ring,
+					     unsigned int to)
+{
+	return __sys_io_uring_register(ring->ring_fd,
+				IORING_REGISTER_NAPI_BUSY_POLL_TIMEOUT,
+				NULL, to);
+}
+
+int io_uring_unregister_napi_busy_poll_timeout(struct io_uring *ring)
+{
+	return __sys_io_uring_register(ring->ring_fd,
+				IORING_REGISTER_NAPI_BUSY_POLL_TIMEOUT,
+				NULL, 0);
+}
-- 
2.30.2