[PATCH v9 5/5] io_uring: add prefer busy poll to register and unregister napi api

Stefan Roesch
2023-02-15T17:45:30Z

This adds the napi prefer busy poll setting to the register and
unregister napi api. When napi is unregistered and arg is specified,
both napi settings: busy poll timeout and the prefer busy poll setting
are copied into the user structure.

Signed-off-by: Stefan Roesch <shr@devkernel.io>
Acked-by: Jakub Kicinski <kuba@kernel.org>
---
include/uapi/linux/io_uring.h | 3 ++-
io_uring/napi.c | 6 +++++-
2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index fe25ae92744d..e14f31a4b10c 100644
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -647,7 +647,8 @@ struct io_uring_buf_reg {
/* argument for IORING_(UN)REGISTER_NAPI */
struct io_uring_napi {
__u32 busy_poll_to;
- __u32 pad;
+ __u8 prefer_busy_poll;
+ __u8 pad[3];
__u64 resv;
};

diff --git a/io_uring/napi.c b/io_uring/napi.c
index 56a4754efcfb..ca12ff5f5611 100644
--- a/io_uring/napi.c
+++ b/io_uring/napi.c
@@ -207,15 +207,17 @@ int io_register_napi(struct io_ring_ctx *ctx, void __user *arg)
{
const struct io_uring_napi curr = {
.busy_poll_to = ctx->napi_busy_poll_to,
+ .prefer_busy_poll = ctx->napi_prefer_busy_poll
};
struct io_uring_napi napi;

if (copy_from_user(&napi, arg, sizeof(napi)))
return -EFAULT;
- if (napi.pad || napi.resv)
+ if (napi.pad[0] || napi.pad[1] || napi.pad[2] || napi.resv)
return -EINVAL;

WRITE_ONCE(ctx->napi_busy_poll_to, napi.busy_poll_to);
+ WRITE_ONCE(ctx->napi_prefer_busy_poll, !!napi.prefer_busy_poll);

if (copy_to_user(arg, &curr, sizeof(curr)))
return -EFAULT;
@@ -235,6 +237,7 @@ int io_unregister_napi(struct io_ring_ctx *ctx, void __user *arg)
{
const struct io_uring_napi curr = {
.busy_poll_to = ctx->napi_busy_poll_to,
+ .prefer_busy_poll = ctx->napi_prefer_busy_poll
};

if (arg) {
@@ -243,6 +246,7 @@ int io_unregister_napi(struct io_ring_ctx *ctx, void __user *arg)
}

WRITE_ONCE(ctx->napi_busy_poll_to, 0);
+ WRITE_ONCE(ctx->napi_prefer_busy_poll, false);
return 0;
}

--
2.30.2