On 23/09/23 10:50AM, Ming Lei wrote:
>Retain top 8bits of uring_cmd flags for kernel internal use, so that we
>can move IORING_URING_CMD_POLLED out of uapi header.
>

Looks good.

Reviewed-by: Anuj Gupta <anuj20.g@samsung.com>

>Signed-off-by: Ming Lei <ming.lei@redhat.com>
>---
> include/linux/io_uring.h      | 3 +++
> include/uapi/linux/io_uring.h | 5 ++---
> io_uring/io_uring.c           | 3 +++
> io_uring/uring_cmd.c          | 2 +-
> 4 files changed, 9 insertions(+), 4 deletions(-)
>
>diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h
>index 106cdc55ff3b..ae08d6f66e62 100644
>--- a/include/linux/io_uring.h
>+++ b/include/linux/io_uring.h
>@@ -22,6 +22,9 @@ enum io_uring_cmd_flags {
> 	IO_URING_F_IOPOLL		= (1 << 10),
> };
>
>+/* only top 8 bits of sqe->uring_cmd_flags for kernel internal use */
>+#define IORING_URING_CMD_POLLED		(1U << 31)
>+
> struct io_uring_cmd {
> 	struct file	*file;
> 	const struct io_uring_sqe *sqe;
>diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
>index 8e61f8b7c2ce..de77ad08b123 100644
>--- a/include/uapi/linux/io_uring.h
>+++ b/include/uapi/linux/io_uring.h
>@@ -246,13 +246,12 @@ enum io_uring_op {
> };
>
> /*
>- * sqe->uring_cmd_flags
>+ * sqe->uring_cmd_flags		top 8bits aren't available for userspace
>  * IORING_URING_CMD_FIXED	use registered buffer; pass this flag
>  *				along with setting sqe->buf_index.
>- * IORING_URING_CMD_POLLED	driver use only
>  */
> #define IORING_URING_CMD_FIXED	(1U << 0)
>-#define IORING_URING_CMD_POLLED	(1U << 31)
>+#define IORING_URING_CMD_MASK	IORING_URING_CMD_FIXED
>
>
> /*
>diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
>index 783ed0fff71b..9aedb7202403 100644
>--- a/io_uring/io_uring.c
>+++ b/io_uring/io_uring.c
>@@ -4666,6 +4666,9 @@ static int __init io_uring_init(void)
>
> 	BUILD_BUG_ON(sizeof(atomic_t) != sizeof(u32));
>
>+	/* top 8bits are for internal use */
>+	BUILD_BUG_ON((IORING_URING_CMD_MASK & 0xff000000) != 0);
>+
> 	io_uring_optable_init();
>
> 	/*
>diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c
>index 537795fddc87..a0b0ec5473bf 100644
>--- a/io_uring/uring_cmd.c
>+++ b/io_uring/uring_cmd.c
>@@ -91,7 +91,7 @@ int io_uring_cmd_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
> 		return -EINVAL;
>
> 	ioucmd->flags = READ_ONCE(sqe->uring_cmd_flags);
>-	if (ioucmd->flags & ~IORING_URING_CMD_FIXED)
>+	if (ioucmd->flags & ~IORING_URING_CMD_MASK)
> 		return -EINVAL;
>
> 	if (ioucmd->flags & IORING_URING_CMD_FIXED) {
>-- 
>2.41.0
>