From fc68fcda049108478ee4704d8a3ad3e05cc72fd0 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 11 Sep 2023 13:35:42 -0600 Subject: io_uring/rw: add support for IORING_OP_READ_MULTISHOT This behaves like IORING_OP_READ, except: 1) It only supports pollable files (eg pipes, sockets, etc). Note that for sockets, you probably want to use recv/recvmsg with multishot instead. 2) It supports multishot mode, meaning it will repeatedly trigger a read and fill a buffer when data is available. This allows similar use to recv/recvmsg but on non-sockets, where a single request will repeatedly post a CQE whenever data is read from it. 3) Because of #2, it must be used with provided buffers. This is uniformly true across any request type that supports multishot and transfers data, with the reason being that it's obviously not possible to pass in a single buffer for the data, as multiple reads may very well trigger before an application has a chance to process previous CQEs and the data passed from them. Reviewed-by: Gabriel Krisman Bertazi Signed-off-by: Jens Axboe --- include/uapi/linux/io_uring.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 8e61f8b7c2ce..d127948b0d8a 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -240,6 +240,7 @@ enum io_uring_op { IORING_OP_URING_CMD, IORING_OP_SEND_ZC, IORING_OP_SENDMSG_ZC, + IORING_OP_READ_MULTISHOT, /* this goes last, obviously */ IORING_OP_LAST, -- cgit v1.2.3 From f31ecf671ddc498f20219453395794ff2383e06b Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 10 Jul 2023 16:14:37 -0600 Subject: io_uring: add IORING_OP_WAITID support This adds support for an async version of waitid(2), in a fully async version. If an event isn't immediately available, wait for a callback to trigger a retry. The format of the sqe is as follows: sqe->len The 'which', the idtype being queried/waited for. sqe->fd The 'pid' (or id) being waited for. sqe->file_index The 'options' being set. sqe->addr2 A pointer to siginfo_t, if any, being filled in. buf_index, add3, and waitid_flags are reserved/unused for now. waitid_flags will be used for options for this request type. One interesting use case may be to add multi-shot support, so that the request stays armed and posts a notification every time a monitored process state change occurs. Note that this does not support rusage, on Arnd's recommendation. See the waitid(2) man page for details on the arguments. Signed-off-by: Jens Axboe --- include/uapi/linux/io_uring.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index d127948b0d8a..683ac2b74721 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -65,6 +65,7 @@ struct io_uring_sqe { __u32 xattr_flags; __u32 msg_ring_flags; __u32 uring_cmd_flags; + __u32 waitid_flags; }; __u64 user_data; /* data to be passed back at completion time */ /* pack this to avoid bogus arm OABI complaints */ @@ -241,6 +242,7 @@ enum io_uring_op { IORING_OP_SEND_ZC, IORING_OP_SENDMSG_ZC, IORING_OP_READ_MULTISHOT, + IORING_OP_WAITID, /* this goes last, obviously */ IORING_OP_LAST, -- cgit v1.2.3 From 528ce6781726e022bc5dc84034360e6e8f1b89bd Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Thu, 28 Sep 2023 20:43:24 +0800 Subject: io_uring: retain top 8bits of uring_cmd flags for kernel internal use Retain top 8bits of uring_cmd flags for kernel internal use, so that we can move IORING_URING_CMD_POLLED out of uapi header. Reviewed-by: Gabriel Krisman Bertazi Reviewed-by: Anuj Gupta Signed-off-by: Ming Lei Signed-off-by: Jens Axboe --- include/uapi/linux/io_uring.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'include/uapi/linux') diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 683ac2b74721..425f64eee44e 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -249,13 +249,12 @@ 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 /* -- cgit v1.2.3