io_uring: add support for IORING_OP_ACCEPT

This allows an application to call accept4() in an async fashion. Like
other opcodes, we first try a non-blocking accept, then punt to async
context if we have to.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 6e1523567920c0bfe0914e3c28076c1569276aad..b668149c20b9a5dcd30a0ee4024e726d0c17d146 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1686,6 +1686,40 @@ static int io_recvmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 #endif
 }
 
+static int io_accept(struct io_kiocb *req, const struct io_uring_sqe *sqe,
+                    struct io_kiocb **nxt, bool force_nonblock)
+{
+#if defined(CONFIG_NET)
+       struct sockaddr __user *addr;
+       int __user *addr_len;
+       unsigned file_flags;
+       int flags, ret;
+
+       if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL)))
+               return -EINVAL;
+       if (sqe->ioprio || sqe->off || sqe->len || sqe->buf_index)
+               return -EINVAL;
+
+       addr = (struct sockaddr __user *) (unsigned long) READ_ONCE(sqe->addr);
+       addr_len = (int __user *) (unsigned long) READ_ONCE(sqe->addr2);
+       flags = READ_ONCE(sqe->accept_flags);
+       file_flags = force_nonblock ? O_NONBLOCK : 0;
+
+       ret = __sys_accept4_file(req->file, file_flags, addr, addr_len, flags);
+       if (ret == -EAGAIN && force_nonblock) {
+               req->work.flags |= IO_WQ_WORK_NEEDS_FILES;
+               return -EAGAIN;
+       }
+       if (ret < 0 && (req->flags & REQ_F_LINK))
+               req->flags |= REQ_F_FAIL_LINK;
+       io_cqring_add_event(req->ctx, sqe->user_data, ret);
+       io_put_req(req, nxt);
+       return 0;
+#else
+       return -EOPNOTSUPP;
+#endif
+}
+
 static void io_poll_remove_one(struct io_kiocb *req)
 {
        struct io_poll_iocb *poll = &req->poll;
@@ -2173,6 +2207,9 @@ static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
        case IORING_OP_TIMEOUT_REMOVE:
                ret = io_timeout_remove(req, s->sqe);
                break;
+       case IORING_OP_ACCEPT:
+               ret = io_accept(req, s->sqe, nxt, force_nonblock);
+               break;
        default:
                ret = -EINVAL;
                break;

diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h
index 6dc5ced1c37ad9d7dcaf4d4b6a1f03f78fe44ce8..f82d90e617a6fbc03ba988cec9134bc289bd75f4 100644 (file)
--- a/include/uapi/linux/io_uring.h
+++ b/include/uapi/linux/io_uring.h
@@ -19,7 +19,10 @@ struct io_uring_sqe {
        __u8    flags;          /* IOSQE_ flags */
        __u16   ioprio;         /* ioprio for the request */
        __s32   fd;             /* file descriptor to do IO on */
-       __u64   off;            /* offset into file */
+       union {
+               __u64   off;    /* offset into file */
+               __u64   addr2;
+       };
        __u64   addr;           /* pointer to buffer or iovecs */
        __u32   len;            /* buffer size or number of iovecs */
        union {
@@ -29,6 +32,7 @@ struct io_uring_sqe {
                __u32           sync_range_flags;
                __u32           msg_flags;
                __u32           timeout_flags;
+               __u32           accept_flags;
        };
        __u64   user_data;      /* data to be passed back at completion time */
        union {
@@ -65,6 +69,7 @@ struct io_uring_sqe {
 #define IORING_OP_RECVMSG      10
 #define IORING_OP_TIMEOUT      11
 #define IORING_OP_TIMEOUT_REMOVE       12
+#define IORING_OP_ACCEPT       13
 
 /*
  * sqe->fsync_flags