commit 36f4fa6886a81266d7c82b1c90a65205e73a7c85
author Jens Axboe <axboe@kernel.dk> Sat Sep 05 11:14:22 2020 -0600
committer Jens Axboe <axboe@kernel.dk> Mon Nov 23 09:15:15 2020 -0700
tree 4701e9c5a955a6f754aaf058a5a721e9ddb1239e
parent b713c195d59332277a31a59c91f755e53b5b302b

io_uring: add support for shutdown(2)

This adds support for the shutdown(2) system call, which is useful for
dealing with sockets.

shutdown(2) may block, so we have to punt it to async context.

Suggested-by: Norman Maurer <norman.maurer@googlemail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 3cc1e59..d171987 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -541,6 +541,11 @@ struct io_statx {
 	struct statx __user		*buffer;
 };
 
+struct io_shutdown {
+	struct file			*file;
+	int				how;
+};
+
 struct io_completion {
 	struct file			*file;
 	struct list_head		list;
@@ -667,6 +672,7 @@ struct io_kiocb {
 		struct io_splice	splice;
 		struct io_provide_buf	pbuf;
 		struct io_statx		statx;
+		struct io_shutdown	shutdown;
 		/* use only after cleaning per-op data, see io_clean_op() */
 		struct io_completion	compl;
 	};
@@ -934,6 +940,9 @@ static const struct io_op_def io_op_defs[] = {
 		.hash_reg_file		= 1,
 		.unbound_nonreg_file	= 1,
 	},
+	[IORING_OP_SHUTDOWN] = {
+		.needs_file		= 1,
+	},
 };
 
 enum io_mem_account {
@@ -3591,6 +3600,44 @@ static int io_write(struct io_kiocb *req, bool force_nonblock,
 	return ret;
 }
 
+static int io_shutdown_prep(struct io_kiocb *req,
+			    const struct io_uring_sqe *sqe)
+{
+#if defined(CONFIG_NET)
+	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
+		return -EINVAL;
+	if (sqe->ioprio || sqe->off || sqe->addr || sqe->rw_flags ||
+	    sqe->buf_index)
+		return -EINVAL;
+
+	req->shutdown.how = READ_ONCE(sqe->len);
+	return 0;
+#else
+	return -EOPNOTSUPP;
+#endif
+}
+
+static int io_shutdown(struct io_kiocb *req, bool force_nonblock)
+{
+#if defined(CONFIG_NET)
+	struct socket *sock;
+	int ret;
+
+	if (force_nonblock)
+		return -EAGAIN;
+
+	sock = sock_from_file(req->file, &ret);
+	if (unlikely(!sock))
+		return ret;
+
+	ret = __sys_shutdown_sock(sock, req->shutdown.how);
+	io_req_complete(req, ret);
+	return 0;
+#else
+	return -EOPNOTSUPP;
+#endif
+}
+
 static int __io_splice_prep(struct io_kiocb *req,
 			    const struct io_uring_sqe *sqe)
 {
@@ -5775,6 +5822,8 @@ static int io_req_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 		return io_remove_buffers_prep(req, sqe);
 	case IORING_OP_TEE:
 		return io_tee_prep(req, sqe);
+	case IORING_OP_SHUTDOWN:
+		return io_shutdown_prep(req, sqe);
 	}
 
 	printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n",
@@ -6018,6 +6067,9 @@ static int io_issue_sqe(struct io_kiocb *req, bool force_nonblock,
 	case IORING_OP_TEE:
 		ret = io_tee(req, force_nonblock);
 		break;
+	case IORING_OP_SHUTDOWN:
+		ret = io_shutdown(req, force_nonblock);
+		break;
 	default:
 		ret = -EINVAL;
 		break;