1 files changed, 117 insertions, 47 deletions

diff --git a/io_uring/msg_ring.c b/io_uring/msg_ring.c
index afb543aab9f6..2d3cd945a531 100644
--- a/io_uring/msg_ring.c
+++ b/io_uring/msg_ring.c
@@ -15,6 +15,8 @@
 
 struct io_msg {
 	struct file			*file;
+	struct file			*src_file;
+	struct callback_head		tw;
 	u64 user_data;
 	u32 len;
 	u32 cmd;
@@ -23,6 +25,34 @@ struct io_msg {
 	u32 flags;
 };
 
+void io_msg_ring_cleanup(struct io_kiocb *req)
+{
+	struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
+
+	if (WARN_ON_ONCE(!msg->src_file))
+		return;
+
+	fput(msg->src_file);
+	msg->src_file = NULL;
+}
+
+static void io_msg_tw_complete(struct callback_head *head)
+{
+	struct io_msg *msg = container_of(head, struct io_msg, tw);
+	struct io_kiocb *req = cmd_to_io_kiocb(msg);
+	struct io_ring_ctx *target_ctx = req->file->private_data;
+	int ret = 0;
+
+	if (current->flags & PF_EXITING)
+		ret = -EOWNERDEAD;
+	else if (!io_post_aux_cqe(target_ctx, msg->user_data, msg->len, 0))
+		ret = -EOVERFLOW;
+
+	if (ret < 0)
+		req_set_fail(req);
+	io_req_queue_tw_complete(req, ret);
+}
+
 static int io_msg_ring_data(struct io_kiocb *req)
 {
 	struct io_ring_ctx *target_ctx = req->file->private_data;
@@ -31,23 +61,29 @@ static int io_msg_ring_data(struct io_kiocb *req)
 	if (msg->src_fd || msg->dst_fd || msg->flags)
 		return -EINVAL;
 
+	if (target_ctx->task_complete && current != target_ctx->submitter_task) {
+		init_task_work(&msg->tw, io_msg_tw_complete);
+		if (task_work_add(target_ctx->submitter_task, &msg->tw,
+				  TWA_SIGNAL_NO_IPI))
+			return -EOWNERDEAD;
+
+		atomic_or(IORING_SQ_TASKRUN, &target_ctx->rings->sq_flags);
+		return IOU_ISSUE_SKIP_COMPLETE;
+	}
+
 	if (io_post_aux_cqe(target_ctx, msg->user_data, msg->len, 0))
 		return 0;
 
 	return -EOVERFLOW;
 }
 
-static void io_double_unlock_ctx(struct io_ring_ctx *ctx,
-				 struct io_ring_ctx *octx,
+static void io_double_unlock_ctx(struct io_ring_ctx *octx,
 				 unsigned int issue_flags)
 {
-	if (issue_flags & IO_URING_F_UNLOCKED)
-		mutex_unlock(&ctx->uring_lock);
 	mutex_unlock(&octx->uring_lock);
 }
 
-static int io_double_lock_ctx(struct io_ring_ctx *ctx,
-			      struct io_ring_ctx *octx,
+static int io_double_lock_ctx(struct io_ring_ctx *octx,
 			      unsigned int issue_flags)
 {
 	/*
@@ -60,56 +96,49 @@ static int io_double_lock_ctx(struct io_ring_ctx *ctx,
 			return -EAGAIN;
 		return 0;
 	}
-
-	/* Always grab smallest value ctx first. We know ctx != octx. */
-	if (ctx < octx) {
-		mutex_lock(&ctx->uring_lock);
-		mutex_lock(&octx->uring_lock);
-	} else {
-		mutex_lock(&octx->uring_lock);
-		mutex_lock(&ctx->uring_lock);
-	}
-
+	mutex_lock(&octx->uring_lock);
 	return 0;
 }
 
-static int io_msg_send_fd(struct io_kiocb *req, unsigned int issue_flags)
+static struct file *io_msg_grab_file(struct io_kiocb *req, unsigned int issue_flags)
 {
-	struct io_ring_ctx *target_ctx = req->file->private_data;
 	struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
 	struct io_ring_ctx *ctx = req->ctx;
+	struct file *file = NULL;
 	unsigned long file_ptr;
-	struct file *src_file;
-	int ret;
-
-	if (target_ctx == ctx)
-		return -EINVAL;
-
-	ret = io_double_lock_ctx(ctx, target_ctx, issue_flags);
-	if (unlikely(ret))
-		return ret;
-
-	ret = -EBADF;
-	if (unlikely(msg->src_fd >= ctx->nr_user_files))
-		goto out_unlock;
+	int idx = msg->src_fd;
+
+	io_ring_submit_lock(ctx, issue_flags);
+	if (likely(idx < ctx->nr_user_files)) {
+		idx = array_index_nospec(idx, ctx->nr_user_files);
+		file_ptr = io_fixed_file_slot(&ctx->file_table, idx)->file_ptr;
+		file = (struct file *) (file_ptr & FFS_MASK);
+		if (file)
+			get_file(file);
+	}
+	io_ring_submit_unlock(ctx, issue_flags);
+	return file;
+}
 
-	msg->src_fd = array_index_nospec(msg->src_fd, ctx->nr_user_files);
-	file_ptr = io_fixed_file_slot(&ctx->file_table, msg->src_fd)->file_ptr;
-	if (!file_ptr)
-		goto out_unlock;
+static int io_msg_install_complete(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_ring_ctx *target_ctx = req->file->private_data;
+	struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
+	struct file *src_file = msg->src_file;
+	int ret;
 
-	src_file = (struct file *) (file_ptr & FFS_MASK);
-	get_file(src_file);
+	if (unlikely(io_double_lock_ctx(target_ctx, issue_flags)))
+		return -EAGAIN;
 
 	ret = __io_fixed_fd_install(target_ctx, src_file, msg->dst_fd);
-	if (ret < 0) {
-		fput(src_file);
+	if (ret < 0)
 		goto out_unlock;
-	}
+
+	msg->src_file = NULL;
+	req->flags &= ~REQ_F_NEED_CLEANUP;
 
 	if (msg->flags & IORING_MSG_RING_CQE_SKIP)
 		goto out_unlock;
-
 	/*
 	 * If this fails, the target still received the file descriptor but
 	 * wasn't notified of the fact. This means that if this request
@@ -119,10 +148,51 @@ static int io_msg_send_fd(struct io_kiocb *req, unsigned int issue_flags)
 	if (!io_post_aux_cqe(target_ctx, msg->user_data, msg->len, 0))
 		ret = -EOVERFLOW;
 out_unlock:
-	io_double_unlock_ctx(ctx, target_ctx, issue_flags);
+	io_double_unlock_ctx(target_ctx, issue_flags);
 	return ret;
 }
 
+static void io_msg_tw_fd_complete(struct callback_head *head)
+{
+	struct io_msg *msg = container_of(head, struct io_msg, tw);
+	struct io_kiocb *req = cmd_to_io_kiocb(msg);
+	int ret = -EOWNERDEAD;
+
+	if (!(current->flags & PF_EXITING))
+		ret = io_msg_install_complete(req, IO_URING_F_UNLOCKED);
+	if (ret < 0)
+		req_set_fail(req);
+	io_req_queue_tw_complete(req, ret);
+}
+
+static int io_msg_send_fd(struct io_kiocb *req, unsigned int issue_flags)
+{
+	struct io_ring_ctx *target_ctx = req->file->private_data;
+	struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
+	struct io_ring_ctx *ctx = req->ctx;
+	struct file *src_file = msg->src_file;
+
+	if (target_ctx == ctx)
+		return -EINVAL;
+	if (!src_file) {
+		src_file = io_msg_grab_file(req, issue_flags);
+		if (!src_file)
+			return -EBADF;
+		msg->src_file = src_file;
+		req->flags |= REQ_F_NEED_CLEANUP;
+	}
+
+	if (target_ctx->task_complete && current != target_ctx->submitter_task) {
+		init_task_work(&msg->tw, io_msg_tw_fd_complete);
+		if (task_work_add(target_ctx->submitter_task, &msg->tw,
+				  TWA_SIGNAL))
+			return -EOWNERDEAD;
+
+		return IOU_ISSUE_SKIP_COMPLETE;
+	}
+	return io_msg_install_complete(req, issue_flags);
+}
+
 int io_msg_ring_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
 	struct io_msg *msg = io_kiocb_to_cmd(req, struct io_msg);
@@ -130,6 +200,7 @@ int io_msg_ring_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	if (unlikely(sqe->buf_index || sqe->personality))
 		return -EINVAL;
 
+	msg->src_file = NULL;
 	msg->user_data = READ_ONCE(sqe->off);
 	msg->len = READ_ONCE(sqe->len);
 	msg->cmd = READ_ONCE(sqe->addr);
@@ -164,12 +235,11 @@ int io_msg_ring(struct io_kiocb *req, unsigned int issue_flags)
 	}
 
 done:
-	if (ret < 0)
+	if (ret < 0) {
+		if (ret == -EAGAIN || ret == IOU_ISSUE_SKIP_COMPLETE)
+			return ret;
 		req_set_fail(req);
+	}
 	io_req_set_res(req, ret, 0);
-	/* put file to avoid an attempt to IOPOLL the req */
-	if (!(req->flags & REQ_F_FIXED_FILE))
-		io_put_file(req->file);
-	req->file = NULL;
 	return IOU_OK;
 }