From: Kanchan Joshi <joshi.k@samsung.com>
Date: Tue, 23 Aug 2022 16:14:41 +0000 (+0530)
Subject: io_uring: add iopoll infrastructure for io_uring_cmd
X-Git-Tag: v6.1-rc5~284^2~46
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=5756a3a7e713bcab705a5f0c810a2b1f7f4ecfaa;p=platform%2Fkernel%2Flinux-starfive.git

io_uring: add iopoll infrastructure for io_uring_cmd

Put this up in the same way as iopoll is done for regular read/write IO.
Make place for storing a cookie into struct io_uring_cmd on submission.
Perform the completion using the ->uring_cmd_iopoll handler.

Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
Link: https://lore.kernel.org/r/20220823161443.49436-3-joshi.k@samsung.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h
index 4a2f6cc..58676c0 100644
--- a/include/linux/io_uring.h
+++ b/include/linux/io_uring.h
@@ -20,8 +20,12 @@ enum io_uring_cmd_flags {
 struct io_uring_cmd {
 	struct file	*file;
 	const void	*cmd;
-	/* callback to defer completions to task context */
-	void (*task_work_cb)(struct io_uring_cmd *cmd);
+	union {
+		/* callback to defer completions to task context */
+		void (*task_work_cb)(struct io_uring_cmd *cmd);
+		/* used for polled completion */
+		void *cookie;
+	};
 	u32		cmd_op;
 	u32		pad;
 	u8		pdu[32]; /* available inline for free use */
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index d99b31a..31ac87e 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -1433,6 +1433,12 @@ static int io_iopoll_check(struct io_ring_ctx *ctx, long min)
 			    wq_list_empty(&ctx->iopoll_list))
 				break;
 		}
+
+		if (task_work_pending(current)) {
+			mutex_unlock(&ctx->uring_lock);
+			io_run_task_work();
+			mutex_lock(&ctx->uring_lock);
+		}
 		ret = io_do_iopoll(ctx, !min);
 		if (ret < 0)
 			break;
diff --git a/io_uring/opdef.c b/io_uring/opdef.c
index c4dddd0..008320c 100644
--- a/io_uring/opdef.c
+++ b/io_uring/opdef.c
@@ -465,6 +465,7 @@ const struct io_op_def io_op_defs[] = {
 		.needs_file		= 1,
 		.plug			= 1,
 		.name			= "URING_CMD",
+		.iopoll			= 1,
 		.async_size		= uring_cmd_pdu_size(1),
 		.prep			= io_uring_cmd_prep,
 		.issue			= io_uring_cmd,
diff --git a/io_uring/rw.c b/io_uring/rw.c
index 76ebcfe..b6f9c75 100644
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -1011,7 +1011,13 @@ int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin)
 		if (READ_ONCE(req->iopoll_completed))
 			break;
 
-		ret = rw->kiocb.ki_filp->f_op->iopoll(&rw->kiocb, &iob, poll_flags);
+		if (req->opcode == IORING_OP_URING_CMD) {
+			struct io_uring_cmd *ioucmd = (struct io_uring_cmd *)rw;
+
+			ret = req->file->f_op->uring_cmd_iopoll(ioucmd);
+		} else
+			ret = rw->kiocb.ki_filp->f_op->iopoll(&rw->kiocb, &iob,
+							poll_flags);
 		if (unlikely(ret < 0))
 			return ret;
 		else if (ret)
diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c
index e78b6f9..f3ed61e 100644
--- a/io_uring/uring_cmd.c
+++ b/io_uring/uring_cmd.c
@@ -50,7 +50,11 @@ void io_uring_cmd_done(struct io_uring_cmd *ioucmd, ssize_t ret, ssize_t res2)
 	io_req_set_res(req, ret, 0);
 	if (req->ctx->flags & IORING_SETUP_CQE32)
 		io_req_set_cqe32_extra(req, res2, 0);
-	__io_req_complete(req, 0);
+	if (req->ctx->flags & IORING_SETUP_IOPOLL)
+		/* order with io_iopoll_req_issued() checking ->iopoll_complete */
+		smp_store_release(&req->iopoll_completed, 1);
+	else
+		__io_req_complete(req, 0);
 }
 EXPORT_SYMBOL_GPL(io_uring_cmd_done);
 
@@ -97,8 +101,11 @@ int io_uring_cmd(struct io_kiocb *req, unsigned int issue_flags)
 		issue_flags |= IO_URING_F_SQE128;
 	if (ctx->flags & IORING_SETUP_CQE32)
 		issue_flags |= IO_URING_F_CQE32;
-	if (ctx->flags & IORING_SETUP_IOPOLL)
+	if (ctx->flags & IORING_SETUP_IOPOLL) {
 		issue_flags |= IO_URING_F_IOPOLL;
+		req->iopoll_completed = 0;
+		WRITE_ONCE(ioucmd->cookie, NULL);
+	}
 
 	if (req_has_async_data(req))
 		ioucmd->cmd = req->async_data;