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From: Kanchan Joshi <[email protected]>
To: [email protected], [email protected], [email protected],
	[email protected]
Cc: [email protected], [email protected],
	[email protected], [email protected],
	[email protected], [email protected],
	Kanchan Joshi <[email protected]>
Subject: [RFC PATCH v3 1/3] io_uring: add helper for uring_cmd completion in submitter-task
Date: Tue, 16 Mar 2021 19:31:24 +0530	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

Completion of a uring_cmd ioctl may involve referencing certain
ioctl-specific fields, requiring original subitter context.
Introduce 'uring_cmd_complete_in_task' that driver can use for this
purpose. The API facilitates task-work infra, while driver gets to
implement cmd-specific handling in a callback.

Signed-off-by: Kanchan Joshi <[email protected]>
---
 fs/io_uring.c            | 36 ++++++++++++++++++++++++++++++++----
 include/linux/io_uring.h |  8 ++++++++
 2 files changed, 40 insertions(+), 4 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 583f8fd735d8..ca459ea9cb83 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -772,9 +772,12 @@ struct io_kiocb {
 		/* use only after cleaning per-op data, see io_clean_op() */
 		struct io_completion	compl;
 	};
-
-	/* opcode allocated if it needs to store data for async defer */
-	void				*async_data;
+	union {
+		/* opcode allocated if it needs to store data for async defer */
+		void				*async_data;
+		/* used for uring-cmd, when driver needs to update in task */
+		void (*driver_cb)(struct io_uring_cmd *cmd);
+	};
 	u8				opcode;
 	/* polled IO has completed */
 	u8				iopoll_completed;
@@ -1716,7 +1719,7 @@ static void io_dismantle_req(struct io_kiocb *req)
 {
 	io_clean_op(req);
 
-	if (req->async_data)
+	if (io_op_defs[req->opcode].async_size && req->async_data)
 		kfree(req->async_data);
 	if (req->file)
 		io_put_file(req, req->file, (req->flags & REQ_F_FIXED_FILE));
@@ -2032,6 +2035,31 @@ static void io_req_task_submit(struct callback_head *cb)
 	__io_req_task_submit(req);
 }
 
+static void uring_cmd_work(struct callback_head *cb)
+{
+	struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
+	struct io_uring_cmd *cmd = &req->uring_cmd;
+
+	req->driver_cb(cmd);
+}
+int uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd,
+			void (*driver_cb)(struct io_uring_cmd *))
+{
+	int ret;
+	struct io_kiocb *req = container_of(ioucmd, struct io_kiocb, uring_cmd);
+
+	req->driver_cb = driver_cb;
+	req->task_work.func = uring_cmd_work;
+	ret = io_req_task_work_add(req);
+	if (unlikely(ret)) {
+		req->result = -ECANCELED;
+		percpu_ref_get(&req->ctx->refs);
+		io_req_task_work_add_fallback(req, io_req_task_cancel);
+	}
+	return ret;
+}
+EXPORT_SYMBOL(uring_cmd_complete_in_task);
+
 static void io_req_task_queue(struct io_kiocb *req)
 {
 	int ret;
diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h
index e0a31354eff1..559f41d0f19a 100644
--- a/include/linux/io_uring.h
+++ b/include/linux/io_uring.h
@@ -41,6 +41,8 @@ struct io_uring_cmd {
 
 #if defined(CONFIG_IO_URING)
 void io_uring_cmd_done(struct io_uring_cmd *cmd, ssize_t ret);
+int uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd,
+			void (*driver_cb)(struct io_uring_cmd *));
 struct sock *io_uring_get_socket(struct file *file);
 void __io_uring_task_cancel(void);
 void __io_uring_files_cancel(struct files_struct *files);
@@ -65,6 +67,12 @@ static inline void io_uring_free(struct task_struct *tsk)
 static inline void io_uring_cmd_done(struct io_uring_cmd *cmd, ssize_t ret)
 {
 }
+
+int uring_cmd_complete_in_task(struct io_uring_cmd *ioucmd,
+			void (*driver_cb)(struct io_uring_cmd *))
+{
+	return -1;
+}
 static inline struct sock *io_uring_get_socket(struct file *file)
 {
 	return NULL;
-- 
2.25.1


  parent reply	other threads:[~2021-03-16 14:03 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <CGME20210316140229epcas5p23d68a4c9694bbf7759b5901115a4309b@epcas5p2.samsung.com>
2021-03-16 14:01 ` [RFC PATCH v3 0/3] Async nvme passthrough over io_uring Kanchan Joshi
     [not found]   ` <CGME20210316140233epcas5p372405e7cb302c61dba5e1094fa796513@epcas5p3.samsung.com>
2021-03-16 14:01     ` Kanchan Joshi [this message]
2021-03-16 15:43       ` [RFC PATCH v3 1/3] io_uring: add helper for uring_cmd completion in submitter-task Stefan Metzmacher
2021-03-18  1:57       ` Jens Axboe
2021-03-18  5:25         ` Kanchan Joshi
2021-03-18  5:48           ` Christoph Hellwig
2021-03-18  6:14             ` Kanchan Joshi
     [not found]   ` <CGME20210316140236epcas5p4de087ee51a862402146fbbc621d4d4c6@epcas5p4.samsung.com>
2021-03-16 14:01     ` [RFC PATCH v3 2/3] nvme: keep nvme_command instead of pointer to it Kanchan Joshi
2021-03-16 17:16       ` Keith Busch
2021-03-17  9:38         ` Kanchan Joshi
2021-03-17 14:17           ` Keith Busch
     [not found]   ` <CGME20210316140240epcas5p3e71bfe2afecd728c5af60056f21cc9b7@epcas5p3.samsung.com>
2021-03-16 14:01     ` [RFC PATCH v3 3/3] nvme: wire up support for async passthrough Kanchan Joshi
2021-03-17  8:52       ` Christoph Hellwig
2021-03-17 16:49         ` Jens Axboe
2021-03-17 16:59           ` Christoph Hellwig
2021-03-17 17:21             ` Jens Axboe
2021-03-17 18:59               ` Jens Axboe
2021-03-18  5:54         ` Kanchan Joshi
2021-03-17 16:45       ` Keith Busch
2021-03-17 17:02         ` Christoph Hellwig
2021-03-16 15:51   ` [RFC PATCH v3 0/3] Async nvme passthrough over io_uring Jens Axboe
2021-03-17  9:31     ` Kanchan Joshi
2021-03-18  1:58       ` Jens Axboe
2021-03-18  7:47         ` Kanchan Joshi

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