[PATCH] io_uring/uring_cmd: skip io_uring_cmd_issue_blocking() task work

[PATCH] io_uring/uring_cmd: skip io_uring_cmd_issue_blocking() task work

[Caleb Sander Mateos]

io_uring_cmd_issue_blocking() is only called from blk_cmd_complete(),
which is already a task work callback. However, it queues another task
work item, to call io_queue_iowq(). Just call io_queue_iowq() directly
to skip the CPU cost and latency of the redundant task work proxying.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
---
 io_uring/io_uring.c  | 13 +------------
 io_uring/io_uring.h  |  2 +-
 io_uring/uring_cmd.c |  2 +-
 3 files changed, 3 insertions(+), 14 deletions(-)

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 1279e27c2c6d..4c83a94b4bdc 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -405,11 +405,11 @@ static void io_prep_async_link(struct io_kiocb *req)
 		io_for_each_link(cur, req)
 			io_prep_async_work(cur);
 	}
 }
 
-static void io_queue_iowq(struct io_kiocb *req)
+void io_queue_iowq(struct io_kiocb *req)
 {
 	struct io_uring_task *tctx = req->tctx;
 
 	BUG_ON(!tctx);
 
@@ -433,21 +433,10 @@ static void io_queue_iowq(struct io_kiocb *req)
 
 	trace_io_uring_queue_async_work(req, io_wq_is_hashed(&req->work));
 	io_wq_enqueue(tctx->io_wq, &req->work);
 }
 
-static void io_req_queue_iowq_tw(struct io_tw_req tw_req, io_tw_token_t tw)
-{
-	io_queue_iowq(tw_req.req);
-}
-
-void io_req_queue_iowq(struct io_kiocb *req)
-{
-	req->io_task_work.func = io_req_queue_iowq_tw;
-	io_req_task_work_add(req);
-}
-
 unsigned io_linked_nr(struct io_kiocb *req)
 {
 	struct io_kiocb *tmp;
 	unsigned nr = 0;
 
diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h
index cb736b815422..dfe26a9c21bf 100644
--- a/io_uring/io_uring.h
+++ b/io_uring/io_uring.h
@@ -193,11 +193,11 @@ void io_req_task_queue_fail(struct io_kiocb *req, int ret);
 void io_req_task_submit(struct io_tw_req tw_req, io_tw_token_t tw);
 __cold void io_uring_drop_tctx_refs(struct task_struct *task);
 
 int io_ring_add_registered_file(struct io_uring_task *tctx, struct file *file,
 				     int start, int end);
-void io_req_queue_iowq(struct io_kiocb *req);
+void io_queue_iowq(struct io_kiocb *req);
 
 int io_poll_issue(struct io_kiocb *req, io_tw_token_t tw);
 int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr);
 int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin);
 __cold void io_iopoll_try_reap_events(struct io_ring_ctx *ctx);
diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c
index 7b25dcd9d05f..5525267d2e03 100644
--- a/io_uring/uring_cmd.c
+++ b/io_uring/uring_cmd.c
@@ -324,11 +324,11 @@ EXPORT_SYMBOL_GPL(io_uring_cmd_import_fixed_vec);
 
 void io_uring_cmd_issue_blocking(struct io_uring_cmd *ioucmd)
 {
 	struct io_kiocb *req = cmd_to_io_kiocb(ioucmd);
 
-	io_req_queue_iowq(req);
+	io_queue_iowq(req);
 }
 
 int io_cmd_poll_multishot(struct io_uring_cmd *cmd,
 			  unsigned int issue_flags, __poll_t mask)
 {
-- 
2.54.0