Commit ef67fcb4 authored by Dylan Yudaken's avatar Dylan Yudaken Committed by Jens Axboe
Browse files

io_uring: do not always force run task_work in io_uring_register 



Running task work when not needed can unnecessarily delay
operations. Specifically IORING_SETUP_DEFER_TASKRUN tries to avoid running
task work until the user requests it. Therefore do not run it in
io_uring_register any more.

The one catch is that io_rsrc_ref_quiesce expects it to have run in order
to process all outstanding references, and so reorder it's loop to do this.

Signed-off-by: default avatarDylan Yudaken <dylany@meta.com>
Link: https://lore.kernel.org/r/20221107123349.4106213-1-dylany@meta.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent df730ec2

io_uring/io_uring.c

+0 −2
Original line number Diff line number Diff line
@@ -4056,8 +4056,6 @@ SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode, 


	ctx = f.file->private_data;



	io_run_task_work_ctx(ctx);



	mutex_lock(&ctx->uring_lock);

	ret = __io_uring_register(ctx, opcode, arg, nr_args);

	mutex_unlock(&ctx->uring_lock);

io_uring/rsrc.c

+6 −1
Original line number Diff line number Diff line
@@ -321,6 +321,11 @@ __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data, 
		if (atomic_dec_and_test(&data->refs))

			break;

		mutex_unlock(&ctx->uring_lock);



		ret = io_run_task_work_sig(ctx);

		if (ret < 0)

			goto reinit;



		flush_delayed_work(&ctx->rsrc_put_work);

		ret = wait_for_completion_interruptible(&data->done);

		if (!ret) {
@@ -336,12 +341,12 @@ __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data, 
			}

		}



reinit:

		atomic_inc(&data->refs);

		/* wait for all works potentially completing data->done */

		flush_delayed_work(&ctx->rsrc_put_work);

		reinit_completion(&data->done);



		ret = io_run_task_work_sig(ctx);

		mutex_lock(&ctx->uring_lock);

	} while (ret >= 0);

	data->quiesce = false;