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: Dylan Yudaken <dylany@meta.com>
Link: https://lore.kernel.org/r/20221107123349.4106213-1-dylany@meta.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Dylan Yudaken 2022-11-07 04:33:49 -08:00 committed by Jens Axboe
parent df730ec21f
commit ef67fcb41d
2 changed files with 6 additions and 3 deletions

View File

@ -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);

View File

@ -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;