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>

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index bdb7e15f1c48572e4ef45a58923a6e6344f562e6..cf68d16255a0ebc1d58655ade0f2cd1063578439 100644 (file)
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -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);

diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index 55d4ab96fb9255706d915c1c0cc2bdcf2abd9999..187f1c83e7798ab3c58ace2b7a9a105bfad9e3cf 100644 (file)
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -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;