Re: [PATCH v3 4/4] io_uring/uring_cmd: avoid double indirect call in task work dispatch

[Caleb Sander Mateos <csander@purestorage.com>]

On Mon, Oct 27, 2025 at 12:51 AM Christoph Hellwig <hch@lst.de> wrote:
>
> > +static void blk_cmd_complete(struct io_tw_req tw_req, io_tw_token_t tw)
> >  {
> > +     unsigned int issue_flags = IO_URING_CMD_TASK_WORK_ISSUE_FLAGS;
>
> In most of these ioctl handlers issue_flags only has a single user,
> so you might as well pass it directly.

Sure, happy to get rid of the intermediate variable in places where
issue_flags is only referenced once.

>
> In fact asm most external callers of io_uring_cmd_done pass that, would
> a helper that just harcodes it make sense and then maybe switch the
> special cases to use __io_uring_cmd_done directly?

While issue_flags is mainly used to pass to io_uring_cmd_done(), there
are some other uses too. For example, ublk_cmd_tw_cb() and
ublk_cmd_list_tw_cb() pass it to io_buffer_register_bvec() via
ublk_dispatch_req(), ublk_prep_auto_buf_reg(), and
ublk_auto_buf_reg(). Since uring_cmd implementations can perform
arbitrary work in task work context, I think it makes sense to keep
IO_URING_CMD_TASK_WORK_ISSUE_FLAG so it can be used wherever it's
required.

Best,
Caleb