Re: [PATCH for-next 03/12] io_uring: support retargeting rsrc on requests in the io-wq

[Jens Axboe <axboe@kernel.dk>]

On 10/31/22 7:41 AM, Dylan Yudaken wrote:
> Requests can be in flight on the io-wq, and can be long lived (for example
> a double read will get onto the io-wq). So make sure to retarget the rsrc
> nodes on those requests.
> 
> Signed-off-by: Dylan Yudaken <dylany@meta.com>
> ---
>  io_uring/rsrc.c | 46 ++++++++++++++++++++++++++++++++++++++++++----
>  1 file changed, 42 insertions(+), 4 deletions(-)
> 
> diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
> index 106210e0d5d5..8d0d40713a63 100644
> --- a/io_uring/rsrc.c
> +++ b/io_uring/rsrc.c
> @@ -16,6 +16,7 @@
>  #include "openclose.h"
>  #include "rsrc.h"
>  #include "opdef.h"
> +#include "tctx.h"
>  
>  struct io_rsrc_update {
>  	struct file			*file;
> @@ -24,6 +25,11 @@ struct io_rsrc_update {
>  	u32				offset;
>  };
>  
> +struct io_retarget_data {
> +	struct io_ring_ctx		*ctx;
> +	unsigned int			refs;
> +};

Do we really need this struct? As far as I can tell, you pass in ctx
only and back refs. It's passed in the callbacks, but they only care
about ctx. If io_rsrc_retarget_wq() returned back the refs rather than
use data->refs, then we could just pass in the ctx?

Or you could at least keep it local to io_rsrc_retarget_wq() and
io_retarget_rsrc_wq_cb().

Not a big deal, just always nice to keep the scope of struct as small as
can be (or get rid of them).

-- 
Jens Axboe