Re: [PATCH] io_uring: add IORING_OP_NOP_FAIL

[Ming Lei <ming.lei@redhat.com>]

On Wed, May 08, 2024 at 08:55:09PM -0600, Jens Axboe wrote:
> On 5/8/24 8:34 PM, Ming Lei wrote:
> > Add IORING_OP_NOP_FAIL so that it is easy to inject failure from
> > userspace.
> > 
> > Like IORING_OP_NOP, the main use case is test, and it is very helpful
> > for covering failure handling code in io_uring core change.
> 
> Rather than use a new opcode for this, why don't we just add it to
> the existing NOP? I know we don't check for flags in currently, so
> you would not know if it worked, but we could add that and just
> backport that one-liner as well.

Yeah, it is just for avoiding to break existed tests which may not build
over liburing.

I will switch to this way, looks one-line backporting can solve it.

> And if we had such a flag, the fail res could be passed in as well.

We can just pass the 'injected_fail_res' via sqe->len, meantime keep
'nop_flags' for error injection and future extension.


thanks,
Ming