From: Jeff Moyer <jmoyer@redhat.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: "linux-fsdevel\@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"linux-block\@vger.kernel.org" <linux-block@vger.kernel.org>,
linux-aio@kvack.org
Subject: Re: [PATCH] fs: kill unused ret2 argument from iocb->ki_complete()
Date: Wed, 20 Oct 2021 14:16:19 -0400 [thread overview]
Message-ID: <x498ryno93g.fsf@segfault.boston.devel.redhat.com> (raw)
In-Reply-To: <ce839d66-1d05-dab8-4540-71b8485fdaf3@kernel.dk> (Jens Axboe's message of "Wed, 20 Oct 2021 10:49:07 -0600")
Hi, Jens,
Jens Axboe <axboe@kernel.dk> writes:
> It's not used for anything, and we're wasting time passing in zeroes
> where we could just ignore it instead. Update all ki_complete users in
> the kernel to drop that last argument.
What does "wasting time passing in zeroes" mean?
> The exception is the USB gadget code, which passes in non-zero. But
> since nobody every looks at ret2, it's still pointless.
As Christoph mentioned, it is passed along to userspace as part of the
io_event.
> @@ -499,8 +499,7 @@ static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req)
> /* aio_complete() reports bytes-transferred _and_ faults */
Note this comment ^^^
>
> iocb->ki_complete(iocb,
> - req->actual ? req->actual : (long)req->status,
> - req->status);
> + req->actual ? req->actual : (long)req->status);
We can't know whether some userspace implementation relies on this
behavior, so I don't think you can change it.
Cheers,
Jeff
p.s. Please CC linux-aio on future changes to the aio code.
next prev parent reply other threads:[~2021-10-20 18:14 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-20 16:49 [PATCH] fs: kill unused ret2 argument from iocb->ki_complete() Jens Axboe
2021-10-20 17:30 ` Christoph Hellwig
2021-10-20 17:35 ` Jens Axboe
2021-10-20 17:49 ` Greg Kroah-Hartman
2021-10-21 16:40 ` John Keeping
2021-10-21 16:56 ` Jens Axboe
2021-10-22 15:44 ` Jens Axboe
2021-10-23 9:09 ` Greg Kroah-Hartman
2021-10-23 14:01 ` Jens Axboe
2021-10-20 18:16 ` Jeff Moyer [this message]
2021-10-20 18:21 ` Jens Axboe
2021-10-20 18:37 ` Jeff Moyer
2021-10-20 18:41 ` Jens Axboe
2021-10-20 18:56 ` Jens Axboe
2021-10-20 19:11 ` Jeff Moyer
2021-10-20 19:12 ` Jens Axboe
2021-10-20 19:47 ` Jeff Moyer
2021-10-20 19:54 ` Jens Axboe
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