From: Jens Axboe <axboe@kernel.dk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
io-uring <io-uring@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: namei.c LOOKUP_NONBLOCK (was "Re: [GIT PULL] io_uring fixes for 5.10-rc")
Date: Thu, 10 Dec 2020 12:21:28 -0700 [thread overview]
Message-ID: <4790c746-0911-0bde-06fb-c987d6b0c3af@kernel.dk> (raw)
In-Reply-To: <CAHk-=wicKF87YsiQpdK0B26Mk3UhRNrBEcOv7h=ohFKLjRM4DQ@mail.gmail.com>
On 12/10/20 11:55 AM, Linus Torvalds wrote:
> On Thu, Dec 10, 2020 at 9:32 AM Jens Axboe <axboe@kernel.dk> wrote:
>>
>> Here's a potentially better attempt - basically we allow LOOKUP_NONBLOCK
>> with LOOKUP_RCU, and if we end up dropping LOOKUP_RCU, then we generally
>> return -EAGAIN if LOOKUP_NONBLOCK is set as we can no longer guarantee
>> that we won't block.
>
> Looks sane to me.
>
> I don't love the "__unlazy_walk vs unlazy_walk" naming - I think it
> needs to be more clear about what the difference is, but I think the
> basic patch looks sane, and looks about as big as I would have
> expected it to be.
Agree, would probably make more sense as __unlazy_walk ->
complete_walk_rcu(), which then also falls out naturally from
complete_walk() being the sole caller of that.
> But yes, I'll leave it to Al.
>
> And if we do this - and I think we should - I'd also love to see a new
> flag in 'struct open_how' to openat2(), even if it's only to enable
> tests. RESOLVE_NONBLOCK?
Sure, enabling cached opens from userspace through regular openat2().
Let's wrap up this one first though, that needs to be a separate patch
anyway. I'll follow up with that once this is in.
--
Jens Axboe
next prev parent reply other threads:[~2020-12-10 19:22 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-20 18:45 [GIT PULL] io_uring fixes for 5.10-rc Jens Axboe
2020-11-20 20:02 ` Linus Torvalds
2020-11-20 21:36 ` Jens Axboe
2020-11-21 0:23 ` Linus Torvalds
2020-11-21 2:41 ` Jens Axboe
2020-11-21 3:00 ` Jens Axboe
2020-11-21 18:07 ` Linus Torvalds
2020-11-21 22:58 ` Jens Axboe
2020-12-10 17:32 ` namei.c LOOKUP_NONBLOCK (was "Re: [GIT PULL] io_uring fixes for 5.10-rc") Jens Axboe
2020-12-10 18:55 ` Linus Torvalds
2020-12-10 19:21 ` Jens Axboe [this message]
2020-11-21 0:29 ` [GIT PULL] io_uring fixes for 5.10-rc pr-tracker-bot
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