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From: Matthew Wilcox <willy@infradead.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
	Benjamin LaHaise <bcrl@kvack.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Kees Cook <keescook@chromium.org>,
	fsdevel <linux-fsdevel@vger.kernel.org>,
	linux-aio@kvack.org, linux-mm <linux-mm@kvack.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Dan Carpenter <dan.carpenter@oracle.com>
Subject: Re: [PATCH] aio: Convert ioctx_table to XArray
Date: Tue, 11 Dec 2018 10:53:11 -0800	[thread overview]
Message-ID: <20181211185311.GJ6830@bombadil.infradead.org> (raw)
In-Reply-To: <75267003-9407-101f-33ee-685e345a2c8a@kernel.dk>

On Tue, Dec 11, 2018 at 11:46:53AM -0700, Jens Axboe wrote:
> On 12/11/18 11:45 AM, Matthew Wilcox wrote:
> > I think we need the rcu read lock here to prevent ctx from being freed
> > under us by free_ioctx().
> 
> Then that begs the question, how about __xa_load() that is already called
> under RCU read lock?

I've been considering adding it to the API, yes.  I was under the
impression that nested rcu_read_lock() calls were not expensive, even
with CONFIG_PREEMPT.

  reply	other threads:[~2018-12-11 18:53 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-28 18:35 [PATCH] aio: Convert ioctx_table to XArray Matthew Wilcox
2018-12-06 21:08 ` Matthew Wilcox
2018-12-06 22:21 ` Jeff Moyer
2018-12-06 22:21   ` Jeff Moyer
2018-12-06 22:26   ` Jeff Moyer
2018-12-06 22:26     ` Jeff Moyer
2018-12-11 17:21     ` Jeff Moyer
2018-12-11 17:21       ` Jeff Moyer
2018-12-11 17:51       ` Matthew Wilcox
2018-12-11 18:02         ` Jeff Moyer
2018-12-11 18:02           ` Jeff Moyer
2018-12-11 18:05           ` Jens Axboe
2018-12-11 18:09             ` Jeff Moyer
2018-12-11 18:09               ` Jeff Moyer
2018-12-11 18:37               ` Jens Axboe
2018-12-11 18:32             ` Jens Axboe
2018-12-11 18:36               ` Jens Axboe
2018-12-11 18:51               ` Matthew Wilcox
2018-12-11 18:52                 ` Jens Axboe
2018-12-11 18:41 ` Jens Axboe
2018-12-11 18:41   ` Jens Axboe
2018-12-11 18:45   ` Matthew Wilcox
2018-12-11 18:46     ` Jens Axboe
2018-12-11 18:53       ` Matthew Wilcox [this message]
2018-12-11 18:54         ` Jens Axboe
2018-12-11 18:53       ` Jens Axboe

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