linux-kernel - Re: [PATCH 30/33] block, aio: batch completion for bios/kiocbs

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Message-ID: <20130402194803.GA5703@thunk.org>
Date:	Tue, 2 Apr 2013 15:48:03 -0400
From:	Theodore Ts'o <tytso@....edu>
To:	Kent Overstreet <koverstreet@...gle.com>
Cc:	linux-kernel@...r.kernel.org, linux-aio@...ck.org,
	akpm@...ux-foundation.org, Zach Brown <zab@...hat.com>,
	Felipe Balbi <balbi@...com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Mark Fasheh <mfasheh@...e.com>,
	Joel Becker <jlbec@...lplan.org>,
	Rusty Russell <rusty@...tcorp.com.au>,
	Jens Axboe <axboe@...nel.dk>,
	Asai Thambi S P <asamymuthupa@...ron.com>,
	Selvan Mani <smani@...ron.com>,
	Sam Bradshaw <sbradshaw@...ron.com>,
	Jeff Moyer <jmoyer@...hat.com>,
	Al Viro <viro@...iv.linux.org.uk>,
	Benjamin LaHaise <bcrl@...ck.org>,
	Minchan Kim <minchan@...nel.org>
Subject: Re: [PATCH 30/33] block, aio: batch completion for bios/kiocbs

On Thu, Mar 21, 2013 at 09:35:51AM -0700, Kent Overstreet wrote:
> +		if (unlikely(req->ki_ctx != ctx)) {
> +			kioctx_ring_unlock(ctx, tail);
> +
> +			ctx = req->ki_ctx;
> +			tail = kioctx_ring_lock(ctx);
> +		}

The only place where you're calling kioctx_ring_lock() is above, which
is part of an unlock/lock pair.

There is also a kioctx_ring_unlock at the end of batch_complete_aio():

> +	kioctx_ring_unlock(ctx, tail);
> +	local_irq_restore(flags);
> +	rcu_read_unlock();

But I'm not seeing a matching kioctx_ring_lock() before the while loop
in batch_complete_aio(), nor anywhere else in the file.  And since
kioctx_ring_lock() is a static function....

Am I missing something?

						- Ted
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