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Date:   Mon, 11 Mar 2019 20:44:31 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     Al Viro <viro@ZenIV.linux.org.uk>
Cc:     Linus Torvalds <torvalds@linux-foundation.org>,
        Eric Dumazet <eric.dumazet@gmail.com>,
        David Miller <davem@davemloft.net>,
        Jason Baron <jbaron@akamai.com>, kgraul@linux.ibm.com,
        ktkhai@virtuozzo.com, kyeongdon.kim@lge.com,
        Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
        Netdev <netdev@vger.kernel.org>, pabeni@redhat.com,
        syzkaller-bugs@googlegroups.com, xiyou.wangcong@gmail.com,
        Christoph Hellwig <hch@lst.de>,
        zhengbin <zhengbin13@huawei.com>, bcrl@kvack.org,
        linux-fsdevel@vger.kernel.org, linux-aio@kvack.org,
        houtao1@huawei.com, yi.zhang@huawei.com
Subject: Re: [PATCH 3/8] aio: store event at final iocb_put()
Message-ID: <20190311194431.GD12602@lst.de>
References: <20190310070606.GA10138@ZenIV.linux.org.uk> <20190310070822.11564-1-viro@ZenIV.linux.org.uk> <20190310070822.11564-3-viro@ZenIV.linux.org.uk>
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On Sun, Mar 10, 2019 at 07:08:17AM +0000, Al Viro wrote:
> From: Al Viro <viro@zeniv.linux.org.uk>
> 
> Instead of having aio_complete() set ->ki_res.{res,res2}, do that
> explicitly in its callers, drop the reference (as aio_complete()
> used to do) and delay the rest until the final iocb_put().
> 
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
> ---
>  fs/aio.c | 45 ++++++++++++++++++++-------------------------
>  1 file changed, 20 insertions(+), 25 deletions(-)
> 
> diff --git a/fs/aio.c b/fs/aio.c
> index 2249a7a1d6b3..b9c4c1894020 100644
> --- a/fs/aio.c
> +++ b/fs/aio.c
> @@ -1077,24 +1077,10 @@ static inline void iocb_destroy(struct aio_kiocb *iocb)
>  	kmem_cache_free(kiocb_cachep, iocb);
>  }
>  
> -static inline void iocb_put(struct aio_kiocb *iocb)
> -{
> -	if (refcount_dec_and_test(&iocb->ki_refcnt))
> -		iocb_destroy(iocb);
> -}

Maybe iocb_put should just have been added in the place you move
it to in patch 1?