From: Jens Axboe <axboe@kernel.dk>
To: Benny Halevy <bhalevy@scylladb.com>,
linux-block@vger.kernel.org, linux-aio@kvack.org,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 3/8] iomap/xfs: wire up file_operations ->iopoll()
Date: Wed, 21 Nov 2018 06:27:25 -0700 [thread overview]
Message-ID: <62aca28d-fd54-ae4e-d4d4-44c7232f23da@kernel.dk> (raw)
In-Reply-To: <feffd542a50966c7cd552c280290f406ea5629ef.camel@scylladb.com>
On 11/21/18 2:15 AM, Benny Halevy wrote:
>> +int iomap_dio_iopoll(struct kiocb *kiocb, bool spin)
>> +{
>> + struct iomap_dio *dio = kiocb->private;
>> + struct request_queue *q = READ_ONCE(dio->last_queue);
>> +
>> + if (!q || dio->cookie == BLK_QC_T_NONE)
>> + return 0;
>> + return blk_poll(q, READ_ONCE(dio->cookie), spin);
>
> How about:
> blk_qc_t cookie = READ_ONCE(dio->cookie);
>
> if (!q || cookie == BLK_QC_T_NONE)
> return 0;
> return blk_poll(q, cookie, spin);
>
> Is there a chance the dio->cookie in the if () condition
> will be stale?
I've rewritten this one, more importantly it needs to guard against
submission by ensuring that 'dio' is valid.
--
Jens Axboe
next prev parent reply other threads:[~2018-11-22 0:01 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-20 17:19 [PATCHSET v2] Support for polled aio Jens Axboe
2018-11-20 17:19 ` [PATCH 1/8] fs: add file_operations ->iopoll() handler Jens Axboe
2018-11-20 17:19 ` [PATCH 2/8] block: wire up block device ->iopoll() Jens Axboe
2018-11-20 17:19 ` [PATCH 3/8] iomap/xfs: wire up file_operations ->iopoll() Jens Axboe
2018-11-21 9:15 ` Benny Halevy
2018-11-21 13:27 ` Jens Axboe [this message]
2018-11-20 17:19 ` [PATCH 4/8] aio: use assigned completion handler Jens Axboe
2018-11-20 17:19 ` [PATCH 5/8] aio: fix failure to put the file pointer Jens Axboe
2018-11-20 17:19 ` [PATCH 6/8] aio: add io_setup2() system call Jens Axboe
2018-11-20 17:19 ` [PATCH 7/8] aio: separate out ring reservation from req allocation Jens Axboe
2018-11-20 17:19 ` [PATCH 8/8] aio: support for IO polling Jens Axboe
2018-11-21 11:12 ` Benny Halevy
2018-11-21 13:26 ` Jens Axboe
2018-11-21 13:51 ` Benny Halevy
2018-11-22 11:13 ` Jan Kara
2018-11-22 21:01 ` Jens Axboe
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