Re: [PATCH 5/5] null_blk: Zero-initialize read buffers in non-memory-backed mode

From: Bart Van Assche <bvanassche@acm.org>
To: Damien Le Moal <Damien.LeMoal@wdc.com>, Jens Axboe <axboe@kernel.dk>
Cc: "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
	Christoph Hellwig <hch@lst.de>, Ming Lei <ming.lei@redhat.com>,
	Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>,
	Alexander Potapenko <glider@google.com>
Subject: Re: [PATCH 5/5] null_blk: Zero-initialize read buffers in non-memory-backed mode
Date: Sun, 17 May 2020 18:32:48 -0700	[thread overview]
Message-ID: <440743f4-1053-32f3-2edf-3eb0fdd057ef@acm.org> (raw)
In-Reply-To: <BY5PR04MB69008A16B82CD028FC01D0A6E7B80@BY5PR04MB6900.namprd04.prod.outlook.com>

On 2020-05-17 18:12, Damien Le Moal wrote:
> On 2020/05/16 9:19, Bart Van Assche wrote:
>> +static void nullb_zero_rq_data_buffer(const struct request *rq)
>> +{
>> +	struct req_iterator iter;
>> +	struct bio_vec bvec;
>> +
>> +	rq_for_each_bvec(bvec, rq, iter)
>> +		zero_fill_bvec(&bvec);
>> +}
>> +
>> +static void nullb_zero_read_cmd_buffer(struct nullb_cmd *cmd)
>> +{
>> +	struct nullb_device *dev = cmd->nq->dev;
>> +
>> +	if (dev->queue_mode == NULL_Q_BIO && bio_op(cmd->bio) == REQ_OP_READ)
>> +		zero_fill_bio(cmd->bio);
>> +	else if (req_op(cmd->rq) == REQ_OP_READ)
>> +		nullb_zero_rq_data_buffer(cmd->rq);
>> +}
> 
> Shouldn't the definition of these two functions be under a "#ifdef CONFIG_KMSAN" ?

Hi Damien,

It is on purpose that I used IS_ENABLED(CONFIG_KMSAN) below instead of
#ifdef CONFIG_KMSAN. CONFIG_KMSAN is not yet upstream and I want to
expose the above code to the build robot.

Thanks,

Bart.