linux-kernel - Re: Re: [PATCH 2/2] [BUGFIX] virtio/console: Add pipe_lock/unlock for splice

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Message-ID: <51E8D2C3.80600@hitachi.com>
Date:	Fri, 19 Jul 2013 14:46:43 +0900
From:	Yoshihiro YUNOMAE <yoshihiro.yunomae.ez@...achi.com>
To:	Amit Shah <amit.shah@...hat.com>
Cc:	linux-kernel@...r.kernel.org,
	Hidehiro Kawai <hidehiro.kawai.ez@...achi.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
	Arnd Bergmann <arnd@...db.de>, yrl.pp-manager.tt@...achi.com
Subject: Re: Re: [PATCH 2/2] [BUGFIX] virtio/console: Add pipe_lock/unlock
 for splice_write

Hi Amit,

(2013/07/19 14:23), Amit Shah wrote:
> On (Fri) 19 Jul 2013 [08:19:32], Yoshihiro YUNOMAE wrote:
>> Add pipe_lock/unlock for splice_write to avoid oops by following competition:
>
>> diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
>> index 8722656..4a28e4c 100644
>> --- a/drivers/char/virtio_console.c
>> +++ b/drivers/char/virtio_console.c
>> @@ -936,6 +936,7 @@ static ssize_t port_fops_splice_write(struct pipe_inode_info *pipe,
>>   	 * pipe->nrbufs == 0 means there are no data to transfer,
>>   	 * so this returns just 0 for no data.
>>   	 */
>> +	pipe_lock(pipe);
>>   	if (!pipe->nrbufs)
>>   		return 0;
>>
>> @@ -953,6 +954,7 @@ static ssize_t port_fops_splice_write(struct pipe_inode_info *pipe,
>>   	sgl.sg = buf->sg;
>>   	sg_init_table(sgl.sg, sgl.size);
>>   	ret = __splice_from_pipe(pipe, &sd, pipe_to_sg);
>> +	pipe_unlock(pipe);
>>   	if (likely(ret > 0))
>>   		ret = __send_to_port(port, buf->sg, sgl.n, sgl.len, buf, true);
>>
>>
>
> You're not unlocking in all the error return cases.

Oh, sorry.
I'll resend a revised patch soon.
Thanks!

Yoshihiro YUNOMAE

-- 
###2013.03.18より変更###
-------------------------------------------------
湯前　慶大（YUNOMAE Yoshihiro）
（株）日立製作所　横浜研究所
ソフトウェアプラットフォーム研究部 PP3u & LTC
e-mail: yoshihiro.yunomae.ez@...achi.com
内線PHS: 874-2583
外線PHS: 050-3135-2583
-------------------------------------------------
Yoshihiro YUNOMAE
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: yoshihiro.yunomae.ez@...achi.com


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