Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Sun, 3 Feb 2019 09:26:45 +0100
From:   Boris Brezillon <bbrezillon@kernel.org>
To:     Liu Jian <liujian56@huawei.com>
Cc:     <dwmw2@infradead.org>, <computersforpeace@gmail.com>,
        <marek.vasut@gmail.com>, <richard@nod.at>,
        <joakim.tjernlund@infinera.com>, <ikegami@allied-telesis.co.jp>,
        <keescook@chromium.org>, <linux-mtd@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>,
        Przemyslaw Sobon <psobon@amazon.com>
Subject: Re: [PATCH] cfi: fix deadloop in cfi_cmdset_0002.c do_write_buffer
Message-ID: <20190203092645.18d1495b@bbrezillon>
In-Reply-To: <1548977439-318904-1-git-send-email-liujian56@huawei.com>
References: <1548977439-318904-1-git-send-email-liujian56@huawei.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

+Przemyslaw

On Fri, 1 Feb 2019 07:30:39 +0800
Liu Jian <liujian56@huawei.com> wrote:

> In function do_write_buffer(), in the for loop, there is a case
> chip_ready() returns 1 while chip_good() returns 0, so it never
> break the loop.
> To fix this, chip_good() is enough and it should timeout if it stay
> bad for a while.

Looks like Przemyslaw reported and fixed the same problem.

> 
> Fixes: dfeae1073583(mtd: cfi_cmdset_0002: Change write buffer to check
> correct value)

Can you put the Fixes tag on a single, and the format is

Fixes: <hash> ("message")

> Signed-off-by: Yi Huaijie <yihuaijie@huawei.com>
> Signed-off-by: Liu Jian <liujian56@huawei.com>

[1]http://patchwork.ozlabs.org/patch/1025566/

> ---
>  drivers/mtd/chips/cfi_cmdset_0002.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mtd/chips/cfi_cmdset_0002.c b/drivers/mtd/chips/cfi_cmdset_0002.c
> index 72428b6..818e94b 100644
> --- a/drivers/mtd/chips/cfi_cmdset_0002.c
> +++ b/drivers/mtd/chips/cfi_cmdset_0002.c
> @@ -1876,14 +1876,14 @@ static int __xipram do_write_buffer(struct map_info *map, struct flchip *chip,
>  			continue;
>  		}
>  
> -		if (time_after(jiffies, timeo) && !chip_ready(map, adr))
> -			break;
> -
>  		if (chip_good(map, adr, datum)) {
>  			xip_enable(map, chip, adr);
>  			goto op_done;
>  		}
>  
> +		if (time_after(jiffies, timeo))
> +			break;
> +
>  		/* Latency issues. Drop the lock, wait a while and retry */
>  		UDELAY(map, chip, adr, 1);
>  	}