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Subject: Re: [PATCH] loop: Call loop_config_discard() only after new config is
 applied.
To:     Martijn Coenen <maco@android.com>, axboe@kernel.dk, hch@lst.de
Cc:     ming.lei@redhat.com, bvanassche@acm.org,
        Chaitanya.Kulkarni@wdc.com, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, kernel-team@android.com
References: <20200331114116.21642-1-maco@android.com>
From:   Bob Liu <bob.liu@oracle.com>
Message-ID: <fcdeb6a5-5da0-6759-3568-f5fa517e1c5d@oracle.com>
Date:   Fri, 17 Apr 2020 08:19:52 +0800
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On 3/31/20 7:41 PM, Martijn Coenen wrote:
> loop_set_status() calls loop_config_discard() to configure discard for
> the loop device; however, the discard configuration depends on whether
> the loop device uses encryption, and when we call it the encryption
> configuration has not been updated yet. Move the call down so we apply
> the correct discard configuration based on the new configuration.
> 
> Signed-off-by: Martijn Coenen <maco@android.com>

Looks fine to me.
Reviewed-by: Bob Liu <bob.liu@oracle.com>

> ---
>  drivers/block/loop.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index 739b372a5112..7c9dcb6007a6 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -1312,8 +1312,6 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
>  		}
>  	}
>  
> -	loop_config_discard(lo);
> -
>  	memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE);
>  	memcpy(lo->lo_crypt_name, info->lo_crypt_name, LO_NAME_SIZE);
>  	lo->lo_file_name[LO_NAME_SIZE-1] = 0;
> @@ -1337,6 +1335,8 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
>  		lo->lo_key_owner = uid;
>  	}
>  
> +	loop_config_discard(lo);
> +
>  	/* update dio if lo_offset or transfer is changed */
>  	__loop_update_dio(lo, lo->use_dio);
>  
>