linux-kernel - Re: [PATCH] scsi: Fix incorrect usage of shost_for_each

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Message-ID: <c772dacb-b16a-e404-4333-ab5abf6daaf9@suse.de>
Date:   Thu, 4 Jun 2020 08:05:56 +0200
From:   Hannes Reinecke <hare@...e.de>
To:     Ye Bin <yebin10@...wei.com>, martin.petersen@...cle.com,
        jejb@...ux.ibm.com
Cc:     linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] scsi: Fix incorrect usage of shost_for_each_device

On 5/18/20 9:44 AM, Ye Bin wrote:
> shost_for_each_device(sdev, shost) \
> 	for ((sdev) = __scsi_iterate_devices((shost), NULL); \
> 	     (sdev); \
> 	     (sdev) = __scsi_iterate_devices((shost), (sdev)))
> 
> When terminating shost_for_each_device() iteration with break or return,
> scsi_device_put() should be used to prevent stale scsi device references from
> being left behind.
> 
> Signed-off-by: Ye Bin <yebin10@...wei.com>
> ---
>   drivers/scsi/scsi_error.c | 2 ++
>   drivers/scsi/scsi_lib.c   | 4 +++-
>   2 files changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
> index 978be1602f71..927b1e641842 100644
> --- a/drivers/scsi/scsi_error.c
> +++ b/drivers/scsi/scsi_error.c
> @@ -1412,6 +1412,7 @@ static int scsi_eh_stu(struct Scsi_Host *shost,
>   				sdev_printk(KERN_INFO, sdev,
>   					    "%s: skip START_UNIT, past eh deadline\n",
>   					    current->comm));
> +			scsi_device_put(sdev);
>   			break;
>   		}
>   		stu_scmd = NULL;
> @@ -1478,6 +1479,7 @@ static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
>   				sdev_printk(KERN_INFO, sdev,
>   					    "%s: skip BDR, past eh deadline\n",
>   					     current->comm));
> +			scsi_device_put(sdev);
>   			break;
>   		}
>   		bdr_scmd = NULL;
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index be1a4a9a5fca..173bc7fc2836 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -2859,8 +2859,10 @@ scsi_host_unblock(struct Scsi_Host *shost, int new_state)
>   
>   	shost_for_each_device(sdev, shost) {
>   		ret = scsi_internal_device_unblock(sdev, new_state);
> -		if (ret)
> +		if (ret) {
> +			scsi_device_put(sdev);
>   			break;
> +		}
>   	}
>   	return ret;
>   }
> 
Reviewed-by: Hannes Reinecke <hare@...e.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke            Teamlead Storage & Networking
hare@...e.de                               +49 911 74053 688
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