Re: [PATCH] scsi: Delete an unnecessary check before the function call "kfree"

[Laurence Oberman]

----- Original Message -----
> From: "SF Markus Elfring" <elfring@xxxxxxxxxxxxxxxxxxxxx>
> To: linux-scsi@xxxxxxxxxxxxxxx, "Christoph Hellwig" <hch@xxxxxx>, "Hannes Reinecke" <hare@xxxxxxx>, "James E. J.
> Bottomley" <jejb@xxxxxxxxxxxxxxxxxx>, "Martin K. Petersen" <martin.petersen@xxxxxxxxxx>
> Cc: "LKML" <linux-kernel@xxxxxxxxxxxxxxx>, kernel-janitors@xxxxxxxxxxxxxxx, "Julia Lawall" <julia.lawall@xxxxxxx>
> Sent: Sunday, July 24, 2016 8:30:35 AM
> Subject: [PATCH] scsi: Delete an unnecessary check before the function call "kfree"
> 
> From: Markus Elfring <elfring@xxxxxxxxxxxxxxxxxxxxx>
> Date: Sun, 24 Jul 2016 14:20:21 +0200
> 
> The kfree() function tests whether its argument is NULL and then
> returns immediately. Thus the test around the call is not needed.
> 
> This issue was detected by using the Coccinelle software.
> 
> Signed-off-by: Markus Elfring <elfring@xxxxxxxxxxxxxxxxxxxxx>
> ---
>  drivers/scsi/scsi.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
> index 1f36aca..1794c0c 100644
> --- a/drivers/scsi/scsi.c
> +++ b/drivers/scsi/scsi.c
> @@ -864,8 +864,7 @@ retry_pg83:
>  		rcu_assign_pointer(sdev->vpd_pg83, vpd_buf);
>  		mutex_unlock(&sdev->inquiry_mutex);
>  		synchronize_rcu();
> -		if (orig_vpd_buf)
> -			kfree(orig_vpd_buf);
> +		kfree(orig_vpd_buf);
>  	}
>  }
>  
> --
> 2.9.2
> 
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Looks fine, small comment is that the function call prior to check in the fucntion sets up variables etc. 
So is more expensive than a simple NULL check prior.

Reviewed-by: Laurence Oberman <loberman@xxxxxxxxxx>