Subject: Re: [PATCH] vhost: scsi: constify target_core_fabric_ops structures

From: "Michael S. Tsirkin" <[email-masked]>
Date: Tue, 10 Jan 2017 07:11:40 +0200

On Mon, Jan 09, 2017 at 08:51:02PM +0530, Bhumika Goyal wrote:
> Declare target_core_fabric_ops strucrues as const as they are only
> passed as an argument to the functions target_register_template and 
> target_unregister_template. The arguments are of type const struct 
> target_core_fabric_ops *, so target_core_fabric_ops structures having 
> this property can be declared const.
> Done using Coccinelle:
> 
> @r disable optional_qualifier@
> identifier i;
> position p;
> @@
> static struct target_core_fabric_ops i@p={...};
> 
> @ok@
> position p;
> identifier r.i;
> @@
> (
> target_register_template(&i@p)
> |
> target_unregister_template(&i@p)
> )
> @bad@
> position p!={r.p,ok.p};
> identifier r.i;
> @@
> i@p
> 
> @depends on !bad disable optional_qualifier@
> identifier r.i;
> @@
> +const
> struct target_core_fabric_ops i;
> 
> File size before: drivers/vhost/scsi.o
>    text	   data	    bss	    dec	    hex	filename
>   18063	   2985	     40	  21088	   5260	drivers/vhost/scsi.o
> 
> File size after: drivers/vhost/scsi.o
>    text	   data	    bss	    dec	    hex	filename
>   18479	   2601	     40	  21120	   5280	drivers/vhost/scsi.o

What are these numbers trying to prove?

> Signed-off-by: Bhumika Goyal <[email-masked]>
> ---
>  drivers/vhost/scsi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
> index 253310c..620366d 100644
> --- a/drivers/vhost/scsi.c
> +++ b/drivers/vhost/scsi.c
> @@ -2087,7 +2087,7 @@ static void vhost_scsi_drop_tport(struct se_wwn *wwn)
>  	NULL,
>  };
>  
> -static struct target_core_fabric_ops vhost_scsi_ops = {
> +static const struct target_core_fabric_ops vhost_scsi_ops = {
>  	.module				= THIS_MODULE,
>  	.name				= "vhost",
>  	.get_fabric_name		= vhost_scsi_get_fabric_name,

If it can be const it probably should ...

> -- 
> 1.9.1