Re: [PATCH] liquidio: lio_vf_main: remove unnecessary static in setup_io_queues()

From: Felix Manlunas
Date: Tue Jul 18 2017 - 17:05:17 EST


On Tue, Jul 18, 2017 at 03:50:15PM -0500, Gustavo A. R. Silva wrote:
> Remove unnecessary static on local variables cpu_id_modulus and cpu_id.
> Such variables are initialized before being used, on every execution
> path throughout the function. The static has no benefit and, removing
> it reduces the object file size.
>
> This issue was detected using Coccinelle and the following semantic patch:
>
> @bad exists@
> position p;
> identifier x;
> type T;
> @@
>
> static T x@p;
> ...
> x = <+...x...+>
>
> @@
> identifier x;
> expression e;
> type T;
> position p != bad.p;
> @@
>
> -static
> T x@p;
> ... when != x
> when strict
> ?x = e;
>
> In the following log you can see a significant difference in the object
> file size. Also, there is a significant difference in the bss segment.
> This log is the output of the size command, before and after the code
> change:
>
> before:
> text data bss dec hex filename
> 55656 10680 576 66912 10560 drivers/net/ethernet/cavium/liquidio/lio_vf_main.o
>
> after:
> text data bss dec hex filename
> 55796 10536 448 66780 104dc drivers/net/ethernet/cavium/liquidio/lio_vf_main.o
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
> ---
> drivers/net/ethernet/cavium/liquidio/lio_vf_main.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c b/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c
> index 9b24710..935ff29 100644
> --- a/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c
> +++ b/drivers/net/ethernet/cavium/liquidio/lio_vf_main.c
> @@ -1663,10 +1663,10 @@ static int setup_io_queues(struct octeon_device *octeon_dev, int ifidx)
> {
> struct octeon_droq_ops droq_ops;
> struct net_device *netdev;
> - static int cpu_id_modulus;
> + int cpu_id_modulus;
> struct octeon_droq *droq;
> struct napi_struct *napi;
> - static int cpu_id;
> + int cpu_id;
> int num_tx_descs;
> struct lio *lio;
> int retval = 0;
> --
> 2.5.0
>

Thanks.

Acked-by: Felix Manlunas <felix.manlunas@xxxxxxxxxx>