[PATCH 1/2] ravb: kill redundant check in the probe() method

[PATCH 1/2] ravb: kill redundant check in the probe() method

[Sergei Shtylyov]

[-- Attachment #1: ravb-kill-redundant-check-in-the-probe-method.patch --]
[-- Type: text/plain, Size: 901 bytes --]

Browsing thru the driver diassembly, I noticed that gcc was  able to
figure  out  that the 'ndev' pointer is always non-NULL when calling
free_netdev()  on the probe() method's  error path and  thus skip that
redundant NULL check... gcc is smart, be like gcc! :-)

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>

---
 drivers/net/ethernet/renesas/ravb_main.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Index: net-next/drivers/net/ethernet/renesas/ravb_main.c
===================================================================
--- net-next.orig/drivers/net/ethernet/renesas/ravb_main.c
+++ net-next/drivers/net/ethernet/renesas/ravb_main.c
@@ -2205,8 +2205,7 @@ out_dma_free:
 	if (chip_id != RCAR_GEN2)
 		ravb_ptp_stop(ndev);
 out_release:
-	if (ndev)
-		free_netdev(ndev);
+	free_netdev(ndev);
 
 	pm_runtime_put(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);

Re: [PATCH 1/2] ravb: kill redundant check in the probe() method

[Geert Uytterhoeven]

Hi Sergei,

On Sun, Dec 31, 2017 at 7:41 PM, Sergei Shtylyov
<sergei.shtylyov@cogentembedded.com> wrote:
> Browsing thru the driver diassembly, I noticed that gcc was  able to
> figure  out  that the 'ndev' pointer is always non-NULL when calling
> free_netdev()  on the probe() method's  error path and  thus skip that
> redundant NULL check... gcc is smart, be like gcc! :-)

Thanks for your patch!

> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

> --- net-next.orig/drivers/net/ethernet/renesas/ravb_main.c
> +++ net-next/drivers/net/ethernet/renesas/ravb_main.c
> @@ -2205,8 +2205,7 @@ out_dma_free:
>         if (chip_id != RCAR_GEN2)
>                 ravb_ptp_stop(ndev);
>  out_release:
> -       if (ndev)
> -               free_netdev(ndev);
> +       free_netdev(ndev);
>
>         pm_runtime_put(&pdev->dev);
>         pm_runtime_disable(&pdev->dev);

BTW, there isn't a functional dependency, but you may want to move the
freeing of the netdev below disabling of Runtime PM for symmetry (use
reverse order in cleanup).

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH 1/2] ravb: kill redundant check in the probe() method

[Geert Uytterhoeven]

Hi Sergei,

On Sun, Dec 31, 2017 at 7:41 PM, Sergei Shtylyov
<sergei.shtylyov@cogentembedded.com> wrote:
> Browsing thru the driver diassembly, I noticed that gcc was  able to
> figure  out  that the 'ndev' pointer is always non-NULL when calling
> free_netdev()  on the probe() method's  error path and  thus skip that
> redundant NULL check... gcc is smart, be like gcc! :-)

Thanks for your patch!

> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

> --- net-next.orig/drivers/net/ethernet/renesas/ravb_main.c
> +++ net-next/drivers/net/ethernet/renesas/ravb_main.c
> @@ -2205,8 +2205,7 @@ out_dma_free:
>         if (chip_id != RCAR_GEN2)
>                 ravb_ptp_stop(ndev);
>  out_release:
> -       if (ndev)
> -               free_netdev(ndev);
> +       free_netdev(ndev);
>
>         pm_runtime_put(&pdev->dev);
>         pm_runtime_disable(&pdev->dev);

BTW, there isn't a functional dependency, but you may want to move the
freeing of the netdev below disabling of Runtime PM for symmetry (use
reverse order in cleanup).

Gr{oetje,eeting}s,

                        Geert

Re: [PATCH 1/2] ravb: kill redundant check in the probe() method

[Sergei Shtylyov]

Hello!

On 12/31/2017 9:41 PM, Sergei Shtylyov wrote:

> Browsing thru the driver diassembly, I noticed that gcc was  able to

    Aw, it's disassembly!
    DaveM, is that worth reposting?

> figure  out  that the 'ndev' pointer is always non-NULL when calling
> free_netdev()  on the probe() method's  error path and  thus skip that
> redundant NULL check... gcc is smart, be like gcc! 
> 
> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
[...]

MBR, Sergei