Re: [Outreachy kernel] [PATCH 3/5] staging: rtl8712: Remove unnecessary else after return

From: Julia Lawall
Date: Mon Feb 27 2017 - 20:03:41 EST




On Mon, 27 Feb 2017, simran singhal wrote:

> This patch fixes the checkpatch warning that else is not generally
> useful after a break or return.
>
> This was done using Coccinelle:
> @@
> expression e2;
> statement s1;
> @@
> if(e2) { ... return ...; }
> -else
> s1

One might be surprised that the following code was detected using the
above semantic patch, because in the code below there is no return in the
if branches. Actually, as a special feature, when one has an if branch
that ends in return, Coccinelle will skip through any gotos and see if the
return is matched afterward. Indeed it is a common pattern to have

if (...) {
foo(x);
bar(y);
return -ENOMEM;
}

But the code can also be cut up as eg

if (...) {
ret = -ENOMEM;
goto out;
}
...
out:
foo(x);
bar(y);
return ret;

To avoid having to write multiple patterns for these cases, Coccinelle
will just jump through the return in the second case, allowing the same
pattern to match both of them.

julia

>
> Signed-off-by: simran singhal <singhalsimran0@xxxxxxxxx>
> ---
> drivers/staging/rtl8712/os_intfs.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/drivers/staging/rtl8712/os_intfs.c b/drivers/staging/rtl8712/os_intfs.c
> index 8836b31..3062167 100644
> --- a/drivers/staging/rtl8712/os_intfs.c
> +++ b/drivers/staging/rtl8712/os_intfs.c
> @@ -411,8 +411,7 @@ static int netdev_open(struct net_device *pnetdev)
> goto netdev_open_error;
> if (!padapter->dvobjpriv.inirp_init)
> goto netdev_open_error;
> - else
> - padapter->dvobjpriv.inirp_init(padapter);
> + padapter->dvobjpriv.inirp_init(padapter);
> r8712_set_ps_mode(padapter, padapter->registrypriv.power_mgnt,
> padapter->registrypriv.smart_ps);
> }
> --
> 2.7.4
>
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