[PATCH 5/5] arch/um: remove duplicate structure field initialization

[PATCH 5/5] arch/um: remove duplicate structure field initialization

[Julia Lawall]

From: Julia Lawall <julia@diku.dk>

The definition of uml_netdev_ops has initializations of a local function
and eth_mac_addr for its ndo_set_mac_address field.  This change uses only
the local function.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r@
identifier I, s, fld;
position p0,p;
expression E;
@@

struct I s =@p0 { ... .fld@p = E, ...};

@s@
identifier I, s, r.fld;
position r.p0,p;
expression E;
@@

struct I s =@p0 { ... .fld@p = E, ...};

@script:python@
p0 << r.p0;
fld << r.fld;
ps << s.p;
pr << r.p;
@@

if int(ps[0].line)!=int(pr[0].line) or int(ps[0].column)!=int(pr[0].column):
  cocci.print_main(fld,p0)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>

---
 arch/um/drivers/net_kern.c          |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)

diff --git a/arch/um/drivers/net_kern.c b/arch/um/drivers/net_kern.c
index a74245a..d17a623 100644
--- a/arch/um/drivers/net_kern.c
+++ b/arch/um/drivers/net_kern.c
@@ -379,7 +379,6 @@ static const struct net_device_ops uml_netdev_ops = {
 	.ndo_tx_timeout 	= uml_net_tx_timeout,
 	.ndo_set_mac_address	= uml_net_set_mac,
 	.ndo_change_mtu 	= uml_net_change_mtu,
-	.ndo_set_mac_address 	= eth_mac_addr,
 	.ndo_validate_addr	= eth_validate_addr,
 };
 

Re: [PATCH 5/5] arch/um: remove duplicate structure field initialization

[Américo Wang]

On Sat, Sep 19, 2009 at 09:49:47PM +0200, Julia Lawall wrote:
>From: Julia Lawall <julia@diku.dk>
>
>The definition of uml_netdev_ops has initializations of a local function
>and eth_mac_addr for its ndo_set_mac_address field.  This change uses only
>the local function.
>
>The semantic match that finds this problem is as follows:
>(http://coccinelle.lip6.fr/)
>
>// <smpl>
>@r@
>identifier I, s, fld;
>position p0,p;
>expression E;
>@@
>
>struct I s =@p0 { ... .fld@p = E, ...};
>
>@s@
>identifier I, s, r.fld;
>position r.p0,p;
>expression E;
>@@
>
>struct I s =@p0 { ... .fld@p = E, ...};
>
>@script:python@
>p0 << r.p0;
>fld << r.fld;
>ps << s.p;
>pr << r.p;
>@@
>
>if int(ps[0].line)!=int(pr[0].line) or int(ps[0].column)!=int(pr[0].column):
>  cocci.print_main(fld,p0)
>// </smpl>


Hmm, C99 said:
"
The initialization shall occur in initializer list order, each
initializer provided for a particular subobject overriding any
previously listed initializer for the same subobject [...]
"

I am wondering why gcc doesn't (can't?) complain about this?

>
>Signed-off-by: Julia Lawall <julia@diku.dk>
>

Acked-by: WANG Cong <xiyou.wangcong@gmail.com>

>---
> arch/um/drivers/net_kern.c          |    1 -
> 1 files changed, 0 insertions(+), 1 deletions(-)
>
>diff --git a/arch/um/drivers/net_kern.c b/arch/um/drivers/net_kern.c
>index a74245a..d17a623 100644
>--- a/arch/um/drivers/net_kern.c
>+++ b/arch/um/drivers/net_kern.c
>@@ -379,7 +379,6 @@ static const struct net_device_ops uml_netdev_ops = {
> 	.ndo_tx_timeout 	= uml_net_tx_timeout,
> 	.ndo_set_mac_address	= uml_net_set_mac,
> 	.ndo_change_mtu 	= uml_net_change_mtu,
>-	.ndo_set_mac_address 	= eth_mac_addr,
> 	.ndo_validate_addr	= eth_validate_addr,
> };
> 
>--
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-- 
Live like a child, think like the god.
 

Re: [PATCH 5/5] arch/um: remove duplicate structure field initialization

[Segher Boessenkool]

> "
> The initialization shall occur in initializer list order, each
> initializer provided for a particular subobject overriding any
> previously listed initializer for the same subobject [...]
> "
>
> I am wondering why gcc doesn't (can't?) complain about this?

Does -Woverride-init (included in -Wextra / -W) not work?  If so, please
file a bug report.

Thanks,


Segher

Re: [PATCH 5/5] arch/um: remove duplicate structure field initialization

[Américo Wang]

On Tue, Sep 22, 2009 at 12:26 AM, Segher Boessenkool
<segher@kernel.crashing.org> wrote:
>> "
>> The initialization shall occur in initializer list order, each
>> initializer provided for a particular subobject overriding any
>> previously listed initializer for the same subobject [...]
>> "
>>
>> I am wondering why gcc doesn't (can't?) complain about this?
>
> Does -Woverride-init (included in -Wextra / -W) not work?  If so, please
> file a bug report.

Hmm, right, it works, but it seems that Linux kernel doesn't use it.
Maybe we should add it? :-/