mbox series

[net-next,0/8] Use max/min to simplify the code

Message ID 20240824074033.2134514-1-lihongbo22@huawei.com (mailing list archive)
Headers show
Series Use max/min to simplify the code | expand

Message

Hongbo Li Aug. 24, 2024, 7:40 a.m. UTC
Many Coccinelle/coccicheck warning reported by minmax.cocci
in net module, such as:
        WARNING opportunity for max()
        WARNING opportunity for min()

Let's use max/min to simplify the code and fix these warnings.
These patch have passed compilation test.

Hongbo Li (8):
  net/mac80211: use max to simplify the code
  net/rds: Use max() to simplify the code
  net/ipv4: Use min() to simplify the code
  net/core: Use min()/max() to simplify the code
  net/dccp: Use min()/max() to simplify the code
  net/openvswitch: Use max() to simplify the code
  net/rxrpc: Use min() to simplify the code
  net/ceph: Use min() to simplify the code

 net/ceph/osd_client.c     | 2 +-
 net/core/pktgen.c         | 6 ++----
 net/core/sock.c           | 2 +-
 net/dccp/ackvec.c         | 2 +-
 net/dccp/dccp.h           | 2 +-
 net/ipv4/ip_sockglue.c    | 2 +-
 net/mac80211/driver-ops.h | 2 +-
 net/mac80211/mlme.c       | 2 +-
 net/mac80211/scan.c       | 6 ++----
 net/mac80211/tdls.c       | 2 +-
 net/openvswitch/vport.c   | 2 +-
 net/rds/info.c            | 5 +----
 net/rxrpc/input.c         | 3 +--
 13 files changed, 15 insertions(+), 23 deletions(-)

Comments

Jakub Kicinski Aug. 26, 2024, 9:44 p.m. UTC | #1
On Sat, 24 Aug 2024 15:40:25 +0800 Hongbo Li wrote:
> Many Coccinelle/coccicheck warning reported by minmax.cocci
> in net module, such as:
>         WARNING opportunity for max()
>         WARNING opportunity for min()
> 
> Let's use max/min to simplify the code and fix these warnings.
> These patch have passed compilation test.

This set does not build.
Hongbo Li Aug. 27, 2024, 2:57 a.m. UTC | #2
On 2024/8/27 5:44, Jakub Kicinski wrote:
> On Sat, 24 Aug 2024 15:40:25 +0800 Hongbo Li wrote:
>> Many Coccinelle/coccicheck warning reported by minmax.cocci
>> in net module, such as:
>>          WARNING opportunity for max()
>>          WARNING opportunity for min()
>>
>> Let's use max/min to simplify the code and fix these warnings.
>> These patch have passed compilation test.
> 
> This set does not build.
> 
Do you mean some patches will go to other branches (such as mac80211)?

Thanks,
Hongbo
>
Kalle Valo Aug. 27, 2024, 4:45 a.m. UTC | #3
Hongbo Li <lihongbo22@huawei.com> writes:

> On 2024/8/27 5:44, Jakub Kicinski wrote:
>> On Sat, 24 Aug 2024 15:40:25 +0800 Hongbo Li wrote:
>>> Many Coccinelle/coccicheck warning reported by minmax.cocci
>>> in net module, such as:
>>>          WARNING opportunity for max()
>>>          WARNING opportunity for min()
>>>
>>> Let's use max/min to simplify the code and fix these warnings.
>>> These patch have passed compilation test.
>> This set does not build.
>> 
> Do you mean some patches will go to other branches (such as mac80211)?

Jakub means that your patchset had compilation errors, see the red on
patchwork:

https://patchwork.kernel.org/project/netdevbpf/list/?series=882901&state=*&order=date
Jakub Kicinski Aug. 27, 2024, 2:03 p.m. UTC | #4
On Tue, 27 Aug 2024 07:45:02 +0300 Kalle Valo wrote:
> > Do you mean some patches will go to other branches (such as mac80211)?  
> 
> Jakub means that your patchset had compilation errors, see the red on
> patchwork:
> 
> https://patchwork.kernel.org/project/netdevbpf/list/?series=882901&state=*&order=date

FWIW I prefer not to point noobs to the patchwork checks, lest they
think it's a public CI and they can fling broken code at the list :(
But yes, in case "code doesn't build" needs a further explanation:

net/core/pktgen.c: In function ‘pktgen_finalize_skb’:
./../include/linux/compiler_types.h:510:45: error: call to ‘__compiletime_assert_928’ declared with attribute error: min(datalen/frags, ((1UL) << 12)) signedness error
  510 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
      |                                             ^
./../include/linux/compiler_types.h:491:25: note: in definition of macro ‘__compiletime_assert’
  491 |                         prefix ## suffix();                             \
      |                         ^~~~~~
./../include/linux/compiler_types.h:510:9: note: in expansion of macro ‘_compiletime_assert’
  510 |         _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
      |         ^~~~~~~~~~~~~~~~~~~
../include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
   39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
      |                                     ^~~~~~~~~~~~~~~~~~
../include/linux/minmax.h:100:9: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
  100 |         BUILD_BUG_ON_MSG(!__types_ok(x,y,ux,uy),        \
      |         ^~~~~~~~~~~~~~~~
../include/linux/minmax.h:105:9: note: in expansion of macro ‘__careful_cmp_once’
  105 |         __careful_cmp_once(op, x, y, __UNIQUE_ID(x_), __UNIQUE_ID(y_))
      |         ^~~~~~~~~~~~~~~~~~
../include/linux/minmax.h:129:25: note: in expansion of macro ‘__careful_cmp’
  129 | #define min(x, y)       __careful_cmp(min, x, y)
      |                         ^~~~~~~~~~~~~
../net/core/pktgen.c:2796:28: note: in expansion of macro ‘min’
 2796 |                 frag_len = min(datalen/frags, PAGE_SIZE);
      |                            ^~~
make[5]: *** [../scripts/Makefile.build:244: net/core/pktgen.o] Error 1
Kalle Valo Aug. 27, 2024, 2:31 p.m. UTC | #5
Jakub Kicinski <kuba@kernel.org> writes:

> On Tue, 27 Aug 2024 07:45:02 +0300 Kalle Valo wrote:
>> > Do you mean some patches will go to other branches (such as mac80211)?  
>> 
>> Jakub means that your patchset had compilation errors, see the red on
>> patchwork:
>> 
>> https://patchwork.kernel.org/project/netdevbpf/list/?series=882901&state=*&order=date
>
> FWIW I prefer not to point noobs to the patchwork checks, lest they
> think it's a public CI and they can fling broken code at the list :(

Good point, that's definitely what we do not want. I'll keep this in
mind.
David Laight Aug. 30, 2024, 8:40 a.m. UTC | #6
From: Jakub Kicinski
> Sent: 27 August 2024 15:04
> 
> On Tue, 27 Aug 2024 07:45:02 +0300 Kalle Valo wrote:
> > > Do you mean some patches will go to other branches (such as mac80211)?
> >
> > Jakub means that your patchset had compilation errors, see the red on
> > patchwork:
> >
> > https://patchwork.kernel.org/project/netdevbpf/list/?series=882901&state=*&order=date
> 
> FWIW I prefer not to point noobs to the patchwork checks, lest they
> think it's a public CI and they can fling broken code at the list :(
> But yes, in case "code doesn't build" needs a further explanation:
> 
> net/core/pktgen.c: In function ‘pktgen_finalize_skb’:
> ./../include/linux/compiler_types.h:510:45: error: call to ‘__compiletime_assert_928’ declared with
> attribute error: min(datalen/frags, ((1UL) << 12)) signedness error
...
> ../net/core/pktgen.c:2796:28: note: in expansion of macro ‘min’
>  2796 |                 frag_len = min(datalen/frags, PAGE_SIZE);
>       |                            ^~~

I can't help feeling that a signed divide isn't intended here.
Which rather implies that both datalen and frags are signed types.
Whereas neither can be sensibly negative.
Perhaps that is the real bug?

	David

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