linux-kernel - Re: [PATCH] iommu: replace single-char identifiers in macros

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:   Mon, 3 Jun 2019 14:48:01 +0100
From:   Robin Murphy <robin.murphy@....com>
To:     Qian Cai <cai@....pw>, jroedel@...e.de
Cc:     akpm@...ux-foundation.org, iommu@...ts.linux-foundation.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] iommu: replace single-char identifiers in macros

On 03/06/2019 14:29, Qian Cai wrote:
> On Mon, 2019-06-03 at 14:07 +0100, Robin Murphy wrote:
>> On 03/06/2019 13:59, Qian Cai wrote:
>>> There are a few macros in IOMMU have single-char identifiers make the
>>> code hard to read and debug. Replace them with meaningful names.
>>>
>>> Suggested-by: Andrew Morton <akpm@...ux-foundation.org>
>>> Signed-off-by: Qian Cai <cai@....pw>
>>> ---
>>>    include/linux/dmar.h | 14 ++++++++------
>>>    1 file changed, 8 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/include/linux/dmar.h b/include/linux/dmar.h
>>> index f8af1d770520..eb634912f475 100644
>>> --- a/include/linux/dmar.h
>>> +++ b/include/linux/dmar.h
>>> @@ -104,12 +104,14 @@ static inline bool dmar_rcu_check(void)
>>>    
>>>    #define	dmar_rcu_dereference(p)	rcu_dereference_check((p),
>>> dmar_rcu_check())
>>>    
>>> -#define	for_each_dev_scope(a, c, p, d)	\
>>> -	for ((p) = 0; ((d) = (p) < (c) ? dmar_rcu_dereference((a)[(p)].dev)
>>> : \
>>> -			NULL, (p) < (c)); (p)++)
>>> -
>>> -#define	for_each_active_dev_scope(a, c, p, d)	\
>>> -	for_each_dev_scope((a), (c), (p), (d))	if (!(d)) { continue;
>>> } else
>>> +#define for_each_dev_scope(devs, cnt, i, tmp)				
>>> \
>>> +	for ((i) = 0; ((tmp) = (i) < (cnt) ?				
>>> \
>>
>> Given that "tmp" actually appears to be some sort of device cursor, I'm
>> not sure that that naming really achieves the stated goal of clarity :/
> 
> "tmp" is used in the callers everywhere though, although I suppose something
> like "tmp_dev" can be used if you prefer.

I don't have any preference, I'm just questioning the assertion in the 
commit message - as a reader not intimately familiar with this code, 
"tmp" is honestly no more meaningful than "d" was.

Robin.