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From: Sergey Shtylyov <s.shtylyov@auroraos.dev>
To: Sean Young <sean@mess.org>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>,
	<linux-media@vger.kernel.org>
Subject: Re: [PATCH] media: rc: rc-ir-raw: drop useless decrements in ir_raw_gen_{manchester,pl}()
Date: Wed, 19 Aug 2026 18:17:22 +0300	[thread overview]
Message-ID: <70b2ba72-649d-4ef0-b5f1-367eb47f6f12@auroraos.dev> (raw)
In-Reply-To: <aoVbzp0cn1euNa_h@extorris.mess.org>

On 8/19/26 10:31 AM, Sean Young wrote:
[...]

>> In ir_raw_gen_{manchester,pl}(), the paremeter max is usually decremented
>> while checking it for 0 but sometimes that action seems fruitless as max
>> isn't used afterwards -- drop the useless decrement operators...
>>
>> Found by Linux Verification Center (linuxtesting.org) with the Svace static
>> analysis tool.
>>
>> Signed-off-by: Sergey Shtylyov <s.shtylyov@auroraos.dev>
>> ---
>> The patch is against the next branch of the linuxtv.org/media.git repo...
>>
>>  drivers/media/rc/rc-ir-raw.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/media/rc/rc-ir-raw.c b/drivers/media/rc/rc-ir-raw.c
>> index ba24c2f22d39..ed494be8896f 100644
>> --- a/drivers/media/rc/rc-ir-raw.c
>> +++ b/drivers/media/rc/rc-ir-raw.c
>> @@ -362,7 +362,7 @@ int ir_raw_gen_manchester(struct ir_raw_event **ev, unsigned int max,
>>       if (timings->trailer_space) {
>>               if (!(*ev)->pulse)
>>                       (*ev)->duration += timings->trailer_space;
>> -             else if (!max--)
>> +             else if (!max)
>>                       goto nobufs;
>>               else
>>                       init_ir_raw_event_duration(++(*ev), 0,
>> @@ -491,7 +491,7 @@ int ir_raw_gen_pl(struct ir_raw_event **ev, unsigned int max,
>>               }
>>       }
>>
>> -     if (!max--)
>> +     if (!max)
> 
> This patch is technically correct, but won't make any difference to
> generated code. The decremented value of max will have zero users in the

   After looking at the .lst file (that wasn't easy), you're correct...

> SSA tree, and will be droppped.

    Had to google SSA tree... :-)

> Changing this is purely cosmetic change to the code.

   Makes the code a bit clearer, no? 
> Sean
[...]

MBR, Sergey


      reply	other threads:[~2026-08-19 15:17 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-18 20:38 [PATCH] media: rc: rc-ir-raw: drop useless decrements in ir_raw_gen_{manchester,pl}() Sergey Shtylyov
2026-08-18 20:54 ` Sergey Shtylyov
2026-08-19  7:31 ` Sean Young
2026-08-19 15:17   ` Sergey Shtylyov [this message]

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