From: Ivan Safonov <insafonov@gmail.com>
To: ath9k-devel@lists.ath9k.org
Subject: [ath9k-devel] [PATCH] /drivers/net/wireless/ath/ath9k remove unnecessary ?: operator
Date: Tue, 29 Dec 2015 01:38:02 +0700 [thread overview]
Message-ID: <5681818A.9060406@gmail.com> (raw)
In-Reply-To: <1451325412.3219.12.camel@perches.com>
On 12/29/2015 12:56 AM, Joe Perches wrote:
> On Mon, 2015-12-28 at 20:48 +0700, Ivan Safonov wrote:
>> ((thermometer < 0) ? 0 : (thermometer == X)) and (thermometer == X) are equal for X >= 0.
> X is not guaranteed to be >= 0 here
X is fixed constant. In this case X is {0, 1, 2}.
>> @@ -4097,16 +4097,16 @@ static void ar9003_hw_thermometer_apply(struct ath_hw *ah)
>> REG_RMW_FIELD(ah, AR_PHY_65NM_CH2_RXTX4,
>> AR_PHY_65NM_CH0_RXTX4_THERM_ON_OVR, therm_on);
>>
>> - therm_on = (thermometer < 0) ? 0 : (thermometer == 0);
>> + therm_on = thermometer == 0;
> This code is not equivalent.
>
> Check what happens when thermometer is -1.
therm_on = (thermometer < 0) ? 0 : (thermometer == 0) =>
therm_on = (true) ? 0 : (thermometer == 0) =>
therm_on is 0
therm_on = thermometer == 0 =>
therm_on = false
false is equal to 0
Value of the thermometer variable isanerror code, or athermometercode.
The thermometercode is never equal to the error code (thermometercode >=
0, error code <0).
WARNING: multiple messages have this Message-ID (diff)
From: Ivan Safonov <insafonov@gmail.com>
To: Joe Perches <joe@perches.com>,
QCA ath9k Development <ath9k-devel@qca.qualcomm.com>
Cc: Kalle Valo <kvalo@codeaurora.org>,
linux-wireless@vger.kernel.org, ath9k-devel@lists.ath9k.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] /drivers/net/wireless/ath/ath9k remove unnecessary ?: operator
Date: Tue, 29 Dec 2015 01:38:02 +0700 [thread overview]
Message-ID: <5681818A.9060406@gmail.com> (raw)
In-Reply-To: <1451325412.3219.12.camel@perches.com>
On 12/29/2015 12:56 AM, Joe Perches wrote:
> On Mon, 2015-12-28 at 20:48 +0700, Ivan Safonov wrote:
>> ((thermometer < 0) ? 0 : (thermometer == X)) and (thermometer == X) are equal for X >= 0.
> X is not guaranteed to be >= 0 here
X is fixed constant. In this case X is {0, 1, 2}.
>> @@ -4097,16 +4097,16 @@ static void ar9003_hw_thermometer_apply(struct ath_hw *ah)
>> REG_RMW_FIELD(ah, AR_PHY_65NM_CH2_RXTX4,
>> AR_PHY_65NM_CH0_RXTX4_THERM_ON_OVR, therm_on);
>>
>> - therm_on = (thermometer < 0) ? 0 : (thermometer == 0);
>> + therm_on = thermometer == 0;
> This code is not equivalent.
>
> Check what happens when thermometer is -1.
therm_on = (thermometer < 0) ? 0 : (thermometer == 0) =>
therm_on = (true) ? 0 : (thermometer == 0) =>
therm_on is 0
therm_on = thermometer == 0 =>
therm_on = false
false is equal to 0
Value of the thermometer variable isanerror code, or athermometercode.
The thermometercode is never equal to the error code (thermometercode >=
0, error code <0).
WARNING: multiple messages have this Message-ID (diff)
From: Ivan Safonov <insafonov@gmail.com>
To: Joe Perches <joe@perches.com>,
QCA ath9k Development <ath9k-devel@qca.qualcomm.com>
Cc: Kalle Valo <kvalo@codeaurora.org>,
linux-wireless@vger.kernel.org, ath9k-devel@venema.h4ckr.net,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] /drivers/net/wireless/ath/ath9k remove unnecessary ?: operator
Date: Tue, 29 Dec 2015 01:38:02 +0700 [thread overview]
Message-ID: <5681818A.9060406@gmail.com> (raw)
In-Reply-To: <1451325412.3219.12.camel@perches.com>
On 12/29/2015 12:56 AM, Joe Perches wrote:
> On Mon, 2015-12-28 at 20:48 +0700, Ivan Safonov wrote:
>> ((thermometer < 0) ? 0 : (thermometer == X)) and (thermometer == X) are equal for X >= 0.
> X is not guaranteed to be >= 0 here
X is fixed constant. In this case X is {0, 1, 2}.
>> @@ -4097,16 +4097,16 @@ static void ar9003_hw_thermometer_apply(struct ath_hw *ah)
>> REG_RMW_FIELD(ah, AR_PHY_65NM_CH2_RXTX4,
>> AR_PHY_65NM_CH0_RXTX4_THERM_ON_OVR, therm_on);
>>
>> - therm_on = (thermometer < 0) ? 0 : (thermometer == 0);
>> + therm_on = thermometer == 0;
> This code is not equivalent.
>
> Check what happens when thermometer is -1.
therm_on = (thermometer < 0) ? 0 : (thermometer == 0) =>
therm_on = (true) ? 0 : (thermometer == 0) =>
therm_on is 0
therm_on = thermometer == 0 =>
therm_on = false
false is equal to 0
Value of the thermometer variable isanerror code, or athermometercode.
The thermometercode is never equal to the error code (thermometercode >=
0, error code <0).
next prev parent reply other threads:[~2015-12-28 18:38 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-28 13:48 [ath9k-devel] [PATCH] /drivers/net/wireless/ath/ath9k remove unnecessary ?: operator Ivan Safonov
2015-12-28 13:48 ` Ivan Safonov
2015-12-28 13:48 ` Ivan Safonov
2015-12-28 17:56 ` [ath9k-devel] " Joe Perches
2015-12-28 17:56 ` Joe Perches
2015-12-28 17:56 ` Joe Perches
2015-12-28 17:56 ` Joe Perches
2015-12-28 18:38 ` Ivan Safonov [this message]
2015-12-28 18:38 ` Ivan Safonov
2015-12-28 18:38 ` Ivan Safonov
2015-12-29 0:31 ` [ath9k-devel] " Joe Perches
2015-12-29 0:31 ` Joe Perches
2015-12-29 0:31 ` Joe Perches
2015-12-29 4:11 ` [ath9k-devel] " Ivan Safonov
2015-12-29 4:11 ` Ivan Safonov
2015-12-29 4:11 ` Ivan Safonov
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