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From: Felix Fietkau <nbd@openwrt.org>
To: ath9k-devel@lists.ath9k.org
Subject: [ath9k-devel] [RFC] ath9k_hw: precedence bug in ath9k_hw_set_ofdm_nil()
Date: Tue, 10 Apr 2012 11:58:26 +0200	[thread overview]
Message-ID: <4F840442.5060706@openwrt.org> (raw)
In-Reply-To: <20120410090445.GB26832@elgon.mountain>

On 2012-04-10 11:04 AM, Dan Carpenter wrote:
> This was introduced in 54da20d83f "ath9k_hw: improve ANI processing and
> rx desensitizing parameters".  It triggers a Smatch complaint because
> the "if (!x != y) { ..." formation is a common precedence error.
> 
> In this case, maybe the code was intended to be as it is.  The
> "->ofdmWeakSigDetectOff" and "->ofdm_weak_signal_on" variables are both
> boolean.
> 
> Or perhaps based we could change the != to an == and remove the negate?
> 
> But normally when I see this formation it is a precedence bug so that's
> the patch I've sent.
> 
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> 
> diff --git a/drivers/net/wireless/ath/ath9k/ani.c b/drivers/net/wireless/ath/ath9k/ani.c
> index 47a9fb4..8304e27 100644
> --- a/drivers/net/wireless/ath/ath9k/ani.c
> +++ b/drivers/net/wireless/ath/ath9k/ani.c
> @@ -291,7 +291,7 @@ static void ath9k_hw_set_ofdm_nil(struct ath_hw *ah, u8 immunityLevel)
>  				     entry_ofdm->fir_step_level);
>  
>  	if ((aniState->noiseFloor >= aniState->rssiThrHigh) &&
> -	    (!aniState->ofdmWeakSigDetectOff !=
> +	    (aniState->ofdmWeakSigDetectOff !=
Looking at other Atheros code, I think this patch is wrong, it should
be: aniState->ofdmWeakSigDetectOff == entry_ofdm->ofdm_weak_signal_on

While a bit confusing, the behavior of the original code was correct,
aniState->ofdmWeakSigDetectOff is used as a boolean.

This code badly needs a cleanup, the whole mess with *on vs *off
variables is quite confusing.

- Felix

WARNING: multiple messages have this Message-ID (diff)
From: Felix Fietkau <nbd@openwrt.org>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Luis R. Rodriguez" <mcgrof@qca.qualcomm.com>,
	Rajkumar Manoharan <rmanohar@qca.qualcomm.com>,
	Vasanthakumar Thiagarajan <vthiagar@qca.qualcomm.com>,
	ath9k-devel@venema.h4ckr.net, kernel-janitors@vger.kernel.org,
	Jouni Malinen <jouni@qca.qualcomm.com>,
	linux-wireless@vger.kernel.org,
	"John W. Linville" <linville@tuxdriver.com>,
	Senthil Balasubramanian <senthilb@qca.qualcomm.com>
Subject: Re: [ath9k-devel] [RFC] ath9k_hw: precedence bug in ath9k_hw_set_ofdm_nil()
Date: Tue, 10 Apr 2012 09:58:26 +0000	[thread overview]
Message-ID: <4F840442.5060706@openwrt.org> (raw)
In-Reply-To: <20120410090445.GB26832@elgon.mountain>

On 2012-04-10 11:04 AM, Dan Carpenter wrote:
> This was introduced in 54da20d83f "ath9k_hw: improve ANI processing and
> rx desensitizing parameters".  It triggers a Smatch complaint because
> the "if (!x != y) { ..." formation is a common precedence error.
> 
> In this case, maybe the code was intended to be as it is.  The
> "->ofdmWeakSigDetectOff" and "->ofdm_weak_signal_on" variables are both
> boolean.
> 
> Or perhaps based we could change the != to an = and remove the negate?
> 
> But normally when I see this formation it is a precedence bug so that's
> the patch I've sent.
> 
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> 
> diff --git a/drivers/net/wireless/ath/ath9k/ani.c b/drivers/net/wireless/ath/ath9k/ani.c
> index 47a9fb4..8304e27 100644
> --- a/drivers/net/wireless/ath/ath9k/ani.c
> +++ b/drivers/net/wireless/ath/ath9k/ani.c
> @@ -291,7 +291,7 @@ static void ath9k_hw_set_ofdm_nil(struct ath_hw *ah, u8 immunityLevel)
>  				     entry_ofdm->fir_step_level);
>  
>  	if ((aniState->noiseFloor >= aniState->rssiThrHigh) &&
> -	    (!aniState->ofdmWeakSigDetectOff !> +	    (aniState->ofdmWeakSigDetectOff !Looking at other Atheros code, I think this patch is wrong, it should
be: aniState->ofdmWeakSigDetectOff = entry_ofdm->ofdm_weak_signal_on

While a bit confusing, the behavior of the original code was correct,
aniState->ofdmWeakSigDetectOff is used as a boolean.

This code badly needs a cleanup, the whole mess with *on vs *off
variables is quite confusing.

- Felix

WARNING: multiple messages have this Message-ID (diff)
From: Felix Fietkau <nbd@openwrt.org>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Luis R. Rodriguez" <mcgrof@qca.qualcomm.com>,
	Rajkumar Manoharan <rmanohar@qca.qualcomm.com>,
	Vasanthakumar Thiagarajan <vthiagar@qca.qualcomm.com>,
	ath9k-devel@venema.h4ckr.net, kernel-janitors@vger.kernel.org,
	Jouni Malinen <jouni@qca.qualcomm.com>,
	linux-wireless@vger.kernel.org,
	"John W. Linville" <linville@tuxdriver.com>,
	Senthil Balasubramanian <senthilb@qca.qualcomm.com>
Subject: Re: [ath9k-devel] [RFC] ath9k_hw: precedence bug in ath9k_hw_set_ofdm_nil()
Date: Tue, 10 Apr 2012 11:58:26 +0200	[thread overview]
Message-ID: <4F840442.5060706@openwrt.org> (raw)
In-Reply-To: <20120410090445.GB26832@elgon.mountain>

On 2012-04-10 11:04 AM, Dan Carpenter wrote:
> This was introduced in 54da20d83f "ath9k_hw: improve ANI processing and
> rx desensitizing parameters".  It triggers a Smatch complaint because
> the "if (!x != y) { ..." formation is a common precedence error.
> 
> In this case, maybe the code was intended to be as it is.  The
> "->ofdmWeakSigDetectOff" and "->ofdm_weak_signal_on" variables are both
> boolean.
> 
> Or perhaps based we could change the != to an == and remove the negate?
> 
> But normally when I see this formation it is a precedence bug so that's
> the patch I've sent.
> 
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> 
> diff --git a/drivers/net/wireless/ath/ath9k/ani.c b/drivers/net/wireless/ath/ath9k/ani.c
> index 47a9fb4..8304e27 100644
> --- a/drivers/net/wireless/ath/ath9k/ani.c
> +++ b/drivers/net/wireless/ath/ath9k/ani.c
> @@ -291,7 +291,7 @@ static void ath9k_hw_set_ofdm_nil(struct ath_hw *ah, u8 immunityLevel)
>  				     entry_ofdm->fir_step_level);
>  
>  	if ((aniState->noiseFloor >= aniState->rssiThrHigh) &&
> -	    (!aniState->ofdmWeakSigDetectOff !=
> +	    (aniState->ofdmWeakSigDetectOff !=
Looking at other Atheros code, I think this patch is wrong, it should
be: aniState->ofdmWeakSigDetectOff == entry_ofdm->ofdm_weak_signal_on

While a bit confusing, the behavior of the original code was correct,
aniState->ofdmWeakSigDetectOff is used as a boolean.

This code badly needs a cleanup, the whole mess with *on vs *off
variables is quite confusing.

- Felix

  reply	other threads:[~2012-04-10  9:58 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-10  9:04 [ath9k-devel] [RFC] ath9k_hw: precedence bug in ath9k_hw_set_ofdm_nil() Dan Carpenter
2012-04-10  9:04 ` Dan Carpenter
2012-04-10  9:04 ` Dan Carpenter
2012-04-10  9:58 ` Felix Fietkau [this message]
2012-04-10  9:58   ` [ath9k-devel] " Felix Fietkau
2012-04-10  9:58   ` Felix Fietkau
2012-04-10 10:57   ` Dan Carpenter
2012-04-10 10:57     ` Dan Carpenter
2012-04-10 10:57     ` Dan Carpenter
2012-04-10 12:50     ` Rajkumar Manoharan
2012-04-10 12:51       ` Rajkumar Manoharan
2012-04-10 12:50       ` Rajkumar Manoharan

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