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From: Bjorn Helgaas <helgaas@kernel.org>
To: "Krzysztof Wilczyński" <kw@linux.com>
Cc: Toan Le <toan@os.amperecomputing.com>,
	Rob Herring <robh@kernel.org>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	linux-pci@vger.kernel.org, Duc Dang <dhdang@apm.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] PCI: xgene: Remove unused assignment to variable msi_val
Date: Tue, 22 Sep 2020 09:52:45 -0500	[thread overview]
Message-ID: <20200922145245.GA2201556@bjorn-Precision-5520> (raw)
In-Reply-To: <20200922030257.459898-1-kw@linux.com>

On Tue, Sep 22, 2020 at 03:02:57AM +0000, Krzysztof Wilczyński wrote:
> The value assigned to msi_val after the inner loop finishes its run is
> never used for anything, and it is also immediately overridden in the
> line that follows with the return value from the xgene_msi_int_read()
> function.
> 
> Since the value of msi_val following the inner loop completion is never
> used in any meaningful way the assignment can be removed.
> 
> Addresses-Coverity-ID: 1437183 ("Unused value")
> Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
> ---
>  drivers/pci/controller/pci-xgene-msi.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/controller/pci-xgene-msi.c b/drivers/pci/controller/pci-xgene-msi.c
> index 02271c6d17a1..2470782cb01a 100644
> --- a/drivers/pci/controller/pci-xgene-msi.c
> +++ b/drivers/pci/controller/pci-xgene-msi.c
> @@ -493,8 +493,8 @@ static int xgene_msi_probe(struct platform_device *pdev)
>  	 */
>  	for (irq_index = 0; irq_index < NR_HW_IRQS; irq_index++) {
>  		for (msi_idx = 0; msi_idx < IDX_PER_GROUP; msi_idx++)
> -			msi_val = xgene_msi_ir_read(xgene_msi, irq_index,
> -						    msi_idx);
> +			xgene_msi_ir_read(xgene_msi, irq_index, msi_idx);
> +

Interesting.  One might expect that throwing away the result of a read
means the read itself is pointless, but fortunately there's a comment
just above explaining that these registers are read-to-clear.

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

Assuming Toan acks this, Lorenzo will likely pick it up when he
returns next week.

>  		/* Read MSIINTn to confirm */
>  		msi_val = xgene_msi_int_read(xgene_msi, irq_index);
>  		if (msi_val) {
> -- 
> 2.28.0
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

WARNING: multiple messages have this Message-ID (diff)
From: Bjorn Helgaas <helgaas@kernel.org>
To: "Krzysztof Wilczyński" <kw@linux.com>
Cc: Rob Herring <robh@kernel.org>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	linux-pci@vger.kernel.org, Duc Dang <dhdang@apm.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Toan Le <toan@os.amperecomputing.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] PCI: xgene: Remove unused assignment to variable msi_val
Date: Tue, 22 Sep 2020 09:52:45 -0500	[thread overview]
Message-ID: <20200922145245.GA2201556@bjorn-Precision-5520> (raw)
In-Reply-To: <20200922030257.459898-1-kw@linux.com>

On Tue, Sep 22, 2020 at 03:02:57AM +0000, Krzysztof Wilczyński wrote:
> The value assigned to msi_val after the inner loop finishes its run is
> never used for anything, and it is also immediately overridden in the
> line that follows with the return value from the xgene_msi_int_read()
> function.
> 
> Since the value of msi_val following the inner loop completion is never
> used in any meaningful way the assignment can be removed.
> 
> Addresses-Coverity-ID: 1437183 ("Unused value")
> Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
> ---
>  drivers/pci/controller/pci-xgene-msi.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/controller/pci-xgene-msi.c b/drivers/pci/controller/pci-xgene-msi.c
> index 02271c6d17a1..2470782cb01a 100644
> --- a/drivers/pci/controller/pci-xgene-msi.c
> +++ b/drivers/pci/controller/pci-xgene-msi.c
> @@ -493,8 +493,8 @@ static int xgene_msi_probe(struct platform_device *pdev)
>  	 */
>  	for (irq_index = 0; irq_index < NR_HW_IRQS; irq_index++) {
>  		for (msi_idx = 0; msi_idx < IDX_PER_GROUP; msi_idx++)
> -			msi_val = xgene_msi_ir_read(xgene_msi, irq_index,
> -						    msi_idx);
> +			xgene_msi_ir_read(xgene_msi, irq_index, msi_idx);
> +

Interesting.  One might expect that throwing away the result of a read
means the read itself is pointless, but fortunately there's a comment
just above explaining that these registers are read-to-clear.

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

Assuming Toan acks this, Lorenzo will likely pick it up when he
returns next week.

>  		/* Read MSIINTn to confirm */
>  		msi_val = xgene_msi_int_read(xgene_msi, irq_index);
>  		if (msi_val) {
> -- 
> 2.28.0
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2020-09-22 14:52 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-22  3:02 [PATCH] PCI: xgene: Remove unused assignment to variable msi_val Krzysztof Wilczyński
2020-09-22  3:02 ` Krzysztof Wilczyński
2020-09-22 14:52 ` Bjorn Helgaas [this message]
2020-09-22 14:52   ` Bjorn Helgaas
2020-10-01 14:42 ` Rob Herring
2020-10-01 14:42   ` Rob Herring
2020-10-02 12:00 ` Lorenzo Pieralisi
2020-10-02 12:00   ` Lorenzo Pieralisi

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