linux-kernel - Re: [PATCH 3/3] iommu/arm-smmu: Error out only if not enough context interrupts

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Date:   Wed, 25 Jul 2018 12:57:30 +0100
From:   Will Deacon <will.deacon@....com>
To:     Vivek Gautam <vivek.gautam@...eaurora.org>
Cc:     joro@...tes.org, robh+dt@...nel.org, robin.murphy@....com,
        andy.gross@...aro.org, mark.rutland@....com,
        iommu@...ts.linux-foundation.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, tfiga@...omium.org,
        sricharan@...eaurora.org, linux-arm-msm@...r.kernel.org,
        david.brown@...aro.org, linux-soc@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 3/3] iommu/arm-smmu: Error out only if not enough context
 interrupts

On Tue, Jul 24, 2018 at 03:09:41PM +0530, Vivek Gautam wrote:
> On 7/24/2018 2:06 PM, Will Deacon wrote:
> >On Thu, Jul 19, 2018 at 11:23:56PM +0530, Vivek Gautam wrote:
> >>diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> >>index 7c69736a30f8..4cb53bf4f423 100644
> >>--- a/drivers/iommu/arm-smmu.c
> >>+++ b/drivers/iommu/arm-smmu.c
> >>@@ -2229,12 +2229,19 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
> >>  	if (err)
> >>  		return err;
> >>-	if (smmu->version == ARM_SMMU_V2 &&
> >>-	    smmu->num_context_banks != smmu->num_context_irqs) {
> >>-		dev_err(dev,
> >>-			"found only %d context interrupt(s) but %d required\n",
> >>-			smmu->num_context_irqs, smmu->num_context_banks);
> >>-		return -ENODEV;
> >>+	if (smmu->version == ARM_SMMU_V2) {
> >>+		if (smmu->num_context_banks > smmu->num_context_irqs) {
> >>+			dev_err(dev,
> >>+			      "found only %d context irq(s) but %d required\n",
> >>+			      smmu->num_context_irqs, smmu->num_context_banks);
> >>+			return -ENODEV;
> >>+		} else if (smmu->num_context_banks < smmu->num_context_irqs) {
> >>+			/* loose extra context interrupts */
> >>+			dev_notice(dev,
> >>+			      "found %d context irq(s) but only %d required\n",
> >>+			      smmu->num_context_irqs, smmu->num_context_banks);
> >>+			smmu->num_context_irqs = smmu->num_context_banks;
> >>+		}
> >I don't see the utility in the new message. Can you simplify with the patch
> >below on top? It's a bit weird that we only decide to ignore the extra irqs
> >after calling platform_get_irq() on them, but that seems to be harmless.
> 
> Thanks. I will modify as suggested below and respin.

It's ok, I can make the change locally.

Will