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From: Robin Murphy <robin.murphy@arm.com>
To: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Cc: jean-philippe@linaro.org, linux-kernel@vger.kernel.org,
	linuxarm@openeuler.org, iommu@lists.linux-foundation.org,
	prime.zeng@hisilicon.com, will@kernel.org
Subject: Re: [PATCH] iommu: Check dev->iommu in iommu_dev_xxx functions
Date: Tue, 26 Jan 2021 13:50:40 +0000	[thread overview]
Message-ID: <20210126135039.000039a0@arm.com> (raw)
In-Reply-To: <20210126130629.8928-1-shameerali.kolothum.thodi@huawei.com>

On Tue, 26 Jan 2021 13:06:29 +0000
Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> wrote:

> The device iommu probe/attach might have failed leaving dev->iommu
> to NULL and device drivers may still invoke these functions resulting
> a crash in iommu vendor driver code. Hence make sure we check that.
> 
> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> ---
>  drivers/iommu/iommu.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index ffeebda8d6de..cb68153c5cc0 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -2867,7 +2867,7 @@ bool iommu_dev_has_feature(struct device *dev,
> enum iommu_dev_features feat) {
>  	const struct iommu_ops *ops = dev->bus->iommu_ops;
>  
> -	if (ops && ops->dev_has_feat)
> +	if (dev->iommu && ops && ops->dev_has_feat)
>  		return ops->dev_has_feat(dev, feat);

Might make sense to make these more self-contained, e.g.:

	if (dev->iommu && dev->iommu->ops->foo)
		dev->iommu->ops->foo()

Robin.

 
>  	return false;
> @@ -2878,7 +2878,7 @@ int iommu_dev_enable_feature(struct device
> *dev, enum iommu_dev_features feat) {
>  	const struct iommu_ops *ops = dev->bus->iommu_ops;
>  
> -	if (ops && ops->dev_enable_feat)
> +	if (dev->iommu && ops && ops->dev_enable_feat)
>  		return ops->dev_enable_feat(dev, feat);
>  
>  	return -ENODEV;
> @@ -2894,7 +2894,7 @@ int iommu_dev_disable_feature(struct device
> *dev, enum iommu_dev_features feat) {
>  	const struct iommu_ops *ops = dev->bus->iommu_ops;
>  
> -	if (ops && ops->dev_disable_feat)
> +	if (dev->iommu && ops && ops->dev_disable_feat)
>  		return ops->dev_disable_feat(dev, feat);
>  
>  	return -EBUSY;
> @@ -2905,7 +2905,7 @@ bool iommu_dev_feature_enabled(struct device
> *dev, enum iommu_dev_features feat) {
>  	const struct iommu_ops *ops = dev->bus->iommu_ops;
>  
> -	if (ops && ops->dev_feat_enabled)
> +	if (dev->iommu && ops && ops->dev_feat_enabled)
>  		return ops->dev_feat_enabled(dev, feat);
>  
>  	return false;

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

WARNING: multiple messages have this Message-ID (diff)
From: Robin Murphy <robin.murphy@arm.com>
To: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Cc: <linux-kernel@vger.kernel.org>,
	<iommu@lists.linux-foundation.org>,
	jean-philippe@linaro.org, will@kernel.org,
	linuxarm@openeuler.org, prime.zeng@hisilicon.com
Subject: Re: [PATCH] iommu: Check dev->iommu in iommu_dev_xxx functions
Date: Tue, 26 Jan 2021 13:50:40 +0000	[thread overview]
Message-ID: <20210126135039.000039a0@arm.com> (raw)
In-Reply-To: <20210126130629.8928-1-shameerali.kolothum.thodi@huawei.com>

On Tue, 26 Jan 2021 13:06:29 +0000
Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> wrote:

> The device iommu probe/attach might have failed leaving dev->iommu
> to NULL and device drivers may still invoke these functions resulting
> a crash in iommu vendor driver code. Hence make sure we check that.
> 
> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> ---
>  drivers/iommu/iommu.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index ffeebda8d6de..cb68153c5cc0 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -2867,7 +2867,7 @@ bool iommu_dev_has_feature(struct device *dev,
> enum iommu_dev_features feat) {
>  	const struct iommu_ops *ops = dev->bus->iommu_ops;
>  
> -	if (ops && ops->dev_has_feat)
> +	if (dev->iommu && ops && ops->dev_has_feat)
>  		return ops->dev_has_feat(dev, feat);

Might make sense to make these more self-contained, e.g.:

	if (dev->iommu && dev->iommu->ops->foo)
		dev->iommu->ops->foo()

Robin.

 
>  	return false;
> @@ -2878,7 +2878,7 @@ int iommu_dev_enable_feature(struct device
> *dev, enum iommu_dev_features feat) {
>  	const struct iommu_ops *ops = dev->bus->iommu_ops;
>  
> -	if (ops && ops->dev_enable_feat)
> +	if (dev->iommu && ops && ops->dev_enable_feat)
>  		return ops->dev_enable_feat(dev, feat);
>  
>  	return -ENODEV;
> @@ -2894,7 +2894,7 @@ int iommu_dev_disable_feature(struct device
> *dev, enum iommu_dev_features feat) {
>  	const struct iommu_ops *ops = dev->bus->iommu_ops;
>  
> -	if (ops && ops->dev_disable_feat)
> +	if (dev->iommu && ops && ops->dev_disable_feat)
>  		return ops->dev_disable_feat(dev, feat);
>  
>  	return -EBUSY;
> @@ -2905,7 +2905,7 @@ bool iommu_dev_feature_enabled(struct device
> *dev, enum iommu_dev_features feat) {
>  	const struct iommu_ops *ops = dev->bus->iommu_ops;
>  
> -	if (ops && ops->dev_feat_enabled)
> +	if (dev->iommu && ops && ops->dev_feat_enabled)
>  		return ops->dev_feat_enabled(dev, feat);
>  
>  	return false;


  reply	other threads:[~2021-01-26 13:51 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-26 13:06 [PATCH] iommu: Check dev->iommu in iommu_dev_xxx functions Shameer Kolothum
2021-01-26 13:06 ` Shameer Kolothum
2021-01-26 13:50 ` Robin Murphy [this message]
2021-01-26 13:50   ` Robin Murphy
2021-01-26 16:40   ` Shameerali Kolothum Thodi
2021-01-26 16:40     ` Shameerali Kolothum Thodi
2021-01-26 17:24     ` Robin Murphy
2021-01-26 17:24       ` Robin Murphy
2021-01-28 12:54 ` Joerg Roedel
2021-01-28 12:54   ` Joerg Roedel

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