subject:"\[RFC\] iommu\: arm\-smmu\: correct reference count"

Re: [RFC] iommu: arm-smmu: correct reference count

2015-11-08 Thread Peng Fan

Hi Will,

On Fri, Nov 06, 2015 at 12:23:39PM +, Will Deacon wrote:
>On Wed, Nov 04, 2015 at 10:48:28AM +0800, Peng Fan wrote:
>> On Tue, Nov 03, 2015 at 01:17:34PM +, Will Deacon wrote:
>> >On Tue, Nov 03, 2015 at 08:59:17PM +0800, Peng Fan wrote:
>> >> iommu_group_alloc will initialize the reference count for group to 1.
>> >> iommu_group_add_device also increase the group reference count,
>> >> if nothing bad happends. And we need to add iommu_group_put to
>> >> decrease the reference count for group.
>> >> 
>> >> Signed-off-by: Peng Fan 
>> >> Cc: Will Deacon 
>> >> Cc: Joerg Roedel 
>> >> ---
>> >> 
>> >> Not sure whether my understanding is correct or not. I checked 
>> >> rockchip-iommu.c
>> >> exynos-iommu.c and fsl_pamu_domain.c, and they all have iommu_group_put 
>> >> after
>> >> iommu_group_add_device.
>> >
>> >Doesn't this pair up with the iommu_group_remove_device in
>> >arm_smmu_remove_device? Are you actually seeing an issue in practice?
>> 
>> In arm_smmu_add_platform_device,
>> iommu_group_alloc --> group->device_kobj ref count will be init to 1.
>> iommu_group_add_device --> group->device_kobj ref count will be added 1 to 2.
>> 
>> In arm_smmu_remove_device:
>> iommu_group_remove_device --> Decrease group->device_kobj ref count by 1.
>> After arm_smmu_remove_device, the ref count of group->device_kobj is not 0.
>> 
>> So I think need to add iommu_group_put after iommu_group_add_device.
>> If I am wrong, please correct me.
>
>Ok, I see what you're saying. iommu_group_get_for_dev has exactly the
>same issue, so could you update arm-smmu-v3.c as well, please?

I did not see the update about device_group for iommu, when I worked out this 
patch.
Rebased to latest linux/master, whether to arm-smmu.c or arm-smmu-v3.c,
only add 'iommu_group_put' at the end of iommu_group_get_for_dev is ok as the
following.

I'll send out V2.

Thanks,
Peng.

>
>Thanks,
>
>Will
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [RFC] iommu: arm-smmu: correct reference count

2015-11-08 Thread Peng Fan

Hi Will,

On Fri, Nov 06, 2015 at 12:23:39PM +, Will Deacon wrote:
>On Wed, Nov 04, 2015 at 10:48:28AM +0800, Peng Fan wrote:
>> On Tue, Nov 03, 2015 at 01:17:34PM +, Will Deacon wrote:
>> >On Tue, Nov 03, 2015 at 08:59:17PM +0800, Peng Fan wrote:
>> >> iommu_group_alloc will initialize the reference count for group to 1.
>> >> iommu_group_add_device also increase the group reference count,
>> >> if nothing bad happends. And we need to add iommu_group_put to
>> >> decrease the reference count for group.
>> >> 
>> >> Signed-off-by: Peng Fan 
>> >> Cc: Will Deacon 
>> >> Cc: Joerg Roedel 
>> >> ---
>> >> 
>> >> Not sure whether my understanding is correct or not. I checked 
>> >> rockchip-iommu.c
>> >> exynos-iommu.c and fsl_pamu_domain.c, and they all have iommu_group_put 
>> >> after
>> >> iommu_group_add_device.
>> >
>> >Doesn't this pair up with the iommu_group_remove_device in
>> >arm_smmu_remove_device? Are you actually seeing an issue in practice?
>> 
>> In arm_smmu_add_platform_device,
>> iommu_group_alloc --> group->device_kobj ref count will be init to 1.
>> iommu_group_add_device --> group->device_kobj ref count will be added 1 to 2.
>> 
>> In arm_smmu_remove_device:
>> iommu_group_remove_device --> Decrease group->device_kobj ref count by 1.
>> After arm_smmu_remove_device, the ref count of group->device_kobj is not 0.
>> 
>> So I think need to add iommu_group_put after iommu_group_add_device.
>> If I am wrong, please correct me.
>
>Ok, I see what you're saying. iommu_group_get_for_dev has exactly the
>same issue, so could you update arm-smmu-v3.c as well, please?

I did not see the update about device_group for iommu, when I worked out this 
patch.
Rebased to latest linux/master, whether to arm-smmu.c or arm-smmu-v3.c,
only add 'iommu_group_put' at the end of iommu_group_get_for_dev is ok as the
following.

I'll send out V2.

Thanks,
Peng.

>
>Thanks,
>
>Will
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [RFC] iommu: arm-smmu: correct reference count

2015-11-06 Thread Will Deacon

On Wed, Nov 04, 2015 at 10:48:28AM +0800, Peng Fan wrote:
> On Tue, Nov 03, 2015 at 01:17:34PM +, Will Deacon wrote:
> >On Tue, Nov 03, 2015 at 08:59:17PM +0800, Peng Fan wrote:
> >> iommu_group_alloc will initialize the reference count for group to 1.
> >> iommu_group_add_device also increase the group reference count,
> >> if nothing bad happends. And we need to add iommu_group_put to
> >> decrease the reference count for group.
> >> 
> >> Signed-off-by: Peng Fan 
> >> Cc: Will Deacon 
> >> Cc: Joerg Roedel 
> >> ---
> >> 
> >> Not sure whether my understanding is correct or not. I checked 
> >> rockchip-iommu.c
> >> exynos-iommu.c and fsl_pamu_domain.c, and they all have iommu_group_put 
> >> after
> >> iommu_group_add_device.
> >
> >Doesn't this pair up with the iommu_group_remove_device in
> >arm_smmu_remove_device? Are you actually seeing an issue in practice?
> 
> In arm_smmu_add_platform_device,
> iommu_group_alloc --> group->device_kobj ref count will be init to 1.
> iommu_group_add_device --> group->device_kobj ref count will be added 1 to 2.
> 
> In arm_smmu_remove_device:
> iommu_group_remove_device --> Decrease group->device_kobj ref count by 1.
> After arm_smmu_remove_device, the ref count of group->device_kobj is not 0.
> 
> So I think need to add iommu_group_put after iommu_group_add_device.
> If I am wrong, please correct me.

Ok, I see what you're saying. iommu_group_get_for_dev has exactly the
same issue, so could you update arm-smmu-v3.c as well, please?

Thanks,

Will
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [RFC] iommu: arm-smmu: correct reference count

2015-11-06 Thread Will Deacon

On Wed, Nov 04, 2015 at 10:48:28AM +0800, Peng Fan wrote:
> On Tue, Nov 03, 2015 at 01:17:34PM +, Will Deacon wrote:
> >On Tue, Nov 03, 2015 at 08:59:17PM +0800, Peng Fan wrote:
> >> iommu_group_alloc will initialize the reference count for group to 1.
> >> iommu_group_add_device also increase the group reference count,
> >> if nothing bad happends. And we need to add iommu_group_put to
> >> decrease the reference count for group.
> >> 
> >> Signed-off-by: Peng Fan 
> >> Cc: Will Deacon 
> >> Cc: Joerg Roedel 
> >> ---
> >> 
> >> Not sure whether my understanding is correct or not. I checked 
> >> rockchip-iommu.c
> >> exynos-iommu.c and fsl_pamu_domain.c, and they all have iommu_group_put 
> >> after
> >> iommu_group_add_device.
> >
> >Doesn't this pair up with the iommu_group_remove_device in
> >arm_smmu_remove_device? Are you actually seeing an issue in practice?
> 
> In arm_smmu_add_platform_device,
> iommu_group_alloc --> group->device_kobj ref count will be init to 1.
> iommu_group_add_device --> group->device_kobj ref count will be added 1 to 2.
> 
> In arm_smmu_remove_device:
> iommu_group_remove_device --> Decrease group->device_kobj ref count by 1.
> After arm_smmu_remove_device, the ref count of group->device_kobj is not 0.
> 
> So I think need to add iommu_group_put after iommu_group_add_device.
> If I am wrong, please correct me.

Ok, I see what you're saying. iommu_group_get_for_dev has exactly the
same issue, so could you update arm-smmu-v3.c as well, please?

Thanks,

Will
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [RFC] iommu: arm-smmu: correct reference count

2015-11-03 Thread Peng Fan

Hi Will,

On Tue, Nov 03, 2015 at 01:17:34PM +, Will Deacon wrote:
>On Tue, Nov 03, 2015 at 08:59:17PM +0800, Peng Fan wrote:
>> iommu_group_alloc will initialize the reference count for group to 1.
>> iommu_group_add_device also increase the group reference count,
>> if nothing bad happends. And we need to add iommu_group_put to
>> decrease the reference count for group.
>> 
>> Signed-off-by: Peng Fan 
>> Cc: Will Deacon 
>> Cc: Joerg Roedel 
>> ---
>> 
>> Not sure whether my understanding is correct or not. I checked 
>> rockchip-iommu.c
>> exynos-iommu.c and fsl_pamu_domain.c, and they all have iommu_group_put after
>> iommu_group_add_device.
>
>Doesn't this pair up with the iommu_group_remove_device in
>arm_smmu_remove_device? Are you actually seeing an issue in practice?

In arm_smmu_add_platform_device,
iommu_group_alloc --> group->device_kobj ref count will be init to 1.
iommu_group_add_device --> group->device_kobj ref count will be added 1 to 2.

In arm_smmu_remove_device:
iommu_group_remove_device --> Decrease group->device_kobj ref count by 1.
After arm_smmu_remove_device, the ref count of group->device_kobj is not 0.

So I think need to add iommu_group_put after iommu_group_add_device.
If I am wrong, please correct me.

Just code inspection, not have a platform to test this.

Regards,
Peng.

>
>Will
>___
>iommu mailing list
>io...@lists.linux-foundation.org
>https://lists.linuxfoundation.org/mailman/listinfo/iommu

-- 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [RFC] iommu: arm-smmu: correct reference count

2015-11-03 Thread Will Deacon

On Tue, Nov 03, 2015 at 08:59:17PM +0800, Peng Fan wrote:
> iommu_group_alloc will initialize the reference count for group to 1.
> iommu_group_add_device also increase the group reference count,
> if nothing bad happends. And we need to add iommu_group_put to
> decrease the reference count for group.
> 
> Signed-off-by: Peng Fan 
> Cc: Will Deacon 
> Cc: Joerg Roedel 
> ---
> 
> Not sure whether my understanding is correct or not. I checked 
> rockchip-iommu.c
> exynos-iommu.c and fsl_pamu_domain.c, and they all have iommu_group_put after
> iommu_group_add_device.

Doesn't this pair up with the iommu_group_remove_device in
arm_smmu_remove_device? Are you actually seeing an issue in practice?

Will
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[RFC] iommu: arm-smmu: correct reference count

2015-11-03 Thread Peng Fan

iommu_group_alloc will initialize the reference count for group to 1.
iommu_group_add_device also increase the group reference count,
if nothing bad happends. And we need to add iommu_group_put to
decrease the reference count for group.

Signed-off-by: Peng Fan 
Cc: Will Deacon 
Cc: Joerg Roedel 
---

Not sure whether my understanding is correct or not. I checked rockchip-iommu.c
exynos-iommu.c and fsl_pamu_domain.c, and they all have iommu_group_put after
iommu_group_add_device.

 drivers/iommu/arm-smmu.c | 7 ++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 48a39df..1cab720 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -1344,6 +1344,7 @@ static int arm_smmu_add_platform_device(struct device 
*dev)
struct iommu_group *group;
struct arm_smmu_master *master;
struct arm_smmu_device *smmu = find_smmu_for_device(dev);
+   int ret;
 
if (!smmu)
return -ENODEV;
@@ -1358,7 +1359,11 @@ static int arm_smmu_add_platform_device(struct device 
*dev)
return PTR_ERR(group);
 
iommu_group_set_iommudata(group, >cfg, NULL);
-   return iommu_group_add_device(group, dev);
+
+   ret = iommu_group_add_device(group, dev);
+   iommu_group_put(group);
+
+   return ret;
 }
 
 static int arm_smmu_add_device(struct device *dev)
-- 
1.8.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[RFC] iommu: arm-smmu: correct reference count

2015-11-03 Thread Peng Fan

iommu_group_alloc will initialize the reference count for group to 1.
iommu_group_add_device also increase the group reference count,
if nothing bad happends. And we need to add iommu_group_put to
decrease the reference count for group.

Signed-off-by: Peng Fan 
Cc: Will Deacon 
Cc: Joerg Roedel 
---

Not sure whether my understanding is correct or not. I checked rockchip-iommu.c
exynos-iommu.c and fsl_pamu_domain.c, and they all have iommu_group_put after
iommu_group_add_device.

 drivers/iommu/arm-smmu.c | 7 ++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 48a39df..1cab720 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -1344,6 +1344,7 @@ static int arm_smmu_add_platform_device(struct device 
*dev)
struct iommu_group *group;
struct arm_smmu_master *master;
struct arm_smmu_device *smmu = find_smmu_for_device(dev);
+   int ret;
 
if (!smmu)
return -ENODEV;
@@ -1358,7 +1359,11 @@ static int arm_smmu_add_platform_device(struct device 
*dev)
return PTR_ERR(group);
 
iommu_group_set_iommudata(group, >cfg, NULL);
-   return iommu_group_add_device(group, dev);
+
+   ret = iommu_group_add_device(group, dev);
+   iommu_group_put(group);
+
+   return ret;
 }
 
 static int arm_smmu_add_device(struct device *dev)
-- 
1.8.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [RFC] iommu: arm-smmu: correct reference count

2015-11-03 Thread Will Deacon

On Tue, Nov 03, 2015 at 08:59:17PM +0800, Peng Fan wrote:
> iommu_group_alloc will initialize the reference count for group to 1.
> iommu_group_add_device also increase the group reference count,
> if nothing bad happends. And we need to add iommu_group_put to
> decrease the reference count for group.
> 
> Signed-off-by: Peng Fan 
> Cc: Will Deacon 
> Cc: Joerg Roedel 
> ---
> 
> Not sure whether my understanding is correct or not. I checked 
> rockchip-iommu.c
> exynos-iommu.c and fsl_pamu_domain.c, and they all have iommu_group_put after
> iommu_group_add_device.

Doesn't this pair up with the iommu_group_remove_device in
arm_smmu_remove_device? Are you actually seeing an issue in practice?

Will
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [RFC] iommu: arm-smmu: correct reference count

2015-11-03 Thread Peng Fan

Hi Will,

On Tue, Nov 03, 2015 at 01:17:34PM +, Will Deacon wrote:
>On Tue, Nov 03, 2015 at 08:59:17PM +0800, Peng Fan wrote:
>> iommu_group_alloc will initialize the reference count for group to 1.
>> iommu_group_add_device also increase the group reference count,
>> if nothing bad happends. And we need to add iommu_group_put to
>> decrease the reference count for group.
>> 
>> Signed-off-by: Peng Fan 
>> Cc: Will Deacon 
>> Cc: Joerg Roedel 
>> ---
>> 
>> Not sure whether my understanding is correct or not. I checked 
>> rockchip-iommu.c
>> exynos-iommu.c and fsl_pamu_domain.c, and they all have iommu_group_put after
>> iommu_group_add_device.
>
>Doesn't this pair up with the iommu_group_remove_device in
>arm_smmu_remove_device? Are you actually seeing an issue in practice?

In arm_smmu_add_platform_device,
iommu_group_alloc --> group->device_kobj ref count will be init to 1.
iommu_group_add_device --> group->device_kobj ref count will be added 1 to 2.

In arm_smmu_remove_device:
iommu_group_remove_device --> Decrease group->device_kobj ref count by 1.
After arm_smmu_remove_device, the ref count of group->device_kobj is not 0.

So I think need to add iommu_group_put after iommu_group_add_device.
If I am wrong, please correct me.

Just code inspection, not have a platform to test this.

Regards,
Peng.

>
>Will
>___
>iommu mailing list
>io...@lists.linux-foundation.org
>https://lists.linuxfoundation.org/mailman/listinfo/iommu

-- 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Re: [RFC] iommu: arm-smmu: correct reference count

Re: [RFC] iommu: arm-smmu: correct reference count

Re: [RFC] iommu: arm-smmu: correct reference count

Re: [RFC] iommu: arm-smmu: correct reference count

Re: [RFC] iommu: arm-smmu: correct reference count

Re: [RFC] iommu: arm-smmu: correct reference count

[RFC] iommu: arm-smmu: correct reference count

[RFC] iommu: arm-smmu: correct reference count

Re: [RFC] iommu: arm-smmu: correct reference count

Re: [RFC] iommu: arm-smmu: correct reference count

10 matches

Site Navigation

Mail list logo

Footer information