As IOMMU groups are exposed to the user space by their numbers,
the user space can use them in various kernel APIs so the kernel
might need an API to find a group by its ID.
As an example, QEMU VFIO on PPC64 platform needs it to associate
a logical bus number (LIOBN) with a specific IOMMU group in order
to support in-kernel handling of DMA map/unmap requests.
The patch adds the iommu_group_find(id) function which performs
such search.
Signed-off-by: Alexey Kardashevskiy <[email protected]>
---
drivers/iommu/iommu.c | 26 ++++++++++++++++++++++++++
include/linux/iommu.h | 1 +
2 files changed, 27 insertions(+)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index b0afd3d..6340cac 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -205,6 +205,32 @@ printk("%s %u grp %d\n", __func__, __LINE__, iommu_group_id(group));
}
EXPORT_SYMBOL_GPL(iommu_group_alloc);
+struct iommu_group *iommu_group_find(int id)
+{
+ struct kobject *group_kobj;
+ struct iommu_group *grp;
+ const char *name;
+
+ if (!iommu_group_kset)
+ return NULL;
+
+ name = kasprintf(GFP_KERNEL, "%d", id);
+ if (!name)
+ return NULL;
+
+ group_kobj = kset_find_obj(iommu_group_kset, name);
+ kfree(name);
+
+ if (!group_kobj)
+ return NULL;
+
+ grp = container_of(group_kobj, struct iommu_group, kobj);
+ BUG_ON(grp->id != id);
+
+ return grp;
+}
+EXPORT_SYMBOL_GPL(iommu_group_find);
+
/**
* iommu_group_get_iommudata - retrieve iommu_data registered for a group
* @group: the group
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index f3b99e1..20281d5 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -113,6 +113,7 @@ struct iommu_ops {
extern int bus_set_iommu(struct bus_type *bus, struct iommu_ops *ops);
extern bool iommu_present(struct bus_type *bus);
extern struct iommu_domain *iommu_domain_alloc(struct bus_type *bus);
+extern struct iommu_group *iommu_group_find(int id);
extern void iommu_domain_free(struct iommu_domain *domain);
extern int iommu_attach_device(struct iommu_domain *domain,
struct device *dev);
--
1.7.10.4
On Thu, 2013-03-21 at 18:48 +1100, Alexey Kardashevskiy wrote:
> As IOMMU groups are exposed to the user space by their numbers,
> the user space can use them in various kernel APIs so the kernel
> might need an API to find a group by its ID.
>
> As an example, QEMU VFIO on PPC64 platform needs it to associate
> a logical bus number (LIOBN) with a specific IOMMU group in order
> to support in-kernel handling of DMA map/unmap requests.
>
> The patch adds the iommu_group_find(id) function which performs
> such search.
>
> Signed-off-by: Alexey Kardashevskiy <[email protected]>
> ---
> drivers/iommu/iommu.c | 26 ++++++++++++++++++++++++++
> include/linux/iommu.h | 1 +
> 2 files changed, 27 insertions(+)
>
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index b0afd3d..6340cac 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -205,6 +205,32 @@ printk("%s %u grp %d\n", __func__, __LINE__, iommu_group_id(group));
> }
> EXPORT_SYMBOL_GPL(iommu_group_alloc);
>
> +struct iommu_group *iommu_group_find(int id)
> +{
> + struct kobject *group_kobj;
> + struct iommu_group *grp;
> + const char *name;
> +
> + if (!iommu_group_kset)
> + return NULL;
> +
> + name = kasprintf(GFP_KERNEL, "%d", id);
> + if (!name)
> + return NULL;
> +
> + group_kobj = kset_find_obj(iommu_group_kset, name);
> + kfree(name);
> +
> + if (!group_kobj)
> + return NULL;
> +
> + grp = container_of(group_kobj, struct iommu_group, kobj);
> + BUG_ON(grp->id != id);
> +
> + return grp;
> +}
> +EXPORT_SYMBOL_GPL(iommu_group_find);
Don't you need to do some reference counting here? Otherwise there's no
guarantee the returned pointer is still valid by the time it's used.
The interface should probably be iommu_group_get_by_id(). Thanks,
Alex
> +
> /**
> * iommu_group_get_iommudata - retrieve iommu_data registered for a group
> * @group: the group
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index f3b99e1..20281d5 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -113,6 +113,7 @@ struct iommu_ops {
> extern int bus_set_iommu(struct bus_type *bus, struct iommu_ops *ops);
> extern bool iommu_present(struct bus_type *bus);
> extern struct iommu_domain *iommu_domain_alloc(struct bus_type *bus);
> +extern struct iommu_group *iommu_group_find(int id);
> extern void iommu_domain_free(struct iommu_domain *domain);
> extern int iommu_attach_device(struct iommu_domain *domain,
> struct device *dev);
As IOMMU groups are exposed to the user space by their numbers,
the user space can use them in various kernel APIs so the kernel
might need an API to find a group by its ID.
As an example, QEMU VFIO on PPC64 platform needs it to associate
a logical bus number (LIOBN) with a specific IOMMU group in order
to support in-kernel handling of DMA map/unmap requests.
The patch adds the iommu_group_get_by_id(id) function which performs
such search.
Signed-off-by: Alexey Kardashevskiy <[email protected]>
---
drivers/iommu/iommu.c | 28 ++++++++++++++++++++++++++++
include/linux/iommu.h | 1 +
2 files changed, 29 insertions(+)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 1065a1a..531cbb5 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -204,6 +204,34 @@ again:
}
EXPORT_SYMBOL_GPL(iommu_group_alloc);
+struct iommu_group *iommu_group_get_by_id(int id)
+{
+ struct kobject *group_kobj;
+ struct iommu_group *grp;
+ const char *name;
+
+ if (!iommu_group_kset)
+ return NULL;
+
+ name = kasprintf(GFP_KERNEL, "%d", id);
+ if (!name)
+ return NULL;
+
+ group_kobj = kset_find_obj(iommu_group_kset, name);
+ kfree(name);
+
+ if (!group_kobj)
+ return NULL;
+
+ grp = container_of(group_kobj, struct iommu_group, kobj);
+ BUG_ON(grp->id != id);
+
+ kobject_get(grp->devices_kobj);
+
+ return grp;
+}
+EXPORT_SYMBOL_GPL(iommu_group_get_by_id);
+
/**
* iommu_group_get_iommudata - retrieve iommu_data registered for a group
* @group: the group
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index f3b99e1..00e5d7d 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -113,6 +113,7 @@ struct iommu_ops {
extern int bus_set_iommu(struct bus_type *bus, struct iommu_ops *ops);
extern bool iommu_present(struct bus_type *bus);
extern struct iommu_domain *iommu_domain_alloc(struct bus_type *bus);
+extern struct iommu_group *iommu_group_get_by_id(int id);
extern void iommu_domain_free(struct iommu_domain *domain);
extern int iommu_attach_device(struct iommu_domain *domain,
struct device *dev);
--
1.7.10.4
On Fri, 2013-03-22 at 17:49 +1100, Alexey Kardashevskiy wrote:
> As IOMMU groups are exposed to the user space by their numbers,
> the user space can use them in various kernel APIs so the kernel
> might need an API to find a group by its ID.
>
> As an example, QEMU VFIO on PPC64 platform needs it to associate
> a logical bus number (LIOBN) with a specific IOMMU group in order
> to support in-kernel handling of DMA map/unmap requests.
>
> The patch adds the iommu_group_get_by_id(id) function which performs
> such search.
>
> Signed-off-by: Alexey Kardashevskiy <[email protected]>
> ---
v2: <describe what changed>
> drivers/iommu/iommu.c | 28 ++++++++++++++++++++++++++++
> include/linux/iommu.h | 1 +
> 2 files changed, 29 insertions(+)
>
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index 1065a1a..531cbb5 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -204,6 +204,34 @@ again:
> }
> EXPORT_SYMBOL_GPL(iommu_group_alloc);
>
> +struct iommu_group *iommu_group_get_by_id(int id)
> +{
> + struct kobject *group_kobj;
> + struct iommu_group *grp;
This is named "group" everywhere else in this file.
> + const char *name;
> +
> + if (!iommu_group_kset)
> + return NULL;
> +
> + name = kasprintf(GFP_KERNEL, "%d", id);
> + if (!name)
> + return NULL;
> +
> + group_kobj = kset_find_obj(iommu_group_kset, name);
This does a kobject_get on group->kobj
> + kfree(name);
> +
> + if (!group_kobj)
> + return NULL;
> +
> + grp = container_of(group_kobj, struct iommu_group, kobj);
> + BUG_ON(grp->id != id);
> +
Here you want to exchange one reference for another, so first do the
get:
> + kobject_get(grp->devices_kobj);
Now you need to release the get from the find:
kobject_put(&group->kobj)
> +
> + return grp;
> +}
> +EXPORT_SYMBOL_GPL(iommu_group_get_by_id);
> +
> /**
> * iommu_group_get_iommudata - retrieve iommu_data registered for a group
> * @group: the group
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index f3b99e1..00e5d7d 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -113,6 +113,7 @@ struct iommu_ops {
> extern int bus_set_iommu(struct bus_type *bus, struct iommu_ops *ops);
> extern bool iommu_present(struct bus_type *bus);
> extern struct iommu_domain *iommu_domain_alloc(struct bus_type *bus);
> +extern struct iommu_group *iommu_group_get_by_id(int id);
> extern void iommu_domain_free(struct iommu_domain *domain);
> extern int iommu_attach_device(struct iommu_domain *domain,
> struct device *dev);
As IOMMU groups are exposed to the user space by their numbers,
the user space can use them in various kernel APIs so the kernel
might need an API to find a group by its ID.
As an example, QEMU VFIO on PPC64 platform needs it to associate
a logical bus number (LIOBN) with a specific IOMMU group in order
to support in-kernel handling of DMA map/unmap requests.
The patch adds the iommu_group_get_by_id(id) function which performs
such search.
v2: fixed reference counting.
Signed-off-by: Alexey Kardashevskiy <[email protected]>
---
drivers/iommu/iommu.c | 29 +++++++++++++++++++++++++++++
include/linux/iommu.h | 1 +
2 files changed, 30 insertions(+)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 1065a1a..0de83eb 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -204,6 +204,35 @@ again:
}
EXPORT_SYMBOL_GPL(iommu_group_alloc);
+struct iommu_group *iommu_group_get_by_id(int id)
+{
+ struct kobject *group_kobj;
+ struct iommu_group *group;
+ const char *name;
+
+ if (!iommu_group_kset)
+ return NULL;
+
+ name = kasprintf(GFP_KERNEL, "%d", id);
+ if (!name)
+ return NULL;
+
+ group_kobj = kset_find_obj(iommu_group_kset, name);
+ kfree(name);
+
+ if (!group_kobj)
+ return NULL;
+
+ group = container_of(group_kobj, struct iommu_group, kobj);
+ BUG_ON(group->id != id);
+
+ kobject_get(group->devices_kobj);
+ kobject_put(&group->kobj);
+
+ return group;
+}
+EXPORT_SYMBOL_GPL(iommu_group_get_by_id);
+
/**
* iommu_group_get_iommudata - retrieve iommu_data registered for a group
* @group: the group
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index f3b99e1..00e5d7d 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -113,6 +113,7 @@ struct iommu_ops {
extern int bus_set_iommu(struct bus_type *bus, struct iommu_ops *ops);
extern bool iommu_present(struct bus_type *bus);
extern struct iommu_domain *iommu_domain_alloc(struct bus_type *bus);
+extern struct iommu_group *iommu_group_get_by_id(int id);
extern void iommu_domain_free(struct iommu_domain *domain);
extern int iommu_attach_device(struct iommu_domain *domain,
struct device *dev);
--
1.7.10.4
On Mon, 2013-03-25 at 10:23 +1100, Alexey Kardashevskiy wrote:
> As IOMMU groups are exposed to the user space by their numbers,
> the user space can use them in various kernel APIs so the kernel
> might need an API to find a group by its ID.
>
> As an example, QEMU VFIO on PPC64 platform needs it to associate
> a logical bus number (LIOBN) with a specific IOMMU group in order
> to support in-kernel handling of DMA map/unmap requests.
>
> The patch adds the iommu_group_get_by_id(id) function which performs
> such search.
Subject: [PATCH v3]....
v2 was the last one, where's the changelog for v3?
> v2: fixed reference counting.
>
> Signed-off-by: Alexey Kardashevskiy <[email protected]>
> ---
Acked-by: Alex Williamson <[email protected]>
> drivers/iommu/iommu.c | 29 +++++++++++++++++++++++++++++
> include/linux/iommu.h | 1 +
> 2 files changed, 30 insertions(+)
>
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index 1065a1a..0de83eb 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -204,6 +204,35 @@ again:
> }
> EXPORT_SYMBOL_GPL(iommu_group_alloc);
>
> +struct iommu_group *iommu_group_get_by_id(int id)
> +{
> + struct kobject *group_kobj;
> + struct iommu_group *group;
> + const char *name;
> +
> + if (!iommu_group_kset)
> + return NULL;
> +
> + name = kasprintf(GFP_KERNEL, "%d", id);
> + if (!name)
> + return NULL;
> +
> + group_kobj = kset_find_obj(iommu_group_kset, name);
> + kfree(name);
> +
> + if (!group_kobj)
> + return NULL;
> +
> + group = container_of(group_kobj, struct iommu_group, kobj);
> + BUG_ON(group->id != id);
> +
> + kobject_get(group->devices_kobj);
> + kobject_put(&group->kobj);
> +
> + return group;
> +}
> +EXPORT_SYMBOL_GPL(iommu_group_get_by_id);
> +
> /**
> * iommu_group_get_iommudata - retrieve iommu_data registered for a group
> * @group: the group
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index f3b99e1..00e5d7d 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -113,6 +113,7 @@ struct iommu_ops {
> extern int bus_set_iommu(struct bus_type *bus, struct iommu_ops *ops);
> extern bool iommu_present(struct bus_type *bus);
> extern struct iommu_domain *iommu_domain_alloc(struct bus_type *bus);
> +extern struct iommu_group *iommu_group_get_by_id(int id);
> extern void iommu_domain_free(struct iommu_domain *domain);
> extern int iommu_attach_device(struct iommu_domain *domain,
> struct device *dev);
On 03/25/2013 10:28 AM, Alex Williamson wrote:
> On Mon, 2013-03-25 at 10:23 +1100, Alexey Kardashevskiy wrote:
>> As IOMMU groups are exposed to the user space by their numbers,
>> the user space can use them in various kernel APIs so the kernel
>> might need an API to find a group by its ID.
>>
>> As an example, QEMU VFIO on PPC64 platform needs it to associate
>> a logical bus number (LIOBN) with a specific IOMMU group in order
>> to support in-kernel handling of DMA map/unmap requests.
>>
>> The patch adds the iommu_group_get_by_id(id) function which performs
>> such search.
>
> Subject: [PATCH v3]....
>
> v2 was the last one, where's the changelog for v3?
>> v2: fixed reference counting.
>>
and changed function name...
>> Signed-off-by: Alexey Kardashevskiy<[email protected]>
>> ---
>
> Acked-by: Alex Williamson<[email protected]>
>
>> drivers/iommu/iommu.c | 29 +++++++++++++++++++++++++++++
>> include/linux/iommu.h | 1 +
>> 2 files changed, 30 insertions(+)
>>
>> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
>> index 1065a1a..0de83eb 100644
>> --- a/drivers/iommu/iommu.c
>> +++ b/drivers/iommu/iommu.c
>> @@ -204,6 +204,35 @@ again:
>> }
>> EXPORT_SYMBOL_GPL(iommu_group_alloc);
>>
>> +struct iommu_group *iommu_group_get_by_id(int id)
>> +{
>> + struct kobject *group_kobj;
>> + struct iommu_group *group;
>> + const char *name;
>> +
>> + if (!iommu_group_kset)
>> + return NULL;
>> +
>> + name = kasprintf(GFP_KERNEL, "%d", id);
>> + if (!name)
>> + return NULL;
>> +
>> + group_kobj = kset_find_obj(iommu_group_kset, name);
>> + kfree(name);
>> +
>> + if (!group_kobj)
>> + return NULL;
>> +
>> + group = container_of(group_kobj, struct iommu_group, kobj);
>> + BUG_ON(group->id != id);
>> +
>> + kobject_get(group->devices_kobj);
>> + kobject_put(&group->kobj);
>> +
>> + return group;
>> +}
>> +EXPORT_SYMBOL_GPL(iommu_group_get_by_id);
>> +
>> /**
>> * iommu_group_get_iommudata - retrieve iommu_data registered for a group
>> * @group: the group
>> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
>> index f3b99e1..00e5d7d 100644
>> --- a/include/linux/iommu.h
>> +++ b/include/linux/iommu.h
>> @@ -113,6 +113,7 @@ struct iommu_ops {
>> extern int bus_set_iommu(struct bus_type *bus, struct iommu_ops *ops);
>> extern bool iommu_present(struct bus_type *bus);
>> extern struct iommu_domain *iommu_domain_alloc(struct bus_type *bus);
>> +extern struct iommu_group *iommu_group_get_by_id(int id);
>> extern void iommu_domain_free(struct iommu_domain *domain);
>> extern int iommu_attach_device(struct iommu_domain *domain,
>> struct device *dev);
>
>
>
> _______________________________________________
> iommu mailing list
> [email protected]
> https://lists.linuxfoundation.org/mailman/listinfo/iommu
On Mon, Mar 25, 2013 at 10:23:49AM +1100, Alexey Kardashevskiy wrote:
> As IOMMU groups are exposed to the user space by their numbers,
> the user space can use them in various kernel APIs so the kernel
> might need an API to find a group by its ID.
>
> As an example, QEMU VFIO on PPC64 platform needs it to associate
> a logical bus number (LIOBN) with a specific IOMMU group in order
> to support in-kernel handling of DMA map/unmap requests.
>
> The patch adds the iommu_group_get_by_id(id) function which performs
> such search.
>
> v2: fixed reference counting.
>
> Signed-off-by: Alexey Kardashevskiy <[email protected]>
Applied to core branch, thanks Alexey.