Re: [PATCH 1/5] VFIO: platform: add reset_list and register/unregister functions

2015-05-14 Thread Alex Williamson 
On Thu, 2015-05-14 at 10:25 +0200, Eric Auger wrote:
> Hi Alex,
> On 05/13/2015 08:32 PM, Alex Williamson wrote:
> > On Thu, 2015-05-07 at 16:27 +0200, Eric Auger wrote:
> >> vfio_platform_common now stores a lists of available reset functions.
> >> Two functions are exposed to register/unregister a reset function. A
> >> reset function is paired with a compat string.
> >>
> >> Signed-off-by: Eric Auger 
> >> ---
> >>  drivers/vfio/platform/vfio_platform_common.c  | 63 
> >> +++
> >>  drivers/vfio/platform/vfio_platform_private.h | 13 ++
> >>  2 files changed, 76 insertions(+)
> >>
> >> diff --git a/drivers/vfio/platform/vfio_platform_common.c 
> >> b/drivers/vfio/platform/vfio_platform_common.c
> >> index abcff7a..edbf24c 100644
> >> --- a/drivers/vfio/platform/vfio_platform_common.c
> >> +++ b/drivers/vfio/platform/vfio_platform_common.c
> >> @@ -23,6 +23,9 @@
> >>  
> >>  #include "vfio_platform_private.h"
> >>  
> >> +struct list_head reset_list;
> >> +LIST_HEAD(reset_list);
> >> +
> > 
> > Redundant?  Static?
> static, yes
> > 
> >>  static DEFINE_MUTEX(driver_lock);
> >>  
> >>  static int vfio_platform_regions_init(struct vfio_platform_device *vdev)
> >> @@ -511,6 +514,13 @@ EXPORT_SYMBOL_GPL(vfio_platform_probe_common);
> >>  struct vfio_platform_device *vfio_platform_remove_common(struct device 
> >> *dev)
> >>  {
> >>struct vfio_platform_device *vdev;
> >> +  struct vfio_platform_reset_node *iter, *tmp;
> >> +
> >> +  list_for_each_entry_safe(iter, tmp, &reset_list, link) {
> >> +  list_del(&iter->link);
> >> +  kfree(iter->compat);
> >> +  kfree(iter);
> >> +  }
> > 
> > 
> > This doesn't make sense.  We allow reset functions to be registered and
> > unregistered, but we forget them all when any device is released?!
> I acknowledge indeed. Can I rely on the reset module exit and associated
> unregister_reset or shall I take this action in the vfio driver itself,
> core?

If we were to load the reset modules via request_module() from
vfio-platform, I think they would stay loaded as long as vfio-platform
is loaded and automatically unload if vfio-platform is unloaded.  Our
reference via try_module_get() for an in-use reset function should
prevent the module from being unloaded while we're dependent on it.  I
think that covers everything we need.  A user is free to rmmod the reset
module, but if it's in use it shouldn't work, and we can request it
again for the next device.  

> >>  
> >>vdev = vfio_del_group_dev(dev);
> >>if (vdev)
> >> @@ -519,3 +529,56 @@ struct vfio_platform_device 
> >> *vfio_platform_remove_common(struct device *dev)
> >>return vdev;
> >>  }
> >>  EXPORT_SYMBOL_GPL(vfio_platform_remove_common);
> >> +
> >> +int vfio_platform_register_reset(char *compat, struct module *reset_owner,
> >> +   vfio_platform_reset_fn_t reset)
> >> +{
> >> +  struct vfio_platform_reset_node *node, *iter;
> >> +  bool found = false;
> >> +
> >> +  list_for_each_entry(iter, &reset_list, link) {
> >> +  if (!strcmp(iter->compat, compat)) {
> >> +  found = true;
> > 
> > Just return errno here
> ok
> > 
> >> +  break;
> >> +  }
> >> +  }
> >> +  if (found)
> >> +  return -EINVAL;
> >> +
> >> +  node = kmalloc(sizeof(*node), GFP_KERNEL);
> >> +  if (!node)
> >> +  return -ENOMEM;
> >> +
> >> +  node->compat = kstrdup(compat, GFP_KERNEL);
> >> +  if (!node->compat)
> > 
> > Leaking node
> ok
> > 
> >> +  return -ENOMEM;
> >> +
> >> +  node->owner = reset_owner;
> >> +  node->reset = reset;
> >> +
> >> +  list_add(&node->link, &reset_list);
> > 
> > Isn't this racy?  Don't we need some locks around the list?
> I will add a lock to protect access to the list.
> > 
> >> +  return 0;
> >> +}
> >> +EXPORT_SYMBOL_GPL(vfio_platform_register_reset);
> >> +
> >> +int vfio_platform_unregister_reset(char *compat)
> >> +{
> >> +  struct vfio_platform_reset_node *iter;
> >> +  bool found = false;
> >> +
> >> +  list_for_each_entry(iter, &reset_list, link) {
> >> +  if (!strcmp(iter->compat, compat)) {
> > 
> > Return errno here
> ok
> > 
> >> +  found = true;
> >> +  break;
> >> +  }
> >> +  }
> >> +  if (!found)
> >> +  return -EINVAL;
> >> +
> >> +  list_del(&iter->link);
> > 
> > Racy
> > 
> >> +  kfree(iter->compat);
> >> +  kfree(iter);
> >> +  return 0;
> >> +}
> >> +EXPORT_SYMBOL_GPL(vfio_platform_unregister_reset);
> >> +
> >> diff --git a/drivers/vfio/platform/vfio_platform_private.h 
> >> b/drivers/vfio/platform/vfio_platform_private.h
> >> index 5d31e04..da2d60b 100644
> >> --- a/drivers/vfio/platform/vfio_platform_private.h
> >> +++ b/drivers/vfio/platform/vfio_platform_private.h
> >> @@ -69,6 +69,15 @@ struct vfio_platform_device {
> >>int (*get_irq)(struct vfio_platform_device *vdev, int i);
> >>  };
> >>  
> >> +typedef int (*vfio_platform_reset_fn_t)(struct vfio_platform_device

Re: [PATCH 1/5] VFIO: platform: add reset_list and register/unregister functions

2015-05-14 Thread Eric Auger 
Hi Alex,
On 05/13/2015 08:32 PM, Alex Williamson wrote:
> On Thu, 2015-05-07 at 16:27 +0200, Eric Auger wrote:
>> vfio_platform_common now stores a lists of available reset functions.
>> Two functions are exposed to register/unregister a reset function. A
>> reset function is paired with a compat string.
>>
>> Signed-off-by: Eric Auger 
>> ---
>>  drivers/vfio/platform/vfio_platform_common.c  | 63 
>> +++
>>  drivers/vfio/platform/vfio_platform_private.h | 13 ++
>>  2 files changed, 76 insertions(+)
>>
>> diff --git a/drivers/vfio/platform/vfio_platform_common.c 
>> b/drivers/vfio/platform/vfio_platform_common.c
>> index abcff7a..edbf24c 100644
>> --- a/drivers/vfio/platform/vfio_platform_common.c
>> +++ b/drivers/vfio/platform/vfio_platform_common.c
>> @@ -23,6 +23,9 @@
>>  
>>  #include "vfio_platform_private.h"
>>  
>> +struct list_head reset_list;
>> +LIST_HEAD(reset_list);
>> +
> 
> Redundant?  Static?
static, yes
> 
>>  static DEFINE_MUTEX(driver_lock);
>>  
>>  static int vfio_platform_regions_init(struct vfio_platform_device *vdev)
>> @@ -511,6 +514,13 @@ EXPORT_SYMBOL_GPL(vfio_platform_probe_common);
>>  struct vfio_platform_device *vfio_platform_remove_common(struct device *dev)
>>  {
>>  struct vfio_platform_device *vdev;
>> +struct vfio_platform_reset_node *iter, *tmp;
>> +
>> +list_for_each_entry_safe(iter, tmp, &reset_list, link) {
>> +list_del(&iter->link);
>> +kfree(iter->compat);
>> +kfree(iter);
>> +}
> 
> 
> This doesn't make sense.  We allow reset functions to be registered and
> unregistered, but we forget them all when any device is released?!
I acknowledge indeed. Can I rely on the reset module exit and associated
unregister_reset or shall I take this action in the vfio driver itself,
core?
> 
>>  
>>  vdev = vfio_del_group_dev(dev);
>>  if (vdev)
>> @@ -519,3 +529,56 @@ struct vfio_platform_device 
>> *vfio_platform_remove_common(struct device *dev)
>>  return vdev;
>>  }
>>  EXPORT_SYMBOL_GPL(vfio_platform_remove_common);
>> +
>> +int vfio_platform_register_reset(char *compat, struct module *reset_owner,
>> + vfio_platform_reset_fn_t reset)
>> +{
>> +struct vfio_platform_reset_node *node, *iter;
>> +bool found = false;
>> +
>> +list_for_each_entry(iter, &reset_list, link) {
>> +if (!strcmp(iter->compat, compat)) {
>> +found = true;
> 
> Just return errno here
ok
> 
>> +break;
>> +}
>> +}
>> +if (found)
>> +return -EINVAL;
>> +
>> +node = kmalloc(sizeof(*node), GFP_KERNEL);
>> +if (!node)
>> +return -ENOMEM;
>> +
>> +node->compat = kstrdup(compat, GFP_KERNEL);
>> +if (!node->compat)
> 
> Leaking node
ok
> 
>> +return -ENOMEM;
>> +
>> +node->owner = reset_owner;
>> +node->reset = reset;
>> +
>> +list_add(&node->link, &reset_list);
> 
> Isn't this racy?  Don't we need some locks around the list?
I will add a lock to protect access to the list.
> 
>> +return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(vfio_platform_register_reset);
>> +
>> +int vfio_platform_unregister_reset(char *compat)
>> +{
>> +struct vfio_platform_reset_node *iter;
>> +bool found = false;
>> +
>> +list_for_each_entry(iter, &reset_list, link) {
>> +if (!strcmp(iter->compat, compat)) {
> 
> Return errno here
ok
> 
>> +found = true;
>> +break;
>> +}
>> +}
>> +if (!found)
>> +return -EINVAL;
>> +
>> +list_del(&iter->link);
> 
> Racy
> 
>> +kfree(iter->compat);
>> +kfree(iter);
>> +return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(vfio_platform_unregister_reset);
>> +
>> diff --git a/drivers/vfio/platform/vfio_platform_private.h 
>> b/drivers/vfio/platform/vfio_platform_private.h
>> index 5d31e04..da2d60b 100644
>> --- a/drivers/vfio/platform/vfio_platform_private.h
>> +++ b/drivers/vfio/platform/vfio_platform_private.h
>> @@ -69,6 +69,15 @@ struct vfio_platform_device {
>>  int (*get_irq)(struct vfio_platform_device *vdev, int i);
>>  };
>>  
>> +typedef int (*vfio_platform_reset_fn_t)(struct vfio_platform_device *vdev);
> 
> Seems like this ought to be in a non-private header if we're exporting
> the [un]register functions.
I considered the vfio reset modules were internal to the vfio subsystem
but if you prefer I can expose that in vfio.h. I guess
register/unregister should become an external API then?

Thanks

Eric
>> +
>> +struct vfio_platform_reset_node {
>> +struct list_head link;
>> +char *compat;
>> +struct module *owner;
>> +vfio_platform_reset_fn_t reset;
>> +};
>> +
>>  extern int vfio_platform_probe_common(struct vfio_platform_device *vdev,
>>struct device *dev);
>>  extern struct vfio_platform_device *vfio_platform_remove_common
>> @@ -82,4 +91,8 @@ extern int vfio_platform_set_irqs_ioctl(struc

Re: [PATCH 1/5] VFIO: platform: add reset_list and register/unregister functions

2015-05-13 Thread Alex Williamson 
On Thu, 2015-05-07 at 16:27 +0200, Eric Auger wrote:
> vfio_platform_common now stores a lists of available reset functions.
> Two functions are exposed to register/unregister a reset function. A
> reset function is paired with a compat string.
> 
> Signed-off-by: Eric Auger 
> ---
>  drivers/vfio/platform/vfio_platform_common.c  | 63 
> +++
>  drivers/vfio/platform/vfio_platform_private.h | 13 ++
>  2 files changed, 76 insertions(+)
> 
> diff --git a/drivers/vfio/platform/vfio_platform_common.c 
> b/drivers/vfio/platform/vfio_platform_common.c
> index abcff7a..edbf24c 100644
> --- a/drivers/vfio/platform/vfio_platform_common.c
> +++ b/drivers/vfio/platform/vfio_platform_common.c
> @@ -23,6 +23,9 @@
>  
>  #include "vfio_platform_private.h"
>  
> +struct list_head reset_list;
> +LIST_HEAD(reset_list);
> +

Redundant?  Static?

>  static DEFINE_MUTEX(driver_lock);
>  
>  static int vfio_platform_regions_init(struct vfio_platform_device *vdev)
> @@ -511,6 +514,13 @@ EXPORT_SYMBOL_GPL(vfio_platform_probe_common);
>  struct vfio_platform_device *vfio_platform_remove_common(struct device *dev)
>  {
>   struct vfio_platform_device *vdev;
> + struct vfio_platform_reset_node *iter, *tmp;
> +
> + list_for_each_entry_safe(iter, tmp, &reset_list, link) {
> + list_del(&iter->link);
> + kfree(iter->compat);
> + kfree(iter);
> + }


This doesn't make sense.  We allow reset functions to be registered and
unregistered, but we forget them all when any device is released?!

>  
>   vdev = vfio_del_group_dev(dev);
>   if (vdev)
> @@ -519,3 +529,56 @@ struct vfio_platform_device 
> *vfio_platform_remove_common(struct device *dev)
>   return vdev;
>  }
>  EXPORT_SYMBOL_GPL(vfio_platform_remove_common);
> +
> +int vfio_platform_register_reset(char *compat, struct module *reset_owner,
> +  vfio_platform_reset_fn_t reset)
> +{
> + struct vfio_platform_reset_node *node, *iter;
> + bool found = false;
> +
> + list_for_each_entry(iter, &reset_list, link) {
> + if (!strcmp(iter->compat, compat)) {
> + found = true;

Just return errno here

> + break;
> + }
> + }
> + if (found)
> + return -EINVAL;
> +
> + node = kmalloc(sizeof(*node), GFP_KERNEL);
> + if (!node)
> + return -ENOMEM;
> +
> + node->compat = kstrdup(compat, GFP_KERNEL);
> + if (!node->compat)

Leaking node

> + return -ENOMEM;
> +
> + node->owner = reset_owner;
> + node->reset = reset;
> +
> + list_add(&node->link, &reset_list);

Isn't this racy?  Don't we need some locks around the list?

> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(vfio_platform_register_reset);
> +
> +int vfio_platform_unregister_reset(char *compat)
> +{
> + struct vfio_platform_reset_node *iter;
> + bool found = false;
> +
> + list_for_each_entry(iter, &reset_list, link) {
> + if (!strcmp(iter->compat, compat)) {

Return errno here

> + found = true;
> + break;
> + }
> + }
> + if (!found)
> + return -EINVAL;
> +
> + list_del(&iter->link);

Racy

> + kfree(iter->compat);
> + kfree(iter);
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(vfio_platform_unregister_reset);
> +
> diff --git a/drivers/vfio/platform/vfio_platform_private.h 
> b/drivers/vfio/platform/vfio_platform_private.h
> index 5d31e04..da2d60b 100644
> --- a/drivers/vfio/platform/vfio_platform_private.h
> +++ b/drivers/vfio/platform/vfio_platform_private.h
> @@ -69,6 +69,15 @@ struct vfio_platform_device {
>   int (*get_irq)(struct vfio_platform_device *vdev, int i);
>  };
>  
> +typedef int (*vfio_platform_reset_fn_t)(struct vfio_platform_device *vdev);

Seems like this ought to be in a non-private header if we're exporting
the [un]register functions.
> +
> +struct vfio_platform_reset_node {
> + struct list_head link;
> + char *compat;
> + struct module *owner;
> + vfio_platform_reset_fn_t reset;
> +};
> +
>  extern int vfio_platform_probe_common(struct vfio_platform_device *vdev,
> struct device *dev);
>  extern struct vfio_platform_device *vfio_platform_remove_common
> @@ -82,4 +91,8 @@ extern int vfio_platform_set_irqs_ioctl(struct 
> vfio_platform_device *vdev,
>   unsigned start, unsigned count,
>   void *data);
>  
> +extern int vfio_platform_register_reset(char *compat, struct module *owner,
> + vfio_platform_reset_fn_t reset);
> +extern int vfio_platform_unregister_reset(char *compat);
> +
>  #endif /* VFIO_PLATFORM_PRIVATE_H */



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[PATCH 1/5] VFIO: platform: add reset_list and register/unregister functions

2015-05-07 Thread Eric Auger 
vfio_platform_common now stores a lists of available reset functions.
Two functions are exposed to register/unregister a reset function. A
reset function is paired with a compat string.

Signed-off-by: Eric Auger 
---
 drivers/vfio/platform/vfio_platform_common.c  | 63 +++
 drivers/vfio/platform/vfio_platform_private.h | 13 ++
 2 files changed, 76 insertions(+)

diff --git a/drivers/vfio/platform/vfio_platform_common.c 
b/drivers/vfio/platform/vfio_platform_common.c
index abcff7a..edbf24c 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -23,6 +23,9 @@
 
 #include "vfio_platform_private.h"
 
+struct list_head reset_list;
+LIST_HEAD(reset_list);
+
 static DEFINE_MUTEX(driver_lock);
 
 static int vfio_platform_regions_init(struct vfio_platform_device *vdev)
@@ -511,6 +514,13 @@ EXPORT_SYMBOL_GPL(vfio_platform_probe_common);
 struct vfio_platform_device *vfio_platform_remove_common(struct device *dev)
 {
struct vfio_platform_device *vdev;
+   struct vfio_platform_reset_node *iter, *tmp;
+
+   list_for_each_entry_safe(iter, tmp, &reset_list, link) {
+   list_del(&iter->link);
+   kfree(iter->compat);
+   kfree(iter);
+   }
 
vdev = vfio_del_group_dev(dev);
if (vdev)
@@ -519,3 +529,56 @@ struct vfio_platform_device 
*vfio_platform_remove_common(struct device *dev)
return vdev;
 }
 EXPORT_SYMBOL_GPL(vfio_platform_remove_common);
+
+int vfio_platform_register_reset(char *compat, struct module *reset_owner,
+vfio_platform_reset_fn_t reset)
+{
+   struct vfio_platform_reset_node *node, *iter;
+   bool found = false;
+
+   list_for_each_entry(iter, &reset_list, link) {
+   if (!strcmp(iter->compat, compat)) {
+   found = true;
+   break;
+   }
+   }
+   if (found)
+   return -EINVAL;
+
+   node = kmalloc(sizeof(*node), GFP_KERNEL);
+   if (!node)
+   return -ENOMEM;
+
+   node->compat = kstrdup(compat, GFP_KERNEL);
+   if (!node->compat)
+   return -ENOMEM;
+
+   node->owner = reset_owner;
+   node->reset = reset;
+
+   list_add(&node->link, &reset_list);
+   return 0;
+}
+EXPORT_SYMBOL_GPL(vfio_platform_register_reset);
+
+int vfio_platform_unregister_reset(char *compat)
+{
+   struct vfio_platform_reset_node *iter;
+   bool found = false;
+
+   list_for_each_entry(iter, &reset_list, link) {
+   if (!strcmp(iter->compat, compat)) {
+   found = true;
+   break;
+   }
+   }
+   if (!found)
+   return -EINVAL;
+
+   list_del(&iter->link);
+   kfree(iter->compat);
+   kfree(iter);
+   return 0;
+}
+EXPORT_SYMBOL_GPL(vfio_platform_unregister_reset);
+
diff --git a/drivers/vfio/platform/vfio_platform_private.h 
b/drivers/vfio/platform/vfio_platform_private.h
index 5d31e04..da2d60b 100644
--- a/drivers/vfio/platform/vfio_platform_private.h
+++ b/drivers/vfio/platform/vfio_platform_private.h
@@ -69,6 +69,15 @@ struct vfio_platform_device {
int (*get_irq)(struct vfio_platform_device *vdev, int i);
 };
 
+typedef int (*vfio_platform_reset_fn_t)(struct vfio_platform_device *vdev);
+
+struct vfio_platform_reset_node {
+   struct list_head link;
+   char *compat;
+   struct module *owner;
+   vfio_platform_reset_fn_t reset;
+};
+
 extern int vfio_platform_probe_common(struct vfio_platform_device *vdev,
  struct device *dev);
 extern struct vfio_platform_device *vfio_platform_remove_common
@@ -82,4 +91,8 @@ extern int vfio_platform_set_irqs_ioctl(struct 
vfio_platform_device *vdev,
unsigned start, unsigned count,
void *data);
 
+extern int vfio_platform_register_reset(char *compat, struct module *owner,
+   vfio_platform_reset_fn_t reset);
+extern int vfio_platform_unregister_reset(char *compat);
+
 #endif /* VFIO_PLATFORM_PRIVATE_H */
-- 
1.9.1

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