Re: [PATCH v3 2/7] vfio: platform: add capability to register a reset function

[Arnd Bergmann]

On Friday 23 October 2015 14:37:10 Eric Auger wrote:
> +
> +void vfio_platform_unregister_reset(const char *compat)
> +{
> +   struct vfio_platform_reset_node *iter, *temp;
> +
> +   mutex_lock(_lock);
> +   list_for_each_entry_safe(iter, temp, _list, link) {
> +   if (!strcmp(iter->compat, compat)) {
> +   list_del(>link);
> +   break;
> +   }
> +   }
> +
> +   mutex_unlock(_lock);
> +}
> +EXPORT_SYMBOL_GPL(vfio_platform_unregister_reset);
> 

This is slightly unsafe in case you ever get two drivers that register
with the same compat string. If we care about that, we could pass
and compare both the string and the function pointer, or the
vfio_platform_reset_node.

Arnd
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Re: [PATCH v3 2/7] vfio: platform: add capability to register a reset function

[Eric Auger]

On 10/23/2015 03:07 PM, Arnd Bergmann wrote:
> On Friday 23 October 2015 14:37:10 Eric Auger wrote:
>> +
>> +void vfio_platform_unregister_reset(const char *compat)
>> +{
>> +   struct vfio_platform_reset_node *iter, *temp;
>> +
>> +   mutex_lock(_lock);
>> +   list_for_each_entry_safe(iter, temp, _list, link) {
>> +   if (!strcmp(iter->compat, compat)) {
>> +   list_del(>link);
>> +   break;
>> +   }
>> +   }
>> +
>> +   mutex_unlock(_lock);
>> +}
>> +EXPORT_SYMBOL_GPL(vfio_platform_unregister_reset);
>>
> 
> This is slightly unsafe in case you ever get two drivers that register
> with the same compat string. If we care about that, we could pass
> and compare both the string and the function pointer, or the
> vfio_platform_reset_node.
OK

Thanks

Eric
> 
>   Arnd
> 

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[PATCH v3 2/7] vfio: platform: add capability to register a reset function

[Eric Auger]

In preparation for subsequent changes in reset function lookup,
lets introduce a dynamic list of reset combos (compat string,
reset module, reset function). The list can be populated/voided with
two new functions, vfio_platform_register/unregister_reset. Those are
not yet used in this patch.

Signed-off-by: Eric Auger 

---

v2 -> v3:
- use goto out to have a single mutex_unlock
- implement vfio_platform_register_reset as a macro (suggested by Arnd)
- move reset_node struct declaration back to vfio_platform_private.h
- vfio_platform_unregister_reset does not return any value anymore

v1 -> v2:
- reset_list becomes static
- vfio_platform_register/unregister_reset take a const char * as compat
- fix node leak
- add reset_lock to protect the reset list manipulation
- move vfio_platform_reset_node declaration in vfio_platform_common.c
---
 drivers/vfio/platform/vfio_platform_common.c  | 26 ++
 drivers/vfio/platform/vfio_platform_private.h | 20 
 2 files changed, 46 insertions(+)

diff --git a/drivers/vfio/platform/vfio_platform_common.c 
b/drivers/vfio/platform/vfio_platform_common.c
index 184e9d2..8eccd30 100644
--- a/drivers/vfio/platform/vfio_platform_common.c
+++ b/drivers/vfio/platform/vfio_platform_common.c
@@ -27,6 +27,7 @@
 #define DRIVER_AUTHOR   "Antonios Motakis "
 #define DRIVER_DESC "VFIO platform base module"
 
+static LIST_HEAD(reset_list);
 static DEFINE_MUTEX(driver_lock);
 
 static const struct vfio_platform_reset_combo reset_lookup_table[] = {
@@ -578,6 +579,31 @@ struct vfio_platform_device 
*vfio_platform_remove_common(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(vfio_platform_remove_common);
 
+int __vfio_platform_register_reset(struct vfio_platform_reset_node *node)
+{
+   mutex_lock(_lock);
+   list_add(>link, _list);
+   mutex_unlock(_lock);
+   return 0;
+}
+EXPORT_SYMBOL_GPL(__vfio_platform_register_reset);
+
+void vfio_platform_unregister_reset(const char *compat)
+{
+   struct vfio_platform_reset_node *iter, *temp;
+
+   mutex_lock(_lock);
+   list_for_each_entry_safe(iter, temp, _list, link) {
+   if (!strcmp(iter->compat, compat)) {
+   list_del(>link);
+   break;
+   }
+   }
+
+   mutex_unlock(_lock);
+}
+EXPORT_SYMBOL_GPL(vfio_platform_unregister_reset);
+
 MODULE_VERSION(DRIVER_VERSION);
 MODULE_LICENSE("GPL v2");
 MODULE_AUTHOR(DRIVER_AUTHOR);
diff --git a/drivers/vfio/platform/vfio_platform_private.h 
b/drivers/vfio/platform/vfio_platform_private.h
index 7128690..277521a 100644
--- a/drivers/vfio/platform/vfio_platform_private.h
+++ b/drivers/vfio/platform/vfio_platform_private.h
@@ -71,6 +71,15 @@ struct vfio_platform_device {
int (*reset)(struct vfio_platform_device *vdev);
 };
 
+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;
+};
+
 struct vfio_platform_reset_combo {
const char *compat;
const char *reset_function_name;
@@ -90,4 +99,15 @@ extern int vfio_platform_set_irqs_ioctl(struct 
vfio_platform_device *vdev,
unsigned start, unsigned count,
void *data);
 
+extern int __vfio_platform_register_reset(struct vfio_platform_reset_node *n);
+extern void vfio_platform_unregister_reset(const char *compat);
+
+#define vfio_platform_register_reset(__compat, __reset)\
+static struct vfio_platform_reset_node __reset ## _node = {\
+   .owner = THIS_MODULE,   \
+   .compat = __compat, \
+   .reset = __reset,   \
+}; \
+__vfio_platform_register_reset(&__reset ## _node)
+
 #endif /* VFIO_PLATFORM_PRIVATE_H */
-- 
1.9.1

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