[RFC][PATCH 5/6] staging: android: ion: Add an ioctl for ABI checking

[Laura Abbott <labbott@redhat.com>]

The current Ion ioctls lack a good way to tell what ioctls are
available. Introduce an ioctl to give an ABI version. This way when the
ABI inevitably gets screwed up userspace will have a way to tell what
version of the screw up is available.

Signed-off-by: Laura Abbott <labbott@redhat.com>
---
 drivers/staging/android/ion/ion-ioctl.c |  6 ++++++
 drivers/staging/android/uapi/ion.h      | 23 +++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/drivers/staging/android/ion/ion-ioctl.c b/drivers/staging/android/ion/ion-ioctl.c
index 341ba7d..45b89e8 100644
--- a/drivers/staging/android/ion/ion-ioctl.c
+++ b/drivers/staging/android/ion/ion-ioctl.c
@@ -48,6 +48,7 @@ long ion_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		struct ion_allocation_data allocation;
 		struct ion_handle_data handle;
 		struct ion_custom_data custom;
+		struct ion_abi_version abi_version;
 	} data;
 
 	dir = ion_ioctl_dir(cmd);
@@ -129,6 +130,11 @@ long ion_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 						data.custom.arg);
 		break;
 	}
+	case ION_IOC_ABI_VERSION:
+	{
+		data.abi_version.abi_version = ION_ABI_VERSION;
+		break;
+	}
 	default:
 		return -ENOTTY;
 	}
diff --git a/drivers/staging/android/uapi/ion.h b/drivers/staging/android/uapi/ion.h
index a9c4e8b..145005f 100644
--- a/drivers/staging/android/uapi/ion.h
+++ b/drivers/staging/android/uapi/ion.h
@@ -19,6 +19,7 @@
 
 #include <linux/ioctl.h>
 #include <linux/types.h>
+#include <linux/version.h>
 
 typedef int ion_user_handle_t;
 
@@ -128,6 +129,19 @@ struct ion_custom_data {
 	unsigned long arg;
 };
 
+/**
+ * struct ion_abi_version
+ *
+ *  @version - current ABI version
+ */
+
+#define ION_ABI_VERSION                KERNEL_VERSION(0, 1, 0)
+
+struct ion_abi_version {
+	__u32 abi_version;
+	__u32 reserved;
+};
+
 #define ION_IOC_MAGIC		'I'
 
 /**
@@ -194,4 +208,13 @@ struct ion_custom_data {
  */
 #define ION_IOC_CUSTOM		_IOWR(ION_IOC_MAGIC, 6, struct ion_custom_data)
 
+/**
+ * DOC: ION_IOC_ABI_VERSION - return ABI version
+ *
+ * Returns the ABI version of this driver.
+ */
+#define ION_IOC_ABI_VERSION    _IOR(ION_IOC_MAGIC, 8, \
+					struct ion_abi_version)
+
+
 #endif /* _UAPI_LINUX_ION_H */
-- 
2.5.5